JP2018110793A - Low-temperature-steam formaldehyde sterilization device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-temperature-steam formaldehyde sterilization device using a water seal-type vacuum pump, which prevents the dissolution of formaldehyde into seal water, and does not require a large amount of water for formaldehyde dilution, leading to reduced running cost.SOLUTION: A low-temperature-steam formaldehyde sterilization device has a sterilization tank 2 in which a material to be sterilized is stored, a water seal-type vacuum pump 3 that sucks and discharges a gas in the sterilization tank 2 to the external, and a catalyst reactor 6 that is provided in an exhaust path 9 from the sterilization tank 2 to the vacuum pump 3 and decomposes formaldehyde. Preferably, changing the course of the exhaust path 9 can change the manner of discharge of the gas in the sterilization tank 2, that is, whether it is discharged via the catalyst reactor 6 or not via the catalyst reactor 6.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a low temperature steam formaldehyde (LTSF) sterilizer.

  Conventionally, as disclosed in Patent Document 1 below, a low-temperature steam formaldehyde sterilization apparatus that sterilizes a sterilized product with formaldehyde-containing water vapor in a sterilization tank under vacuum is known. In this apparatus, since water vapor is handled under vacuum, a water-sealed vacuum pump is preferably used instead of a dry type.

  When a water-sealed vacuum pump is used, formaldehyde dissolves in the sealed water, so even if diluted with a large amount of water, formaldehyde will spill out, which is not preferable from the viewpoint of environmental protection. In addition, when formaldehyde is diluted with a large amount of water, the amount of water used increases and the running cost increases. Although an environmental purification microreactor system disclosed in the following Patent Document 2 has also been proposed, it is basically applied to a sterilizer using ethylene oxide gas (or a mixed gas with carbon dioxide) and is water-sealed. The use of a vacuum pump is also denied (paragraphs [0003] and [0008] of Patent Document 2), and is not applicable to a low-temperature steam formaldehyde sterilizer.

JP 2014-233503 A (paragraphs [0002], [0026], [0036]) Japanese Patent Laying-Open No. 2005-254194 (FIG. 1)

  The problem to be solved by the present invention is to provide an environment-friendly device in a low-temperature steam formaldehyde sterilization apparatus using a water-sealed vacuum pump by preventing the formaldehyde from entering the sealed water and thus drainage. . It is another object of the present invention to provide a device that does not require a large amount of water for dilution and can reduce running costs.

  The present invention has been made to solve the above problems, and the invention according to claim 1 is a sterilization tank in which a sterilized material is stored, and a water-sealed type that sucks and discharges the gas in the sterilization tank to the outside. A low-temperature steam formaldehyde sterilization apparatus comprising: a vacuum pump; and a catalytic reactor provided in an exhaust path from the sterilization tank to the vacuum pump to decompose formaldehyde.

  According to the first aspect of the present invention, since the formaldehyde can be decomposed by providing the catalytic reactor in the exhaust path from the sterilization tank to the vacuum pump, the inflow of formaldehyde to the vacuum pump can be prevented. Thereby, it is possible to prevent the formaldehyde from entering into the sealing water of the vacuum pump and thus the waste water. Further, a large amount of water for diluting formaldehyde is not required, and the running cost can be reduced.

  According to a second aspect of the present invention, switching between whether the gas in the sterilization tank is discharged via the catalytic reactor or not via the catalytic reactor by changing the flow path of the exhaust passage. The low-temperature steam formaldehyde sterilizer according to claim 1, which is made possible.

  According to invention of Claim 2, when discharging | emitting the gas in a sterilization tank with a vacuum pump, it can switch whether it discharges | emits via a catalyst reactor or not via a catalyst reactor. When discharging through the catalytic reactor, formaldehyde can be decomposed in the catalytic reactor, and when discharging without passing through the catalytic reactor, the pressure loss is reduced by the amount not passing through the catalytic reactor, and the exhaust time Can be shortened.

  The invention according to claim 3 includes a gas replacement step of repeatedly reducing the pressure in the sterilization tank and a return pressure by introducing formaldehyde gas, a sterilization step of maintaining the sterilization tank at a sterilization temperature for a sterilization time, A desorption step of repeating the depressurization of the gas and a return pressure by the introduction of water vapor, and an air desorption step of repeating the depressurization in the sterilization tank and the return pressure by the introduction of air in sequence, 3. The low temperature steam formaldehyde sterilizer according to claim 2, wherein in the vapor desorption step, the gas in the sterilization tank is discharged through the catalytic reactor when the pressure in the sterilization tank is reduced. .

  According to the third aspect of the invention, pretreatment, sterilization, and post-treatment can be achieved by operating by sequentially including a gas replacement step, a sterilization step, a vapor desorption step, and an air desorption step. Further, at least in the gas replacement step and the vapor desorption step, formaldehyde can be decomposed and rendered harmless by passing the gas in the sterilization tank through the catalyst reactor during decompression in the sterilization tank.

  According to a fourth aspect of the present invention, the exhaust path from the inside of the sterilization tank branches to the first exhaust path and the second exhaust path, and then merges again and is connected to the vacuum pump. In the exhaust path, an inlet valve, a catalytic reactor, a communication valve, a tank and an outlet valve are provided in order, and switching between exhausting through the first exhaust path or exhausting through the second exhaust path When exhausting through the first exhaust path, the outlet valve is opened with the inlet valve and the communication valve closed, and the inside of the tank is decompressed, and then the outlet valve is closed. In the state, the inlet valve and the communication valve are opened to depressurize the inside of the sterilization tank, and then the inlet valve and the communication valve are closed again to open the outlet valve and depressurize the inside of the tank. The low-temperature steam formaldehyde sterilizer according to claim 2 or 3, characterized in that That.

  According to the invention described in claim 4, the tank and the vacuum pump are connected in a state where communication between the tank and the sterilization tank (specifically, the tank and the catalyst reactor, and the catalyst reactor and the sterilization tank) is interrupted. After reducing the pressure in the tank by communication, the tank and the sterilization tank are communicated with each other in a state where the communication between the tank and the vacuum pump is cut off, and the pressure in the sterilization tank is reduced. Thereby, compared with the case where the inside of a sterilization tank is directly pressure-reduced with a vacuum pump, reduction of a pressure loss can be aimed at. Moreover, by performing the pressure reduction in the tank as desired, it is possible to prevent damage when the vacuum pressure is applied to the catalyst reactor (for example, dropping of the catalyst from the reaction vessel). Thereafter, the water vapor remaining in the tank can be discharged by reducing the pressure in the tank by connecting the tank and the vacuum pump again in a state where the communication between the tank and the sterilization tank is shut off.

  According to a fifth aspect of the present invention, the catalytic reactor has a double tube structure including an inner cylinder and an outer cylinder, and a catalyst is provided in the inner cylinder, while the outer cylinder is heated by a heater, The low-temperature steam formaldehyde according to any one of claims 1 to 4, wherein the gas from the inside of the sterilization tank is passed through the inner cylinder after passing through the gap between the inner cylinder and the outer cylinder. Sterilizer.

  According to the invention described in claim 5, the catalytic reactor has a double-pipe structure composed of an inner cylinder and an outer cylinder, and after passing the gas from the sterilization tank through the gap between the inner cylinder and the outer cylinder Since it passes through the catalyst in the inner cylinder, a compact configuration can be achieved. Further, by heating the outer cylinder with a heater, the gas from the inside of the sterilization tank can be heated and sent to the catalyst, so that the decomposition of formaldehyde in the catalyst can be achieved reliably. On the other hand, since the catalyst itself is not directly heated by the heater, the ignition of formaldehyde can be prevented.

  Furthermore, the invention described in claim 6 is characterized in that the gas from the inside of the sterilization tank is passed through the catalytic reactor after mixed with air from the outside. 2. A low-temperature steam formaldehyde sterilizer according to claim 1.

  Oxygen is required for the decomposition reaction of formaldehyde. However, if sterilization is performed under vacuum after the air is removed from the sterilization tank, oxygen will be insufficient even if formaldehyde is passed through the catalytic reactor during exhaustion from the sterilization tank. May cause the expected disassembly. However, according to the invention described in claim 6, since air is mixed into the gas from the inside of the sterilization tank and passed through the catalytic reactor, it is possible to reliably decompose formaldehyde.

  According to the present invention, in a low-temperature steam formaldehyde sterilization apparatus using a water-sealed vacuum pump, it is possible to prevent the formaldehyde from infiltrating into the sealed water and thus to the wastewater, thereby making the environment friendly. In addition, a large amount of water for dilution is not required, and the running cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the low temperature steam formaldehyde sterilizer of one Example of this invention, and it has shown one part in cross section. It is the schematic which shows an example of the operation | movement process of the low temperature steam formaldehyde sterilizer of FIG. 1, and has shown the relationship between the pressure P in a sterilization tank, and the elapsed time t. It is a figure which shows the modification of the low temperature steam formaldehyde sterilizer of FIG. It is a schematic sectional drawing which shows an example of the catalytic reactor used for the low temperature steam formaldehyde sterilizer of FIG. It is a schematic sectional drawing which shows the other example of the catalytic reactor used for the low temperature steam formaldehyde sterilizer of FIG.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a low-temperature steam formaldehyde sterilization apparatus 1 according to an embodiment of the present invention, and a part thereof is shown in cross section.

  The low-temperature steam formaldehyde sterilization apparatus 1 of the present embodiment includes a sterilization tank 2 in which a sterilized material is stored, a water-sealed vacuum pump 3 that sucks and discharges the gas in the sterilization tank 2 to the outside, and the sterilization tank 2 Water vapor and formaldehyde gas introduction means 4, outside air introduction means 5 into the sterilization tank 2, catalytic reactor 6 for decomposing formaldehyde to the outside of the sterilization tank 2, and control means (not shown).

  The sterilized material is not particularly limited, but is typically a medical instrument such as forceps or a tube. The sterilized product may be accommodated in the sterilization tank 2 in a state of being put in a sterilization packaging material.

  The sterilization tank 2 is a hollow container that can withstand decompression of the internal space, and is typically formed in a substantially rectangular box shape. The sterilization tank 2 can be opened and closed by a door (not shown). By opening the door, sterilized materials can be taken in and out of the sterilization tank 2, and by closing the door, the sterilization tank 2 can be closed airtight.

  The inside of the sterilization tank 2 can be heated with a heater (not shown). The heater of the sterilization tank 2 is not particularly limited in its configuration, and may be, for example, a steam jacket. In the present embodiment, the heater is formed of a heat tape provided on the outer wall of the sterilization tank 2. The inside of the sterilization tank 2 can be maintained at a desired temperature by controlling on / off or capacity of the heater.

  The sterilization tank 2 is provided with a pressure sensor 7 for detecting the pressure in the sterilization tank 2 and a temperature sensor 8 for detecting the temperature in the sterilization tank 2. Although details will be described later, the decompression or return pressure in the sterilization tank 2 can be controlled based on the detected pressure of the pressure sensor 7, and the heater of the sterilization tank 2 can be controlled based on the detected temperature of the temperature sensor 8. it can.

  As is well known, the water-sealed vacuum pump 3 is operated while being supplied with water called sealed water. Specifically, in this embodiment, an impeller (not shown) having blades arranged radially is installed eccentrically with the casing in a cylindrical casing (reference numeral omitted) to which sealed water is supplied. . Therefore, when the impeller is rotated at a high speed, a water ring is formed in the casing, and the impeller and the casing are eccentric. Therefore, the internal gas repeats expansion and compression every time it rotates once. Therefore, by providing the intake port 3a and the exhaust port 3b at appropriate positions of the casing, it is possible to intake and exhaust external gas. The casing is further provided with a water supply port (not shown), and sealed water is supplied into the casing from the water supply port. A water supply valve (not shown) to the water supply port is opened and closed in conjunction with the start and stop of the vacuum pump 3. In addition, the used sealing water is also discharged | emitted from the exhaust port 3b.

  The suction port 3 a of the vacuum pump 3 is connected to the sterilization tank 2 through the exhaust path 9. A catalyst reactor 6 is provided in the exhaust path 9 from the sterilization tank 2 to the vacuum pump 3. At this time, preferably, the gas from the inside of the sterilization tank 2 can be switched between being discharged via the catalytic reactor 6 or discharged without going through the catalytic reactor 6. Specifically, the exhaust path 9 from the inside of the sterilization tank 2 branches into a first exhaust path 9a and a second exhaust path 9b, and then merges again and is connected to the vacuum pump 3. An inlet valve 10, a catalytic reactor 6 and an outlet valve 11 are provided in this order in the first exhaust passage 9a, and a bypass valve 12 is provided in the second exhaust passage 9b. Therefore, if the inlet valve 10 and the outlet valve 11 are opened with the bypass valve 12 closed, the gas from the sterilization tank 2 can be discharged through the catalytic reactor 6 through the first exhaust passage 9a. Conversely, if the bypass valve 12 is opened while the inlet valve 10 and the outlet valve 11 are closed, the gas from the sterilization tank 2 can be discharged through the second exhaust passage 9b without passing through the catalyst reactor 6. it can.

  The catalytic reactor 6 includes a catalyst that decomposes formaldehyde. Specifically, a catalyst is provided in a reaction vessel through which gas from the sterilization tank 2 is passed. As the catalyst, various conventionally known ones such as a mesh material carrying platinum or palladium can be used. The catalyst reactor 6 includes a heater (not shown), and the catalyst heats the catalyst to a set temperature (200 to 250 ° C. in this embodiment). In this case, as will be described in detail later, it is preferable not to directly heat the catalyst itself (or the gas itself from the sterilization tank 2) but to heat it from the outside of the reaction vessel. Further, in order to effectively perform the decomposition reaction with the catalyst, air from the outside may be mixed into the gas from the sterilization tank 2 and passed through the catalyst reactor 6 as desired.

  The water vapor and formaldehyde gas introduction means 4 includes a water tank 13, a formalin tank 14, and a vaporizer 15. The water tank 13 is a tank in which water is stored, and the formalin tank 14 is a tank in which formalin is stored. Note that formalin is an aqueous formaldehyde solution having a predetermined concentration (formaldehyde concentration of 2 to 37% in this embodiment).

  The water tank 13 and the formalin tank 14 are connected to the vaporizer 15 via the liquid supply path 16 (16a, 16b). In the illustrated example, the first liquid supply path 16a from the water tank 13 to the vaporizer 15 and the second liquid supply path 16b from the formalin tank 14 to the vaporizer 15 are a common line on the vaporizer 15 side. Has been. A first liquid supply valve 17 is provided in the first liquid supply path 16a and a second liquid supply valve is provided in the second liquid supply path 16b on the upstream side (the tanks 13 and 14 side) of the common pipe. 18 is provided. However, in some cases, a liquid supply pump may be provided in place of the liquid supply valves 17 and 18.

  The vaporizer 15 is connected to the water tank 13 and the formalin tank 14 via the liquid supply path 16 (16a, 16b), and is connected to the sterilization tank 2 via the communication path 19. The vaporizer 15 includes a heater (not shown), and the inside of the vaporizer 15 is heated to a predetermined temperature by the heater. When the first liquid supply valve 17 is opened with the second liquid supply valve 18 closed while the heater of the vaporizer 15 is operated and the inside of the sterilization tank 2 is decompressed, water from the water tank 13 is supplied to the vaporizer 15. It can be introduced and vaporized, and can be supplied into the sterilization tank 2 through the communication passage 19 as water vapor. Alternatively, when the second liquid supply valve 18 is opened while the first liquid supply valve 17 is closed, formalin from the formalin tank 14 is introduced into the vaporizer 15 to be vaporized and sterilized as formaldehyde-containing water vapor via the communication passage 19. It can be supplied into the tank 2.

  In the present specification, formaldehyde-containing water vapor is sometimes simply referred to as formaldehyde gas in the sense that it contains at least formaldehyde gas. In other words, the formaldehyde gas is a gas containing at least formaldehyde, and in this embodiment, it is water vapor containing formaldehyde at a predetermined concentration.

  The outside air introduction means 5 introduces outside air into the sterilization tank 2 under reduced pressure via the air supply path 20. An air filter 21 and an air supply valve 22 are provided in the air supply path 20 into the sterilization tank 2. When the air supply valve 22 is opened while the inside of the sterilization tank 2 is decompressed, the outside air can be introduced into the sterilization tank 2 by the differential pressure inside and outside the sterilization tank 2 and the inside of the sterilization tank 2 can be decompressed. At that time, clean air can be introduced into the sterilization tank 2 by the air filter 21.

  The control means is a controller (not shown) that controls the vacuum pump 3 and the valves based on the detection signals of the sensors 7 and 8 and the elapsed time. Specifically, in addition to the vacuum pump 3, the inlet valve 10, the outlet valve 11, the bypass valve 12, the first liquid supply valve 17, the second liquid supply valve 18, the air supply valve 22, the pressure sensor 7 and the temperature sensor 8, The heaters of the sterilization tank 2, the catalytic reactor 6 and the vaporizer 15 are connected to a controller. Then, as will be described below, the controller attempts to sterilize the sterilized material in the sterilization tank 2 according to a predetermined procedure (program).

  Hereinafter, the specific example of the operating method of the low temperature steam formaldehyde sterilizer 1 of a present Example is demonstrated.

  FIG. 2 is a schematic diagram illustrating an example of an operation process of the low-temperature steam formaldehyde sterilizer 1 according to the present embodiment, and shows a relationship between the pressure P in the sterilization tank 2 and the elapsed time t. As shown in this figure, the low-temperature steam formaldehyde sterilization apparatus 1 of the present embodiment includes a evacuation process S1, a steam replacement process S2, a gas replacement process S3, a sterilization process S4, a steam desorption process S5, and an air desorption process S6. Run sequentially. Hereinafter, each step will be described.

  Prior to the start of operation, the sterilization tank 2 contains sterilized material, and the door of the sterilization tank 2 is closed in an airtight manner. During each step, the sterilization tank 2 is heated and maintained at a set temperature (typically 55 to 80 ° C., preferably 50 to 60 ° C., 55 ° C. in this embodiment) by a heater. Further, the catalyst reactor 6 is heated to a set temperature (200 to 250 ° C. in this embodiment) by the heater before the start of the gas replacement step S3 at the latest. Then, when the user is instructed to start operation by pressing the start button or the like, the above steps are sequentially executed.

≪Evacuation process S1≫
In the evacuation step S1, the inside of the sterilization tank 2 is depressurized by the vacuum pump 3 until a predetermined end condition is satisfied. Specifically, with the inlet valve 10 and the outlet valve 11 closed, the bypass valve 12 is opened and the vacuum pump 3 is continuously operated. At this time, the liquid supply valves 17 and 18 and the air supply valve 22 are closed. Thereby, the gas in the sterilization tank 2 can be sucked and discharged outside, and the inside of the sterilization tank 2 can be decompressed. The evacuation step S1 is performed only for the set evacuation time in this embodiment. This time is preferably a time sufficient for confirming the capacity limit of the vacuum pump 3 (that is, how far the inside of the sterilization tank 2 can be depressurized). After the set evacuation time has elapsed, the bypass valve 12 is closed and the vacuum pump 3 is stopped, and the process proceeds to the next step.

  However, in the evacuation step S1, the inside of the sterilization tank 2 may be depressurized to the target evacuation pressure. In this case, the evacuation step S1 ends when the target evacuation pressure is reached, but within the set evacuation time. If the target evacuation pressure cannot be reached, the process should be terminated after the set evacuation time has elapsed. Meanwhile, the minimum pressure P1 reached is monitored by the pressure sensor 7. In any case, a pressure reduction target pressure PL for each step to be described later is set above the minimum pressure P1 reached in the vacuuming step S1. In addition, the pressure reduction target pressure PL of each process is typically set to less than 10 kPa (for example, about 4 to 9 kPa), and preferably set to 5 kPa or less. Then, the return pressure target pressure PU is set so as to exceed the pressure reduction target pressure PL and not more than the atmospheric pressure P0.

≪Steam replacement process S2≫
In the steam replacement step S2, the decompression in the sterilization tank 2 and the return pressure due to the introduction of water vapor are repeated a set number of times. Specifically, the depressurization to the depressurization target pressure PL by the vacuum pump 3 and the depressurization to the depressurization target pressure PU by the introduction of water vapor are repeated a set number of times. The first decompression can be omitted as the decompression in the evacuation step S1. Therefore, in the steam replacement step S2, after the pressure reduction in the evacuation step S1, the return pressure to the return pressure target pressure PU and the pressure reduction to the pressure reduction target pressure PL are repeated a set number of times.

  The set number of times can be defined as the number of times of return from the reduced pressure state (the number of pulses protruding upward in the pressure wave that swings up and down in FIG. 2). In the present embodiment, when the pressure reduction is repeated, the pressure reduction target pressures PL of the respective times are the same, and the pressure reduction target pressures PU of the respective times are also the same. The same applies not only to the steam replacement step S2, but also to the gas replacement step S3, the vapor desorption step S5, and the air desorption step S6.

  The repetition of the depressurization pressure in the steam replacement step S2 will be described in detail. First, at the time of depressurization in the sterilization tank 2, the bypass valve 10 and the outlet valve 11 are closed with the inlet valve 10 and the outlet valve 11 closed as in the evacuation step S1. The valve 12 is opened and the vacuum pump 3 is activated. When the pressure detected by the pressure sensor 7 reaches the pressure reduction target pressure PL, the bypass valve 12 is closed and the vacuum pump 3 is stopped. Thereafter, when the first liquid supply valve 17 is opened, water in the water tank 13 is sucked into the vaporizer 15, and water vapor evaporated in the vaporizer 15 is introduced into the sterilization tank 2. When the inside of the sterilization tank 2 reaches the return pressure target pressure PU, the first liquid supply valve 17 is closed. Then, the repetition of such pressure reduction and return pressure is executed a set number of times.

  However, as shown in the figure, after steam is introduced into the sterilization tank 2 to return to the return pressure target pressure PU, it may be held at the return pressure target pressure PU for a set holding time (for example, 30 seconds). The return pressure in the sterilization tank 2 may not be until the detected pressure of the pressure sensor 7 reaches the return pressure target pressure PU, but until the set release time elapses from the opening of the first liquid supply valve 17. In any case, in the steam replacement step S2, air is removed from the sterilization tank 2 and replaced with water vapor by repeating the decompression in the sterilization tank 2 and the return pressure due to the introduction of water vapor.

≪Gas replacement step S3≫
In the gas replacement step S3, the depressurization in the sterilization tank 2 and the return pressure by introducing formaldehyde gas are repeated a set number of times. Specifically, the depressurization to the depressurization target pressure PL by the vacuum pump 3 and the depressurization to the depressurization target pressure PU by introducing formaldehyde gas are repeated a set number of times. The first decompression can be omitted as the final decompression in the steam replacement step S2. Therefore, in the gas replacement step S3, after the completion of the steam replacement step S2, the return pressure to the return pressure target pressure PU and the pressure reduction to the pressure reduction target pressure PL are repeated a set number of times.

  Note that both the steam replacement step S2 and the gas replacement step S3 are steps in which the pressure reduction to the pressure reduction target pressure PL and the pressure reduction to the return pressure target pressure PU are repeated a set number of times. The number of times may be different from each other. Similarly, the pressure reduction target pressures PL in both steps may be different from each other, and the pressure reduction target pressures PU in both steps may be different from each other. These are not limited to the relationship between the steam replacement step S2 and the gas replacement step S3, and the same applies to the processes including the steam desorption step S5 and the air desorption step S6. The same applies to the holding time (set holding time) at the return pressure target pressure PU. In the illustrated example, in the vapor replacement step S2, the gas replacement step S3, the vapor desorption step S5, and the air desorption step S6, the pressure reduction target pressures PL of the respective steps are the same, except for the air desorption step S6, The return pressure target pressures PU in the process are also the same.

  The repetition of the reduction pressure in the gas replacement step S3 will be specifically described. First, when the pressure in the sterilization tank 2 is reduced, the inlet valve 10 and the outlet valve 11 are opened with the bypass valve 12 closed, and the vacuum pump 3 is activated. Thereby, the gas in the sterilization tank 2 is discharged through the catalytic reactor 6, and the formaldehyde contained in the exhaust gas is decomposed and rendered harmless by the catalyst. When the pressure detected by the pressure sensor 7 reaches the target pressure PL, the inlet valve 10 and the outlet valve 11 are closed and the vacuum pump 3 is stopped. Thereafter, when the second liquid supply valve 18 is opened, the formalin in the formalin tank 14 is sucked into the vaporizer 15, and formaldehyde gas evaporated in the vaporizer 15 (strictly, as described above, formaldehyde-containing water vapor) It is introduced in. When the inside of the sterilization tank 2 reaches the return pressure target pressure PU, the second liquid supply valve 18 is closed. Then, the repetition of such pressure reduction and return pressure is executed a set number of times.

  However, as shown in the illustrated example, after formaldehyde gas is introduced into the sterilization tank 2 and the pressure is restored to the return pressure target pressure PU, the set pressure may be held for a set holding time (for example, 30 seconds). . Further, the return pressure in the sterilization tank 2 may not be until the detected pressure of the pressure sensor 7 reaches the return pressure target pressure PU but until the set release time elapses from the opening of the second liquid supply valve 18. In any case, the water vapor in the sterilization tank 2 is replaced with formaldehyde gas by repeating the decompression in the sterilization tank 2 and the return pressure by introducing formaldehyde gas in the gas replacement step S3. In other words, the sterilization tank 2 is filled with formaldehyde gas having a concentration corresponding to that in the formalin tank 14.

≪Sterilization step S4≫
In the sterilization step S4, the inside of the sterilization tank 2 is held at the sterilization temperature for the sterilization time. Here, the sterilization tank is maintained while the sterilization tank 2 is maintained at the sterilization pressure (PU in the illustrated example) at the final repressure in the gas replacement step S3 (return pressure by introducing formaldehyde gas into the sterilization tank 2). The inside of 2 is kept at sterilization temperature for sterilization time.

  Specifically, in the sterilization step S4, the introduction of formaldehyde gas into the sterilization tank 2 (more specifically, the second liquid supply) so that the temperature detected by the temperature sensor 8 maintains the sterilization temperature (eg, 55 ° C.). By controlling the valve 18) and maintaining the sterilization time (for example, 60 minutes), the sterilized material in the sterilization tank 2 is sterilized. Alternatively, the introduction of formaldehyde gas into the sterilization tank 2 is controlled so as to maintain the sterilization time so that the detected pressure of the pressure sensor 7 maintains the sterilization pressure (saturated steam pressure corresponding to the sterilization temperature). Sterilize the sterilized material in 2. Thereafter, the process proceeds to the next step with the second liquid supply valve 18 closed.

≪Vapor desorption process S5≫
In the vapor desorption process S5, the depressurization in the sterilization tank 2 and the return pressure due to the introduction of water vapor are repeated a set number of times. Specifically, the depressurization to the depressurization target pressure PL by the vacuum pump 3 and the depressurization to the depressurization target pressure PU by the introduction of water vapor are repeated a set number of times.

  The repetition of the depressurization pressure in the vapor desorption step S5 will be specifically described. First, when the pressure in the sterilization tank 2 is reduced, the inlet valve 10 and the outlet valve 11 are opened with the bypass valve 12 closed, and the vacuum is released. The pump 3 is activated. Thereby, the gas in the sterilization tank 2 is discharged via the catalytic reactor 6, and the formaldehyde contained in the exhaust gas is rendered harmless by the catalyst. When the pressure detected by the pressure sensor 7 reaches the target pressure PL, the inlet valve 10 and the outlet valve 11 are closed and the vacuum pump 3 is stopped. Thereafter, when the first liquid supply valve 17 is opened, water in the water tank 13 is sucked into the vaporizer 15, and water vapor evaporated in the vaporizer 15 is introduced into the sterilization tank 2. When the inside of the sterilization tank 2 reaches the return pressure target pressure PU, the first liquid supply valve 17 is closed. Then, the repetition of such pressure reduction and return pressure is executed a set number of times.

  However, as shown in the illustrated example, after introducing water vapor into the sterilization tank 2 and returning the pressure to the return pressure target pressure PU, the set retention time (in the illustrated example, the steam replacement step S2 and the gas replacement step) is reached. It may be held only for a time shorter than the set holding time in S3. The return pressure in the sterilization tank 2 may not be until the detected pressure of the pressure sensor 7 reaches the return pressure target pressure PU, but until the set release time elapses from the opening of the first liquid supply valve 17. In any case, in the vapor desorption step S5, by repeatedly reducing the pressure in the sterilization tank 2 and returning the pressure by introducing water vapor, the formaldehyde in the sterilization tank 2 is eliminated and replaced with water vapor containing no formaldehyde.

≪Air desorption process S6≫
In the air detaching step S6, the decompression in the sterilization tank 2 and the return pressure by introducing air are repeated a set number of times. Specifically, the depressurization up to the depressurization target pressure PL by the vacuum pump 3 and the depressurization up to the decompression target pressure PU by introducing air are repeated a set number of times. The first decompression can be omitted as the final decompression in the vapor desorption step S5. Therefore, in the air desorption process S6, after the completion of the vapor desorption process S5, the return pressure to the return pressure target pressure PU and the pressure reduction to the pressure reduction target pressure PL are repeated a set number of times.

  In this embodiment, the pressure reduction target pressure PL in the air desorption process S6 is the same as the pressure reduction target pressure PL in the steam replacement process S2, the gas replacement process S3, and the steam desorption process S5. On the other hand, the return pressure target pressure PU in the air desorption process S6 is preferably set higher than the return pressure target pressures PU in the steam replacement process S2, the gas replacement process S3, and the steam desorption process S5. The pressure should be close to that.

  The repetition of the depressurization pressure in the air detaching step S6 will be specifically described. First, when the pressure in the sterilization tank 2 is reduced, the bypass valve 12 is opened with the inlet valve 10 and the outlet valve 11 closed, and the vacuum is reduced. The pump 3 is activated. When the pressure detected by the pressure sensor 7 reaches the pressure reduction target pressure PL, the bypass valve 12 is closed and the vacuum pump 3 is stopped. Thereafter, when the air supply valve 22 is opened, outside air is introduced into the sterilization tank 2. When the inside of the sterilization tank 2 reaches the return pressure target pressure PU, the air supply valve 22 is closed. Then, the repetition of such pressure reduction and return pressure is executed a set number of times.

  However, when the pressure in the sterilization tank 2 is reduced, the gas from the sterilization tank 2 may be passed through the catalytic reactor 6. That is, when the pressure in the sterilization tank 2 is reduced, the vacuum valve 3 may be operated by opening the inlet valve 10 and the outlet valve 11 with the bypass valve 12 closed. Thereby, since the gas in the sterilization tank 2 is discharged through the catalytic reactor 6, even if formaldehyde remains in the sterilization tank 2, the formaldehyde is rendered harmless by the catalyst. When the pressure detected by the pressure sensor 7 reaches the target pressure PL, the inlet valve 10 and the outlet valve 11 are closed, the vacuum pump 3 is stopped, and the air supply valve 22 is opened.

  In any case, in the air detachment step S6, by repeating the decompression in the sterilization tank 2 and the return pressure by introducing air, the steam is removed from the sterilization tank 2 and replaced with air. Finally, with the vacuum pump 3 stopped, the air supply valve 22 is opened, and the inside of the sterilization tank 2 is restored to atmospheric pressure. Thereafter, the door of the sterilization tank 2 is opened, and the sterilized product can be taken out from the sterilization tank 2.

  According to the low temperature steam formaldehyde sterilization apparatus 1 of the present embodiment, the formaldehyde contained in the exhaust gas can be decomposed by passing the exhaust gas from the sterilization tank 2 to the vacuum pump 3 through the catalytic reactor 6. Thereby, the inflow of formaldehyde into the vacuum pump 3 can be prevented, and the penetration of formaldehyde into the sealing water and consequently the waste water can be prevented. Further, a large amount of water for diluting formaldehyde is not required, and the running cost can be reduced.

  In addition, it is possible to switch whether or not the exhaust from the sterilization tank 2 is passed through the catalytic reactor 6. Therefore, according to the gas in the sterilization tank 2 (in other words, according to the operation process), it is possible to switch whether or not the exhaust gas from the sterilization tank 2 is passed through the catalytic reactor 6. When exhausting through the catalytic reactor 6, formaldehyde can be decomposed in the catalytic reactor 6, and when exhausting through the catalytic reactor 6, the pressure loss is reduced by the amount not passing through the catalytic reactor 6. Thus, the exhaust time can be shortened. At least in the gas replacement step S3 and the vapor desorption step S5 in which formaldehyde is contained in the exhaust from the sterilization tank 2, the gas from the sterilization tank 2 is preferably exhausted through the catalyst reactor 6. In the air detachment step S6, even when formaldehyde remains in the sterilization tank 2, it is made harmless by exhausting it through the catalytic reactor 6 when evacuating from the sterilization tank 2. Can be exhausted.

  FIG. 3 is a schematic view showing a modified example of the low-temperature steam formaldehyde sterilizer 1 of the embodiment. This modification (FIG. 3) is also basically the same as the embodiment (FIG. 1). Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  This modification is different from the previous embodiment in the configuration of the exhaust system from the sterilization tank 2 to the vacuum pump 3. This will be specifically described below. First, the exhaust path 9 from the inside of the sterilization tank 2 branches into the first exhaust path 9a and the second exhaust path 9b, and then merges again and is connected to the vacuum pump 3 as in the above embodiment. However, the first exhaust path 9a is provided with an inlet valve 10, a catalytic reactor 6, a communication valve 23, a tank 24, and an outlet valve 11 in this order. On the other hand, a bypass valve 12 is provided in the second exhaust passage 9b as in the above embodiment. As will be described later, by controlling the opening / closing of the valves 10, 11, 12, and 23, it is possible to switch between exhausting through the first exhaust passage 9a and exhausting through the second exhaust passage 9b. .

  In addition to the catalyst reactor 6, the configurations of the inlet valve 10, the outlet valve 11 and the bypass valve 12 are the same as in the above embodiment. The tank 24 is a hollow container smaller than the sterilization tank 2 and is heated to a set temperature (for example, 55 ° C., which is the same as the heating temperature in the sterilization tank 2) by a heater (for example, heat tape). The tank 24 is connected to the catalytic reactor 6 through the communication valve 23 and is connected to the vacuum pump 3 through the outlet valve 11.

  In order to exhaust air through the first exhaust passage 9a, the outlet valve 11 is opened with the bypass valve 12 closed and the inlet valve 10 and the communication valve 23 are closed. The inside of 24 is depressurized to a predetermined pressure (first operation). This predetermined pressure is a pressure lower than the pressure in the sterilization tank 2. Thereafter, with the outlet valve 11 closed, the inlet valve 10 and the communication valve 23 are opened, and the inside of the sterilization tank 2 is depressurized (second operation). That is, the gas in the sterilization tank 2 is sucked into the tank 24 through the catalyst reactor 6 by communicating the inside of the sterilization tank 2 and the tank 24 through the catalyst reactor 6. At that time, formaldehyde contained in the exhaust gas from the sterilization tank 2 is decomposed and rendered harmless by the catalyst. Thereafter, with the inlet valve 10 and the communication valve 23 closed again, the outlet valve 11 is opened to decompress the tank 24 (third operation). As a result, the water vapor remaining in the tank 24 can be eliminated, and the pressure in the tank 24 can be reduced to a predetermined pressure again.

  When exhausting the gas containing formaldehyde from the sterilization tank 2, it is preferable to exhaust the gas via the first exhaust path 9a by performing the third operation from the first operation described above. For example, in the gas replacement step S3 and the vapor desorption step S5, as described in the above embodiment, the decompression and the decompression are repeated a set number of times, and each decompression is performed from the first operation to the third operation. Should be done in one set of implementations. That is, it is preferable to set the inside of the tank 24 to a predetermined pressure lower than the pressure reduction target pressure PL by the first operation and to reduce the pressure in the sterilization tank 2 to the pressure reduction target pressure PL by the second operation. Considering this point, the capacity of the tank 24 and the pressure reduction level (by the first operation) are set.

  The pressure reduction (first operation) in the tank 24 can be performed in advance (that is, before the start of the process) in the gas replacement step S3, for example, or during the decompression by introducing formaldehyde gas into the sterilization tank 2 after the pressure reduction. In addition to the vapor desorption step S5, it can be performed in advance (that is, before the start of the process), and in parallel during the decompression by introducing water vapor into the sterilization tank 2 after decompression. be able to.

  On the other hand, in order to exhaust through the second exhaust path 9b, the bypass valve 12 is opened and the vacuum pump 3 is exhausted with the inlet valve 10 and the outlet valve 11 closed as in the above embodiment. Good. Other configurations and operation methods are the same as those in the above embodiment, and thus the description thereof is omitted.

  Next, a specific example of the catalytic reactor 6 used in the low-temperature steam formaldehyde sterilizer 1 of the embodiment (including the modified example) will be described. As described above, the catalytic reactor 6 includes a reaction vessel, a catalyst, and a heater.

  The reaction container is a container through which gas from the sterilization tank 2 is passed, and is typically formed from a cylindrical material such as a cylinder or a rectangular tube. A catalyst for decomposing formaldehyde is provided in the reaction vessel. Typically, the cylindrical reaction vessel is provided with a catalyst in the middle in the axial direction, and gas from the sterilization tank 2 to the vacuum pump 3 passes from one opening to the other opening. Is done.

  The reaction vessel is provided with a heater, and the catalyst is heated by this heater. For example, a mantle heater is provided so as to cover the entire peripheral side wall of the reaction vessel from the outside. Before the gas from the sterilization tank 2 is passed through the catalyst, the heater heats the catalyst to a set temperature (150 ° C. or higher, preferably 200 to 250 ° C.) by the heater, and then maintains the set temperature. Is controlled. In addition, while the gas containing formaldehyde passes through the catalyst, the temperature of the catalyst becomes higher than the set temperature, but is suppressed to be lower than the spontaneous ignition temperature of formaldehyde.

  By the way, it is preferable that the heater not only warms the catalyst but also warms a gas (for example, a gas of 50 to 55 ° C.) from the sterilization tank 2 to the catalyst. That is, the gas from the sterilization tank 2 is preferably heated in the reaction container so that the set temperature is 150 ° C. or more immediately before the catalyst. In order to realize this easily and compactly, the catalytic reactor 6 is preferably configured as follows.

  FIG. 4 is a schematic cross-sectional view showing an example of the catalytic reactor 6. In this example, the catalytic reactor 6 has a double tube structure including an inner cylinder 25 and an outer cylinder 26, and a catalyst 27 is provided in the inner cylinder 25, while the outer cylinder 26 is added by a heater (not shown). Be warmed. The gas from the inside of the sterilization tank 2 passes through the gap between the inner cylinder 25 and the outer cylinder 26, and then turns back and passes through the inner cylinder 25.

  More specifically, the inner cylinder 25 is accommodated in the outer cylinder 26 with the axes aligned. The inner cylinder 25 and the outer cylinder 26 each have a fluid inlet / outlet at one axial end (right end in FIG. 4) and are closed by an end wall 28 at the other axial end (left end in FIG. 4). That is, the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 is closed by the end wall 28 at the other axial end, and the hollow hole of the inner cylinder 25 is also closed by the same end wall 28. A plurality of communication portions (through holes or notches) 29 are formed on the peripheral side wall of the inner cylinder 25 at positions close to the end wall 28 and spaced apart in the circumferential direction. The inside and outside of the inner cylinder 25 communicate with each other. That is, the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 and the hollow hole of the inner cylinder 25 communicate with each other via the communication portion 29 provided on the peripheral side wall of the inner cylinder 25.

  On the other hand, at one end in the axial direction, the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 is connected to the pipe from the sterilization tank 2, and the hollow hole of the inner cylinder 25 is connected to the pipe to the vacuum pump 3. Is done. In the illustrated example, an end wall 30 is also provided at one end in the axial direction, and this end wall 30 closes the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 and the hollow hole of the inner cylinder 25. It is done. However, through holes 30a and 30b are formed in the end wall 30 at positions corresponding to the cylindrical gaps and the hollow holes, respectively. Then, piping from the sterilization tank 2 and piping to the vacuum pump 3 are connected to the pipe portions provided in the through holes 30a and 30b. In addition, a catalyst 27 is provided in the central portion of the inner cylinder 25 in the axial direction.

  Further, the outer cylinder 26 of the catalyst reactor 6 is provided with a heater (not shown). For example, in addition to the peripheral side wall of the outer cylinder 26, a mantle heater is preferably provided so as to cover the end walls 28 and 30 (at least the end wall 28 at the other end in the axial direction). By operating this heater, the inside of the outer cylinder 26, that is, the inside of the inner cylinder 25 and the catalyst 27 can be heated to the set temperature.

  When the gas in the sterilization tank 2 is discharged by the vacuum pump 3 via the catalyst reactor 6, the catalyst 27 is heated to a set temperature in advance with a heater. Since the reaction vessel (25, 26) has a double-pipe structure, it is difficult to heat the catalyst as compared with the case of a single pipe (only the inner cylinder 25). In the evacuation step S1 and the steam replacement step S2, since the exhaust is performed through the second exhaust passage 9b (that is, not through the catalyst reactor 6), it is possible to secure a time for heating the catalyst 27 with a heater during that time. it can.

By the way, the decomposition reaction of formaldehyde requires oxygen as shown by the reaction formula “HCHO + O ₂ → CO ₂ + H ₂ O”. However, as described in the above embodiment, after the air is removed from the sterilization tank 2 in the evacuation process S1 and the steam replacement process S2, formaldehyde gas is introduced into the sterilization tank 2 (gas replacement process). S3) Sterilization is achieved under vacuum. Therefore, even when formaldehyde is passed through the catalytic reactor 6 during exhaust from the sterilization tank 2, there is a risk that the expected decomposition is not performed due to lack of oxygen. Therefore, it is preferable that the gas from the inside of the sterilization tank 2 is passed through the catalytic reactor 6 after air from outside is mixed therein.

  In the illustrated example, an air hole 30c is formed in the end wall 30 at one end in the axial direction (a position communicating with the cylindrical gap) as an outside air intake. Therefore, when evacuation is performed, air from outside is automatically drawn into the gas from the inside of the sterilization tank 2, and after the gap between the inner cylinder 25 and the outer cylinder 26 is passed, Passed through catalyst 27. In the meantime, mixing of the gas from the inside of the sterilization tank 2 and the air from the outside and heating by a heater are performed. Moreover, excessive temperature rise in the catalyst 27 can also be suppressed by diluting the formaldehyde gas from the sterilization tank 2 with air.

  Furthermore, a valve may be provided in a pipe line to the air hole 30c so that the opening / closing or opening degree of the valve can be adjusted. In addition, the air hole 30c is not limited to the end wall 30 at one end in the axial direction, and may be formed in the outer cylinder 26. In some cases, the air hole 30c may be formed in a pipe from the sterilization tank 2 to the catalyst reactor 6. . In any case, the formaldehyde can be reliably decomposed by mixing air into the gas from the sterilization tank 2 and passing it through the catalytic reactor 6.

  Note that the posture of the catalyst reactor 6 is not limited to the horizontal direction, and may be the vertical direction or the diagonal direction. That is, in FIG. 4, the catalytic reactor 6 has the inner cylinder 25 and the outer cylinder 26 arranged in the left-right direction, but is arranged in the up-down direction or diagonally. Also good. In the case of arranging vertically or obliquely, any of the pair of end walls 28 and 30 may be directed upward. Since the fluid passed through the catalyst reactor 6 is basically only gas, the posture and installation direction of the catalyst reactor 6 can be changed as appropriate. Moreover, although the inner cylinder 25 and the outer cylinder 26 were comprised from the cylinder in the example of illustration, you may be comprised from square cylinders, such as a cross-sectional square, depending on the case.

  FIG. 5 is a schematic cross-sectional view showing another example of the catalytic reactor 6. The catalytic reactor 6 in FIG. 5 is basically the same as the catalytic reactor 6 in FIG. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the catalytic reactor 6 of FIG. 4, the opening at the other axial end of the inner cylinder 25 and the outer cylinder 26 (left end in FIG. 4) is closed by the end wall 28, and the other axial end of the inner cylinder 25 is also closed. Although the communication part 29 was provided in the surrounding side wall, and the inside and outside of the inner cylinder 25 were connected, in the catalyst reactor 6 of FIG. 5, although the opening part of the axial direction other end part of the outer cylinder 26 is closed by the end wall 28, The other end of the inner cylinder 25 in the axial direction is spaced apart from the end wall 28 and has a gap. The gap (the gap between the other axial end portion of the inner cylinder 25 and the end wall 28) functions as a communication portion 29 that communicates the inside and the outside of the inner cylinder 25. Also in this case, the gas flowing from the one axial end to the other axial end through the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 is folded back at the other axial end and enters the inner cylinder 25 in the axial direction. It flows toward one end and is led out through a catalyst 27 in the inner cylinder 25. Other configurations are the same as those in FIG.

  The low-temperature steam formaldehyde sterilization apparatus 1 of the present invention is not limited to the configuration (including control) of the above-described embodiment (including modifications), and can be changed as appropriate. In particular, (a) a sterilization tank 2 in which sterilized materials are stored, (b) a water-sealed vacuum pump 3 for sucking and discharging the gas in the sterilization tank 2 to the outside, and (c) a vacuum pump from the sterilization tank 2 As long as it is provided with the catalytic reactor 6 that decomposes formaldehyde and is provided in the exhaust passage 9 to 3, the other configurations can be appropriately changed.

  For example, in the embodiment, the exhaust through the first exhaust passage 9a and the exhaust through the second exhaust passage 9b are performed by switching the inlet valve 10, the outlet valve 11 and the bypass valve 12. The specific configuration whether or not to pass through the catalyst reactor 6 is not particularly limited. As an example, instead of the inlet valve 10 and the bypass valve 12, a three-way valve may be provided at a branch portion between the first exhaust path 9 a and the second exhaust path 9 b, or instead of the outlet valve 11 and the bypass valve 12. A three-way valve may be provided at the junction of the first exhaust passage 9a and the second exhaust passage 9b.

  Moreover, in the said Example, the bypass valve 12 of the 2nd exhaust passage 9b can be abbreviate | omitted by the case. Alternatively, the installation of the second exhaust path 9b itself may be omitted. That is, the exhaust from the sterilization tank 2 may always be discharged by the vacuum pump 3 via the catalytic reactor 6. In that case, installation of the outlet valve 11 can be omitted in addition to the second exhaust passage 9b.

  In the above embodiment, the evacuation step S1, the vapor replacement step S2, the gas replacement step S3, the sterilization step S4, the vapor desorption step S5, and the air desorption step S6 are sequentially performed. , The presence / absence and content of each process can be changed as appropriate. For example, the evacuation step S1 can be used to check for leakage during decompression in the sterilization tank 2 (outflow of outside air into the sterilization tank 2) and to determine the number of times of decompression pressure in each subsequent process. However, when the leak check is not performed and the set number of times is fixed, the evacuation step S1 can be omitted. The steam replacement step S2 is intended to exclude air from the sterilization tank 2, but formaldehyde gas can be used instead of water vapor. Therefore, instead of not performing the steam replacement step S2, the number of times of reduced pressure in the gas replacement step S3 may be increased.

1 Low-temperature steam formaldehyde sterilizer 2 Sterilization tank 3 Vacuum pump (3a: intake port, 3b: exhaust port)
4 Introducing means for water vapor and formaldehyde gas 5 Introducing means for outside air 6 Catalytic reactor 7 Pressure sensor 8 Temperature sensor 9 Exhaust path (9a: first exhaust path, 9b: second exhaust path)
DESCRIPTION OF SYMBOLS 10 Inlet valve 11 Outlet valve 12 Bypass valve 13 Water tank 14 Formalin tank 15 Vaporizer 16 Supply path (16a: 1st supply path, 16b: 2nd supply path)
17 First supply valve 18 Second supply valve 19 Communication path 20 Supply path 21 Air filter 22 Supply valve 23 Communication valve 24 Tank 25 Inner cylinder 26 Outer cylinder 27 Catalyst 28 End wall 29 Communication section 30 End wall (30a : Through hole, 30b: Through hole, 30c: Air hole)
P0 Atmospheric pressure P1 Minimum pressure PL Depressurization target pressure PU Return pressure target pressure S1 Vacuum evacuation process S2 Steam replacement process S3 Gas replacement process S4 Sterilization process S5 Steam desorption process S6 Air desorption process

  The present invention relates to a low temperature steam formaldehyde (LTSF) sterilizer.

  Conventionally, as disclosed in Patent Document 1 below, a low-temperature steam formaldehyde sterilization apparatus that sterilizes a sterilized product with formaldehyde-containing water vapor in a sterilization tank under vacuum is known. In this apparatus, since water vapor is handled under vacuum, a water-sealed vacuum pump is preferably used instead of a dry type.

  When a water-sealed vacuum pump is used, formaldehyde dissolves in the sealed water, so even if diluted with a large amount of water, formaldehyde will spill out, which is not preferable from the viewpoint of environmental protection. In addition, when formaldehyde is diluted with a large amount of water, the amount of water used increases and the running cost increases. Although an environmental purification microreactor system disclosed in the following Patent Document 2 has also been proposed, it is basically applied to a sterilizer using ethylene oxide gas (or a mixed gas with carbon dioxide) and is water-sealed. The use of a vacuum pump is also denied (paragraphs [0003] and [0008] of Patent Document 2), and is not applicable to a low-temperature steam formaldehyde sterilizer.

JP 2014-233503 A (paragraphs [0002], [0026], [0036]) Japanese Patent Laying-Open No. 2005-254194 (FIG. 1)

  The problem to be solved by the present invention is to provide an environment-friendly device in a low-temperature steam formaldehyde sterilization apparatus using a water-sealed vacuum pump by preventing the formaldehyde from entering the sealed water and thus drainage. . It is another object of the present invention to provide a device that does not require a large amount of water for dilution and can reduce running costs.

  The present invention has been made to solve the above problems, and the invention according to claim 1 is a sterilization tank in which a sterilized material is stored, and a water-sealed type that sucks and discharges the gas in the sterilization tank to the outside. A low-temperature steam formaldehyde sterilization apparatus comprising: a vacuum pump; and a catalytic reactor provided in an exhaust path from the sterilization tank to the vacuum pump to decompose formaldehyde.

  According to the first aspect of the present invention, since the formaldehyde can be decomposed by providing the catalytic reactor in the exhaust path from the sterilization tank to the vacuum pump, the inflow of formaldehyde to the vacuum pump can be prevented. Thereby, it is possible to prevent the formaldehyde from entering into the sealing water of the vacuum pump and thus the waste water. Further, a large amount of water for diluting formaldehyde is not required, and the running cost can be reduced.

  According to a second aspect of the present invention, switching between whether the gas in the sterilization tank is discharged via the catalytic reactor or not via the catalytic reactor by changing the flow path of the exhaust passage. The low-temperature steam formaldehyde sterilizer according to claim 1, which is made possible.

  According to invention of Claim 2, when discharging | emitting the gas in a sterilization tank with a vacuum pump, it can switch whether it discharges | emits via a catalyst reactor or not via a catalyst reactor. When discharging through the catalytic reactor, formaldehyde can be decomposed in the catalytic reactor, and when discharging without passing through the catalytic reactor, the pressure loss is reduced by the amount not passing through the catalytic reactor, and the exhaust time Can be shortened.

  The invention according to claim 3 includes a gas replacement step of repeatedly reducing the pressure in the sterilization tank and a return pressure by introducing formaldehyde gas, a sterilization step of maintaining the sterilization tank at a sterilization temperature for a sterilization time, A desorption step of repeating the depressurization of the gas and a return pressure by the introduction of water vapor, and an air desorption step of repeating the depressurization in the sterilization tank and the return pressure by the introduction of air in sequence, 3. The low temperature steam formaldehyde sterilizer according to claim 2, wherein in the vapor desorption step, the gas in the sterilization tank is discharged through the catalytic reactor when the pressure in the sterilization tank is reduced. .

  According to the third aspect of the invention, pretreatment, sterilization, and post-treatment can be achieved by operating by sequentially including a gas replacement step, a sterilization step, a vapor desorption step, and an air desorption step. Further, at least in the gas replacement step and the vapor desorption step, formaldehyde can be decomposed and rendered harmless by passing the gas in the sterilization tank through the catalyst reactor during decompression in the sterilization tank.

According to a fourth aspect of the present invention, the exhaust path from the inside of the sterilization tank branches to the first exhaust path and the second exhaust path, and then merges again and is connected to the vacuum pump. the exhaust passage, and the catalytic reactor is provided, according to claim, characterized in that said first exhaust path or the exhaust through, and whether the exhaust is capable of switching over the second exhaust passage A low-temperature steam formaldehyde sterilizer according to claim 2 or claim 3.

The invention described in claim 5 is characterized in that the sterilization tank is provided with a pressure sensor for detecting the pressure in the sterilization tank and a temperature sensor for detecting the temperature in the sterilization tank. It is a low-temperature steam formaldehyde sterilizer of any one of 1-4.

The invention according to claim 6 is the low-temperature steam formaldehyde sterilizer according to any one of claims 1 to 5, further comprising outside air introduction means into the sterilization tank.

The invention according to claim 7 is characterized in that the outside air introducing means includes an air supply path, and an air filter and an air supply valve provided in the air supply path. Sterilizer.

The invention according to claim 8 is the low-temperature steam formaldehyde sterilizer according to any one of claims 1 to 7, further comprising means for introducing water vapor and formaldehyde gas.

The invention according to claim 9 is the low-temperature steam formaldehyde sterilizer according to claim 8, wherein the means for introducing the water vapor and formaldehyde gas includes a water tank, a formalin tank, and a vaporizer. .

The invention according to claim 10 is the low temperature steam formaldehyde sterilizer according to claim 9, wherein the vaporizer includes a heater.

According to an eleventh aspect of the present invention, the water tank and the formalin tank are connected to the vaporizer via a liquid supply path, and the vaporizer is connected to the sterilization tank via a communication path. The low-temperature steam formaldehyde sterilization apparatus according to claim 9 or 10, characterized in that

The present invention as described in claim 12, the gas from the sterilization chamber, after being mixed air from outside, one of the claims 1 to 11, characterized in that it is passed through the catalytic reactor 2. A low-temperature steam formaldehyde sterilizer according to claim 1.

Oxygen is required for the decomposition reaction of formaldehyde. However, if sterilization is performed under vacuum after the air is removed from the sterilization tank, oxygen will be insufficient even if formaldehyde is passed through the catalytic reactor during exhaustion from the sterilization tank. May cause the expected disassembly. However, according to the invention described in claim 12 , since air is mixed into the gas from the sterilization tank and passed through the catalytic reactor, it is possible to reliably decompose formaldehyde.

  According to the present invention, in a low-temperature steam formaldehyde sterilization apparatus using a water-sealed vacuum pump, it is possible to prevent the formaldehyde from infiltrating into the sealed water and thus to the wastewater, thereby making the environment friendly. In addition, a large amount of water for dilution is not required, and the running cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the low temperature steam formaldehyde sterilizer of one Example of this invention, and it has shown one part in cross section. It is the schematic which shows an example of the operation | movement process of the low temperature steam formaldehyde sterilizer of FIG. 1, and has shown the relationship between the pressure P in a sterilization tank, and the elapsed time t. It is a figure which shows the modification of the low temperature steam formaldehyde sterilizer of FIG. It is a schematic sectional drawing which shows an example of the catalytic reactor used for the low temperature steam formaldehyde sterilizer of FIG. It is a schematic sectional drawing which shows the other example of the catalytic reactor used for the low temperature steam formaldehyde sterilizer of FIG.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a low-temperature steam formaldehyde sterilization apparatus 1 according to an embodiment of the present invention, and a part thereof is shown in cross section.

  The low-temperature steam formaldehyde sterilization apparatus 1 of the present embodiment includes a sterilization tank 2 in which a sterilized material is stored, a water-sealed vacuum pump 3 that sucks and discharges the gas in the sterilization tank 2 to the outside, and the sterilization tank 2 Water vapor and formaldehyde gas introduction means 4, outside air introduction means 5 into the sterilization tank 2, catalytic reactor 6 for decomposing formaldehyde to the outside of the sterilization tank 2, and control means (not shown).

  The sterilized material is not particularly limited, but is typically a medical instrument such as forceps or a tube. The sterilized product may be accommodated in the sterilization tank 2 in a state of being put in a sterilization packaging material.

  The sterilization tank 2 is a hollow container that can withstand decompression of the internal space, and is typically formed in a substantially rectangular box shape. The sterilization tank 2 can be opened and closed by a door (not shown). By opening the door, sterilized materials can be taken in and out of the sterilization tank 2, and by closing the door, the sterilization tank 2 can be closed airtight.

  The inside of the sterilization tank 2 can be heated with a heater (not shown). The heater of the sterilization tank 2 is not particularly limited in its configuration, and may be, for example, a steam jacket. In the present embodiment, the heater is formed of a heat tape provided on the outer wall of the sterilization tank 2. The inside of the sterilization tank 2 can be maintained at a desired temperature by controlling on / off or capacity of the heater.

  The sterilization tank 2 is provided with a pressure sensor 7 for detecting the pressure in the sterilization tank 2 and a temperature sensor 8 for detecting the temperature in the sterilization tank 2. Although details will be described later, the decompression or return pressure in the sterilization tank 2 can be controlled based on the detected pressure of the pressure sensor 7, and the heater of the sterilization tank 2 can be controlled based on the detected temperature of the temperature sensor 8. it can.

  As is well known, the water-sealed vacuum pump 3 is operated while being supplied with water called sealed water. Specifically, in this embodiment, an impeller (not shown) having blades arranged radially is installed eccentrically with the casing in a cylindrical casing (reference numeral omitted) to which sealed water is supplied. . Therefore, when the impeller is rotated at a high speed, a water ring is formed in the casing, and the impeller and the casing are eccentric. Therefore, the internal gas repeats expansion and compression every time it rotates once. Therefore, by providing the intake port 3a and the exhaust port 3b at appropriate positions of the casing, it is possible to intake and exhaust external gas. The casing is further provided with a water supply port (not shown), and sealed water is supplied into the casing from the water supply port. A water supply valve (not shown) to the water supply port is opened and closed in conjunction with the start and stop of the vacuum pump 3. In addition, the used sealing water is also discharged | emitted from the exhaust port 3b.

  The suction port 3 a of the vacuum pump 3 is connected to the sterilization tank 2 through the exhaust path 9. A catalyst reactor 6 is provided in the exhaust path 9 from the sterilization tank 2 to the vacuum pump 3. At this time, preferably, the gas from the inside of the sterilization tank 2 can be switched between being discharged via the catalytic reactor 6 or discharged without going through the catalytic reactor 6. Specifically, the exhaust path 9 from the inside of the sterilization tank 2 branches into a first exhaust path 9a and a second exhaust path 9b, and then merges again and is connected to the vacuum pump 3. An inlet valve 10, a catalytic reactor 6 and an outlet valve 11 are provided in this order in the first exhaust passage 9a, and a bypass valve 12 is provided in the second exhaust passage 9b. Therefore, if the inlet valve 10 and the outlet valve 11 are opened with the bypass valve 12 closed, the gas from the sterilization tank 2 can be discharged through the catalytic reactor 6 through the first exhaust passage 9a. Conversely, if the bypass valve 12 is opened while the inlet valve 10 and the outlet valve 11 are closed, the gas from the sterilization tank 2 can be discharged through the second exhaust passage 9b without passing through the catalyst reactor 6. it can.

  The catalytic reactor 6 includes a catalyst that decomposes formaldehyde. Specifically, a catalyst is provided in a reaction vessel through which gas from the sterilization tank 2 is passed. As the catalyst, various conventionally known ones such as a mesh material carrying platinum or palladium can be used. The catalyst reactor 6 includes a heater (not shown), and the catalyst heats the catalyst to a set temperature (200 to 250 ° C. in this embodiment). In this case, as will be described in detail later, it is preferable not to directly heat the catalyst itself (or the gas itself from the sterilization tank 2) but to heat it from the outside of the reaction vessel. Further, in order to effectively perform the decomposition reaction with the catalyst, air from the outside may be mixed into the gas from the sterilization tank 2 and passed through the catalyst reactor 6 as desired.

  The water vapor and formaldehyde gas introduction means 4 includes a water tank 13, a formalin tank 14, and a vaporizer 15. The water tank 13 is a tank in which water is stored, and the formalin tank 14 is a tank in which formalin is stored. Note that formalin is an aqueous formaldehyde solution having a predetermined concentration (formaldehyde concentration of 2 to 37% in this embodiment).

  The water tank 13 and the formalin tank 14 are connected to the vaporizer 15 via the liquid supply path 16 (16a, 16b). In the illustrated example, the first liquid supply path 16a from the water tank 13 to the vaporizer 15 and the second liquid supply path 16b from the formalin tank 14 to the vaporizer 15 are a common line on the vaporizer 15 side. Has been. A first liquid supply valve 17 is provided in the first liquid supply path 16a and a second liquid supply valve is provided in the second liquid supply path 16b on the upstream side (the tanks 13 and 14 side) of the common pipe. 18 is provided. However, in some cases, a liquid supply pump may be provided in place of the liquid supply valves 17 and 18.

  The vaporizer 15 is connected to the water tank 13 and the formalin tank 14 via the liquid supply path 16 (16a, 16b), and is connected to the sterilization tank 2 via the communication path 19. The vaporizer 15 includes a heater (not shown), and the inside of the vaporizer 15 is heated to a predetermined temperature by the heater. When the first liquid supply valve 17 is opened with the second liquid supply valve 18 closed while the heater of the vaporizer 15 is operated and the inside of the sterilization tank 2 is decompressed, water from the water tank 13 is supplied to the vaporizer 15. It can be introduced and vaporized, and can be supplied into the sterilization tank 2 through the communication passage 19 as water vapor. Alternatively, when the second liquid supply valve 18 is opened while the first liquid supply valve 17 is closed, formalin from the formalin tank 14 is introduced into the vaporizer 15 to be vaporized and sterilized as formaldehyde-containing water vapor via the communication passage 19. It can be supplied into the tank 2.

  In the present specification, formaldehyde-containing water vapor is sometimes simply referred to as formaldehyde gas in the sense that it contains at least formaldehyde gas. In other words, the formaldehyde gas is a gas containing at least formaldehyde, and in this embodiment, it is water vapor containing formaldehyde at a predetermined concentration.

  The outside air introduction means 5 introduces outside air into the sterilization tank 2 under reduced pressure via the air supply path 20. An air filter 21 and an air supply valve 22 are provided in the air supply path 20 into the sterilization tank 2. When the air supply valve 22 is opened while the inside of the sterilization tank 2 is decompressed, the outside air can be introduced into the sterilization tank 2 by the differential pressure inside and outside the sterilization tank 2 and the inside of the sterilization tank 2 can be decompressed. At that time, clean air can be introduced into the sterilization tank 2 by the air filter 21.

  The control means is a controller (not shown) that controls the vacuum pump 3 and the valves based on the detection signals of the sensors 7 and 8 and the elapsed time. Specifically, in addition to the vacuum pump 3, the inlet valve 10, the outlet valve 11, the bypass valve 12, the first liquid supply valve 17, the second liquid supply valve 18, the air supply valve 22, the pressure sensor 7 and the temperature sensor 8, The heaters of the sterilization tank 2, the catalytic reactor 6 and the vaporizer 15 are connected to a controller. Then, as will be described below, the controller attempts to sterilize the sterilized material in the sterilization tank 2 according to a predetermined procedure (program).

  Hereinafter, the specific example of the operating method of the low temperature steam formaldehyde sterilizer 1 of a present Example is demonstrated.

  FIG. 2 is a schematic diagram illustrating an example of an operation process of the low-temperature steam formaldehyde sterilizer 1 according to the present embodiment, and shows a relationship between the pressure P in the sterilization tank 2 and the elapsed time t. As shown in this figure, the low-temperature steam formaldehyde sterilization apparatus 1 of the present embodiment includes a evacuation process S1, a steam replacement process S2, a gas replacement process S3, a sterilization process S4, a steam desorption process S5, and an air desorption process S6. Run sequentially. Hereinafter, each step will be described.

  Prior to the start of operation, the sterilization tank 2 contains sterilized material, and the door of the sterilization tank 2 is closed in an airtight manner. During each step, the sterilization tank 2 is heated and maintained at a set temperature (typically 55 to 80 ° C., preferably 50 to 60 ° C., 55 ° C. in this embodiment) by a heater. Further, the catalyst reactor 6 is heated to a set temperature (200 to 250 ° C. in this embodiment) by the heater before the start of the gas replacement step S3 at the latest. Then, when the user is instructed to start operation by pressing the start button or the like, the above steps are sequentially executed.

≪Evacuation process S1≫
In the evacuation step S1, the inside of the sterilization tank 2 is depressurized by the vacuum pump 3 until a predetermined end condition is satisfied. Specifically, with the inlet valve 10 and the outlet valve 11 closed, the bypass valve 12 is opened and the vacuum pump 3 is continuously operated. At this time, the liquid supply valves 17 and 18 and the air supply valve 22 are closed. Thereby, the gas in the sterilization tank 2 can be sucked and discharged outside, and the inside of the sterilization tank 2 can be decompressed. The evacuation step S1 is performed only for the set evacuation time in this embodiment. This time is preferably a time sufficient for confirming the capacity limit of the vacuum pump 3 (that is, how far the inside of the sterilization tank 2 can be depressurized). After the set evacuation time has elapsed, the bypass valve 12 is closed and the vacuum pump 3 is stopped, and the process proceeds to the next step.

  However, in the evacuation step S1, the inside of the sterilization tank 2 may be depressurized to the target evacuation pressure. In this case, the evacuation step S1 ends when the target evacuation pressure is reached, but within the set evacuation time. If the target evacuation pressure cannot be reached, the process should be terminated after the set evacuation time has elapsed. Meanwhile, the minimum pressure P1 reached is monitored by the pressure sensor 7. In any case, a pressure reduction target pressure PL for each step to be described later is set above the minimum pressure P1 reached in the vacuuming step S1. In addition, the pressure reduction target pressure PL of each process is typically set to less than 10 kPa (for example, about 4 to 9 kPa), and preferably set to 5 kPa or less. Then, the return pressure target pressure PU is set so as to exceed the pressure reduction target pressure PL and not more than the atmospheric pressure P0.

≪Steam replacement process S2≫
In the steam replacement step S2, the decompression in the sterilization tank 2 and the return pressure due to the introduction of water vapor are repeated a set number of times. Specifically, the depressurization to the depressurization target pressure PL by the vacuum pump 3 and the depressurization to the depressurization target pressure PU by the introduction of water vapor are repeated a set number of times. The first decompression can be omitted as the decompression in the evacuation step S1. Therefore, in the steam replacement step S2, after the pressure reduction in the evacuation step S1, the return pressure to the return pressure target pressure PU and the pressure reduction to the pressure reduction target pressure PL are repeated a set number of times.

  The set number of times can be defined as the number of times of return from the reduced pressure state (the number of pulses protruding upward in the pressure wave that swings up and down in FIG. 2). In the present embodiment, when the pressure reduction is repeated, the pressure reduction target pressures PL of the respective times are the same, and the pressure reduction target pressures PU of the respective times are also the same. The same applies not only to the steam replacement step S2, but also to the gas replacement step S3, the vapor desorption step S5, and the air desorption step S6.

  The repetition of the depressurization pressure in the steam replacement step S2 will be described in detail. First, at the time of depressurization in the sterilization tank 2, the bypass valve 10 and the outlet valve 11 are closed with the inlet valve 10 and the outlet valve 11 closed as in the evacuation step S1. The valve 12 is opened and the vacuum pump 3 is activated. When the pressure detected by the pressure sensor 7 reaches the pressure reduction target pressure PL, the bypass valve 12 is closed and the vacuum pump 3 is stopped. Thereafter, when the first liquid supply valve 17 is opened, water in the water tank 13 is sucked into the vaporizer 15, and water vapor evaporated in the vaporizer 15 is introduced into the sterilization tank 2. When the inside of the sterilization tank 2 reaches the return pressure target pressure PU, the first liquid supply valve 17 is closed. Then, the repetition of such pressure reduction and return pressure is executed a set number of times.

  However, as shown in the figure, after steam is introduced into the sterilization tank 2 to return to the return pressure target pressure PU, it may be held at the return pressure target pressure PU for a set holding time (for example, 30 seconds). The return pressure in the sterilization tank 2 may not be until the detected pressure of the pressure sensor 7 reaches the return pressure target pressure PU, but until the set release time elapses from the opening of the first liquid supply valve 17. In any case, in the steam replacement step S2, air is removed from the sterilization tank 2 and replaced with water vapor by repeating the decompression in the sterilization tank 2 and the return pressure due to the introduction of water vapor.

≪Gas replacement step S3≫
In the gas replacement step S3, the depressurization in the sterilization tank 2 and the return pressure by introducing formaldehyde gas are repeated a set number of times. Specifically, the depressurization to the depressurization target pressure PL by the vacuum pump 3 and the depressurization to the depressurization target pressure PU by introducing formaldehyde gas are repeated a set number of times. The first decompression can be omitted as the final decompression in the steam replacement step S2. Therefore, in the gas replacement step S3, after the completion of the steam replacement step S2, the return pressure to the return pressure target pressure PU and the pressure reduction to the pressure reduction target pressure PL are repeated a set number of times.

  Note that both the steam replacement step S2 and the gas replacement step S3 are steps in which the pressure reduction to the pressure reduction target pressure PL and the pressure reduction to the return pressure target pressure PU are repeated a set number of times. The number of times may be different from each other. Similarly, the pressure reduction target pressures PL in both steps may be different from each other, and the pressure reduction target pressures PU in both steps may be different from each other. These are not limited to the relationship between the steam replacement step S2 and the gas replacement step S3, and the same applies to the processes including the steam desorption step S5 and the air desorption step S6. The same applies to the holding time (set holding time) at the return pressure target pressure PU. In the illustrated example, in the vapor replacement step S2, the gas replacement step S3, the vapor desorption step S5, and the air desorption step S6, the pressure reduction target pressures PL of the respective steps are the same, except for the air desorption step S6, The return pressure target pressures PU in the process are also the same.

  The repetition of the reduction pressure in the gas replacement step S3 will be specifically described. First, when the pressure in the sterilization tank 2 is reduced, the inlet valve 10 and the outlet valve 11 are opened with the bypass valve 12 closed, and the vacuum pump 3 is activated. Thereby, the gas in the sterilization tank 2 is discharged through the catalytic reactor 6, and the formaldehyde contained in the exhaust gas is decomposed and rendered harmless by the catalyst. When the pressure detected by the pressure sensor 7 reaches the target pressure PL, the inlet valve 10 and the outlet valve 11 are closed and the vacuum pump 3 is stopped. Thereafter, when the second liquid supply valve 18 is opened, the formalin in the formalin tank 14 is sucked into the vaporizer 15, and formaldehyde gas evaporated in the vaporizer 15 (strictly, as described above, formaldehyde-containing water vapor) It is introduced in. When the inside of the sterilization tank 2 reaches the return pressure target pressure PU, the second liquid supply valve 18 is closed. Then, the repetition of such pressure reduction and return pressure is executed a set number of times.

  However, as shown in the illustrated example, after formaldehyde gas is introduced into the sterilization tank 2 and the pressure is restored to the return pressure target pressure PU, the set pressure may be held for a set holding time (for example, 30 seconds). . Further, the return pressure in the sterilization tank 2 may not be until the detected pressure of the pressure sensor 7 reaches the return pressure target pressure PU but until the set release time elapses from the opening of the second liquid supply valve 18. In any case, the water vapor in the sterilization tank 2 is replaced with formaldehyde gas by repeating the decompression in the sterilization tank 2 and the return pressure by introducing formaldehyde gas in the gas replacement step S3. In other words, the sterilization tank 2 is filled with formaldehyde gas having a concentration corresponding to that in the formalin tank 14.

≪Sterilization step S4≫
In the sterilization step S4, the inside of the sterilization tank 2 is held at the sterilization temperature for the sterilization time. Here, the sterilization tank 2 is maintained at the sterilization pressure (PU in the illustrated example) with the final re-pressure in the gas replacement step S3 (re-pressure by introducing formaldehyde gas into the sterilization tank 2). The inside of 2 is kept at sterilization temperature for sterilization time.

  Specifically, in the sterilization step S4, the introduction of formaldehyde gas into the sterilization tank 2 (more specifically, the second liquid supply) so that the temperature detected by the temperature sensor 8 maintains the sterilization temperature (eg, 55 ° C.). By controlling the valve 18) and maintaining the sterilization time (for example, 60 minutes), the sterilized material in the sterilization tank 2 is sterilized. Alternatively, the introduction of formaldehyde gas into the sterilization tank 2 is controlled so as to maintain the sterilization time so that the detected pressure of the pressure sensor 7 maintains the sterilization pressure (saturated steam pressure corresponding to the sterilization temperature). Sterilize the sterilized material in 2. Thereafter, the process proceeds to the next step with the second liquid supply valve 18 closed.

≪Vapor desorption process S5≫
In the vapor desorption process S5, the depressurization in the sterilization tank 2 and the return pressure due to the introduction of water vapor are repeated a set number of times. Specifically, the depressurization to the depressurization target pressure PL by the vacuum pump 3 and the depressurization to the depressurization target pressure PU by the introduction of water vapor are repeated a set number of times.

  The repetition of the depressurization pressure in the vapor desorption step S5 will be specifically described. First, when the pressure in the sterilization tank 2 is reduced, the inlet valve 10 and the outlet valve 11 are opened with the bypass valve 12 closed, and the vacuum is released. The pump 3 is activated. Thereby, the gas in the sterilization tank 2 is discharged via the catalytic reactor 6, and the formaldehyde contained in the exhaust gas is rendered harmless by the catalyst. When the pressure detected by the pressure sensor 7 reaches the target pressure PL, the inlet valve 10 and the outlet valve 11 are closed and the vacuum pump 3 is stopped. Thereafter, when the first liquid supply valve 17 is opened, water in the water tank 13 is sucked into the vaporizer 15, and water vapor evaporated in the vaporizer 15 is introduced into the sterilization tank 2. When the inside of the sterilization tank 2 reaches the return pressure target pressure PU, the first liquid supply valve 17 is closed. Then, the repetition of such pressure reduction and return pressure is executed a set number of times.

  However, as shown in the illustrated example, after introducing water vapor into the sterilization tank 2 and returning the pressure to the return pressure target pressure PU, the set retention time (in the illustrated example, the steam replacement step S2 and the gas replacement step) is reached. It may be held only for a time shorter than the set holding time in S3. The return pressure in the sterilization tank 2 may not be until the detected pressure of the pressure sensor 7 reaches the return pressure target pressure PU, but until the set release time elapses from the opening of the first liquid supply valve 17. In any case, in the vapor desorption step S5, by repeatedly reducing the pressure in the sterilization tank 2 and returning the pressure by introducing water vapor, the formaldehyde in the sterilization tank 2 is eliminated and replaced with water vapor containing no formaldehyde.

≪Air desorption process S6≫
In the air detaching step S6, the decompression in the sterilization tank 2 and the return pressure by introducing air are repeated a set number of times. Specifically, the depressurization up to the depressurization target pressure PL by the vacuum pump 3 and the depressurization up to the decompression target pressure PU by introducing air are repeated a set number of times. The first decompression can be omitted as the final decompression in the vapor desorption step S5. Therefore, in the air desorption process S6, after the completion of the vapor desorption process S5, the return pressure to the return pressure target pressure PU and the pressure reduction to the pressure reduction target pressure PL are repeated a set number of times.

  In this embodiment, the pressure reduction target pressure PL in the air desorption process S6 is the same as the pressure reduction target pressure PL in the steam replacement process S2, the gas replacement process S3, and the steam desorption process S5. On the other hand, the return pressure target pressure PU in the air desorption process S6 is preferably set higher than the return pressure target pressures PU in the steam replacement process S2, the gas replacement process S3, and the steam desorption process S5. The pressure should be close to that.

  The repetition of the depressurization pressure in the air detaching step S6 will be specifically described. First, when the pressure in the sterilization tank 2 is reduced, the bypass valve 12 is opened with the inlet valve 10 and the outlet valve 11 closed, and the vacuum is reduced. The pump 3 is activated. When the pressure detected by the pressure sensor 7 reaches the pressure reduction target pressure PL, the bypass valve 12 is closed and the vacuum pump 3 is stopped. Thereafter, when the air supply valve 22 is opened, outside air is introduced into the sterilization tank 2. When the inside of the sterilization tank 2 reaches the return pressure target pressure PU, the air supply valve 22 is closed. Then, the repetition of such pressure reduction and return pressure is executed a set number of times.

  However, when the pressure in the sterilization tank 2 is reduced, the gas from the sterilization tank 2 may be passed through the catalytic reactor 6. That is, when the pressure in the sterilization tank 2 is reduced, the vacuum valve 3 may be operated by opening the inlet valve 10 and the outlet valve 11 with the bypass valve 12 closed. Thereby, since the gas in the sterilization tank 2 is discharged through the catalytic reactor 6, even if formaldehyde remains in the sterilization tank 2, the formaldehyde is rendered harmless by the catalyst. When the pressure detected by the pressure sensor 7 reaches the target pressure PL, the inlet valve 10 and the outlet valve 11 are closed, the vacuum pump 3 is stopped, and the air supply valve 22 is opened.

  In any case, in the air detachment step S6, by repeating the decompression in the sterilization tank 2 and the return pressure by introducing air, the steam is removed from the sterilization tank 2 and replaced with air. Finally, with the vacuum pump 3 stopped, the air supply valve 22 is opened, and the inside of the sterilization tank 2 is restored to atmospheric pressure. Thereafter, the door of the sterilization tank 2 is opened, and the sterilized product can be taken out from the sterilization tank 2.

  According to the low temperature steam formaldehyde sterilization apparatus 1 of the present embodiment, the formaldehyde contained in the exhaust gas can be decomposed by passing the exhaust gas from the sterilization tank 2 to the vacuum pump 3 through the catalytic reactor 6. Thereby, the inflow of formaldehyde into the vacuum pump 3 can be prevented, and the penetration of formaldehyde into the sealing water and consequently the waste water can be prevented. Further, a large amount of water for diluting formaldehyde is not required, and the running cost can be reduced.

  In addition, it is possible to switch whether or not the exhaust from the sterilization tank 2 is passed through the catalytic reactor 6. Therefore, according to the gas in the sterilization tank 2 (in other words, according to the operation process), it is possible to switch whether or not the exhaust gas from the sterilization tank 2 is passed through the catalytic reactor 6. When exhausting through the catalytic reactor 6, formaldehyde can be decomposed in the catalytic reactor 6, and when exhausting through the catalytic reactor 6, the pressure loss is reduced by the amount not passing through the catalytic reactor 6. Thus, the exhaust time can be shortened. At least in the gas replacement step S3 and the vapor desorption step S5 in which formaldehyde is contained in the exhaust from the sterilization tank 2, the gas from the sterilization tank 2 is preferably exhausted through the catalyst reactor 6. In the air detachment step S6, even when formaldehyde remains in the sterilization tank 2, it is made harmless by exhausting it through the catalytic reactor 6 when evacuating from the sterilization tank 2. Can be exhausted.

  FIG. 3 is a schematic view showing a modified example of the low-temperature steam formaldehyde sterilizer 1 of the embodiment. This modification (FIG. 3) is also basically the same as the embodiment (FIG. 1). Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  This modification is different from the previous embodiment in the configuration of the exhaust system from the sterilization tank 2 to the vacuum pump 3. This will be specifically described below. First, the exhaust path 9 from the inside of the sterilization tank 2 branches into the first exhaust path 9a and the second exhaust path 9b, and then merges again and is connected to the vacuum pump 3 as in the above embodiment. However, the first exhaust path 9a is provided with an inlet valve 10, a catalytic reactor 6, a communication valve 23, a tank 24, and an outlet valve 11 in this order. On the other hand, a bypass valve 12 is provided in the second exhaust passage 9b as in the above embodiment. As will be described later, by controlling the opening / closing of the valves 10, 11, 12, and 23, it is possible to switch between exhausting through the first exhaust passage 9a and exhausting through the second exhaust passage 9b. .

  In addition to the catalyst reactor 6, the configurations of the inlet valve 10, the outlet valve 11 and the bypass valve 12 are the same as in the above embodiment. The tank 24 is a hollow container smaller than the sterilization tank 2 and is heated to a set temperature (for example, 55 ° C., which is the same as the heating temperature in the sterilization tank 2) by a heater (for example, heat tape). The tank 24 is connected to the catalytic reactor 6 through the communication valve 23 and is connected to the vacuum pump 3 through the outlet valve 11.

  In order to exhaust air through the first exhaust passage 9a, the outlet valve 11 is opened with the bypass valve 12 closed and the inlet valve 10 and the communication valve 23 are closed. The inside of 24 is depressurized to a predetermined pressure (first operation). This predetermined pressure is a pressure lower than the pressure in the sterilization tank 2. Thereafter, with the outlet valve 11 closed, the inlet valve 10 and the communication valve 23 are opened, and the inside of the sterilization tank 2 is depressurized (second operation). That is, the gas in the sterilization tank 2 is sucked into the tank 24 through the catalyst reactor 6 by communicating the inside of the sterilization tank 2 and the tank 24 through the catalyst reactor 6. At that time, formaldehyde contained in the exhaust gas from the sterilization tank 2 is decomposed and rendered harmless by the catalyst. Thereafter, with the inlet valve 10 and the communication valve 23 closed again, the outlet valve 11 is opened to decompress the tank 24 (third operation). As a result, the water vapor remaining in the tank 24 can be eliminated, and the pressure in the tank 24 can be reduced to a predetermined pressure again.

  When exhausting the gas containing formaldehyde from the sterilization tank 2, it is preferable to exhaust the gas via the first exhaust path 9a by performing the third operation from the first operation described above. For example, in the gas replacement step S3 and the vapor desorption step S5, as described in the above embodiment, the decompression and the decompression are repeated a set number of times, and each decompression is performed from the first operation to the third operation. Should be done in one set of implementations. That is, it is preferable to set the inside of the tank 24 to a predetermined pressure lower than the pressure reduction target pressure PL by the first operation and to reduce the pressure in the sterilization tank 2 to the pressure reduction target pressure PL by the second operation. Considering this point, the capacity of the tank 24 and the pressure reduction level (by the first operation) are set.

  The pressure reduction (first operation) in the tank 24 can be performed in advance (that is, before the start of the process) in the gas replacement step S3, for example, or during the decompression by introducing formaldehyde gas into the sterilization tank 2 after the pressure reduction. In addition to the vapor desorption step S5, it can be performed in advance (that is, before the start of the process), and in parallel during the decompression by introducing water vapor into the sterilization tank 2 after decompression. be able to.

  On the other hand, in order to exhaust through the second exhaust path 9b, the bypass valve 12 is opened and the vacuum pump 3 is exhausted with the inlet valve 10 and the outlet valve 11 closed as in the above embodiment. Good. Other configurations and operation methods are the same as those in the above embodiment, and thus the description thereof is omitted.

  Next, a specific example of the catalytic reactor 6 used in the low-temperature steam formaldehyde sterilizer 1 of the embodiment (including the modified example) will be described. As described above, the catalytic reactor 6 includes a reaction vessel, a catalyst, and a heater.

  The reaction container is a container through which gas from the sterilization tank 2 is passed, and is typically formed from a cylindrical material such as a cylinder or a rectangular tube. A catalyst for decomposing formaldehyde is provided in the reaction vessel. Typically, the cylindrical reaction vessel is provided with a catalyst in the middle in the axial direction, and gas from the sterilization tank 2 to the vacuum pump 3 passes from one opening to the other opening. Is done.

  The reaction vessel is provided with a heater, and the catalyst is heated by this heater. For example, a mantle heater is provided so as to cover the entire peripheral side wall of the reaction vessel from the outside. Before the gas from the sterilization tank 2 is passed through the catalyst, the heater heats the catalyst to a set temperature (150 ° C. or higher, preferably 200 to 250 ° C.) by the heater, and then maintains the set temperature. Is controlled. In addition, while the gas containing formaldehyde passes through the catalyst, the temperature of the catalyst becomes higher than the set temperature, but is suppressed to be lower than the spontaneous ignition temperature of formaldehyde.

  By the way, it is preferable that the heater not only warms the catalyst but also warms a gas (for example, a gas of 50 to 55 ° C.) from the sterilization tank 2 to the catalyst. That is, the gas from the sterilization tank 2 is preferably heated in the reaction container so that the set temperature is 150 ° C. or more immediately before the catalyst. In order to realize this easily and compactly, the catalytic reactor 6 is preferably configured as follows.

  FIG. 4 is a schematic cross-sectional view showing an example of the catalytic reactor 6. In this example, the catalytic reactor 6 has a double tube structure including an inner cylinder 25 and an outer cylinder 26, and a catalyst 27 is provided in the inner cylinder 25, while the outer cylinder 26 is added by a heater (not shown). Be warmed. The gas from the inside of the sterilization tank 2 passes through the gap between the inner cylinder 25 and the outer cylinder 26, and then turns back and passes through the inner cylinder 25.

  More specifically, the inner cylinder 25 is accommodated in the outer cylinder 26 with the axes aligned. The inner cylinder 25 and the outer cylinder 26 each have a fluid inlet / outlet at one axial end (right end in FIG. 4) and are closed by an end wall 28 at the other axial end (left end in FIG. 4). That is, the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 is closed by the end wall 28 at the other axial end, and the hollow hole of the inner cylinder 25 is also closed by the same end wall 28. A plurality of communication portions (through holes or notches) 29 are formed on the peripheral side wall of the inner cylinder 25 at positions close to the end wall 28 and spaced apart in the circumferential direction. The inside and outside of the inner cylinder 25 communicate with each other. That is, the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 and the hollow hole of the inner cylinder 25 communicate with each other via the communication portion 29 provided on the peripheral side wall of the inner cylinder 25.

  On the other hand, at one end in the axial direction, the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 is connected to the pipe from the sterilization tank 2, and the hollow hole of the inner cylinder 25 is connected to the pipe to the vacuum pump 3. Is done. In the illustrated example, an end wall 30 is also provided at one end in the axial direction, and this end wall 30 closes the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 and the hollow hole of the inner cylinder 25. It is done. However, through holes 30a and 30b are formed in the end wall 30 at positions corresponding to the cylindrical gaps and the hollow holes, respectively. Then, piping from the sterilization tank 2 and piping to the vacuum pump 3 are connected to the pipe portions provided in the through holes 30a and 30b. In addition, a catalyst 27 is provided in the central portion of the inner cylinder 25 in the axial direction.

  Further, the outer cylinder 26 of the catalyst reactor 6 is provided with a heater (not shown). For example, in addition to the peripheral side wall of the outer cylinder 26, a mantle heater is preferably provided so as to cover the end walls 28 and 30 (at least the end wall 28 at the other end in the axial direction). By operating this heater, the inside of the outer cylinder 26, that is, the inside of the inner cylinder 25 and the catalyst 27 can be heated to the set temperature.

  When the gas in the sterilization tank 2 is discharged by the vacuum pump 3 via the catalyst reactor 6, the catalyst 27 is heated to a set temperature in advance with a heater. Since the reaction vessel (25, 26) has a double-pipe structure, it is difficult to heat the catalyst as compared with the case of a single pipe (only the inner cylinder 25). In the evacuation step S1 and the steam replacement step S2, since the exhaust is performed through the second exhaust passage 9b (that is, not through the catalyst reactor 6), it is possible to secure a time for heating the catalyst 27 with a heater during that time. it can.

By the way, the decomposition reaction of formaldehyde requires oxygen as shown by the reaction formula “HCHO + O ₂ → CO ₂ + H ₂ O”. However, as described in the above embodiment, after the air is removed from the sterilization tank 2 in the evacuation process S1 and the steam replacement process S2, formaldehyde gas is introduced into the sterilization tank 2 (gas replacement process). S3) Sterilization is achieved under vacuum. Therefore, even when formaldehyde is passed through the catalytic reactor 6 during exhaust from the sterilization tank 2, there is a risk that the expected decomposition is not performed due to lack of oxygen. Therefore, it is preferable that the gas from the inside of the sterilization tank 2 is passed through the catalytic reactor 6 after air from outside is mixed therein.

  In the illustrated example, an air hole 30c is formed in the end wall 30 at one end in the axial direction (a position communicating with the cylindrical gap) as an outside air intake. Therefore, when evacuation is performed, air from outside is automatically drawn into the gas from the inside of the sterilization tank 2, and after the gap between the inner cylinder 25 and the outer cylinder 26 is passed, Passed through catalyst 27. In the meantime, mixing of the gas from the inside of the sterilization tank 2 and the air from the outside and heating by a heater are performed. Moreover, excessive temperature rise in the catalyst 27 can also be suppressed by diluting the formaldehyde gas from the sterilization tank 2 with air.

  Furthermore, a valve may be provided in a pipe line to the air hole 30c so that the opening / closing or opening degree of the valve can be adjusted. In addition, the air hole 30c is not limited to the end wall 30 at one end in the axial direction, and may be formed in the outer cylinder 26. In some cases, the air hole 30c may be formed in a pipe from the sterilization tank 2 to the catalyst reactor 6. . In any case, the formaldehyde can be reliably decomposed by mixing air into the gas from the sterilization tank 2 and passing it through the catalytic reactor 6.

  Note that the posture of the catalyst reactor 6 is not limited to the horizontal direction, and may be the vertical direction or the diagonal direction. That is, in FIG. 4, the catalytic reactor 6 has the inner cylinder 25 and the outer cylinder 26 arranged in the left-right direction, but is arranged in the up-down direction or diagonally. Also good. In the case of arranging vertically or obliquely, any of the pair of end walls 28 and 30 may be directed upward. Since the fluid passed through the catalyst reactor 6 is basically only gas, the posture and installation direction of the catalyst reactor 6 can be changed as appropriate. Moreover, although the inner cylinder 25 and the outer cylinder 26 were comprised from the cylinder in the example of illustration, you may be comprised from square cylinders, such as a cross-sectional square, depending on the case.

  FIG. 5 is a schematic cross-sectional view showing another example of the catalytic reactor 6. The catalytic reactor 6 in FIG. 5 is basically the same as the catalytic reactor 6 in FIG. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the catalytic reactor 6 of FIG. 4, the opening at the other axial end of the inner cylinder 25 and the outer cylinder 26 (left end in FIG. 4) is closed by the end wall 28, and the other axial end of the inner cylinder 25 is also closed. Although the communication part 29 was provided in the surrounding side wall, and the inside and outside of the inner cylinder 25 were connected, in the catalyst reactor 6 of FIG. 5, although the opening part of the axial direction other end part of the outer cylinder 26 is closed by the end wall 28, The other end of the inner cylinder 25 in the axial direction is spaced apart from the end wall 28 and has a gap. The gap (the gap between the other axial end portion of the inner cylinder 25 and the end wall 28) functions as a communication portion 29 that communicates the inside and the outside of the inner cylinder 25. Also in this case, the gas flowing from the one axial end to the other axial end through the cylindrical gap between the inner cylinder 25 and the outer cylinder 26 is folded back at the other axial end and enters the inner cylinder 25 in the axial direction. It flows toward one end and is led out through a catalyst 27 in the inner cylinder 25. Other configurations are the same as those in FIG.

  The low-temperature steam formaldehyde sterilization apparatus 1 of the present invention is not limited to the configuration (including control) of the above-described embodiment (including modifications), and can be changed as appropriate. In particular, (a) a sterilization tank 2 in which sterilized materials are stored, (b) a water-sealed vacuum pump 3 for sucking and discharging the gas in the sterilization tank 2 to the outside, and (c) a vacuum pump from the sterilization tank 2 As long as it is provided with the catalytic reactor 6 that decomposes formaldehyde and is provided in the exhaust passage 9 to 3, the other configurations can be appropriately changed.

  For example, in the embodiment, the exhaust through the first exhaust passage 9a and the exhaust through the second exhaust passage 9b are performed by switching the inlet valve 10, the outlet valve 11 and the bypass valve 12. The specific configuration whether or not to pass through the catalyst reactor 6 is not particularly limited. As an example, instead of the inlet valve 10 and the bypass valve 12, a three-way valve may be provided at a branch portion between the first exhaust path 9 a and the second exhaust path 9 b, or instead of the outlet valve 11 and the bypass valve 12. A three-way valve may be provided at the junction of the first exhaust passage 9a and the second exhaust passage 9b.

  Moreover, in the said Example, the bypass valve 12 of the 2nd exhaust passage 9b can be abbreviate | omitted by the case. Alternatively, the installation of the second exhaust path 9b itself may be omitted. That is, the exhaust from the sterilization tank 2 may always be discharged by the vacuum pump 3 via the catalytic reactor 6. In that case, installation of the outlet valve 11 can be omitted in addition to the second exhaust passage 9b.

  In the above embodiment, the evacuation step S1, the vapor replacement step S2, the gas replacement step S3, the sterilization step S4, the vapor desorption step S5, and the air desorption step S6 are sequentially performed. , The presence / absence and content of each process can be changed as appropriate. For example, the evacuation step S1 can be used to check for leakage during decompression in the sterilization tank 2 (outflow of outside air into the sterilization tank 2) and to determine the number of times of decompression pressure in each subsequent process. However, when the leak check is not performed and the set number of times is fixed, the evacuation step S1 can be omitted. The steam replacement step S2 is intended to exclude air from the sterilization tank 2, but formaldehyde gas can be used instead of water vapor. Therefore, instead of not performing the steam replacement step S2, the number of times of reduced pressure in the gas replacement step S3 may be increased.

1 Low-temperature steam formaldehyde sterilizer 2 Sterilization tank 3 Vacuum pump (3a: intake port, 3b: exhaust port)
4 Introducing means for water vapor and formaldehyde gas 5 Introducing means for outside air 6 Catalytic reactor 7 Pressure sensor 8 Temperature sensor 9 Exhaust path (9a: first exhaust path, 9b: second exhaust path)
DESCRIPTION OF SYMBOLS 10 Inlet valve 11 Outlet valve 12 Bypass valve 13 Water tank 14 Formalin tank 15 Vaporizer 16 Supply path (16a: 1st supply path, 16b: 2nd supply path)
17 First supply valve 18 Second supply valve 19 Communication path 20 Supply path 21 Air filter 22 Supply valve 23 Communication valve 24 Tank 25 Inner cylinder 26 Outer cylinder 27 Catalyst 28 End wall 29 Communication section 30 End wall (30a : Through hole, 30b: Through hole, 30c: Air hole)
P0 Atmospheric pressure P1 Minimum pressure PL Depressurization target pressure PU Return pressure target pressure S1 Vacuum evacuation process S2 Steam replacement process S3 Gas replacement process S4 Sterilization process S5 Steam desorption process S6 Air desorption process

Claims (6)

A sterilization tank for storing sterilized materials;
A water-sealed vacuum pump that sucks and discharges the gas in the sterilization tank to the outside,
A low temperature steam formaldehyde sterilization apparatus, comprising: a catalytic reactor provided in an exhaust path from the sterilization tank to the vacuum pump, and decomposing formaldehyde. By changing the flow path of the exhaust path, it is possible to switch whether the gas in the sterilization tank is discharged via the catalytic reactor or not via the catalytic reactor. The low-temperature steam formaldehyde sterilizer according to claim 1. A gas replacement step that repeats the decompression in the sterilization tank and a return pressure by introducing formaldehyde gas, a sterilization step that maintains the inside of the sterilization tank at a sterilization temperature for a sterilization time, And a vapor desorption step that repeats the above, and an air desorption step that repeats the depressurization in the sterilization tank and the return pressure due to the introduction of air in sequence,
3. The low-temperature steam according to claim 2, wherein in the gas replacement step and the vapor desorption step, the gas in the sterilization tank is discharged through the catalytic reactor when the pressure in the sterilization tank is reduced. Formaldehyde sterilizer. The exhaust path from the inside of the sterilization tank branches to the first exhaust path and the second exhaust path, and then merges again and is connected to the vacuum pump,
In the first exhaust path, an inlet valve, a catalytic reactor, a communication valve, a tank and an outlet valve are provided in this order,
It is possible to switch between exhausting through the first exhaust path or exhausting through the second exhaust path,
When exhausting through the first exhaust path, the inlet valve and the communication valve are closed, the outlet valve is opened, the inside of the tank is depressurized, and the outlet valve is closed. The pressure inside the sterilization tank is reduced by opening a valve and the communication valve, and then the pressure inside the tank is reduced by opening the outlet valve with the inlet valve and the communication valve closed again. The low-temperature steam formaldehyde sterilizer according to claim 2 or claim 3. The catalyst reactor has a double tube structure composed of an inner cylinder and an outer cylinder, and a catalyst is provided in the inner cylinder, while the outer cylinder is heated by a heater,
5. The low-temperature steam according to claim 1, wherein the gas from the inside of the sterilization tank is passed through the inner cylinder after passing through a gap between the inner cylinder and the outer cylinder. Formaldehyde sterilizer. 6. The low-temperature steam formaldehyde sterilizer according to claim 1, wherein the gas from the inside of the sterilization tank is mixed with air from the outside and then passed through the catalytic reactor. .

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