JP4257256B2 - Oxygen concentrator - Google Patents

Description

  The present invention relates to an oxygen concentrator that uses an adsorbent that preferentially adsorbs nitrogen over oxygen and supplies a high concentration of oxygen to a patient or the like by a pressure fluctuation adsorption method.

Conventionally, a medical oxygen concentrator has been used for home oxygen therapy and the like as a device capable of supplying high concentration oxygen to a patient or the like.
As this type of oxygen concentrator, for example, an adsorption type oxygen concentrator in which an adsorbent that preferentially adsorbs nitrogen over oxygen is filled in a plurality of (for example, two) adsorption cylinders is known. As a home oxygen therapy device, a pressure fluctuation adsorption type oxygen concentrator using a compressor is used.

  In the pressure fluctuation adsorption oxygen concentrator, in general, air is supplied to the adsorption cylinder by an air supply means to make the inside of the cylinder pressurized, thereby adsorbing nitrogen in the air to the adsorbent and oxygen. The adsorption process, which is concentrated and taken out, and the regeneration process (exhaust process) in which the adsorption cylinder is desorbed by releasing the adsorption cylinder to the atmosphere and reducing the pressure, are repeated alternately or sequentially. Oxygen-enriched gas is generated.

Further, in recent years, in order to efficiently obtain higher concentration of oxygen, the adsorption cylinder is opened to the atmosphere and depressurized to desorb the adsorbed nitrogen, and the product gas stored in the surge tank (oxygen enriched gas) By purging the inside of the adsorption cylinder to regenerate the adsorbent (see Patent Document 1), or by using the air compression means and exhausting until the inside of the adsorption cylinder becomes negative pressure A method of regenerating the adsorbent by desorbing the adsorbed nitrogen has been performed (see Patent Document 2).
JP 2003-180837 A (2nd page, FIG. 1) Japanese Patent Laid-Open No. 7-155526 (2nd page, FIG. 1)

However, since the medical oxygen concentrator is used for treatment of patients, long-term safety and stability are required, and therefore further improvement is required.
That is, in the oxygen concentrator, hydrophilic adsorbents such as 5A-type, 13X-type zeolite, or Li-substituted X-type zeolite are often used as adsorbents. It is known that moisture adsorbs and nitrogen adsorption performance gradually declines and oxygen concentration decreases.

  In order to prevent this decrease in oxygen concentration, there are known methods for draining and removing moisture in compressed air, and methods for arranging an adsorbent such as silica gel and activated alumina separately from the oxygen-concentrating adsorbent on the oxygen supply side of the adsorption cylinder. It has been.

However, the measures described above have problems such as the complexity of the apparatus and the life of the hygroscopic agent, and the life extension effect of the adsorbent is recognized, but it cannot be said to be sufficient.
Further improvements were also sought in the medical field.

  The present invention has been made to solve the above-mentioned problems, and its object is to improve the life of the adsorbent of the oxygen concentrator used at home for a long time, for example, with a simple configuration, It is to provide an oxygen concentrator that enables stable treatment and the like.

(1) The invention of claim 1 is characterized in that at least two adsorption cylinders filled with an adsorbent that preferentially adsorbs nitrogen over oxygen, and an air supply means (for example, a compressor) that supplies air to the adsorption cylinder and pressurizes it. And a pressure change switching means (for example, a switching valve) for controlling pressure increase / decrease in the adsorption cylinder, and in the pressure fluctuation adsorption type oxygen concentrator for generating oxygen concentrated gas from the air, the oxygen concentration When an instruction to stop the operation of the vessel is given, it waits until it reaches the switching timing of intake (supplying air to the adsorption cylinder) or exhaust (exhaust gas from the adsorption cylinder) in the adsorption cylinder, and then the oxygen The supply of the oxygen enriched gas is shut off by a supply shut-off means (for example, a solenoid valve), and at least one of the oxygen concentrators is operated while the supply of the oxygen enriched gas to the outside is shut off. Sucking To produce oxygen enriched gas in the cylinder, the oxygen-enriched gas thus generated is supplied as a purge gas to another adsorption column, and removing water from the adsorbent.

In the present invention, for example, when the operation of the operation stop switch is operated to stop the operation of the oxygen concentrator , the oxygen supply is performed after waiting until the switching timing of the intake or exhaust in the adsorption cylinder is reached. The supply of oxygen-enriched gas to the outside is shut off by the shut-off means, and the oxygen concentrator is operated in this state to generate oxygen-enriched gas in the adsorption cylinder, and the generated oxygen-enriched gas is supplied as purge gas to the other adsorption cylinders. To remove moisture from the adsorbent.

As described above, since not only nitrogen but also water is adsorbed by the adsorbent, the life of the adsorbent is reduced as it is. Therefore, in the present invention, when the operation stop is instructed, the supply of the oxygen enriched gas to the outside is shut off, and the oxygen enriched gas is generated as it is. The oxygen-enriched gas is a dry gas containing high concentration oxygen (for example, 95% by weight oxygen) and having moisture removed by an adsorbent. Accordingly, by supplying this oxygen-enriched gas as a purge gas to the other adsorption cylinder, moisture can be released from the adsorbent in the adsorption cylinder and discharged out of the adsorption cylinder. Thereby, since the moisture contained in the adsorbent can be reduced, the life of the adsorbent can be effectively extended with a simple configuration.
In particular, in the present invention, when the stop of the operation of the oxygen concentrator is instructed, the operation waits until the intake or exhaust gas switching timing in the adsorption cylinder is reached, and then the supply from the oxygen supply shut-off means to the supply of purge gas is reached. Perform a purge process.
When the operation stop of the oxygen concentrator is instructed, if the process immediately shifts to the purge process step, the pressure in one adsorption cylinder may increase excessively, and the pressure between the adsorption cylinders becomes unbalanced.
Therefore, in the present invention, the process waits until the intake or exhaust gas switching timing is reached and then proceeds to the purge process. Therefore, a purge gas (oxygen-enriched gas) having a moderately set pressure (for example, slightly higher than normal pressure) , Can be supplied to the adsorption cylinder to remove moisture.
The reason why an excessive increase in pressure can be prevented by the operation of the present invention is as follows.
When the operation stoppage is instructed and the process proceeds to the purge process step, the pressure between the adsorption cylinders at the moment when the operation stop instruction is issued may not be uniform. Generally, since the switching timing of intake and exhaust is controlled by time, when one of the in-cylinder pressures is switched, the pressure increases correspondingly and the pressure between the adsorption cylinders becomes unbalanced. End up.
On the other hand, in the present invention, the process waits until the intake or exhaust gas switching timing is reached, and then proceeds to the purge process, so that the pressure between the adsorption cylinders always starts from a uniform state. An imbalance does not occur and therefore an excessive increase in pressure can be prevented.

Here, the purge gas is a gas for removing moisture from the adsorbent (ie, oxygen-enriched gas).
The supply of oxygen-enriched gas to the outside is shut off by the oxygen supply shut-off means, and in this shut-off state, the oxygen concentrator is operated to generate oxygen-enriched gas with at least one adsorption cylinder. The process of supplying the gas to the other adsorption cylinder as a purge gas to remove the moisture of the adsorbent is referred to as a purge process.

(2) The invention of claim 2 is characterized in that at least two adsorption cylinders filled with an adsorbent that preferentially adsorbs nitrogen over oxygen, air supply means for supplying air to the adsorption cylinder and pressurizing, and the adsorption A pressure-change / pressure switching means for controlling pressure increase / decrease in the cylinder, and in a pressure fluctuation adsorption type oxygen concentrator that generates oxygen-concentrated gas from the air, when the operation stop of the oxygen concentrator is instructed The oxygen supply shut-off means shuts off the supply of the oxygen enriched gas to the outside, and operates the oxygen concentrator in a state where the supply of the oxygen enriched gas to the outside is shut off. An oxygen-enriched gas is generated in the adsorption cylinder, the generated oxygen-enriched gas is supplied as a purge gas to other adsorption cylinders, the moisture in the adsorbent is removed, and further, after the purge gas is supplied, Stop driving When until it stops the operation, and maintains the open state of the pressure equalizing valve that communicates the adsorption column which supplies the purge gas and the adsorption cylinder that generated oxygen enriched gas.
In the present invention, for example, when an operation stop of the oxygen concentrator is instructed by operating an operation stop switch, supply of oxygen concentrated gas to the outside is interrupted by the oxygen supply interrupting means, and in this state The oxygen concentrator is operated to generate an oxygen-enriched gas in the adsorption cylinder, and the generated oxygen-enriched gas is supplied as a purge gas to the other adsorption cylinder to remove moisture from the adsorbent.
As described above, since not only nitrogen but also water is adsorbed by the adsorbent, the life of the adsorbent is reduced as it is. Therefore, in the present invention, when the operation stop is instructed, the supply of the oxygen enriched gas to the outside is shut off, and the oxygen enriched gas is generated as it is. The oxygen-enriched gas is a dry gas containing high concentration oxygen (for example, 95% by weight oxygen) and having moisture removed by an adsorbent. Accordingly, by supplying this oxygen-enriched gas as a purge gas to the other adsorption cylinder, moisture can be released from the adsorbent in the adsorption cylinder and discharged out of the adsorption cylinder. Thereby, since the moisture contained in the adsorbent can be reduced, the life of the adsorbent can be effectively extended with a simple configuration.
In particular, in the present invention, when the operation of the oxygen concentrator is stopped after supplying the purge gas, the pressure equalizing valve that communicates the adsorption cylinder that generates the oxygen concentrated gas and the adsorption cylinder that supplies the purge gas until the operation is stopped. Keep the valve open.
That is, in the present invention, when the operation of the oxygen concentrator is stopped, the open state of the pressure equalizing valve that connects the adsorption cylinder that generates the oxygen-enriched gas and the adsorption cylinder that supplies the purge gas is maintained. Therefore, the state of moisture and the like contained in the internal adsorbent is made uniform.
( 3 ) The invention of claim 3 is characterized in that the purge gas is supplied by repeating the intake and exhaust strokes (adsorption / desorption stroke) of the adsorption cylinder at least one cycle or more.
In the present invention, the adsorption and desorption process of the adsorption cylinders is repeated at least one cycle and the purge gas is supplied, so that moisture can be sufficiently removed from the adsorbent in each adsorption cylinder and the state in each adsorption cylinder becomes uniform. Is done. That is, it is possible to prevent the state of moisture and the like contained in the adsorbent in each adsorption cylinder from becoming uniform and shortening only the life of the adsorbent in the specific adsorption cylinder.

  Here, the adsorption / desorption process refers to an intake process in which air is pressurized and supplied to the adsorption cylinder, and nitrogen is adsorbed by the adsorbent to concentrate oxygen, and an internal gas (such as air) is discharged from the adsorption cylinder under reduced pressure. An exhaust stroke in which nitrogen adsorbed by the adsorbent is released and discharged, and one cycle of the adsorption / desorption stroke is to perform an intake stroke and an exhaust stroke in the adsorption cylinder.

  For example, in the case of an oxygen concentrator having two adsorption cylinders, first, an oxygen enriched gas is generated in one adsorption cylinder, the other enriched cylinder is purged using the oxygen enriched gas, and then the operation is performed. The adsorption cylinder to be switched is switched to generate an oxygen-enriched gas in the other adsorption cylinder, and the one adsorption cylinder is purged using the oxygen-enriched gas. That is, such an operation means that purging is performed by performing an adsorption / desorption process of one cycle.

  (4) According to the invention of claim 4, when the operation of the oxygen concentrator is stopped after supplying the purge gas, the operation of the air supply means is stopped from the air supply means by the pressure increase / decrease switching means after the operation of the air supply means is stopped. The flow path for pressurization reaching the adsorption cylinder is blocked.

  In the present invention, when the operation of the oxygen concentrator is stopped, the operation of the air supply means is stopped, and then the flow path for pressurization from the air supply means to the adsorption cylinder is shut off by the pressure increase / decrease switching means. Therefore, there is an advantage that condensation does not easily occur.

The reason why condensation does not easily occur due to the operation of the present invention is as follows.
Normally, when the operation of the air supply means and the pressure increase / decrease switching means is stopped simultaneously when the power supply is stopped, the inside of the pipeline from the air supply means to the pressure increase / decrease switch means The compressed air will be trapped. Since the amount of saturated water vapor decreases in inverse proportion to the pressure of the air, the compressed air has a high relative humidity. However, since the compressed air at this time is heated by the compression heat and the heat generated by the air compression means, the amount of saturated water vapor increases, so it is in a state where condensation is difficult to occur. If it decreases, it will become easy to dew condensation.

  On the other hand, in the present invention, when stopping the operation of the oxygen concentrator, after stopping the operation of the air supply means, by blocking the flow path from the air supply means to the adsorption cylinder by the pressure increase / decrease switching means, Since the pressure in the pipeline is released, condensation is less likely to occur.

  The pressure increase / decrease switching means refers to the application of pressure in the adsorption cylinder by, for example, opening and closing the flow path from the air supply means to the adsorption cylinder or opening and closing the flow path from the adsorption cylinder to the outside. For example, a three-way selector valve that switches between a communication state of the air supply means and the suction cylinder (blocked from the outside) and a communication state of the suction cylinder and the outside (blocked from the air supply means). Or a combination of a plurality of two-position on-off valves.

( 5 ) The invention according to claim 5 is characterized in that the oxygen supply gas is shut off from the outside by the oxygen supply shut-off means so that the purge gas is supplied from the adsorption cylinder during normal operation. characterized in that it was Redirecting a listen'll supply the amount of.
In the present invention, the supply of oxygen enriched gas to the outside is interrupted by the oxygen supply shut-off means, so that the purge of moisture is performed with the supply amount of the purge gas larger than the supply amount of the normal oxygen enriched gas. Moisture can be removed.

( 6 ) The invention of claim 6 is characterized in that the oxygen supply blocking means is an electromagnetic on-off valve or a flow rate proportional control valve.
The present invention exemplifies oxygen supply blocking means. Here, as the flow proportional control valve, a solenoid type flow proportional control valve or an actuator (driven by a brushless DC motor, a stepping motor or the like) type flow proportional control valve can be adopted. When this flow rate proportional control valve is used, the flow rate can be adjusted, so that a manual flow rate setting device can be omitted.

  Next, an example (example) of the best mode of the present invention will be described.

  In this embodiment, oxygen is concentrated by adsorbing and removing nitrogen from the air using a nitrogen adsorbent (hereinafter referred to as an adsorbent), and this oxygen-enriched gas containing high-concentration oxygen is supplied to the patient. An example is a pressure fluctuation adsorption type medical oxygen concentrator to be supplied (hereinafter referred to as an oxygen concentrator).

a) First, each configuration for realizing the function of the oxygen concentrator of the present embodiment will be described.
As shown in FIG. 1, the oxygen concentrator 1 has a compressor 5, a pair of three-way switching valves (a first switching valve 7 and a second switching valve 9) on the air introduction path 3 from the upstream side, A pair of adsorption cylinders (first adsorption cylinder 11 and second adsorption cylinder 13) filled with an adsorbent are provided. The pair of adsorption cylinders 11 and 13 are provided with exhaust passages 15 for exhausting nitrogen through the three-way switching valves 7 and 9.

  Furthermore, on the downstream side of the pair of adsorption cylinders 11, 13, a first communication path 17 that communicates between the adsorption cylinders 11, 13 and a pressure between the adsorption cylinders 11, 13 provided in the first communication path 17. Prevents the backflow of the oxygen-enriched gas, the two-way valve (pressure equalizing valve) 19 for adjusting the pressure, the second communication path 21 communicating between the adsorption cylinders 11 and 13, the orifice 23 provided in the second communication path 21 A pair of check valves 25, 27, a product tank 29 for storing oxygen-enriched gas, a pressure regulator (regulator) 31 that adjusts the pressure of the oxygen-enriched gas, and a flow rate that is a rotary switch that sets the flow rate of the oxygen-enriched gas A setter 33 and an electromagnetic open / close valve 37 (that is, an electromagnetic valve that operates at the open / close 2 position) 37 that shuts off the flow path 35 that supplies oxygen-enriched gas to the outside are provided.

The oxygen concentrator 1 of this embodiment is a device having a continuous base flow rate of 5 L / min.
In this embodiment, as shown in FIG. 2, the oxygen concentrator 1 is equipped with an electronic control device 41 that controls the operation of the oxygen concentrator 1.

  The electronic control device 41 includes a well-known microcomputer 43. A power switch 47, a flow rate setting device 33 and the like are connected to an input portion 45 of the electronic control device 41, and a compressor 5 and three directions are connected to an output portion 49 of the electronic control device 41. The switching valves 7 and 9, the pressure equalizing valve 19, the electromagnetic on-off valve 37, and the like are connected.

  Therefore, a signal indicating the operation of the power switch 47 and a signal indicating the set flow rate set by the flow rate setting unit 33 are input to the electronic control device 41. The electronic control device 41 outputs control signals for controlling the operations of the compressor 5, the three-way switching valves 7 and 9, the pressure equalizing valve 19, the electromagnetic open / close valve 37, and the like.

b) Next, main operations of the oxygen concentrator 1 of the present embodiment having the above-described configuration will be described.
In the oxygen concentrator 1 of the present embodiment, oxygen concentration and adsorbent regeneration are performed by alternately repeating pressurization and pressure reduction in the first adsorption cylinder 11 and the second adsorption cylinder 13.

  For example, the compressor 5 sends compressed air to the first adsorption cylinder 11 via the first switching valve 7, and adsorbs nitrogen to the adsorbent to concentrate oxygen. When a predetermined time has elapsed, the switching direction is switched to the other second adsorption cylinder 13 by the switching valves 7 and 9, the first adsorption cylinder 11 is connected to the atmosphere side, and the adsorbed nitrogen is reduced in pressure. To be discharged.

  In this way, only the oxygen is extracted at the time of pressurization by the adsorption cylinders 11 and 13, and the oxygen-enriched gas is passed through the downstream product tank 29, the pressure regulator 31, the flow rate setting device 33, and the electromagnetic on-off valve 37. To the outside (and thus the patient).

  By repeating this operation alternately for both adsorption cylinders 11 and 13, 90% or more of concentrated oxygen can be obtained continuously, and further, by accumulating in the product tank 29, fluctuations are reduced and continuity is improved. Secured. Since the adsorbent adsorbs not only nitrogen but also moisture, the oxygen-enriched gas supplied from the pressurized adsorption cylinders 11 and 13 is dried.

  In particular, in this embodiment, when the power switch 47 of the oxygen concentrator 1 is turned off, the electromagnetic on-off valve 37 is turned on to shut off the flow path 35. The operation of the vessel 1 is performed for one cycle. That is, in each of the adsorption cylinders 11 and 13, an adsorption process (a process in which air is pressurized and supplied to the adsorption cylinders 11 and 13 and nitrogen is adsorbed by the adsorbent to perform oxygen concentration) and an exhaust process (an adsorption cylinder 11 and 13). 13, the internal gas (air or the like) is discharged under reduced pressure, and the nitrogen adsorbed by the adsorbent is released and discharged.

  Thus, for example, the oxygen-enriched gas generated in the first adsorption cylinder 11 (that is, a dry high-concentration oxygen-concentrated gas from which moisture and nitrogen have been removed by the adsorbent) is used as the purge gas via the orifice 23 via the second adsorption cylinder. 13, the moisture is removed from the adsorbent filled in the second adsorption cylinder 13 and discharged to the outside. Similarly, the oxygen-enriched gas generated in the second adsorption cylinder 13 is supplied to the first adsorption cylinder 11 to remove moisture from the adsorbent and discharge it to the outside.

c) Next, the control process performed by the electronic control unit 41 will be described.
As shown in the flowchart of FIG. 3 and the timing chart of FIG. 4, in a state where the oxygen concentrator 1 is operating, it is determined in step 100 whether or not the power switch 47 is set to OFF. If an affirmative determination is made here, the process proceeds to step 110. If a negative determination is made, the present process is temporarily terminated.

  In step 110, since the previous stroke (see FIG. 4) after the power switch 47 is turned off is continued, the switching timing of the three-way switching valves 7 and 9 (that is, the switching timing of the intake stroke and the exhaust stroke). It is determined whether or not there is. If an affirmative determination is made here, the process proceeds to step 120, whereas if a negative determination is made, the process waits until the switching timing.

In step 120, the electromagnetic on-off valve 37 is turned on to block the flow path 35.
In the following step 130, it is determined whether or not the oxygen concentrator 1 has been operated for one cycle. If an affirmative determination is made here, the process proceeds to step 140. If a negative determination is made, the process waits until one cycle is activated. This one cycle means that, for example, the intake stroke and the exhaust stroke are completed in the first adsorption cylinder 11, that is, the exhaust stroke and the intake stroke are completed in the second adsorption cylinder 13.

Note that the pressure equalizing valve 19 is turned ON for a predetermined period (equal pressure equalizing stroke) every half cycle, and the first communication passage 17 is opened, so that the pressures of the adsorption cylinders 11 and 13 are made uniform.
In step 140, since the compressor has been operated for one cycle, the compressor 5 is stopped.

In the subsequent step 150, the open state of the pressure equalizing valve 19 is maintained longer than usual.
In the subsequent step 160, the electromagnetic on-off valve 37 is turned off to open the flow path 35, all operations are stopped, and this process is terminated.

d) Next, effects of the present embodiment having the above-described configuration will be described.
In this embodiment, when the power switch 47 is turned off, the electromagnetic on-off valve 37 is turned on to close the flow path 35, and the oxygen concentrator 1 is operated for one cycle. Then, the oxygen enriched gas generated in the first adsorption cylinder 11 is supplied as a purge gas to the second adsorption cylinder 13 through the orifice 23, and further, the oxygen enriched gas generated in the second adsorption cylinder 13 is used as the purge gas in the orifice 23. Then, the water in the adsorbent in each of the adsorption cylinders 11 and 13 is removed, and then the operation of the oxygen concentrator 1 is stopped.

  Therefore, the life of the adsorbent in both adsorption cylinders 11 and 13 can be greatly extended with a simple configuration and control in a well-balanced manner. In addition, this operation makes it possible to increase the supply amount of the purge gas from the supply amount of the oxygen-enriched gas supplied from the adsorption cylinders 11 and 13 during normal operation, and to supply the oxygen-enriched gas at a high pressure, which is effective from the adsorbent. Moisture can be removed.

  Further, in this embodiment, when an instruction to stop the operation of the oxygen concentrator 1 is given, after waiting until the switching timing of the intake or exhaust in the adsorption cylinders 11 and 13 is reached, the flow path is controlled by the electromagnetic on-off valve 37. 35 is shut off. Thereby, even if it is the structure which switches an intake stroke and an exhaust stroke for every fixed time, the pressure of oxygen concentration gas does not become excessive, and adsorption cylinders 11 and 13 which remove moisture from moderate pressure purge gas Can be supplied.

  Further, in this embodiment, when the operation of the oxygen concentrator 1 is stopped, the flow path 35 is opened by the electromagnetic on-off valve 37 after the compressor 5 is stopped. Therefore, there is an advantage that condensation does not easily occur.

  In addition, in this embodiment, when the operation of the oxygen concentrator 1 is stopped after supplying the purge gas, the pressure equalizing valve 19 is opened until the operation is stopped. The state of moisture) is made uniform.

e) Next, an experimental example performed to confirm the above-described effect will be described.
The oxygen concentrator of Example 1 was operated 31 times in an environment of an ambient temperature of 35 ° C. and an ambient humidity of 90% (relative humidity) with an operation period of 3 to 4 days and a stop period of 3 to 4 days. Repeatedly (operation for about 3000 hours), the concentration of the oxygen-enriched gas when the operation was started was measured using an inspection device (for example, an oxygen concentration meter using a limiting current type zirconia oxygen sensor). The results are shown in FIG.

Further, as a comparative example, the same experiment was performed without supplying the purge gas. The results are also shown in FIG.
As is apparent from FIG. 5, the purging as in this embodiment is suitable because the decrease in the oxygen concentration of the oxygen-enriched gas is small and the life of the adsorbent is long even if the operation time is long. .

  On the other hand, in the comparative example in which purging is not performed as in the present embodiment, if the operation time is long, the oxygen concentration of the oxygen-enriched gas decreases quickly and the life of the adsorbent is short, which is not preferable.

Next, the second embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
As shown in FIG. 6, the oxygen concentrator 51 of this embodiment includes a compressor 53, a pair of three-way switching valves (a first switching valve 55 and a second switching valve 57), and a pair of the same as in the first embodiment. An adsorption cylinder (first adsorption cylinder 59, second adsorption cylinder 61), a pressure equalizing valve 63, an orifice 65, a pair of check valves 67 and 69, a product tank 71, a pressure regulator (regulator) 73, and the like are provided.

  Particularly in this embodiment, a flow rate proportional control valve 75 (see FIG. 7) is used in place of the flow rate setting device and the electromagnetic on-off valve of the first embodiment. The flow rate proportional control valve 75 can be adjusted in its opening degree by a stepping motor 77, whereby the flow rate of oxygen-enriched gas supplied to the outside can be adjusted and the flow path 79 can be shut off.

  Also according to the present embodiment, the same effects as in the first embodiment can be obtained, and the flow rate proportional control valve 75 is used in place of the flow rate setting device and the electromagnetic on-off valve, so that there is an advantage that the device configuration can be simplified.

In addition, this invention is not limited to the said Example at all, and it cannot be overemphasized that it can implement with a various aspect in the range which does not deviate from the summary of this invention.
For example, a solenoid type flow rate proportional control valve or the like can be used as the flow rate proportional control valve.

FIG. 3 is an explanatory diagram showing a basic configuration of an oxygen concentrator of Example 1. It is explanatory drawing which shows the electrical structure of the electronic controller of the oxygen concentrator of Example 1. FIG. 3 is a flowchart illustrating processing performed by the electronic control device according to the first embodiment. 3 is a timing chart illustrating processing performed by the electronic control device according to the first embodiment. 4 is a graph showing experimental results of Example 1. It is explanatory drawing which shows the basic composition of the oxygen concentrator of Example 2. FIG. It is explanatory drawing which shows the flow rate proportional control valve used for the oxygen concentrator of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 51 ... Oxygen concentrator 5, 53 ... Compressor (air supply means)
7, 9, 55, 57 ... three-way switching valve (pressure-intensifying switching means)
11, 13, 59, 61 ... Adsorption cylinder 19, 63 ... Pressure equalizing valve 37 ... Electromagnetic on-off valve (oxygen supply cutoff means)
33 ... Flow rate setting device 23, 65 ... Orifice 75 ... Flow rate proportional control valve (Oxygen supply cutoff means)

Claims (6)

At least two adsorption cylinders filled with an adsorbent that preferentially adsorbs nitrogen over oxygen;
Air supply means for supplying and pressurizing air to the adsorption cylinder;
Pressure increase / decrease switching means for controlling pressure increase / decrease in the adsorption cylinder;
With
In the pressure fluctuation adsorption type oxygen concentrator for generating oxygen enriched gas from the air,
When instructed to stop the operation of the oxygen concentrator, it waits until the intake or exhaust switching timing in the adsorption cylinder is reached, and then shuts off the supply of the oxygen enriched gas to the outside by the oxygen supply shut-off means. And
In a state where the supply of the oxygen-enriched gas to the outside is shut off, the oxygen concentrator is operated to generate oxygen-enriched gas with at least one adsorption cylinder, and the generated oxygen-enriched gas is transferred to another adsorption cylinder An oxygen concentrator that is supplied as a purge gas to remove moisture from the adsorbent. At least two adsorption cylinders filled with an adsorbent that preferentially adsorbs nitrogen over oxygen;
Air supply means for supplying and pressurizing air to the adsorption cylinder;
Pressure increase / decrease switching means for controlling pressure increase / decrease in the adsorption cylinder;
With
In the pressure fluctuation adsorption type oxygen concentrator for generating oxygen enriched gas from the air,
When instructed to stop the operation of the oxygen concentrator, the oxygen supply shut-off means shuts off the supply of the oxygen-enriched gas to the outside, and
In a state where the supply of the oxygen-enriched gas to the outside is shut off, the oxygen concentrator is operated to generate oxygen-enriched gas with at least one adsorption cylinder, and the generated oxygen-enriched gas is transferred to another adsorption cylinder Supply as purge gas to remove moisture from the adsorbent,
Further, when the operation of the oxygen concentrator is stopped after the purge gas is supplied, until the operation is stopped, the adsorption cylinder that generates the oxygen concentrated gas and the adsorption cylinder that supplies the purge gas communicate with each other. An oxygen concentrator characterized by maintaining the valve open state . 3. The oxygen concentrator according to claim 1, wherein the purge gas is supplied by repeating the intake and exhaust strokes in the adsorption cylinder at least one cycle or more.   When stopping the operation of the oxygen concentrator after supplying the purge gas, after the operation of the air supply means is stopped, the pressurization switching means for pressurization from the air supply means to the adsorption cylinder The oxygen concentrator according to any one of claims 1 to 3, wherein the flow path is blocked. By blocking the supply to the outside of the oxygen-enriched gas by the oxygen supply interrupting means, that the supply amount of the purge gas, said to Redirecting a listen by supply of oxygen enriched gas supplied from the adsorption column during normal operation The oxygen concentrator according to any one of claims 1 to 4 , wherein the oxygen concentrator is characterized. The oxygen concentrator according to any one of claims 1 to 5 , wherein the oxygen supply cutoff means is an electromagnetic on-off valve or a flow rate proportional control valve.

Images