JP7105419B2 - Superheated steam generation system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a superheated steam generation system for heating saturated steam to generate superheated steam. In this specification, the term “superheated steam” means steam obtained by further heating steam (saturated steam) in a state of vaporization at a boiling point determined under a certain pressure under the same pressure. In the case of water at atmospheric pressure, it is water vapor heated to a boiling point exceeding 100°C.

BACKGROUND ART As an example of a superheated steam generating system and its device that heats saturated steam to generate superheated steam, there is an "atmospheric superheated steam generator" disclosed in Patent Document 1 below, for example. In this device, a bundle of a plurality of heating tubes (heating bodies) bundled so as to be in contact with each other is further covered with a cylindrical outer wall portion, and a heater is wound around the outer circumference of this outer wall portion. A temperature sensor is also attached to the outer circumference of the outer wall portion. As a result, the heat generated from the heater when energized is transmitted to the plurality of heating tubes via the outer wall portion, so that the steam passing through each heating tube can be heated. In addition, in the "superheated steam treatment apparatus" disclosed in Patent Document 2 below, a conductor pipe through which saturated steam passes is energized to heat itself, thereby enabling generation of superheated steam.

JP 2017-101910 A Japanese Unexamined Patent Application Publication No. 2017-92018

However, according to the prior art disclosed in Patent Literature 1, stainless steel is used for heating bodies such as heating tubes and thin tubes through which water vapor or the like passes. As a result, there is a problem that the product cost is increased, and it is difficult to improve the heating efficiency of water vapor or the like because the thermal conductivity is lower than that of aluminum, copper, and brass (brass). If aluminum, copper, or brass is used as the heating element, these metals are more likely to denature or soften at lower temperatures than stainless steel, so temperature control with precise timing is required. be done. However, when the temperature sensor is of the contact type, the temperature sensor itself has a heat capacity, and depending on the magnitude of the response speed, a time delay may occur in temperature control, resulting in denaturation or softening of the heating element. There is a problem of inviting. Also in the temperature control of the heater, if such a temporal delay occurs in the temperature detected by the temperature sensor, there is a problem that it is difficult to properly protect the heater.

In addition, according to the prior art disclosed in Patent Document 2, since the conductor tube itself through which saturated steam passes generates heat, the device configuration can be simplified, but the heat capacity is much larger than that of a heating wire such as a coil. Therefore, it is difficult to improve the heating efficiency, and the temperature distribution during heat generation tends to vary. is complicated. Furthermore, in order to provide a conductor pipe so as to penetrate the chamber filled with superheated steam, it is necessary to ensure both electrical insulation and airtightness. Therefore, it is difficult to select an insulating material, and the airtight structure may be complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and while it has a simple structure, it improves the heating efficiency and suppresses the denaturation and deterioration of the heating element disposed near the heating element. It aims at providing the superheated steam generation system which obtains. Another object of the present invention is to provide a superheated steam generating system capable of appropriately protecting the heater.

The superheated steam generation system of the present invention recited in claim 1 of the scope of claims is a superheated steam generation system that heats saturated steam to generate superheated steam, wherein the saturated steam is introduced to one end side and the other A cylindrical body for discharging the superheated steam from the end side, and a cladding tube accommodated in the cylindrical body and extending from the one end side to the other end side of the cylindrical body, and a heating wire that generates heat when energized is provided in the cladding tube. and a heating element disposed in the cylindrical body around the heating element, in contact with the cladding tube or in the vicinity of the cladding tube, and the saturated steam introduced into the cylindrical body enters from one end side and is heated A plurality of heating elements from which the superheated steam is emitted from the other end, a voltage sensor that detects the voltage applied to the heating wire and outputs voltage information, and a current sensor that detects the current flowing through the heating wire and outputs current information. and a controller that controls energization of the heating wire so that the heating element reaches a target temperature based on the voltage information and the current information, wherein the controller controls the voltage information and the current information at a predetermined timing. The temperature of the cladding tube is estimated using the obtained resistance value of the heating wire, the target temperature is set based on this estimated temperature, and saturated steam of a known temperature is introduced into the cylindrical body. When the heating wire is not energized, the resistance value of the heating wire obtained from the voltage information and the current information when power that does not contribute to heat generation or hardly contributes to heat generation is applied to the heating wire is measured by the cladding tube. The technical feature is that it is used for estimating or correcting the estimated temperature of
A plurality of heating elements are arranged in the cylindrical body around the heating elements and in contact with (or in the vicinity of) the cladding tube. As a result, the heat generated by the heating element is directly (or indirectly) transmitted to the plurality of heating elements arranged around the heating element. In addition, since the heating element is arranged so as to surround the heating element, compared to the configuration in which the heating element is arranged around a plurality of bundled heating elements (the configuration of Patent Document 1 above), the heating element (In the configuration of Patent Document 1, since the heating element is not arranged on the outer periphery (around) of the heating element, the heat directed to the outside of the heating element is wasted.) ). Therefore, it becomes possible to improve the heating efficiency.
In addition, the controller estimates the temperature of the cladding tube using the resistance value of the heating wire obtained from the voltage information and current information at a predetermined timing, sets the target temperature based on this estimated temperature, and sets the heating element (coating The energization of the heating wire is controlled so that the pipe) reaches this target temperature. As a result, it becomes possible to estimate the temperature of the cladding tube of the heating element and control the temperature at an appropriate timing without providing a temperature sensor. Since the heat generation of the heating wire rises relatively quickly, it is possible to perform temperature control following a sharp temperature rise in the heating element having the heating wire. In addition, since it is possible to control the temperature of the heating element in this way, it is possible to suppress denaturation and deterioration of the heating element even if the heating element is arranged in the vicinity of the periphery of the heating element (cladding tube). be possible.
Furthermore, the resistance value of the heating wire (actually measured resistance value) at a known temperature when the heating wire is not energized after saturated steam of a known temperature is introduced into the cylinder, that is, when the heating element does not generate heat, is obtained. Therefore, for example, by comparing the resistance value at the preset known temperature, it is possible to correct the error in the resistance value between the actually measured resistance value and the resistance value. As a result, for example, if the resistance value of the heating wire differs from the preset resistance value due to aged deterioration, etc., the error is corrected, so the accuracy of the temperature of the cladding tube estimated using it is also improved. improves.

In the superheated steam generating system of the present invention recited in claim 2 of the scope of claims, in the superheated steam generating system recited in claim 1 , the predetermined timing is a time when the heating wire is not energized. During the time (period) when the heating wire is energized, the voltage and current values may fluctuate due to control by the controller, making it difficult to obtain accurate voltage and current information. Therefore, for example, by acquiring the voltage information and current information output from the voltage sensor and current sensor during the period (period) when the heating element does not need to generate heat (the heating wire is not energized), the accuracy of the heating wire can be improved. It is possible to obtain an accurate resistance value, and the accuracy of the estimated cladding temperature is also improved.

Furthermore, the superheated steam generation system of the present invention as recited in claim 3 of the scope of claims is the superheated steam generation system according to claim 1 or 2 , wherein after power is turned on to the superheated steam generation system, the heating wire Before starting the energization control of the cladding tube, the resistance value of the heating wire obtained from the voltage information and the current information when power that does not contribute to heat generation or hardly contributes to heat generation is applied to the heating wire The technical feature is that it is used for estimating or correcting the estimated temperature of

After turning on the power of the superheated steam generation system, the resistance value of the heating wire (actually measured resistance value) at the ambient temperature before starting the energization control of the heating wire, that is, before the heating element heats up. By comparing the resistance value with the preset resistance value at the ambient temperature, it is possible to correct the resistance value error occurring between the actually measured resistance value. As a result, for example, if the resistance value of the heating wire differs from the preset resistance value due to aged deterioration, etc., the error is corrected, so the accuracy of the cladding temperature estimated using it is also improved. improves.

Further, the superheated steam generation system of the present invention as recited in claim 4 of the scope of claims is the superheated steam generation system according to any one of claims 1 to 3 , wherein the controller comprises a A technical feature is that PID control is used to control energization.

Since PID control is used to control the energization of the heating wire, it is possible to bring the temperature of the heating element close to the target temperature with high accuracy.

According to the first aspect of the invention, it is possible to perform temperature control of the heating element following a steep rise in temperature without providing a temperature sensor. In addition, since it is possible to control the temperature of the heating element, even if the heating element is arranged near the circumference of the heating element (the cladding tube), the temperature of the heating element exceeds the temperature of the cladding tube. Since the temperature does not increase, it is possible to suppress denaturation and deterioration of the heating element. Therefore, it is possible to improve the heating efficiency with a simple structure, and to suppress denaturation and deterioration of the heating element disposed in the vicinity of the heating element. Moreover, since it becomes possible to perform temperature control following a sharp rise in the temperature of the heating element, it is possible to appropriately protect the heater. In addition, when the temperature of the cladding tube is estimated using the resistance value of the heating element corrected at a known temperature in which the heating element does not generate heat, the accuracy of the estimated temperature of the cladding tube is improved. temperature control can be performed with high accuracy, and the denaturation and deterioration of the heating element can be suppressed more effectively. Therefore, it is possible to improve the heating efficiency with a simple structure, and to further suppress denaturation and deterioration of the heating element disposed in the vicinity of the heating element.

In the invention of claim 2 , since the accuracy of the estimated temperature of the cladding tube is improved, it is possible to perform temperature control of the heating element with high accuracy, and to further effectively suppress denaturation and deterioration of the heating element. becomes possible. Therefore, it is possible to improve the heating efficiency with a simple structure, and to further suppress denaturation and deterioration of the heating element disposed in the vicinity of the heating element.

In the third aspect of the invention, the temperature of the cladding tube is estimated using the resistance value of the heating element corrected at the ambient temperature before the heating element generates heat. , it becomes possible to control the temperature of the heating element with high accuracy, and it becomes possible to further effectively suppress the denaturation and deterioration of the heating element. Therefore, it is possible to improve the heating efficiency with a simple structure, and to further suppress denaturation and deterioration of the heating element disposed in the vicinity of the heating element.

According to the fourth aspect of the invention, the temperature of the heating element can be brought close to the target temperature with high accuracy, so that denaturation and deterioration of the heating element can be further suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the structural example of the superheated steam generation system which concerns on one Embodiment of this invention. It is a side view which shows the example of an external appearance structure of the superheated-steam generator which comprises the superheated-steam-generating system of this embodiment. FIG. 3 is an axial (longitudinal) partial cross-sectional view showing a state in which a part of the output pipe and housing of the superheated steam generator shown in FIG. 2 are cut; FIG. 4A is a cross-sectional view in the radial direction (perpendicular to the longitudinal axis) of the state cut along line IV-A-IV-A shown in FIG. 2, viewed in the direction of the arrow. FIG. 4B is an explanatory diagram showing the configuration of the cartridge heater. It is a block diagram showing a configuration example of a controller that configures the superheated steam generation system of the present embodiment. FIG. 6 is a flowchart showing an example of cartridge heater drive control processing executed by the controller shown in FIG. 5 ; FIG. FIG. 7 is a flowchart showing an example of initial temperature correction processing shown in FIG. 6 ; FIG. FIG. 4 is an explanatory diagram showing an example of a conversion map of heating wire resistance value vs. cladding tube temperature; FIG. 7 is a flow chart showing an example of correction processing at a predetermined temperature shown in FIG. 6. FIG. 7 is a flowchart showing an example of heater control processing shown in FIG. 6; FIG. 11(A) is a cross-sectional view showing a configuration example in which a heating ring is used instead of the thin tube. FIG. 11(B) is a radial cross-sectional view taken along line XI-B-XI-B shown in FIG. 11(A) and viewed in the direction of the arrow, and corresponds to FIG. 4(A). be.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a superheated steam generating system of the present invention will be described below with reference to the drawings. First, a configuration example of a superheated steam generation system 10 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a schematic diagram showing a configuration example of a superheated steam generation system 10. As shown in FIG.

As shown in FIG. 1, the superheated steam generation system 10 mainly includes a housing 11, a boiler device 12, a supply pipe 13, a relay pipe 14, a discharge pipe 15, a controller 50, a temperature sensor 17, wirings 18 and 19, superheat It is composed of the steam generator 20 and the like. For example, the housing 11 includes the boiler device 12, the supply pipe 13, the relay pipe 14, the discharge pipe 15, the controller 50, the wirings 18 and 19, It accommodates the superheated steam generator 20 and the like.

The boiler device 12 is a saturated steam generator that heats water supplied through the supply pipe 13 to generate saturated steam. Water is supplied by flowing into the introduction side end of the supply pipe 13 from a water source (not shown). The boiler device 12 includes, for example, a reservoir that stores water supplied from a supply pipe 13 at a predetermined water level or higher, and a relay pipe 14 that is connected to a space above the water surface while introducing the water stored in the reservoir. and an electric heater provided at the bottom so as to be immersed in the water in the boiler and capable of generating heat by electric power supplied from the outside.

The electric heater is electrically connected to the controller 50 via the wiring 18, and is supplied with drive power controlled by the controller 50 to heat water to 100° C. or higher (substantially under atmospheric pressure). The controller 50 controls the driving power of the electric heater based on the temperature information input from the temperature sensor 17 as will be described later. A reservoir, a boiler and an electric heater, which constitute the boiler device 12, are not shown.

The superheated steam generator 20 is a booster (auxiliary heating device) that heats saturated steam introduced from the boiler device 12 through the relay pipe 14 to generate superheated steam and discharges the superheated steam from the discharge pipe 15. That is, in the boiler device 12 , water in the boiler is boiled by supplying drive power to the electric heater to generate saturated steam, and the saturated steam is discharged to the relay pipe 14 . The superheated steam generator 20 heats the saturated steam flowing from the relay pipe 14 at, for example, 250° C. or higher to generate superheated steam.

Next, the configuration and the like of the superheated steam generator 20 will be described with reference to FIGS. 2 to 5. FIG. FIG. 2 shows a side view showing an example of the external configuration of the superheated steam generator 20. As shown in FIG. FIG. 3 also shows an axial (longitudinal) partial cross-sectional view of the superheated steam generator 20 . In FIG. 3, the body 31 and the thin tube 40 of the cartridge heater 30 are shown not in cross section but in side view. Furthermore, FIG. 4(A) shows a cross-sectional view in the radial direction (perpendicular to the longitudinal axis) of the state cut along line IV-A-IV-A shown in FIG. It is Also, FIG. 4B shows an explanatory diagram showing the configuration of the cartridge heater 30 (partially omitted in the intermediate portion). Further, FIG. 5 shows a block diagram showing a configuration example of the controller 50. As shown in FIG.

As shown in FIGS. 2 and 3, the superheated steam generator 20 is mainly composed of a housing 21, an input pipe 23, an output pipe 24, a plate 25, a packing 26, a cartridge heater 30, a thin tube 40, etc. It is attached to a predetermined position inside the housing 11 of the superheated steam generation system 10 . Note that in FIG. 1, the superheated steam generator 20 is represented by a simple rectangular symbol for convenience of illustration.

The housing 21 is, for example, a cylindrical tube made of stainless steel (hereinafter referred to as "made of stainless steel"), and has an axial length (longitudinal length) of approximately 20 cm and an axial diameter (longitudinal length in a direction orthogonal to the longitudinal axis) of approximately 20 cm. height) is set to about 2 cm. A flange portion 22a made of stainless steel and having a plate annular shape (flange shape) is welded to one end portion 21a of the housing 21 . The flange portion 22a has a diameter of, for example, about 5 cm, and has a through hole formed in its radial center portion through which the cartridge heater 30 can be inserted. Female threaded holes are formed at four locations for mating.

The other end portion 21b of the housing 21 is formed with a bottom portion 22b having a discharge hole that can communicate with the output pipe 24. As shown in FIG. The peripheral wall 21c of the housing 21 is formed with an introduction hole that communicates with the input pipe 23 on the one end 21a side.

The input pipe 23 is a cylindrical pipe made of stainless steel, and is formed, for example, so that its axial shape is L-shaped. One end of the input pipe 23 is formed with an introduction port 23a that communicates with and is connectable to the relay pipe 14, and the other end of the input pipe 23 has a peripheral wall 21c that communicates with an introduction hole of the peripheral wall 21c of the housing 21. 21c.

Like the input pipe 23, the output pipe 24 is also a stainless steel cylindrical pipe, and is formed linearly with a predetermined length, for example. One end of the output pipe 24 is formed with a discharge port 24a that can communicate and connect with the discharge pipe 15, and the other end of the output pipe 24 is a bottom portion that can communicate with the discharge hole of the bottom 22b of the housing 21. 22b. Alternatively, the other end 21b of the housing 21 may be opened without providing the bottom 22b and the output pipe 24. FIG.

The plate 25 is a flat disc made of stainless steel and has an annular shape (flange shape) like the flange portion 22a. The outer shape of the plate 25 is formed to have substantially the same shape as the flange portion 22a, but a female threaded hole that can be screwed into the tapered screw 33 of the cartridge heater 30 is formed in the center in the radial direction. The difference is that four through holes through which the bolts 27 can be inserted are formed so as to surround the .

The packing 26 is a disk-shaped sealing member with excellent heat resistance. In this embodiment, when the plate 25 is attached to the flange portion 22a of the housing 21 with four bolts 27, the packing 26 is interposed between the flange portion 22a and the plate 25. As shown in FIG. As a result, the packing 26 is brought into close contact with the flange portion 22a and the plate 25 so as to fill the gap formed therebetween, thereby increasing the airtightness between the flange portion 22a and the plate 25. As shown in FIG. The packing 26 has a through hole through which the cartridge heater 30 can be inserted and a through hole through which the bolt 27 can be inserted.

As shown in FIG. 4(B), the cartridge heater 30 includes, for example, a bobbin 32 made of magnesium oxide and a heating wire 33 such as a nichrome wire wound thereon, which is housed in a cylindrical cladding tube 35 made of stainless steel. , the cladding tube 35 is filled with an insulator 34 made of magnesium oxide. The heating wire 33 is wound around the bobbin 32 with a large diameter and high density, and both ends of the heating wire 33 (lead wires 36) are drawn out from one end of the cladding tube 35. different from the heater. Therefore, the cartridge heater 30 can generate heat at a higher temperature than the sheathed heater.

The cartridge heater 30 of this embodiment mainly includes a main body 31, a protective cover 37, a plug 38, and the like (see FIGS. 2 and 3). The cartridge heater 30 can generate heat up to 600° C., for example. Cartridge heater 30 is attached to housing 21 via plate 25 so that main body 31 is positioned substantially on the axis of housing 21 . The cartridge heater 30 is electrically connected to the controller 50 via the wiring 19, and the supply of drive power is controlled by the controller 50 as described later.

The main body 31 is formed in the shape of a long columnar rod covered with a cylindrical stainless steel cladding tube 35 that accommodates the heating wire 33 and the filled insulator 34 . In this embodiment, the length of the main body 31 is set to extend from the one end portion 21a side of the housing 21 to the other end portion 21b side. At the proximal end of the main body 31, a plug 38 covering the lead wire 36 of the heating wire 33 drawn out from the main body 31 and having a tapered screw 39 is provided.

Since the tapered thread 39 of the plug 38 can be screwed into the female thread of the female threaded hole formed in the center of the plate 25 in the radial direction, the cartridge heater can be assembled by screwing the plug 38 to the plate 25. 30 can be attached to housing 21 via plate 25 . A protective cover 37 is connected to the opposite side of the taper screw 39 of the plug 38 . The protective cover 37 covers the lead wires 36 of the heating wire 33 drawn out from the main body 31 and the connecting portions of the wires 19 connected thereto.

The narrow tube 40 is a cylindrical tube made of brass (brass), and has an axial length of about 17 cm in this embodiment. In this embodiment, when the thin tube 40 is accommodated in the housing 21, the one end 40a of the thin tube 40 is located closer to the other end 21b of the housing 21 than the introduction hole of the peripheral wall 21c communicating with the input pipe 23. Further, the axial length is set so that the other end portion 40b of the thin tube 40 is located closer to the one end portion 21a of the housing 21 than the tip of the main body 31 of the cartridge heater 30 is.

As a result, compared to the case where the one end portion 40a of the thin tube 40 is located closer to the one end portion 21a of the housing 21 than the introduction hole of the peripheral wall 21c communicating with the input pipe 23, the saturated steam flowing in from the input pipe 23 is Since it becomes easier to lead to the one end portion 40 a of the tube 40 , it is possible to reduce saturated steam passing outside the tube 40 without circulating inside the tube 40 . Therefore, the heating efficiency of saturated steam can be improved.

Further, as shown in FIG. 4A, the thin tube 40 is accommodated in the housing 21 so that its outer peripheral wall contacts the covering tube 35 of the main body 31 of the cartridge heater 30. As shown in FIG. Further, the outer peripheral wall of the thin tube 40 is housed in the housing 21 so as to contact the outer peripheral wall of the other thin tube 40 adjacent thereto. The outer peripheral wall of the thin tube 40 is also in contact with the inner peripheral surface of the peripheral wall 21 c of the housing 21 .

In this embodiment, eight thin tubes 40 are accommodated in the housing 21 so as to surround the entire periphery of the main body 31 . Although not shown, a brass rod, for example, is interposed in the gap formed between the thin tube 40 and the peripheral wall 21c. The cross section in the radial direction (the direction perpendicular to the longitudinal axis) of this rod may be circular, elliptical, rectangular, triangular, polygonal such as pentagonal, or the like. 40 is formed in a shape that is difficult to move in its radial direction. This makes it difficult for the narrow tube 40 to rattle within the housing 21, thereby suppressing the generation of noise that may occur when the superheated steam generator 20 vibrates.

As shown in FIG. 5, controller 50 is, for example, a microcomputer. Typically, it is composed of an MPU 51, a memory 53, a system bus 55, an input/output interface 57, and the like. and the supply of driving power to the cartridge heater 30 of the superheated steam generator 20 is controlled. Therefore, the input/output interface 57 is connected to the boiler device 12 via the wiring 18 and to the cartridge heater 30 via the wiring 19 . The RAM of the memory 53 has a non-volatile area that can retain stored information even when the power is turned off.

In this embodiment, for the boiler device 12, for example, the controller 50 detects whether the water in the boiler is The energization of the electric heater is controlled so that the preset temperature (for example, 100° C.) is reached. For the superheated steam generator 20, the controller 50 obtains information (voltage information and current information) on the driving power supplied to the cartridge heater 30 from the voltage sensor 71 and the current sensor 73, as will be described later. At the same time, based on these pieces of information, the energization control of the cartridge heater 30 is performed so that the preset temperature is reached. The voltage sensor 71 and current sensor 73 are provided, for example, in the middle of the wiring 19, and the voltage information and current information output from these in real time are stored in, for example, a buffer memory provided in the input/output interface 57 or the like. The latest is kept.

By configuring the superheated steam generator 20 of the superheated steam generating system 10 in this way, when the main body 31 of the cartridge heater 30 generates heat at, for example, about 300° C., the heat is transferred to a plurality of heaters arranged around the cladding tube 35 . is transmitted directly to the tubule 40 of the Therefore, the saturated steam introduced from the inlet 23a of the input pipe 23 flows into the tubes from one end 40a of these thin tubes 40 and contacts the inner peripheral wall of the thin tubes 40, whereby the heat of the cladding tube 35 is transferred through the thin tubes 40. The saturated steam is heated at, for example, 250.degree. C. to 290.degree. As a result, the steam flowing out from the other end 40b of the thin tube 40 becomes superheated steam, and the superheated steam is discharged from the outlet 24a of the output pipe 24. As shown in FIG. In addition, when the bottom portion 22b and the output pipe 24 are not provided, the superheated steam is output from the opening of the other end portion 21b of the housing 21 .

In addition, in the housing 21, the outside of the narrow tube 40 is also heat-transferred to the saturated steam when the outside of the narrow tube 40 contacts the outer peripheral wall of the narrow tube 40. , for example, is heated to around 250°C. As a result, the steam flowing out from the other end portion 40b along the outer peripheral wall of the thin tube 40 also becomes superheated steam, so that the superheated steam is discharged from the outlet 24a of the output pipe 24. FIG.

Furthermore, since the outer peripheral wall of the thin tube 40 also contacts the inner peripheral surface of the peripheral wall 21 c of the housing 21 , part of the heat generated by the main body 31 is transmitted to the peripheral wall 21 c via the thin tube 40 . Therefore, in the housing 21, the saturated steam flowing outside the narrow tube 40 contacts the inner peripheral surface of the peripheral wall 21c and is heat-transferred to the saturated steam. is heated to As a result, the steam flowing out from the other end portion 21b along the inner peripheral surface of the peripheral wall 21c of the housing 21 also becomes superheated steam, so that the superheated steam is discharged from the outlet 24a of the output pipe 24. FIG.

In this embodiment, the fine tube 40 is made of brass. This makes it possible to reduce the component cost of the thin tube 40 compared to the case where the thin tube 40 is made of stainless steel. This is because brass is generally less expensive than stainless steel and has a high thermal conductivity. In addition, it becomes possible to efficiently transfer the heat generated by the main body 31 to the narrow tube 40 and the peripheral wall 21c of the housing 21 . Although the thermal conductivity of brass depends on the distribution of copper and zinc in the mixture, it is an order of magnitude greater than that of stainless steel (16.7 to 20.9) (brass is 106). is. The unit of thermal conductivity is [W/(m·K)] (W (watt), m (meter), K (kelvin)).

By the way, brass can be denatured or softened at around 400°C. The melting temperature of brass depends on the distribution of mixed copper and zinc, and is generally around 800° C., but deterioration such as denaturation and softening can occur at lower temperatures. Therefore, in the present embodiment, the controller 50 controls the supply of drive power so that the temperature of the cladding tube 35 of the cartridge heater 30 with which the narrow tube 40 comes into contact does not exceed 350.degree.

In the superheated steam generating system 10 of this embodiment, the superheated steam generator 20 does not have a temperature sensor, as can be seen from each drawing. Therefore, in the present embodiment, the controller 50 of the superheated steam generation system 10 determines the resistance value of the heating wire 33 of the cartridge heater 30 based on the voltage information output from the voltage sensor 71 and the current information output from the current sensor 73. Further, the calculated resistance value is used to estimate the temperature of the cladding tube 35 and drive control of the cartridge heater 30 is performed. For this estimation, a predetermined conversion map (heating wire resistance vs. cladding tube temperature conversion map) stored in advance in the memory 53 of the controller 50 is used.

Here, the flow of drive control processing of the cartridge heater 30 by the controller 50 will be described with reference to FIGS. 6 to 10. FIG. FIG. 6 shows a flowchart showing an example of drive control processing of the cartridge heater 30 executed by the controller 50 . Further, FIG. 7 shows a flowchart showing an example of the initial temperature correction process shown in FIG. Further, FIG. 8 shows an explanatory diagram showing an example of a conversion map of heating wire resistance value vs. cladding tube temperature. FIG. 9 shows a flow chart showing an example of the predetermined temperature correction process shown in FIG. FIG. 10 shows a flowchart showing an example of the heater control process shown in FIG.

The drive control process shown in FIG. 6 is executed by the MPU 51 of the controller 50 after the superheated steam generation system 10 is powered on. Therefore, in this drive control process, a predetermined initialization process is first performed in step S100. In this process, for example, the work area of the RAM constituting the memory 53 of the controller 50, flags, and the like are cleared.

In subsequent step S200, an initial temperature correction process is performed. FIG. 7 shows the process flow of the initial temperature correction process in step S200, so the following description will be made with reference to FIG. In this embodiment, a predetermined conversion map is stored in the memory 53 as described above. As shown in FIG. 8, this conversion map is a "heating wire resistance vs. cladding tube temperature conversion map" that can estimate the temperature of the cladding tube 35 (horizontal axis) from the resistance value of the heating wire 33 (vertical axis). It is preset (stored (stored) in the memory 53) in the manufacturing stage of the superheated steam generating system 10, maintenance after installation, or the like.

In this initial temperature correction process, a predetermined conversion map (heating wire resistance value vs. cladding temperature conversion map). As a result, for example, when the resistance value of the heating wire 33 differs from the preset resistance value due to deterioration over time or individual differences of the heating wire 33, such an error is corrected. Instead of correcting the predetermined conversion map directly, the resistance values obtained from the predetermined conversion map may be individually corrected (they are configured to correct each time the resistance value is obtained from the predetermined conversion map). .

In this initial temperature correction process, first, a minute power output process is performed in step S201. In this process, minute electric power is output to the heating wire 33 of the cartridge heater 30 . The minute power is a power value to the extent that the heating wire 33 does not generate heat (does not contribute to heat generation), or a power value to the extent that even if the heating wire 33 generates heat, the heat is not transmitted to the cladding tube 35 (rarely contributes to heat generation). , is. For example, 10 pulses of minute current on the order of milliampere with a pulse width of 50 milliseconds are output per second. Since the heating wire 33 of the cartridge heater 30 is a resistor, the voltage value applied to the heating wire 33 is detected by the voltage sensor 71 even with such a minute power, and the current applied to the heating wire 33 is detected by the voltage sensor 71. A value is detected by the current sensor 73 .

Therefore, the voltage information (voltage value Vm) is obtained from the voltage sensor 71 and the current information (current value Im) is obtained from the current sensor 73 in subsequent step S203. More specifically, the current voltage information (voltage value Vm) and current information (voltage value Im) held in a buffer memory such as the input/output interface 57 are obtained from the buffer memory. If the information output from the voltage sensor 71 or the current sensor 73 is analog information, the information converted into digital values by an A/D converter or the like is input to the MPU 51 . As a result, the actually measured resistance value Ra (=Vm/Im) of the heating wire 33 is obtained by dividing the voltage value Vm by the current value Im in the resistance value calculation process of the next step S205.

Then, in step S206, the resistance value Rj of the heating wire 33 with respect to the ambient temperature is obtained with reference to the conversion map of the heating wire resistance value vs. the cladding tube temperature. That is, in this process, instead of estimating the temperature of the cladding tube 35 (horizontal axis) from the resistance value (vertical axis) of the heating wire 33, the resistance value Rj corresponding to the temperature is reversed from the ambient temperature of the heating wire 33. Refer to the direction (reverse lookup).

For example, if the ambient temperature of the heating wire 33 is known, the known temperature is used. The known case is a case where the ambient temperature of the superheated steam generating system 10 hardly fluctuates because the air conditioning temperature is installed in an environment where the air conditioning temperature is stable throughout the year. Further, when the ambient temperature of the heating wire 33 can fluctuate, for example, from the temperature sensor 17 of the boiler device 12, the temperature information (water temperature information) of the water before heating stored in the boiler is obtained. This is obtained and used as the ambient temperature of the heating wire 33 . Further, when a temperature sensor (not shown) is provided in the housing 21 of the superheated steam generator 20, temperature information is obtained therefrom.

In the next step S207, the difference between the measured resistance value Ra calculated in step S205 and the resistance value Rj obtained by reverse lookup in step S206 is calculated. (error) is outside the allowable range. If the error is outside the allowable range (Yes in S208), the conversion map is corrected in subsequent step S209. For correction, for example, the error is added to each resistance value stored in advance in the memory 53 (if the error is in the positive direction, the resistance value is increased, and if the error is in the negative direction, the resistance value is decreased). , each resistance value after correction is overwritten and stored in the memory 53 . Then, after completing this initial temperature correction process, the process returns to the drive control process of FIG.

For example, the broken-line curve shown in FIG. 8 is an example in which a positive error is added to each resistance value (solid-line curve) stored in advance in the memory 53 .

If the difference (error) between the two resistance values is not out of the allowable range (is within the allowable range) in the determination process of step S208 (No in S208), the conversion map of the heating wire resistance value versus the cladding tube temperature is corrected. Since it is not necessary, this initial temperature correction process is finished and the process returns to the drive control process of FIG.

Note that the measured resistance value Ra (=Vm/Im) of the heating wire 33 calculated by the resistance value calculation process in step S205 may be stored in the non-volatile area of the memory 53 in step S600 described later. As a result, for example, after the power is turned on, it is possible to leave in the memory 53 the history of the measured resistance value Ra of the heating wire 33 obtained by executing the initial temperature correction process (S200). Therefore, from this history information, it becomes possible to grasp the aging state of the measured resistance value Ra and the deterioration state of the heating wire 33 based on the aging. That is, since the degree of deterioration of the heating wire 33 can be known, it is possible to determine whether or not the cartridge heater 30 needs to be replaced, and to predict the timing of replacement and the life of the cartridge heater 30 .

As shown in FIG. 6, in step S300 of the drive control process, a predetermined temperature correction process is performed. FIG. 9 shows the process flow of the predetermined temperature correction process in step S300, so the following description will be made with reference to FIG. The predetermined temperature correction process in step S300 is similar to the initial temperature correction process described with reference to FIG.

In the predetermined temperature correction process in step S300, steam of a known temperature (for example, saturated steam of 100° C.) is introduced from the boiler device 12 into the superheated steam generator 20, and the housing 21 is filled with steam of the known temperature. The resistance value of the heating wire 33 at the known ambient temperature is actually measured.

For example, before starting the energization control of the heating wire 33, the output information from the boiler device 12 is sent to the controller 50 almost at the same time as the steam at a preset temperature is output from the boiler device 12 to the superheated steam generator 20. Since it is output, step S300 is executed with this output information as a trigger. Further, when steam of a known temperature (for example, saturated steam of 100 ° C.) is output to the superheated steam generator 20 after a predetermined time has elapsed since the electric heater of the boiler device 12 was started to be energized, this predetermined time may be triggered by the passage of If the temperature of steam output from the boiler device 12 is not set in advance, the controller 50 may acquire water temperature information output from the temperature sensor 17 of the boiler device 12 .

As a result, it is now possible to correct the preset predetermined conversion map (heating wire resistance vs. cladding tube temperature conversion map) for the known temperature. Therefore, at a known temperature, if the resistance value of the heating wire 33 differs from the preset resistance value due to aging deterioration or individual differences of the heating wire 33, such an error is corrected. Instead of correcting the predetermined conversion map directly, the resistance values obtained from the predetermined conversion map may be individually corrected (they are configured to correct each time the resistance value is obtained from the predetermined conversion map). .

In the predetermined temperature correction process, first, a minute power output process is performed in step S301. The minute electric power output to the heating wire 33 of the cartridge heater 30 is the same as in the case of the initial temperature correction process, and is a current value to the extent that the heating wire 33 does not generate heat (does not contribute to heat generation), or The current value is such that even if heat is generated, the heat is not transferred to the cladding tube 35 (it hardly contributes to heat generation). It should be noted that the minute power in the case of the correction process at the initial temperature and the minute power in the case of the correction process at the predetermined temperature can correspond to "power that does not contribute to heat generation or hardly contributes to heat generation" described in the claims. It is. Since the specific values of these minute powers are affected by the electrical specifications (resistance value, etc.) of the heating wire 33 of the cartridge heater 30, they are set in advance based on the results of individual specific experiments, computer simulations, and the like. be done.

In subsequent step S303, voltage information (voltage value Vn) is obtained from the voltage sensor 71, and current information (current value In) is obtained from the current sensor 73. FIG. More specifically, the current voltage information (voltage value Vn) and current information (voltage value In) held in a buffer memory such as the input/output interface 57 are obtained from the buffer memory. As a result, the actually measured resistance value Rb (=Vn/In) of the heating wire 33 is obtained by dividing the voltage value Vn by the current value In in the resistance value calculation process of the next step S305. Then, in step S306, the resistance value Rk of the heating wire 33 with respect to a known ambient temperature (for example, 100° C.) is obtained by reverse lookup by referring to the conversion map of the heating wire resistance value vs. the cladding tube temperature.

In the next step S307, the difference between the measured resistance value Rb calculated in step S305 and the resistance value Rk obtained by reverse lookup in step S306 is calculated. (error) is outside the allowable range. If the error is outside the allowable range (Yes in S308), the conversion map is corrected in subsequent step S309. This correction is performed in the same manner as in step S209 of the initial temperature correction process, but for example, the process may be performed such that the correction is performed for the known temperature or higher and the correction is not performed for the lower than the known temperature. . This makes it possible to leave the correction in the initial temperature correction process in step S200 for temperatures below the known temperature. When the correction is completed, each resistance value after correction is overwritten in the memory 53, and the predetermined temperature correction process is completed, and the process returns to the drive control process of FIG. If the difference (error) between the two resistance values is not out of the allowable range (it is within the allowable range) (No in S308), the predetermined temperature correction process is finished and the process returns to the drive control process of FIG.

As described above, in the drive control process executed by the controller 50 of the present embodiment, the conversion map of the heating wire resistance value versus the cladding tube temperature is used in both the initial temperature correction process in step S200 and the predetermined temperature correction process in step S300. correct. This makes it possible to improve the accuracy of the estimated temperature of the cladding tube 35 in the heater control process of step S400 described below.

In the drive control process of this embodiment, the algorithm is configured to be executed in both the correction process at the initial temperature in step S200 and the correction process at the predetermined temperature in step S300. If it is necessary to shorten the startup time of the system 10, the drive control processing algorithm may be configured to perform only one of these. Moreover, when shortening the start-up time of the superheated steam generation system 10 is given top priority, the correction process at the initial temperature in step S200 and the correction process at the predetermined temperature in step S300 may be omitted without being executed.

As shown in FIG. 6, heater control processing is performed in step S400 of the drive control processing. This heater control process is executed when saturated steam is output from the boiler device 12 and introduced into the housing 21 of the superheated steam generator 20 , and supplies drive power to the cartridge heater 30 . Therefore, when saturated steam is not output from the boiler device 12 , the controller 50 waits until the output information from the boiler device 12 is output to the controller 50 . Since the flow of the heater control process in step S400 is shown in FIG. 10, the process will be described with reference to FIG.

In this heater control process, first, a voltage/current information acquisition process is performed in step S401. The voltage information (voltage value Vr) and current information (current value Ir) output in real time from the voltage sensor 71 and the current sensor 73 and held in the buffer memory of the input/output interface 57 or the like are transferred from the buffer memory. It is a process to acquire. These pieces of information are used in the resistance value calculation process in the next step S403, and the actually measured resistance value Rr (=Vr/Ir) of the heating wire 33 is obtained by dividing the voltage value Vr by the current value Ir ( S403).

Next, cladding temperature estimation processing is performed in step S405. In this process, the current temperature of the cladding tube 35 is estimated from the measured resistance value Rr of the heating wire 33 calculated in step S403 with reference to a conversion map of heating wire resistance value vs. cladding tube temperature. For example, when the measured resistance value Rr of the heating wire 33 is 50Ω, the estimated temperature of the cladding tube 35 is about 340° C. in the corrected map (broken line curve) shown in FIG. .

Then, the estimated temperature information of the cladding tube 35 estimated at step S405 is used for the drive power control processing at step S407. In the drive power control process (S407), for example, PID control corrects the error with respect to the target temperature. If the target temperature of the cladding tube 35 is set to, for example, 380° C., the temperature of the cladding tube 35 is set to the target temperature of 380° C. based on the estimated temperature information of the cladding tube 35 estimated in step S405. The drive power supplied to the heating wire 33 is controlled so that it approaches.

By using PID control for the driving power of the heating wire 33, it is possible to bring the heating temperature of the heating wire 33 closer to the target temperature with high accuracy. In this case, the drive power control process in step S407 is not limited to PID control. For example, relatively simple on-off control (ON-OFF control), upper limit control, or proportional control may be used.

Further, in the driving power control process of step S407, a current having a pulse waveform for driving power corresponding to the AC waveform phase angle control is output to the heating wire 33. FIG. For example, at maximum power, 100 pulses are output per second when the frequency of the commercial power supply is 50 Hz, and 120 pulses are output per second when the frequency of the commercial power supply is 60 Hz. At times other than maximum power, the number of pulses output is less than these (100 or 120 pulses). Moreover, such a pulse is not output at the time of minimum power. In other words, the supply of drive power is stopped. During the period of the heater control process (S400), drive power having such a pulsed current waveform is generally output except when the supply of drive power is suspended.

During the period in which the driving power is supplied to the cartridge heater 30, the current value of the heating wire 33 fluctuates except when the maximum power is supplied. hard. For this reason, for example, when the power is not at maximum power, the pulse current for measuring the resistance value is generated by detecting the period in which the pulse current waveform is not output (including at the time of minimum power). output on line 33; In addition, a period in which the pulse-shaped current waveform is not output is forcibly provided, for example, every second, and a pulse current for measuring the resistance value is output to the heating wire 33 during that period. During such a period, for example, only one pulse of a minute current of milliampere order with a pulse width of 5 milliseconds is output. As a result, the accuracy of the resistance value of the heating wire 33 calculated in S403 using the voltage information and current information acquired in step S401 is improved. Accuracy can also be improved.

Further, for example, the supply of drive power for causing the heating wire 33 to generate heat is suspended for a predetermined period. This predetermined period is the time (for example, 3 seconds) required for the heating wire 33 of the cartridge heater 30 to reach approximately the same temperature as the cladding tube 35 . By measuring the resistance value of the heating wire 33 during such a predetermined period, the cartridge heater 30 can function as a temperature sensor for detecting the temperature of the cladding tube 35 . For example, during the predetermined period, similar to the minute power output processing (S201, S301) described above, the heating wire 33 is supplied with a minute current of milliampere order with a pulse width of 50 milliseconds (the resistance value of the heating wire 33 10 pulses per second are output. As a result, the accuracy of the resistance value of the heating wire 33 calculated in S403 using the voltage information and current information acquired in step S401 is further improved. accuracy can be further improved.

During the period in which driving power is supplied to the cartridge heater 30, the temperature of the heating wire 33 rises due to heat generation, such as when the power is at maximum power, and the temperature of the heating wire 33 continues to change. and the temperature of the cladding tube 35 may differ. This is because the thermal resistance of the insulator 34 interposed between the heating wire 33 and the cladding tube 35 has an effect. Therefore, during the period when the temperature of the heating wire 33 is rising (for example, during the period after the start of supply of the drive power until the temperature of the cladding tube 35 reaches a predetermined temperature (near the target temperature) below the target temperature) , the temperature of the cladding tube 35 is obtained by subtracting the temperature of the heat resistance of the insulator 34 from the temperature of the heating wire 33 (S405). The temperature of the heating wire 33 is estimated using a conversion map of the heating wire resistance value versus the heating wire temperature (not shown) which is configured like the conversion map shown in FIG. 8 and stored in the memory 53 . In addition, during the period when the temperature of the heating wire 33 is rising, for example, by counting down a preset timer counter value by timer processing (not shown), the elapsed time from the start of supply of driving power is measured. .

The period during which the pulse-shaped current waveform is not output and the predetermined period during which the supply of driving power for heating the heating wire 33 is suspended corresponds to the "predetermined timing" described in the claims. It is possible.

The heater control process in step S400 is continuously performed until power-off information is input in step S500 (No in S500). When it is determined in step S500 that the power-off information has been input (Yes in S500), the control information (for example, the maximum temperature information of the cladding tube 35 and the heating wire resistance value versus cladding tube correction history of the temperature conversion map, etc.) is stored in the non-volatile area of the RAM of the memory 53 by the control information storage processing in step S600, and this drive control processing ends.

In the drive control process shown in FIG. 6, the repeat loop of the heater control process (S400) when the determination result of the determination process of step S500 is "No" is performed at intervals of, for example, two minutes as accurate timing. The process flow may be configured as shown. That is, in this case, it takes two minutes after the heater control process (S400) is performed until the heater control process (S400) is performed again. Therefore, for example, the voltage/current information acquisition process (S401), the resistance value calculation process (S403), and the cladding temperature estimation process (S405) are performed within a period of about 3 seconds, and the remaining period of about 1 minute 57 seconds. In this case, the drive power control process (S407) and the determination process of S600 are performed. This makes it possible to estimate the temperature of the cladding tube 35 and control the temperature every two minutes, which is an accurate timing.

Further, the repetition time of the heater control process (S400) that is repeated by such a loop process may be configured to be automatically changed according to the operating conditions of the superheated steam generation system 10. For example, when the heater control process (S400) of the cartridge heater 30 is started for the first time after the superheated steam generation system 10 is powered on (immediately after the heating wire 33 starts to generate heat), the heater control process (S400) is repeated. Set the time to about several seconds to 10 seconds, and set the repetition time of the heater control process (S400) to about 2 minutes to 5 minutes after 30 minutes have passed after the power is turned on (after the heat generation of the heating wire 33 is stabilized). configured to As a result, for example, immediately after the heating wire 33 starts to generate heat, it is possible to perform temperature control that follows the sharp temperature rise of the heating wire 33, and after the heat generation of the heating wire 33 stabilizes, noise It is possible to suppress unnecessary temperature control caused by disturbances such as

As described above, in the superheated steam generating system 10 of the present embodiment, the plurality of capillaries 40 are arranged inside the housing 21 around the main body 31 of the cartridge heater 30 in contact with the cladding tube 35 . As a result, the heat generated by the heat generated by the main body 31 is directly transmitted to the plurality of thin tubes 40 arranged around the main body 31 (cladding tube 35). In addition, since the thin tubes 40 are arranged so as to surround the main body 31, compared to the configuration in which the main body 31 is arranged around a plurality of bundled thin tubes 40 (the configuration of Patent Document 1 above), the heating element The heat that spreads outward is effectively utilized. Therefore, since the heating efficiency is improved, it is possible to significantly reduce the size of the apparatus as compared with the configuration of Patent Document 1. In other words, since the size of the device is significantly reduced, the diffusion of heat that does not contribute to heating of the narrow tube 40 is suppressed, and the heating efficiency is improved, compared to a case of a large size. Therefore, it is possible to heat the saturated steam flowing through the plurality of capillaries 40 with a simple configuration.

In addition, the controller 50 estimates the temperature of the cladding tube 35 using the resistance value of the heating wire 33 obtained from the voltage information of the voltage sensor 71 and the current information of the current sensor 73 at a predetermined timing, and based on this estimated temperature A target temperature is set, and energization of the heating wire 33 is controlled so that the cladding tube 35 of the main body 31 of the cartridge heater 30 reaches this target temperature. As a result, the temperature of the cladding tube 35 of the main body 31 can be estimated and the temperature can be controlled at appropriate timing without providing a temperature sensor. Since the heating wire 33 such as a nichrome wire generates heat relatively quickly, the main body 31 having the heating wire 33 can perform temperature control following a steep temperature rise. Moreover, since the temperature control of the main body 31 becomes possible, it is possible to suppress denaturation and deterioration of the thin tubes 40 even when the thin tubes 40 are arranged in the vicinity of the periphery of the main body 31 or the like.

Therefore, in the superheated steam generation system 10 of the present embodiment, the heating efficiency of the superheated steam generator 20 is improved with a simple configuration, and the thin tubes 40 arranged near the main body 31 of the cartridge heater 30 are modified. and deterioration can be suppressed. For example, even if the plurality of thin tubes 40 arranged around the cartridge heater 30 are made of brass, the temperature of the covering tube 35 of the cartridge heater 30 with which these thin tubes 40 come into contact is controlled to, for example, 400° C. or less. It becomes possible to suppress the deterioration of the thin tube 40 made of brass. In other words, it is possible to use a brass pipe, which is inexpensive in terms of cost and has high thermal conductivity, as the thin tube 40 .

In addition, in the superheated steam generator 20 of the superheated steam generating system 10 of the above-described embodiment, a configuration in which a plurality of thin tubes 40 are arranged around the main body 31 so as to be in contact with the cladding tube 35 of the cartridge heater 30 is adopted. A configuration may be adopted in which a plurality of capillaries 40 are arranged in the vicinity of the cladding tube 35 without being in direct contact with the tube 35 . In this configuration, compared to a configuration in which a plurality of narrow tubes 40 are arranged so as to be in contact with the cladding tube 35, the heat generated by the heat generated by the main body 31 is distributed around the main body 31 (the cladding tube 35). The thermal resistance between the cladding tube 35 and the thin tubes 40 increases because the heat is indirectly transmitted to the plurality of thin tubes 40 that are formed. Therefore, although the heating efficiency of the saturated steam is reduced, it is possible to increase the diameter of the circumference on which the capillaries 40 can be arranged. It becomes possible to improve.

Further, in the superheated steam generator 20 of the superheated steam generation system 10 of the above-described embodiment, the thin tube 40 is made of brass (brass), but if it is a material that is cheaper than stainless steel, for example, aluminum It may be made of other metallic material such as or non-metallic material.

Note that the thin tube 40 may be made of stainless steel. Although the cost of the tubules themselves increases compared to when these tubules are made of brass, in this embodiment, the tubules 40 are arranged so as to surround the entire periphery of the cladding tube 35 of the cartridge heater 30. there is As a result, compared to the configuration of the perimeter heater type of Patent Document 1, the heat that spreads to the outside of the main body 31 (the cladding tube 35) is effectively utilized. Therefore, since the heating efficiency is improved, it is possible to significantly reduce the size of the apparatus as compared with the configuration of Patent Document 1. In other words, since the size of the device is significantly reduced, the diffusion of heat that does not contribute to heating of the narrow tube 40 is suppressed, and the heating efficiency is improved, compared to a case of a large size.

Therefore, as compared with the configuration of Patent Document 1, the size of the device is reduced, which leads to a reduction in product cost because the necessary metal materials and the like are reduced. Also, even if the narrow tube 40 is made of stainless steel, the device configuration can be simplified, and the accompanying reduction in the number of parts makes it possible to reduce the product cost.

In addition, by making the thin tubes 40 made of stainless steel, it becomes possible to heat these thin tubes to the maximum exothermic temperature of the cartridge heater 30 (for example, 600°C). It is possible to generate superheated steam at a temperature close to . By keeping the heat generation temperature of the cartridge heater 30 low (for example, 300° C.), it is also possible to extend the life of the stainless steel narrow tube 40 .

Furthermore, in the superheated steam generator 20 of the superheated steam generating system 10 of the above-described embodiment, the housing 21 is composed of a cylindrical tube (cylindrical tube), but the shape of the radial cross section of the tube is limited to a circular shape. Instead, for example, it may be formed in an arbitrary shape such as a polygonal shape such as a square shape, a pentagonal shape, or a hexagonal shape, or a deformed circular shape such as an elliptical shape or an oval (oval) shape. In addition, although the thin tube 40 is also configured by a cylindrical tube (cylindrical tube), the shape of the radial cross section of the tube is not limited to a circle, and may be polygonal such as a square, pentagonal, or hexagonal shape. It may be formed in an arbitrary shape such as an elliptical shape, a deformed circular shape such as an elliptical (oval) shape, or the like.

Instead of the narrow tube 40, for example, a round wire with a circular cross-section or a flat wire with a rectangular cross-section wound in a helical shape (coil shape) may be used as the heating element. Further, as shown in FIG. 11, a plurality of heating rings 140 each having a finely sliced thin tube 40 (in the axial direction) may be arranged around the cartridge heater 30 . FIG. 11(A) shows a cross-sectional view showing a configuration example in which a heating ring 140 is used in place of the narrow tube 40. As shown in FIG. Further, FIG. 11(B) shows a radial cross-sectional view taken along line XI-B-XI-B shown in FIG. 11(A) and viewed in the direction of the arrow.

The heating ring 140 is made of brass, for example, and has an axial length of about 3 mm in this embodiment. In this embodiment, eight heating rings 140 are arranged around the cladding tube 35 of the cartridge heater 30, and the outer peripheral walls of these heating rings 140 are in contact with the outer peripheral walls of other adjacent heating rings 140. is provided in Further, in this embodiment, the eight heating rings 140 arranged in this way are arranged at equal intervals in the axial direction of the cladding tube 35 between the one end 21a and the other end 21b of the housing 21. .

As a result, the saturated steam introduced from the input pipe 23 flows in from one end 140a of the heating ring 140, comes into contact with the inner peripheral wall of the heating ring 140, and then flows out from the other end 140b. Heat is transferred to the saturated steam via the heating ring 140 . Therefore, while the saturated steam passes through the plurality of heating rings 140 from one end 21a of the housing 21 to the other end 21b, such heat transfer is repeated, and the saturated steam is transferred to the capillaries 40. As in the case above, it is heated at, for example, 250° C. to 290° C. and discharged as superheated steam from the output pipe 24 or the other end 21b.

Further, in the housing 21 , heat is also transferred to the saturated steam when the outside of the heating ring 140 is in contact with the outer peripheral wall of the heating ring 140 . The peripheral wall is heated to, for example, around 250°C. As a result, the steam flowing along the outer peripheral wall of the heating ring 140 to the other end 21b of the housing 21 also becomes superheated steam, and the superheated steam is discharged from the output pipe 24 and the other end 21b.

Furthermore, since the outer peripheral wall of heating ring 140 also contacts the inner peripheral surface of peripheral wall 21 c of housing 21 , part of the heat generated by main body 31 is transmitted to peripheral wall 21 c via heating ring 140 . Therefore, in the housing 21, the saturated steam flowing outside the heating ring 140 contacts the inner peripheral surface of the peripheral wall 21c and is heat-transferred to the saturated steam. heated back and forth. As a result, the steam flowing out from the other end portion 21b along the inner peripheral surface of the peripheral wall 21c of the housing 21 also becomes superheated steam, so that the superheated steam is discharged from the output pipe 24 and the other end portion 21b.

Instead of such a plurality of heating rings 140, fins made of strip-shaped brass plates are spirally wound around the main body 31 (cladding tube 35) of the cartridge heater 30 so as to protrude from the main body 31 (cladding tube 35) in the radial direction. may That is, a strip-shaped brass fin is wound around the main body 31 (cladding tube 35) from one end side to the other end side of the cartridge heater 30 like a blade of a spiral boring machine. As a result, the saturated steam introduced from the input pipe 23 flows from one end 21a to the other end 21b of the housing 21 while being in contact with both the front and back surfaces of the fins, thereby dissipating the heat of the cladding tube 35. Heat is transferred to the saturated steam through the fins. Therefore, the saturated steam is heated at, for example, 250° C. to 290° C. and discharged from the output pipe 24 or the other end 21b as superheated steam, as in the case of the narrow tube 40. FIG.

The "heating body" described in the claims is a structure capable of transferring the heat of the cladding tube 35 to the saturated steam, and the saturated steam can flow from one end 21a of the housing 21 to the other end 21b. It is not limited to the narrow tube 40, the heating ring 140, or such fins as long as they can form a sufficient gap. , a thread ball or lump of brass wire (metal wire) tangled like a metal scrubbing brush may be used. They may also be made of stainless steel.

Further, in the superheated steam generator 20 of the superheated steam generating system 10 of the above-described embodiment, the main body 31 of the cartridge heater 30 is configured to be positioned substantially on the axis of the housing 21 (cylindrical body). The body 31 of the cartridge heater 30 may be positioned off-axis. Further, when a plurality of cartridge heaters 30 are used, for example, the other cartridge heaters 30 may be arranged so that the bodies 31 of the other cartridge heaters 30 are positioned on the circumference on which the thin tubes 40 are arranged. .

Furthermore, the two housings 21 are connected in the radial direction so that the cartridge heaters are placed substantially on the axis of each housing 21 like the cross-sectional shape of the feeder line in the radial direction (the direction perpendicular to the longitudinal axis) of the spectacle feeder. A configuration in which the body 31 of 30 is arranged may be adopted. This makes it possible to heat the thin tubes 40, the heating rings 140, etc. by the two cartridge heaters 30, and also increases the number of the thin tubes 40, the heating rings 140, etc., thereby greatly increasing the flow rate of the saturated steam. It becomes possible to increase the amount of superheated steam generated.

In addition, in the above-described embodiment and other configuration examples, the case of the cartridge heater 30 was described as an example of the heating element. A sheathed heater, for example, may be used as long as it is a heating element that can be arranged so as to surround the .

In the above-described embodiment and other configuration examples, the temperature of the cladding tube 35 of the cartridge heater 30 is estimated and the control system is configured so that the temperature of the cladding tube 35 becomes the target temperature. The control system may be configured such that the temperature is estimated and the heat generation temperature of the heating wire 33 becomes the target temperature. This makes it possible to prevent the heating wire 33 from generating heat to a temperature significantly exceeding the target temperature. In addition, since the time delay is very small compared to the case of detecting the heat generation temperature of the heat generating wire 33 using a contact type temperature sensor, temperature control is performed following the sharp temperature rise of the heat generating wire 33. Thus, the cartridge heater 30 can be properly protected.

Further, in the above-described embodiments and other configuration examples, as minute power, for example, 10 pulses of milliampere-order minute current with a pulse width of 50 milliseconds are output per second, or 10 milliampere-order minute currents with a pulse width of 5 milliseconds are output. Although only one pulse of minute current is output, it is not limited to this as long as the current of the pulse waveform for driving is not output to the heating wire 33, for example, micro order or milliampere order. A minute current may be flowed through the heating wire 33 continuously over time. In this case, the voltage value and the current value are detected multiple times by the voltage sensor 71 and the current sensor 73 during the period in which the minute current is continuously applied, and the average value is obtained by acquiring multiple pieces of voltage information and current information. , median, mode, etc. can be obtained by predetermined statistical processing. Therefore, the accuracy of calculating the resistance value of the heating wire 33 can be improved, and the accuracy of the estimated temperature of the cladding tube 35 estimated using such a resistance value can be further improved.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications or changes of the above-described specific examples. In addition, the technical elements described in this specification or in the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as filed. Furthermore, the techniques exemplified in this specification or drawings achieve a plurality of purposes at the same time, and achieving one of them has technical utility in itself. It should be noted that descriptions in parentheses in the [Description of Reference Symbols] column can clearly indicate the correspondence relationship between the terms used in each of the above-described embodiments and the terms described in the scope of claims.

DESCRIPTION OF SYMBOLS 10... Superheated steam generation system 11... Case 12... Boiler apparatus 17... Temperature sensor 20... Superheated steam generator 21... Housing (cylindrical body)
30 Cartridge heater 31 Main body (heating element)
33... Heating wire 35... Coating tube 40... Thin tube (heating body)
40a... One end (one end side)
40b... other end (other end side)
50... Controller 71... Voltage sensor 73... Current sensor 140... Heating ring (heating body)
140a... One end (one end side)
140b... other end (other end side)

Claims (4)

A superheated steam generation system that heats saturated steam to generate superheated steam,
a cylindrical body that introduces the saturated steam to one end side and discharges the superheated steam from the other end side;
a heating element that is housed in the cylindrical body and has a cladding tube that extends from the one end side of the cylindrical body to the other end side of the cladding tube, and that has a heating wire that generates heat when energized in the cladding tube;
The superheated steam is placed in the cylindrical body around the heating element, in contact with the cladding tube or in the vicinity of the cladding tube, and the saturated steam introduced into the cylindrical body enters from one end side and is heated. a plurality of heating elements emanating from an end side;
A voltage sensor that detects the voltage applied to the heating wire and outputs voltage information;
a current sensor that detects the current flowing through the heating wire and outputs current information;
a controller that controls energization of the heating wire so that the heating element reaches a target temperature based on the voltage information and the current information;
The controller estimates the temperature of the cladding tube using the resistance value of the heating wire obtained from the voltage information and the current information at a predetermined timing, sets the target temperature based on the estimated temperature, and When the heating wire is not energized after saturated steam of a known temperature is introduced into the cylinder, the voltage information and the current when power that does not contribute to heat generation or hardly contributes to heat generation is applied to the heating wire. A superheated steam generating system, wherein the resistance value of the heating wire obtained from the information is used for estimating or correcting the estimated temperature of the cladding tube. 2. The superheated steam generating system according to claim 1 , wherein the predetermined timing is a time when the heating wire is not energized. After the superheated steam generation system is powered on and before the energization control of the heating wire is started, the voltage information and the current information when power that does not contribute to heat generation or hardly contributes to heat generation is applied to the heating wire. 3. The superheated steam generating system according to claim 1, wherein the obtained resistance value of the heating wire is used for estimating or correcting the estimated temperature of the cladding tube. The superheated steam generating system according to any one of claims 1 to 3 , wherein the controller uses PID control to control energization of the heating wire.

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