Gas composition regulator

Abstract

The gas composition regulating device includes an adsorber, an air supply pump (310), and an exhaust pump (320). The gas composition regulating device performs a pressurizing action and a decompressing action. In the pressurizing action, the air supply pump (310) supplies air to the adsorber, and in the decompressing action, the exhaust pump (320) exhausts air from the adsorber. The air supply pump (310) and the exhaust pump (320) are respectively positive displacement pumps and have sealing components (313, 323). The main components of the sealing component (323) of the exhaust pump (320) are fluororesin and fibrous carbon material.

Description

Technical Field

[0001] The present disclosure relates to a gas composition regulating device. Background Art

[0002] Patent Document 1 discloses an oxygen concentrator. This oxygen concentrator is a gas composition adjustment device that adopts a so-called PSA (Pressure Swing Adsorption) method.

[0003] The oxygen concentrator of Patent Document 1 includes an adsorption cylinder filled with an adsorbent. The oxygen concentrator performs a pressurization operation and a decompression operation. In the pressurization operation, an air supply pump supplies air (atmosphere) to the adsorption cylinder so that the adsorbent adsorbs nitrogen in the air. In the decompression operation, an exhaust pump draws gas from the adsorption cylinder so that nitrogen is desorbed from the adsorbent.

[0004] During the pressurization operation, the adsorbent in the adsorption cylinder adsorbs nitrogen in the air, and oxygen-rich gas flows out of the adsorption cylinder. Oxygen-rich gas is a gas with a higher oxygen concentration and a lower nitrogen concentration than the atmosphere. During the decompression operation, nitrogen-rich gas, which is mainly composed of nitrogen desorbed from the adsorbent in the adsorption cylinder, is sucked out from the adsorption cylinder by the exhaust pump. Nitrogen-rich gas is a gas with a higher nitrogen concentration and a lower oxygen concentration than the atmosphere.

[0005] The oxygen concentrator in Patent Document 1 includes an air pump that integrates an air supply pump and an exhaust pump. The air supply pump and the exhaust pump are respectively positive displacement pumps that include a cylinder, a piston, and a sealing component. The sealing component is mounted on the piston to seal the gap between the cylinder and the piston.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2013 / 042557 Summary of the invention

[0009] -Technical problem to be solved by the invention-

[0010] In a gas composition regulating device having a positive displacement pump, a sealing member mounted on a piston slides on a cylinder. Therefore, the sealing member gradually wears. When the wear amount of the sealing member exceeds a certain level, the amount of gas leaking from the gap between the cylinder and the piston increases. As a result, the amount of oxygen-rich gas and nitrogen generated decreases, and the performance of the gas composition regulating device decreases.

[0011] The purpose of the present disclosure is to extend the life of sealing components and improve the reliability of a gas composition regulating device.

[0012] -Technical solutions to solve technical problems-

[0013] A first aspect of the present disclosure relates to a gas composition regulating device 100, which includes adsorbers 234, 235, an air supply pump 310 and an exhaust pump 320, wherein the adsorbers 234, 235 have an adsorbent for adsorbing at least one component in a treated gas, the air supply pump 310 supplies the treated gas to the adsorbers 234, 235, the exhaust pump 320 sucks out gas from the adsorbers 234, 235, and the gas composition regulating device 100 performs a pressurizing action and a decompressing action, in which the treated gas pressurized by the air supply pump 310 is supplied to the adsorbers 234, 235, and the gas flowing out of the adsorbers 234, 235 is used as a first pressure regulating action. A gas is delivered. In the decompression action, the exhaust pump 320 sucks gas from the adsorber 234, 235 and ejects it, and the gas ejected by the exhaust pump 320 is delivered as the second gas. The air supply pump 310 and the exhaust pump 320 are respectively positive displacement pumps including cylinders 311, 321, pistons 312, 322 and sealing components 313, 323. The pistons 312, 322 are accommodated in the cylinders 311, 321. The sealing components 313, 323 are installed on the pistons 312, 322 and seal the gaps between the cylinders 311, 321 and the pistons 312, 322. The main components of the sealing component 323 of the exhaust pump 320 are fluororesin and fibrous carbon material.

[0014] In the exhaust pump 320 of the first aspect, when the sealing member 323 slides on the cylinder 321, the fibrous carbon material is exposed on the surface of the sealing member 323 and contacts the cylinder 321. Since the fibrous carbon material has an elongated shape, it is difficult for the sealing member 323 to fall off even if it contacts the cylinder 321. The sealing member 323, which is mainly composed of the fibrous carbon material, is difficult to wear because the wear reduction effect brought by the fibrous carbon material lasts for a long time. Therefore, in this aspect, the life of the sealing member 323 of the exhaust pump 320 is extended, and the reliability of the gas composition adjustment device 100 is improved.

[0015] According to a second aspect of the present disclosure, based on the first aspect, main components of the sealing member 313 of the air supply pump 310 are fluororesin and granular carbon material.

[0016] In the second aspect, the sealing member 313 having fluororesin and granular carbon material as main components is provided on the air supply pump 310 .

[0017] According to a third aspect of the present disclosure, based on the first or second aspect, a linear expansion coefficient of the sealing component 313 of the air supply pump 310 is smaller than a linear expansion coefficient of the sealing component 323 of the air exhaust pump 320 .

[0018] The greater the thermal expansion of the sealing members 313 and 323, the greater the force pressing the sealing members 313 and 323 against the cylinders 311 and 321, and the greater the wear of the sealing members 313 and 323. In addition, the temperature of the air supply pump 310 is generally higher than that of the exhaust pump 320.

[0019] In the third aspect, the linear expansion coefficient of the sealing member 313 of the air supply pump 310 is smaller than the linear expansion coefficient of the sealing member 323 of the exhaust pump 320. Therefore, compared with the case where the linear expansion coefficient of the sealing member 313 of the air supply pump 310 and the linear expansion coefficient of the sealing member 323 of the exhaust pump 320 are equal, the amount of thermal expansion of the sealing member 313 becomes smaller in the air supply pump 310 having a higher temperature than the exhaust pump 320. As a result, in the air supply pump 310 of this aspect, the force that presses the sealing member 313 against the cylinder 311 becomes smaller, and the life of the sealing member 313 is extended.

[0020] According to a fourth aspect of the present disclosure, based on any one of the first to third aspects, the Young's modulus of the sealing member 313 of the air supply pump 310 is greater than the Young's modulus of the sealing member 323 of the air exhaust pump 320 .

[0021] The greater the deformation of the sealing members 313 and 323 due to the gas pressure, the greater the force that pushes the sealing members 313 and 323 onto the cylinders 311 and 321, and the greater the wear of the sealing members 313 and 323. In addition, the gas pressure acting on the sealing member 313 of the air supply pump 310 is generally higher than the gas pressure acting on the sealing member 323 of the exhaust pump 320.

[0022] In the fourth aspect, the Young's modulus of the sealing member 313 of the air supply pump 310 is larger than the Young's modulus of the sealing member 323 of the exhaust pump 320. Therefore, compared with the case where the Young's modulus of the sealing member 313 of the air supply pump 310 and the Young's modulus of the sealing member 323 of the exhaust pump 320 are equal, the amount of deformation of the sealing member 313 due to the gas pressure in the air supply pump 310 becomes smaller. As a result, in the air supply pump 310 of this aspect, the force that presses the sealing member 313 against the cylinder 311 becomes smaller, and the life of the sealing member 313 is extended.

[0023] The fifth aspect of the present disclosure is based on any one of the first to fourth aspects mentioned above, wherein the treated gas is atmospheric air, the adsorbent of the adsorber 234, 235 adsorbs nitrogen which is a component of the treated gas, the first gas has a lower nitrogen concentration and a higher oxygen concentration than the treated gas, the second gas has a higher nitrogen concentration and a lower oxygen concentration than the treated gas, and the gas composition regulating device operates to supply the second gas to the storage room 2 for storing fresh food.

[0024] In the fifth aspect, the gas composition control device 100 generates the first gas and the second gas by processing the atmosphere as the processed gas. The gas composition control device 100 of this aspect supplies the second gas having a higher nitrogen concentration and a lower oxygen concentration than the atmosphere to the storage 2 storing fresh food.

[0025] The sixth aspect of the present disclosure is based on any one of the first to fourth aspects mentioned above, wherein the treated gas is atmosphere, the adsorbent of the adsorber adsorbs nitrogen which is a component of the treated gas, the first gas has a lower nitrogen concentration and a higher oxygen concentration than the treated gas, the second gas has a higher nitrogen concentration and a lower oxygen concentration than the treated gas, and the gas composition regulating device operates to supply the first gas to a user.

[0026] In the sixth aspect, the gas composition adjusting device 100 generates the first gas and the second gas by treating the atmosphere as the treated gas. The gas composition adjusting device 100 of this aspect supplies the first gas having a lower nitrogen concentration and a higher oxygen concentration than the atmosphere to the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a perspective view of a transport refrigeration device provided with a gas composition regulating device according to a first embodiment;

[0028] Figure 2 is a schematic longitudinal cross-sectional view of a transport refrigeration device provided with a gas composition regulating device according to a first embodiment and a transport container provided with the transport refrigeration device;

[0029] Figure 3 is a piping system diagram showing the structure of the gas composition adjusting device of the first embodiment;

[0030] Figure 4 This is a diagram showing the equivalent of the gas composition regulating device performing the first action. Figure 3 's picture;

[0031] Figure 5 This is the equivalent of showing the gas composition adjustment device performing the second action. Figure 3 's picture;

[0032] Figure 6 is a perspective view of an air pump included in the gas composition regulating device;

[0033] Figure 7 is a top view of an air pump included in the gas composition regulating device;

[0034] Figure 8 is an exploded perspective view of an air pump included in the gas composition regulating device;

[0035] Fig. 9 is a simplified cross-sectional view of an air supply pump included in the air pump;

[0036] Fig.10 is a simplified cross-sectional view of an exhaust pump included in the air pump;

[0037] Fig.11 is a cross-sectional view schematically showing a contact portion between an air seal and a cylinder;

[0038] Fig.12 is a graph showing the temporal changes in the suction side pressure and the discharge side pressure of each of the air supply pump and the exhaust pump;

[0039] Fig.13 It is a piping system diagram showing the structure of the gas composition adjusting device according to the second embodiment. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0041] (First Embodiment)

[0042] The gas composition adjusting device of the first embodiment is provided in a transport refrigeration device 10. The transport refrigeration device 10 is provided in a transport container 1.

[0043] The transport container 1 is a refrigerated container (refrigerated container) capable of managing the temperature inside the container. The transport container 1 is used to transport fresh food (such as fruits, vegetables, flowers, etc.), wherein the fresh food breathes and absorbs oxygen (O 2 ) and releases carbon dioxide (CO 2 ).

[0044] like Figure 1 As shown, the transport container 1 includes a container body 2 and a transport refrigeration device 10. The transport container 1 is used for marine transportation. The transport container 1 is transported by marine transportation vehicles such as ships.

[0045] -Container body-

[0046] The container body 2 is a storage room for storing the above-mentioned fresh food.

[0047] The container body 2 is formed in a hollow box shape. The container body 2 is formed to be long in the horizontal direction. An opening is formed at one end of the container body 2 in the longitudinal direction. The opening of the container body 2 is sealed by a transport refrigeration device 10. A storage space 5 for storing transported objects is formed in the container body 2.

[0048] - Transport Refrigeration Units -

[0049] The transport refrigeration device 10 is installed at the opening of the container body 2. The transport refrigeration device 10 includes a housing 11 and a refrigerant circuit. The transport refrigeration device 10 adjusts the temperature of the air in the storage space 5 (the air in the box).

[0050] <Housing>

[0051] like Figure 2 As shown, the housing 11 includes a partition wall 12 and a partition plate 15 .

[0052] An in-tank flow path 20 is formed inside the partition wall 12. An out-tank chamber 25 is formed outside the partition wall 12. The in-tank flow path 20 and the out-tank chamber 25 are partitioned by the partition wall 12.

[0053] The partition wall 12 includes an outer wall 13 and an inner wall 14. The outer wall 13 is located outside the container body 2. The inner wall 14 is located inside the container body 2.

[0054] The outer wall 13 seals the opening of the container body 2. The outer wall 13 is installed at the peripheral edge of the opening of the container body 2. The lower part of the outer wall 13 bulges toward the inside of the container body 2. The outer chamber 25 is formed inside the bulged outer wall 13.

[0055] The box inner wall 14 is opposite to the box outer wall 13. The box inner wall 14 has a shape extending along the box outer wall 13. The box inner wall 14 is arranged with a gap between it and the box outer wall 13. A heat insulating material 16 is provided between the box inner wall 14 and the box outer wall 13.

[0056] The partition 15 is arranged at a position closer to the inside of the container body 2 than the box inner wall 14. An in-box flow path 20 is formed between the partition 12 and the partition 15. An inlet 21 is formed between the upper end of the partition 15 and the top plate of the container body 2. An outlet 22 is formed between the lower end of the partition 15 and the lower end of the partition 12. The in-box flow path 20 is formed from the inlet 21 to the outlet 22.

[0057] <Essential components of the refrigerant circuit>

[0058] The refrigerant circuit is a closed circuit filled with refrigerant. The refrigerant circuit circulates the refrigerant to perform a vapor compression refrigeration cycle. The refrigerant circuit includes a compressor 31, an external heat exchanger 32, an internal heat exchanger 60, and a refrigerant pipe connecting these components.

[0059] The compressor 31 is arranged at the lower part of the outer chamber 25. The outer heat exchanger 32 is arranged at the upper part of the outer chamber 25. The outer heat exchanger 32 is a fin-tube type heat exchanger, which exchanges heat between the refrigerant and the air outside the box. The shape of the outer heat exchanger 32 is a cylindrical shape that is approximately rectangular. The inner heat exchanger 60 is arranged in the inner flow path 20. The inner heat exchanger 60 is a fin-tube type heat exchanger, which exchanges heat between the refrigerant and the air inside the box.

[0060] <External fan>

[0061] The transport refrigeration device 10 includes an external fan 34. The external fan 34 is a propeller fan. The external fan 34 is arranged in the external chamber 25. In addition, the external fan 34 is arranged inside the external heat exchanger 32 formed in a cylindrical shape. The external fan 34 delivers external air to the external heat exchanger 32.

[0062] <In-box fan>

[0063] The transport refrigeration device 10 includes two in-box fans 35. The in-box fans 35 are propeller fans. The in-box fans 35 are arranged in the in-box flow path 20. In addition, the in-box fans 35 are arranged above the in-box heat exchanger 60. The in-box fans 35 deliver the in-box air to the in-box heat exchanger 60.

[0064] <Heater>

[0065] The transport refrigeration device 10 includes a heater 65. The heater 65 is arranged below the in-box heat exchanger 60. The heater 65 is used to melt frost attached to the in-box heat exchanger 60.

[0066] <Electronic component box>

[0067] like Figure 1 As shown, the transport refrigeration device 10 has an electronic component box 36. The electronic component box 36 is arranged in the upper part of the outer chamber 25. The electronic component box 36 contains electrical components such as a frequency conversion board and a control board.

[0068] - Operation of transport refrigeration equipment -

[0069] The basic operation of the transport refrigeration device 10 is described. When the transport refrigeration device 10 is in operation, the compressor 31, the external fan 34, and the internal fan 35 are in operation, and a refrigeration cycle is performed in the refrigerant circuit. In the refrigerant circuit, the external heat exchanger 32 functions as a condenser, and the internal heat exchanger 60 functions as an evaporator. In the external heat exchanger 32, the refrigerant releases heat to the air outside the box and condenses. In the internal heat exchanger 60, the refrigerant absorbs heat from the air inside the box and evaporates. As a result, the internal heat exchanger 60 cools the air inside the box.

[0070] The air in the container body 2 circulates in the storage space 5 and the in-box flow path 20. The air in the box flowing in the in-box flow path 20 is cooled by the in-box heat exchanger 60. The air in the box cooled by the in-box heat exchanger 60 is supplied to the storage space 5 through the outlet 22. In this way, the air in the storage space 5 is cooled, and the temperature of the air in the box is maintained at a predetermined target temperature.

[0071] - Gas composition adjustment device -

[0072] Next, the gas composition adjusting device 100 according to the present embodiment will be described.

[0073] The gas composition adjusting device 100 is provided in the transport refrigeration device 10 for so-called CA (Controlled Atmosphere) transport. The gas composition adjusting device 100 adjusts the composition of the air in the storage space 5 of the transport container 1 (specifically, the concentrations of nitrogen, oxygen, and carbon dioxide) to be different from the composition of the atmosphere.

[0074] like Figure 3 As shown, the gas composition regulating device 100 includes a filter unit 220, a main unit 200, a sensor unit 160, a ventilation exhaust pipe 150, and a controller 110. The gas composition regulating device 100 uses the so-called PSA (Pressure Swing Adsorption) method to separate the air outside the box (atmosphere) as the treated gas into a nitrogen-rich gas having a higher nitrogen concentration than the atmosphere and a lower oxygen concentration than the atmosphere and an oxygen-rich gas having a lower nitrogen concentration than the atmosphere and a higher oxygen concentration than the atmosphere. The nitrogen-rich gas is the second gas. The oxygen-rich gas is the first gas.

[0075] <Filter unit, external air pipe>

[0076] The filter unit 220 is a box-shaped component. The filter unit 220 is disposed in the outer chamber 25 of the transport refrigeration device 10. The filter unit 220 includes an air filter 221. The air filter 221 is a filter for capturing dust and salt contained in the air outside the box. The air filter 221 of this embodiment is a membrane filter having air permeability and waterproofness.

[0077] The filter unit 220 is connected to the main unit 200 via an external air pipe 241. One end of the external air pipe 241 is connected to the filter unit 220. The other end of the external air pipe 241 is connected to an air pump 300 described later. The external air pipe 241 guides the air outside the box (atmosphere) after passing through the air filter 221 to the air pump 300 as a processed gas.

[0078] <Main unit>

[0079] The main unit 200 is disposed in the outer chamber 25 of the transport refrigeration device 10. The main unit 200 includes an air pump 300, a first adsorption cylinder 234, a second adsorption cylinder 235, a first switching valve 232, a second switching valve 233, and a unit housing 201 that accommodates these components. In addition, the unit housing 201 is provided with an inlet pipe 242, a suction pipe 243, a first outflow pipe 244, and a second outflow pipe 245.

[0080] <Air Pump>

[0081] The air pump 300 includes an air supply pump 310, an exhaust pump 320 and a drive motor 302. The air supply pump 310 and the exhaust pump 320 suck and eject air respectively. The air supply pump 310 and the exhaust pump 320 are connected to a drive shaft of a drive motor 302. In the air pump 300, the air supply pump 310 and the exhaust pump 320 are driven by a drive motor 302.

[0082] The other end of the external air pipe 241 is connected to the suction port of the air supply pump 310. One end of the introduction pipe 242 is connected to the discharge port of the air supply pump 310. The air supply pump 310 supplies the treated gas sucked from the external air pipe 241 to the first adsorption cylinder 234 and the second adsorption cylinder 235 through the introduction pipe 242.

[0083] The suction port of the exhaust pump 320 is connected to a suction pipe 243. The discharge port of the exhaust pump 320 is connected to a first outflow pipe 244. The exhaust pump 320 supplies the gas sucked from the first adsorption cylinder 234 and the second adsorption cylinder 235 through the suction pipe 243 to the storage space 5 of the container body 2 through the first outflow pipe 244.

[0084] <Inlet pipe>

[0085] The inlet pipe 242 is a pipe for guiding the treated gas ejected from the air supply pump 310 to the first adsorption cylinder 234 and the second adsorption cylinder 235. One end of the inlet pipe 242 is connected to the ejection port of the air supply pump 310. The inlet pipe 242 is branched into two branch pipes at the other end thereof, one branch pipe is connected to the first switching valve 232, and the other branch pipe is connected to the second switching valve 233.

[0086] <Suction tube>

[0087] The suction pipe 243 is a pipe that guides the gas flowing out of the first adsorption cylinder 234 and the second adsorption cylinder 235 to the exhaust pump 320. One end of the suction pipe 243 is connected to the suction port of the exhaust pump 320. The suction pipe 243 is branched into two branch pipes at its other end, one branch pipe is connected to the first switching valve 232, and the other branch pipe is connected to the second switching valve 233.

[0088] <First outflow pipe>

[0089] The first outflow pipe 244 is a pipe for guiding the gas ejected from the exhaust pump 320 to the in-box flow path 20. One end of the first outflow pipe 244 is connected to the ejection port of the exhaust pump 320. The other end of the first outflow pipe 244 opens toward the downstream side of the in-box fan 35 in the in-box flow path 20.

[0090] A check valve 264 and a supply-side switch valve 273 are provided in sequence from one end of the first outflow pipe 244 toward the other end. The check valve 264 allows air to flow only in a direction from one end of the first outflow pipe 244 toward the other end, and prevents air from flowing in the opposite direction. The supply-side switch valve 273 is a switch valve composed of a solenoid valve.

[0091] <Switch valve>

[0092] The first switching valve 232 and the second switching valve 233 are switching valves having three valve ports. The first switching valve 232 and the second switching valve 233 are respectively configured to switch between a first state in which the first valve port is connected to the second valve port and disconnected from the third valve port, and a second state in which the first valve port is connected to the third valve port and disconnected from the second valve port.

[0093] The first valve port of the first switching valve 232 is connected to one end of the first adsorption cylinder 234. In addition, a branch pipe of the introduction pipe 242 is connected to the second valve port of the first switching valve 232, and a branch pipe of the suction pipe 243 is connected to the third valve port of the first switching valve 232. The first switching valve 232 switches the first adsorption cylinder 234 between a state connected to the air supply pump 310 and a state connected to the exhaust pump 320.

[0094] The first valve port of the second switching valve 233 is connected to one end of the second adsorption cylinder 235. In addition, a branch pipe of the introduction pipe 242 is connected to the second valve port of the second switching valve 233, and a branch pipe of the suction pipe 243 is connected to the third valve port of the second switching valve 233. The second switching valve 233 switches the second adsorption cylinder 235 between a state connected to the air supply pump 310 and a state connected to the exhaust pump 320.

[0095] <Adsorption cylinder>

[0096] The first adsorption cylinder 234 and the second adsorption cylinder 235 are components including a cylindrical container with both ends closed and an adsorbent filled in the container. Each of the adsorption cylinders 234 and 235 is an adsorber including an adsorbent.

[0097] The adsorbent filled in the adsorption cylinders 234 and 235 has the following properties: it adsorbs nitrogen and water (water vapor) in the gas to be processed under a pressurized state at a pressure higher than the atmospheric pressure, and desorbs nitrogen and water under a reduced pressure state at a pressure lower than the atmospheric pressure. As an example of an adsorbent having the above properties, zeolite can be cited, which is a porous body having micropores whose pore diameter is smaller than the molecular diameter of nitrogen molecules (3.0 angstroms) and larger than the molecular diameter of oxygen molecules (2.8 angstroms). The adsorbent set in the adsorption cylinders 234 and 235 adsorbs nitrogen and water (water vapor) as components of the gas to be processed.

[0098] <Second outflow pipe>

[0099] The second outflow pipe 245 is branched into two branch pipes at one end thereof, one branch pipe is connected to the other end of the first adsorption cylinder 234, and the other branch pipe is connected to the other end of the second adsorption cylinder 235. A check valve 261 is provided on each branch pipe of the second outflow pipe 245. Each check valve 261 allows air to flow in the direction of outflow from the corresponding adsorption cylinder 234, 235, and prevents air from flowing in the opposite direction.

[0100] The second outflow pipe 245 extends to the outside of the unit housing 201. The other end of the second outflow pipe 245 opens toward the outer chamber 25 of the transport container 1. A check valve 262 and an orifice plate 263 are provided at the confluence portion of the second outflow pipe 245. The check valve 262 is arranged at a position close to the other end side of the second outflow pipe 245 relative to the orifice plate 263. The check valve 262 allows air to flow toward the other end of the second outflow pipe 245 and prevents air from flowing in the opposite direction.

[0101] <Release tube>

[0102] A release pipe 250 is connected to each branch pipe of the second outflow pipe 245. One end of the release pipe 250 is connected to the branch pipe connected to the first adsorption cylinder 234, and the other end is connected to the branch pipe connected to the second adsorption cylinder 235. One end of the release pipe 250 is connected between the first adsorption cylinder 234 and the check valve 261. The other end of the release pipe 250 is connected between the second adsorption cylinder 235 and the check valve 261.

[0103] A release valve 251 is provided on the release pipe 250. The release valve 251 is an on-off valve composed of a solenoid valve. When the first adsorption cylinder 234 and the second adsorption cylinder 235 are pressure-equalized, the release valve 251 is opened. In addition, an orifice plate 252 is provided on each side of the release valve 251 on the release pipe 250.

[0104] <Exhaust connection pipe>

[0105] An exhaust connection pipe 271 is connected to the first outlet pipe 244. One end of the exhaust connection pipe 271 is connected to the first outlet pipe 244, and the other end is connected to the second outlet pipe 245. One end of the exhaust connection pipe 271 is connected to the first outlet pipe 244 at a position between the exhaust pump 320 and the check valve 264. The other end of the exhaust connection pipe 271 is connected to the second outlet pipe 245 at a position closer to the outside of the box than the check valve 262.

[0106] The exhaust connection pipe 271 is provided with an exhaust on-off valve 272. The exhaust on-off valve 272 is an on-off valve composed of a solenoid valve. When the air flowing through the first outflow pipe 244 is exhausted to the outside of the box, the exhaust on-off valve 272 is opened.

[0107] <Measurement pipe>

[0108] A measuring pipe 281 is connected to the first outflow pipe 244. The measuring pipe 281 is a pipe for connecting the first outflow pipe 244 to the sensor unit 160. One end of the measuring pipe 281 is connected to the first outflow pipe 244 at a position between the check valve 264 and the supply-side switching valve 273. The other end of the measuring pipe 281 is connected to the sensor unit 160.

[0109] The measuring pipe 281 is provided with a measuring on-off valve 282. The measuring on-off valve 282 is an on-off valve composed of a solenoid valve. When the air flowing through the first outflow pipe 244 is sent to the sensor unit 160, the measuring on-off valve 282 is opened.

[0110] <Bypass pipe>

[0111] A bypass connection pipe 255 is connected to the inlet pipe 242. The bypass connection pipe 255 is a pipe for allowing the air outside the box to bypass the first adsorption cylinder 234 and the second adsorption cylinder 235 and supply the air outside the box to the storage space 5 of the transport container 1. One end of the bypass connection pipe 255 is connected between the branch of the inlet pipe 242 and the air supply pump 310. The other end of the bypass connection pipe 255 is connected between one end of the measurement pipe 281 and the measurement switch valve 282.

[0112] The bypass connecting pipe 255 is provided with a bypass switch valve 256. The bypass switch valve 256 is a switch valve composed of a solenoid valve. When the air outside the box ejected by the air supply pump 310 is supplied to the storage space 5 without changing the composition of the air outside the box, the bypass switch valve 256 is opened.

[0113] <Sensor unit>

[0114] The sensor unit 160 includes an oxygen sensor 161 , a carbon dioxide sensor 162 , and a sensor housing 163 .

[0115] The oxygen sensor 161 is, for example, a zirconia current sensor that measures the oxygen concentration in a mixed gas such as air. The carbon dioxide sensor 162 is, for example, a non-dispersive infrared (NDIR) sensor that measures the carbon dioxide concentration in a mixed gas such as air. The oxygen sensor 161 and the carbon dioxide sensor 162 are housed in a sensor housing 163.

[0116] The sensor housing 163 is a box-shaped member. The sensor housing 163 includes an air filter 164. The air filter 164 is a membrane filter for capturing dust and the like contained in the air in the box. The air filter 164 filters the air in the box that flows into the sensor housing 163.

[0117] The sensor housing 163 is connected to a measuring pipe 281. The sensor housing 163 is also connected to an outlet pipe 165. The outlet pipe 165 has an inlet end connected to the sensor housing 163 and an outlet end opening upstream of the in-tank fan 35 in the in-tank flow path 20.

[0118] When the measuring switch valve 282 is closed, the air in the box flows inside the sensor housing 163. Specifically, the air in the box flowing in the box flow path 20 flows into the sensor housing 163 through the air filter 164, flows through the outlet pipe 165 after passing through the sensor housing 163, and then flows into the suction side of the box fan 35 in the box flow path 20. Therefore, when the measuring switch valve 282 is closed, the oxygen sensor 161 measures the oxygen concentration of the air in the box, and the carbon dioxide sensor 162 measures the carbon dioxide concentration of the air in the box.

[0119] When the measuring switch valve 282 is open, the gas flowing through the measuring pipe 281 flows inside the sensor housing 163. Specifically, the gas flowing in the first outflow pipe 244 or the bypass connection pipe 255 flows into the sensor housing 163 through the measuring pipe 281, then flows through the outlet pipe 165 after passing through the sensor housing 163, and then flows into the suction side of the in-box fan 35 in the in-box flow path 20. Therefore, when the measuring switch valve 282 is open, the oxygen sensor 161 measures the oxygen concentration of the gas flowing from the measuring pipe 281 into the sensor housing 163, and the carbon dioxide sensor 162 measures the carbon dioxide concentration of the gas flowing from the measuring pipe 281 into the sensor housing 163.

[0120] <Exhaust pipe for ventilation>

[0121] The ventilation exhaust pipe 150 is a pipe for exhausting the air in the transport container 1 to the space outside the container. The ventilation exhaust pipe 150 passes through the partition wall 12 of the transport refrigeration unit 10. The ventilation exhaust pipe 150 is provided with a ventilation exhaust valve 151. The ventilation exhaust valve 151 is an on-off valve composed of a solenoid valve.

[0122] <Controller>

[0123] The controller 110 includes a microcomputer 111 mounted on a control substrate and a storage device 112 storing software for operating the microcomputer 111. The storage device 112 is a semiconductor memory.

[0124] The controller 110 controls the components of the gas composition adjusting device 100. The measured values ​​of the oxygen sensor 161 and the carbon dioxide sensor 162 are input to the controller 110. The controller 110 controls the air pump 300, the first switching valve 136, and the second switching valve 137. The controller 110 also controls the ventilation exhaust valve 151, the release valve 251, the bypass switch valve 256, the exhaust switch valve 272, the supply side switch valve 273, and the measurement switch valve 282.

[0125] - Operation of the gas composition adjustment device -

[0126] The gas composition adjusting device 100 adjusts the composition of the air in the storage space 5 of the transport container 1 (in this embodiment, the oxygen concentration and the carbon dioxide concentration of the air in the box). Here, the operation of the gas composition adjusting device 100 is described by taking the case where the target range of the oxygen concentration of the air in the box is 5%±1% and the target range of the carbon dioxide concentration of the air in the box is 2%±1% as an example.

[0127] The gas composition regulating device 100 of this embodiment performs a regulating operation to reduce the oxygen concentration and carbon dioxide concentration of the air in the box in the storage space 5, and performs an external air introduction operation to increase the oxygen concentration of the air in the box in the storage space 5. In the regulating operation, the gas composition regulating device 100 supplies nitrogen-rich gas generated from the air outside the box (atmosphere) as the treated gas to the storage space 5. In the external air introduction operation, the gas composition regulating device 100 directly supplies the air outside the box (atmosphere) to the storage space 5.

[0128] The controller 110 of the gas composition adjusting device 100 determines whether to start or stop the adjusting operation, and whether to start or stop the external air introduction operation based on the measurement values ​​of the oxygen sensor 161 and the carbon dioxide sensor 162.

[0129] When the cargo 6 is loaded into the transport container 1, the composition of the air in the storage space 5 is substantially the same as the composition of the atmosphere (nitrogen concentration: 78%, oxygen concentration: 21%, carbon dioxide concentration: 0.04%). Therefore, the gas composition regulating device 100 performs regulating operation to reduce the oxygen concentration of the air in the box. When the oxygen concentration of the air in the box reaches the upper limit value (6%) of the target range, the gas composition regulating device 100 stops regulating operation.

[0130] When the oxygen concentration of the air in the box reaches 6% and the regulating operation of the gas composition regulating device 100 is stopped, the oxygen concentration of the air in the box gradually decreases because the fresh food stored in the storage space 5 will breathe, and the carbon dioxide concentration of the air in the box gradually increases.

[0131] When the carbon dioxide concentration of the air in the box reaches the upper limit value (3%) of the target range, the gas composition regulating device 100 performs regulating operation to reduce the carbon dioxide concentration of the air in the box. When the carbon dioxide concentration of the air in the box reaches the lower limit value (1%) of the target range, the gas composition regulating device 100 stops regulating operation.

[0132] When the oxygen concentration of the air in the box reaches the lower limit value (4%) of the target range, the gas composition regulating device 100 starts the operation of introducing external air to increase the oxygen concentration of the air in the box. When the oxygen concentration of the air in the box reaches the upper limit value (6%) of the target range, the gas composition regulating device 100 stops the operation of introducing external air.

[0133] In this way, the gas composition regulating device 100 performs regulating operation to reduce the oxygen concentration of the air in the box in the storage space 5 from 21% (oxygen concentration of the atmosphere) to the target range. In addition, the gas composition regulating device 100 repeatedly performs regulating operation and external air introduction operation to maintain the oxygen concentration and carbon dioxide concentration of the air in the box in the storage space 5 within their respective target ranges.

[0134] - Adjustment operation of gas composition adjustment device -

[0135] During the adjustment operation, the gas composition adjustment device 100 separates the air outside the box (atmosphere) as the treated gas into nitrogen-rich gas and oxygen-rich gas, and supplies the nitrogen-rich gas to the storage space 5, and discharges the oxygen-rich gas to the space outside the box. In addition, during the adjustment operation, the ventilation exhaust valve 151 is in an open state, and the air in the box is discharged to the space outside the box through the ventilation exhaust pipe 150.

[0136] In the adjustment operation, the flow rate of the nitrogen-rich gas supplied to the storage space 5 by the gas composition adjustment device 100 is greater than the flow rate of the air in the box discharged from the storage space 5 by the gas composition adjustment device 100. Therefore, the storage space 5 is maintained at a positive pressure.

[0137] During the adjustment operation, the gas composition adjustment device 100 alternately repeats the first operation and the second operation every predetermined switching time Ts. The switching time Ts is set to 14 seconds, for example. The controller 110 controls the first switching valve 232 and the second switching valve 233 so that the first operation and the second operation are alternately performed.

[0138] <First Action>

[0139] like Figure 4 As shown, in the first action, the first switching valve 232 is set to the first state, and the second switching valve 233 is set to the second state. In addition, in the first action, the supply side switch valve 273 is opened, and the remaining switch valves 251, 256, 272, and 282 are closed. In addition, in the first action, the air pump 300 is operated, and a pressurizing action is performed on the first adsorption cylinder 234 and a decompressing action is performed on the second adsorption cylinder 235.

[0140] The air supply pump 310 sucks in the treated gas from the external air pipe 241 and pressurizes it, and supplies the pressurized treated gas to the first adsorption cylinder 234. In the first adsorption cylinder 234, nitrogen and water (water vapor) contained in the supplied treated gas are adsorbed by the adsorbent. As a result, in the first adsorption cylinder 234, an oxygen-rich gas having a lower nitrogen concentration than the treated gas and a higher oxygen concentration than the treated gas is generated. After the oxygen-rich gas flows out of the first adsorption cylinder 234 and flows through the second outflow pipe 245, it is discharged to the space outside the box.

[0141] On the other hand, the exhaust pump 320 draws gas from the second adsorption cylinder 235. In the second adsorption cylinder 235, the internal pressure decreases, and nitrogen and water are desorbed from the adsorbent. As a result, a nitrogen-rich gas having a higher nitrogen concentration than the treated gas and a lower oxygen concentration than the treated gas is generated in the second adsorption cylinder 235. The nitrogen-rich gas flows from the second adsorption cylinder 235 into the suction pipe 243 and is sucked into the exhaust pump 320. The exhaust pump 320 pressurizes the sucked nitrogen-rich gas and ejects the pressurized nitrogen-rich gas toward the first outlet pipe 244. The nitrogen-rich gas is supplied to the flow path 20 in the box through the first outlet pipe 244.

[0142] <Second Action>

[0143] like Figure 5 As shown, in the second action, the first switching valve 232 is set to the second state, and the second switching valve 233 is set to the first state. In addition, in the second action, the supply-side switch valve 273 is opened, and the remaining switch valves 251, 256, 272, and 282 are closed. In addition, in the second action, the air pump 300 is operated, and a decompression action is performed on the first adsorption cylinder 234 and a pressurization action is performed on the second adsorption cylinder 235.

[0144] The air supply pump 310 sucks the treated gas from the external air pipe 241 and pressurizes it, and supplies the pressurized treated gas to the second adsorption cylinder 235. In the second adsorption cylinder 235, nitrogen and water (water vapor) contained in the supplied treated gas are adsorbed by the adsorbent. As a result, in the second adsorption cylinder 235, an oxygen-rich gas having a lower nitrogen concentration than the treated gas and a higher oxygen concentration than the treated gas is generated. The oxygen-rich gas flows out of the second adsorption cylinder 235 and flows through the second outflow pipe 245, and is discharged to the space outside the box.

[0145] On the other hand, the exhaust pump 320 draws gas from the first adsorption cylinder 234. In the first adsorption cylinder 234, the internal pressure decreases, and nitrogen and water are desorbed from the adsorbent. As a result, a nitrogen-rich gas having a higher nitrogen concentration than the treated gas and a lower oxygen concentration than the treated gas is generated in the first adsorption cylinder 234. The nitrogen-rich gas flows from the first adsorption cylinder 234 into the suction pipe 243 and is sucked into the exhaust pump 320. The exhaust pump 320 pressurizes the sucked nitrogen-rich gas and ejects the pressurized nitrogen-rich gas toward the first outlet pipe 244. The nitrogen-rich gas is supplied to the flow path 20 in the box through the first outlet pipe 244.

[0146] - Air Pump -

[0147] The air pump 300 is described in detail. As described above, the air pump 300 includes an air supply pump 310 and an exhaust pump 320. The air supply pump 310 and the exhaust pump 320 are respectively positive displacement pumps. In addition, the air supply pump 310 and the exhaust pump 320 are respectively oil-free pumps that do not use lubricating oil.

[0148] like Figure 6 to Figure 8 As shown, the air pump 300 includes a crankcase 301 and a drive motor 302. In addition, the air pump 300 includes two air supply side cylinders 311, two air supply side pistons 312, two exhaust side cylinders 321 and two exhaust side pistons 322. It should be noted that the "upper", "lower", "right", "left", "front" and "rear" described in the description of the air pump 300 respectively represent Figure 6 The direction shown (specifically, the direction when the air pump 300 is viewed from the front).

[0149] The crankcase 301 is a member formed in a quadrangular prism shape. A crankshaft (not shown) is housed in the crankcase 301. The drive motor 302 is mounted on the lower end of the crankcase 301. The drive motor 302 is connected to the crankshaft to drive the crankshaft.

[0150] <Air supply pump>

[0151] In the air pump 300, two air supply side cylinders 311 and two air supply side pistons 312 constitute an air supply pump 310. One air supply side cylinder 311 is paired with one air supply side piston 312. The other air supply side cylinder 311 is paired with the other air supply side piston 312.

[0152] The air supply side cylinder 311 is a short cylindrical component. Figure 7 As shown, a supply side cylinder 311 is respectively installed on the right side and the left side of the crankcase 301. The base end of the supply side cylinder 311 is tightly connected to the side surface of the crankcase 301.

[0153] A cylinder head 315 and a cylinder head cover 316 are mounted on each air supply side cylinder 311. The cylinder head 315 is a square plate-shaped component. The cylinder head 315 is configured to seal the top end of the air supply side cylinder 311. A suction port 315a and a discharge port 315b are formed on the cylinder head 315. The cylinder head cover 316 is a square plate-shaped component. The cylinder head cover 316 is configured to cover the cylinder head 315.

[0154] like Figure 8 and Fig. 9 As shown, each air supply side piston 312 is accommodated in the corresponding air supply side cylinder 311. In addition, each air supply side piston 312 is connected to the crankshaft. When the crankshaft rotates, each air supply side piston 312 reciprocates along the axial direction of the corresponding air supply side cylinder 311.

[0155] like Fig. 9 As shown, the air supply side piston 312 includes a piston body 312 a , a rod 312 b , an air supply side air seal 313 , and a seal fixing plate 314 .

[0156] The piston body 312a is a metal member formed in a disk shape. The rod 312b is a rod-shaped metal member. The rod 312b is formed integrally with the piston body 312a. The rod 312b is connected to the crankshaft.

[0157] The air seal 313 on the air supply side is a flexible annular component. The outer peripheral edge of the air seal 313 on the air supply side is bent toward the cylinder head 315 side over the entire circumference. The air seal 313 on the air supply side is a sealing component. The air seal 313 on the air supply side seals the gap between the piston body 312a and the inner wall surface of the air supply side cylinder 311 to maintain the air tightness of the gas chamber 317.

[0158] The seal fixing plate 314 is a metal member formed in a disk shape and is fixed to the piston body 312a by bolts or the like, and sandwiches the air supply side air seal 313 between the seal fixing plate 314 and the piston body 312a.

[0159] In the air supply pump 310, the internal space of the air supply side cylinder 311 is divided into a gas chamber 317 on the cylinder head 315 side and a back pressure chamber 318 on the crankcase 301 side by the piston body 312a of the air supply side piston 312. When the air supply side piston 312 reciprocates, gas is sucked into the gas chamber 317 from the suction port 315a, and the gas in the gas chamber 317 is ejected from the ejection port 315b.

[0160] <Exhaust pump>

[0161] In the air pump 300, two exhaust-side cylinders 321 and two exhaust-side pistons 322 constitute an exhaust pump 320. One exhaust-side cylinder 321 is paired with one exhaust-side piston 322. The other exhaust-side cylinder 321 is paired with the other exhaust-side piston 322.

[0162] The exhaust side cylinder 321 is a short cylindrical component. Figure 7 As shown, an exhaust side cylinder 321 is respectively installed on the front side and the rear side of the crankcase 301. The base end of the exhaust side cylinder 321 is tightly connected to the side of the crankcase 301.

[0163] A cylinder head 325 and a cylinder head cover 326 are mounted on each exhaust side cylinder 321. The cylinder head 325 is a square plate-shaped member. The cylinder head 325 is configured to seal the top end of the exhaust side cylinder 321. A suction port 325a and a discharge port 325b are formed on the cylinder head 325. The cylinder head cover 326 is a square plate-shaped member. The cylinder head cover 326 is configured to cover the cylinder head 325.

[0164] like Figure 8 and Fig.10 As shown, each exhaust side piston 322 is accommodated in the corresponding exhaust side cylinder 321. In addition, each exhaust side piston 322 is connected to the crankshaft. When the crankshaft rotates, each exhaust side piston 322 reciprocates along the axial direction of the corresponding exhaust side cylinder 321.

[0165] like Fig.10 As shown, the exhaust side piston 322 includes a piston body 322 a , a rod 322 b , an exhaust side air seal 323 , and a seal fixing plate 324 .

[0166] The piston body 322a is a metal member formed in a disk shape. The rod 322b is a rod-shaped metal member. The rod 322b is formed integrally with the piston body 322a. The rod 322b is connected to the crankshaft.

[0167] The exhaust side air seal 323 is a flexible annular member. The outer peripheral edge of the exhaust side air seal 323 is bent toward the exhaust side piston 322 side over the entire circumference. The exhaust side air seal 323 is a sealing member. The exhaust side air seal 323 seals the gap between the piston body 322a and the inner wall surface of the exhaust side cylinder 321 to maintain the airtightness of the gas chamber 327.

[0168] The seal fixing plate 324 is a metal member formed in a disk shape and is fixed to the piston body 322a by bolts or the like, and the exhaust side air seal 323 is sandwiched between the seal fixing plate 324 and the piston body 322a.

[0169] In the exhaust pump 320, the internal space of the exhaust side cylinder 321 is divided into a gas chamber 327 on the cylinder head 325 side and a back pressure chamber 328 on the crankcase 301 side by the piston body 322a of the exhaust side piston 322. When the exhaust side piston 322 reciprocates, gas is sucked into the gas chamber 327 from the suction port 325a, and the gas in the gas chamber 327 is ejected from the ejection port 325b.

[0170] <Material and characteristics of air seals>

[0171] The main components of the air seal 313 on the air supply side are fluororesin and granular carbon material. The fluororesin constituting the air seal 313 on the air supply side is PTFE (polytetrafluoroethylene). The granular carbon material constituting the air seal 313 on the air supply side is granular carbon with an average particle size of about 35nm. In the air seal 313 on the air supply side, the mass ratio of PTFE is 75%, and the mass ratio of granular carbon material is 23%. The radial linear expansion coefficient of the air seal 313 on the air supply side is 7.7×10 -5 [1 / °C]. The Young's modulus of the air supply side air seal 313 is 0.67 [GPa] at a temperature of 75°C.

[0172] The main components of the exhaust side air seal 323 are fluororesin and fibrous carbon material. The fluororesin constituting the exhaust side air seal 323 is PTFE (polytetrafluoroethylene). The diameter of the fibrous carbon material constituting the exhaust side air seal 323 is approximately 5μm to 15μm, and the length is approximately 20μm to 30μm. In the exhaust side air seal 323, the mass ratio of PTFE is 90%, and the mass ratio of the fibrous carbon material is 10%. The radial linear expansion coefficient of the exhaust side air seal 323 is 9.3×10 -5 [1 / °C]. The Young's modulus of the exhaust-side air seal 323 is 0.52 [GPa] at a temperature of 75°C.

[0173] - Wear of air seals -

[0174] <Air supply side air seal>

[0175] like Fig. 9 As shown, in the air supply pump 310 , the outer peripheral edge portion of the air supply side air seal 313 slides on the inner wall surface of the air supply side cylinder 311 .

[0176] During the operation of the air supply pump 310, the pressure of the gas chamber 317 is higher than the pressure of the back pressure chamber 318. Therefore, the outer peripheral edge of the air seal 313 on the air supply side is pushed open by the gas pressure of the gas chamber 317 and is pushed against the inner wall surface of the air cylinder 311 on the air supply side. In addition, during the operation of the air supply pump 310, the temperature of the air cylinder 311 on the air supply side reaches about 80°C, and the temperature of the air seal 313 on the air supply side is also close to 80°C. Therefore, during the operation of the air supply pump 310, the air seal 313 on the air supply side is thermally expanded, and thereby the outer peripheral edge of the air seal 313 on the air supply side is pushed against the inner wall surface of the air cylinder 311 on the air supply side.

[0177] The air supply side air seal 313 reciprocates together with the air supply side piston 312 while being pressed against the inner wall surface of the air supply side cylinder 311. Therefore, the outer peripheral edge portion of the air supply side air seal 313 gradually wears.

[0178] <Exhaust side air seal>

[0179] like Fig.10 As shown, in the exhaust pump 320 , the outer peripheral edge portion of the exhaust-side air seal 323 slides on the inner wall surface of the exhaust-side cylinder 321 .

[0180] During operation of the exhaust pump 320, the pressure in the back pressure chamber 328 is higher than the pressure in the gas chamber 327. Therefore, the outer peripheral edge of the exhaust side air seal 323 is pushed open by the gas pressure in the back pressure chamber 328 and pressed against the inner wall surface of the exhaust side cylinder 321.

[0181] Furthermore, during the operation of the exhaust pump 320, the temperature of the exhaust-side cylinder 321 reaches about 65° C., and the temperature of the exhaust-side air seal 323 also approaches 65° C. Therefore, during the operation of the exhaust pump 320, the exhaust-side air seal 323 thermally expands, and the outer peripheral edge of the exhaust-side air seal 323 is pressed against the inner wall surface of the exhaust-side cylinder 321.

[0182] The exhaust-side air seal 323 reciprocates together with the exhaust-side piston 322 while being pressed against the inner wall surface of the exhaust-side cylinder 321. Therefore, the outer peripheral edge portion of the exhaust-side air seal 323 gradually wears.

[0183] - Selection of exhaust side air seal -

[0184] like Fig.11 As shown, in the air seal member mainly composed of fluororesin 350 and fibrous carbon material 351, fibrous carbon material 351 is dispersed in fluororesin 350. If the air seal member is worn, fibrous carbon material 351 comes into contact with the wall surface of the cylinder and is scraped off by the cylinder.

[0185] The fibrous carbon material 351 has an elongated shape. Therefore, even if a portion of the fibrous carbon material 351 is exposed on the surface of the air seal and is in contact with the cylinder, the remaining portion of the fibrous carbon material 351 continues to be held by the fluororesin 350. As a result, the air seal including the fibrous carbon material 351 can continue to exhibit the wear reduction effect of the fibrous carbon material 351.

[0186] On the other hand, if the air seal mainly composed of fluororesin and granular carbon material wears and the granular carbon material contacts the cylinder, the granular carbon material falls off from the air seal. If the granular carbon material falls off from the air seal, the wear reduction effect brought by the granular carbon material is impaired, and the air seal is more likely to wear further.

[0187] Therefore, if the air seal used as the exhaust side air seal 323 is changed from "air seal with fluororesin and granular carbon material as main components" to "air seal with fluororesin and fibrous carbon material as main components", the life of the exhaust side air seal 323 is extended due to the wear reducing effect of the fibrous carbon material.

[0188] - Selection of air seals on the air supply side -

[0189] Taking into account the above-mentioned "wear reducing effect of fibrous carbon material", if the air seal used as the air supply side air seal 313 is changed from "air seal with fluororesin and granular carbon material as main components" to "air seal with fluororesin and fibrous carbon material as main components", it can be expected that the life of the air supply side air seal 313 will be extended.

[0190] However, if the "air seal having fluororesin and fibrous carbon material as main components" is used as the air supply side air seal 313, the life of the air supply side air seal 313 will be shortened compared to the case where the "air seal having fluororesin and granular carbon material as main components" is used as the air supply side air seal 313. Therefore, in the air pump of the present embodiment, the "air seal having fluororesin and granular carbon material as main components" is used as the air supply side air seal 313. Here, the reason is explained.

[0191] <Deformation of air seals due to gas pressure>

[0192] Fig.12 The figure shows the time-dependent changes of the suction side pressure and the discharge side pressure of each of the air supply pump 310 and the exhaust pump 320. The suction side pressure is the pressure of the gas sucked into the gas chambers 317 and 327 through the suction ports 315a and 325a. The discharge side pressure is the pressure of the gas discharged from the gas chambers 317 and 327 through the discharge ports 315b and 325b. The suction side pressure and the discharge side pressure change periodically in conjunction with the switching between the first action and the second action of the gas composition adjusting device 100.

[0193] The average gas pressure acting on the air seal 313 on the air supply side during the operation of the air pump 300 can be calculated by Fig.12 The integrated value of the discharge side pressure of the air supply pump 310 is Fig.12 On the other hand, the average gas pressure acting on the exhaust side air seal 323 during the operation of the air pump 300 can be calculated by Fig.12 The integrated value of the suction side pressure of the exhaust pump 320 is Fig.12 In the air pump 300 of the present embodiment, the area of ​​the area Ad related to the air supply pump 310 is about 1.5 times the area of ​​the area As related to the exhaust pump 320 .

[0194] Thus, in the air pump 300 of the present embodiment, the average gas pressure acting on the air seal 313 on the air supply side is greater than the average gas pressure acting on the air seal 323 on the exhaust side. Therefore, when the Young's modulus of the air seal 313 on the air supply side is the same as the Young's modulus of the air seal 323 on the exhaust side, the amount of deformation of the air seal 313 on the air supply side caused by the gas pressure is greater. As a result, the force that pushes the air seal 313 on the air supply side cylinder 311 is greater, and the amount of wear of the air seal 313 on the air supply side increases. Therefore, the Young's modulus of the air seal 313 on the air supply side is preferably greater than the Young's modulus of the air seal 323 on the exhaust side.

[0195] <Thermal expansion of air seals>

[0196] As described above, during the operation of the air pump 300, the temperature of the air seal 313 on the air supply side is higher than the temperature of the air seal 323 on the air exhaust side. Therefore, in the case where the linear expansion coefficient of the air seal 313 on the air supply side is the same as the linear expansion coefficient of the air seal 323 on the air exhaust side, the thermal expansion amount of the air seal 313 on the air supply side is larger. As a result, the force that pushes the air seal 313 on the air supply side cylinder 311 increases, and the wear amount of the air seal 313 on the air supply side increases. Therefore, the linear expansion coefficient of the air seal 313 on the air supply side is preferably smaller than the linear expansion coefficient of the air seal 323 on the air exhaust side.

[0197] <Wear reduction effect of carbon materials>

[0198] As described above, the fibrous carbon material has a greater effect of reducing the wear of the air seal than the granular carbon material. However, with respect to the air seal 313 on the air supply side of the air pump of this embodiment, the increase in the amount of wear of the air seal caused by "the average gas pressure acting on the air seal" and "the high temperature of the air seal" exceeds the wear reduction effect of the fibrous carbon material.

[0199] Therefore, in the air pump 300 of this embodiment, as the air supply side air seal 313, "an air seal having fluororesin and granular carbon material as main components, having a Young's modulus larger than that of the exhaust side air seal 323 and a linear expansion coefficient smaller than that of the exhaust side air seal 323" is used.

[0200] - Features of the first embodiment -

[0201] In the exhaust pump 320 of the present embodiment, when the exhaust side air seal 323 slides on the exhaust side cylinder 321, the fibrous carbon material is exposed on the surface of the exhaust side air seal 323 and contacts the exhaust side cylinder 321. Since the fibrous carbon material has an elongated shape, it is difficult for the exhaust side air seal 323 to fall off even if it contacts the exhaust side cylinder 321. The exhaust side air seal 323, which is mainly composed of the fibrous carbon material, is difficult to wear because the wear reduction effect brought by the fibrous carbon material lasts for a long time. Therefore, in the present embodiment, the life of the exhaust side air seal 323 of the exhaust pump 320 is extended, and the reliability of the gas composition adjustment device 100 is improved.

[0202] In the air pump 300 of the present embodiment, the linear expansion coefficient of the air supply side air seal 313 is smaller than the linear expansion coefficient of the exhaust side air seal 323. Therefore, compared with the case where the linear expansion coefficient of the air supply side air seal 313 and the linear expansion coefficient of the exhaust side air seal 323 are equal, in the air supply pump 310 whose temperature is higher than that of the exhaust pump 320, the amount of thermal expansion of the air supply side air seal 313 becomes smaller. As a result, in the air supply pump 310 of this aspect, the force that pushes the air supply side air seal 313 onto the air supply side cylinder 311 becomes smaller, and the life of the air supply side air seal 313 is extended.

[0203] In the air pump 300 of the present embodiment, the Young's modulus of the air seal 313 on the air supply side is larger than the Young's modulus of the air seal 323 on the air exhaust side. Therefore, compared with the case where the Young's modulus of the air seal 313 on the air supply side and the Young's modulus of the air seal 323 on the air exhaust side are equal, the amount of deformation of the air seal 313 on the air supply side caused by the gas pressure in the air pump 310 becomes smaller. As a result, in the air pump 310 of this aspect, the force that pushes the air seal 313 on the air supply side cylinder 311 becomes smaller, and the life of the air seal 313 on the air supply side is extended.

[0204] Thus, in the gas composition adjusting device 100 of the present embodiment, by using "an air seal having a fluororesin and a granular carbon material as main components, a linear expansion coefficient lower than that of the exhaust side air seal 323, and a Young's modulus higher than that of the exhaust side air seal 323" as the supply side air seal 313, the life of the supply side air seal 313 is extended. In other words, by using "an air seal having a linear expansion coefficient and a Young's modulus suitable for use in the air supply pump 310, although the wear reduction effect of the carbon material is poor" as the supply side air seal 313, the life of the supply side air seal 313 is extended.

[0205] Therefore, in the gas composition adjusting device 100 of the present embodiment, the life of both the supply-side air seal 313 and the exhaust-side air seal 323 can be extended, and the reliability of the air pump 300 and the gas composition adjusting device 100 can be improved.

[0206] - Modification 1 of the First Embodiment -

[0207] In the gas composition adjusting device 100 of the present embodiment, the controller 110 may have a function of estimating the amount of wear of the air seals 313 , 323 .

[0208] The wear amount Vw of the air seals 313 and 323 is calculated using the following mathematical formula 1.

[0209] (Mathematical formula 1) Vw = C1×F×L+C2×N

[0210] “C1” is a constant related to the amount of wear of the air seals 313 and 323 during operation of the air pump 300. The constant “C1” is predetermined by performing a test run of the air pump 300 when designing the air pump 300. The constant “C1” is recorded in the storage device 112 of the controller 110.

[0211] "F" is a force that pushes the air seals 313, 323 onto the cylinders 311, 321 during operation of the air pump 300. "F" is determined based on the gas pressure of the gas chambers 317, 327. The gas pressure of the gas chambers 317, 327 during operation of the air pump 300 is predetermined when designing the gas composition regulating device 100. The force "F" is recorded in the storage device 112 of the controller 110.

[0212] "L" is the distance that the air seals 313, 323 move as the pistons 312, 322 reciprocate. The distance that the pistons 312, 322 move when they reciprocate once is determined when the air pump 300 is designed. In addition, the number of times the pistons 312, 322 reciprocate per unit time is also determined when the air pump 300 is designed. Therefore, the distance "L" is proportional to the operating time of the air pump 300. Therefore, the controller 110 calculates the distance "L" based on the operating time of the air pump 300.

[0213] “C2” is a constant related to the amount of wear of the air seals 313, 323 caused by the start of the air pump 300. The constant “C2” is predetermined by performing a test run of the air pump 300 when designing the air pump 300. The constant “C2” is recorded in the storage device 112 of the controller 110.

[0214] "N" is the number of times the air pump 300 is started from a stopped state. The controller 110 counts the number of times the air pump 300 is started from a stopped state.

[0215] The controller 110 records the operating time and the number of starts of the air pump 300. Then, the controller 110 calculates the wear amount Vw of the air seals 313 and 323 using the operating time and the number of starts of the air pump 300 and the mathematical formula 1. When the calculated wear amount Vw of the air seals 313 and 323 reaches a predetermined reference value, the controller 110 displays a message for urging the administrator of the gas composition adjusting device 100 to replace the air seals 313 and 323 on the display panel of the transport refrigeration device 10, for example.

[0216] - Modification 2 of the first embodiment -

[0217] The gas composition regulating device 100 of this embodiment can also be set in a stationary refrigerator or freezer. The gas composition regulating device 100 of this embodiment can also be set in a land-based refrigerated / frozen container transported by truck or railway. The gas composition regulating device 100 of this embodiment can also be set in a refrigerated / frozen truck in which the box body forming the cargo hold and the chassis are integrated.

[0218] (Second Embodiment)

[0219] The gas composition regulating device 100 of the present embodiment constitutes an oxygen concentrator. The gas composition regulating device 100 of the present embodiment supplies oxygen-rich gas to a user such as a patient with a respiratory disease. Here, the differences between the gas composition regulating device 100 of the present embodiment and the gas composition regulating device 100 of the first embodiment are described.

[0220] like Fig.13 As shown, in the gas composition regulating device 100 of the present embodiment, as in the first embodiment, the first outflow pipe 244 and the second outflow pipe 245 respectively extend to the outside of the unit housing 201. The gas composition regulating device 100 of the present embodiment discharges nitrogen-rich gas through the first outflow pipe 244, and supplies oxygen-rich gas to the user through the second outflow pipe 245.

[0221] In the gas composition regulating device 100 of the present embodiment, an oxygen tank 401 and a flow regulating valve 402 are provided on the second outflow pipe 245. The oxygen tank 401 is arranged on the upstream side of the orifice plate 263. The flow regulating valve 402 is a regulating valve with a variable opening. The flow regulating valve 402 is arranged on the downstream side of the orifice plate 263. In addition, in the gas composition regulating device 100 of the present embodiment, the ventilation exhaust pipe 150, the sensor unit 160, the bypass connecting pipe 255, the exhaust connecting pipe 271, and the measuring pipe 281 are omitted.

[0222] - Operation of the gas composition adjustment device -

[0223] The gas composition adjusting device 100 of this embodiment repeats the first operation and the second operation alternately as in the gas composition adjusting device 100 of the first embodiment. The gas composition adjusting device 100 of this embodiment operates continuously without stopping in principle.

[0224] In the first operation, the oxygen-rich gas flowing out of the first adsorption cylinder 234 is supplied to the user through the second outflow pipe 245. In the first operation, the nitrogen-rich gas sucked out of the second adsorption cylinder 235 by the exhaust pump 320 is discharged to the outside through the first outflow pipe 244.

[0225] In the second operation, the oxygen-rich gas flowing out of the second adsorption cylinder 235 is supplied to the user through the second outflow pipe 245. In the second operation, the nitrogen-rich gas sucked out of the first adsorption cylinder 234 by the exhaust pump 320 is discharged to the outside through the first outflow pipe 244.

[0226] The above describes the implementation methods and variations, but it should be understood that various changes can be made to the methods and specific circumstances without departing from the subject matter and scope of the claims. The above implementation methods and variations can also be appropriately combined and replaced as long as they do not affect the functions of the objects disclosed. The words "first", "second", etc. in the specification and claims are only used to distinguish sentences containing the above words, and are not intended to limit the number or order of the sentences.

[0227] - Industrial Applicability -

[0228] In summary, the present disclosure is useful for a gas composition regulating device.

[0229] - Explanation of symbols -

[0230] 100 Gas composition regulating device

[0231] 234 The first adsorption cylinder (adsorber)

[0232] 235 Second adsorption cylinder (adsorber)

[0233] 310 air supply pump

[0234] 311 air supply side cylinder (cylinder)

[0235] 312 air supply side piston (piston)

[0236] 313 Air seal on the air supply side (sealing component)

[0237] 320 Exhaust Pump

[0238] 321 Exhaust side cylinder (cylinder)

[0239] 322 Exhaust side piston (piston)

[0240] 323 Exhaust side air seal (sealing component)

Claims

1. A gas composition regulating device (100), comprising an adsorber, an air supply pump (310) and an exhaust pump (320), wherein the adsorber has an adsorbent for adsorbing at least one component in a treated gas, the air supply pump (310) supplies the treated gas to the adsorber, and the exhaust pump (320) sucks gas out of the adsorber, and the gas composition regulating device (100) performs a pressurizing action and a decompressing action, wherein in the pressurizing action, the treated gas pressurized by the air supply pump (310) is supplied to the adsorber, and the gas flowing out of the adsorber is sent out as a first gas, and in the decompressing action, the exhaust pump (320) sucks gas out of the adsorber and ejects it, and the gas ejected by the exhaust pump (320) is sent out as a second gas, characterized in that: The air supply pump (310) is a positive displacement pump comprising an air supply side cylinder (311), an air supply side piston (312), and an air supply side sealing component (313). The air supply side piston (312) is accommodated in the air supply side cylinder (311), and the air supply side sealing component (313) is installed on the air supply side piston (312) and seals the gap between the air supply side cylinder (311) and the air supply side piston (312). The exhaust pump (320) is a positive displacement pump including an exhaust side cylinder (321), an exhaust side piston (322), and an exhaust side sealing component (323). The exhaust side piston (322) is accommodated in the exhaust side cylinder (321). The exhaust side sealing component (323) is mounted on the exhaust side piston (322) and seals the gap between the exhaust side cylinder (321) and the exhaust side piston (322). The exhaust side sealing member (323) is mainly composed of fluororesin and fibrous carbon material. The main components of the air supply side sealing member (313) are fluororesin and granular carbon material.

2. The gas composition regulating device (100) according to claim 1, characterized in that: The linear expansion coefficient of the air supply side sealing component (313) is smaller than the linear expansion coefficient of the exhaust side sealing component (323).

3. The gas composition regulating device (100) according to claim 1 or 2, characterized in that: The Young's modulus of the air supply side sealing member (313) is greater than the Young's modulus of the air exhaust side sealing member (323).

4. The gas composition regulating device (100) according to claim 1 or 2, characterized in that: The processed gas is atmosphere, The adsorbent of the adsorber adsorbs nitrogen as a component of the gas to be processed. The first gas has a lower nitrogen concentration and a higher oxygen concentration than the processed gas, The second gas has a higher nitrogen concentration and a lower oxygen concentration than the processed gas, The gas composition adjusting device (100) operates to supply the second gas to a storage room (2) storing fresh food.

5. The gas composition regulating device (100) according to claim 1 or 2, characterized in that: The processed gas is atmosphere, The adsorbent of the adsorber adsorbs nitrogen as a component of the gas to be processed. The first gas has a lower nitrogen concentration and a higher oxygen concentration than the processed gas, The second gas has a higher nitrogen concentration and a lower oxygen concentration than the processed gas, The gas composition adjusting device (100) operates to supply the first gas to a user.

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