WO2022044511A1

WO2022044511A1 - Air composition adjusting device, refrigeration device, container, and air composition adjusting method

Info

Publication number: WO2022044511A1
Application number: PCT/JP2021/023566
Authority: WO
Inventors: 完池宮; 紀考亀井
Original assignee: ダイキン工業株式会社
Priority date: 2020-08-31
Filing date: 2021-06-22
Publication date: 2022-03-03
Also published as: JP7064154B2; JP2022040482A

Abstract

According to the present invention, air of which the composition has been an adjusted is delivered to a target space. The concentration of components in the air in the target space are measured by a sensor (51). The sensor (51) is accommodated in a sensor casing (90). A control unit (55) executes a first action. The first action introduces external air into the inside of the sensor casing (90) in conjunction with an operation stopping action of an air composition adjusting device (60).

Description

Air composition adjusting device, refrigerating device, container, and air composition adjusting method

The present disclosure relates to an air composition adjusting device, a refrigerating device, a container, and an air composition adjusting method.

Patent Document 1 discloses a refrigerated container provided with an air composition adjusting device. The air composition adjusting device adjusts the oxygen concentration and the carbon dioxide concentration in the space inside the container. The air composition adjusting device of Patent Document 1 has a sensor for measuring the composition of air.

Japanese Unexamined Patent Publication No. 08-000168

By the way, in the space inside the container, corrosive components may be generated from objects to be cooled such as cargo. In the configuration in which the sensor is housed in the sensor casing, the corrosive component flows into the sensor casing together with the air in the refrigerator.

Here, if the air does not flow in the sensor casing due to the stop of the operation of the air composition adjusting device, the corrosive component stays in the sensor casing, and the sensor may be deteriorated due to the corrosive component. ..

The purpose of this disclosure is to suppress deterioration of the sensor due to corrosive components.

The first aspect of the present disclosure is an air composition adjusting device for introducing air adjusted to a composition different from that of the outside air into the target space, the adjusting unit (34,35) for adjusting the composition of the air, and the target space. A transport unit (31) that conveys air to the air, a sensor (51) that measures the concentration of components in the air in the target space, a sensor casing (90) that houses the sensor (51), and the air composition adjustment. A control unit (55) for executing a first operation of introducing outside air into the inside of the sensor casing (90) is provided in conjunction with the operation stop operation of the device (60).

In the first aspect, the air whose composition has been adjusted is conveyed to the target space. The concentration of components in the air in the target space is measured by the sensor (51). The sensor (51) is housed in the sensor casing (90). The control unit (55) executes the first operation. The first operation is an operation of introducing outside air into the inside of the sensor casing (90) in conjunction with the operation stop operation of the air composition adjusting device (60).

When outside air is introduced inside the sensor casing (90), the corrosive component staying inside the sensor casing (90) is discharged to the outside of the sensor casing (90). As a result, it is possible to prevent the sensor (51) from being deteriorated by the corrosive component while the operation of the air composition adjusting device (60) is stopped.

A second aspect of the present disclosure comprises, in the first aspect, a passage (75,76) for introducing outside air into the sensor casing (90), wherein the control unit (55) is in the first operation. , The transport unit (31) is controlled so as to introduce outside air into the inside of the sensor casing (90) through the passage (75,76).

In the second aspect, in the first operation, the outside air can be introduced into the inside of the sensor casing (90) through the passage (75,76) by controlling the transport unit (31).

The third aspect of the present disclosure is a refrigerating device provided with the air composition adjusting device (60) according to the first or second aspect.

In the third aspect, in the refrigerating apparatus provided with the air composition adjusting device (60), the deterioration of the sensor (51) due to the corrosive component can be suppressed by discharging the corrosive component to the outside of the sensor casing (90). ..

A fourth aspect of the present disclosure includes, in the third aspect, a ventilation port (16D) that communicates the inside and the outside of the target space, and an opening / closing mechanism (16C) that opens and closes the ventilation port (16D). During the first operation, the opening / closing mechanism (16C) is in an open state.

In the fourth aspect, the inside and the outside of the target space are communicated by a ventilation port (16D). The ventilation port (16D) is opened and closed by the opening / closing mechanism (16C). The opening / closing mechanism (16C) is in the open state during the first operation.

As a result, by opening the opening / closing mechanism (16C) during the first operation, outside air can be introduced into the target space through the ventilation port (16D).

A fifth aspect of the present disclosure is, in the third or fourth aspect, the control unit (55) is linked to the operation stop operation of the refrigerating apparatus (10), and the outside air is inside the sensor casing (90). The second operation of introducing is executed.

In the fifth aspect, the control unit (55) executes the second operation. The second operation is an operation of introducing outside air into the inside of the sensor casing (90) in conjunction with the operation of stopping the operation of the refrigerating device (10).

When outside air is introduced inside the sensor casing (90), the corrosive component staying inside the sensor casing (90) is discharged to the outside of the sensor casing (90). As a result, it is possible to prevent the sensor (51) from being deteriorated by the corrosive component while the refrigerating device (10) is stopped.

The sixth aspect of the present disclosure is a container provided with the refrigerating apparatus (10) according to any one of the third to fifth aspects.

In the sixth aspect, in the container provided with the refrigerating device (10), the deterioration of the sensor (51) due to the corrosive component can be suppressed by discharging the corrosive component to the outside of the sensor casing (90).

A seventh aspect of the present disclosure is an air composition adjusting device (60) using an air composition adjusting device (60) that introduces air adjusted to a composition different from that of the outside air into the target space, wherein the air composition adjusting device (60) is used. Then, a sensor (51) for measuring the concentration of components in the air in the target space is housed in the sensor casing (90), and a step of adjusting the composition of the air and a step of transporting the air to the target space. And a step of introducing outside air into the inside of the sensor casing (90) in conjunction with the operation stop operation of the air composition adjusting device (60).

In the seventh aspect, the sensor (51) is housed in the sensor casing (90). The air composition adjusting device (60) adjusts the composition of the air and conveys the air to the target space. The outside air is introduced into the sensor casing (90) in conjunction with the stop operation of the air composition adjusting device (60).

FIG. 1 is a perspective view of the transport refrigerating apparatus according to the first embodiment as viewed from the outside of the refrigerator. FIG. 2 is a side sectional view showing a schematic configuration of a refrigerating apparatus for transportation. FIG. 3 is a piping system diagram showing the configuration of the refrigerant circuit of the transport refrigerating device. FIG. 4 is a piping system diagram showing an air circuit of an air composition adjusting device, and shows an air flow in the first generation operation. FIG. 5 is a piping system diagram showing the air circuit of the air composition adjusting device, and shows the air flow in the second generation operation. FIG. 6 is a piping system diagram showing an air circuit of an air composition adjusting device, and shows an air flow in an outside air introduction operation. FIG. 7 is a piping system diagram showing an air circuit of an air composition adjusting device, and shows an air flow in a sensor calibration operation. FIG. 8 is a rear perspective view of the casing of the refrigerating apparatus for transportation, showing the arrangement of the sensor unit. FIG. 9 is a flowchart showing the procedure of the first operation. FIG. 10 is a flowchart showing the procedure of the second operation. FIG. 11 is a perspective view of the transport refrigerating apparatus according to the second embodiment. FIG. 12 is a piping system diagram showing an air circuit of the air composition adjusting device.

<< Embodiment 1 >>
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings.

<overall structure>
As shown in FIGS. 1 and 2, the present embodiment relates to a transport container (1) provided with an air composition adjusting device (60). The air composition adjusting device (60) introduces air adjusted to a composition different from that of the outside air into the target space. The air composition adjusting device (60) includes a gas supply unit (30) and a sensor unit (50).

The gas supply unit (30) has an adjusting unit for adjusting the composition of air, a transport unit for transporting air, and an air circuit (3). The adjusting unit includes a first suction cylinder (34) and a second suction cylinder (35), which will be described later (see FIG. 4). The transport unit includes an air pump (31) described later (see FIG. 4). The air circuit (3) introduces air into the first suction cylinder (34) and the second suction cylinder (35) by the air pump (31), and supplies the air having the adjusted composition to the target space.

The sensor unit (50) has a sensor that measures the concentration of components in the air in the target space. Sensors include an oxygen sensor (51) and a carbon dioxide sensor (52).

<Transport container>
The transportation container (1) includes a container body (2) and a transportation refrigerating device (10). The transportation container (1) is used for marine transportation and the like. The transport refrigerating device (10) cools the air in the internal space (target space) of the container body (2).

Plants (15) as perishables are stored in a box in the interior space of the container body (2). The plant (15) is, for example, fruits and vegetables such as bananas and avocados, vegetables, grains, bulbs, fresh flowers and the like. The plant (15) breathes by taking in oxygen (O2) in the air and releasing carbon dioxide (CO2).

The container body (2) is formed in the shape of an elongated rectangular parallelepiped box with one end face open. The transport refrigerating device (10) includes a refrigerating casing (12), a refrigerant circuit (20), and an air composition adjusting device (60) (Controlled Atmosphere System). The freezing casing (12) is attached so as to close the open end of the container body (2).

<Transport refrigeration equipment>
The transport refrigeration system (10) includes a refrigerant circuit (20) that performs a refrigeration cycle. The transport refrigerating device (10) cools the air inside the container body (2) by the evaporator (24) of the refrigerant circuit (20).

<casing>
The freezing casing (12) has an outer wall (12a) and an inner wall (12b). The outer wall (12a) is located on the outside of the container body (2). The inner wall (12b) is located inside the container body (2). The outer wall (12a) and the inner wall (12b) of the refrigerator are made of, for example, an aluminum alloy.

The outer wall (12a) is attached to the peripheral edge of the opening of the container body (2) so as to close the opening end of the container body (2). The lower part of the outer wall (12a) bulges toward the inside of the container body (2).

The inner wall (12b) is placed facing the outer wall (12a). The inner wall (12b) bulges inward corresponding to the lower part of the outer wall (12a). A heat insulating material (12c) is provided in the space between the inner wall (12b) and the outer wall (12a).

In this way, the lower part of the freezing casing (12) bulges toward the inside of the container body (2). As a result, an outside storage space (S1) is formed on the outside of the container body (2) at the bottom of the freezing casing (12). Further, an internal storage space (S2) is formed inside the container body (2) at the upper part of the freezing casing (12).

As shown in FIG. 1, the refrigerating casing (12) is formed with two service openings (14) for maintenance arranged side by side in the width direction. The two service openings (14) are closed by a first service door (16A) and a second service door (16B) that can be opened and closed, respectively.

A ventilation port (16D) is formed on the second service door (16B). The ventilation port (16D) communicates with the space inside and outside the container body (2). The ventilation port (16D) is opened and closed by a rotating lid (16C) as an opening / closing mechanism. The rotary lid (16C) can rotate around the central axis. The rotary lid (16C) is manually rotated by the user to switch between an open state in which the ventilation port (16D) is opened and a closed state in which the ventilation port (16D) is closed.

Specifically, an opening is formed in the rotary lid (16C). By communicating the opening of the rotary lid (16C) with the ventilation port (16D) of the second service door (16B), the ventilation port (16D) is opened. In the present embodiment, the second service door (16B) is formed with two ventilation ports, a first ventilation port and a second ventilation port, at positions symmetrical with respect to the central axis. The rotary lid (16C) is formed with two openings corresponding to the first ventilation port and the second ventilation port.

The first ventilation port communicates with the primary space (S21) on the suction side of the internal fan (26) and the external space in the open state. The second ventilation port communicates with the secondary space (S22) on the outlet side of the internal fan (26) and the external space in the open state. By rotationally driving the internal fan (26), outside air is supplied from the external space to the primary space (S21) through the first ventilation port. By rotationally driving the internal fan (26), the internal air is exhausted from the secondary space (S22) to the external space through the second ventilation port.

A motor (not shown) for rotating the rotary lid (16C) may be provided. In this case, the unit control unit (100) may control the opening / closing operation of the rotary lid (16C).

As shown in FIG. 2, a partition plate (18) is arranged in the container body (2). The partition plate (18) is composed of a substantially rectangular plate member. The partition plate (18) is arranged to face the inner surface of the freezing casing (12). The partition plate (18) divides the interior space (target space) in which the plants (15) in the refrigerator of the container body (2) are stored and the interior storage space (S2).

A suction port (18a) is formed between the upper end of the partition plate (18) and the ceiling surface in the container body (2). The air inside the container body (2) is taken into the storage space (S2) inside the refrigerator through the suction port (18a).

The storage space (S2) in the refrigerator will be provided with a partition wall (13) extending in the horizontal direction. The partition wall (13) is attached to the upper end of the partition plate (18). The partition wall (13) has an opening in which the internal fan (26) is installed. The partition wall (13) has a storage space (S2) in the refrigerator, a primary space (S21) on the suction side of the fan (26) in the refrigerator, and a secondary space (S22) on the outlet side of the fan (26) in the refrigerator. And partition. In the present embodiment, the primary space (S21) is provided on the upper side of the partition wall (13), and the secondary space (S22) is provided on the lower side of the partition wall (13).

Inside the container body (2), a floor plate (19) is provided above the bottom surface of the container body (2). Boxed plants (15) are placed on the floorboard (19). An underfloor flow path (19a) is formed between the bottom surface of the container body (2) and the floor plate (19). A gap is provided between the lower end of the partition plate (18) and the bottom surface in the container body (2), and the storage space (S2) in the refrigerator communicates with the underfloor flow path (19a).

An outlet (18b) is formed on the back side (right side in FIG. 2) of the container body (2) on the floor plate (19). The air outlet (18b) blows the air cooled by the transport refrigerating device (10) into the container body (2).

<Refrigerant circuit configuration and equipment layout>
As shown in FIG. 3, in the refrigerant circuit (20), the compressor (21), the condenser (22), the expansion valve (23), and the evaporator (24) are sequentially connected by the refrigerant pipe (20a). It is a closed circuit configured by connecting. The unit control unit (100) controls the operation of the compressor (21), the expansion valve (23), the outside fan (25), and the inside fan (26).

An outside fan (25) is installed near the condenser (22). The outside fan (25) is rotationally driven by the outside fan motor (25a). The outside fan (25) sends the air (outside air) in the outside space of the container body (2) to the condenser (22). In the condenser (22), heat is generated between the refrigerant compressed by the compressor (21) and flowing inside the condenser (22) and the outside air sent to the condenser (22) by the outside fan (25). The exchange will take place.

Two internal fans (26) are installed near the evaporator (24). The internal fan (26) is rotationally driven by the internal fan motor (26a). The internal fan (26) sucks in the internal air of the container body (2) from the suction port (18a) and blows it out to the evaporator (24). In the evaporator (24), between the refrigerant decompressed by the expansion valve (23) and flowing inside the evaporator (24) and the internal air sent to the evaporator (24) by the internal fan (26). Heat exchange takes place at.

As shown in FIG. 1, the compressor (21) and the condenser (22) are stored in the storage space (S1) outside the refrigerator. The condenser (22) is arranged in the central part in the vertical direction of the storage space (S1) outside the refrigerator. The condenser (22) divides the storage space (S1) outside the refrigerator into a first space (S11) on the lower side and a second space (S12) on the upper side.

The first space (S11) is provided with a compressor (21), an inverter box (29), and a gas supply unit (30) of the air composition adjusting device (60). The inverter box (29) houses a drive circuit that drives the compressor (21) at a variable speed. In the second space (S12), an outside fan (25) and an electrical component box (17) are provided.

As shown in FIG. 2, the evaporator (24) is stored in the secondary space (S22) of the storage space (S2) in the refrigerator. Above the evaporator (24) of the internal storage space (S2), the above-mentioned two internal fans (26) are arranged side by side in the width direction of the refrigerating casing (12) (see FIG. 1).

<Air composition adjuster>
As shown in FIGS. 4 to 7, the air composition adjusting device (60) includes a gas supply unit (30), an exhaust unit (46), a sensor unit (50), and a control unit (55). The air composition adjusting device (60) adjusts the oxygen concentration and the carbon dioxide concentration of the air inside the container body (2). In addition, all "concentrations" used in the following description refer to "volume concentration".

<Gas supply unit>
The gas supply unit (30) is a unit for producing air whose composition has been adjusted. In the present embodiment, the gas supply unit (30) generates nitrogen-concentrated air having a low oxygen concentration for supplying into the refrigerator of the container body (2). The gas supply unit (30) is configured by VPSA (Vacuum Pressure Swing Adsorption). As shown in FIG. 1, the gas supply unit (30) is arranged in the lower left corner portion of the storage space (S1) outside the refrigerator.

As shown in FIG. 4, the gas supply unit (30) has an air pump (31), a first-direction control valve (32), a second-direction control valve (33), and an air circuit (3). The first suction cylinder (34) and the second suction cylinder (35) are connected to the air circuit (3). Inside the first adsorption cylinder (34) and the second adsorption cylinder (35), an adsorbent for adsorbing a nitrogen component in the air is provided. The components of the air circuit (3) are housed in the unit case (36).

(air pump)
The air pump (31) has a first pump mechanism (31a) and a second pump mechanism (31b). The first pump mechanism (31a) constitutes a pressure pump mechanism that pressurizes and discharges the sucked air. The second pump mechanism (31b) constitutes a decompression pump mechanism. The first pump mechanism (31a) and the second pump mechanism (31b) are connected to the drive shaft of the motor (31c).

(Air circuit)
Components such as an air pump (31) are connected to the air circuit (3). The air circuit (3) includes an outside air passage (41), a pressurized passage (42), a decompression passage (43), and a supply passage (44).

The outside air passage (41) penetrates the unit case (36) inside and outside. One end of the outside air passage (41) is connected to the suction port of the first pump mechanism (31a). A membrane filter (37) is provided at the other end of the outside air passage (41). The membrane filter (37) is a filter having both breathability and waterproofness. Although not shown, the other end of the outside air passage (41) provided with the membrane filter (37) is arranged in the second space (S12) above the condenser (22) of the outside storage space (S1). ..

One end of the pressurizing passage (42) is connected to the discharge port of the first pump mechanism (31a). The other end of the pressurizing passage (42) branches into two and is connected to the first direction control valve (32) and the second direction control valve (33).

One end of the decompression passage (43) is connected to the suction port of the second pump mechanism (31b). The other end of the pressure reducing passage (43) branches into two and is connected to the first direction control valve (32) and the second direction control valve (33). One end of the supply passage (44) is connected to the discharge port of the second pump mechanism (31b). The other end of the supply passage (44) opens to the secondary space (S22) on the outlet side of the internal fan (26) in the internal storage space (S2) of the container body (2). A check valve (65) is provided at the other end of the supply passage (44). The check valve (65) allows the flow of air toward the storage space (S2) in the refrigerator and prevents the backflow of air.

Two blower fans (49) are installed on the side of the air pump (31). The blower fan (49) cools the air pump (31) by blowing air toward the air pump (31).

The first pump mechanism (31a), which is a pressure pump mechanism, supplies pressurized air to one of the first suction cylinders (34) and the second suction cylinder (35). An adsorption operation is performed in which the nitrogen component in the pressurized air is adsorbed on the adsorbent in the adsorption cylinder.

The second pump mechanism (31b), which is a decompression pump mechanism, sucks air from the other suction cylinder of the first suction cylinder (34) and the second suction cylinder (35), thereby sucking air into the adsorption cylinder. Performs a desorption operation to desorb the nitrogen component adsorbed on the water. The desorption operation produces nitrogen-enriched air.

In the first suction cylinder (34) and the second suction cylinder (35), the suction operation and the desorption operation are alternately performed. The supply passage (44) is a passage for supplying the nitrogen-enriched air generated by the desorption operation into the refrigerator of the container body (2).

The outlet portion of the first pump mechanism (31a) of the pressurizing passage (42) and the outlet portion of the second pump mechanism (31b) of the supply passage (44) are connected by a bypass passage (47). The outlet portion of the first pump mechanism (31a) is between the first pump mechanism (31a) and the first direction control valve (32) and the second direction control valve (33). A bypass on-off valve (48) is provided in the bypass passage (47). The bypass on-off valve (48) is controlled to open and close by the control unit (55).

The outside air introduction passage (40) is composed of an outside air passage (41), a part of the pressure passage (42), a bypass passage (47), and a part of the supply passage (44). The outside air introduction passage (40) supplies pressurized air that has passed through the first pump mechanism (31a) into the refrigerator. The composition of the pressurized air is equal to the composition of the outside air. A cooling unit (40a) is provided in the outside air introduction passage (40). The cooling unit (40a) passes through the space outside the unit case (36).

(Direction control valve)
The first direction control valve (32) and the second direction control valve (33) are provided in the air circuit (3). The first direction control valve (32) and the second direction control valve (33) are arranged between the air pump (31) and the first suction cylinder (34) and the second suction cylinder (35). The first-direction control valve (32) and the second-direction control valve (33) have two connections, which will be described later, in which the air pump (31) is connected to the first suction cylinder (34) and the second suction cylinder (35). Switch to the state (first or second connection state). The switching operation of the first direction control valve (32) and the second direction control valve (33) is controlled by the control unit (55).

The first direction control valve (32) is connected to the pressurizing passage (42), the depressurizing passage (43), and one end of the first suction cylinder (34). The pressurizing passage (42) is connected to the discharge port of the first pump mechanism (31a). The decompression passage (43) is connected to the suction port of the second pump mechanism (31b). One end of the first suction cylinder (34) is an inflow port at the time of pressurization.

The first direction control valve (32) switches between the first state (state shown in FIG. 4) and the second state (state shown in FIG. 5). In the first state, the first suction cylinder (34) is communicated with the discharge port of the first pump mechanism (31a) and shut off from the suction port of the second pump mechanism (31b). In the second state, the first suction cylinder (34) is communicated with the suction port of the second pump mechanism (31b) and shut off from the discharge port of the first pump mechanism (31a).

The second direction control valve (33) is connected to the pressurizing passage (42), the depressurizing passage (43), and one end of the second suction cylinder (35).

The second direction control valve (33) switches between the first state (state shown in FIG. 4) and the second state (state shown in FIG. 5). In the first state, the second suction cylinder (35) is communicated with the suction port of the second pump mechanism (31b) and shut off from the discharge port of the first pump mechanism (31a). In the second state, the second suction cylinder (35) is communicated with the discharge port of the first pump mechanism (31a) and shut off from the suction port of the second pump mechanism (31b).

When both the first direction control valve (32) and the second direction control valve (33) are set to the first state, the air circuit (3) is switched to the first connection state (see FIG. 4). In the first connection state, the discharge port of the first pump mechanism (31a) and the first suction cylinder (34) are connected, and the suction port of the second pump mechanism (31b) and the second suction cylinder (35) are connected. Will be done. In the first connection state, the adsorption operation of adsorbing the nitrogen component in the outside air to the adsorbent is performed in the first adsorption cylinder (34), and the nitrogen component adsorbed by the adsorbent is desorbed in the second adsorption cylinder (35). Desorption operation is performed.

When both the first direction control valve (32) and the second direction control valve (33) are set to the second state, the air circuit (3) is switched to the second connection state (see FIG. 5). In the second connection state, the discharge port of the first pump mechanism (31a) and the second suction cylinder (35) are connected, and the suction port of the second pump mechanism (31b) and the first suction cylinder (34) are connected. Will be done. In the second connection state, the suction operation is performed by the second suction cylinder (35), and the desorption operation is performed by the first suction cylinder (34).

(Suction tube)
The first suction cylinder (34) and the second suction cylinder (35) are composed of cylindrical members. The inside of the first adsorption cylinder (34) and the second adsorption cylinder (35) is filled with an adsorbent. The adsorbent has the property of adsorbing the nitrogen component under pressure and desorbing the adsorbed nitrogen component under reduced pressure.

The adsorbent is, for example, a porous zeolite having pores having pores smaller than the molecular diameter of nitrogen molecule (3.0 angstrom) and larger than the molecular diameter of oxygen molecule (2.8 angstrom). When a zeolite having such a pore size is used as an adsorbent, a nitrogen component in the air can be adsorbed.

In the first adsorption cylinder (34) and the second adsorption cylinder (35), when the pressurized outside air is supplied from the air pump (31) and the inside is pressurized, the nitrogen component in the outside air is adsorbed on the adsorbent. .. As a result, oxygen-concentrated air having less nitrogen component than the outside air is generated. Oxygen-concentrated air has a lower nitrogen concentration and a higher oxygen concentration than the outside air.

On the other hand, in the first adsorption cylinder (34) and the second adsorption cylinder (35), when the internal air is sucked by the air pump (31) and the pressure is reduced, the nitrogen component adsorbed by the adsorbent is desorbed. As a result, nitrogen-concentrated air containing more nitrogen components than the outside air is generated. Nitrogen-concentrated air has a higher nitrogen concentration and a lower oxygen concentration than the outside air. In the present embodiment, for example, nitrogen-concentrated air having a component ratio of 92% nitrogen concentration and 8% oxygen concentration is generated.

One end of the oxygen discharge passage (45) is connected to the other end (outlet at the time of pressurization) of the first suction cylinder (34) and the second suction cylinder (35). The oxygen discharge passage (45) guides the oxygen-concentrated air generated from the pressurized outside air to the outside of the container body (2).

One end of the oxygen discharge passage (45) branches into two and is connected to each of the other ends of the first suction cylinder (34) and the second suction cylinder (35). The other end of the oxygen discharge passage (45) opens to the outside of the gas supply unit (30), that is, to the outside of the container body (2). A check valve (61) is provided at each of the branch portion where the oxygen discharge passage (45) is connected to the first suction cylinder (34) and the branch portion connected to the second suction cylinder (35). The check valve (61) prevents the backflow of air from the oxygen discharge passage (45) to the first suction cylinder (34) and the second suction cylinder (35).

A check valve (62) and an orifice (63) are provided in order from one end to the other in the middle of the oxygen discharge passage (45). The check valve (62) prevents the nitrogen-concentrated air from the exhaust connection passage (71), which will be described later, from flowing back to the first suction cylinder (34) and the second suction cylinder (35). The orifice (63) decompresses the oxygen-concentrated air flowing out of the first adsorption cylinder (34) and the second adsorption cylinder (35) before discharging the oxygen-concentrated air to the outside of the refrigerator.

The oxygen discharge passage (45) is a passage for discharging the oxygen-concentrated air generated by the first adsorption cylinder (34) and the second adsorption cylinder (35) to the outside of the refrigerator. A pressure sensor (66) is connected to the oxygen discharge passage (45). The pressure sensor (66) is arranged between the confluence point (P0) of the first suction cylinder (34) and the second suction cylinder (35) and the check valve (62).

The exhaust connection passage (71) is a passage that connects the discharge port of the second pump mechanism (31b) to the oxygen discharge passage (45) on the downstream side of the pressure sensor (66). The check valve (62) is provided between the first connection point (P1) and the second connection point (P2). At the first connection point (P1), the pressure sensor (66) and the oxygen discharge passage (45) are connected. At the second connection point (P2), the oxygen discharge passage (45) and the exhaust connection passage (71) are connected. The check valve (62) allows air flow from the first connection point (P1) to the second connection point (P2) and prohibits air flow in the reverse direction.

(Supply / discharge switching mechanism)
The air circuit (3) is provided with a supply / discharge switching mechanism (70). The supply / discharge switching mechanism (70) switches between a gas supply operation and a gas discharge operation. The gas supply operation is an operation of supplying nitrogen-concentrated air from the first adsorption cylinder (34) and the second adsorption cylinder (35) into the container main body (2). The gas discharge operation is an operation of discharging nitrogen-concentrated air from the first adsorption cylinder (34) and the second adsorption cylinder (35) to the outside of the refrigerator. The supply / discharge switching mechanism (70) has an exhaust connection passage (71), an exhaust on-off valve (72), and a supply on-off valve (73).

One end of the exhaust connection passage (71) is connected to the supply passage (44), and the other end is connected to the oxygen discharge passage (45). The other end of the exhaust connection passage (71) is connected to the oxygen discharge passage (45) on the outside of the refrigerator rather than the orifice (63).

The exhaust on-off valve (72) is provided in the exhaust connection passage (71). The exhaust on-off valve (72) is composed of a solenoid valve arranged in the middle of the exhaust connection passage (71). The exhaust on-off valve (72) switches between an open state that allows the flow of nitrogen-enriched air flowing in from the supply passage (44) and a closed state that blocks the flow of nitrogen-concentrated air. The opening / closing operation of the exhaust on-off valve (72) is controlled by the control unit (55).

The supply on-off valve (73) is provided in the supply passage (44). The supply on-off valve (73) is arranged inside the refrigerator from the connection portion between the supply passage (44) and the exhaust connection passage (71). The supply on-off valve (73) is composed of a solenoid valve that switches between an open state that allows the flow of air to the inside of the refrigerator and a closed state that blocks the flow of air to the inside of the refrigerator. The opening / closing operation of the supply on-off valve (73) is controlled by the control unit (55).

<Exhaust part>
As shown in FIGS. 2 and 4, the exhaust unit (46) has an exhaust passage (46a), an exhaust valve (46b), and a membrane filter (46c). The membrane filter (46c) is provided at the inflow end (inner end of the refrigerator) of the exhaust passage (46a).

The exhaust passage (46a) penetrates the refrigerating casing (12) inside and outside. The exhaust passage (46a) connects the storage space inside the refrigerator (S2) and the space outside the refrigerator.

The exhaust valve (46b) is connected to the exhaust passage (46a). The exhaust valve (46b) is provided inside the exhaust passage (46a). The exhaust valve (46b) is composed of a solenoid valve that switches between an open state that allows the flow of air in the exhaust passage (46a) and a closed state that blocks the flow of air in the exhaust passage (46a). The opening / closing operation of the exhaust valve (46b) is controlled by the control unit (55).

When the exhaust valve (46b) is opened by the control unit (55) while the internal fan (26) is rotating, the air (internal air) in the internal storage space (S2) connected to the internal space is discharged to the outside. Exhaust operation is performed.

Specifically, when the internal fan (26) rotates, the pressure in the secondary space (S22) on the outlet side becomes higher than the pressure in the external space (atmospheric pressure). As a result, when the exhaust valve (46b) is in the open state, the pressure difference (pressure difference between the outer space and the secondary space (S22)) generated between both ends of the exhaust passage (46a) causes the storage. The air (inside air) in the inside storage space (S2) connected to the inside space is discharged to the outside space through the exhaust passage (46a).

<Circuit configuration of sensor unit>
As shown in FIGS. 2 and 4, the sensor unit (50) is provided in the secondary space (S22) on the outlet side of the internal fan (26) in the internal storage space (S2). The sensor unit (50) has an oxygen sensor (51), a carbon dioxide sensor (52), a membrane filter (54), and an exhaust pipe (57).

The oxygen sensor (51) and the carbon dioxide sensor (52) are housed in the sensor casing (90). An introduction port (not shown) that opens into the storage space (S2) inside the refrigerator is provided on the side surface of the sensor casing (90). A membrane filter (54) is attached to the inlet of the sensor casing (90). The air inside the refrigerator that has passed through the membrane filter (54) flows into the inside of the sensor casing (90). The sensor casing (90) is provided with an exhaust port (not shown). An exhaust pipe (57) is connected to the exhaust port.

The oxygen sensor (51) is composed of, for example, a zirconia type sensor. The carbon dioxide sensor (52) is composed of, for example, a non-dispersive infrared (NDIR) sensor. One end of the exhaust pipe (57) is connected to the sensor casing (90). The other end of the exhaust pipe (57) opens near the suction port of the internal fan (26).

The secondary space (S22) and the primary space (S21) of the storage space (S2) in the refrigerator are communicated with each other via a communication passage (58). The communication passage (58) includes a membrane filter (54), an oxygen sensor (51), a carbon dioxide sensor (52), and an exhaust pipe (57).

During the operation of the internal fan (26), the pressure in the primary space (S21) becomes lower than the pressure in the secondary space (S22), and this pressure difference causes the oxygen sensor (51) and the carbon dioxide sensor (51). In the communication passage (58) including 52), the air inside the refrigerator flows from the secondary space (S22) side to the primary space (S21) side.

During the operation of the internal fan (26), the internal air flows into the sensor casing (90) through the membrane filter (54). Inside the sensor casing (90), the air inside the refrigerator passes through the oxygen sensor (51) and the carbon dioxide sensor (52). The oxygen sensor (51) measures the oxygen concentration of the air inside the refrigerator. The carbon dioxide sensor (52) measures the carbon dioxide concentration in the air inside the refrigerator.

The air circuit (3) is provided with a sensor circuit (80). The sensor circuit (80) performs an air supply measurement operation in which the concentration of the nitrogen-concentrated air generated in the first adsorption cylinder (34) and the second adsorption cylinder (35) is measured by the oxygen sensor (51). The sensor circuit (80) includes a branch pipe (81) and a branch on-off valve (82). The sensor circuit (80) branches a part of the air flowing through the supply passage (44) to lead to the oxygen sensor (51) and the carbon dioxide sensor (52).

One end of the branch pipe (81) is connected to the supply passage (44), and the other end is connected to the sensor casing (90). The branch pipe (81) branches from the supply passage (44) in the unit case (36) and communicates with the internal space. A check valve (64) is provided at the other end (inside the refrigerator) of the branch pipe (81). The check valve (64) allows air flow from one end to the other end of the branch pipe (81) and prevents air backflow.

The branch on-off valve (82) is provided inside the unit case (36). The branch on-off valve (82) is composed of a solenoid valve that switches between an open state that allows the air flow of the branch pipe (81) and a closed state that blocks the air flow of the branch pipe (81). The opening / closing operation of the branch on-off valve (82) is controlled by the control unit (55).

When the air supply measurement operation is performed while the operation of the internal fan (26) is stopped, the nitrogen-concentrated air generated by the gas supply unit (30) is sent to the oxygen sensor (51) via the branch pipe (81). Guided, the oxygen concentration of the nitrogen-enriched air is measured by the oxygen sensor (51).

In the air composition adjuster (60), if the measured value of the sensor deviates from the actual value, the concentration adjustment becomes unstable. Therefore, outside air is introduced into the oxygen sensor (51) at a predetermined timing to perform calibration (correction of measured values). During the calibration of the oxygen sensor (51), the outside air pressurized by the air pump (31) passes through the branch pipe (81), bypassing the first suction cylinder (34) and the second suction cylinder (35). Introduced to the oxygen sensor (51) in the sensor casing (90).

The air circuit (3) introduces outside air into the sensor casing (90). The air circuit (3) has a first passage (75) and a second passage (76). The first passage (75) includes an outside air passage (41) and a pressurized passage (42). The second passage (76) includes a bypass passage (47) and a branch pipe (81).

The first passage (75) introduces the outside air into the first suction cylinder (34) and the second suction cylinder (35) by the air pump (31). The second passage (76) branches from the first passage (75) between the air pump (31) and the first suction cylinder (34) and the second suction cylinder (35) to the sensor casing (90). Communicate.

A gas-liquid separator (85) is provided in the second passage (76). The gas-liquid separator (85) removes the moisture in the air introduced into the oxygen sensor (51). A drain pipe (77) is connected to the gas-liquid separator (85). The drain pipe (77) drains the moisture separated from the air.

<Arrangement and structure of sensor unit>
An oxygen sensor (51) and a carbon dioxide sensor (52) are housed inside the sensor casing (90). The gas-liquid separator (85) is fixed to the sensor casing (90).

As shown in FIG. 8, the gas-liquid separator (85) is connected to a branch pipe (81), which is a part of the second passage (76), and a drain pipe (77). The refrigerating casing (12) of the transport refrigerating device (10) is provided with a drain pan (28) for receiving the drain water generated by the transport refrigerating device (10). The drain pipe (77) extends downward from the gas-liquid separator (85) to drain water into the drain pan (28).

The sensor casing (90) is fixed to the refrigerating casing (12) of the transport refrigerating device (10) by a bracket (not shown). In the present embodiment, the sensor casing (90) is located in the storage space (S2) in the refrigerator. The air inside the refrigerator that has passed through the membrane filter (54) flows into the inside of the sensor casing (90).

The gas-liquid separator (85) and the sensor casing (90) are connected by a connecting pipe (59). Inside the sensor casing (90), the air conveyed from the air pump (31) and from which the moisture has been removed by the gas-liquid separator (85) flows in through the connecting pipe (59).

An exhaust pipe (57) is connected to the sensor casing (90). The exhaust pipe (57) is open on the suction port side of the internal fan (26). The air that has flowed into the inside of the sensor casing (90) is discharged from the exhaust pipe (57).

<Control unit>
The control unit (55) controls the concentration adjustment operation for adjusting the oxygen concentration and the carbon dioxide concentration of the air inside the container body (2) to a desired concentration. Specifically, the control unit (55) determines the composition (oxygen concentration and carbon dioxide concentration) of the air inside the container body (2) based on the measurement results of the oxygen sensor (51) and the carbon dioxide sensor (52). The operation of the gas supply unit (30), the exhaust unit (46) and the sensor unit (50) is controlled so as to have a desired composition (for example, oxygen concentration 5%, carbon dioxide concentration 5%).

The control unit (55) includes, for example, a microcomputer that controls each element of the air composition adjusting device (60), and a storage medium such as a memory or a disk in which an implementable control program is stored. The detailed structure and algorithm of the control unit (55) may be any combination of hardware and software.

-Driving operation-
<Operating operation of refrigerant circuit>
In the present embodiment, the unit control unit (100) shown in FIG. 3 executes a cooling operation for cooling the air inside the container body (2).

In the cooling operation, the operation of the compressor (21), expansion valve (23), outside fan (25) and inside fan (26) by the unit control unit (100) is based on the measurement results of the temperature sensor (not shown). The temperature of the air inside the refrigerator is controlled so as to reach a desired target temperature.

In the refrigerant circuit (20), the refrigerant circulates and a steam compression refrigeration cycle is performed. The internal air of the container body (2) guided to the internal storage space (S2) by the internal fan (26) is a refrigerant that flows inside the evaporator (24) when passing through the evaporator (24). Cooled by. The air inside the refrigerator cooled by the evaporator (24) is blown out from the outlet (18b) again into the refrigerator of the container body (2) through the underfloor flow path (19a). As a result, the air inside the container body (2) is cooled.

<Operation of gas supply unit>
(Gas generation operation)
In the gas supply unit (30), the first generation operation and the second generation operation are alternately repeated at a predetermined time to generate nitrogen-enriched air and oxygen-enriched air. The first generation operation is an operation in which the first suction cylinder (34) is pressurized and the second suction cylinder (35) is depressurized at the same time (see FIG. 4). The second generation operation is an operation in which the first suction cylinder (34) is depressurized and the second suction cylinder (35) is pressurized at the same time (see FIG. 5). The switching of each operation is performed by the control unit (55) operating the first direction control valve (32) and the second direction control valve (33).

<< 1st generation operation >>
In the first generation operation, the control unit (55) switches both the first direction control valve (32) and the second direction control valve (33) to the first state shown in FIG. As a result, in the air circuit (3), the first suction cylinder (34) communicates with the discharge port of the first pump mechanism (31a) and is shut off from the suction port of the second pump mechanism (31b), and the second suction is performed. The cylinder (35) communicates with the suction port of the second pump mechanism (31b) and is in the first connection state in which it is cut off from the discharge port of the first pump mechanism (31a).

In the first connection state, the outside air pressurized by the first pump mechanism (31a) is supplied to the first suction cylinder (34), while the second pump mechanism (31b) is supplied from the second suction cylinder (35). Aspirate nitrogen-concentrated air with a higher nitrogen concentration than the outside air and a lower oxygen concentration than the outside air.

Specifically, the first pump mechanism (31a) sucks in the outside air through the outside air passage (41) and pressurizes it, and discharges the pressurized outside air (pressurized air) to the pressurized passage (42). The pressurized air discharged to the pressurized passage (42) flows through the pressurized passage (42). Then, the pressurized air is supplied to the first adsorption cylinder (34) via the pressurized passage (42).

In this way, pressurized air flows into the first adsorption cylinder (34), and the nitrogen component contained in the pressurized air is adsorbed by the adsorbent. During the first generation operation, in the first adsorption cylinder (34), pressurized outside air is supplied from the first pump mechanism (31a), and the nitrogen component in the outside air is adsorbed by the adsorbent, whereby the nitrogen concentration. Is produced oxygen-concentrated air, which is lower than the outside air and has a higher oxygen concentration than the outside air. The oxygen-concentrated air flows out from the first adsorption cylinder (34) to the oxygen discharge passage (45).

The second pump mechanism (31b) sucks air from the second suction cylinder (35). At that time, the nitrogen component adsorbed by the adsorbent of the second adsorption cylinder (35) is sucked by the second pump mechanism (31b) together with air and desorbed from the adsorbent. As described above, during the first generation operation, in the second adsorption cylinder (35), the air inside is sucked by the second pump mechanism (31b), and the nitrogen component adsorbed by the adsorbent is desorbed. As a result, nitrogen-concentrated air containing a nitrogen component desorbed from the adsorbent and having a nitrogen concentration higher than that of the outside air and an oxygen concentration lower than that of the outside air is generated. The nitrogen-concentrated air is sucked into the second pump mechanism (31b), pressurized, and then discharged to the supply passage (44).

<< Second generation operation >>
In the second generation operation, the control unit (55) switches both the first direction control valve (32) and the second direction control valve (33) to the second state shown in FIG. As a result, in the air circuit (3), the first suction cylinder (34) communicates with the suction port of the second pump mechanism (31b) and is shut off from the discharge port of the first pump mechanism (31a), and the second suction is performed. The cylinder (35) communicates with the discharge port of the first pump mechanism (31a) and is in the second connection state in which the suction port of the second pump mechanism (31b) is cut off. In this second connection state, the outside air pressurized by the first pump mechanism (31a) is supplied to the second suction cylinder (35), while the second pump mechanism (31b) is supplied to the first suction cylinder (34). Aspirate nitrogen-concentrated air from.

Specifically, the first pump mechanism (31a) sucks in the outside air through the outside air passage (41) and pressurizes it, and discharges the pressurized outside air (pressurized air) to the pressurized passage (42). The pressurized air discharged to the pressurized passage (42) flows through the pressurized passage (42). Then, similarly to the first generation operation, the pressurized air is supplied to the second suction cylinder (35) via the pressurized passage (42).

In this way, pressurized air flows into the second adsorption cylinder (35), and the nitrogen component contained in the pressurized air is adsorbed by the adsorbent. During the second generation operation, in the second adsorption cylinder (35), pressurized outside air is supplied from the first pump mechanism (31a), and the nitrogen component in the outside air is adsorbed by the adsorbent, whereby nitrogen is produced. Oxygen-enriched air with a lower concentration than the outside air and a higher oxygen concentration than the outside air is produced. The oxygen-concentrated air flows out from the second adsorption cylinder (35) to the oxygen discharge passage (45).

The second pump mechanism (31b) sucks air from the first suction cylinder (34). At that time, the nitrogen component adsorbed by the adsorbent of the first adsorption cylinder (34) is sucked by the second pump mechanism (31b) together with air and desorbed from the adsorbent. As described above, during the second generation operation, the air inside the first suction cylinder (34) is sucked by the second pump mechanism (31b), and the nitrogen component adsorbed by the adsorbent is desorbed. As a result, nitrogen-concentrated air containing a nitrogen component desorbed from the adsorbent and having a nitrogen concentration higher than that of the outside air and an oxygen concentration lower than that of the outside air is generated. The nitrogen-concentrated air is sucked into the second pump mechanism (31b), pressurized, and then discharged to the supply passage (44).

(Gas supply operation and gas discharge operation)
In the gas supply unit (30), the gas supply operation and the gas discharge operation are switched by the supply / discharge switching mechanism (70). The gas supply operation is an operation of supplying the nitrogen-enriched air generated in the air circuit (3) into the refrigerator of the container body (2). The gas discharge operation is an operation in which the generated nitrogen-enriched air is exhausted without being supplied to the inside of the container body (2) for a predetermined time from the start of the desorption operation.

As shown in FIGS. 4 and 5, in the gas supply operation, the exhaust on-off valve (72) is controlled to the closed state and the supply on-off valve (73) is controlled to the open state by the control unit (55). .. As a result, the nitrogen-enriched air alternately generated in the first adsorption cylinder (34) and the second adsorption cylinder (35) is supplied into the refrigerator of the container body (2) through the supply passage (44). The oxygen-concentrated air is discharged to the outside of the refrigerator through the oxygen discharge passage (45).

Although not shown, in the gas discharge operation, the exhaust on-off valve (72) is controlled to the open state and the supply on-off valve (73) is controlled to the closed state by the control unit (55). As a result, the nitrogen-concentrated air that is alternately generated in the first adsorption cylinder (34) and the second adsorption cylinder (35) and discharged to the supply passage (44) is discharged from the oxygen discharge passage (71) to the oxygen discharge passage (71). It flows into 45) and is discharged to the outside of the refrigerator together with the oxygen-concentrated air flowing through the oxygen discharge passage (45).

(Outside air introduction operation)
In the present embodiment, the outside air introduction operation of introducing the outside air into the refrigerator of the container body (2) is also possible. In the outside air introduction operation shown in FIG. 6, the first direction control valve (32) is set to the first state, the second direction control valve (33) is set to the second state, and the bypass on-off valve (48) is opened. .. The supply on-off valve (73) is opened and the branch on-off valve (82) is closed. When the air pump (31) is started in this state, the outside air is composed of an outside air passage (41), a part of the pressurizing passage (42), a bypass passage (47), and a part of the supply passage (44). It flows through the outside air introduction passage (40) shown by the thick solid line. The passage resistance of the outside air introduction passage (40) passes through the first direction control valve (32), the second direction control valve (33), the first suction cylinder (34), and the second suction cylinder (35). This is because it is smaller than the passage resistance. Then, the air having the same composition as the outside air flowing through the outside air introduction passage (40) is pushed into the refrigerator of the container body (2).

<Concentration adjustment operation of air composition adjustment device>
In the present embodiment, the air composition adjusting device (60) uses the control unit (55) to change the composition (oxygen concentration and carbon dioxide concentration) of the air inside the container body (2) to a desired composition (for example, oxygen concentration 5). %, Carbon dioxide concentration 5%). In the concentration adjustment operation, the gas supply unit (30) is used so that the composition of the air inside the container body (2) becomes a desired composition based on the measurement results of the oxygen sensor (51) and the carbon dioxide sensor (52). And the operation of the exhaust unit (46) is controlled.

During the concentration adjustment operation, the control unit (55) controls the branch on-off valve (82) to the closed state. Further, during the concentration adjustment operation, the control unit (55) communicates with the unit control unit (100), and the unit control unit (100) rotates the internal fan (26). As a result, the internal air is supplied to the oxygen sensor (51) and the carbon dioxide sensor (52) by the internal fan (26), and the oxygen concentration and the carbon dioxide concentration of the internal air are measured.

During the concentration adjustment operation, the gas supply operation is performed by alternately repeating the first generation operation and the second generation operation to adjust the oxygen concentration in the refrigerator. At this time, the exhaust valve (46b) of the exhaust unit (46) is controlled to be in the open state, and the amount of nitrogen-enriched air supplied to the inside of the container body (2) by the gas supply operation is taken out of the refrigerator. Discharge. When the oxygen concentration in the refrigerator air drops to a predetermined value (for example, 8%), the control unit (55) stops the operation of the gas supply unit (30) to stop the gas supply operation, and the exhaust valve (46b). Close to stop the exhaust operation. Since the plant (15) breathes in the container body (2), the oxygen concentration in the air inside the container body (2) decreases, eventually reaching 5% of the target oxygen concentration.

In the operation of increasing the oxygen concentration of the air inside the refrigerator, the bypass on-off valve (48) is opened to bypass the outside air sucked by the air pump (31) to the first suction cylinder (34) and the second suction cylinder (35). It can be performed by the outside air introduction operation supplied to the inside of the container body (2). At this time, since the outside air passes through the cooling unit (40a), the temperature rise of the air inside the refrigerator is suppressed.

Although details are omitted, the oxygen concentration (and carbon dioxide concentration) of the air inside the refrigerator can be adjusted by appropriately switching between the gas supply operation, the gas discharge operation, and the outside air introduction operation.

(Air supply measurement operation)
In the present embodiment, an air supply measurement operation for measuring the oxygen concentration of the nitrogen-concentrated air generated in the gas supply unit (30) is performed according to a command from the user or periodically (for example, every 10 days). The air supply measurement operation is performed in parallel when the internal fan (26) is stopped during the gas supply operation such as the above-mentioned concentration adjustment operation or test run.

The control unit (55) controls the branch on-off valve (82) to the open state and the supply on-off valve (73) to the closed state during the gas supply operation. As a result, all of the nitrogen-enriched air flowing through the supply passage (44) flows into the branch pipe (81). The nitrogen-enriched air flowing into the branch pipe (81) is introduced into the oxygen sensor (51), and the oxygen concentration is measured.

By measuring the oxygen concentration of the nitrogen-concentrated air generated in the gas supply unit (30) in this way, the composition (oxygen concentration, nitrogen concentration) of the nitrogen-concentrated air generated in the gas supply unit (30) is desired. It is possible to confirm whether it is in the state of.

(Sensor calibration operation)
In the present embodiment, the sensor calibration operation of FIG. 7 can be performed by introducing outside air into the sensor unit (50) to calibrate the oxygen sensor (51). The sensor calibration operation can be performed, for example, by temporarily stopping the concentration adjustment while cooling the inside of the refrigerator, performing the sensor calibration operation in a short time (about 10 minutes), and then returning to the concentration adjustment operation.

In the sensor calibration operation, the first direction control valve (32) is set to the first state, the second direction control valve (33) is set to the second state, and the bypass on-off valve (48) is opened. The supply on-off valve (73) is closed and the branch on-off valve (82) is opened. When the air pump (31) is started in this state, outside air flows through the first passage (75) and the second passage (76) and is introduced into the sensor unit (50). The oxygen sensor (51) is calibrated so that the detected value indicates the oxygen concentration in the outside air.

During the sensor calibration operation, the outside air passes through the gas-liquid separator (85). Therefore, the oxygen sensor (51) is in contact with the outside air from which at least a part of the moisture has been removed.

<About sensor deterioration>
Next, the deterioration of the oxygen sensor (51) will be described.

(Structure of oxygen sensor)
The oxygen sensor (51) of the present embodiment is a zirconia type sensor. The element of the oxygen sensor (51) is composed of platinum and zirconia. The oxygen sensor (51) measures the oxygen concentration by electrically measuring the amount of oxygen ions moving in the solid electrolytes of platinum and zirconia.

A small amount of metal oxide is added to platinum and zirconia of the oxygen sensor (51) as a bonding aid. Platinum and zirconia are bonded by binding the bonding aids to each other at the interface between platinum and zirconia.

(Issues of deterioration of oxygen sensor)
Corrosive components may be generated from the packaging container housed in the internal space of the container body (2) or the fresh food packed in the packaging container. Here, the corrosive component is a component that corrodes the oxygen sensor (51). The corrosive component circulates in the transportation container (1) together with the air in the refrigerator.

When the oxygen sensor (51) is energized, the oxygen sensor (51) generates heat and becomes hot. On the other hand, when the oxygen sensor (51) switches from the energized state to the non-energized state, the oxygen sensor (51) does not generate heat and the temperature drops. When the temperature of the oxygen sensor (51) decreases, the temperature inside the sensor casing (90) decreases, and the relative humidity inside the sensor casing (90) increases. When the relative humidity in the sensor casing (90) rises, moisture condenses and a water film is formed on the surface of the oxygen sensor (51).

When the corrosive component that has flowed into the sensor casing (90) together with the air inside the refrigerator enters the water film on the surface of the oxygen sensor (51), the corrosive component reacts with the bonding aid of the oxygen sensor (51) in the water film. When the corrosive component reacts with the bonding auxiliary agent of the oxygen sensor (51), the bonding force of the bonding auxiliary agent is weakened, the bonding force of platinum and zirconia is reduced, and the output of the oxygen sensor (51) is reduced. This is the deterioration of the oxygen sensor (51).

Here, the corrosive component contains a sulfur component. Sulfate ions can be mentioned as a corrosive component that easily penetrates into the water film.

<First operation>
The control unit (55) performs the following control while the air composition adjusting device (60) and the transport refrigerating device (10) are in operation.

As shown in FIG. 9, in step ST11, the control unit (55) controls the air composition adjusting device (60) to execute a concentration adjusting operation for adjusting the air composition.

In step ST12, the control unit (55) controls the air pump (31) to convey the concentration-adjusted air to the space inside the container body (2).

In step ST13, the control unit (55) determines whether or not the operation stop command of the air composition adjusting device (60) has been received. If the determination in step ST13 is "YES", branch to step ST14. If the determination in step ST13 is "NO", step ST13 is repeated.

Here, the operation stop command of the air composition adjusting device (60) is output, for example, when the stop button is pressed by the user. At the same time as the operation stop command of the air composition adjusting device (60), the operation stop command of the transport refrigerating device (10) may be output.

In step ST14, the control unit (55) controls the air composition adjusting device (60) to perform the first operation of introducing outside air into the sensor casing (90).

In the first operation, as shown in FIG. 7, the first direction control valve (32) is set to the first state, the second direction control valve (33) is set to the second state, and the bypass on-off valve (48). Is opened. The supply on-off valve (73) is closed and the branch on-off valve (82) is opened. When the air pump (31) is started in this state, outside air flows through the first passage (75) and the second passage (76) and is introduced into the sensor casing (90).

When outside air is introduced inside the sensor casing (90), the corrosive component staying inside the sensor casing (90) is discharged to the outside of the sensor casing (90). Specifically, the corrosive component is discharged to the outside of the sensor casing (90) from the exhaust port. In the present embodiment, the corrosive component that has passed through the exhaust pipe (57) from the exhaust port is discharged to the primary space (S21) on the suction side of the internal fan (26). As a result, it is possible to prevent the sensor (51) from being deteriorated by the corrosive component while the operation of the air composition adjusting device (60) is stopped.

In step ST14, the rotating lid (16C) may be opened and the ventilation port (16D) may be opened to introduce outside air into the interior space through the ventilation port (16D). The outside air introduced into the interior space through the ventilation port (16D) is circulated in the interior space by the interior fan (26). The air inside the refrigerator including the outside air passes through the membrane filter (54) of the sensor casing (90) and flows into the inside of the sensor casing (90).

In this embodiment, the ventilation port (16D) communicates with the primary space (S21) on the suction side of the internal fan (26). Therefore, the outside air taken in from the ventilation port (16D) is introduced from the primary space (S21) to the secondary space (S22) on the outlet side of the casing fan (26) and placed in the secondary space (S22). It flows into the inside of the sensor casing (90). As a result, the corrosive component can be discharged from the inside of the sensor casing (90).

The timing of performing the first operation in conjunction with the operation stop operation of the air composition adjusting device (60) was immediately before the operation of the air composition adjusting device (60) was stopped, and at the same time as the operation stop operation, the operation was stopped. It may be either immediately after.

The control unit (55) may perform the first operation when receiving a stop command for monitoring the oxygen sensor (51). The monitoring of the oxygen sensor (51) is stopped, for example, when the concentration adjustment operation is completed in the air composition adjusting device (60), the air supply measurement operation is completed, and the sensor calibration operation is completed.

<Second operation>
The control unit (55) performs the following control while the air composition adjusting device (60) is stopped and the transport refrigerating device (10) is operated.

As shown in FIG. 10, in step ST21, the unit control unit (100) controls the transport refrigerating device (10) to execute a cooling operation for cooling the internal space of the container body (2).

In step ST22, the unit control unit (100) controls the internal fan (26) to convey the temperature-controlled air to the internal space of the container body (2).

In step ST23, the unit control unit (100) determines whether or not the operation stop command of the transport refrigerating device (10) has been received. If the judgment in step ST23 is "YES", the process branches to step ST24. If the determination in step ST23 is "NO", step ST23 is repeated.

Here, the operation stop command of the transport refrigerating device (10) is output, for example, when the stop button is pressed by the user.

In step ST24, the control unit (55) controls the air composition adjusting device (60) to perform a second operation of introducing outside air into the sensor casing (90).

In the second operation, as shown in FIG. 7, the first direction control valve (32) is set to the first state, the second direction control valve (33) is set to the second state, and the bypass on-off valve (48) is set. Is opened. The supply on-off valve (73) is closed and the branch on-off valve (82) is opened. When the air pump (31) is started in this state, outside air flows through the first passage (75) and the second passage (76) and is introduced into the sensor unit (50).

When outside air is introduced inside the sensor casing (90), the corrosive component staying inside the sensor casing (90) is discharged to the outside of the sensor casing (90). Specifically, the corrosive component is discharged to the outside of the sensor casing (90) from the exhaust port. In the present embodiment, the corrosive component that has passed through the exhaust pipe (57) from the exhaust port is discharged to the primary space (S21) on the suction side of the internal fan (26). As a result, it is possible to prevent the sensor (51) from being deteriorated by the corrosive component while the operation of the freezing device (10) for transportation is stopped.

-Effect of Embodiment 1-
According to the characteristics of the present embodiment, the air whose composition has been adjusted is conveyed to the target space. The concentration of components in the air in the target space is measured by the sensor (51). The sensor (51) is housed in the sensor casing (90). The control unit (55) executes the first operation. The first operation is an operation of introducing outside air into the inside of the sensor casing (90) in conjunction with the operation stop operation of the air composition adjusting device (60).

According to the feature of this embodiment, in the first operation, the outside air can be introduced into the inside of the sensor casing (90) through the passage (75,76) by controlling the transport unit (31).

According to the feature of the present embodiment, in the refrigerating apparatus provided with the air composition adjusting device (60), the deterioration of the sensor (51) due to the corrosive component is suppressed by discharging the corrosive component to the outside of the sensor casing (90). be able to.

According to the feature of this embodiment, the inside and the outside of the target space are communicated by the ventilation port (16D). The ventilation port (16D) is opened and closed by the opening / closing mechanism (16C). The opening / closing mechanism (16C) is in the open state during the first operation.

According to the feature of this embodiment, the control unit (55) executes the second operation. The second operation is an operation of introducing outside air into the inside of the sensor casing (90) in conjunction with the operation of stopping the operation of the refrigerating device (10).

According to the feature of the present embodiment, in the container provided with the refrigerating device (10), the deterioration of the sensor (51) due to the corrosive component can be suppressed by discharging the corrosive component to the outside of the sensor casing (90). ..

According to the feature of this embodiment, the sensor (51) is housed in the sensor casing (90). The air composition adjusting device (60) adjusts the composition of the air and conveys the air to the target space. The outside air is introduced into the sensor casing (90) in conjunction with the stop operation of the air composition adjusting device (60).

<< Embodiment 2 >>
FIG. 11 is a perspective view of the transport refrigerating apparatus according to the second embodiment. Hereinafter, the same parts as those in the first embodiment are designated by the same reference numerals, and only the differences will be described.

As shown in FIG. 11, the sensor casing (90) is arranged outside the refrigerator. Specifically, the sensor casing (90) is arranged on the left side of the electrical component box (17) in the second space (S12) of the storage space (S1) outside the refrigerator. Here, the "left side" means the direction when the surface of the transport refrigerating device (10) exposed to the outside of the transport container (1) is viewed from the front.

As shown in FIG. 12, one end of the air supply pipe (78) is connected to the sensor casing (90). The other end of the air supply pipe (78) opens into the storage space (S2) inside the refrigerator. A membrane filter (54) is attached to the other end of the air supply pipe (78). The air supply pipe (78) is provided to introduce the air inside the refrigerator into the inside of the sensor casing (90) arranged outside the refrigerator.

<< Other Embodiments >>
The embodiment may have the following configuration.

In the above embodiment, the oxygen sensor (51) has been described as a target sensor for suppressing deterioration due to a corrosive component, but the target sensor is not limited to the oxygen sensor (51). The target sensor may be a sensor that measures the concentration of the components of the air inside the refrigerator. For example, the carbon dioxide sensor (52) may be targeted instead of the oxygen sensor (51) or in addition to the oxygen sensor (51). Further, the target sensor may be an ethylene sensor that detects the ethylene concentration or a leak detection sensor that detects the leakage of the refrigerant into the refrigerator. Further, if there is a risk of deterioration of the sensor due to a corrosive component in a configuration in which another sensor is used, that sensor may be targeted.

In the above embodiment, the zirconia type sensor has been described as the target oxygen sensor (51) that suppresses deterioration due to the corrosive component, but the target sensor is not limited to the zirconia type sensor. For example, a galvanic cell-powered sensor may be used.

In the above embodiment, sulfate ion is exemplified as a corrosive component, but the outside air is inside the sensor casing (90) against sulfur components other than sulfate ion, phosphoric acid, calcium, chlorine, ammonia and other corrosive components. May be performed to introduce.

In the above embodiment, one air pump (31) has a first pump mechanism (31a) and a second pump mechanism (31b), but the first pump mechanism (31a) and the second pump mechanism (31b) May consist of two separate air pumps.

The transport unit of the embodiment may be configured by using a blower.

In each of the above embodiments, nitrogen is adsorbed and desorbed by using one first adsorption cylinder (34) and one second adsorption cylinder (35), but the number of adsorption cylinders is one. Not limited to. For example, three suction cylinders (34) and three second suction cylinders (35) may be used to provide a total of six suction cylinders.

The first adsorption cylinder (34) and the second adsorption cylinder (35) as the adjusting unit of the embodiment are not limited to the configuration using an adsorbent such as zeolite, and for example, the permeability of nitrogen and oxygen (and carbon dioxide). ) May be configured to generate nitrogen-concentrated air and oxygen-concentrated air using gas separation membranes having different permeability, and adjust the composition of the air inside the refrigerator by these concentrated air.

In the above embodiment, an example in which the air composition adjusting device (60) is applied to the transport refrigerating device (10) provided in the container body (2) for marine transportation has been described, but the air composition adjusting device (60) has been described. ) Is not limited to this. The air composition adjusting device (60) can be used for adjusting the composition of the air inside the warehouse, for example, a container for land transportation, a simple freezing and refrigerating warehouse, a warehouse at room temperature, etc., in addition to the container for marine transportation. The freezing device may be a device that cools the internal space of a stationary storage (freezing / refrigerating warehouse), not for transportation.

Although the embodiments and modifications have been described above, it will be understood that various changes in the form and details are possible without departing from the purpose and scope of the claims. Further, the above embodiments and modifications may be appropriately combined or replaced as long as the functions of the subject of the present disclosure are not impaired. In addition, the description "first", "second", "third" ... In the description and claims is used to distinguish the words and phrases to which these descriptions are given, and the words and phrases are used. The number and order are not limited.

As described above, the present disclosure is useful for an air composition adjusting device, a refrigerating device, a container, and an air composition adjusting method.

1 Transport container (container)
10 Transport refrigeration equipment (refrigeration equipment)
16C rotary lid (opening and closing mechanism)
16D Ventilation port 31 Air pump (conveyor)
34 1st adsorption cylinder (adjustment part)
35 2nd adsorption cylinder (adjustment part)
51 Oxygen sensor (sensor)
55 Control unit 60 Air composition regulator 75 1st passage 76 2nd passage 90 Sensor casing

Claims

It is an air composition adjusting device that introduces air adjusted to a composition different from the outside air into the target space.
Adjustment unit (34,35) that adjusts the composition of air,
A transport unit (31) that transports air to the target space,
A sensor (51) that measures the concentration of components in the air in the target space, and
A sensor casing (90) accommodating the sensor (51) and
A control unit (55) for executing a first operation of introducing outside air into the inside of the sensor casing (90) is provided in conjunction with the operation stop operation of the air composition adjusting device (60). Air composition regulator.
In claim 1,
A passage (75,76) for introducing outside air is provided inside the sensor casing (90).
The control unit (55) is characterized in that, in the first operation, the transport unit (31) is controlled so as to introduce outside air into the inside of the sensor casing (90) through the passage (75,76). Air composition adjusting device.
A refrigerating apparatus provided with the air composition adjusting apparatus (60) according to claim 1 or 2.
In claim 3,
A ventilation port (16D) that communicates the inside and outside of the target space,
It is equipped with an opening / closing mechanism (16C) that opens and closes the ventilation port (16D).
A refrigerating device characterized in that the opening / closing mechanism (16C) is in an open state during the first operation.
In claim 3 or 4,
The control unit (55) is characterized in that it executes a second operation of introducing outside air into the inside of the sensor casing (90) in conjunction with the operation stop operation of the refrigerating device (10).
A container comprising the refrigerating apparatus (10) according to any one of claims 3 to 5.
It is an air composition adjusting method using an air composition adjusting device (60) that introduces air adjusted to a composition different from the outside air into the target space.
In the air composition adjusting device (60), a sensor (51) for measuring the concentration of components in the air in the target space is housed in a sensor casing (90).
The process of adjusting the composition of the air and
The process of transporting air to the target space and
A method for adjusting an air composition, which comprises a step of introducing outside air into the inside of the sensor casing (90) in conjunction with an operation of stopping the operation of the air composition adjusting device (60).