JP6743480B2 - Gas supply device and container refrigeration device including the same - Google Patents

Description

The present invention relates to a gas supply device for supplying nitrogen-enriched air to the inside of a container by a pump and a refrigerating device for a container provided with the same, and particularly to supplying not only nitrogen-concentrated air but also air having the same composition as the outside air into the inside of the container It is related to the technology.

BACKGROUND ART Conventionally, a container refrigerating apparatus including a refrigerant circuit that performs a refrigeration cycle has been used to cool air in a container used for marine transportation or the like (see, for example, Patent Document 1). Plants such as bananas and avocados are loaded in the container. Even after harvesting, plants breathe, taking up oxygen in the air and releasing carbon dioxide. The respiration of the plant reduces the nutrients and water stored in the plant, and thus the freshness of the plant remarkably decreases as the respiration increases. Therefore, it is preferable that the oxygen concentration in the container is as low as possible so that respiratory disorder does not occur.

Therefore, in Patent Document 1, a gas supply device that generates nitrogen-concentrated air having a nitrogen concentration higher than that of the atmosphere by using an adsorbent that adsorbs nitrogen components in the air when pressurized by an air pump and supplies the air to the inside of the container It is disclosed that the nitrogen-concentrated air is supplied to the inside of the refrigerator to reduce the oxygen concentration of the inside air, thereby reducing the respiration rate of the plant and making it easier to maintain the freshness of the plant.

Japanese Patent No. 2635535

By the way, the oxygen concentration of the indoor air also decreases due to the respiration of plants. Therefore, when the oxygen concentration of the indoor air may decrease to such an extent that the plant causes respiratory disorders, it is necessary to introduce outside air to increase the oxygen concentration of the indoor air. Therefore, in the conventional container refrigeration system, an intake passage that connects the suction side of the internal fan to the outside of the internal refrigerator and an intake valve that opens and closes the intake passage are provided, and the intake valve is opened during rotation of the internal fan. Therefore, the outside air is introduced into the inside of the compartment by utilizing the pressure difference between the suction side of the inside fan and the outside of the compartment due to the rotation of the inside fan.

However, when nitrogen-concentrated air is supplied to the inside of the container in order to reduce the oxygen concentration of the inside air of the container, the pressure inside the container may become higher than the pressure of the outside air. In such a case, even if the intake valve is opened, the air in the refrigerator may be discharged to the outside of the refrigerator via the intake passage instead of introducing the outside air. That is, in the conventional intake section, when the pressure of the air inside the refrigerator is higher than the pressure of the outside air, the outside air cannot be introduced into the inside of the container.

The present invention has been made in view of the above problems, and an object thereof is to provide a gas supply device capable of supplying not only nitrogen-enriched air but also air having the same composition as the outside air to the inside of a container, and a gas supply device including the same. It is to provide a refrigeration device for a container.

1st invention is provided in the container (11) in which the plant (15) which breathes is accommodated, and two adsorption cylinders (34, 35) in which the adsorbent which adsorb|sucks the nitrogen component in air was accommodated inside. And by supplying pressurized air obtained by pressurizing the outside air to one of the adsorption cylinders (34, 35), the adsorption cylinders (34, 35) are pressurized and the air in the adsorption cylinders (34, 35) is compressed. The pressure of the pressurizing pump mechanism (31a) for adsorbing the nitrogen component of the adsorbent to the adsorbent and the adsorbing cylinders (35, 34) are reduced by sucking air from the other adsorbing cylinders (35, 34). And an air pump (31) having a decompression pump mechanism (31b) for desorbing the nitrogen component adsorbed by the adsorbent in the adsorption column (35, 34), and the pressure pump mechanism (31a). ) And the suction passages (42) connected to the suction cylinders (34, 35) and the suction cylinders (34, 35) alternately perform the suction operation and the desorption operation to perform the desorption operation. It is premised on a gas supply device provided with a supply passageway (44) connected to the decompression pump mechanism (31b) so as to supply the nitrogen-enriched air generated by the above into the inside of the container (11).

Further, this gas supply device includes a bypass passage connected to the outlet of the pressure pump mechanism (31a) in the pressure passage (42) and the outlet of the pressure reducing pump mechanism (31b) in the supply passage (44). (47) and a bypass opening/closing valve (48) provided in the bypass passage (47), and supplies the pressurized air that has passed through the pressurizing pump mechanism (31a) to the outside air introduction passage ( 40) is featured.

In the first aspect of the invention, the pressurizing pump mechanism (31a) and the depressurizing pump mechanism (31b) alternately perform the adsorption operation and the desorption operation in the two adsorption columns (34, 35), and the nitrogen generated by the desorption operation is generated. The concentrated air is supplied to the inside of the container (11) through the supply passage. Since the desorption operation is alternately performed by the two adsorption tubes (34, 35), the nitrogen-enriched air is continuously supplied to the inside of the container (11).

Further, according to the first aspect of the present invention, by opening the bypass opening/closing valve (48), the air having the same composition as the outside air passes through the bypass passage (47) forming the outside air introduction passage (40) at the container pressure ( It is pushed into the inside of 11). At that time, since the pressure pump mechanism (31a) is used to push the air into the refrigerator, compared to the case where the pressure reducing pump mechanism (31b) is used to push the air into the refrigerator, The outside air can be introduced quickly.

The second invention is the same as the first invention,
A unit case (36) for accommodating the suction cylinders (34, 35) and the air pump (31) is provided, while a part of the outside air introduction passage (40) passes through a space outside the unit case (36). It is characterized in that a cooling unit (40a) is provided.

In the second aspect of the invention, the cooled air is supplied to the inside of the container (11) through the cooling section (40a) of the outside air introduction passageway (40).

3rd invention is attached to the container (11) in which the plant which breathes is stored, The refrigerant circuit (20) which cools the air in the said container by performing a refrigerating cycle, and the container of the said container (11). A gas supply device (30) for supplying gas into the inside of the container (11), and an exhaust part (46) for discharging the inside air of the container (11) to the outside, and the composition of the inside air of the container (11). It is premised on a container refrigeration system provided with an in-compartment air conditioner (60) for adjusting the temperature. The gas supply device (30) is characterized by being constituted by the gas supply device of the first or second invention.

In the third aspect of the invention, the refrigeration cycle is performed in the refrigerant circuit (20) to cool the air inside the container (11). In addition, the nitrogen-concentrated air generated in the gas supply device (30) of the indoor air conditioning device (60) or the air having the same composition as the outside air is supplied to the container (11), and the exhaust part of the indoor air conditioning device (60). By discharging the air inside the container (11) to the outside by the (46), the composition of the air inside the container (11) is adjusted.

According to the present invention, by switching the flow state of air, not only the nitrogen-enriched air generated in the adsorption cylinders (34, 35) but also the air having the same composition as the outside air is containerized by the pressure pump mechanism (31a). It was decided to configure the gas supply device so that it could be pushed into the chamber of (11). Therefore, even when the pressure inside the container (11) is higher than the pressure of the outside air, air having the same composition as the outside air can be smoothly supplied into the inside of the container (11). Therefore, the composition (oxygen concentration, carbon dioxide concentration) of the inside air can be adjusted to a desired composition quickly and accurately.

According to the second aspect of the invention, since the air cooled through the cooling section (40a) of the outside air introduction passage (40) is supplied to the inside of the container (11), the temperature inside the container rises. Can be suppressed.

According to the third aspect, even when the pressure inside the container (11) is higher than the pressure of the outside air, the air having the same composition as the outside air is smoothly supplied into the inside of the container (11). It was decided to use a gas supply device (30) that can be used in a container refrigeration system. Therefore, it is possible to provide a refrigerating apparatus for a container in which the composition (oxygen concentration, carbon dioxide concentration) of the internal air can be quickly and accurately adjusted to a desired composition. Further, if the cooling part (40a) of the outside air introduction passageway (40) is arranged near the condenser (22) in the outside space of the container (11), the air flowing through the outside air introduction passageway (40) will be condensed ( The air passing through 22) can be effectively cooled, and the temperature inside the refrigerator can be reliably suppressed from rising.

FIG. 1 is a perspective view of a container refrigerating apparatus according to an embodiment of the present invention as seen from the outside of the refrigerator. FIG. 2 is a side sectional view showing a schematic configuration of the container refrigerating apparatus of FIG. FIG. 3 is a piping system diagram showing a configuration of a refrigerant circuit of the container refrigerating apparatus of FIG. 1. FIG. 4 is a piping system diagram showing the configuration of the CA device of the container refrigerating apparatus of FIG. 1, and shows the flow of air in the first operation. FIG. 5 is a piping system diagram showing the configuration of the CA device of the container refrigerating apparatus of FIG. 1, and shows the flow of air in the second operation. FIG. 6 is a piping system diagram showing the configuration of the CA device of the container refrigerating apparatus of FIG. 1, and shows the flow of air in the pressure equalizing operation. FIG. 7 is a piping system diagram showing the configuration of the CA device of the container refrigeration system of FIG. 1, and shows the flow of air in the external air introduction operation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIGS. 1 and 2, the container refrigeration system (10) is provided in a container (storage) (11) used for marine transportation and the like, and cools the air inside the container (11). Is. The plants (15) are stored in a boxed state in the container (11). The plant (15) takes in oxygen (O ₂ ) in the air to release carbon dioxide (CO ₂ ), and breathes, for example, fruits and vegetables such as bananas and avocados, vegetables, grains, bulbs, and fresh flowers. Is.

The container (11) is formed in an elongated box shape with one end surface opened. The container refrigeration system (10) includes a casing (12), a refrigerant circuit (20), and a CA device (in-store air conditioner/Controlled Atmosphere System) (60), and has an open end of the container (11). It is attached so as to close it.

<casing>
As shown in FIG. 2, the casing (12) is provided with an outer wall (12a) located outside the container (11) and an inner wall (12b) located inside the container (11). .. The outer wall (12a) and the inner wall (12b) are made of, for example, an aluminum alloy.

The outer wall (12a) is attached to the peripheral edge of the opening of the container (11) so as to close the opening end of the container (11). The outer wall (12a) is formed so that the lower part thereof bulges inward of the container (11).

The inner wall (12b) is arranged so as to face the outer wall (12a). The inside wall (12b) is bulged inwardly corresponding to the lower part of the outside wall (12a). A heat insulating material (12c) is provided in the space between the inner wall (12b) and the outer wall (12a).

Thus, the lower part of the casing (12) is formed so as to bulge toward the inside of the container (11). As a result, the outside storage space (S1) is formed outside the container (11) in the lower part of the casing (12) and inside the storage space inside the container (11) above the casing (12). (S2) is formed.

As shown in FIG. 1, in the casing (12), two service openings (14) for maintenance are formed side by side in the width direction. The two service openings (14) are closed by first and second service doors (16A, 16B) that can be opened and closed, respectively. Like the casing (12), the first and second service doors (16A, 16B) are each configured by an outer wall of the refrigerator, an inner wall of the refrigerator, and a heat insulating material.

As shown in FIG. 2, a partition plate (18) is arranged inside the container (11). The partition plate (18) is composed of a substantially rectangular plate member, and is erected so as to face the inside surface of the container (11) of the casing (12). The partition plate (18) separates the inside of the container (11) from the inside storage space (S2).

A suction port (18a) is formed between the upper end of the partition plate (18) and the ceiling surface inside the container (11). Air inside the container (11) is taken into the inside storage space (S2) through the suction port (18a).

Further, a partition wall (13) extending in the horizontal direction is provided in the internal storage space (S2). The partition wall (13) is attached to the upper end portion of the partition plate (18), and has an opening in which an internal fan (26) described later is installed. The partition wall (13) has a storage space (S2) in the storage, a primary space (S21) on the suction side of the internal fan (26), and a secondary space (S22) on the outlet side of the internal fan (26). Partition into and. In this embodiment, the internal storage space (S2) is vertically divided by the partition wall (13), the suction-side primary space (S21) is on the upper side, and the outlet-side secondary space (S22) is on the lower side. Formed on the side.

A floorboard (19) is provided inside the container (11) with a gap between the floorboard (19) and the bottom surface of the container (11). Boxed plants (15) are placed on the floor plate (19). An underfloor channel (19a) is formed between the bottom surface of the container (11) and the floor plate (19). A gap is provided between the lower end of the partition plate (18) and the bottom surface inside the container (11), and communicates with the underfloor flow path (19a).

An air outlet (18b) for blowing out the air cooled by the container refrigeration system (10) into the inside of the container (11) is formed on the back side (right side in FIG. 2) of the container (11) in the floor plate (19). Has been done.

<Structure and layout of refrigerant circuit, etc.>
As shown in FIG. 3, the refrigerant circuit (20) includes a compressor (21), a condenser (22), an expansion valve (23), and an evaporator (24) in order by a refrigerant pipe (20a). It is a closed circuit constructed by connecting.

In the vicinity of the condenser (22), the fan motor (25a) outside the refrigerator rotates and drives the air (outside air) in the outside space of the container (11) into the outside storage space (S1) to condense the condenser. An outside fan (25) for sending to (22) is provided. In the condenser (22), heat is generated between the refrigerant pressurized in the compressor (21) and flowing inside the condenser (22) and the outside air sent to the condenser (22) by the outdoor fan (25). Exchange will take place. In the present embodiment, the outdoor fan (25) is composed of a propeller fan.

Near the evaporator (24), an internal fan motor is driven by the internal fan motor (26a) to attract the internal air of the container (11) from the suction port (18a) and blow it out to the evaporator (24). Two (26) are provided. In the evaporator (24), between the refrigerant that is decompressed by the expansion valve (23) and flows inside the evaporator (24) and the in-compartment air sent to the evaporator (24) by the in-compartment fan (26). Heat exchange takes place.

As shown in FIG. 2, the internal fan (26) has a propeller fan (rotary blade) (27a), a plurality of stationary blades (27b), and a fan housing (27c). The propeller fan (27a) is connected to the internal fan motor (26a), is rotationally driven around the rotation axis by the internal fan motor (26a), and blows air in the axial direction. The plurality of stationary blades (27b) are provided on the outlet side of the propeller fan (27a), and rectify the air flow that is blown from the propeller fan (27a) and swirls. The fan housing (27c) is composed of a cylindrical member having a plurality of stationary blades (27b) attached to its inner peripheral surface, extends to the outer circumference of the propeller fan (27a), and surrounds the outer circumference of the propeller fan (27a).

As shown in FIG. 1, the compressor (21) and the condenser (22) are housed in the outside storage space (S1). The condenser (22) has a lower first space (S11) and an upper second space (S12) in the central portion of the outside storage space (S1) in the vertical direction. It is provided so as to be divided into. The first space (S11) includes the compressor (21), an inverter box (29) in which a drive circuit for driving the compressor (21) at a variable speed is housed, and a CA device (60). A gas supply device (30) is provided. On the other hand, the outside space fan (25) and the electrical equipment box (17) are provided in the second space (S12). The first space (S11) is opened to the outside space of the container (11), while the second space (S12) is opened only to the outlet of the outside fan (25) to the outside space. In addition, the space outside the refrigerator is closed by a plate member.

On the other hand, as shown in FIG. 2, the evaporator (24) is stored in the secondary space (S22) of the storage space (S2) in the refrigerator. Two internal fans (26) are provided in the internal storage space (S2) above the evaporator (24) in the width direction of the casing (12) (see FIG. 1 ).

<CA device>
As shown in FIGS. 4 to 7, the CA device (60) provided in the container (11) includes a gas supply device (30), an exhaust unit (46), a sensor unit (50), and a control unit. (55) and adjusts the oxygen concentration and carbon dioxide concentration of the air inside the container (11). In addition, all "concentration" used in the following description refers to "volume concentration".

[Gas supply device]
-Configuration of gas supply device-
The gas supply device (30) is a device that generates nitrogen-enriched air having a low oxygen concentration to be supplied to the inside of the container (11). In the present embodiment, the gas supply device (30) is configured by VPSA (Vacuum Pressure Swing Adsorption). Further, the gas supply device (30) is arranged in the lower left corner portion of the outside storage space (S1) as shown in FIG.

As shown in FIG. 4, the gas supply device (30) includes an air pump (31 ), a first directional control valve (32 ), a second directional control valve (33 ), and an adsorbing nitrogen component in the air. An air circuit (3) connected to the first adsorption cylinder (34) and the second adsorption cylinder (35) having an adsorbent inside, and a unit case accommodating the components of the air circuit (3). (36) and have.

(air pump)
The air pump (31) is provided in the unit case (36), and each of the first pump mechanism (pressurizing pump mechanism) (31a) and the second pump mechanism (depressurizing pump mechanism) sucks, pressurizes and discharges air. It has (31b). The first pump mechanism (31a) and the second pump mechanism (31b) are connected to the drive shaft of the motor (31c), and are rotationally driven by the motor (31c) to suck, pressurize, and discharge air. To do.

The suction port of the first pump mechanism (31a) is connected to one end of an outside air passage (41) provided so as to penetrate the unit case (36) in and out. A membrane filter (76) having air permeability and waterproofness is provided at the other end of the outside air passage (41). The outside air passageway (41) is composed of a flexible tube. Although not shown, the other end of the outside air passage (41) provided with the membrane filter (76) is provided in the second space (S12) above the condenser (22) of the outside storage space (S1). ing. With such a configuration, the first pump mechanism (31a) causes water to flow into the unit case (36) from the outside through the membrane filter (76) provided at the other end of the outside air passageway (41). The outside air that has been removed is sucked in and pressurized.

On the other hand, one end of the pressure passage (42) is connected to the discharge port of the first pump mechanism (31a). The other end of the pressurizing passage (42) is branched into two on the downstream side and is connected to each of the first directional control valve (32) and the second directional control valve (33). The pressurizing passageway (42) is composed of a resin tube.

One end of the decompression passageway (43) is connected to the suction port of the second pump mechanism (31b). The other end of the decompression passage (43) is divided into two on the upstream side and is connected to each of the first directional control valve (32) and the second directional control valve (33). On the other hand, one end of the supply passageway (44) is connected to the discharge port of the second pump mechanism (31b). The other end of the supply passage (44) opens in the secondary space (S22) on the outlet side of the internal fan (26) in the internal storage space (S2) of the container (11). The other end of the supply passage (44) is provided with a check valve (65) that allows only the air to flow from one end to the other and prevents the backflow of the air.

The first pump mechanism (31a) and the second pump mechanism (31b) of the air pump (31) are oilless pumps that do not use lubricating oil. Further, on the side of the air pump (31), two blower fans (49) for cooling the air pump (31) by blowing air toward the air pump (31) are provided.

As described above, the air pump (31) pressurizes the adsorption cylinders (34, 35) by supplying pressurized air to the adsorption cylinders (34, 35), and the adsorption cylinders (34, 35). In the first pump mechanism (31a), which is a pressure pump mechanism for performing the adsorption operation of adsorbing the nitrogen component in the pressurized air to the adsorbent, and in the other adsorption cylinder (35, 34) sucking air By doing so, the pressure of the adsorption cylinder (35, 34) is reduced, and the decompression operation for desorbing the nitrogen component adsorbed by the adsorbent in the adsorption cylinder (35, 34) is performed. It has a mechanism (31b).

In the supply passage (44), the adsorption operation and the desorption operation are alternately performed in the adsorption cylinders (34, 35), and the nitrogen enriched air having a desired composition generated by the desorption operation is supplied to the container (11). It is a passage that supplies to the inside of.

(Outside air introduction passage)
The outlet of the pressure pump mechanism (31a) in the pressure passage (42) (between the pressure pump mechanism (31a) and the directional control valve (32, 33)) and the pressure reduction pump mechanism in the supply passage (44) ( The outlet of 31b) is connected by a bypass passage (47). The bypass passage (47) is provided with a bypass opening/closing valve (48) whose opening/closing is controlled by the controller (55). In the present embodiment, the outside air passage (41), a part of the pressurization passage (42), the bypass passage (47) having the bypass opening/closing valve (48), and the supply passage (44). The outside air introduction passageway (40) is configured by a part thereof. The outside air introduction passage (40) is a passage for supplying the compressed air (air having the same composition as the outside air) that has passed through the pressure pump mechanism (31a) to the inside of the refrigerator. Further, the outside air introduction passageway (40) is provided with a cooling section (40a) passing through a space outside the unit case (36). The cooling section (40a) is arranged near the condenser (22). In this embodiment, a part of the pressurizing passage (42) is configured as the cooling unit (40a), but the bypass passage (47) may be configured as the cooling unit (40a), for example.

(Direction control valve)
The first directional control valve (32) and the second directional control valve (33) are provided between the air pump (31) and the first adsorption cylinder (34) and the second adsorption cylinder (35) in the air circuit (3). The connection state between the air pump (31) and the first adsorption cylinder (34) and the second adsorption cylinder (35) is switched to three connection states (first to third connection states) described later. This switching operation is controlled by the control section (55).

Specifically, the first directional control valve (32) was connected to the pressure passage (42) connected to the discharge port of the first pump mechanism (31a) and the suction port of the second pump mechanism (31b). It is connected to the decompression passage (43) and one end of the first adsorption cylinder (34) (inlet at the time of pressurization). This first directional control valve (32) connects the first adsorption cylinder (34) to the discharge port of the first pump mechanism (31a) and shuts off the suction port of the second pump mechanism (31b) in the first state ( 4) and a second state in which the first adsorption cylinder (34) is communicated with the suction port of the second pump mechanism (31b) and is blocked from the discharge port of the first pump mechanism (31a) (see FIG. 5). (State shown).

The second directional control valve (33) includes a pressurizing passage (42) connected to the discharge port of the first pump mechanism (31a) and a depressurizing passage (43) connected to the suction port of the second pump mechanism (31b). ) And one end of the second adsorption cylinder (35). The second directional control valve (33) allows the second adsorption cylinder (35) to communicate with the suction port of the second pump mechanism (31b) and shuts off the discharge port of the first pump mechanism (31a) in the first state ( 4) and a second state in which the second suction cylinder (35) is connected to the discharge port of the first pump mechanism (31a) and is blocked from the suction port of the second pump mechanism (31b) (see FIG. 5). (State shown).

When both the first directional control valve (32) and the second directional control valve (33) are set to the first state, the air circuit (3) causes the discharge port of the first pump mechanism (31a) and the first adsorption cylinder (34). ) Is connected, and the suction port of the second pump mechanism (31b) and the second suction cylinder (35) are connected to each other (see FIG. 4). In this state, the first adsorption cylinder (34) performs an adsorption operation for adsorbing the nitrogen component in the outside air to the adsorbent, and the second adsorption cylinder (35) desorbs the nitrogen component adsorbed by the adsorbent. Is done.

When both the first directional control valve (32) and the second directional control valve (33) are set to the second state, the air circuit (3) causes the discharge port of the first pump mechanism (31a) and the second adsorption cylinder (35). ) And the suction port of the second pump mechanism (31b) and the first adsorption cylinder (34) are connected to each other (see FIG. 5). In this state, the suction operation is performed in the second suction cylinder (35) and the desorption operation is performed in the first suction cylinder (34).

When the first directional control valve (32) is set to the first state and the second directional control valve (33) is set to the second state, the air circuit (3) is connected to the discharge port of the first pump mechanism (31a). Switching to the third connection state in which the first suction cylinder (34) is connected and the discharge port of the first pump mechanism (31a) and the second suction cylinder (35) are connected (see FIG. 6 ). In this state, both the first suction cylinder (34) and the second suction cylinder (35) are connected to the discharge port of the first pump mechanism (31a), and the first pump mechanism (31a) causes the first suction cylinder (34a). ) And the second adsorption cylinder (35) are supplied with pressurized outside air. That is, in the third connection state, the suction operation is performed by both the first suction cylinder (34) and the second suction cylinder (35).

Further, when the bypass opening/closing valve (48) is opened in this state as shown in FIG. 7, the passage resistance of the bypass passage (47) causes the passage resistance of the first directional control valve (32), the second directional control valve (33), Since it is smaller than the passage resistance of the flow passage that passes through the first adsorption cylinder (34) and the second adsorption cylinder (35), most of the air flows through the outside air introduction passage (40) and the pump pressure of the first pump mechanism (31a). It is pushed into the refrigerator by.

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

The adsorbent filled in the first adsorption column (34) and the second adsorption column (35) is, for example, smaller than the molecular diameter of nitrogen molecules (3.0 angstroms) and the molecular diameter of oxygen molecules (2.8 angstroms). ) Is larger than that of the porous zeolite. If the adsorbent is composed of zeolite having such a pore size, it is possible to adsorb nitrogen components in the air.

In addition, since the cations are present in the pores of the zeolite and an electric field is present to generate polarity, the zeolite has a property of adsorbing polar molecules such as water molecules. Therefore, not only nitrogen in the air but also water (water vapor) in the air is adsorbed by the adsorbent made of zeolite filled in the first adsorption cylinder (34) and the second adsorption cylinder (35). Then, the water adsorbed on the adsorbent is desorbed from the adsorbent together with the nitrogen component by the desorption operation. Therefore, nitrogen-concentrated air containing water is supplied to the inside of the container (11), and the humidity inside the container can be increased. Furthermore, since the adsorbent is regenerated, the life of the adsorbent can be extended.

With such a configuration, in the first adsorption cylinder (34) and the second adsorption cylinder (35), when the pressurized outside air is supplied from the air pump (31) to pressurize the inside, the adsorbent absorbs the outside air. The nitrogen component inside is adsorbed. As a result, since the nitrogen component is smaller than that in the outside air, oxygen-enriched air having a lower nitrogen concentration and a higher oxygen concentration than the outside air is generated. On the other hand, in the first adsorption cylinder (34) and the second adsorption cylinder (35), when the internal air is sucked and depressurized by the air pump (31), the nitrogen component adsorbed by the adsorbent is desorbed. As a result, nitrogen-enriched air having a higher nitrogen concentration and a lower oxygen concentration than the outside air is generated by containing more nitrogen components 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.

At the other end (outlet at the time of pressurization) of the first adsorption cylinder (34) and the second adsorption cylinder (35), the first pump in the first adsorption cylinder (34) and the second adsorption cylinder (35) One end of an oxygen discharge passage (45) for guiding the oxygen-enriched air generated by supplying the outside air pressurized by the mechanism (31a) to the outside of the container (11) is connected. One end of the oxygen discharge passageway (45) is branched into two and is connected to each of the other end portions of the first adsorption cylinder (34) and the second adsorption cylinder (35). The other end of the oxygen discharge passageway (45) is open outside the gas supply device (30), that is, outside the container (11). From the oxygen discharge passageway (45) to the portion of the oxygen discharge passageway (45) connected to the other end of the first adsorption cylinder (34) and the portion connected to the other end of the second adsorption cylinder (35). Check valves (61) for preventing backflow of air to the first adsorption cylinder (34) and the second adsorption cylinder (35) are provided, respectively.

A check valve (62) and an orifice (63) are sequentially provided in the middle of the oxygen discharge passageway (45) from one end to the other end. The check valve (62) prevents the nitrogen-concentrated air from flowing backward from the exhaust connection passage (71) to the first adsorption cylinder (34) and the second adsorption cylinder (35). The orifice (63) reduces the pressure of the oxygen-enriched air flowing out from the first adsorption cylinder (34) and the second adsorption cylinder (35) before being discharged to the outside of the refrigerator.

As described above, the oxygen discharge passage (45) is a passage for discharging the oxygen-enriched air that has passed through the adsorption cylinders (34, 35) in the adsorption operation to the outside of the refrigerator. A pressure sensor (90) is provided in the oxygen discharge passage (45) between the confluence point (P0) of the first adsorption cylinder (34) and the second adsorption cylinder (35) and the check valve (62). ing.

The exhaust connection passage (71) is a passage that connects the discharge port of the decompression pump mechanism (31b) to the oxygen discharge passage (45) on the downstream side of the pressure sensor (90). In 62), the first connection point (P1) where the pressure sensor (90) and the oxygen discharge passage (45) are connected, and the oxygen discharge passage (45) and the exhaust connection passage (71) are connected. It is provided between the second connection point (P2) and allows the air flow from the first connection point (P1) to the second connection point (P2) while prohibiting the air flow in the opposite direction.

(Supply/discharge switching mechanism)
The air circuit (3) is provided for switching between a gas supply operation described later for supplying the generated nitrogen-enriched air into the container (11) and a gas discharge operation for discharging the generated nitrogen-enriched air to the outside of the container. A supply/discharge switching mechanism (70) is provided. The supply/discharge switching mechanism (70) has an exhaust connection passage (71), an exhaust on-off valve (72), and a supply-side on-off valve (73).

The exhaust connection passageway (71) has one end connected to the supply passageway (44) and the other end connected to the oxygen discharge passageway (45). The other end of the exhaust connection passage (71) is connected to the outside of the refrigerator with respect to the orifice (63) of the oxygen discharge passage (45).

The exhaust on-off valve (72) is provided in the exhaust connection passageway (71). The exhaust on-off valve (72) has an open state that allows the flow of the nitrogen-enriched air that has flowed in from the supply passage (44) and a closed state that shuts off the flow of the nitrogen-concentrated air in the middle of the exhaust connection passage (71). It is composed of a solenoid valve that switches to the state. The opening/closing operation of the exhaust on-off valve (72) is controlled by the controller (55).

The supply-side opening/closing valve (73) is provided on the other end side (inside the refrigerator) with respect to the connection portion of the supply passage (44) to which the exhaust connection passage (71) is connected. The supply side opening/closing valve (73) is in an open state that allows the nitrogen-concentrated air to flow to the inside of the compartment inside the compartment of the supply passage (44) with respect to the connection portion of the exhaust connection passage (71), and the nitrogen-concentrated air. It is configured by a solenoid valve that switches to a closed state that shuts off the circulation of the inside of the refrigerator. The opening/closing operation of the supply side opening/closing valve (73) is controlled by the controller (55).

(Measurement unit)
The air circuit (3) measures the concentration of the generated nitrogen-enriched air by using an oxygen sensor (51) of a sensor unit (50), which will be described later, provided inside the container (11). A measurement unit (80) is provided for performing. The measurement unit (80) includes a branch pipe (gas concentration measurement passage) (81) and a gas concentration measurement opening/closing valve (82), and branches a part of the nitrogen-enriched air flowing through the supply passage (44). It is configured to lead to an oxygen sensor (gas concentration measuring sensor) (51). That is, the gas concentration measuring passage (81) is provided with the gas concentration measuring on-off valve (82) and the gas concentration measuring sensor (51) in this order from the upstream side.

Specifically, the branch pipe (81) has one end connected to the supply passage (44) and the other end connected to the oxygen sensor (51). In the present embodiment, the branch pipe (81) is provided so as to branch from the supply passage (44) in the unit case (36) to communicate with the inside of the compartment and to extend inside and outside the unit case (36). There is. A check valve (64) is provided at the other end (inside the compartment) of the branch pipe (81) to allow only air to flow from one end to the other end and to prevent backflow of air. ..

The gas concentration measuring on-off valve (82) is provided inside the unit case (36) of the branch pipe (81). The gas concentration measuring on-off valve (82) is an electromagnetic switch that switches between an open state that allows the flow of nitrogen-enriched air in the branch pipe (81) and a closed state that blocks the flow of nitrogen-enriched air in the branch pipe (81). It is composed of valves. The opening/closing operation of the gas concentration measuring on-off valve (82) is controlled by the controller (55). Although the details will be described later, the gas concentration measuring on-off valve (82) is opened only when the air supply measuring operation described later is executed, and is closed in other modes.

-Operation of gas supply device-
(Gas generation operation)
In the gas supply device (30), the first adsorption cylinder (34) is pressurized and at the same time the second adsorption cylinder (35) is decompressed (see FIG. 4) and the first adsorption cylinder (34). ) Is depressurized and the second operation (see FIG. 5) in which the second adsorption cylinder (35) is pressurized is alternately repeated for a predetermined time (for example, 14.5 seconds). , Nitrogen-enriched air and oxygen-enriched air are generated. Further, in the present embodiment, a pressure equalizing operation in which both the first adsorption cylinder (34) and the second adsorption cylinder (35) are pressurized between the first operation and the second operation (see FIG. 6). Reference) is performed for a predetermined time (for example, 1.5 seconds). The switching of each operation is performed by the control unit (55) operating the first directional control valve (32) and the second directional control valve (33).

<<First operation>>
In the first operation, the control unit (55) switches both the first directional control valve (32) and the second directional control valve (33) to the first state shown in FIG. As a result, in the air circuit (3), the first adsorption cylinder (34) communicates with the discharge port of the first pump mechanism (31a) and is blocked from the suction port of the second pump mechanism (31b), and the second adsorption mechanism The cylinder (35) is in communication with the suction port of the second pump mechanism (31b) and is in the first connection state in which it is blocked from the discharge port of the first pump mechanism (31a). In this first connected state, the outside air pressurized by the first pump mechanism (31a) is supplied to the first adsorption cylinder (34), while the second pump mechanism (31b) is compressed by the second adsorption cylinder (35). The nitrogen-concentrated air whose nitrogen concentration is higher than that of the outside air and whose oxygen concentration is lower than that of the outside air is sucked from the air.

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

In this way, the pressurized air flows into the first adsorption cylinder (34), and the nitrogen component contained in the pressurized air is adsorbed by the adsorbent. Thus, during the first operation, the first adsorption cylinder (34) is supplied with the pressurized outside air from the first pump mechanism (31a), and the nitrogen component in the outside air is adsorbed by the adsorbent. As a result, oxygen-enriched air having a nitrogen concentration lower than the outside air and an oxygen concentration higher than the outside air is generated. The oxygen-enriched air flows out of the first adsorption column (34) into the oxygen discharge passage (45).

On the other hand, the second pump mechanism (31b) sucks air from the second adsorption cylinder (35). At that time, the nitrogen component adsorbed by the adsorbent of the second adsorption column (35) is sucked by the second pump mechanism (31b) together with air and desorbed from the adsorbent. Thus, during the first 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, so that the adsorbent is desorbed. Nitrogen-enriched air that contains nitrogen components desorbed from the air and that has a higher nitrogen concentration than the outside air and a lower oxygen concentration than the outside air is generated. The nitrogen-concentrated air is sucked into the second pump mechanism (31b), pressurized, and then discharged into the supply passage (44).

<<Second motion>>
In the second operation, the control unit (55) switches both the first directional control valve (32) and the second directional control valve (33) to the second state shown in FIG. As a result, in the air circuit (3), the first adsorption cylinder (34) communicates with the suction port of the second pump mechanism (31b) and is blocked from the discharge port of the first pump mechanism (31a), and the second adsorption mechanism The cylinder (35) communicates with the discharge port of the first pump mechanism (31a) and enters the second connection state in which it is blocked from the suction port of the second pump mechanism (31b). In this second connected state, the outside air pressurized by the first pump mechanism (31a) is supplied to the second adsorption cylinder (35), while the second pump mechanism (31b) is compressed by the first adsorption cylinder (34). Aspirate nitrogen enriched air from.

Specifically, the first pump mechanism (31a) sucks and pressurizes the outside air through the outside air passage (41), and discharges the pressurized outside air (pressurized air) to the pressurizing passage (42). The pressurized air discharged into the pressure passage (42) flows through the pressure passage (42). Then, also in the second operation, as in the first operation, the pressurized air is supplied to the second adsorption cylinder (35) through the pressure passage (42).

In this way, the pressurized air flows into the second adsorption column (35), and the nitrogen component contained in the pressurized air is adsorbed by the adsorbent. Thus, during the second operation, in the second adsorption cylinder (35), the pressurized outside air is supplied from the first pump mechanism (31a) and the nitrogen component in the outside air is adsorbed by the adsorbent. As a result, oxygen-enriched air having a nitrogen concentration lower than the outside air and an oxygen concentration higher than the outside air is generated. The oxygen-enriched air flows out of the second adsorption column (35) into the oxygen discharge passage (45).

On the other hand, the second pump mechanism (31b) sucks air from the first adsorption cylinder (34). At that time, the nitrogen component adsorbed by the adsorbent of the first adsorption column (34) is sucked by the second pump mechanism (31b) together with air and desorbed from the adsorbent. Thus, during the second operation, in the first adsorption cylinder (34), the air inside is sucked by the second pump mechanism (31b) and the nitrogen component adsorbed by the adsorbent is desorbed, so that the adsorbent is desorbed. Nitrogen-enriched air that contains nitrogen components desorbed from the air and that has a higher nitrogen concentration than the outside air and a lower oxygen concentration than the outside air is generated. The nitrogen-concentrated air is sucked into the second pump mechanism (31b), pressurized, and then discharged into the supply passage (44).

<Equalizing action>
As shown in FIG. 6, in the pressure equalizing operation, the control unit (55) switches the first directional control valve (32) to the first state while the second directional control valve (33) switches to the second state. To be As a result, in the air circuit (3), the first adsorption cylinder (34) and the second adsorption cylinder (35) both communicate with the discharge port of the first pump mechanism (31a) and the second pump mechanism (31b). The third connection state is obtained in which the suction port is cut off. In the third connected state, the outside air pressurized by the first pump mechanism (31a) is supplied to both the first adsorption cylinder (34) and the second adsorption cylinder (35), while the second pump mechanism (31b). ) Draws in the nitrogen-enriched air remaining in the decompression passageway (43).

Specifically, the first pump mechanism (31a) sucks and pressurizes the outside air through the outside air passage (41), and discharges the pressurized outside air (pressurized air) to the pressurizing passage (42). The pressurized air discharged into the pressure passage (42) flows through the pressure passage (42). Then, the pressurized air is supplied to both the first adsorption cylinder (34) and the second adsorption cylinder (35) via the pressure passage (42).

In the first adsorption cylinder (34) and the second adsorption cylinder (35), the nitrogen component contained in the inflowing pressurized air is adsorbed by the adsorbent, and oxygen enriched air is generated. The oxygen-enriched air flows out from the first adsorption cylinder (34) and the second adsorption cylinder (35) to the oxygen discharge passage (45).

On the other hand, the second pump mechanism (31b) is shut off from the first adsorption cylinder (34) and the second adsorption cylinder (35). Therefore, during the pressure equalizing operation, new nitrogen-enriched air is not newly generated in the first adsorption cylinder (34) and the second adsorption cylinder (35), and the second pump mechanism (31b) is provided with the decompression passage ( The nitrogen-concentrated air remaining in 43) is sucked and pressurized, and then discharged into the supply passageway (44).

By the way, as described above, during the first operation, the first suction cylinder (34) is pressurized by the first pump mechanism (31a) to perform the suction operation, and the second suction cylinder (35) moves to the second suction cylinder (35). The pump mechanism (31b) reduces the pressure to perform the desorption operation. On the other hand, during the second operation, the second suction cylinder (35) is pressurized by the first pump mechanism (31a) to perform the suction operation, and the first suction cylinder (34) has the second pump mechanism (31b). The pressure is reduced by the desorption operation. Therefore, when the first operation is switched to the second operation or the second operation is switched to the first operation without interposing the pressure equalizing operation described above, immediately after the switching, the desorption operation in the adsorption cylinder that was performing the desorption operation before the switching is performed. Since the pressure is extremely low, it takes time for the pressure in the adsorption cylinder to rise, and the adsorption operation is not performed immediately.

Therefore, in the present embodiment, when switching from the first operation to the second operation and when switching from the second operation to the first operation, the air circuit (3) is switched to the third connection state and the first adsorption cylinder (34 ) And the second adsorption cylinder (35) are communicated with each other via the first directional control valve (32) and the second directional control valve (33). As a result, the internal pressures of the first adsorption cylinder (34) and the second adsorption cylinder (35) quickly become equal to each other (intermediate pressure between the internal pressures (high pressure for adsorption operation and low pressure for desorption operation). Intermediate pressure))). By such a pressure equalizing operation, the pressure in the adsorption cylinder, which was decompressed by the second pump mechanism (31b) before the switching and was performing the desorption operation, quickly rises, so that the pressure to the first pump mechanism (31a) is increased. After the connection, the suction operation is performed immediately.

In this manner, in the gas supply device (30), the first operation and the second operation are alternately repeated while sandwiching the pressure equalizing operation to generate nitrogen-enriched air and oxygen-enriched air in the air circuit (3). It

(Gas supply operation/gas discharge operation)
Further, in the gas supply device (30), the supply/discharge switching mechanism (70) starts the gas supply operation for supplying the nitrogen-enriched air generated in the air circuit (3) to the inside of the container (11) and the desorption operation. During a predetermined time from the point of time, the gas discharge operation of discharging the generated nitrogen-enriched air without supplying it to the inside of the container (11) is switched.

<Gas supply operation>
As shown in FIGS. 4 and 5, in the gas supply operation, the control part (55) controls the exhaust on-off valve (72) to be in the closed state and the supply side on-off valve (73) to be in the open state. .. As a result, the nitrogen-enriched air alternately generated in the first adsorption column (34) and the second adsorption column (35) is supplied to the inside of the container (11) through the supply passage (44), and the oxygen-enriched air is formed. Is discharged to the outside of the refrigerator through the oxygen discharge passage (45).

<Gas discharge operation>
Although not shown, in the gas discharging operation, the control part (55) controls the exhaust on-off valve (72) to be in the open state and the supply side on-off valve (73) to be in the closed state. As a result, the nitrogen-concentrated air alternately generated in the first adsorption cylinder (34) and the second adsorption cylinder (35) and discharged into the supply passage (44) is supplied with the supply-side on-off valve (73) in the supply passage (44). ) From the inside of the refrigerator, and flows into the exhaust connection passageway (71). The nitrogen-concentrated air that has flowed into the exhaust connection passage (71) flows into the oxygen discharge passage (45) and is discharged to the outside of the refrigerator together with the oxygen-concentrated air that flows through the oxygen discharge passage (45).

(Open air introduction operation)
In this embodiment, the outside air introduction operation of introducing outside air into the inside of the container (11) can be performed. In the outside air introduction operation shown in FIG. 7, the first directional control valve (32) is set to the first state, the second directional control valve (33) is set to the second state, and the bypass opening/closing valve (48) is opened. .. When the air pump (31) is started in this state, the outside air is composed of the outside air passage (41), a part of the pressurizing passage (42), the 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. This is because the passage resistance of the outside air introduction passage (40) is smaller than the passage resistance of the passage passing through the direction switching valves (32, 33) and the adsorption cylinders (34, 35). The air having the same composition as the outside air flowing through the outside air introduction passage (40) is pushed into the inside of the container (11). At this time, the air having the same composition as the outside air is cooled in the cooling section (40a) and then supplied into the refrigerator. In this embodiment, since the outside air is pushed into the refrigerator by using the first pump mechanism (31a), compared to the case where the outside air is pushed into the refrigerator by using the second pump mechanism (31b), The outside air can be quickly introduced into the refrigerator.

[Exhaust part]
-Exhaust unit configuration-
As shown in FIG. 2 and FIG. 4, the exhaust part (46) includes an exhaust passage (46a) connecting the internal storage space (S2) and the external storage space, and an exhaust valve (46a) connected to the exhaust passage (46a). 46b) and a membrane filter (46c) provided at the inflow end (end inside the chamber) of the exhaust passage (46a). The exhaust passage (46a) is provided so as to penetrate the casing (12) in and out. The exhaust valve (46b) is provided inside the exhaust passage (46a) and has an open state that allows air to flow in the exhaust passage (46a) and a closed state that blocks air from flowing in the exhaust passage (46a). It is composed of a solenoid valve that switches to. The opening/closing operation of the exhaust valve (46b) is controlled by the control unit (55).

-Exhaust section operation-
By opening the exhaust valve (46b) by the control unit (55) while the internal fan (26) is rotating, the air in the internal storage space (S2) connected to the internal storage (air in the internal storage) is discharged to the outside of the internal storage. The exhaust operation is performed.

Specifically, when the internal fan (26) rotates, the pressure in the outlet side secondary space (S22) 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 outside space and the secondary space (S22)) generated between both ends of the exhaust passage (46a) causes Air in the storage space (S2) connected to the inside (air in the storage) is discharged to the space outside the storage through the exhaust passage (46a).

[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), a communication pipe (56), and an exhaust pipe (57).

The oxygen sensor (51) is composed of a galvanic battery type sensor. On the other hand, the carbon dioxide sensor (52) is composed of a non-dispersive infrared (NDIR) sensor. A branch pipe (81) of the measurement unit (80) is connected to the oxygen sensor (51), and the oxygen sensor (51) and the carbon dioxide sensor (52) are connected by a communication pipe (56). Further, one end of an exhaust pipe (57) is connected to the carbon dioxide sensor (52), and the other end of the exhaust pipe (57) is open near the suction port of the internal fan (26). The oxygen sensor (51) has a suction port for taking in the surrounding air, and the membrane filter (54) is provided at the suction port.

With such a configuration, the secondary space (S22) and the primary space (S21) of the internal storage space (S2) are the membrane filter (54), oxygen sensor (51), connecting pipe (56), carbon dioxide. The sensor (52) and the exhaust pipe (57) communicate with each other via an air passageway (58). Therefore, during operation of the internal fan (26), the pressure in the primary space (S21) becomes lower than the pressure in the secondary space (S22). Air in the refrigerator flows from the secondary space (S22) side to the primary space (S21) side in the air passageway (58) connected to the carbon sensor (52). In this way, the air in the refrigerator passes through the oxygen sensor (51) and the carbon dioxide sensor (52) in order, the oxygen concentration of the air in the refrigerator is measured by the oxygen sensor (51), and the oxygen sensor (52) is measured. The carbon dioxide concentration of the air in the refrigerator is measured. On the other hand, while the internal fan (26) is stopped and the air supply measurement operation described later is performed, the nitrogen-concentrated air generated in the gas supply device (30) is supplied to the oxygen sensor via the branch pipe (81). Guided to (51), the oxygen sensor (51) measures the oxygen concentration of the nitrogen-enriched air.

[Control part]
The control unit (55) is configured to execute a concentration adjusting operation for adjusting the oxygen concentration and the carbon dioxide concentration of the air inside the container (11) to desired concentrations. Specifically, the control unit (55) determines the composition (oxygen concentration and carbon dioxide concentration) of the air inside the container (11) based on the measurement results of the oxygen sensor (51) and the carbon dioxide sensor (52). The operations of the gas supply device (30) and the exhaust unit (46) are controlled so that the desired composition (for example, oxygen concentration 5%, carbon dioxide concentration 5%) is obtained.

In addition, the control unit (55) controls the operation of the gas concentration measuring on-off valve (82) in response to a command from the user or at regular intervals so that the oxygen of the nitrogen-enriched air generated in the gas supply device (30) is generated. It is configured to perform an air supply measuring operation for measuring the concentration.

In the present embodiment, the control unit (55) includes a microcomputer that controls each element of the CA device (60) as disclosed in the present application, and a memory or a hard disk in which an executable control program is stored. There is. The control unit (55) is an example of the control unit of the CA device (60), and the detailed structure and algorithm of the control unit (55) depend on what hardware to execute the function according to the present invention. It may be a combination with software.

The control section (55) controls the operation of the air pump (31) to perform the first operation, the second operation, and the pressure equalizing operation. The control section (55) also controls the outside air introduction operation.

-Driving operation-
<Operation of refrigerant circuit>
In the present embodiment, the unit controller (100) shown in FIG. 3 executes a cooling operation for cooling the air inside the container (11).

In the cooling operation, the operation of the compressor (21), the expansion valve (23), the outdoor fan (25) and the internal fan (26) is controlled by the unit controller (100) based on the measurement result of the temperature sensor (not shown). The temperature of the inside air is controlled to reach a desired target temperature. At this time, the refrigerant circulates in the refrigerant circuit (20) to perform a vapor compression refrigeration cycle. Then, the inside air of the container (11) guided to the inside storage space (S2) by the inside fan (26) flows inside the evaporator (24) when passing through the evaporator (24). It is cooled by the refrigerant. The inside air cooled in the evaporator (24) passes through the underfloor flow path (19a) and is blown again into the inside of the container (11) from the outlet (18b). As a result, the air inside the container (11) is cooled.

<Concentration control operation>
Further, in the present embodiment, the control unit (55) shown in FIG. 4 causes the CA device (60) to change the composition (oxygen concentration and carbon dioxide concentration) of the air inside the container (11) to a desired composition (for example, Oxygen concentration is 5% and carbon dioxide concentration is 5%). In the concentration adjustment operation, the control unit (55) adjusts the composition of the air inside the container (11) to a desired composition based on the measurement results of the oxygen sensor (51) and the carbon dioxide sensor (52). The operations of the gas supply device (30) and the exhaust unit (46) are controlled.

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

(Adjustment of oxygen concentration)
The control unit (55) generates nitrogen-concentrated air by a gas generation operation when the oxygen concentration of the inside air measured by the oxygen sensor (51) is higher than 8%, and the nitrogen-concentrated air is stored in the container (11). The above-described gas supply operation of supplying the gas into the storage compartment is performed.

Specifically, the control unit (55) switches the first directional control valve (32) and the second directional control valve (33) to sandwich the pressure equalizing operation (see FIG. 6) and then perform the first operation (FIG. 4). And the second operation (see FIG. 5) are alternately repeated to generate nitrogen-concentrated air whose nitrogen concentration is higher than that of the outside air and whose oxygen concentration is lower than that of the outside air (the above gas generation operation). In this embodiment, the operation time of the first operation and the second operation is set to 14.5 seconds, and the operation time of the pressure equalizing operation is set to 1.5 seconds. The control section (55) controls the exhaust on-off valve (72) to be in a closed state and the supply side on-off valve (73) to be in an open state so that the nitrogen-concentrated air generated by the gas generating operation is stored in the container (11). ) The gas supply operation for supplying the gas into the chamber is executed. In the present embodiment, the average nitrogen concentration in the inside of the container (11) (the average value of the nitrogen concentration of the nitrogen-concentrated air supplied to the inside in each of the first operation and the second operation) is 92%. The nitrogen-concentrated air having an average oxygen concentration of 8% (the average value of the oxygen concentration of the nitrogen-concentrated air supplied into the refrigerator in each of the first operation and the second operation) is supplied.

Further, the control unit (55) controls the exhaust valve (46b) of the exhaust unit (46) to an open state to perform the exhaust operation, and supplies the nitrogen-concentrated air to the inside of the container (11) by the gas supply operation. The air in the refrigerator is exhausted by the amount outside the refrigerator.

In the concentration adjusting operation, the air in the cold storage is replaced with the nitrogen-enriched air by the gas supply operation and the exhaust operation as described above, and the oxygen concentration of the cold air in the cold storage is reduced.

When the oxygen concentration of the air inside the container (11) drops to 8%, the control unit (55) stops the operation of the gas supply device (30) to stop the gas supply operation and the exhaust valve (46b). To close the exhaust operation.

When the gas supply operation and the gas exhaust operation are stopped, the air in the container (11) is not exchanged at all, while the plants (15) breathe, so the oxygen in the air in the container (11) is changed. The concentration decreases and the carbon dioxide concentration increases. As a result, the oxygen concentration of the internal air reaches 5% of the target oxygen concentration.

If the oxygen concentration in the air inside the container (11) drops below 5% due to breathing, the gas supply device (30) is restarted and nitrogen-enriched air with an average oxygen concentration of 8% is added to the container. The gas supply operation for supplying the inside of the chamber of (11) and the exhaust valve (46b) of the exhaust section (46) were controlled to the open state to supply the nitrogen enriched air into the inside of the container (11) by the gas supplying operation. Exhaust operation is performed to discharge the air in the refrigerator to the outside by the amount. By such a gas supply operation and an exhaust operation, the inside air is replaced with nitrogen-enriched air having a higher oxygen concentration than the inside air (for example, an average oxygen concentration of 8%). The oxygen concentration of the internal air rises.

The control unit (55), when the oxygen concentration of the indoor air reaches a value (5.5%) higher than the target oxygen concentration (5%) by a predetermined concentration (for example, 0.5%), the gas supply device ( The operation of 30) is stopped to stop the gas supply operation, and the exhaust valve (46b) is closed to stop the exhaust operation.

Further, the oxygen concentration of the inside air is adjusted by opening the bypass opening/closing valve (48) and sucking the outside air sucked by the air pump (31), instead of the gas supply operation, into the first and second adsorption cylinders (34, 35). ) Can be bypassed without passing, and the operation can be performed by the outside air introduction operation of directly supplying the inside of the container (11). According to the outside air introduction operation and the exhaust operation, the inside air is replaced with the outside air having an oxygen concentration of 21%, so that the oxygen concentration of the inside air of the container (11) increases. At this time, the outside air passes through the cooling section (40a), so that the temperature rise of the inside air can be suppressed.

In this embodiment, in order to reduce the oxygen concentration of the air inside the container (11) from 8% to 5%, the gas supply operation and the exhaust operation are stopped and the respiration of the plant (15) is used. Is decreasing. However, the method of lowering the oxygen concentration of the air inside the container (11) from 8% to 5% is not limited to this. For example, in the initial stage of the desorption operation (immediately after the start of each operation of the first operation and the second operation), the gas discharging operation for discharging the generated nitrogen-enriched air to the outside of the refrigerator is performed, and the gas is generated at other timings. A gas supply operation for supplying nitrogen-enriched air to the interior may be performed. At the beginning of the desorption operation, outside air remains in the adsorption column, piping, etc., so nitrogen-enriched air with a relatively high oxygen concentration is generated, and at the end of the desorption operation, the pressure in the adsorption column is higher than the initial pressure. Due to the decrease, a large amount of nitrogen component is desorbed, and nitrogen-enriched air having a relatively low oxygen concentration is generated. Therefore, by performing the gas discharge operation before such a gas supply operation, the nitrogen-enriched air having a relatively high oxygen concentration immediately after the start of the desorption operation is not supplied to the inside of the container (11) and the container (11) Only the nitrogen-enriched air having a relatively low oxygen concentration (for example, the average nitrogen concentration is 95% and the average oxygen concentration is 5%) is supplied to the inside of the chamber. The oxygen concentration of the air inside the container (11) may be reduced from 8% to 5% by such a gas discharging operation, a gas supplying operation, and an exhausting operation.

(Adjustment of carbon dioxide concentration)
When the carbon dioxide concentration of the inside air measured by the carbon dioxide sensor (52) is higher than 5%, the control unit (55) operates the gas supply device (30) to perform the gas supply operation and exhaust gas. Open the valve (46b) to perform the exhaust operation. By such a gas supply operation and an exhaust operation, the inside air is replaced with the nitrogen-enriched air having a carbon dioxide concentration of 0.03%, so that the carbon dioxide concentration of the inside air of the container (11) is lowered.

The control unit (55) supplies gas when the carbon dioxide concentration of the indoor air reaches a value (4.5%) lower than the target carbon dioxide concentration (5%) by a predetermined concentration (for example, 0.5%). The operation of the device (30) is stopped to stop the gas supply operation, and the exhaust valve (46b) is closed to stop the exhaust operation.

Note that the carbon dioxide concentration of the indoor air may be adjusted by opening the bypass opening/closing valve (48) instead of performing the gas supply operation and performing the outside air introduction operation. As described above, according to the outside air introduction operation and the exhaust operation, the inside air is replaced with the outside air having a carbon dioxide concentration of 0.03%, so that the carbon dioxide concentration of the inside air of the container (11) is reduced.

[Air supply measurement operation]
In addition, the control unit (55) performs an air supply measurement operation of measuring the oxygen concentration of the nitrogen-enriched air generated in the gas supply device (30) 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 concentration adjustment operation and the trial operation described above.

The control section (55) controls the gas concentration measuring on-off valve (82) to be in the open state and the supply side on-off valve (73) to be in the closed state during the gas supply operation. As a result, all the nitrogen-enriched air flowing through the supply passageway (44) flows into the branch pipe (81). The nitrogen-enriched air that has flowed into the branch pipe (81) flows into the oxygen sensor (51), and the oxygen concentration is measured.

In this way, by measuring the oxygen concentration of the nitrogen-enriched air generated in the gas supply device (30), the composition (oxygen concentration, nitrogen concentration) of the nitrogen-enriched air generated in the gas supply device (30) is desired. You can check whether or not it is.

-Effect of embodiment-
As described above, according to the present embodiment, by switching the flow state of air in the air circuit (3), not only the nitrogen-enriched air generated in the air circuit (3) but also the air in the air circuit (3) Air having the same composition as the outside air can be pushed into the inside of the container (11) by the pressing force of the first pump mechanism (31a). Therefore, even when the pressure inside the container (11) is higher than the pressure of the outside air, air having the same composition as the outside air can be smoothly supplied into the inside of the container (11). Therefore, in the container refrigeration system (10) having the gas supply device (30), the composition (oxygen concentration, carbon dioxide concentration) of the inside air can be quickly and accurately adjusted to a desired composition.

Further, during the outside air introduction operation, when the outside air supplied to the inside of the refrigerator passes through the cooling section (40a) outside the refrigerator, it is effectively cooled by the air flowing through the condenser (22). It is possible to prevent the temperature of the air from rising and prevent early damage to the plant.

<<Other Embodiments>>
The above embodiments may have the following configurations.

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

Further, in each of the above-described embodiments, one adsorption cylinder is used for each of the first adsorption section and the second adsorption section to adsorb and desorb nitrogen. The number is not limited to one. For example, each suction unit may be configured by three suction cylinders, and a total of six suction cylinders may be used.

Further, in each of the above-described embodiments, an example in which the CA device (60) according to the present invention is applied to the container refrigerating device (10) provided in the container (11) for marine transportation has been described. The use of the device (60) is not limited to this. The CA device (60) according to the present invention can be used for adjusting the composition of the air in a container such as a container for land transportation, a container for freezing and refrigerating, a room temperature warehouse, etc., in addition to a container for sea transportation.

Note that the above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its application.

INDUSTRIAL APPLICABILITY As described above, the present invention is useful for a technique of supplying not only nitrogen-concentrated air but also air having the same composition as the outside air into the chamber in a gas supply device that pumps nitrogen-concentrated air into the container. is there.

1 Container refrigeration equipment
11 containers
12 casing
20 Refrigerant circuit
30 gas supply device
31 Air pump
31a First pump mechanism (pressurizing pump mechanism)
31b Second pump mechanism (decompression pump mechanism)
34 1st adsorption cylinder
35 Second adsorption cylinder
40 Outside air introduction passage
40a cooling unit
42 Pressurized passage
44 Supply passage
46 Exhaust section
47 Bypass passage
48 Bypass valve
60 CA device (air conditioner in the refrigerator)

Claims (3)

It is installed in a container (11) that stores the breathing plant (15),
Two adsorption cylinders (34, 35) each containing an adsorbent that adsorbs nitrogen components in the air,
By supplying pressurized air obtained by pressurizing the outside air to one of the adsorption cylinders (34, 35), the adsorption cylinders (34, 35) are pressurized, and nitrogen in the compressed air is adsorbed in the adsorption cylinders (34, 35). A pressure pump mechanism (31a) for adsorbing components to the adsorbent, and depressurizing the adsorption cylinders (35, 34) by sucking air from the other adsorption cylinder (35, 34). An air pump (31) having a decompression pump mechanism (31b) for performing a desorption operation for desorbing the nitrogen component adsorbed on the adsorbent in the adsorption column (35, 34),
A pressure passage (42) connected to the discharge port of the pressure pump mechanism (31a) and the suction cylinders (34, 35);
The decompression pump mechanism (31b) so that the adsorption operation and the desorption operation are alternately performed in the adsorption column (34, 35) and the nitrogen-enriched air generated by the desorption operation is supplied to the inside of the container (11). A supply passageway (44) connected to
A gas supply device comprising:
A bypass passage (47) connected to the outlet of the pressure pump mechanism (31a) in the pressure passage (42) and the outlet of the pressure reduction pump mechanism (31b) in the supply passage (44), and the bypass passage. A bypass opening/closing valve (48) provided in (47), and an outside air introduction passage (40) for supplying the pressurized air that has passed through the pressure pump mechanism (31a) to the interior. Characteristic gas supply device. In claim 1,
While including a unit case (36) for accommodating the suction cylinders (34, 35) and the air pump (31),
A gas supply device characterized in that a cooling section (40a) passing through a space outside the unit case (36) is provided in a part of the outside air introduction passageway (40). It is attached to the container (11) that holds the plants that breathe,
A refrigerant circuit (20) for performing a refrigeration cycle to cool the air inside the container,
The container (11) includes a gas supply device (30) for supplying gas to the inside of the container (11), and an exhaust unit (46) for discharging air inside the container (11) to the outside of the container (11). ) Is a refrigeration system for a container, comprising:
The container gas refrigeration apparatus (30) comprises the gas gas supply apparatus according to claim 1 or 2.

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