Estimation device and refrigeration cycle device

Abstract

The present invention provides an estimation device capable of estimating the flow rate of gases entering the interior space of a container. [Solution] The estimation device comprises a supply unit (231a, 231b) that supplies gas to the internal space (5) of the container (1), a first pressure detection unit (170) that detects the internal pressure, which is the pressure in the internal space (5), and a control unit (110) that determines an airtightness index, which is an indicator of the airtightness of the internal space (5). The control unit (110) estimates a first flow rate, which is the flow rate of gas supplied to the internal space (5), based on the internal pressure during operation of the supply unit (231a, 231b) and the airtightness index.

Description

Technical Field

[0001] The present disclosure relates to an estimation device and a refrigeration cycle device.

Background Art

[0002] Patent Document 1 discloses a transport container. The transport container has a transport refrigeration device. The transport refrigeration device cools the air in the storage space of the container. The transport container has an air composition adjustment device that adjusts the composition of the air in the storage space. The air composition adjustment device adjusts the oxygen concentration and carbon dioxide concentration of the air in the storage space.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Gases such as outside air or a processed gas obtained by processing outside air are supplied into the storage space of the container according to the goods stored in the container. By supplying a gas at a preset flow rate into the storage space, the storage space is maintained in a predetermined environment. Therefore, it is preferable to measure the actual flow rate of the gas flowing into the storage space, but providing a sensor for measuring the gas flow rate increases the cost.

[0005] The present disclosure provides an estimation device that can estimate the flow rate of a gas flowing into the storage space of a container.

Means for Solving the Problems

[0006] A first aspect is a supply unit (2*31a, 2*31b) that supplies a gas to the storage space (5) of a container (1), and [[ID=5*]]a first pressure detection unit (17*) that detects the internal pressure, which is the pressure of the storage space (5). The system includes a control unit (110) that determines an airtightness index, which is an indicator of the airtightness of the internal space (5) of the storage area, The control unit (110) estimates a first flow rate, which is the flow rate of the gas supplied to the internal space (5), based on the internal pressure and airtightness index during operation of the supply units (231a, 231b). It is an estimation device.

[0007] In the first embodiment, the flow rate of gas supplied to the internal space (5) can be estimated, eliminating the need for measuring sensors. Therefore, it is possible to suppress the increase in the number of parts and the resulting cost increase due to the installation of sensors.

[0008] A second aspect is, in the first aspect, The supply units (231a, 231b) are provided in the air composition adjustment device (100) which adjusts the air composition in the internal space (5) of the chamber. The supply unit (231a, 231b) includes a first transport unit (231a) that transports outside air to the internal space (5), and a second transport unit (231b) that transports a gas to be processed, which has a different composition from the outside air, to the internal space (5). The first flow rate is the flow rate of the gas to be treated that is transported to the internal space (5) by the second transport unit (231b).

[0009] In the second embodiment, the flow rate of the gas to be treated, which is transported to the chamber space (5) by the pressure-reducing pump (231b) while the air composition adjustment device (100) is in operation, can be estimated.

[0010] A third aspect is, in the second aspect, The control unit (110) estimates the first flow rate based on the airtightness index when outside air is supplied to the internal space (5) by the first transport unit (231a).

[0011] In the third embodiment, the first flow rate of the gas transported into the internal space (5) by the second transport unit (231b) can be estimated using the airtightness index when outside air is introduced into the internal space (5) by the first transport unit (231a).

[0012] A fourth aspect is a second or third aspect, The air composition adjustment device (100) performs a first mode in which outside air is introduced into the internal space (5) without changing its composition, and a second mode in which the gas to be treated is introduced into the internal space (5). The control unit (110) estimates the first flow rate in the process of sequentially executing the first mode and the second mode.

[0013] In the fourth embodiment, in operation in which the air composition adjustment device (100) sequentially performs a first mode and a second mode, the airtightness index of the interior space (5) can be determined by the execution of the first mode, and the first flow rate of the gas can be estimated in the subsequent second mode using this airtightness index.

[0014] The fifth aspect is one of the first to fourth aspects, The control unit (110) evaluates any abnormalities in the supply units (231a, 231b) based on the estimated first flow rate.

[0015] If the estimated value of the first flow rate differs from the preset flow rate value, it can be determined that the supply unit (231a, 231b) is not properly transporting the gas into the storage space (5). In other words, it can be confirmed that there is a problem with the supply unit (231a, 231b). In this way, there is no need to perform regular maintenance on the supply unit (231a, 231b), and maintenance costs can be reduced because parts replacement or repairs only need to be done when a problem is confirmed with the supply unit (231a, 231b).

[0016] The sixth aspect is one of the first to fifth aspects, The first pressure detection unit (170) includes a differential pressure sensor that detects the differential pressure between the outside air and the inside air of the storage unit.

[0017] In the sixth embodiment, the pressure of the internal space (5) can be detected by differential pressure when the pressure of the air outside the chamber is set to standard atmospheric pressure.

[0018] The seventh aspect is as follows in any one of the first to fourth aspects: It further includes a second pressure detection unit (180) for detecting the pressure of the outside air of the warehouse, Based on the detection values of the first pressure detection unit (170) and the second pressure detection unit (180), the control unit (110) obtains the airtightness index.

[0019] In the seventh aspect, the pressure change (leakage amount) of the internal pressure of the internal space (5) of the warehouse is affected by the pressure of the outside air of the warehouse. Therefore, by using the detected value of the pressure of the outside air of the warehouse, the internal pressure of the internal space (5) of the warehouse can be obtained more accurately.

[0020] The eighth aspect is a refrigeration cycle device including any one of the estimation devices (E) of the first to seventh aspects and a refrigerant circuit (11) for cooling the internal space (5) of the warehouse.

[0021] In the eighth aspect, a refrigeration cycle device capable of estimating the gas flow rate into the internal space (5) can be provided. In particular, when the cargo in the container (1) is fresh food, in addition to temperature management of the internal space (5), management of the air composition is required. Therefore, estimation of the gas flow rate into the internal space (5) is useful for transporting such cargo.

Brief Description of Drawings

[0022] [Figure 1] FIG. 1 is a schematic perspective view of a refrigeration device for transportation according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a transportation container equipped with a refrigeration device for transportation according to an embodiment. [Figure 3] FIG. 3 is a piping system diagram showing a refrigerant circuit of a refrigeration device for transportation according to an embodiment. [Figure 4] FIG. 4 is a schematic front view of a ventilation device. FIG. 4(A) shows a state where the opening / closing lid is in the closed position, FIG. 4(B) shows a state where the opening / closing lid is in the intermediate position, and FIG. 4(C) shows a state where the opening / closing lid is in the fully open position. [Figure 5]Figure 5 is a piping diagram showing the configuration of the air composition adjustment device according to the embodiment. [Figure 6] Figure 6 is a diagram corresponding to Figure 5, showing the air composition adjustment device that performs the first operation of the gas supply operation. [Figure 7] Figure 7 is a diagram corresponding to Figure 5, showing the air composition adjustment device that performs the second operation of the gas supply operation. [Figure 8] Figure 8 corresponds to Figure 5, which shows an air composition adjustment device that performs outside air intake. [Figure 9] Figure 9 is a block diagram showing the configuration of the control unit included in the air composition adjustment device of the embodiment. [Figure 10] Figure 10 is a table showing the timing of operation in the 8% oxygen concentration mode. [Figure 11] Figure 11 is a table showing the timing of operation in the 5% oxygen concentration mode. [Figure 12] Figure 12 shows a flowchart, timing chart, and formulas to explain the first airtightness measurement mode. [Figure 13] Figure 13 shows a flowchart, timing chart, and formulas to explain the second airtightness measurement mode. [Figure 14] Figure 14 shows a flowchart, timing chart, and formulas to explain the third airtightness measurement mode. [Figure 15] Figure 15 is a flowchart illustrating the abnormality detection operation of the air pump. [Figure 16] Figure 16 is a diagram corresponding to Figure 2 of the transport container in Modification Example 1. [Figure 17] Figure 17 is a diagram corresponding to Figure 2 of the transport container in Modification Example 1. [Modes for carrying out the invention]

[0023] The embodiments of this disclosure will be described below with reference to the drawings. In the following description, the terms "front," "back," "up," "down," "right," and "left" refer to the directions indicated by the arrows in Figure 1.

[0024] (1) Overview This disclosure relates to a transport container (1). This transport container (1) is a reefer container capable of controlling the internal temperature. This transport container (1) is used for transporting perishable goods (e.g., fruits, vegetables, flowers, etc.) that respire by taking in oxygen (O2) from the air and releasing carbon dioxide (CO2).

[0025] As shown in Figures 1 and 2, the transport container (1) comprises a container body (2) and a transport refrigeration unit (10). The transport refrigeration unit (10) is attached to the container body (2). The transport container (1) is used for maritime transport. The transport container (1) is transported by a maritime transport vehicle such as a ship.

[0026] The container body (2) is a storage unit for the fresh produce mentioned above.

[0027] The container body (2) is formed in the shape of a hollow box. The container body (2) is formed in a horizontal shape. An opening is formed at one end of the container body (2) in the longitudinal direction. The opening of the container body (2) is closed by a transport refrigeration device (10). Inside the container body (2), an interior space (5) is formed for storing perishable goods.

[0028] A floor plate (3) for loading cargo is placed at the bottom of the interior space (5). Between this floor plate (3) and the bottom plate of the container body (2), an underfloor passage (4) is formed for the air blown out by the transport refrigeration unit (10) to flow. The underfloor passage (4) is a passage that extends along the bottom plate of the container body (2) in the longitudinal direction of the container body (2). One end of the underfloor passage (4) is connected to the outlet (27) of the transport refrigeration unit (10), and the other end communicates with the space above the floor plate (3) (i.e., the space where the cargo is stored).

[0029] (2) Basic configuration of transport refrigeration equipment The transport refrigeration device (10) comprises a casing (20), a refrigerant circuit (11) for performing the refrigeration cycle, an external fan (34), and an internal fan (35) as a refrigeration cycle device.

[0030] (2-1) Casing The casing (20) comprises an outer wall section (21), an inner wall section (22), a back panel (24), and a partition panel (25). As will be described later, the casing (20) is equipped with a refrigerant circuit (11), an outer fan (34), and an inner fan (35).

[0031] The outer wall portion (21) is a plate-shaped member positioned to cover the open end of the container body (2). The lower part of the outer wall portion (21) bulges inward into the container body (2). The inner wall portion (22) is a plate-shaped member that follows the shape of the outer wall portion (21). The inner wall portion (22) is positioned to cover the inner surface of the outer wall portion (21) of the container body (2). The space between the outer wall portion (21) and the inner wall portion (22) is filled with insulation material (23).

[0032] The casing (20) has a shape in which its lower part is recessed inward into the container body (2). The lower part of the casing (20) forms an external equipment room (28) that communicates with the external space of the transport container (1). An external fan (34) is located in this external equipment room (28).

[0033] The back panel (24) is a generally rectangular, flat member. The back panel (24) is positioned inside the container body (2) relative to the interior wall (22), and forms an internal air passage (29) between the back panel (24) and the interior wall (22). The upper end of this internal air passage (29) constitutes the intake port (26) of the casing (20), and the lower end constitutes the outlet port (27) of the casing (20).

[0034] The partition plate (25) is a plate-shaped member positioned to divide the internal air passage (29) vertically. The partition plate (25) is positioned above the internal air passage (29). This partition plate (25) divides the internal air passage (29) into a primary passage (29a) above the partition plate (25) and a secondary passage (29b) below the partition plate (25). The primary passage (29a) communicates with the internal space (5) via an intake port (26). The secondary passage (29b) communicates with the underfloor passage (4) via an outlet port (27). An internal fan (35) is attached to the partition plate (25). The internal fan (35) is positioned to draw in air from the primary passage (29a) and blow it out into the secondary passage (29b).

[0035] (2-2) Refrigerant circuit As shown in Figure 3, the refrigerant circuit (11) is a closed circuit formed by connecting the compressor (12), the external heat exchanger (13), the expansion valve (14), and the internal heat exchanger (15) with piping. When the compressor (12) is operated, the refrigerant circulates through the refrigerant circuit (11), and a vapor compression refrigeration cycle is performed. As shown in Figure 2, the external heat exchanger (13) is located in the external equipment room (28), and the internal heat exchanger (15) is located in the secondary flow path (29b) of the internal air flow path (29). The compressor (12) is located in the external equipment room (28).

[0036] (2-3) Operation of transport refrigeration equipment The transport refrigeration unit (10) performs a cooling operation to cool the air inside the transport container (1).

[0037] During cooling operation, the compressor (12) of the refrigerant circuit (11) operates, and the refrigerant circulates in the refrigerant circuit (11), performing a vapor compression refrigeration cycle. In the refrigerant circuit (11), the refrigerant discharged from the compressor (12) passes sequentially through the external heat exchanger (13), the expansion valve (14), and the internal heat exchanger (15), and is then drawn into the compressor (12) and compressed.

[0038] During cooling operation, the external fan (34) and the internal fan (35) operate. When the external fan (34) operates, outside air from the outside of the transport container (1) is drawn into the external equipment room (28) and passes through the external heat exchanger (13). In the external heat exchanger (13), the refrigerant releases heat to the outside air and condenses. When the internal fan (35) operates, the internal air from the internal space (5) of the transport container (1) is drawn into the internal air passage (29) and passes through the internal heat exchanger (15). In the internal heat exchanger (15), the refrigerant absorbs heat from the internal air and evaporates.

[0039] Let's explain the airflow inside the storage unit. The air present in the storage unit space (5) flows through the intake port (26) into the primary flow path (29a) of the storage unit airflow path (29), and is blown out into the secondary flow path (29b) by the storage unit fan (35). The air that flows into the secondary flow path (29b) is cooled as it passes through the storage unit heat exchanger (15), and is then blown out from the outlet (27) into the underfloor flow path (4), and flows back into the storage unit space (5) through the underfloor flow path (4).

[0040] In the internal air passage (29), the primary passage (29a) is located on the intake side of the internal fan (35), and the secondary passage (29b) is located on the outlet side of the internal fan (35). Therefore, when the internal fan (35) is operating, the air pressure in the secondary passage (29b) is slightly higher than the air pressure in the primary passage (29a).

[0041] (3) Ventilation system The transport refrigeration unit (10) is equipped with a ventilation unit (40). The ventilation unit (40) ventilates the interior space (5) of the container body (2). The ventilation unit (40) has an air supply function that supplies outside air to the interior space (5) and an exhaust function that discharges the interior air to the outside space (6).

[0042] (3-1) Configuration of the ventilation system As shown in Figure 1, the ventilation device (40) is located in the upper left part of the casing (20) of the transport refrigeration device (10). As shown in Figure 2, the ventilation device (40) is installed in a ventilation opening (38) formed in the casing (20). The ventilation opening (38) penetrates the casing (20) in the front-to-back direction.

[0043] As shown in Figure 2, an air supply passage (41) and an exhaust passage (42) are formed inside the ventilation device (40). The air supply passage (41) and the exhaust passage (42) connect the interior space (5) and the exterior space (6).

[0044] Specifically, the air supply passage (41) connects the primary air passage (29a) of the internal air passage (29) to the external space (6). The end of the air supply passage (41) on the external space (6) side is the air supply port (41a). The air supply port (41a) is an air inlet that connects the external space (6) to the inside of the container body (2). The exhaust passage (42) connects the secondary air passage (29b) of the internal air passage (29) to the external space (6). The end of the exhaust passage (42) on the external space (6) side is the exhaust port (42a). The air supply port (41a) and the exhaust port (42a) are somewhat elongated openings that extend in the circumferential direction.

[0045] The ventilation device (40) includes an opening / closing cover (45). The opening / closing cover (45) is a disc-shaped member. The opening / closing cover (45) is provided to cover the air supply port (41a) and the exhaust port (42a). The opening / closing cover (45) is driven by a motor (not shown) and is rotatable around its central axis.

[0046] As shown in Figure 4, the opening / closing lid (45) has an air intake opening (46) and an exhaust opening (47). Each of the air intake opening (46) and the exhaust opening (47) penetrates the opening / closing lid (45) in the thickness direction. The shape of the air intake opening (46) is the same as the shape of the air intake port (41a). The shape of the exhaust opening (47) is the same as the shape of the exhaust port (42a). In the opening / closing lid (45), the air intake opening (46) and the exhaust opening (47) are formed in such a position that when the entire air intake opening (46) overlaps with the air intake port (41a), the entire exhaust opening (47) overlaps with the exhaust port (42a).

[0047] (3-2) Operation of the ventilation system The ventilation device (40) is configured to adjust the flow rate of outside air supplied to the interior space (5) (supply air flow rate) and the flow rate of inside air discharged from the interior space (5) (exhaust air flow rate) by rotating the opening and closing lid (45).

[0048] Specifically, when the opening / closing lid (45) is rotated, the area of ​​the portion of the air supply port (41a) that overlaps with the air supply opening (46) and the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) change. Outside air flows into the air supply passage (41) through the portion of the air supply port (41a) that overlaps with the air supply opening (46), and then flows into the interior space (5). Inside air flowing through the exhaust passage (42) flows out into the exterior space (6) through the portion of the exhaust port (42a) that overlaps with the exhaust opening (47).

[0049] Increasing the area of ​​the portion of the air supply port (41a) that overlaps with the air supply opening (46) increases the air supply flow rate, while decreasing the area of ​​that portion decreases the air supply flow rate. Increasing the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) increases the exhaust flow rate, while decreasing the area of ​​that portion decreases the exhaust flow rate.

[0050] When the opening / closing cover (45) is in the position shown in Figure 4(A), the entire air supply port (41a) is covered by the opening / closing cover (45), and the entire exhaust port (42a) is also covered by the opening / closing cover (45). As a result, the area of ​​the portion of the air supply port (41a) that overlaps with the air supply opening (46) and the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) become zero. In other words, the air supply passage (41) and the exhaust passage (42) become completely closed. Therefore, in this state, both the air supply flow rate and the exhaust flow rate become zero.

[0051] When the opening / closing cover (45) is in the position shown in Figure 4(C), the entire air intake port (41a) overlaps with the air intake opening (46), and the entire exhaust port (42a) overlaps with the exhaust opening (47). Therefore, the area of ​​the portion of the air intake port (41a) that overlaps with the air intake opening (46) (the dotted portion in Figure 4(C)) and the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) (the dotted portion in Figure 4(C)) are both maximized. In other words, the air intake passage (41) and the exhaust passage (42) are fully open. Consequently, in this state, both the air intake flow rate and the exhaust flow rate reach their maximum flow rates.

[0052] When the opening / closing cover (45) is in the position shown in Figure 4(B), a portion of the air intake port (41a) overlaps with the air intake opening (46), and a portion of the exhaust port (42a) overlaps with the exhaust opening (47). As a result, the area of ​​the portion of the air intake port (41a) that overlaps with the air intake opening (46) (the dotted portion in Figure 4(B)) and the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) (the dotted portion in Figure 4(B)) are both intermediate areas smaller than the maximum. Therefore, in this state, both the air intake flow rate and the exhaust flow rate are intermediate flow rates that are greater than zero and less than the maximum flow rate.

[0053] (4) Air composition adjustment device The air composition adjustment device (100) processes the ambient air outside the container to generate a treated gas with a different composition from the outside air. The air composition adjustment device (100) supplies the generated treated gas to the interior space (5) of the container body (2).

[0054] (4-1) Basic configuration of an air composition control device The air composition control device (100) is installed in the transport refrigeration unit (10) to perform so-called CA (Controlled Atmosphere) transport. The air composition control device (100) adjusts the air composition in the interior space (5) of the transport container (1).

[0055] As shown in Figure 5, the air composition adjustment device (100) comprises a filter unit (220), a main unit (200), a gas supply pipe (275), a gas discharge pipe (276), a sensor unit (160), and a ventilation exhaust pipe (150). The air composition adjustment device (100) is a so-called PSA (Pressure Swing Adsorption) type gas separation device.

[0056] The air composition adjustment device (100) generates the gas to be treated by processing the outside air, which is the ambient air. Specifically, the air composition adjustment device (100) separates the outside air into a nitrogen-enriched gas with a higher nitrogen concentration and a lower oxygen concentration than the outside air, and an oxygen-enriched gas with a lower nitrogen concentration and a higher oxygen concentration than the outside air. The air composition adjustment device (100) supplies the gaseous outside air and the gas to be treated into the interior space (5).

[0057] (4-2) Filter unit, outside air pipe The filter unit (220) is a box-shaped component. The filter unit (220) is installed in the external equipment room (28) of the transport refrigeration unit (10). The filter unit (220) includes an air filter (221). The air filter (221) is a filter for capturing dust, salt, and other particles contained in the outside air. The air filter (221) in this embodiment is a membrane filter that has both breathability and waterproofing properties.

[0058] The filter unit (220) is connected to the main unit (200) via an outside air pipe (241). One end of the outside air pipe (241) is connected to the filter unit (220). The other end of the outside air pipe (241) is connected to an air pump (231), which will be described later. The outside air pipe (241) guides the outside air (atmosphere) that has passed through the air filter (221) to the air pump (231).

[0059] (4-3) Main Unit The main unit (200) is installed in the external equipment room (28) of the transport refrigeration system (10). The main unit (200) comprises an air pump (231), a first suction cylinder (234), a second suction cylinder (235), a first switching valve (232), a second switching valve (233), and a unit case (201) that houses these components. The unit case (201) houses an inlet pipe (242), a suction pipe (243), a first gas pipe (244), and a second gas pipe (245).

[0060] (4-4) Air pump An air pump (231) is an example of a supply unit that supplies gas to the internal space (5) of a transport container (1). The air pump (231) comprises a pressurizing pump (231a), a depressurizing pump (231b), and a drive motor (231c). The pressurizing pump (231a) and the depressurizing pump (231b) each draw in and discharge air. The pressurizing pump (231a) and the depressurizing pump (231b) are connected to the drive shaft of a single drive motor (231c). In the air pump (231), both the pressurizing pump (231a) and the depressurizing pump (231b) are driven by a single drive motor (231c).

[0061] The other end of the outside air pipe (241) is connected to the intake port of the pressurizing pump (231a). One end of the inlet pipe (242) is connected to the discharge port of the pressurizing pump (231a). The pressurizing pump (231a) supplies the air to be treated, drawn in from the outside air pipe (241), to the first adsorption cylinder (234) and the second adsorption cylinder (235) through the inlet pipe (242).

[0062] A suction tube (243) is connected to the inlet of the pressure reducing pump (231b). A first gas pipe (244) is connected to the discharge port of the pressure reducing pump (231b). The pressure reducing pump (231b) discharges the gas drawn in from the first adsorption cylinder (234) and the second adsorption cylinder (235) through the suction tube (243) into the first gas pipe (244).

[0063] (4-5) Introduction pipe The inlet pipe (242) is a pipe that guides the air to be treated, discharged by the pressurizing pump (231a), to the first adsorption cylinder (234) and the second adsorption cylinder (235). One end of the inlet pipe (242) is connected to the discharge port of the pressurizing pump (231a). The other end of the inlet pipe (242) branches into two branch pipes, one of which is connected to the first switching valve (232), and the other branch pipe is connected to the second switching valve (233).

[0064] (4-6) Suction tube The suction pipe (243) is a pipe that guides the gas flowing out from the first adsorption cylinder (234) and the second adsorption cylinder (235) to the pressure reducing pump (231b). One end of the suction pipe (243) is connected to the suction port of the pressure reducing pump (231b). The other end of the suction pipe (243) branches into two branch pipes, one of which is connected to the first switching valve (232), and the other branch pipe is connected to the second switching valve (233).

[0065] (4-7) First gas pipe The first gas pipe (244) is the piping through which nitrogen-enriched gas discharged from the pressure-reducing pump (231b) flows. One end of the first gas pipe (244) is connected to the discharge port of the pressure-reducing pump (231b). The other end of the first gas pipe (244) is connected to the gas supply pipe (275).

[0066] A check valve (264) is provided in the first gas pipe (244). This check valve (264) allows gas to flow only in the direction from one end to the other of the first gas pipe (244), and blocks gas flow in the reverse direction.

[0067] (4-8) Switching valve The first switching valve (232) and the second switching valve (233) are each switching valves having three ports. The first switching valve (232) and the second switching valve (233) are configured to switch between a first state (shown by a solid line in Figure 3) in which the first port communicates with the second port and is blocked from the third port, and a second state (shown by a dashed line in Figure 3) in which the first port communicates with the third port and is blocked from the second port.

[0068] The first switching valve (232) has its first port connected to one end of the first suction cylinder (234). The first switching valve (232) also has a branch pipe of the inlet pipe (242) connected to its second port and a branch pipe of the suction pipe (243) connected to its third port. The first switching valve (232) switches the first suction cylinder (234) between being connected to the pressurizing pump (231a) and being connected to the depressurizing pump (231b).

[0069] The second switching valve (233) has its first port connected to one end of the second suction cylinder (235). The second switching valve (233) also has a branch pipe of the inlet pipe (242) connected to its second port and a branch pipe of the suction pipe (243) connected to its third port. The second switching valve (233) switches the second suction cylinder (235) between being connected to the pressurizing pump (231a) and being connected to the depressurizing pump (231b).

[0070] (4-9) Adsorption cylinder Each of the first adsorption cylinder (234) and the second adsorption cylinder (235) is a component comprising a cylindrical container with both ends closed and an adsorbent filled in the container. The adsorption cylinders (234, 235) use the adsorbent to separate the air to be treated (in this embodiment, outside air) into oxygen-enriched gas and nitrogen-enriched gas.

[0071] The adsorbent packed into the adsorption cylinders (234, 235) has the property of adsorbing nitrogen and water (water vapor) from the air to be treated under a pressurized state where the pressure is higher than atmospheric pressure, and desorbing nitrogen and water under a reduced pressure state where the pressure is lower than atmospheric pressure. An example of an adsorbent with such properties is a porous zeolite having pores with a diameter smaller than the molecular diameter of a nitrogen molecule (3.0 angstroms) and larger than the molecular diameter of an oxygen molecule (2.8 angstroms).

[0072] The first suction cylinder (234) and the second suction cylinder (235), together with the first switching valve (232) and the second switching valve (233), constitute an air processing unit (95).

[0073] (4-10) Second gas pipe The second gas pipe (245) comprises a main pipe (246), a first branch pipe (247a), and a second branch pipe (247b). The second gas pipe (245) constitutes the first passage through which oxygen-enriched gas flows. The first branch pipe (247a) is a pipe connecting the other end of the first adsorption cylinder (234) to one end of the main pipe (246). The second branch pipe (247b) is a pipe connecting the other end of the second adsorption cylinder (235) to one end of the main pipe (246). Each of the first branch pipe (247a) and the second branch pipe (247b) is provided with one check valve (261). Each check valve (261) allows airflow in the direction of outflow from the corresponding adsorption cylinder (234, 235) and blocks airflow in the reverse direction.

[0074] As described above, the first branch pipe (247a) and the second branch pipe (247b) are connected to one end of the main pipe (246). The other end of the main pipe (246) is connected to the gas discharge pipe (276), which will be described later. The main pipe (246) is provided with an orifice (263) and a check valve (262) in that order from one end to the other. The check valve (262) allows air to flow from one end of the main pipe (246) to the other, and blocks air to flow in the reverse direction.

[0075] (4-11) Purge pipe A purge pipe (250) is connected to each of the first branch pipe (247a) and the second branch pipe (247b) of the second gas pipe (245). One end of the purge pipe (250) is connected to the first branch pipe (247a), and the other end is connected to the second branch pipe (247b). One end of the purge pipe (250) is connected between the first suction cylinder (234) and the check valve (261) in the first branch pipe (247a). The other end of the purge pipe (250) is connected between the second suction cylinder (235) and the check valve (261) in the second branch pipe (247b).

[0076] A purge valve (251) is provided in the purge pipe (250). The purge valve (251) is an on / off valve consisting of a solenoid valve. The purge valve (251) is opened when equalizing the pressure between the first adsorption cylinder (234) and the second adsorption cylinder (235). In addition, one orifice (252) is provided on each side of the purge valve (251) in the purge pipe (250).

[0077] (4-12) Exhaust connection pipe An exhaust connecting pipe (271) is connected to the first gas pipe (244). One end of the exhaust connecting pipe (271) is connected to the first gas pipe (244), and the other end is connected to the second gas pipe (245). One end of the exhaust connecting pipe (271) is connected between the pressure reducing pump (231b) and the check valve (264) in the first gas pipe (244). The other end of the exhaust connecting pipe (271) is connected to one end of the gas discharge pipe (276).

[0078] A gas discharge valve (272) is provided in the exhaust connecting pipe (271). The gas discharge valve (272) is an on / off valve consisting of a solenoid valve. When the gas discharge valve (272) is opened, the nitrogen-enriched gas flowing through the first gas pipe (244) is discharged to the outside of the container body (2).

[0079] (4-13) Gas supply pipe As described above, the first gas pipe (244) is connected to one end of the gas supply pipe (275). The gas supply pipe (275) extends to the outside of the unit case (201). The other end of the gas supply pipe (275) opens downstream of the internal fan (35) in the internal air passage (29) of the transport refrigeration unit (10). The gas supply pipe (275) is a pipe for introducing the gas that flows in from one end into the inside of the container body (2).

[0080] A gas supply valve (273) is provided in the gas supply pipe (275). The gas supply valve (273) is an on / off valve consisting of a solenoid valve.

[0081] (4-14) Gas discharge pipe As described above, one end of the gas discharge pipe (276) is connected to the main pipe (246) of the second gas pipe (245) and the exhaust connecting pipe (271). The gas discharge pipe (276) extends to the outside of the unit case (201). The other end of the gas discharge pipe (276) opens into the external equipment room (28) of the transport container (1). The gas discharge pipe (276) is a pipe for discharging the gas that has flowed in from one end to the outside of the container body (2).

[0082] (4-15) Measurement piping A measuring pipe (281) is connected to the first gas pipe (244). The measuring pipe (281) is the pipe that connects the first gas pipe (244) to the sensor unit (160). One end of the measuring pipe (281) is connected to the downstream side of the check valve (264) in the first gas pipe (244). The other end of the measuring pipe (281) is connected to the sensor unit (160).

[0083] A measuring valve (282) is provided in the measuring piping (281). The measuring valve (282) is a solenoid valve. The measuring valve (282) is opened when air flowing through the first gas pipe (244) is sent to the sensor unit (160).

[0084] (4-16) Bypass pipe A bypass connecting pipe (255) is connected to the inlet pipe (242). The bypass connecting pipe (255) is a pipe that bypasses the first adsorption cylinder (234) and the second adsorption cylinder (235) to supply outside air to the interior space (5) of the transport container (1). One end of the bypass connecting pipe (255) is connected between the branching point of the inlet pipe (242) and the pressurizing pump (231a). The other end of the bypass connecting pipe (255) is connected to one end of the gas supply pipe (275).

[0085] A bypass valve (256) is provided in the bypass connecting pipe (255). The bypass valve (256) is an on / off valve consisting of a solenoid valve. This bypass valve (256) is opened when the outside air discharged by the pressurizing pump (231a) is supplied to the inside space (5) of the storage unit without changing its composition.

[0086] (4-17) Sensor Unit The sensor unit (160) comprises an oxygen sensor (161), a carbon dioxide sensor (162), and a sensor case (163). The sensor unit (160) is a detector that detects the concentration of components in the air inside the chamber. The sensor unit (160) is installed in the secondary flow path (29b) of the internal air flow path (29).

[0087] The oxygen sensor (161) is a zirconia current type sensor that measures the oxygen concentration of a gas mixture such as air. The carbon dioxide sensor (162) is a non-dispersive infrared (NDIR) type sensor that measures the carbon dioxide concentration of a gas mixture such as air. The oxygen sensor (161) and the carbon dioxide sensor (162) are housed in a sensor case (163).

[0088] The sensor case (163) is a box-shaped component. The sensor case (163) is equipped with an air filter (164). The air filter (164) is a membrane filter for capturing dust and other particles contained in the air inside the chamber. The air filter (164) filters the air inside the chamber that flows into the sensor case (163).

[0089] A measuring pipe (281) is connected to the sensor case (163). An outlet pipe (165) is connected to the sensor case (163). The outlet pipe (165) has an inlet end connected to the sensor case (163) and an outlet end that opens upstream of the internal fan (35) in the internal air passage (29). The outlet end of the outlet pipe (165) opens into the primary passage (29a) of the internal air passage (29).

[0090] When the measuring valve (282) is closed, the air inside the storage chamber flows through the sensor case (163). Specifically, the air inside the storage chamber flows through the secondary flow path (29b) of the storage chamber air passage (29), passes through the air filter (164) and flows into the sensor case (163), then passes through the sensor case (163) and flows through the outlet pipe (165) and into the primary flow path (29a) of the storage chamber air passage (29). Therefore, when the measuring valve (282) is closed, the oxygen sensor (161) measures the oxygen concentration of the air inside the storage chamber, and the carbon dioxide sensor (162) measures the carbon dioxide concentration of the air inside the storage chamber.

[0091] On the other hand, when the measuring valve (282) is open, the gas flowing through the measuring pipe (281) flows inside the sensor case (163). Specifically, the gas flowing through the first gas pipe (244) or the bypass connecting pipe (255) flows through the measuring pipe (281) into the sensor case (163), passes through the sensor case (163), flows through the outlet pipe (165), and flows into the primary flow path (29a) of the internal air passage (29). Therefore, when the measuring valve (282) is open, the oxygen sensor (161) measures the oxygen concentration of the gas that flows from the measuring pipe (281) into the sensor case (163), and the carbon dioxide sensor (162) measures the carbon dioxide concentration of the gas that flows from the measuring pipe (281) into the sensor case (163).

[0092] (4-18) Ventilation exhaust pipe The ventilation exhaust pipe (150) is a pipe for discharging the internal air of the transport container (1) to the outside space. The ventilation exhaust pipe (150) penetrates the external wall (21) and internal wall (22) of the transport refrigeration unit (10). A ventilation exhaust valve (151) is provided in the ventilation exhaust pipe (150). The ventilation exhaust valve (151) is an on / off valve consisting of a solenoid valve.

[0093] (4-19) Differential pressure sensor and internal temperature sensor The air composition adjustment device (100) has a differential pressure sensor (170) as a first pressure detection unit. The differential pressure sensor (170) is used to detect the pressure in the internal space (5). The differential pressure sensor (170) detects the differential pressure (ΔP) between the internal pressure (Pi), which is the pressure in the internal space (5), and the external pressure (Po) in the external space (6). As shown in Figures 2 and 5, the differential pressure sensor (170) is placed in the internal space (5). Specifically, the differential pressure sensor (170) is placed in the primary flow path (29a) of the internal air flow path (29). The differential pressure sensor (170) comprises a main body case (171), a sensor unit (172) located inside the main body case (171), an internal communication passage (173) connecting the inside of the main body case (171) to the internal storage space (5), and an external communication passage (174) connecting the inside of the main body case (171) to the external storage space (6).

[0094] The internal communication passage (173) is composed of a communication hole formed in the main body case (171). In this embodiment, the internal communication passage (173) opens toward the primary flow path (29a). More specifically, the internal communication passage (173) opens toward the primary flow path (29a) so as to face away from the intake side of the internal fan (35). This suppresses the influence of the dynamic pressure of the internal air flowing through the internal air passage (29) on the detection value of the differential pressure sensor (170). The external communication passage (174) is formed inside the tube. The tube extends from the main body case (171) to the external space (6). The differential pressure sensor (170) detects the differential pressure ΔP between the internal space (5) and the external space (6).

[0095] The air composition adjustment device (100) has an internal temperature sensor (51). The internal temperature sensor (51) detects the temperature of the air inside the chamber. The internal temperature sensor (51) is positioned in the primary flow path (29a) of the internal air flow path (29).

[0096] (5) Operation of the air composition control device (5-1) Gas supply operation The air composition control device (100) performs a gas supply operation. The gas supply operation generates nitrogen-enriched gas by processing the outside air and supplies this nitrogen-enriched gas to the inside space (5). During the gas supply operation, the ventilation exhaust valve (151) is opened.

[0097] During the gas supply operation, the air composition adjustment device (100) repeatedly performs the first operation and the second operation alternately. The air composition adjustment device (100) repeatedly performs the first operation and the second operation alternately for a predetermined switching time (for example, 14 seconds). As a result, in the air processing unit (95) of the air composition adjustment device (100), the outside air is separated into nitrogen-enriched gas and oxygen-enriched gas.

[0098] (5-1-1) 1st action As shown in Figure 6, in the first operation, the first switching valve (232) is set to the first state and the second switching valve (233) is set to the second state. Also in the first operation, the purge valve (251), the bypass valve (256), and the measuring on / off valve (282) are held in the closed state. In the first operation, the air pump (231) is activated, and an adsorption operation is performed on the first adsorption cylinder (234) and a detachment operation is performed on the second adsorption cylinder (235).

[0099] The pressurizing pump (231a) draws in outside air (atmosphere) from the outside air pipe (241), pressurizes it, and supplies the pressurized outside air to the first adsorption cylinder (234). In the first adsorption cylinder (234), nitrogen and water (water vapor) contained in the supplied outside air are adsorbed by the adsorbent. As a result, oxygen-enriched gas with a lower nitrogen concentration and a higher oxygen concentration than the outside air is produced in the first adsorption cylinder (234). The oxygen-enriched gas flows out from the first adsorption cylinder (234) to the first branch pipe (247a) of the second gas pipe (245), and is then discharged to the outside space (6) through the gas discharge pipe (276).

[0100] Meanwhile, the depressurizing pump (231b) draws gas from the second adsorption cylinder (235). In the second adsorption cylinder (235), the internal pressure decreases, causing nitrogen and water to desorb from the adsorbent. As a result, nitrogen-enriched gas is generated in the second adsorption cylinder (235) with a higher nitrogen concentration and lower oxygen concentration than the outside air. The nitrogen-enriched gas flows from the second adsorption cylinder (235) into the suction pipe (243) and is drawn into the depressurizing pump (231b). The depressurizing pump (231b) pressurizes the drawn-in nitrogen-enriched gas and discharges it into the first gas pipe (244). The nitrogen-enriched gas flowing through the first gas pipe (244) is supplied to the interior space (5) through the gas supply pipe (275).

[0101] (5-1-2)Second operation As shown in Figure 7, in the second operation, the first switching valve (232) is set to the second state and the second switching valve (233) is set to the first state. Also in the second operation, the purge valve (251), the bypass valve (256), and the measuring on / off valve (282) are held in the closed state. Then, in the second operation, the air pump (231) is activated, and a detachment operation targeting the first suction cylinder (234) and an adsorption operation targeting the second suction cylinder (235) are performed.

[0102] The pressurizing pump (231a) draws in outside air (atmosphere) from the outside air pipe (241), pressurizes it, and supplies the pressurized outside air to the second adsorption cylinder (235). In the second adsorption cylinder (235), nitrogen and water (water vapor) contained in the supplied outside air are adsorbed by the adsorbent. As a result, oxygen-enriched gas with a lower nitrogen concentration and a higher oxygen concentration than the outside air is produced in the second adsorption cylinder (235). The oxygen-enriched gas flows out from the second adsorption cylinder (235) to the second branch pipe (247b) of the second gas pipe (245), and is then discharged to the outside space (6) through the gas discharge pipe (276).

[0103] Meanwhile, the depressurizing pump (231b) draws gas from the first adsorption cylinder (234). In the first adsorption cylinder (234), the internal pressure decreases, causing nitrogen and water to desorb from the adsorbent. As a result, nitrogen-enriched gas with a higher nitrogen concentration and lower oxygen concentration than the outside air is generated in the first adsorption cylinder (234). The nitrogen-enriched gas flows from the first adsorption cylinder (234) into the suction pipe (243) and is drawn into the depressurizing pump (231b). The depressurizing pump (231b) pressurizes the drawn-in nitrogen-enriched gas and discharges it into the first gas pipe (244). The nitrogen-enriched gas flowing through the first gas pipe (244) is supplied to the interior space (5) through the gas supply pipe (275). This is an example of a second transport unit (231b) that transports untreated gas with a different composition from the outside air to the interior space (5).

[0104] (5-2) Open air intake operation The air composition adjustment device (100) performs an outside air intake operation. The outside air intake operation is the operation of supplying outside air, which is the atmosphere, to the interior space (5) of the storage facility without changing its composition.

[0105] As shown in Figure 8, during the outside air intake operation, both the first switching valve (232) and the second switching valve (233) are set to the second state. Also, during the outside air intake operation, the gas supply valve (273) and the bypass valve (256) are held in the open state, and the remaining on / off valves (251, 272, 282) are held in the closed state. In addition, during the outside air intake operation, the air pump (231) is activated and the ventilation exhaust valve (151) is opened.

[0106] The pressurizing pump (231a) draws in outside air (atmosphere) from the outside air pipe (241), pressurizes it, and discharges the pressurized outside air to the inlet pipe (242). The outside air discharged from the pressurizing pump (231a) flows sequentially through the inlet pipe (242), the bypass connecting pipe (255), and the gas supply pipe (275), and is supplied to the internal air passage (29). In this way, during the outside air intake operation, air with the same composition as the atmosphere is supplied to the internal space (5) of the transport container (1). Thus, the pressurizing pump (231a) is an example of a first transport unit that transports outside air to the internal space (5).

[0107] The pressure reducing pump (231b) draws gas from both the first adsorption cylinder (234) and the second adsorption cylinder (235), and discharges the drawn-in gas to the first gas pipe (244). The gas discharged by the pressure reducing pump (231b) to the first gas pipe (244) flows into the gas supply pipe (275) and, together with the outside air that flows into the gas supply pipe (275) from the bypass connecting pipe (255), is supplied to the internal air passage (29).

[0108] When the depressurizing pump (231b) draws gas from the first adsorption cylinder (234) and the second adsorption cylinder (235), the pressure in the first adsorption cylinder (234) and the second adsorption cylinder (235) gradually decreases. Then, once the duration of the outside air intake operation exceeds a certain period of time (for example, 45 seconds), the flow rate of gas drawn in by the depressurizing pump (231b) becomes virtually zero.

[0109] (6) Control unit and estimation device The air composition adjustment device (100) has a control unit (110). As shown in Figure 9, the control unit (110) includes a microcomputer (111) mounted on a control board and a memory device (112) that stores software for operating the microcomputer (111). The memory device (112) is a semiconductor memory.

[0110] The control unit (110) controls the components of the air composition adjustment device (100). The control unit (110) receives the measured values ​​from the oxygen sensor (161) and the carbon dioxide sensor (162). The control unit (110) controls the air pump (231), the first switching valve (232), and the second switching valve (233). The control unit (110) also controls the ventilation exhaust valve (151), the purge valve (251), the bypass valve (256), the gas discharge valve (272), the gas supply valve (273), and the measuring on / off valve (282).

[0111] The control unit (110) controls the ventilation device (40). Specifically, the control unit (110) adjusts the opening of the supply air port (41a) and the exhaust air port (42a) by rotating the opening / closing cover (45) of the ventilation device (40). Changing the opening of the supply air port (41a) changes the flow rate of outside air supplied to the interior space (5) through the supply air passage (41). Changing the opening of the exhaust air port (42a) changes the flow rate of inside air discharged to the exterior space (6) through the exhaust passage (42).

[0112] The control unit (110) and estimation device (E) are provided. The estimation device (E) estimates a first flow rate, which is the flow rate of the gas transported into the internal space (5). The gas is the gas to be processed, which is transported into the internal space (5) by the depressurizing pump (231b). The control unit (110) determines an airtightness index, which is an indicator of the airtightness of the internal space (5). Details of the airtightness index will be described later. The control unit (110) estimates the first flow rate based on the internal pressure during operation of the air pump (231) and the airtightness index. The estimation device (E) includes a differential pressure sensor (170), which is a first pressure detection unit, and an air pump (231) that supplies gas to the internal space (5). The estimation device (E) in this embodiment further includes an internal temperature sensor (51), an oxygen sensor (161), a carbon dioxide sensor (162), and a notification unit (115). The notification unit (115) has a display that shows predetermined information or a speaker that emits an alarm. Upon receiving predetermined information, the notification unit (115) displays or emits an alarm indicating that information. The notification unit (115) may be installed in the transport refrigeration unit (10).

[0113] (7) Operating Mode The operating modes of the air composition control device (100) are described below. The control unit (110) causes the air composition control device (100) to perform four operating modes. These operating modes include the 8% oxygen concentration mode, the 5% oxygen concentration mode, the outside air introduction mode, and the breathing mode. The 8% oxygen concentration mode and the 5% oxygen concentration mode are sometimes collectively referred to as the treated gas introduction mode.

[0114] The 8% oxygen concentration mode is an operating mode in which the air composition control device (100) supplies nitrogen-enriched gas with an average oxygen concentration of 8% to the interior space (5). The 5% oxygen concentration mode is an operating mode in which the air composition control device (100) supplies nitrogen-enriched gas with an average oxygen concentration of 5% to the interior space (5). The outside air introduction mode is an operating mode in which the air composition control device (100) supplies outside air directly to the interior space (5). The breathing mode is an operating mode in which the air composition control device (100) stops supplying nitrogen-enriched gas and outside air to the interior space (5) in order to change the composition of the air inside the storage facility due to the breathing of the cargo inside the facility.

[0115] In these operating modes, the oxygen concentration of the gas supplied to the chamber increases in the order of 5% oxygen concentration mode, 8% oxygen concentration mode, and outside air introduction mode. The air composition control device (100) adjusts the air composition of the chamber space (5) by switching between these operating modes.

[0116] (7-1) Oxygen concentration 8% mode As shown in Figure 10, in the 8% oxygen concentration mode, the air composition adjustment device (100) repeatedly performs the first and second operations alternately. Between the first and second operations, the air composition adjustment device (100) performs a pressure equalization operation. During the pressure equalization operation, the control unit (110) opens the purge valve (251). This quickly equalizes the internal pressures of the first adsorption cylinder (234) and the second adsorption cylinder (235).

[0117] In the 8% oxygen concentration mode, the control unit (110) keeps the gas discharge valve (272) closed and the gas supply valve (273) open at all times. As a result, low-oxygen gas is supplied to the interior space (5) from the start of the first and second operations. In each operation, the oxygen concentration in the nitrogen-enriched gas changes over time. Specifically, at the beginning of each operation, nitrogen-enriched gas with a relatively high oxygen concentration is generated because outside air remains in the adsorption cylinders (234, 235) and piping, and at the end of each operation, more nitrogen components are desorbed because the pressure inside the adsorption cylinders decreases compared to the beginning, resulting in the generation of nitrogen-enriched gas with a relatively high oxygen concentration. In the 8% oxygen concentration mode, nitrogen-enriched gas is supplied to the interior space (5) from the start of the first and second operations, so the average oxygen concentration of the nitrogen-enriched gas over the entire duration of each operation is relatively high at 8%.

[0118] (7-2) Oxygen concentration 5% mode As shown in Figure 11, in the 5% oxygen concentration mode, the air composition adjuster (100) repeatedly performs the first and second operations alternately, similar to the 8% oxygen concentration mode. Between the first and second operations, the air composition adjuster (100) performs a pressure equalization operation.

[0119] In the 5% oxygen concentration mode, the control unit (110) causes the air composition adjustment device (100) to perform a gas discharge operation for a predetermined time (e.g., 4 seconds) from the start of the first operation. During the gas discharge operation, the control unit (110) opens the gas discharge valve (272) and closes the gas supply valve (273). As described above, a nitrogen-enriched gas with a relatively high oxygen concentration is generated at the beginning of each operation. By performing the gas discharge operation, the nitrogen-enriched gas with a relatively high oxygen concentration is not supplied to the interior space (5) but is discharged to the exterior space (6) via the gas discharge pipe (276). Thereafter, for the remainder of each operation, the control unit (110) closes the gas discharge valve (272) and opens the gas supply valve (273). Thus, in the 5% oxygen concentration mode, nitrogen-enriched gas is discharged into the space outside the chamber (6) from the start of the first or second operation until a predetermined time has elapsed. As a result, the average oxygen concentration of the nitrogen-enriched gas over the entire duration of each operation is relatively low at 5%.

[0120] (7-3) Outdoor air intake mode In the outside air intake mode, outside air from the outside space (6) is supplied directly to the inside space (5). In the outside air intake mode, the control unit (110) causes the air composition adjustment device (100) to perform the outside air intake operation described above. The oxygen concentration of the outside air is approximately 21%. The outside air intake mode can increase the oxygen concentration of the air inside the storage unit.

[0121] (7-4) Breathing Modes In breathing mode, the control unit (110) stops the air pump (231) and closes the gas discharge valve (272) and the measuring on / off valve (282). In breathing mode, nitrogen-enriched gas and outside air are not supplied to the interior space (5). As a result, the oxygen concentration in the interior air decreases and the carbon dioxide concentration increases as the cargo breathes.

[0122] (8) Airtightness index The estimation device (E) of this embodiment determines the Cv value of the internal space (5). The Cv value is an airtightness index that indicates the airtightness of the internal space (5) of the transport container (1). The smaller the Cv value, the higher the airtightness, and the less likely it is that the air inside the internal space (5) will leak out into the external space (6). The larger the Cv value, the higher the airtightness, and the more likely it is that the air inside the internal space (5) will leak out into the external space (6). For example, if the Cv value is 3.33 or less, the airtightness of the transport container (1) is relatively high, so the internal air can be sufficiently cooled by the transport refrigeration device (10), and the composition of the internal air can be sufficiently adjusted by the air composition adjustment device (100). For example, if the Cv value is greater than 3.33 and less than 4.12, the internal air can be sufficiently cooled by the transport refrigeration device (10), but it becomes difficult to adjust the composition of the internal air by the air composition adjustment device (100). For example, if the Cv value is 4.12 or higher, it becomes difficult to cool the internal air by the transport refrigeration unit (10) and to adjust the composition of the internal air by the air composition adjustment unit (100). Thus, the Cv value is useful for evaluating the airtightness performance of the transport container (1).

[0123] The estimation device (E) performs an airtightness measurement mode to determine the Cv value. The airtightness measurement mode in this embodiment includes a first airtightness measurement mode, a second airtightness measurement mode, and a third airtightness measurement mode. The first airtightness estimation mode is a mode that measures the Cv value using the depressurization method. The second airtightness estimation mode is a mode that measures the Cv value using the pressure increase method. The third airtightness estimation mode is a mode that measures the Cv value using the constant pressure method. Details of each airtightness estimation mode will be described below.

[0124] (8-1) First airtightness measurement mode (depressurization method) In the first airtightness measurement mode, the Cv value is automatically measured by the depressurization method. The estimation device (E) increases the internal pressure of the storage space (5) by operating the air pump (231) as a pressure regulating unit. The estimation device (E) then determines the Cv value based on the rate of decrease in the internal pressure.

[0125] Specifically, as shown in Figure 12, in step ST11, the control unit (110) operates the air pump (231) as a pressure regulating unit. In step ST11, the control unit (110) closes the gas discharge valve (272), the measuring on / off valve (282), and the ventilation exhaust valve (151), and completely closes the supply air passage (41) and exhaust passage (42) of the ventilation device (40). In step ST11, the air composition adjustment device (100) opens the bypass valve (256) and the gas supply valve (273) in the same manner as the outside air introduction operation described above, and supplies outside air directly into the interior space (5) by the pressurizing pump (231a). However, as will be described in detail later, the air composition adjustment device (100) may close the bypass valve (256), open the gas supply valve (273), and supply the gas processed in the air processing unit (95) to the chamber space (5) by the pressure reducing pump (231b), similar to the gas supply operation described above.

[0126] When air is introduced into the internal space (5), the internal pressure (Pi) increases in step ST12. In step ST13, the control unit (110) stops the air pump (231) when the internal pressure (Pi) exceeds the first pressure (P1). The internal pressure (Pi) is determined by the differential pressure (ΔP) detected by the differential pressure sensor (170). The differential pressure (ΔP) is the difference between the internal pressure (Pi) and the external pressure (Po) (ΔP = Pi - Po). In this embodiment, the external pressure (Po) is set to atmospheric pressure (101.3 [kPa]). The control unit (110) calculates the internal pressure (Pi) by adding the external pressure (Po) (atmospheric pressure) to the differential pressure (ΔP).

[0127] In step ST14, the control unit (110) measures the first time (Δt1) until the internal pressure (Pi) decreases from the first pressure (P1) to the second pressure (P2). In the first airtightness measurement mode, the first pressure (P1) is greater than the second pressure (P2). For example, the first pressure (P1) is set to 300 [kPa] and the second pressure (P2) is set to 100 [kPa]. As shown in Figure 12, the control unit (110) measures the first time (Δt1) from the first time point (t1) when the internal pressure (Pi) is the first pressure (P1) to the second time point (t2) when the internal pressure (Pi) is the second pressure (P2). If the airtightness of the transport container (1) is low, the rate of decrease in internal pressure (Pi) increases, so the first time (Δt1) becomes shorter. If the airtightness of the transport container (1) is high, the rate of decrease in internal pressure (Pi) will be low, and the first time (Δt1) will be longer. Thus, the rate of decrease in internal pressure, or more precisely, the time it takes for the internal pressure to decrease to a predetermined pressure, serves as an indicator of the airtightness of the transport container (1).

[0128] Next, in step ST15, the control unit (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), and internal air temperature (Tr) when the internal pressure (Pi) reaches the second pressure (P2). Next, in step ST16, the control unit (110) calculates the Cv value based on equations (1), (2), and (3) in Figure 12. Here, Qo is the outflow rate of gas flowing out of the internal space (5) at the first time (Δt1) [m³ 3Qi is the flow rate of gas flowing into the storage space (5) at the first time (Δt1) [m 3 The formula is [ / h]. G is the specific gravity of the gas (air) (=1.0). Tr is the internal air temperature, i.e., the temperature detected by the internal temperature sensor (51). P1 is the internal pressure at the first time point (t1) (first pressure (P1)). P2 is the internal pressure at the second time point (t2) (second pressure (P2)). V1 is the volume of gas present in the internal space (5) at the first time point (t1). If no cargo is loaded into the internal space (5), V1 corresponds to the total volume when the internal space (5) is empty. V2 is the volume of gas in the internal space (5) at the second time point (t2). Δt1 is the first hour. Equation (1) is the basic formula for calculating the Cv value, equation (2) is a theoretical formula based on the equation of state in constant volume and isothermal change, and equation (3) is a theoretical formula for calculating V2.

[0129] In the depressurization method, the air pump (231) is stopped at the first time (Δt1), so Qi becomes zero. Therefore, Qo can be determined based on equations (2) and (3). By substituting Qo and other parameters into equation (1), the Cv value can be obtained. The control unit (110) may determine the Cv value using a function that includes these equations, or it may determine the Cv value based on a data table that includes these relationships.

[0130] (8-2) Second airtightness measurement mode (pressure boosting method) In the second airtightness measurement mode, the Cv value is automatically measured using the pressure boosting method. The estimation device (E) increases the internal pressure of the storage space (5) by operating the air pump (231) as a pressure regulating unit. The estimation device (E) determines the Cv value based on the rate of increase of the internal pressure at this time.

[0131] Specifically, as shown in Figure 13, in step ST21, the control unit (110) operates the air pump (231) as a pressure regulating unit. The details of the control in step ST21 are the same as in step ST11.

[0132] In step ST22, the control unit (110) measures the first time (Δt1) until the internal pressure (Pi) rises from the first pressure (P1) to the second pressure (P2). In the second airtightness measurement mode, the first pressure (P1) is smaller than the second pressure (P2). For example, the first pressure (P1) is set to 100 [kPa] and the second pressure (P2) is set to 300 [kPa]. As shown in Figure 13, the control unit (110) measures the first time (Δt1) from the first time point (t1) when the internal pressure (Pi) is the first pressure (P1) to the second time point (t2) when the internal pressure (Pi) is the second pressure (P2). If the airtightness of the transport container (1) is low, the rate of increase of the internal pressure (Pi) will be lower, and the first time (Δt1) will be longer. If the airtightness of the transport container (1) is high, the rate of increase in internal pressure (Pi) will be high, and the first time (Δt1) will be shorter. Thus, the rate of increase in internal pressure, or more precisely, the time it takes for the internal pressure to increase to a predetermined pressure, serves as an indicator of the airtightness of the transport container (1).

[0133] Next, in step ST23, the control unit (110) acquires the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), internal air temperature (Tr), and inflow flow rate (Qi) when the internal pressure (Pi) reaches the second pressure (P2). In the pressure boosting method, the inflow flow rate (Qi) corresponds to the control flow rate of the air pump (231). More precisely, when air is transported into the internal space (5) by the pressurizing pump (231a), the inflow flow rate (Qi) is the control flow rate of the pressurizing pump (231a), and when air is transported by the depressurizing pump (231b), it is the control flow rate of the depressurizing pump (231b). Alternatively, a flow meter may be installed in the flow path supplying air to the internal space (5) to directly measure the inflow flow rate (Qi).

[0134] Next, in step ST24, the control unit (110) calculates the Cv value based on equations (1), (2), and (3) in Figure 13. The details of the method for calculating the Cv value are the same as in the first airtightness measurement mode.

[0135] (8-3) Third airtightness measurement mode (constant pressure method) In the third airtightness measurement mode, the Cv value is automatically measured using the constant pressure method. The estimation device (E) operates the air pump (231) as a pressure regulator. When the air pump (231) reaches a steady state, the internal pressure in the storage space (5) becomes constant. The estimation device (E) uses parameters such as the internal pressure (Pi) at this time to determine the Cv value.

[0136] Specifically, as shown in Figure 14, in step ST31, the control unit (110) operates the air pump (231) which acts as a pressure regulator. The details of the control in step ST31 are the same as in step ST11.

[0137] Next, in step ST32, the control unit (110) determines whether the internal pressure (Pi) is constant. Here, "constant" means not only that the internal pressure (Pi) is maintained at a single value, but also that the internal pressure (Pi) is maintained within a predetermined range. In step ST32, the control unit (110) determines whether the internal pressure (Pi) is within a predetermined range over a predetermined second time (Δt2). If the internal pressure (Pi) is constant over the predetermined second time (Δt2), the process proceeds to step ST33.

[0138] In step ST33, the control unit (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), internal air temperature (Tr), and inflow rate (Qi) at the second time (Δt2). Here, these parameters may be values ​​at a specific point in the second time (Δt2) or may be average values ​​over the entire second time (Δt2). Then, in step ST34, the control unit (110) calculates the Cv value based on equation (1) shown in Figure 14. When the internal pressure (Pi) is constant, the inflow rate (Qi) and outflow rate (Qo) are balanced. Therefore, the inflow rate (Qi) and outflow rate (Qo) at the second time (Δt2) are equal. Therefore, the Cv value can be determined by substituting the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), internal air temperature (Tr), and inflow rate (Qi) at the second time (Δt2) into equation (4). Here, the inflow rate (Qi) is the control flow rate of the pressurizing pump (231a) when air is transported into the internal space (5) by the pressurizing pump (231a), and the control flow rate of the depressurizing pump (231b) when air is transported by the depressurizing pump (231b). Alternatively, a flow meter may be installed in the flow path supplying air to the internal space (5) to directly measure the inflow rate (Qi).

[0139] (9) Air pump malfunction detection The estimation device (E) of this embodiment determines an abnormality in the air pump (231). Specifically, the control unit (110) estimates a first flow rate, which is the flow rate of the gas to be treated flowing into the internal space (5), based on the internal pressure during operation of the air pump (231) and the airtightness index of the internal space (5). The control unit (110) evaluates the abnormality of the air pump (231) based on the estimated first flow rate. Below, an example will be described in which the control unit (110) estimates the flow rate of the gas to be treated with an oxygen concentration of 8% in the process in which the air composition adjustment device (100) sequentially executes an outside air introduction mode (first mode) in which outside air is introduced into the internal space (5) without changing its composition, and an 8% oxygen concentration mode (second mode) in which the gas to be treated is introduced into the internal space (5).

[0140] In step ST41, the control unit (110) determines the Cv value of the internal space (5) in the outside air introduction mode. Because the pressure in the internal space (5) increases due to the introduction of outside air, the control unit (110) determines the Cv value of the internal space (5) using the first airtightness measurement mode.

[0141] In step ST42, the control unit (110) determines whether the internal pressure is constant in the 8% oxygen concentration mode. If it is determined that the internal pressure is constant (YES in step ST42), step ST43 is executed. If it is determined that the internal pressure is not constant (NO in step ST43), step ST43 is executed again.

[0142] In step ST43, the control unit (110) estimates the first flow rate of the gas to be treated with an oxygen concentration of 8%. Specifically, the control unit (110) uses the Cv obtained in step S41 to determine the first flow rate Qp of the gas to be treated with an oxygen concentration of 8% using the third airtight measurement mode.

[0143] In step ST44, the control unit (110) determines whether the first flow rate Qp estimated in step ST43 is equal to or greater than the preset flow rate Q1 of the 8% oxygen concentration gas to be treated. If the flow rate Q1 is equal to or greater than the first flow rate Qp, it can be determined that the depressurizing pump (231b) is transporting the gas to be treated at a normal flow rate into the chamber space (5). On the other hand, if the flow rate Q1 is lower than the first flow rate Qp, it can be determined that the gas to be treated at a normal flow rate is not flowing from the depressurizing pump (231b) into the chamber space (5), and that there is a malfunction in the depressurizing pump (231b). If it is determined that the flow rate Q1 is equal to or greater than the first flow rate Qp (YES in step ST44), it is determined that the air pump (231) is functioning normally, and this control is terminated. If it is determined that the flow rate Q1 is lower than the first flow rate Qp (NO in step ST44), it is determined that the air pump (231) is not functioning normally, and step ST45 is executed.

[0144] In step ST45, the control unit (110) outputs a signal to the notification unit (115) indicating that the pressure-reducing pump (231b) of the air pump (231) is malfunctioning. Upon receiving the signal, the notification unit (115) issues an alarm.

[0145] (10) Features (10-1) Feature 1 In the estimation device (E) of this embodiment, the control unit (110) estimates a first flow rate, which is the flow rate of gas supplied to the internal space (5), based on the internal pressure and airtightness index during operation of the air pump (231).

[0146] According to this, the flow rate of gas supplied to the internal space (5) can be estimated, eliminating the need for measuring sensors. Therefore, it is possible to suppress the increase in the number of parts and cost increase that would otherwise be incurred by installing sensors.

[0147] (10-2) Feature 2 In this embodiment, the air pump (231) is provided in an air composition adjustment device (100) that adjusts the composition of the air in the internal space (5). The air pump (231) has a pressurizing pump (231a) that transports outside air to the internal space (5) and a depressurizing pump (231b) that transports the gas to be treated, which has a different composition from the outside air, to the internal space (5). The first flow rate is the flow rate of the gas to be treated transported to the internal space (5) by the depressurizing pump (231b).

[0148] According to this, the flow rate of the gas to be treated that the pressure-reducing pump (231b) transports to the chamber space (5) during the operation of the air composition adjustment device (100) can be estimated.

[0149] (10-3) Feature 3 In this embodiment, the control unit (110) estimates the first flow rate Qp based on the airtightness index when outside air is supplied to the internal space (5) by the pressurizing pump (231a). In the outside air introduction mode, outside air is supplied to the internal space (5) by the pressurizing pump (231a). Therefore, the airtightness index Cv of the internal space (5) can be determined in the outside air introduction mode. The flow rate of the gas to be treated can be estimated using this Cv as the true value.

[0150] (10-4) Feature 4 In this embodiment, during the process in which the air composition adjustment device (100) sequentially executes the outside air introduction mode and the gas to be treated introduction mode, the control unit (110) estimates the first flow rate Qp of the gas to be treated. In this way, the flow rate Qp of the gas to be treated can be estimated when the outside air introduction mode and the gas to be treated introduction mode are executed sequentially.

[0151] (10-5) Feature 5 In this embodiment, the control unit (110) evaluates the abnormality of the air pump (231) based on the estimated first flow rate. If the estimated first flow rate Qp of the gas to be treated is equal to or greater than the preset flow rate Q1 of the gas to be treated, it can be determined that the air pump (231) is operating normally. On the other hand, if the estimated first flow rate Qp of the gas to be treated is lower than the preset flow rate Q1 of the gas to be treated, it can be determined that the gas to be treated is not being transported normally from the pressure-reducing pump (231b). For example, if a packing or the like provided in the pressure-reducing pump (231b) is damaged, the pressure-reducing pump (231b) cannot draw a set amount of gas to be treated from the air processing unit (95). Therefore, the pressure-reducing pump (231b) cannot supply a sufficient amount of gas to be treated to the chamber space (5). In this way, an abnormality of the air pump (231) can be determined while the air composition adjustment device (100) is in operation. Therefore, periodic parts replacement and inspection of the air pump (231) can be eliminated, and parts that do not yet need replacing can be prevented from being replaced, thus reducing cost increases. In particular, the estimation device (E) of this embodiment can be used to determine abnormalities in the pressure-reducing pump (231b). Furthermore, abnormalities in the air pump (231) can be determined even while the transport container (1) is being transported.

[0152] (10-6) Feature 6 In this embodiment, the internal pressure is detected by a differential pressure sensor (170). When the pressure of the outside air is set to standard atmospheric pressure, the pressure inside the storage space (5) can be detected by the differential pressure.

[0153] (10-7) Feature 7 The transport refrigeration system (10) of this embodiment includes an estimation device (E) and a refrigerant circuit (11) for cooling the internal space (5). This provides a refrigeration cycle system capable of estimating the flow rate of gas into the internal space (5). In particular, when the cargo in the container (1) is perishable food, in addition to temperature control of the internal space (5), control of the air composition is necessary, so estimating the flow rate of gas into the internal space (5) is useful for transporting such cargo.

[0154] (11) Modified examples of embodiments The above-described embodiment may also have the following modified configuration. In principle, the differences from the above embodiment will be explained below.

[0155] (11-1) Modification 1: Pressure detection unit As shown in Figure 16, the main body case (171) of the differential pressure sensor (170), which is the pressure detection unit, is located in the external space (6). Specifically, the main body case (171) is located in the external equipment room (28). The external communication passage (174) is composed of a communication hole formed in the main body case (171), connecting the external space (6) with the inside of the main body case (171). The internal communication passage (173) is formed inside a tube. The tube extends from the main body case (171) to the internal space (5). The differential pressure sensor (170) detects the differential pressure (ΔP) between the internal space (5) and the external space (6). The control unit (110) takes the external pressure as atmospheric pressure and calculates the internal pressure (Pi) based on the differential pressure (ΔP).

[0156] (11-2) Modified example 2: Pressure detection unit As shown in Figure 17, the estimation device (E) may have an internal pressure sensor (170) as a first pressure detection unit and an external pressure sensor (180) as a second pressure detection unit for detecting the pressure of the air outside the storage unit. The internal pressure sensor (170) and the external pressure sensor (180) are separate and independent sensors. The internal pressure sensor is located in the internal space (5). Specifically, the internal pressure sensor is located in the primary flow path (29a) of the internal air flow path (29). The external pressure sensor is located in the external space (6). Specifically, the external pressure sensor is located in the external equipment room (28). The internal pressure sensor detects the internal pressure (Pi), and the external pressure sensor detects the external pressure (Po). The control unit (110) calculates the differential pressure (ΔP) by subtracting the external pressure from the internal pressure (Pi).

[0157] Alternatively, the estimation device (E) may have only an internal pressure sensor. The internal pressure sensor is placed in the internal space (5). Specifically, the internal pressure sensor is placed in the primary flow path (29a) of the internal air flow path (29). The control unit (110) takes the external pressure as atmospheric pressure and calculates the differential pressure (ΔP) by subtracting the atmospheric pressure from the internal pressure (Pi).

[0158] (12) Other embodiments The estimation device (E) may estimate the flow rate of gaseous outside air introduced into the interior space (5). In this case, the estimation device (E) may indicate an abnormality in the pressurizing pump (231a), which is the first transport unit of the air pump (231).

[0159] The estimation device (E) may also perform a fault detection of the gas discharge valve (272). For example, when the control unit (110), which is running in 8% oxygen concentration mode, switches to 5% oxygen concentration mode, the gas discharge valve (272) opens and a gas discharge operation is performed. During the gas discharge operation, a predetermined amount of gas is not supplied to the internal space (5) but is discharged to the external space (6) via the gas discharge pipe (276), causing the internal space (5) to depressurize. Using this, the estimation device (E) determines whether the gas discharge valve (272) is operating normally based on the change in internal pressure.

[0160] The estimation device (E) does not have to be applied to the air composition adjustment device (100). In this case, the supply unit (231a, 231b) does not have to be the air pump (231) of the above embodiment, but any unit that supplies gas to the internal space (5). For example, the control unit (110) has a data set of the airtightness index of the internal space (5) that has been determined in advance, and may use this data to estimate the first flow rate using one of the first to third airtightness measurement modes.

[0161] The estimation device (E) only needs to be able to estimate the first flow rate of the gas supplied to the interior space (5), and does not need to be able to determine if there is an abnormality in the supply unit, the air pump (231).

[0162] The estimation device (E) is not limited to determining the first flow rate by sequentially operating the first mode, which is the outside air introduction mode, and the second mode, which is the treated gas introduction mode.

[0163] In an operation process that sequentially performs the outside air introduction mode and the treated air introduction mode, if the air composition adjustment device (100) performs the 5% oxygen concentration mode after performing the 8% oxygen concentration mode, the estimation device (E) may use the Cv obtained in the outside air introduction mode to estimate the flow rate of the treated gas with an oxygen concentration of 5% as the first flow rate Qp. Alternatively, the estimation device (E) may determine if there is an abnormality in the air pump (231) based on the first flow rate Qp of the treated gas with an oxygen concentration of 5%. When the control unit (110) determines that the first flow rate Qp of the treated gas with an oxygen concentration of 5% is equal to or greater than the preset flow rate Q1 of the treated gas with an oxygen concentration of 5%, it can determine that the depressurizing pump (231b) is functioning normally. On the other hand, when the control unit (110) determines that the first flow rate Qp of the treated gas with an oxygen concentration of 5% is lower than the preset flow rate Q1 of the treated gas with an oxygen concentration of 5%, it can determine that there is an abnormality in the depressurizing pump (231b). Furthermore, abnormality of the air pump (231) may be determined based on both the first flow rate Qp in the 8% oxygen concentration mode and the first flow rate Qp in the 5% oxygen concentration mode. For example, the estimation device (E) may estimate the first flow rate Qp for each of the 8% oxygen concentration mode and 5% oxygen concentration mode, and if the first flow rate Qp when the gas to be treated has an oxygen concentration of 8% is equal to or greater than the set flow rate Q1, and the first flow rate Qp when the gas to be treated has an oxygen concentration of 8% is equal to or greater than the set flow rate Q1, the air pump (231) may be determined to be normal.

[0164] The air processing unit (95) may be configured to separate the outside air (atmosphere) into nitrogen-enriched gas and oxygen-enriched gas using a gas separation membrane. The gas separation membrane has the characteristic that the nitrogen permeation rate is lower than both the oxygen permeation rate and the carbon dioxide permeation rate. Therefore, in the air processing unit (95), the outside air is separated into oxygen-enriched gas that has permeated through the gas separation membrane and nitrogen-enriched gas that has not permeated through the gas separation membrane.

[0165] The transport container (1) may be a container for land transport, such as by truck or rail. The transport container (1) does not need to have an air cooling function.

[0166] The estimation device (E) may be provided in a transport refrigeration system (10) that does not have an air composition adjustment device (100). In this case, the transport refrigeration system (10) has an estimation device (E) which includes a pressure adjustment unit other than the air pump (231), a pressure detection unit, and a control unit (110).

[0167] Although the estimation device (E) of this embodiment has been described as being provided in a transport refrigeration system (10) having an air composition adjustment device (100), the estimation device (E) may also be provided in the air composition adjustment device (100), or the estimation device (E) may be configured separately from the transport refrigeration system (10) and the air composition adjustment device (100). The control unit (110) of the estimation device (E) may be provided in the transport refrigeration system (10), a server device, a terminal device operated by a user, etc. The control unit (110) may be composed of two or more physically separated control elements.

[0168] Although the air pump (231) in this embodiment has been described as being provided in a transport refrigeration system (10) having an air composition adjustment device (100), the estimation device (E) may be provided only in the air composition adjustment device (100).

[0169] While embodiments and modifications have been described above, it will be understood that a variety of changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the embodiments, modifications, and other embodiments described above may be combined or substituted as appropriate, as long as they do not impair the functions covered by this disclosure.

[0170] The designations "1st," "2nd," "3rd," etc., mentioned above are used to distinguish between the terms to which these designations are attached, and do not limit the number or order of those terms. [Industrial applicability]

[0171] As described above, this disclosure is useful for estimation devices, air composition adjustment devices, and transport refrigeration devices. [Explanation of Symbols]

[0172] 1. Shipping container (container) 5. Interior space 10. Refrigeration equipment for transport (refrigeration cycle equipment) 11 Refrigerant Circuit 100 Air composition adjustment device 110 Control Unit 170 Differential pressure sensor (first pressure detection unit) 180 External pressure sensor (second pressure detection unit) 231a Pressurized pump (first conveying section) 231a,231b Supply section 231b Pressure-reducing pump (second transport section) E estimation device

Claims

1. A supply unit (231a, 231b) that supplies gas to the internal space (5) of the container (1), A first pressure detection unit (170) detects the internal pressure, which is the pressure in the internal space (5) of the storage unit, The system includes a control unit (110) that determines an airtightness index, which is an indicator of the airtightness of the internal space (5) of the storage area, The control unit (110) estimates a first flow rate, which is the flow rate of the gas supplied to the internal space (5), based on the internal pressure and airtightness index during operation of the supply units (231a, 231b). Estimation device.

2. The supply units (231a, 231b) are provided in the air composition adjustment device (100) which adjusts the air composition in the internal space (5) of the chamber. The supply unit (231a, 231b) includes a first transport unit (231a) that transports outside air to the internal space (5), and a second transport unit (231b) that transports a gas to be processed, which has a different composition from the outside air, to the internal space (5). The first flow rate is the flow rate of the gas to be treated that is transported to the internal space (5) by the second transport unit (231b). The estimation device according to claim 1.

3. The control unit (110) estimates the first flow rate based on the airtightness index when outside air is supplied to the internal space (5) by the first transport unit (231a). The estimation device according to claim 2.

4. The air composition adjustment device (100) performs a first mode in which outside air is introduced into the internal space (5) without changing its composition, and a second mode in which the gas to be treated is introduced into the internal space (5). The control unit (110) estimates the first flow rate in the process of sequentially executing the first mode and the second mode. The estimation device according to claim 2 or 3.

5. The control unit (110) evaluates the abnormality of the supply unit (231a, 231b) based on the estimated first flow rate. The estimation device according to any one of claims 1 to 3.

6. The first pressure detection unit (170) includes a differential pressure sensor that detects the differential pressure between the outside air and the inside air of the storage unit. The estimation device according to any one of claims 1 to 3.

7. It further includes a second pressure detection unit (180) for detecting the pressure of the air outside the chamber, The control unit (110) determines the airtightness index based on the detected values ​​of the first pressure detection unit (170) and the second pressure detection unit (180). The estimation device according to any one of claims 1 to 3.

8. An estimation device (E) according to any one of claims 1 to 3, The chamber is equipped with a refrigerant circuit (11) for cooling the internal space (5). Refrigeration cycle device.

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