Estimation device, air composition adjustment device, and transport refrigeration device

Abstract

The present invention provides an estimation device capable of estimating the actual volume of the internal space of a shipping container. [Solution] The estimation device (E) includes a pressure adjustment unit (231) that changes the pressure in the internal space (5) of the transport container (1), a pressure detection unit (170) for determining the internal pressure (Pi) of the internal space (5), and a controller (110) that performs an estimation operation to estimate the actual volume of the internal space (5) based on a first index indicating the rate of change of the internal pressure (Pi) when the internal pressure (Pi) changes.

Description

Technical Field

[0001] The present disclosure relates to an estimation device, an air composition adjustment device, and a transport refrigeration 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 interior space of the container. The transport container has an air composition adjustment device that adjusts the composition of the interior air. The air composition adjustment device adjusts the oxygen concentration and the carbon dioxide concentration of the interior air.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Cargo such as fruits and flowers is loaded into the interior space of the transport container. When cargo is loaded into the interior space, the volume of the substantial space in the interior space, in other words, the actual volume of the interior air existing in the interior space changes. Hereinafter, this volume is referred to as the actual volume of the interior space. The actual volume of the interior space is useful for the management of the transport container.

[0005] The present disclosure is to provide an estimation device that can estimate the actual volume of the interior space of a transport container.

Means for Solving the Problems

[0006] The first embodiment relates to an estimation device (E). The estimation device (E) comprises a pressure adjustment unit (231) for changing the pressure in the internal space (5) of a transport container (1), a pressure detection unit (170) for determining the internal pressure (Pi) of the internal space (5), and a controller (110) that performs an estimation operation to estimate the actual volume of the internal space (5) based on a first index indicating the rate of change of the internal pressure (Pi) when the internal pressure (Pi) changes.

[0007] In the first embodiment, the pressure adjustment unit (231) changes the internal pressure (Pi). When cargo is loaded into the internal space (5) and the actual volume of the internal space (5) changes, the rate of change of the internal pressure (Pi) changes. Specifically, if the actual volume (Vs) increases, the rate of increase or decrease of the internal pressure (Pi) slows down, and if the actual volume (Vs) decreases, the rate of increase or decrease of the internal pressure (Pi) speeds up. Therefore, the controller (110) estimates the actual volume of the internal space (5) based on a first index that indicates the rate of change of the internal pressure (Pi).

[0008] In the second embodiment, the first indicator is an indicator showing the rate of increase in the internal pressure (Pi) as described in the first embodiment.

[0009] In the second embodiment, the controller (110) estimates the actual volume of the internal space (5) based on a first index indicating the rate of increase of the internal pressure (Pi).

[0010] In the third embodiment, the first indicator is an indicator showing the rate of decrease in the internal pressure (Pi) as described in the first embodiment.

[0011] In the third embodiment, the controller (110) estimates the actual volume of the internal space (5) based on a first indicator that shows the rate of decrease in the internal pressure (Pi).

[0012] In the fourth aspect, in the first aspect, the controller (110) estimates the actual volume of the transport container (1) based on the airtightness index and the first index during the estimation operation.

[0013] In the fourth embodiment, the controller (110) uses an airtightness index to determine the actual volume. This is because the airtightness index of the transport container (1), i.e., the ease with which air leaks between the outside and inside of the container, affects the rate of change of the internal pressure (Pi).

[0014] In the fifth aspect, in the fourth aspect, the controller (110) performs a first airtightness measurement mode in which it determines an airtightness index based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and an index indicating the rate of decrease in the internal pressure (Pi) when the internal pressure (Pi) decreases.

[0015] In the fifth embodiment, in the first airtightness measurement mode, external pressure (Po), internal pressure (Pi), and an index indicating the rate of decrease of internal pressure (Pi) are used. This is because external pressure (Po), internal pressure (Pi), and the rate of decrease of internal pressure are parameters that affect the airtightness index of the transport container (1).

[0016] In the sixth aspect, in the fourth aspect, the controller (110) performs a second airtightness measurement mode in which it determines an airtightness index based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and an index indicating the rate of increase of the internal pressure (Pi) when the internal pressure (Pi) increases.

[0017] In the sixth embodiment, in the second airtightness measurement mode, external pressure (Po), internal pressure (Pi), and an index indicating the rate of increase of internal pressure (Pi) are used. This is because external pressure (Po), internal pressure (Pi), and the rate of increase of internal pressure are parameters that affect the airtightness index of the transport container (1).

[0018] In the seventh embodiment, in the fifth or sixth embodiment, the controller (110) performs the first airtightness measurement mode or the second airtightness measurement mode when the storage space (5) is empty.

[0019] In the seventh aspect, when the internal space (5) is empty, the first airtightness measurement mode or the second airtightness measurement mode is executed. If the internal space (5) is empty, the actual volume (Vs) of the internal space (5) can be easily grasped. If the actual volume (Vs) is known, the airtightness index can be accurately obtained. This is because the actual volume (Vs) affects the rate of change of the internal pressure (Pi).

[0020] In the eighth aspect, in the fourth aspect, the pressure adjustment unit (231) is an air conveyance unit that supplies air to the internal space (5). The controller (110) executes a third airtightness measurement mode for obtaining an airtightness index based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and the inflow rate of the air supplied to the internal space (5) during a period when the internal pressure (Pi) is constant during the operation of the air conveyance unit (231).

[0021] In the eighth aspect, during a period when the internal pressure (Pi) is constant, an airtightness index is obtained based on the internal pressure (Pi), the external pressure (Po), and the inflow rate of the air supplied to the internal space (5). This is because if the internal pressure (Pi) is constant, these parameters affect the airtightness index.

[0022] In the ninth aspect, in the eighth aspect, the controller (110) executes the third airtightness measurement mode when there is cargo in the internal space (5).

[0023] In the ninth aspect, when there is cargo in the internal space (5), the third airtightness measurement mode is executed. The third airtightness measurement mode is an airtightness index measured when the internal pressure (Pi) is constant and is not affected by the actual volume of the internal space (5). Therefore, even when there is cargo in the internal space (5), the airtightness index can be accurately obtained.

[0024] In the tenth aspect, in the ninth aspect, the controller (110) estimates the actual volume based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and the first index in the estimation operation.

[0025] In the tenth aspect, the controller (110) further estimates the actual volume of the internal space (5) by using the external pressure (Po). This is because when there is air leakage in the transport container (1), the external pressure (Po) affects the rate of change of the internal pressure (Pi).

[0026] In the eleventh aspect, based on the tenth aspect, the pressure detection unit includes a differential pressure sensor (170) that detects the differential pressure between the external air and the internal air.

[0027] In the eleventh aspect, the differential pressure sensor (170) can detect the differential pressure between the external air and the internal air. If the differential pressure between the two is known and the external pressure is regarded as the atmospheric pressure, the internal pressure can be easily obtained.

[0028] The twelfth aspect is directed to an air composition adjustment device. The air composition adjustment device includes any one of the estimation devices (E) according to the first to eleventh aspects and an air treatment unit (95) that adjusts the composition of the air in the internal space (5).

[0029] In the twelfth aspect, an air composition adjustment device capable of estimating the actual volume of the internal space (5) can be provided.

[0030] In the thirteenth aspect, based on the twelfth aspect, the air composition adjustment device further includes an air pump (231) that supplies air to the internal space (5). The pressure adjustment unit (231) is constituted by the air pump (231).

[0031] In the thirteenth aspect, the air pump (231) also functions as a pressure adjustment unit for adjusting the internal pressure of the internal space (5).

[0032] In the fourteenth aspect, based on the twelfth or thirteenth aspect, the controller (110) estimates the respiration rate of the fruits, vegetables or flowers in the internal space (5) based on the actual volume of the internal space (5) and the oxygen concentration or carbon dioxide concentration of the internal air in the internal space (5).

[0033] In the 14th embodiment, the controller (110) estimates the respiration rate of fruits, vegetables, and flowers. If there are goods such as fruits, vegetables, and flowers in the storage space (5), the actual volume (Vs) can be known to determine the actual volume of air in the storage space (5). If the actual volume of the storage space, the oxygen and carbon dioxide concentrations of this air, and the changes in the oxygen and carbon dioxide concentrations are known, the respiration rate of fruits, vegetables, and flowers can be estimated.

[0034] The 15th embodiment relates to a transport refrigeration system (10). The transport refrigeration system (10) comprises one of the first to 11 presumptive devices (E) and a refrigerant circuit (11) for cooling the internal space of the storage unit.

[0035] In the 15th embodiment, a transport refrigeration device can be provided that can estimate the actual volume of the internal space (5). [Brief explanation of the drawing]

[0036] [Figure 1] Figure 1 is a schematic perspective view of a transport refrigeration system according to an embodiment. [Figure 2] Figure 2 is a cross-sectional view of a transport container equipped with a transport refrigeration device according to an embodiment. [Figure 3] Figure 3 is a piping diagram showing the refrigerant circuit of the transport refrigeration system of the embodiment. [Figure 4] Figure 4 is a schematic front view of the ventilation system. Figure 4(A) shows the lid in the closed position, Figure 4(B) shows the lid in the intermediate position, and Figure 4(C) shows the lid 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 controller 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 shows a flowchart, timing chart, and formulas to explain the first estimated action. [Figure 16] Figure 16 shows a flowchart, timing chart, and formulas to explain the second estimated operation. [Figure 17] Figure 17 is a conceptual diagram illustrating the timing of the airtightness measurement mode and the execution of the estimation operation in the first example. [Figure 18] Figure 18 is a conceptual diagram illustrating the timing of the airtightness measurement mode and the execution of the estimation operation in the second example. [Figure 19] Figure 19 is a table showing the relationship between the operating modes of the air composition control device and the first estimated operation and the second estimated operation. [Figure 20] Figure 20 is a flowchart showing the first control example after estimating the actual volume. [Figure 21] Figure 21 is a flowchart showing a second control example after estimating the actual volume. [Figure 22] Figure 22 is a flowchart showing a third control example after estimating the actual volume. [Figure 23] Figure 23 is a flowchart of the first respiratory volume estimation process. [Figure 24] Figure 24 is a flowchart of the second respiratory volume estimation process. [Figure 25] Figure 25 is a diagram corresponding to Figure 2 of the transport container in Modification Example 1. [Modes for carrying out the invention]

[0037] 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.

[0038] (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).

[0039] 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.

[0040] The container body (2) is a storage unit for the fresh produce mentioned above.

[0041] 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.

[0042] 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).

[0043] (2) Basic configuration of transport refrigeration equipment The transport refrigeration unit (10) comprises a casing (20), a refrigerant circuit (11) that performs the refrigeration cycle, an external fan (34), and an internal fan (35).

[0044] (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).

[0045] 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).

[0046] 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).

[0047] 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).

[0048] 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).

[0049] (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).

[0050] (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).

[0051] 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.

[0052] 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.

[0053] 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).

[0054] 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).

[0055] (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).

[0056] (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.

[0057] 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).

[0058] 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.

[0059] 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.

[0060] 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).

[0061] (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).

[0062] 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).

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] (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).

[0068] (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).

[0069] 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.

[0070] 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, which has a higher nitrogen concentration and a lower oxygen concentration than the outside air, and an oxygen-enriched gas, which has a lower nitrogen concentration and a higher oxygen concentration than the outside air.

[0071] (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.

[0072] 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).

[0073] (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).

[0074] (4-4) Air pump The air pump (231) is an example of a pressure regulating unit. 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).

[0075] 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).

[0076] 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).

[0077] (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).

[0078] (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).

[0079] (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).

[0080] 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.

[0081] (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.

[0082] 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).

[0083] 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).

[0084] (4-9) Adsorption cylinder Each of the first adsorption cylinder (234) and the second adsorption cylinder (235) is an adsorption unit 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.

[0085] 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).

[0086] 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).

[0087] (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.

[0088] 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.

[0089] (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).

[0090] 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).

[0091] (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).

[0092] 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).

[0093] (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).

[0094] 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.

[0095] (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).

[0096] (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).

[0097] 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).

[0098] (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).

[0099] 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.

[0100] (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).

[0101] 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).

[0102] 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).

[0103] 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).

[0104] 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.

[0105] 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).

[0106] (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.

[0107] (4-19) Differential pressure sensor and internal temperature sensor The air composition adjustment device (100) has a differential pressure sensor (170) as a 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) 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).

[0108] 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).

[0109] 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).

[0110] (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.

[0111] 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.

[0112] (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).

[0113] 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).

[0114] 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).

[0115] (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.

[0116] 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).

[0117] Meanwhile, the depressurization 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 is generated in the first adsorption cylinder (234) with a higher nitrogen concentration and lower oxygen concentration than the outside air. The nitrogen-enriched gas flows from the first adsorption cylinder (234) into the suction pipe (243) and is drawn into the depressurization pump (231b). The depressurization 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).

[0118] (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.

[0119] 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.

[0120] 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).

[0121] 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).

[0122] 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.

[0123] (6) Controller and estimation device The air composition adjustment device (100) has a controller (110). As shown in Figure 9, the controller (110) comprises 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.

[0124] The controller (110) controls the components of the air composition control device (100). The controller (110) receives the measured values ​​from the oxygen sensor (161) and the carbon dioxide sensor (162). The controller (110) controls the air pump (231), the first switching valve (136), and the second switching valve (137). The controller (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).

[0125] The controller (110) controls the ventilation device (40). Specifically, the controller (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).

[0126] The controller (110) is provided in the estimation device (E). The estimation device (E) estimates the actual volume (Vs) of the internal space (5). The estimation device (E) determines the Cv value as an airtightness index of the transport container (1). The estimation device (E) has a differential pressure sensor (170) which is a pressure detection unit and an air pump (231) which is a pressure adjustment unit. The estimation device (E) of this embodiment further has an internal temperature sensor (51), an oxygen sensor (161), and a carbon dioxide sensor (162).

[0127] (7) Operating Mode The operating modes of the air composition control device (100) are described below. The controller (110) causes the air composition control device (100) to perform four operating modes. These operating modes include an 8% oxygen concentration mode, a 5% oxygen concentration mode, an outside air intake mode, and a breathing mode.

[0128] 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.

[0129] 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.

[0130] (7-1) Oxygen concentration 8% mode As shown in Figure 10, in the 8% oxygen concentration mode, the air composition adjuster (100) repeatedly performs the first and second operations alternately. Between the first and second operations, the air composition adjuster (100) performs a pressure equalization operation. During the pressure equalization operation, the controller (110) opens the purge valve (251). This quickly equalizes the internal pressures of the first adsorption cylinder (234) and the second adsorption cylinder (235).

[0131] In the 8% oxygen concentration mode, the controller (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, the pressure inside the adsorption cylinders (234, 235) decreases from the initial state, so more nitrogen components are desorbed, and nitrogen-enriched gas with a relatively high oxygen concentration is generated. 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%.

[0132] (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.

[0133] In the 5% oxygen concentration mode, the controller (110) causes the air composition adjuster (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 controller (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 controller (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%.

[0134] (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 controller (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.

[0135] (7-4) Breathing Modes In breathing mode, the controller (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.

[0136] (8) Estimation of the internal volume of the storage space The transport container (1) has an estimation device (E) for estimating the actual volume (Vs) of the internal space (5). The actual volume (Vs) is the volume obtained by subtracting the total volume of the cargo loaded in the internal space (5) from the total volume of the internal space (5). In other words, the actual volume (Vs) is the effective volume of the actual space of the container body (2) and corresponds to the actual volume of the internal space (5). The controller (110) in this embodiment estimates the actual volume (Vs) based on the Cv value, which is an airtightness index, and a first index that indicates the rate of pressure change in the internal space (5).

[0137] (8-1) Measurement of Cv value The estimation device (E) of this embodiment estimates the actual volume (Vs) using the Cv value of the transport container (1). The Cv value is an airtightness index 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 container (5) will leak out into the outside space (6). The larger the Cv value, the higher the airtightness, and the more likely it is that the air inside the container (5) will leak out into the outside 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 transport refrigeration device (10) can sufficiently cool the air inside, and the air composition adjustment device (100) can sufficiently adjust the composition of the air inside. For example, if the Cv value is greater than 3.33 and less than 4.12, the transport refrigeration device (10) can sufficiently cool the air inside, but it becomes difficult to adjust the composition of the air inside using 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).

[0138] 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.

[0139] (8-1-1) 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.

[0140] Specifically, as shown in Figure 12, in step ST11, the controller (110) operates the air pump (231) as a pressure regulating unit. In step ST11, the controller (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.

[0141] When air is introduced into the internal space (5), the internal pressure (Pi) increases in step ST12. In step ST13, the controller (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 controller (110) calculates the internal pressure (Pi) by adding the external pressure (Po) (atmospheric pressure) to the differential pressure (ΔP).

[0142] In step ST14, the controller (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 controller (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).

[0143] Next, in step ST15, the controller (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 controller (110) calculates the Cv value based on equations (1), (2), and (3) in Figure 12. Here, Qo is the outflow rate of gas [m³] flowing out of the internal space (5) at the first time (Δt1). 3 Qi is the flow rate of gas flowing into the storage space (5) at the first time (Δt1) [m 3The 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.

[0144] 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 controller (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.

[0145] (8-1-2) 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.

[0146] Specifically, as shown in Figure 13, in step ST21, the controller (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.

[0147] In step ST22, the controller (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 lower 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 controller (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 therefore 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).

[0148] Next, in step ST23, the controller (110) obtains 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, the inflow flow 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 flow rate (Qi).

[0149] Next, in step ST24, the controller (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.

[0150] (8-1-3) 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.

[0151] Specifically, as shown in Figure 14, in step ST31, the controller (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.

[0152] Next, in step ST32, the controller (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 controller (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.

[0153] In step ST33, the controller (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 controller (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).

[0154] (8-2) Estimation of the actual volume of the interior space The estimation device (E) performs an estimation operation to estimate the actual volume (Vs) of the internal space (5). In the estimation operation of this embodiment, the controller (110) estimates the actual volume (Vs) of the internal space (5) based on the Cv value obtained in one of the airtightness measurement modes described above and a first index indicating the rate of change of the internal pressure (Pi). The estimation operation includes a first estimation operation based on the depressurization method and a second estimation operation based on the pressure boosting method.

[0155] (8-2-1) First estimated operation The first estimation operation estimates the actual volume (Vs) of the internal space (5) based on a first indicator that shows the rate of change in the decrease of the internal pressure. For example, when cargo is loaded into the internal space (5) and the actual volume (Vs) decreases, the rate of decrease of the internal pressure (Pi) in the depressurization method increases. Conversely, for example, when the amount of cargo in the internal space (5) decreases and the actual volume (Vs) increases, the rate of decrease of the internal pressure (Pi) in the depressurization method decreases. Therefore, in the first estimation operation, the actual volume (Vs) is estimated using the first time (Δt1) in the depressurization method for the internal pressure (Pi) as the first indicator. The estimation device (E) performs the first estimation operation shown in Figure 15 after the airtightness measurement mode described above.

[0156] The processing in steps ST41 to ST45 of the first estimation operation is the same as steps ST11 to ST15 of the first airtightness measurement mode described above. That is, in steps ST41 to ST44, the controller (110) measures the first time (Δt1) until the internal pressure (Pi) decreases from the first pressure (P1) to the second pressure (P2). In step ST45, the controller (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), and internal air temperature (Tr).

[0157] Next, in step ST46, the controller (110) refers to the Cv value obtained in the airtightness measurement mode. This Cv value may be the value obtained in any of the first airtightness measurement mode, the second airtightness measurement mode, or the third airtightness measurement mode.

[0158] Next, in step ST47, the controller (110) uses the parameters obtained in steps ST44 to ST46 to determine the actual volume (Vs) based on equations (1), (2), and (3). In equation (1), the Cv value measured in airtightness measurement mode is used. Therefore, the outflow rate (Qo) can be determined from equation (1). By substituting this outflow rate (Qo) and the other parameters into equations (2) and (3), V1 can be determined. V1 is the gas volume of the storage space (5), that is, the actual volume (Vs) obtained by subtracting the volume of the cargo from the total volume of the storage space (5).

[0159] (8-2-2) Second estimated operation The second estimation operation estimates the actual volume (Vs) of the internal space (5) based on a first indicator that shows the rate of increase in the internal pressure. For example, when cargo is loaded into the internal space (5) and the actual volume (Vs) decreases, the rate of increase in the internal pressure (Pi) in the pressure-boosting method increases. Conversely, for example, when the amount of cargo in the internal space (5) decreases and the actual volume (Vs) increases, the rate of increase in the internal pressure (Pi) in the pressure-boosting method decreases. Therefore, in the second estimation operation, the actual volume (Vs) is estimated using the first time (Δt1) in the pressure-boosting method for the internal pressure (Pi) as the first indicator. The estimation device (E) performs the second estimation operation shown in Figure 16 after the airtightness measurement mode described above.

[0160] The processing in steps ST51 to ST53 of the second estimation operation is the same as steps ST21 to ST23 of the second airtightness measurement mode described above. That is, in steps ST51 and ST52, the controller (110) measures the first time (Δt1) until the internal pressure (Pi) increases from the first pressure (P1) to the second pressure (P2). In step ST53, the controller (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), internal air temperature (Tr), and inflow flow rate (Qi).

[0161] Next, in step ST54, the controller (110) refers to the Cv value obtained in the airtightness measurement mode. This Cv value may be the value obtained in the first airtightness measurement mode, the second airtightness measurement mode, or the third airtightness measurement mode. Next, in step ST55, the controller (110) uses the parameters obtained in steps ST53 and ST54 to determine the actual volume (Vs) based on equations (1), (2), and (3) in the same manner as in the first estimation operation.

[0162] (8-3) Airtightness measurement mode and timing of estimated operation The transport container (1) is transported from the repair shop (terminal) to a cargo shipping destination such as a farm, and then transported to the delivery location by a container ship or the like. This document describes the airtightness measurement mode and the timing of the execution of the estimated operation during transport of such a transport container (1).

[0163] (8-3-1) Example 1 In the first example shown in Figure 17, the transport container (1) is transported to the delivery location via the repair workshop and cargo shipping point A. During period a, from the repair workshop to cargo shipping point A, the internal space (5) is empty. During period a, the Cv value can be determined using one of the first airtightness measurement mode, the second airtightness measurement mode, or the third airtightness measurement mode.

[0164] In the first and second airtightness measurement modes, in order to determine the Cv value from equations (2) and (3), the gas volume V1 at the first time point (t1), in other words, the actual volume (Vs) of the internal space (5), is required. In period a, the internal space (5) is empty, so the actual volume (Vs) of the internal space (5) corresponds to the total volume of the internal space (5). The total volume of the internal space (5) is determined by the specifications of the transport container (1). Therefore, in period a, the Cv value can be measured in the first and second airtightness measurement modes by referring to this total volume.

[0165] Specifically, the controller (110) stores the total volume of the storage space (5) that has been set in advance, or the total volume that the operator entered during period a. When the storage space (5) is empty, the controller (110) determines the Cv value based on the total volume of the storage space (5) and an index indicating the rate of pressure change in the storage space (5) using either the first airtightness measurement mode or the second airtightness measurement mode.

[0166] Furthermore, in period a, when measuring the Cv value using the third airtightness measurement mode, V1, i.e., the total volume of the internal space (5), is not required. This is because, as shown in Figure 14, the Cv value can be determined in the third airtightness measurement mode without using V1. When the internal space (5) is empty, the controller (110) uses the third airtightness measurement mode to determine the Cv value based on an index indicating the rate of pressure change in the internal space (5), without using the total volume of the internal space (5). Furthermore, as shown in Figure 17, in period a, the Cv value may also be determined using measuring equipment located in the repair workshop.

[0167] When the transport container (1) arrives at the cargo shipping destination A, cargo A is loaded into the storage space (5). Therefore, during period b, from the cargo shipping destination A to the delivery location, cargo A is loaded into the storage space (5). In the storage space (5), the actual volume (Vs) is reduced by the volume of cargo A. However, during period b, the actual volume (Vs) of the storage space (5) can be estimated using the Cv value obtained in period a by the first or second estimation operation. Thus, when cargo is loaded into the storage space (5), the controller (110) estimates the actual volume (Vs) of the storage space (5) by the first or second estimation operation, based on the Cv value when the storage space (5) is empty and a first index indicating the rate of pressure change in the storage space.

[0168] (8-3-2) Second example In the second example shown in Figure 18, a transport container (1) is transported to cargo origin B, then to the delivery location via cargo origin C. During period c, from cargo origin B to cargo origin C, cargo B is loaded into the warehouse space (5). During period c, the estimation device (E) determines the Cv value using the third airtightness measurement mode.

[0169] During period c, cargo B is loaded into the storage space (5), so the actual volume (Vs) of the storage space (5) is smaller than the total volume of the storage space (5). For this reason, in the first airtightness measurement mode and the second airtightness measurement mode, the Cv value cannot be determined unless the actual volume (Vs) of the storage space (5) is known. In contrast, as shown in Figure 14, the third airtightness measurement mode can determine the Cv value without using V1, i.e., the actual volume (Vs). Therefore, the controller (110) can determine the Cv value even during period c using the third airtightness measurement mode.

[0170] When the transport container (1) arrives at the cargo shipping destination C, cargo C is loaded into the storage space (5). Therefore, during the period d from the cargo shipping destination C to the delivery location, cargo B and cargo C are loaded into the storage space (5). In the storage space (5), the actual volume (Vs) is reduced by the volume of cargo B and C. However, during period d, the actual volume (Vs) of the storage space (5) can be estimated using the Cv value obtained in the third airtightness measurement mode by the first or second estimation operation. In this way, when cargo is loaded into the storage space (5), the controller (110) estimates the actual volume (Vs) of the storage space (5) in the first or second estimation operation based on the Cv value obtained by the constant pressure method and an index indicating the rate of pressure change in the storage space.

[0171] (8-4) Timing of estimated actions The estimation device (E) can perform estimation operations in conjunction with the operating mode of the air composition adjustment device (100). This will be explained with reference to Figure 19.

[0172] As shown in Figure 19(a), the controller (110) performs the first estimation operation after switching from the outside air introduction operation (more precisely, the outside air introduction mode) to the breathing mode. In the outside air introduction operation, outside air is supplied to the interior space (5) by the pressurizing pump (231a), increasing the internal pressure (Pi). Subsequently, in breathing mode, the pressurizing pump (231a) stops. Therefore, in breathing mode, the first time (Δt1) until the internal pressure (Pi) decreases from the first pressure (P1) to the second pressure (P2) can be measured, and furthermore, the actual volume (Vs) can be determined.

[0173] As shown in Figure 19(b), the controller (110) performs the first estimation operation after switching from the gas supply operation (more precisely, the 5% oxygen mode or the oxygen outside air introduction mode) to the breathing mode. In the gas supply operation, nitrogen-enriched gas is supplied to the interior space (5) by the depressurization pump (231b), increasing the interior pressure (Pi). Subsequently, in breathing mode, the depressurization pump (231b) stops. Therefore, in breathing mode, the first time (Δt1) until the interior pressure (Pi) decreases from the first pressure (P1) to the second pressure (P2) can be measured, and furthermore, the actual volume (Vs) can be determined.

[0174] As shown in Figure 19(c), the controller (110) performs a second estimation operation after switching from the breathing mode described above to the outside air introduction operation (more precisely, the outside air introduction mode). At the start of the outside air introduction operation, outside air is supplied to the interior space (5) by the pressurizing pump (231a), increasing the internal pressure (Pi). Therefore, at the start of the outside air introduction operation, the first time (Δt1) until the internal pressure (Pi) increases from the first pressure (P1) to the second pressure (P2) can be measured, and furthermore, the actual volume (Vs) can be determined.

[0175] As shown in Figure 19(d), the controller (110) performs a second estimation operation after switching from the breathing mode described above to a gas supply operation (more precisely, the 5% oxygen mode or the oxygen outside air introduction mode). At the start of the gas supply operation, nitrogen-enriched gas is supplied to the interior space (5) by the depressurization pump (231b), increasing the interior pressure (Pi). Therefore, at the start of the gas supply operation, the first time (Δt1) until the interior pressure (Pi) increases from the first pressure (P1) to the second pressure (P2) can be measured, and furthermore, the actual volume (Vs) can be determined.

[0176] (9) Control after estimating the actual volume The controller (110) estimates the actual volume (Vs) through estimation operation and then performs at least one of the following controls. Details of these controls are described below.

[0177] (9-1) Recalculation of Cv value using actual volume The controller (110) recalculates the airtightness index of the transport container (1) based on the actual volume (Vs) obtained by the estimation operation and an index showing the rate of change of the internal pressure (Pi) when the internal pressure (Pi) changes. Specifically, as shown in Figure 20, in step ST61, the controller (110) obtains the Cv value using the airtightness measurement mode described above. Next, in step ST62, the controller (110) estimates the actual volume (Vs) of the internal space (5) using the estimation operation described above. Next, in step ST63, the controller (110) obtains the Cv value again based on the actual volume (Vs) estimated in step ST62. Specifically, in step ST63, the controller (110) executes either the first airtightness measurement mode using the depressurization method or the second airtightness measurement mode using the pressure boosting method. The first and second airtightness measurement modes require V1, i.e., the actual volume (Vs) of the internal space (5), as a parameter for determining the Cv value. Therefore, by using the actual volume (Vs) obtained in step ST62, the Cv value can be determined even if the internal space (5) is not empty. The controller (110) may execute the first airtightness measurement mode at the timings shown in (a) and (b) of Figure 19. The controller (110) may also execute the second airtightness measurement mode at the timings shown in (c) and (d) of Figure 19.

[0178] (9-2) Display of actual volume The estimation device (E) displays the actual volume (Vs) estimated by the estimation operation on the display unit (115). Specifically, as shown in Figure 21, the estimation device (E) acquires the Cv value in step ST71 and estimates the actual volume (Vs) of the storage space (5) in step ST72. Then, in step ST73, the display unit (115) displays the actual volume (Vs) estimated by the estimation operation. In this embodiment, the display unit (115) also displays the Cv value. This allows the operator to understand the current actual volume of the storage space (5) and the Cv value of the transport container (1). These parameters are useful for managing the transport container (1).

[0179] The controller (110) may transmit the estimated actual volume (Vs) to a predetermined terminal via a wireless or wired communication line. The terminal may include a server device, a personal computer, a tablet terminal, a smartphone, etc., and may have a function to display the actual volume (Vs). The estimation device (E) may constitute an estimation system including a communication line and a terminal.

[0180] (9-3) Estimation of respiratory volume The estimation device (E) estimates the respiration rate of the cargo based on the actual volume (Vs) estimated in the estimation operation. Specifically, as shown in Figure 22, the controller (110) obtains the Cv value in step ST81 and estimates the actual volume (Vs) of the storage space (5) in step ST82. Next, in step ST90, the controller (110) performs a respiration rate estimation operation to determine the respiration rate of the cargo (more precisely, fruits and vegetables and flowers) based on the actual volume (Vs). The respiration rate estimation operation includes a first respiration rate estimation operation and a second respiration rate estimation operation. In the first respiration rate estimation operation, the estimation device (E) estimates the oxygen consumption rate (Ro) as the respiration rate of fruits and vegetables and flowers. In the second respiration rate estimation operation, the estimation device (E) estimates the carbon dioxide generation rate (Rc) as the respiration rate of fruits and vegetables and flowers.

[0181] (9-3-1) First respiratory volume estimation operation In the first respiratory volume estimation operation shown in Figure 23, in step ST91, the controller (110) causes the gas supply operation to be performed. In step ST91, the controller (110) causes nitrogen-enriched gas with adjusted oxygen concentration to be supplied to the chamber space (5) by the gas supply operation. The gas supply operation may be performed in an 8% oxygen concentration mode or in a 5% oxygen concentration mode.

[0182] Next, in step ST92, the controller (110) measures the oxygen concentration (first oxygen concentration (Ca)) at the fifth time point (t5) in the interior space (5) and the oxygen concentration (second oxygen concentration (Cb)) at the sixth time point (t6) in the interior space (5) using the oxygen sensor (161).

[0183] Next, in step ST93, the controller (110) estimates the oxygen consumption rate (Ro) using equation (4) in Figure 23. Here, equation (4) is the theoretical formula for the second oxygen concentration (Cb) at the sixth time step (t6). In equation (4), Vs is the actual volume of the internal space (5), and corresponds to the actual volume of internal air present in the internal space (5). Δt3 is the time (third hour) between the fifth time step (t5) and the sixth time step (t6). Qi is the inflow rate of nitrogen-enriched gas supplied to the internal space (5). Co is the oxygen concentration of the nitrogen-enriched gas supplied to the internal space (5), which is 8% in the 8% oxygen concentration mode and 5% in the 5% oxygen concentration mode. By substituting each parameter into equation (4), the controller (110) can determine the oxygen consumption rate (Ro).

[0184] In step ST91, the controller (110) may perform an outside air introduction operation instead of a gas supply operation. In this case, the inflow rate (Qi) in equation (4) becomes the flow rate of outside air supplied to the interior space (5), and the supplied oxygen concentration (Co) in equation (4) becomes the oxygen concentration of the outside air (approximately 21%). If outside air flows into the interior space (5) from another route, the flow rate of this incoming air and its oxygen concentration (21%) may be added to the numerator of equation (4), and the flow rate of this incoming air may be added to the denominator. The controller (110) can estimate this air flow rate based on the Cv value or the first index.

[0185] (9-3-2) Second respiratory volume estimation operation In the second respiratory volume estimation operation shown in Figure 24, in step ST101, the controller (110) causes the gas supply operation to be performed. In step ST101, the controller (110) causes nitrogen-enriched gas with adjusted oxygen concentration to be supplied to the chamber space (5) by the gas supply operation. The gas supply operation may be in 8% oxygen concentration mode or 5% oxygen concentration mode.

[0186] Next, in step ST102, the controller (110) measures the carbon dioxide concentration (first carbon dioxide concentration (Cc)) at the seventh time point (t7) in the interior space (5) and the carbon dioxide concentration (second carbon dioxide concentration (Cd)) at the eighth time point (t8) in the interior space (5) using the carbon dioxide sensor (162).

[0187] Next, in step ST103, the controller (110) estimates the carbon dioxide generation rate (Rc) using equation (5) in Figure 24. Here, equation (5) is the theoretical formula for the second carbon dioxide concentration (Cd) at the eighth time point (t8). In equation (5), Δt4 is the time (fourth hour) between the seventh time point (t7) and the eighth time point (t8). In the numerator of equation (5), the carbon dioxide supplied to the interior space (5) by the supply of nitrogen-enriched gas is ignored because the carbon dioxide concentration is extremely low, approximately 300 ppm. By substituting each parameter into equation (5), the controller (110) can determine the carbon dioxide generation rate (Rc).

[0188] In step ST101, the controller (110) may perform an outside air introduction operation instead of a gas supply operation. In this case as well, in equation (4), carbon dioxide in the outside air supplied to the interior space (5) can be ignored. If outside air flows into the interior space (5) from another route, the flow rate of this incoming air may be added to the denominator of equation (5). The controller (110) can estimate this air flow rate based on the Cv value or the first index.

[0189] (10) Characteristics of the embodiment (10-1) The estimation device (E) includes an air pump (231) as a pressure adjustment unit for changing the pressure in the internal space (5) of the transport container (1), a differential pressure sensor (170) as a pressure detection unit for determining the internal pressure (Pi) of the internal space (5), and a controller (110). When the internal pressure (Pi) changes, the controller (110) performs an estimation operation to estimate the actual volume (Vs) of the internal space (5) based on a first index indicating the rate of change of the internal pressure (Pi).

[0190] This estimation process allows for the automatic estimation of the actual volume (Vs) of the storage space (5). The actual volume (Vs) is useful for managing the transport container (1), the air composition control device (90), or the transport refrigeration device (10). For example, the actual volume (Vs) can be displayed, the Cv value can be recalculated based on the actual volume (Vs), and the respiration rate of fruits, vegetables, and flowers can be estimated.

[0191] (10-2) The controller (110) performs a first estimation operation to estimate the actual volume (Vs) of the internal space (5) based on a first indicator showing the rate of increase in the internal pressure (Pi). Thus, the actual volume (Vs) can be estimated when the internal pressure is increased by the air pump (231).

[0192] The controller (110) performs a second estimation operation to estimate the actual volume (Vs) of the internal space (5) based on a first indicator showing the rate of decrease in the internal pressure (Pi). Thus, the actual volume (Vs) can be estimated when the internal pressure is increased by the air pump (231) and then decreased.

[0193] (10-3) The controller (110) estimates the actual volume (Vs) of the transport container (1) based on the airtightness index and a first index during the estimation operation. This allows the controller to estimate the actual volume (Vs) while individually considering air leakage from the transport container (1), even when there is variation in the airtightness of the transport container (1). Therefore, the actual volume (Vs) of the internal space (5) can be estimated with high accuracy.

[0194] Specifically, the controller (110) performs a first airtightness measurement mode to determine the airtightness index based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and an index indicating the rate of decrease in internal pressure (Pi) when the internal pressure (Pi) decreases. This is because the external pressure (Po), internal pressure (Pi), and the rate of decrease in internal pressure are parameters that affect the airtightness index of the transport container (1). The first airtightness measurement mode has the advantage that the inflow flow rate (Qi) is zero, so there is no need to measure the inflow flow rate (Qi).

[0195] The controller (110) executes a second airtightness measurement mode to determine the airtightness index based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and an index indicating the rate of increase of the internal pressure (Pi) when the internal pressure (Pi) increases. This is because the external pressure (Po), internal pressure (Pi), and the rate of increase of the internal pressure are parameters that affect the airtightness index of the transport container (1). The second airtightness measurement mode has the advantage of shorter measurement time compared to the first airtightness measurement mode because it determines the rate of increase of the internal pressure (Pi) associated with the operation of the air pump (231).

[0196] The controller (110) executes the first airtightness measurement mode or the second airtightness measurement mode when the storage space (5) is empty. The first airtightness measurement mode and the second airtightness measurement mode require V1, that is, the actual volume (Vs), in equations (2) and (3), and when the storage space (5) is empty, the actual volume (Vs) can be considered as the total volume of the storage space (5).

[0197] (10-4) The pressure adjustment unit (231) is an air conveying unit that supplies air to the interior space (5). The controller (110) performs a third airtightness measurement mode to determine the airtightness index based on the interior pressure (Pi), the external pressure (Po) of the external space (6), and the inflow rate of air supplied to the interior space (5) during a period when the interior pressure (Pi) is constant while the air pump (231) is operating. This is because if the interior pressure (Pi) is constant, these parameters will affect the airtightness index.

[0198] The controller (110) executes the third airtightness measurement mode when there is cargo in the storage space (5). The third airtightness measurement mode is an airtightness index measured when the storage pressure (Pi) is constant and is not affected by the actual volume of the storage space (5). Therefore, even when there is cargo in the storage space (5), the Cv value can be accurately estimated without using the actual volume (Vs).

[0199] (10-5) In its estimation operation, the controller (110) estimates the actual volume (Vs) based on the external pressure (Po) of the external space (6) and the first indicator. Therefore, even if the airtightness of the transport container (1) is insufficient and air leaks between the external space (6) and the internal space (5), the controller can estimate the actual volume (Vs) while individually considering the air leakage from the transport container (1).

[0200] (10-6) The pressure detection unit includes a differential pressure sensor (170) that detects the differential pressure between the outside air and the inside air. The controller (110) determines the inside pressure (Pi) from the differential pressure (ΔP) of the differential pressure sensor (170) and atmospheric pressure (i.e., outside pressure). This simplifies the configuration of the pressure detection unit.

[0201] The pressure regulating unit is comprised of an air pump (231). This simplifies the configuration of the air composition regulating device (90).

[0202] (10-7) The controller (110) estimates the oxygen consumption rate (Ro) of fruits, vegetables, or flowers in the storage space (5) based on the actual volume (Vs) of the storage space (5) and the oxygen concentration of the air inside the storage space (5). Specifically, the controller (110) estimates the oxygen consumption rate (Ro) based on the actual volume (Vs) of the storage space (5), the change in oxygen concentration in the air inside the storage space, and the change in the volume of air inside the storage space (5). Therefore, the oxygen consumption rate (Ro) can be used for cargo management, etc.

[0203] The controller (110) estimates the carbon dioxide generation rate (Rc) of fruits, vegetables, or flowers in the storage space (5) based on the actual volume (Vs) of the storage space (5) and the carbon dioxide concentration of the air inside the storage space (5). Specifically, the controller (110) estimates the carbon dioxide generation rate (Rc) based on the actual volume (Vs) of the storage space (5), the change in carbon dioxide concentration in the air inside the storage space, and the change in the volume of air inside the storage space (5). Therefore, the carbon dioxide generation rate (Rc) can be used for cargo management, etc.

[0204] (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.

[0205] (11-1) Modification 1: Pressure sensing unit The pressure sensing unit of the embodiment may have the following configuration.

[0206] As shown in Figure 25, the main body case (171) of the differential pressure sensor (170), which is the pressure sensing 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 the 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 controller (110) takes the external pressure as atmospheric pressure and calculates the internal pressure (Pi) based on the differential pressure (ΔP).

[0207] Alternatively, the pressure detection unit may have an internal pressure sensor and an external pressure sensor. The internal pressure sensor and the external pressure sensor 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 controller (110) calculates the differential pressure (ΔP) by subtracting the external pressure from the internal pressure (Pi).

[0208] Alternatively, the pressure detection unit 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 controller (110) takes the external pressure as atmospheric pressure and calculates the differential pressure (ΔP) by subtracting the atmospheric pressure from the internal pressure (Pi).

[0209] (11-2) Modification 2: Pressure adjustment section The air pump (231) in this embodiment is an example of a pressure regulating unit. The pressure regulating unit may have the following configuration.

[0210] The pressure adjustment unit may be a depressurizing pump that reduces the pressure inside the chamber (5). By reducing the internal pressure (Pi) with the depressurizing pump, the actual volume (Vs) of the internal chamber (5) can be estimated by the depressurizing method. In addition, the Cv value can be determined by the depressurizing method.

[0211] The pressure adjustment unit may be a ventilation device that introduces outside air into the interior space (5). The ventilation device has an air intake port for supplying outside air into the interior space (5) and an air intake fan. By supplying outside air into the interior space (5) with the air intake fan, the internal pressure (Pi) can be increased. This makes it possible to estimate the actual volume (Vs) of the interior space (5) by the pressure boosting method, or to determine the Cv value by the pressure boosting method.

[0212] The pressure adjustment unit may be a ventilation device that discharges the internal air into the external space (6). The ventilation device has an exhaust port for exhausting the internal air into the external space (6) and an exhaust fan. By exhausting the internal air into the external space (6) with the exhaust fan, the internal pressure (Pi) can be reduced. This makes it possible to estimate the actual volume (Vs) of the internal space (5) by the depressurization method, or to determine the Cv value by the depressurization method.

[0213] The pressure regulating unit may be a heating unit that heats the air inside the chamber. The heating unit may be the internal heat exchanger (15) of the embodiment, or it may be another device such as a heater. When the air inside the chamber is heated, the internal pressure (Pi) increases. This makes it possible to estimate the actual volume (Vs) of the internal space (5) by the pressure boosting method, or to determine the Cv value by the pressure boosting method.

[0214] The pressure adjustment unit may also be a cooling unit that cools the air inside the chamber. The cooling unit may be the internal heat exchanger (15) of the embodiment, or it may be another device such as a Peltier element. When the air inside the chamber is cooled, the internal pressure (Pi) decreases. This makes it possible to estimate the actual volume (Vs) of the internal space (5) by the depressurization method, or to determine the Cv value by the depressurization method.

[0215] (11-3) Modification 3: Airtightness measurement mode and estimation of actual volume The controller (110) of the estimation device (E) may perform only one or two of the three airtightness measurement modes described above. Even with this configuration, the estimation device (E) can estimate the actual volume (Vs) based on the Cv value obtained in one of the airtightness measurement modes.

[0216] Alternatively, the estimation device (E) does not need to be able to perform airtightness measurement mode. For example, the user may input a Cv value measured by another measuring instrument into the controller (110), and the estimation device (E) may estimate the actual volume (Vs) based on the input Cv value. The estimation device (E) may also estimate the actual volume (Vs) based on the Cv value obtained at the time of shipment of the transport container (1).

[0217] The controller (110) of the estimation device (E) may perform only one of the first estimation operation or the second estimation operation. The controller (110) of the estimation device (E) may estimate the actual volume (Vs) without using the Cv value. The memory device (112) of the controller (110) has data for estimating the actual volume (Vs), and the estimation device (E) may estimate the actual volume (Vs) based on this data and the first index. This data may be, for example, a relational expression or data table showing the relationship between the first time (Δt1) and the actual volume (Vs) obtained under predetermined environmental conditions. Since the rate of pressure change is correlated with the actual volume (Vs) of the internal space (5), the actual volume (Vs) can be estimated using such a relational expression or data table.

[0218] The controller (110) may use the rate of increase or decrease in the internal pressure (Pi) directly as the first indicator for determining the actual volume (Vs), rather than the first time (Δt1).

[0219] The controller (110) does not necessarily have to use the detected value of the internal air temperature (Tr) to determine the actual volume (Vs). The user may initiate the estimation operation when the internal air temperature (Tr) is at a predetermined temperature.

[0220] (12) Other embodiments 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.

[0221] 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.

[0222] The estimation device (E) may be provided in a transport refrigeration system (10) that does not have an air composition adjustment device (90). 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 controller (110).

[0223] The controller (110) of the estimation device (E) may be installed in the transport refrigeration device (10), server device, user-operated terminal device, etc. The controller (110) may be composed of two or more physically separated control elements.

[0224] 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.

[0225] 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]

[0226] As described above, this disclosure is useful for estimation devices, air composition adjustment devices, and transport refrigeration devices. [Explanation of Symbols]

[0227] 1. Shipping container 5. Interior space 6 Outside space 10 Transport refrigeration equipment 11 Refrigerant Circuit 90 Air composition adjustment device 95 Air Processing Unit 110 Controller 170 Differential pressure sensor (pressure detection unit) 231 Air pump (pressure regulating unit) E estimation device Pi internal pressure Po external pressure Qi inflow flow rate Vs Actual Volume ΔP Differential pressure

Claims

1. A pressure adjustment unit (231) that changes the pressure in the internal space (5) of the transport container (1), A pressure detection unit (170) for determining the internal pressure (Pi) of the internal space (5) of the storage chamber, An estimation device comprising a controller (110) that performs an estimation operation to estimate the actual volume of the internal space (5) based on a first index indicating the rate of change of the internal pressure (Pi) when the internal pressure (Pi) changes.

2. The first indicator is an indicator that shows the rate of increase in the internal pressure (Pi) of the chamber. The estimation device according to claim 1.

3. The first indicator is an indicator that shows the rate of decrease in the internal pressure (Pi) of the chamber. The estimation device according to claim 1.

4. In the estimation operation, the controller (110) estimates the actual volume based on an airtightness index indicating the airtightness of the transport container (1) and the first index. The estimation device according to claim 1.

5. The controller (110) executes a first airtightness measurement mode to determine the airtightness index based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and an index indicating the rate of decrease in the internal pressure (Pi) when the internal pressure (Pi) decreases. The estimation device according to claim 4.

6. The controller (110) executes a second airtightness measurement mode to determine the airtightness index based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and an index indicating the rate of increase of the internal pressure (Pi) when the internal pressure (Pi) increases. The estimation device according to claim 4.

7. The controller (110) executes the first airtightness measurement mode or the second airtightness measurement mode when the internal storage space (5) is empty. The estimation device according to claim 5 or 6.

8. The pressure adjustment unit is an air transport unit (231) that supplies air to the internal space (5) of the chamber, The controller (110) executes a third airtightness measurement mode to determine the airtightness index based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and the inflow rate of air supplied to the internal space (5), during a period when the internal pressure (Pi) of the air transport unit (231) is constant during operation. The estimation device according to claim 4.

9. The controller (110) executes the third airtightness measurement mode when there is cargo in the storage space (5). The estimation device according to claim 8.

10. In the estimation operation, the controller (110) estimates the actual volume based on the internal pressure (Pi), the external pressure (Po) of the external space (6), and the first indicator. An estimation device according to any one of claims 1 to 6.

11. The pressure detection unit includes a differential pressure sensor (170) that detects the differential pressure between the outside air and the inside air of the storage unit. The estimation device according to claim 10.

12. The estimation device (E) according to any one of claims 1 to 6, The system includes an air processing unit (95) that adjusts the composition of the air in the internal space (5) of the chamber. Air composition adjustment device.

13. The system is further equipped with an air pump (231) that supplies air to the interior space (5), The pressure adjustment unit (231) is comprised of the air pump (231). The air composition adjustment device according to claim 12.

14. The controller (110) estimates the respiration rate of fruits, vegetables, or flowers in the storage space (5) based on the actual volume of the storage space (5) and the oxygen concentration or carbon dioxide concentration of the air inside the storage space (5). The air composition adjustment device according to claim 12.

15. An estimation device (E) according to any one of claims 1 to 6, The system includes a refrigerant circuit (11) for cooling the interior space of the storage unit. Refrigeration equipment for transportation.

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