Container refrigeration equipment

Abstract

To detect a refrigerant leaking into the container relatively quickly.SOLUTION: A freezer for a container includes: a first carrier (30) which circulates air in a container (1) between a housing space (3) and an air passage (19); a heat exchanger (29) disposed in the air passage (19); a detection unit (110a) which is disposed below the heat exchanger (29) and detects a refrigerant leaking into the container (1); and casings (50, 111) which house the detection unit (110a). The casings (50, 111) have a first opening (51) which allows communication between the detection unit (110a) and the air passage (19). The first opening (51) is open in a horizontal direction or the lower side than the horizontal direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to container refrigeration systems. [Background technology]

[0002] The container refrigeration system disclosed in Patent Document 1 is equipped with a refrigerant sensor that detects refrigerant leaks inside the container. The refrigerant sensor is located downstream of the heat exchanger in the air flow, so that the air that has passed through the heat exchanger passes through the refrigerant sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-101327 A Summary of the Invention [Problem to be solved by the invention]

[0004] Even if refrigerant leaks into the air, the fan transports the air containing the refrigerant, allowing the refrigerant sensor to detect the refrigerant in the air relatively quickly. However, even if the refrigerant sensor is located downstream of the heat exchanger in the air flow, the air inside the refrigerator is not circulated while the fan is stopped, so if a refrigerant leak occurs at such a time, it may take some time for the refrigerant sensor to detect the leaked refrigerant.

[0005] An object of the present disclosure is to relatively quickly detect refrigerant leaking inside a container. [Means for solving the problem]

[0006] The first aspect is A container refrigeration unit provided in a container (1) having a refrigerant circuit (R) that performs a refrigeration cycle, the container (1) having an interior partitioned into a storage space (3) and an air passage (19) communicating with the storage space (3), a first conveyor (30) for circulating the air inside the container (1) between the storage space (3) and the air passage (19); a heat exchanger (29) disposed in the air passage (19); a detector (110a) disposed below the heat exchanger (29) and configured to detect refrigerant leaking into the container (1); a casing (50, 111) that houses the detection part (110a), The casing (50, 111) has a first opening (51) that connects the detection portion (110a) to the air passage (19), The first opening (51) opens in a horizontal direction or downward from the horizontal direction. This is a container refrigeration unit.

[0007] According to the first aspect, the first opening (51) opens horizontally or downwardly from the horizontal direction, and therefore, when the first conveyor (30) is stopped, the leaked refrigerant accumulated in the lower part of the interior of the container (1) diffuses upward, and the refrigerant easily enters the first opening (51). This reduces the time required for the detection unit (110a) to detect the leaked refrigerant inside the container (1), and allows the leaked refrigerant to be detected relatively quickly.

[0008] The second aspect is A container refrigeration unit provided in a container (1) having a refrigerant circuit (R) that performs a refrigeration cycle, the container (1) having an interior partitioned into a storage space (3) and an air passage (19) communicating with the storage space (3), a first conveyor (30) for circulating the air inside the container (1) between the storage space (3) and the air passage (19); a heat exchanger (29) disposed in the air passage (19); a detector (110a) disposed below the heat exchanger (29) and configured to detect refrigerant leaking into the container (1); a casing (50, 111) that houses the detection part (110a), The air passage (19) is formed by the first conveyor (30) so that air flows from above to below, The casing (50, 111) has a first opening (51) that connects the detection portion (110a) to the air passage (19), The first opening (51) opens in a direction perpendicular to the air flow in the air passage (19) or toward the downstream side of the air flow. This is a container refrigeration unit.

[0009] When the pressure acting on the detection element (110a) due to the air flowing through the air passage (19) increases, the detection element (110a) is more likely to erroneously detect the presence of refrigerant. In contrast, in the second aspect, the first opening (51) is opened in a direction perpendicular to the air flow in the air passage (19), thereby suppressing the pressure acting on the first opening (51). This makes it possible to suppress erroneous detection of the presence of refrigerant.

[0010] The third aspect is the first or second aspect, The air conditioner further includes a pressure reducing section (120) disposed in the air passage (19) for reducing the pressure acting on the first opening (51) due to the air conveyed by the first conveyer (30).

[0011] In the third aspect, the pressure reducing portion (120) reduces the pressure acting on the detecting portion (110a), thereby making it possible to prevent erroneous detection of the refrigerant.

[0012] A fourth aspect is any one of the first to third aspects, the casing (50, 111) further includes a second opening (52) that connects the detection portion (110a) to the air passage (19); The second opening (52) opens toward the upstream side of the air flow in the air passage (19).

[0013] In the fourth aspect, while the first conveyor (30) is operating, dynamic pressure due to the air flow can be utilized to facilitate the intake of air through the second opening (52). Furthermore, while the first conveyor (30) is stopped, natural diffusion of air can be utilized to facilitate the intake of air through the first opening (51). In this way, the time from when a refrigerant leak occurs to when the refrigerant leak is detected can be shortened both while the first conveyor (30) is operating and while it is stopped.

[0014] The fifth aspect is the fourth aspect, The first conveyor (30) is disposed in the air passage (19), The first opening (51) and the second opening (52) are disposed below the first conveyor (30).

[0015] In the fifth aspect, by being disposed below the first conveyor (30) in the air passage (19), the air pressure acting on the second opening (52) can be utilized to promote the circulation of air in the casing (50, 111) flowing in through the second opening (52).

[0016] A sixth aspect is the fourth or fifth aspect, The casing (50, 111) has a receiving portion (53) between the second opening (52) and the detection portion (110a) for receiving water that has flowed from the air passage (19) into the second opening (52).

[0017] In the sixth aspect, the receiving portion (53) can prevent water that has flowed into the second opening (52) together with air from splashing into the casing (50, 111). This can prevent water from adhering to the detecting portion (110a), thereby preventing erroneous detection of the refrigerant and failure of the detecting portion (110a).

[0018] A seventh aspect is any one of the fourth to sixth aspects, The casing (50, 111) has an outlet (54) between the second opening (52) and the detection part (110a) for discharging water that has flowed from the air passage (19) into the second opening (52) to the outside.

[0019] The water that has flowed into the second opening (52) together with the air can be discharged to the outside of the casing (50, 111), thereby achieving the same effect as in the sixth aspect.

[0020] An eighth aspect is any one of the fourth to seventh aspects, The casing (50, 111) has a cylindrical portion (62) in which the second opening (52) is formed and which communicates with the detecting portion (110a).

[0021] In the eighth aspect, the dynamic pressure of the air passing through the cylindrical portion (62) and flowing into the casing (50, 111) is reduced, thereby decreasing the wind speed, thereby suppressing the pressure of the air acting on the detection portion (110a) and preventing erroneous detection of the refrigerant.

[0022] A ninth aspect is the eighth aspect, The cylindrical portion (62) has a first cylindrical portion (62a) and a second cylindrical portion (62b) formed in this order toward the air passage (19), The second cylindrical portion (62b) is formed so that the cross-sectional area of ​​the flow path is larger than the cross-sectional area of ​​the flow path of the first cylindrical portion (62a), The second opening (52) is formed in the second cylindrical portion (62b).

[0023] In the ninth aspect, a pressure loss occurs when air flows from the second cylindrical portion (62b) into the first cylindrical portion (62a), thereby reducing the total pressure, thereby reducing the dynamic pressure of the air flowing from the first cylindrical portion (62a) into the casing (50, 111), thereby reducing the wind speed.

[0024] A tenth aspect is any one of the fourth to ninth aspects, The opening surface of the second opening (52) is formed to be inclined with respect to the air flow in the air passage (19), and includes a suppression portion (55) that suppresses the inflow of foreign matter contained in the air in the air passage (19).

[0025] In the tenth aspect, the opening area of ​​the second opening (52) can be increased, thereby allowing a large amount of air to be taken in. Furthermore, the suppression part (55) can prevent foreign matter contained in the air from reaching the detection part (110a), thereby preventing false detection of the refrigerant and failure of the detection part (110a).

[0026] An eleventh aspect is any one of the first to tenth aspects, The casing (50, 111) is provided with a second conveyor (130) for sucking air from the air passage (19) into the first opening (51).

[0027] In the eleventh aspect, the second conveyer (130) can forcefully draw air into the first opening (51), thereby conveying the refrigerant-containing air accumulating at the bottom of the air passage (19) to the refrigerant sensor (110).

[0028] A twelfth aspect is the eleventh aspect, The first conveyor (30) has a first electric motor (30b) that drives the first conveyor (30), The second conveyor (130) has a second motor (130a) that drives the second conveyor (130), The first electric motor (30b) and the second electric motor (130a) are supplied with electric power from different power sources.

[0029] In the twelfth aspect, by connecting the second conveyor (130) and the first conveyor (30) to different power sources, the second conveyor (130) can be operated even when the first conveyor (30) is stopped, making it possible to detect refrigerant leakage.

[0030] A thirteenth aspect is the eleventh or twelfth aspect, The second conveyor (130) draws air at a height of 1 m or less from the bottom surface of the air passage (19) to the first opening (51).

[0031] In the thirteenth aspect, it is possible to detect refrigerant that accumulates at a height of 1 m or less from the bottom surface of the air passage (19).

[0032] A fourteenth aspect is any one of the eleventh to thirteenth aspects, the casing (50, 111) has a third opening (73) through which air sucked into the first opening (51) is blown out into the air passage (19); The third opening (73) is located at the same height as or lower than the first opening (51).

[0033] During operation of the first conveyor (30), the pressure generated at the first opening (51) is equal to or higher than the pressure generated at the third opening (73) downstream of the air flow, so that the second conveyor (130) sucks air through the first opening (51), thereby reducing the operating load of the second conveyor (130).

[0034] A fifteenth aspect is any one of the first to fourteenth aspects, The container (1) has a wall (16a) that separates the external space (5) from the air passage (19), The casing (50, 111) is provided on the wall (16a).

[0035] In the fourteenth aspect, maintenance of the detection unit (110a) can be performed from outside the container (1) without entering the container (1). [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a perspective view of a container refrigeration unit according to an embodiment, as seen from the front. [Figure 2] FIG. 2 is a vertical cross-sectional view of a container refrigeration unit. [Figure 3] FIG. 3 is a piping diagram of a container refrigeration unit. [Figure 4] FIG. 4 is a block diagram showing the relationship between the control unit of the container refrigeration unit and other devices. [Figure 5] FIG. 5 is an enlarged view of the area enclosed by the dashed line in FIG. [Figure 6]FIG. 6 is a vertical cross-sectional view corresponding to FIG. 5 of a container refrigeration unit according to the first modification. [Figure 7] FIG. 7 is a vertical cross-sectional view corresponding to FIG. 2 of a container refrigeration unit according to Modification 2. As shown in FIG. [Figure 8] FIG. 8 is an enlarged view of the area enclosed by the dashed line in FIG. [Figure 9] FIG. 9 is a perspective view of a vertical cross section of a sensor casing according to the second modification. [Figure 10] FIG. 10 is a vertical cross-sectional view corresponding to FIG. 2 of a container refrigeration unit according to Modification 3. As shown in FIG. [Figure 11] FIG. 11 is a perspective view of a sensor casing according to the third modification. [Figure 12] 12 is an enlarged view of the portion surrounded by the dashed line in FIG. 10. (A) is a view showing a cross section taken along the line AA in FIG. 11. (B) is a view showing a cross section taken along the line BB in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses. Furthermore, each configuration of the embodiments, modifications, other examples, etc. described below can be combined or partially substituted within the scope of the present invention.

[0038] (1) Overall configuration of the container The container refrigeration unit (10) is applied to a container (1). The overall configuration of the container (1) of this embodiment will be described with reference to Figures 1 to 3. In the following description, terms such as "front," "rear," "left," "right," "upper," and "lower" refer to the directions indicated by the arrows in Figure 1.

[0039] The container (1) is used for marine transportation. The container (1) is a refrigerated container that cools the air inside the container (1). The container (1) has a container body (2) and a container refrigeration unit (10). As shown in FIG. 2, the interior of the container body (2) is divided into a storage space (3) and an air passage (19) that communicates with the storage space (3). The storage space (3) stores objects such as food and plants. The container refrigeration unit (10) cools the storage space (3). A front opening (4) is formed in the front of the container body (2). The container refrigeration unit (10) is attached to the container body (2) so as to close the front opening (4) of the container body (2).

[0040] (2) Container refrigeration equipment The container refrigeration unit (10) has a container casing (11). The container casing (11) forms a lid for the front opening (4) of the container body (2). The container casing (11) has a casing body (12) and a partition plate (13). The casing body (12) separates the storage space (3) from an external space (5) that is the external space of the container body (2). The partition plate (13) is located on the back side (rear side) of the container casing (11).

[0041] The container refrigeration system (10) includes a refrigerant circuit (R) that performs a refrigeration cycle. The container refrigeration system (10) includes, as external components, a compressor (25), an external heat exchanger (26), and an external fan (27). The container refrigeration system (10) includes, as internal components, an internal heat exchanger (29) and an internal fan (30).

[0042] (2-1) Casing body As shown in FIG. 2, the casing body (12) has a flat plate portion (12a) and a recessed portion (12b). The flat plate portion (12a) is formed on the upper part of the casing body (12) so as to be substantially flush with the front opening (4) of the container casing (11). As shown in FIG. 1, the flat plate portion (12a) is provided with an inspection window (22) and a ventilation device (40). The inspection window (22) is located on the right side of the flat plate portion (12a). The ventilation device (40) is located on the left side of the flat plate portion (12a). The inspection window (22) is a transparent window through which the inside of the casing body (12) can be seen. The ventilation device (40) ventilates the storage space (3).

[0043] The recess (12b) is formed in the lower part of the container casing (11). The recess (12b) is recessed rearward from the lower end of the flat plate portion (12a). An external storage space (14) is formed in front of the recess (12b). An internal storage space (15) is formed above the recess (12b) and between the flat plate portion (12a) and the partition plate (13). The lower end of the recess (12b) forms a bottom plate (12c). The bottom plate (12c) extends to both the left and right ends of the casing body (12).

[0044] The casing body (12) is formed by stacking an external casing (16), a heat insulating layer (17), and an internal casing (18) in the thickness direction (front-rear direction). The external casing (16) faces the external space (5). The internal casing (18) faces the interior of the refrigerator. As described above, the recess (12b) has a side wall (16a) of the external casing (16) and a side wall of the internal casing (18) that extend in the vertical direction. The side wall (16a) of the external casing (16) that extends in the vertical direction is an example of a wall portion (16a) that separates the external space (5) and the air passage (19). The heat insulating layer (17) is provided between the external casing (16) and the internal casing (18). The external casing (16) is made of aluminum. The inner casing (18) is made of fiber reinforced plastic (FRP), and the heat insulating layer (17) is made of foamed resin.

[0045] (2-2) Partition plate and air passage As shown in FIG. 2 , the partition plate (13) is a plate-like member located behind the recessed portion (12b). The partition plate (13) extends in the vertical direction so as to be spaced a predetermined distance from the rear surface of the recessed portion (12b). An air passage (19) through which air flows inside the container is formed between the casing body (12) and the partition plate (13). An inlet (20) is formed between the upper end of the partition plate (13) and the upper wall (2a) of the container body (2). The inlet (20) connects the storage space (3) to the inlet end of the air passage (19). An outlet (21) is formed between the lower end of the partition plate (13) and the lower wall (2b) of the container body (2). The outlet (21) connects the storage space (3) to the outlet end of the air passage (19). Air flows in the vertical direction in the air passage (19). Specifically, air flows in the vertical direction in the air passage (19).

[0046] (2-3) External space components The external storage space (14) is provided with a compressor (25), an external heat exchanger (26), and an external fan (27). The compressor (25) is installed on the bottom plate (12c) of the container casing (11). The compressor (25) is disposed near the bottom of the external storage space (14). The compressor (25) is disposed near the right of the external storage space (14).

[0047] The external fan (27) is located near the upper part of the external storage space (14). The external fan (27) has an external fan body (27a) and an external fan motor (27b). The external fan body (27a) is a propeller fan. The external fan motor (27b) drives the external fan body (27a) when energized. As shown in FIG. 2, an external passage (28) through which outside air flows is formed behind the external fan (27).

[0048] The external heat exchanger (26) is provided in the external storage space (14) at a height position between the external fan (27) and the compressor (25). The external heat exchanger (26) is located in the external passage (28). The external heat exchanger (26) is a fin-and-tube heat exchanger.

[0049] (2-4) Components of the interior space An internal heat exchanger (29) and an internal fan (30) are provided in the air passage (19). Specifically, the internal heat exchanger (29) and the internal fan (30) are provided in the internal storage space (15), which is part of the air passage (19). The internal heat exchanger (29) is supported by the container casing (11) so as to span the casing body (12) and the partition plate (13). The internal heat exchanger (29) is a fin-and-tube heat exchanger. The internal heat exchanger (29) is an example of a heat exchanger (29).

[0050] The internal fan (30) circulates air inside the container (1) between the storage space (3) and the air passage (19). The internal fan (30) has an internal fan body (30a) and an internal fan motor (30b). The internal fan body (30a) is a propeller fan. The internal fan motor (30b) drives the internal fan body (30a) when energized. The internal fan motor (30b) is an example of a first electric motor (30b).

[0051] (2-5) Refrigerant circuit As shown in Figure 3, the container refrigeration unit (10) has a refrigerant circuit (R). The refrigerant circuit (R) is filled with a refrigerant. The refrigerant circuit (R) performs a vapor compression refrigeration cycle by circulating the refrigerant.

[0052] The refrigerant in the refrigerant circuit (R) has a density greater than that of air. In this embodiment, 2,3,3,3 tetrafluoropropene (hereinafter sometimes referred to as R1234yf refrigerant or R1234yf) is used as the refrigerant. The refrigerant may be difluoromethane (R32) or 1,3,3,3 tetrafluoropropene (R1234ze). The refrigerant may be a single refrigerant or a mixed refrigerant containing other refrigerants. The mixed refrigerant may be a refrigerant consisting of 2,3,3,3 tetrafluoropropene (R1234yf) and difluoromethane (R32). The mixed refrigerant may be a refrigerant (R454C) consisting of 78.5% by weight of 2,3,3,3 tetrafluoropropene (R1234yf) and 21.5% by weight of difluoromethane (R32). The refrigerant may be a flammable refrigerant. The flammable refrigerant may be a highly flammable natural refrigerant such as propane (R290), methane (R50), ethane (R170), butane (R600), or isobutane (R600a), or may be ammonia (R717).The refrigerant may also be carbon dioxide (CO2), which is a natural refrigerant.

[0053] The refrigerant circuit (R) mainly includes a compressor (25), an external heat exchanger (26), an expansion valve (31), and an internal heat exchanger (29).

[0054] The compressor (25) compresses the drawn refrigerant. The compressor (25) discharges the compressed refrigerant. A discharge pipe (32) is connected to a discharge portion of the compressor (25). A suction pipe (33) is connected to a suction portion of the compressor (25). An accumulator (34) is provided in the suction pipe (33). The accumulator (34) is a container for storing liquid refrigerant.

[0055] The external heat exchanger (26) exchanges heat between the refrigerant flowing therethrough and the external air. The gas end of the external heat exchanger (26) communicates with the discharge pipe (32). The liquid end of the external heat exchanger (26) is connected to the liquid end of the internal heat exchanger (29) via a liquid pipe (35). The external heat exchanger (26) functions as a radiator (condenser) that radiates heat from the refrigerant to the air.

[0056] The expansion valve (31) is provided in the liquid pipe (35). The expansion valve (31) reduces the pressure of high-pressure refrigerant to low-pressure refrigerant. The expansion valve (31) is an electronic expansion valve with an adjustable opening. A receiver (36) is provided in the liquid pipe (35) between the external heat exchanger (26) and the expansion valve (31). The receiver (36) is a container for storing excess refrigerant in the refrigerant circuit (R).

[0057] The internal heat exchanger (29) exchanges heat between the refrigerant flowing therethrough and the internal air. The gas end of the internal heat exchanger (29) communicates with the suction pipe (33). The internal heat exchanger (29) functions as an evaporator in which the refrigerant absorbs heat from the air.

[0058] The refrigerant circuit (R) has a bypass pipe (37). An inflow end of the bypass pipe (37) communicates with the discharge pipe (32), and an outflow end of the bypass pipe (37) communicates with the liquid pipe (35). The bypass pipe (37) sends the refrigerant discharged from the compressor (25) to the internal heat exchanger (29), bypassing the external heat exchanger (26).

[0059] The refrigerant circuit (R) is provided with a first valve (38) and a second valve (39). The first valve (38) is provided between the discharge side of the compressor (25) and the gas end of the external heat exchanger (26), and downstream of the connection portion of the bypass pipe (37). The second valve (39) is provided in the bypass pipe (37). The first valve (38) and the second valve (39) are formed by solenoid on-off valves. The first valve (38) and the second valve (39) may be flow control valves whose opening degrees are adjustable.

[0060] (2-6) Driving behavior The container refrigeration system (10) performs a cooling operation and a defrosting operation.

[0061] During the cooling operation, a refrigeration cycle is performed in which refrigerant compressed by the compressor (25) is condensed in the external heat exchanger (26), reduced in pressure by the expansion valve (31), and evaporated in the internal heat exchanger (29). Air flowing out from the storage space (3) into the air passage (19) is cooled by the internal heat exchanger (29) functioning as an evaporator. The cooled air is sent to the storage space (3) (see the arrow in FIG. 2).

[0062] During the defrosting operation, the refrigerant compressed by the compressor (25) flows through the bypass pipe (37) and then through the internal heat exchanger (29). The frost on the surface of the internal heat exchanger (29) melts due to the heat of the refrigerant flowing through the internal heat exchanger (29).

[0063] (3) Control Unit As shown in FIG. 4, the container refrigeration system (10) includes a control unit (100). The control unit (100) controls the container refrigeration system (10). The control unit (100) includes a microprocessor, an electric circuit, and an electronic circuit. The microprocessor includes a CPU (Central Processing Unit), a memory, a communication interface, an analog input / output, and a contact input / output interface. The memory stores various programs to be executed by the CPU and data used by the programs.

[0064] The control unit (100) controls the mechanical elements of the container refrigeration unit (10). As shown in FIG. 4, the target value may be a value that can be arbitrarily set by a user of the container refrigeration unit (10) via an operation unit (101). The operation unit (101) is configured with, for example, a touch panel, a remote controller, and a dip switch provided on the container refrigeration unit (10). The operation unit (101) may be a communication terminal connected to the container refrigeration unit (10) via a network. The target value does not necessarily have to be set by a user, and may be a value that is automatically determined by the control unit (100) depending on, for example, an operation mode or an operation condition.

[0065] (4) Refrigerant sensor As shown in Fig. 2, the container refrigeration unit (10) includes a refrigerant sensor (110). The refrigerant sensor (110) detects refrigerant leaked from the refrigerant circuit (R) inside the container (1). Specifically, the refrigerant sensor (110) detects refrigerant contained in air flowing through the air passage (19). Hereinafter, air containing leaked refrigerant and air not containing leaked refrigerant may be collectively referred to as air.

[0066] The refrigerant sensor (110) of this embodiment is a thermal conduction gas sensor. As shown in FIG. 5, the refrigerant sensor (110) includes a housing (111), a detection element (110a), and a detection board (110b). The housing (111) accommodates the detection element (110a) and the detection board (110b). The housing (111) will be described in detail later. The detection element (110a) is an example of a detection unit (110a). The detection element (110a) detects the thermal conductivity of a gas, such as air or refrigerant gas. In this manner, the detection element (110a) detects refrigerant leaking into the container (1). The detection board (110b) detects the difference in thermal conductivity between the air and the refrigerant detected by the detection element (110a). The greater the difference in thermal conductivity, the higher the refrigerant concentration in the detected air. The detection board (110b) outputs a predetermined signal indicating the refrigerant concentration to the control unit (100).

[0067] (4-1) Sensor casing As shown in FIG. 5, the container refrigeration system (10) of this embodiment includes a sensor casing (50) that houses a refrigerant sensor (110).

[0068] The sensor casing (50) is provided on the side wall of the external casing (16). Specifically, the sensor casing (50) is provided so as to penetrate the side wall (16a) of the external casing (16) and the side wall of the internal casing (18), which are aligned in the front-to-rear direction. The front surface of the sensor casing (50) is exposed to the external storage space (14), and the rear surface (56a) is exposed to the air passage (19). In other words, the front surface of the sensor casing (50) is exposed to the external space (5).

[0069] As shown in Fig. 2, the sensor casing (50) is disposed below the external heat exchanger (26). Preferably, the sensor casing (50) is disposed at the same height as the compressor (25) when the external casing (16) is viewed from the front. More preferably, the sensor casing (50) is disposed at a height near the bottom plate (12c) when the external casing (16) is viewed from the front. The sensor casing (50) may be disposed so as to be in contact with the bottom plate (12c).

[0070] The sensor casing (50) is disposed below the internal fan (30). The sensor casing (50) is disposed below the internal heat exchanger (29). The sensor casing (50) accommodates the refrigerant sensor (110), and therefore the detection element (110a) is disposed below the internal heat exchanger (29).

[0071] As shown in Fig. 5, the sensor casing (50) has a main body (56) and a lid (57). The main body (56) is formed in a box shape with an open front. The main body (56) has a first flange (56b) for fixing the lid (57). The first flange (56b) is formed so as to extend outward from the edge of the opening on the front surface of the main body (56).

[0072] The main body (56) has a first insertion hole (58). The first insertion hole (58) is formed in a rear surface (56a) of the main body (56). The first insertion hole (58) connects the inside of the main body (56) with the air passage (19). The first insertion hole (58) is a hole through which a second receiving portion (111b) of the housing (111), which will be described later, is inserted.

[0073] The lid portion (57) is a plate-like member formed in a generally rectangular shape. The lid portion (57) closes the opening on the front surface of the main body portion (56). The lid portion (57) contacts the first flange portion (56b). The lid portion (57) and the main body portion (56) are fixed to each other by inserting bolts (90), which serve as fastening members, through the lid portion (57) and the first flange portion (56b). When the sensor casing (50) is attached to the casing main body (12), the rear surface (56a) of the main body portion (56) is exposed to the air passage (19). When the sensor casing (50) is attached to the casing main body (12), the lid portion (57) is exposed to the external storage space (14).

[0074] (4-2) Housing The housing (111) has a first receiving portion (111a) that receives the detection board (110b) and a second receiving portion (111b) that receives the detection element (110a) and the filter (112).

[0075] The first container (111a) is shaped like a flat box and is disposed in the space within the main body (56). Specifically, the first container (111a) is disposed within the main body (56) near the rear surface (56a).

[0076] The second housing portion (111b) is formed in a cylindrical shape. The second housing portion (111b) extends from the first housing portion (111a) toward the inside of the air passage (19). Specifically, the second housing portion (111b) passes through the first insertion hole (58) from the first housing portion (111a) and extends horizontally toward the air passage (19). A tip portion of the second housing portion (111b) protrudes into the air passage (19). A first opening (51) is formed at the tip of the second housing portion (111b). The first opening (51) connects the detection element (110a) and the air passage (19). In this embodiment, the sensor casing (50) and the housing (111) correspond to the casing (11, 50) of the present disclosure.

[0077] The first opening (51) opens in the horizontal direction (the direction of the two-dot chain arrow in FIG. 5). "The first opening (51) faces the horizontal direction" means that the opening surface of the first opening (51) is not inclined relative to the horizontal direction. Also, "The first opening (51) faces the horizontal direction" means that the opening surface of the first opening (51) is formed in a plane perpendicular to the horizontal direction (vertical plane).

[0078] The first opening (51) opens in a direction perpendicular to the air flow in the air passage (19). The phrase "the first opening (51) is perpendicular to the air flow in the air passage (19)" means that the opening surface of the first opening (51) is formed along the air flow and is not inclined relative to the air flow direction. The phrase "the first opening (51) is perpendicular to the air flow in the air passage (19)" means that the opening surface of the first opening (51) faces neither upstream nor downstream of the air flow.

[0079] The filter (112) and the detection element (110a) are arranged in the second container (111b) in this order from the first opening (51) toward the first container (111a). The filter (112) is arranged near the first opening (51), and the detection element (110a) is arranged near the first container (111a). In this way, the filter (112) captures dust contained in the air flowing from the air passage (19) into the first opening (51).

[0080] (4-3) Air flow in the air passage During operation of the internal fan (30), an airflow flows from above to below in the air passage (19) (in the direction of the solid arrow in FIG. 5 ). For example, refrigerant leaking from the internal heat exchanger (29) mixes with air passing through the internal heat exchanger (29) and flows through the air passage (19). Because the first opening (51) is opened perpendicular to the air passage (19), part of the air containing refrigerant flows into the first opening (51) of the refrigerant sensor (110) and comes into contact with the detection element (110a). In this way, refrigerant leaked into the air can be detected during operation of the internal fan (30).

[0081] While the internal fan (30) is stopped, no airflow is generated in the air passage (19) by the internal fan (30). In this case, the refrigerant leaking from the internal heat exchanger (29) accumulates on the bottom surface of the interior of the compartment and then gradually diffuses upward (in the direction of the dashed arrow in FIG. 5 ). At this time, since the first opening (51) is open in a direction perpendicular to the air passage (19), the air containing the refrigerant flows gradually upward from the bottom through the air passage (19), flows into the first opening (51), and comes into contact with the detection element (110a).

[0082] (5) Features (5-1) Feature 1 The container refrigeration system (10) of this embodiment is disposed below the internal heat exchanger (29) and includes a detection element (110a) (detection portion (110a)) that detects refrigerant leaking into the container (1), a housing (111) that accommodates the detection element (110a), and a sensor casing (50) (casing (111, 50)). The housing (111) has a first opening (51) that connects the detection element (110a) to the air passage (19), and the first opening (51) opens horizontally when viewed from the air passage (19) side.

[0083] According to the present embodiment, the first opening (51) opens horizontally, and therefore, when the first conveyor (30) is stopped, the leaked refrigerant accumulated in the lower part of the container (1) diffuses upward and easily enters the first opening (51). This reduces the time it takes for the detection element (110a) to detect the leaked refrigerant inside the container (1), and allows the leaked refrigerant to be detected relatively quickly.

[0084] (5-2) Feature 2 In the container refrigeration unit (10) of this embodiment, the first opening (51) opens in a direction perpendicular to the air flow in the air passage (19).

[0085] When the pressure acting on the detection element (110a) increases due to the air flowing through the air passage (19), the detection element (110a) is more likely to erroneously detect the refrigerant. In contrast, in this embodiment, the first opening (51) is opened in a direction perpendicular to the air flow in the air passage (19), and therefore, the pressure acting on the first opening (51) can be suppressed. This makes it possible to suppress erroneous detection of the refrigerant.

[0086] (5-3) Feature 3 In this embodiment, the sensor casing (50) is provided on the side wall (16a) of the external casing (16), thereby enabling maintenance of the refrigerant sensor (110) from outside the container (1) without entering the container (1).

[0087] (6) Variations Modifications of the above embodiment will be described. Below, configurations different from the above embodiment will be described.

[0088] (6-1) Variation 1 As shown in FIG. 6 , the container refrigeration unit (10) of the first modification includes a windbreak plate (120). The windbreak plate (120) is an example of a pressure reduction section (120). The windbreak plate (120) is disposed in the air passage (19) above the first opening (51). In the air passage (19), an airflow is generated from above to below by the internal fan (30). The windbreak plate (120) is a plate member that blocks the airflow toward the first opening (51). In other words, the windbreak plate (120) is a plate member that blocks a part of the airflow toward the first opening (51). In yet another way, the windbreak plate (120) is a plate member that suppresses the dynamic pressure acting on the first opening (51) due to the airflow.

[0089] Specifically, the windshield plate (120) is erected rearward from the rear surface (56a) of the sensor casing (50) so as to hide the tip of the second housing portion (111b) when viewed from above the air passage (19). The windshield plate (120) is installed so that its plate surface is perpendicular or oblique to the longitudinal direction of the air passage (19) or the direction of the airflow. In other words, the windshield plate (120) is not installed so that its plate surface is parallel to the longitudinal direction of the air passage (19) or the direction of the airflow.

[0090] The windshield plate (120) may be located in any position that suppresses the dynamic pressure acting on the first opening (51). In consideration of the first opening (51) being less susceptible to the influence of the airflow, the windshield plate (120) is preferably located as close to the first opening (51) as possible.

[0091] The windshield plate (120) may have any shape as long as it can suppress the dynamic pressure acting on the first opening (51). In consideration of the resistance to the airflow at the first opening (51), the larger the surface of the windshield plate (120) is, the more preferable it is, as long as it does not obstruct the airflow in the air passage (19).

[0092] The windbreak plate (120) reduces the speed of the air flowing through the air passage (19) when the air comes into contact with the windbreak plate (120). As a result, the speed of the air between the windbreak plate (120) and the first opening (51) becomes slower than the speed of the air around the windbreak plate (120). In this way, the dynamic pressure on the first opening (51) is reduced. In this way, the windbreak plate (120) is disposed in the air passage (19) and reduces the pressure acting on the first opening (51) by the air conveyed by the first conveyor (30).

[0093] (6-2) Variation 2 As shown in Figures 7 to 9, the sensor casing (50) of the second modification has a different configuration from the sensor casing (50) of the above embodiment. The sensor casing (50) of the second modification corresponds to the casing (50) of the present disclosure. In the sensor casing (50) of the second modification, the main body (56) is disposed in the external casing (16). Specifically, the main body (56) of the sensor casing (50) is fixed to the side wall (16a) of the external casing (16).

[0094] The lid (57) of the sensor casing (50) of Modification 2 is formed in the shape of a rectangular tray. The lid (57) has a fixing plate (57a) for fixing the refrigerant sensor (110) and a peripheral wall (57b) extending from the outer periphery of the fixing plate (57a) toward the main body (56). The lid (57) and the main body (56) are fixed to each other by a fastening member (not shown).

[0095] In the second modification, the refrigerant sensor (110) is arranged so that the entire refrigerant sensor (110) is accommodated in the sensor casing (50). Specifically, the first accommodation portion (111a) of the housing (111) is fixed to the fixing plate (57a). The first accommodation portion (111a) is arranged toward the center of the fixing plate (57a). The second accommodation portion (111b) of the housing (111) is accommodated in the main body (56) so that its tip faces the air passage (19).

[0096] As shown in FIG. 9, the main body (56) of the second modification includes a second flange (56c), an attachment portion (59), a first ventilation member (61), a second ventilation member (62), and a receiving portion (53).

[0097] The second flange portion (56c) is a portion that is fixed to the external casing (16). Specifically, the second flange portion (56c) is formed so as to extend to both the left and right sides of the rear surface (56a) of the main body portion (56). Mounting holes (H) are formed in the second flange portion (56c). Fastening members (not shown) such as bolts are inserted through the mounting holes (H) and the side walls (16a) of the external casing (16), thereby fixing the sensor casing (50) to the external casing (16).

[0098] As shown in FIGS. 8 and 9, the attachment portion (59) is an area where the first ventilation member (61) is attached. The attachment portion (59) is formed in the lower part of the rear surface (56a). The attachment portion (59) is formed to be recessed. A first communication hole (81) is formed in the attachment portion (59). The first communication hole (81) is a circular opening that connects the interior of the main body portion (56) with the first ventilation member (61). The first communication hole (81) is formed to contact the lower end of the rear surface (56a).

[0099] A second communication hole (82) is formed in the rear surface (56a) of the main body (56). The second communication hole (82) is an opening into which one end of the second ventilation member (62) is inserted. The second communication hole (82) is formed in the upper part of the rear surface (56a). The second communication hole (82) is an elongated hole extending in the left-right direction. Gaps are formed between the second communication hole (82) and the second ventilation member (62). These gaps are formed below and on the left and right sides of the second ventilation member (62).

[0100] The first ventilation member (61) and the second ventilation member (62) are cylindrical. Both ends of the first ventilation member (61) and the second ventilation member (62) are open. The first ventilation member (61) and the second ventilation member (62) connect the internal space of the main body (56) to the air passage (19). The first ventilation member (61) and the second ventilation member (62) supply air taken in from the air passage (19) to the refrigerant sensor (110) in the main body (56), and discharge the air taken into the main body (56) back to the air passage (19). The first ventilation member (61) and the second ventilation member (62) extend from the rear surface (56a) of the main body (56) toward the air passage (19). Specifically, the first ventilation member (61) and the second ventilation member (62) are provided so as to penetrate the side wall of the internal casing (18) and the side wall of the external casing (16) that are adjacent to each other in the front-rear direction.

[0101] The first ventilation member (61) extends obliquely downward from the lower part of the rear surface (56a) of the main body (56) toward the air passage (19). In other words, the first ventilation member (61) extends toward the downstream side of the air flow in the air passage (19) when the internal fan (30) is operating.

[0102] One end of the first ventilation member (61) opens toward the refrigerant sensor (110) in the main body (56). The opening at one end of the first ventilation member (61) communicates with the first communication hole (81). One end of the first ventilation member (61) is fixed to the mounting portion (59). Specifically, a disk-shaped third flange portion (61a) is formed at one end of the first ventilation member (61), and the third flange portion (61a) comes into contact with the mounting portion (59), thereby fixing the first ventilation member (61) to the main body (56).

[0103] The opening at the other end of the first ventilation member (61) corresponds to the first opening (51). The first opening (51) faces the air passage (19). The first opening (51) opens in the horizontal direction. Specifically, the opening surface of the first opening (51) is formed to be a vertical surface. In other words, the opening surface of the first opening (51) is formed to be along the air flow in the air passage (19).

[0104] The second ventilation member (62) is an example of a tubular portion (62). The second ventilation member (62) has a first tubular portion (62a) and a second tubular portion (62b) formed in this order from the main body portion (56) toward the air passage (19).

[0105] The first cylindrical portion (62a) extends obliquely upward from an upper portion of the rear surface (56a) of the main body (56) toward the air passage (19). One end of the first cylindrical portion (62a) is inserted into the second communication hole (82). One end of the first cylindrical portion (62a) is disposed inside the main body (56). One end of the first cylindrical portion (62a) opens toward the refrigerant sensor (110) inside the main body (56). One end of the first cylindrical portion (62a) is disposed so as to contact the upper edge of the second communication hole (82).

[0106] The second cylindrical portion (62b) is connected to the first cylindrical portion (62a). The second cylindrical portion (62b) is formed so that the cross-sectional area of ​​the flow path is larger than that of the first cylindrical portion (62a). The cross-sectional area of ​​the flow path is the area of ​​the opening formed in a cross section perpendicular to the cylindrical axis direction. The second cylindrical portion (62b) extends upward along the inner surface of the side wall of the internal casing (18), which forms the inner surface of the air passage (19). In other words, the second cylindrical portion (62b) extends vertically upward through the air passage (19) from one end of the first cylindrical portion (62a). As shown in FIG. 8 , the lower portion of the side surface of the second cylindrical portion (62b) that extends in the vertical direction, on the side facing the partition plate (13), is curved and connected to the first cylindrical portion (62a). This curved shape facilitates guiding air passing through the second cylindrical portion (62b) to the first cylindrical portion (62a).

[0107] A second opening (52) is formed at one end of the second tubular portion (62b). The second opening (52) opens toward the upstream side of the air flow in the air passage (19). The second opening (52) faces upward in the air passage (19). Thus, the sensor casing (50) has the second opening (52). The second opening (52) connects the detection element (110a) to the air passage (19). The second ventilation member (62) has the second opening (52) and connects to the detection element (110a).

[0108] The second opening (52) is disposed below the internal heat exchanger (29). That is, the second opening (52) is disposed below the internal fan (30). Since the first opening (51) is disposed below the second opening (52), the first opening (51) and the second opening (52) are disposed below the internal fan (30).

[0109] The second opening (52) is formed so that its opening surface is inclined with respect to the air flow in the air passage (19). Specifically, as shown in Figures 7 and 8, in the vertical cross section of the air passage (19), the second cylindrical portion (62b) is closer to the side wall of the internal casing (18) than to the partition plate (13) in the air passage (19), and the opening surface of the second opening (52) is inclined downward from the side wall of the internal casing (18) toward the partition plate (13). In other words, the second opening (52) is formed so that, in the vertical cross section of the air passage (19), the angle formed between the opening surface of the second opening (52) and the side wall of the internal casing (18) of the air passage (19) is an obtuse angle.

[0110] A filter portion (55) is formed on the opening surface of the second opening portion (52). The filter portion (55) prevents foreign matter contained in the air flowing through the air passage (19) from entering the second ventilation member (62). The filter portion (55) is formed in a mesh shape. The filter portion (55) is an example of a prevention portion (55).

[0111] 8 and 9, the receiving portion (53) is located between the second opening (52) and the detection element (110a) and receives water that has flowed from the air passage (19) into the second opening (52). Specifically, the receiving portion (53) receives water contained in air that flows into the second ventilation member (62) through the second opening (52). The receiving portion (53) extends from a lower portion of the opening edge of the second communication hole (82) toward the inside of the main body portion (56). The receiving portion (53) is formed in a bowl shape so as to receive water that flows into the main body portion (56) from one end of the second ventilation member (62).

[0112] The receiving portion (53) is provided across the gap between one end of the second ventilation member (62) and the refrigerant sensor (110). In other words, the receiving portion (53) is provided across the shortest path between the one end of the second ventilation member (62) and the tip of the second housing portion (111b) of the refrigerant sensor (110).

[0113] The receiving portion (53) is formed with a discharge port (54). The discharge port (54) discharges water adhering to the receiving portion (53) downward of the main body portion (56). The discharge port (54) is formed in the shape of a slit extending in the front-rear direction. A plurality of discharge ports (54) may be formed.

[0114] The water discharged from the outlet (54) falls downward within the main body (56). The falling water passes through the first communication hole (81) and the first ventilation member (61) and is discharged into the air passage (19). In this manner, the outlet (54) discharges the water that has flowed from the air passage (19) into the second opening (52) between the second opening (52) and the detection element (110a) to the outside.

[0115] When the internal fan (30) is in operation, part of the air flowing from the upper part to the lower part of the air passage (19) flows into the second ventilation member (62) through the second opening (52). When the air passing through the second cylindrical portion (62b) flows into the first cylindrical portion (62a) which is narrower than the second cylindrical portion (62b), a pressure loss occurs in the air, and the total pressure decreases.

[0116] The air flowing from the first tubular portion (62a) into the main body (56) is blown out into a space wider than the opening of the first tubular portion (62a), and therefore the air velocity is reduced. This reduces the air velocity flowing through the main body (56). In particular, the receiving portion (53) disposed between the opening of the second ventilation member (62) and the refrigerant sensor (110) blocks the airflow blowing from the opening of the second ventilation member (62) toward the refrigerant sensor (110), thereby reducing the dynamic pressure generated at the tip of the second accommodation portion (111b) that accommodates the detection element (110a).

[0117] When a portion of the air in the main body (56) flows into the second container (111b), the detecting element (110a) comes into contact with the air. This allows the refrigerant concentration in the air to be detected. The air flowing through the main body (56) flows into the first ventilation member (61) through the first communication hole (81) and is discharged to the air passage (19) through the first opening (51).

[0118] Suppose that refrigerant begins to leak from around the internal heat exchanger (29) while the internal fan (30) is stopped. The refrigerant accumulates on the bottom of the container (1) and gradually diffuses upward within the container. Because the first opening (51) opens horizontally, some of the air containing refrigerant diffusing upward in the air passage (19) flows into the first opening (51). Because the first ventilation member (61) extends upward from the air passage (19) toward the main body (56), the air that has flowed into the first opening (51) passes through the first ventilation member (61) and flows into the main body (56). The air containing refrigerant also rises within the main body (56). In the process, the air that flows into the second storage section (111b) comes into contact with the detection element of the second storage section (111b), thereby detecting the refrigerant concentration. The air in the main body (56) flows through the second ventilation member (62) via the second communication hole (82) and flows out into the air passage (19) through the second opening (52).

[0119] In the second modification, the sensor casing (50) has a second ventilation member (62) communicating with the main body (56). The inner diameter of the second ventilation member (62) is relatively small, which reduces the speed of the air flowing from the second ventilation member (62) into the main body (56). This reduces the pressure acting on the detection element (110a) of the refrigerant sensor (110), thereby reducing false detection of the refrigerant.

[0120] In the second modification, the second ventilation member (62) has a first tubular portion (62a) and a second tubular portion (62b). Because the cross-sectional area of ​​the first tubular portion (62a) is smaller than the cross-sectional area of ​​the second tubular portion (62b), a pressure loss occurs when air flows from the second tubular portion (62b) into the first tubular portion (62a), resulting in a decrease in total pressure. The decrease in total pressure reduces the dynamic pressure of air flowing from the first tubular portion (62a) into the main body portion (56), which is a relatively large space, and thus reduces the air velocity. Specifically, if the tubular portion (62) did not have the first tubular portion (62a) and were composed only of the second tubular portion (62b), the pressure loss of the air passing through the tubular portion (62) would be reduced, and the decrease in total pressure would be suppressed. As a result, the dynamic pressure of the air flowing into the main body portion (56) is less likely to be reduced. However, in this example, the total pressure of the air flowing from the second tubular portion (62b) to the first tubular portion (62a) is reduced, and therefore the dynamic pressure of the air flowing into the main body portion (56) can be reduced accordingly.

[0121] In the second modification, the second opening (52) opens toward the upstream side of the air flow in the air passage (19). Therefore, while the internal fan (30) is operating, air can be easily taken in through the second opening (52) by utilizing dynamic pressure due to the air flow. Furthermore, while the internal fan (30) is not operating, air can be easily taken in through the first opening (51) by utilizing natural diffusion of air. In this way, the time from when a refrigerant leak occurs to when it is detected can be shortened both when the internal fan (30) is operating and when it is not operating.

[0122] In the second modification, the first opening (51) and the second opening (52) are disposed below the internal fan (30). As a result, the first opening (51) and the second opening (52) are disposed below the internal fan (30) in the air passage (19), and thus the wind pressure acting on the second opening (52) increases, making it easier for the second opening (52) to take in air.

[0123] In the second modification, the second opening (52) is formed so that its opening surface is inclined with respect to the air flow in the air passage (19). The area of ​​the opening surface of the second opening (52) can be increased, so that a large amount of air flowing through the air passage (19) can be taken in. The opening surface of the second opening (52) is inclined downward from the internal casing (18) toward the partition plate (13), so that ventilation resistance of the air flowing through the air passage (19) can be reduced.

[0124] In the second modification, a suppression portion (55) is formed on the opening surface of the second opening (52). This suppresses foreign matter contained in the air from coming into contact with the detection element (110a), thereby suppressing breakdown of the detection element (110a) and false detection of the refrigerant.

[0125] In the second modification, the receiving portion (53) is provided across the gap between the second communication hole (82) and the refrigerant sensor (110). The receiving portion (53) prevents water from splashing into the main body (56) and from adhering to the refrigerant sensor (110). The receiving portion (53) also prevents air flowing into the main body (56) from the second ventilation member (62) from directly hitting the refrigerant sensor (110). This reduces the dynamic pressure acting on the detection element (110a). In this way, the receiving portion (53) prevents the refrigerant sensor (110) from malfunctioning or erroneously detecting the refrigerant.

[0126] In the second modification, the outlet (54) is formed in the receiver (53), so that water that has flowed into the main body (56) together with air from the second ventilation member (62) can be discharged to the outside of the main body (56).

[0127] (6-3) Variation 3 10 to 12, the sensor casing (50) of the third modification has a different configuration from the sensor casing (50) of the above embodiment and the above modifications. In the third modification, the sensor casing (50) corresponds to the casing (50) of the present disclosure. In the sensor casing (50) of the third modification, the main body (56) is disposed in the external casing (16). Specifically, the main body (56) of the sensor casing (50) is fixed to the sidewall of the external casing (16).

[0128] The sensor casing (50) has a main body portion (56) and a closing portion (74). The main body portion (56) of this modified example is formed in a box shape with an open rear end. In other words, the rear surface of the main body portion (56) is open over substantially the entire area. The closing portion (74) covers the opening on the rear surface of the main body portion (56). The closing portion (74) is fixed to the main body portion (56). Specifically, a fourth flange portion (56d) is formed on the edge of the opening of the main body portion (56), and a bolt (90), which is a fastening member, is inserted between the closing portion (74) and the fourth flange portion (56d).

[0129] As shown in Fig. 12, a refrigerant sensor (110) is disposed in the main body (56). The refrigerant sensor (110) is fixed to the front wall of the main body (56). The refrigerant sensor (110) is disposed at a position through which air flows through the main body (56). The air flowing through the second main body (56) comes into contact with a detection element (110a) in the second container (111b).

[0130] As shown in Fig. 11, the sensor casing (50) has a third ventilation member (63) and a fourth ventilation member (64). The third ventilation member (63) and the fourth ventilation member (64) are cylindrical members. The third ventilation member (63) and the fourth ventilation member (64) communicate between the inside of the main body portion (56) and the air passage (19). The third ventilation member (63) and the fourth ventilation member (64) are formed in the closing portion (74).

[0131] The third ventilation member (63) extends substantially horizontally from the lower part of the closing portion (74) toward the air passage (19) and then extends downward within the air passage (19). Specifically, the third ventilation member (63) extends horizontally from the lower end of the main body (56), penetrates through the side walls of the external casing (16) and the internal casing (18), which are aligned in the front-to-rear direction, and then extends downward from the lower surface of the air passage (19) to a predetermined height position.

[0132] The opening at the end of the third ventilation member (63) opens downward. The opening at the end of the third ventilation member (63) corresponds to the third opening (73) of the present disclosure. The third opening (73) opens downstream in the airflow direction when the internal fan (30) is operating.

[0133] A guard portion (75) is provided at the third opening (73). The guard portion (75) has a large number of pores formed therein, which prevents foreign matter such as dust from entering the third ventilation member (63).

[0134] The fourth ventilation member (64) extends from an upper portion of the closing portion (74) toward the air passage (19) in a generally horizontal direction, and then extends downward within the air passage (19). Specifically, the fourth ventilation member (64) has a large-diameter portion (64a) and a small-diameter portion (64b). The large-diameter portion (64a) is provided at an upper portion of the closing portion (74) and extends horizontally. The inner diameter of the large-diameter portion (64a) is larger than the inner diameters of the small-diameter portion (64b) and the third ventilation member (63). The large-diameter portion (64a) penetrates the side wall of the external casing (16) and the side wall of the internal casing (18), which are aligned in the front-to-rear direction. The small-diameter portion (64b) is continuous with the large-diameter portion (64a). The small-diameter portion (64b) extends downward within the air passage (19). In this modification, the opening at the end of the small diameter portion (64b) corresponds to the first opening portion (51).

[0135] The first opening (51) opens downward. The first opening (51) opens downstream in the direction of the airflow when the internal fan (30) is operating. This prevents water dropping from the internal heat exchanger (29) from flowing into the third opening (73).

[0136] A guard portion (75) is provided at the first opening (51). The guard portion (75) prevents foreign matter such as dust from entering the fourth ventilation member (64).

[0137] In this modification, the first opening (51) is provided at a height of 1 m from the bottom surface of the air passage (19). The first opening (51) is located above the third opening (73). In other words, the third opening (73) is located below the first opening (51).

[0138] As shown in Fig. 12, the container refrigeration unit (10) of the third modification includes a suction fan (130). The suction fan (130) is an example of a second conveyor (130). The suction fan (130) draws air from the air passage (19) into the first opening (51).

[0139] The suction fan (130) is provided in the sensor casing (50). Specifically, the suction fan (130) is provided in a portion of the main body (56) where the large-diameter portion (64a) is connected. When the suction fan (130) is operating, an airflow is generated in the main body (56) from the fourth ventilation member (64) to the third ventilation member (63). The suction fan (130) has a suction fan body (130b) and a suction fan motor (130a).

[0140] The suction fan body (130b) is a propeller fan. The size of the suction fan body (130b) is smaller than the size of the large-diameter portion (64a). Specifically, the diameter of the suction fan body (130b) is smaller than the inner diameter of the large-diameter portion (64a). By making the diameter of the suction fan body (130b) larger than the inner diameter of the large-diameter portion (64a), pressure loss when the suction fan (130) draws air can be reduced.

[0141] The suction fan motor (130a) drives a fan when energized. The suction fan motor (130a) is connected to a power supply different from the power supply that supplies power to the internal fan motor (30b). In this way, the internal fan motor (30b) and the suction fan motor (130a) are supplied with power from different power supplies. The second power supply may be a replaceable battery, such as a cell.

[0142] In this modification, the suction fan (130) draws air at a height of 1 m or less from the bottom of the air passage (19) to the first opening (51). The wind speed of the suction fan (130) in this embodiment will now be described.

[0143] Weight of fluid resisting suction force (kg m / s 2 ) is W, and the suction force of the suction fan (130) (kg m / s 2 ) to F fan When W=F fan This relationship can be used to calculate the wind speed of the intake fan (130). Specifically, W and F fan are expressed by the following equations (1) and (2), respectively.

[0144]

number

[0145]

number

[0146] ρ air : air density (kg / m 3 ), ρ yf : Density of R1234yf refrigerant (kg / m 3 ), g: Gravitational acceleration (m / s 2 ), A: Cross-sectional area (m 2 ), h: Height of fluid lift (m) Equation (1), Equation (2) and Q=A×v air Based on v air can be expressed by equation (3).

[0147]

number

[0148] Air density (ρ air The density (ρ) of 1234yf refrigerant can be calculated based on the molecular weight of dry air, the molecular weight of water vapor, the gas constant, temperature, saturated water vapor pressure, atmospheric pressure, and relative humidity. yf ) can be calculated based on the molecular weight of the refrigerant, the gas constant, temperature, and atmospheric pressure. air =0.65kg / m 3 Then, the minimum required wind speed for the intake fan (130) to lift the fluid by 1 cm can be expressed by equation (4).

[0149]

number

[0150] The density of R1234yf is ρ yf =3.95kg / m 3 When the suction fan (130) lifts the fluid by 1 cm, the minimum required wind speed is v air =0.703 m / s.

[0151] Since the first opening (51) is located at a height of 1 m from the bottom surface of the air passage (19), the wind speed required for the suction fan (130) to suck in the fluid located 1 m below the first opening (51) can be expressed by equation (5) by substituting h=1 m into equation (3).

[0152]

number

[0153] The density of R1234yf is ρ yf =3.95kg / m 3When the suction fan (130) sucks in the fluid 1 m below, the required wind speed is v based on equation (5). air =7.03 m / s.

[0154] In this way, by setting the air velocity of the suction fan (130) to 7.03 m / s or more, the air containing the refrigerant accumulated on the bottom surface of the air passage (19) can be sucked up to the refrigerant sensor (110). Therefore, the time from when the refrigerant leaks until when the refrigerant is detected can be shortened, and the refrigerant leakage can be detected relatively quickly.

[0155] The air flow in the air passage (19) of this embodiment will be described below: The intake fan (130) is assumed to be constantly operating whether the internal fan (30) is operating or not.

[0156] As shown in FIG. 12(B), during operation of the internal fan (30), a portion of the air flowing downward in the air passage (19) is sucked by the suction fan (130) through the first opening (51) into the fourth ventilation member (64). The air sucked into the fourth ventilation member (64) flows into the main body (56) and then flows through the main body (56) toward the third ventilation member (63). A portion of the air flowing through the main body (56) flows into the second housing portion (111b) of the refrigerant sensor (110) and contacts the detection element (110a). This allows the refrigerant sensor (110) to detect the refrigerant contained in the air. The air that has flowed into the third ventilation member (63) is discharged through the third opening (73) into the air passage (19). In this way, the third opening (73) blows the air sucked into the first opening (51) into the air passage (19). When the internal fan (30) is stopped, the air sucked in by the suction fan (130) through the first opening (51) flows into the main body (56), flows toward the third ventilation member (63), and is discharged through the third opening (73) to the air passage (19).

[0157] In the third modification, the suction fan (130) conveys the internal air to the refrigerant sensor (110). This makes it possible to detect a leaking refrigerant relatively quickly without waiting for the refrigerant in the air passage (19) to diffuse upward while the internal fan (30) is stopped, as in the above-described embodiment and modifications.

[0158] In the third modification, the suction fan motor (130a) is supplied with power from a power source different from that of the internal fan motor (30b). Therefore, even if the power supply to the internal fan (30) is interrupted due to a malfunction, for example, the suction fan (130) can still operate. Therefore, even if the internal fan (30) is stopped, the suction fan (130) can be operated to detect refrigerant leaking into the internal compartment.

[0159] In the third modification, when the internal fan (30) is stopped, the air velocity of the suction fan (130) is set to 7.03 m / s or more, so that the refrigerant accumulated on the bottom surface of the interior of the container (1) can be forcibly sucked into the first opening (51) by the suction fan (130).

[0160] In the third modification, the first opening (51) is located above the third opening (73). Therefore, the pressure acting on the third opening (73), which is closer to the internal fan (30), is higher than the pressure acting on the first opening (51). The suction fan (130) can draw air through the first opening (51), which has a higher pressure, and blow the air out through the third opening (73), which has a lower pressure. If the first opening (51) were located below the third opening (73), the suction fan (130) would have to direct air from the first opening (51), which has a lower pressure, to the third opening (73), which has a higher pressure, which increases the operating load. However, in this example, an increase in the operating load of the suction fan (130) due to the pressure difference between the first opening (51) and the third opening (73) can be suppressed. Furthermore, if the first opening (51) is located relatively close to the third opening (73), there is a risk that the first opening (51) will suck in the air discharged from the third opening (73). Therefore, it is preferable that the third opening (73) be located away from the first opening (51).

[0161] (7) Other embodiments The above embodiment and each of the above modifications may be configured as follows.

[0162] In the above embodiment and the above modifications 1 and 2, the first opening (51) may face downward relative to the horizontal direction. Specifically, the first opening (51) may be formed so that at least a portion of its opening surface is inclined downward. For example, the first opening (51) may have an entire opening surface inclined downward, or a portion of the opening surface may be formed downward and the remaining portion may be formed perpendicular to the horizontal direction.

[0163] In the above embodiment and the first and second modifications, the first opening (51) may face downstream of the air flow in the air passage (19) when the internal fan (30) is operating. Specifically, the first opening (51) may be formed so that at least a part of its opening surface is inclined toward the downstream side of the air flow in the air passage (19). For example, the first opening (51) may be formed so that the entire opening surface is inclined toward the downstream side of the air flow in the air passage (19), or so that a part of the opening surface is formed toward the downstream side of the air flow and the remaining part is parallel to the air flow.

[0164] In the above embodiment and Modification 1, even if the direction of air flow in the air passage (19) is inclined with respect to the vertical, it is sufficient that the first opening (51) opens in the horizontal direction. Also, in the above embodiment and Modification 1, even if the direction of air flow in the air passage (19) is inclined with respect to the vertical, it is sufficient that the first opening (51) opens in a direction perpendicular to the air flow or downstream.

[0165] In the above embodiment, the sensor casing (50) and the housing (111) may be integrally formed.

[0166] In the first modification, the windshield (120) only needs to be disposed in the air passage (19), and does not necessarily have to be formed in the sensor casing (50).

[0167] In the second modification, the sensor casing (50) does not necessarily have to have the receiving portion (53). Furthermore, if the sensor casing (50) has the receiving portion (53), it is sufficient that the receiving portion (53) can receive water flowing into the main body (56) from one end of the second ventilation member (62), and therefore the receiving portion (53) does not necessarily have to be provided in the second communication hole (82).

[0168] In the second modification, the sensor casing (50) does not necessarily have to have the outlet (54). Furthermore, when the sensor casing (50) has the outlet (54), it is sufficient that the outlet (54) can discharge water that flows into the main body (56) to the outside of the main body (56), and the outlet (54) does not necessarily have to be provided in the receiver (53).

[0169] In the second modification, the sensor casing (50) only needs to have the second opening (52), and does not necessarily have to have the second ventilation member (62).

[0170] In the second modification, the second ventilation member (62) may have a tubular portion whose flow path cross-sectional area is different from that of the first tubular portion (62a) and the second tubular portion (62b). The second ventilation member (62) may have any shape as long as it is tubular, and may not have the first tubular portion (62a) and the second tubular portion (62b). For example, the inner surface of the second ventilation member (62) may be tapered so that the diameter decreases from the second opening (52) toward the main body (56).

[0171] In the second modification, the filter portion (55) may be formed integrally with or separate from the second ventilation member (62). The second opening (52) may be formed so as to prevent foreign matter from entering, and the second opening (52) may have a structure that prevents foreign matter from entering.

[0172] In the second modification, the sensor casing (50) may be configured such that the main body (56), the first ventilation member (61), and the second ventilation member (62) are integrally formed.

[0173] In the third modification, the sensor casing (50) may be configured such that the closing portion (74), the third ventilation member (63), and the fourth ventilation member (64) are integrally formed.

[0174] In the third modification, the first opening (51) may be located at a height of 1 m or less from the bottom surface of the air passage (19), for example, at a height of 0.2 m, 0.4 m, 0.6 m, or 0.8 m.

[0175] In the third modification, the first opening (51) and the third opening (73) may be at the same height. Specifically, the opening planes of the first opening (51) and the third opening (73) may be at the same height.

[0176] In the third modification, the refrigerant may be R32, R744 (CO), R290 (propane), or R454C. In the case of R32, the refrigerant density ρ is 1.80 kg / m. 3 The minimum wind speed required for the interior fan (30) to lift the air by 1 cm is v air Therefore, when the first opening (51) is located at a height of 1 m from the bottom of the air passage (19), the required wind speed v air is calculated based on equation (5). air = 4.15 m / s. Similarly, for R744 (CO2), the refrigerant density ρ = 1.52 kg / m 3 The minimum required wind speed is v air = 0.362 m / s, and the required wind speed v air is 3.62 m / s. In the case of R290 (propane), the refrigerant density ρ = 1.53 kg / m 3 The minimum required wind speed is v air = 0.362 m / s, and the required wind speed v airis 3.62 m / s. In the case of R454C, the refrigerant density ρ = 3.144 kg / m 3 The minimum required wind speed is v air = 0.612 m / s, and the required wind speed v air is 6.12 m / s.

[0177] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and detail are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments and modifications may be combined or substituted as appropriate as long as the functionality of the subject matter of this disclosure is not impaired. The terms "first," "second," etc., described above, are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms. [Industrial Applicability]

[0178] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for container refrigeration systems. [Explanation of symbols]

[0179] 1 container 3. Containment space 5 Outside space 10 Container refrigeration equipment 16a Side wall (wall part) 19 Air passage 29 Internal heat exchanger (heat exchanger) 30 In-storage fan (first conveyor) 30b First electric motor (interior fan motor) 50 Sensor casing (casing) 51 First opening 52 Second Opening 53 Receiving part 54 Outlet 55 Suppression section (filter section) 62 Cylinder portion (second ventilation member) 62a First cylindrical part 62b Second cylinder part 73 Third Opening 110a detection unit (detection element) 111 Housing (casing) 120 Pressure reduction section (windbreak plate) 130 Second conveyor (suction fan) 130a Second electric motor (suction fan motor) R Refrigerant circuit

Claims

1. A container refrigeration unit provided in a container (1) having a refrigerant circuit (R) that performs a refrigeration cycle, the container (1) having an interior partitioned into an accommodation space (3) and an air passage (19) communicating with the accommodation space (3), a first conveyor (30) for circulating the air inside the container (1) between the storage space (3) and the air passage (19); a heat exchanger (29) disposed in the air passage (19); a detector (110a) disposed below the heat exchanger (29) and configured to detect refrigerant leaking into the container (1); a casing (50, 111) that houses the detection part (110a), the casing (50, 111) has a first opening (51) and a second opening (52) that connect the detection portion (110a) and the air passage (19); The first opening (51) opens in a horizontal direction or downward from the horizontal direction, the second opening (52) opens toward the upstream side of the air flow in the air passage (19), the first conveyor (30) is disposed in the air passage (19); the first opening (51) and the second opening (52) are disposed below the first conveyor (30); The density of the refrigerant is greater than the density of air. Refrigeration equipment for containers.

2. A container refrigeration unit provided in a container (1) having a refrigerant circuit (R) that performs a refrigeration cycle, the container (1) having an interior partitioned into an accommodation space (3) and an air passage (19) communicating with the accommodation space (3), a first conveyor (30) for circulating the air inside the container (1) between the storage space (3) and the air passage (19); a heat exchanger (29) disposed in the air passage (19); a detector (110a) disposed below the heat exchanger (29) and configured to detect refrigerant leaking into the container (1); a casing (50, 111) that houses the detection part (110a), The air passage (19) is formed by the first conveyor (30) so that air flows from above to below, the casing (50, 111) has a first opening (51) and a second opening (52) that connect the detection portion (110a) and the air passage (19); the first opening (51) opens in a direction perpendicular to the air flow in the air passage (19) or toward the downstream side of the air flow, the second opening (52) opens toward the upstream side of the air flow in the air passage (19), the first conveyor (30) is disposed in the air passage (19); the first opening (51) and the second opening (52) are disposed below the first conveyor (30); The density of the refrigerant is greater than the density of air. Refrigeration equipment for containers.

3. a pressure reducing section (120) disposed in the air passage (19) and configured to reduce the pressure acting on the first opening (51) due to the air conveyed by the first conveyer (30).

3. A container refrigeration system according to claim 1 or 2.

4. The casing (50, 111) has a receiving portion (53) between the second opening (52) and the detecting portion (110a) for receiving water that has flowed from the air passage (19) into the second opening (52).

3. A container refrigeration system according to claim 1 or 2.

5. The casing (50, 111) has a discharge port (54) between the second opening (52) and the detection portion (110a) for discharging water that has flowed from the air passage (19) into the second opening (52) to the outside.

3. A container refrigeration system according to claim 1 or 2.

6. The casing (50, 111) has a cylindrical portion (62) in which the second opening (52) is formed and which communicates with the detection portion (110a).

3. A container refrigeration system according to claim 1 or 2.

7. The cylindrical portion (62) has a first cylindrical portion (62a) and a second cylindrical portion (62b) formed in this order toward the air passage (19), the second cylindrical portion (62b) is formed so that the cross-sectional area of ​​the flow path is larger than the cross-sectional area of ​​the flow path of the first cylindrical portion (62a); The second opening (52) is formed in the second cylindrical portion (62b).

7. A container refrigeration system according to claim 6.

8. The opening surface of the second opening (52) is formed to be inclined with respect to the air flow in the air passage (19), and includes a suppression portion (55) that suppresses the inflow of foreign matter contained in the air in the air passage (19).

3. A container refrigeration system according to claim 1 or 2.

9. A container refrigeration unit provided in a container (1) having a refrigerant circuit (R) that performs a refrigeration cycle, the container (1) having an interior partitioned into an accommodation space (3) and an air passage (19) communicating with the accommodation space (3), a first conveyor (30) for circulating the air inside the container (1) between the storage space (3) and the air passage (19); a heat exchanger (29) disposed in the air passage (19); a detector (110a) disposed below the heat exchanger (29) and configured to detect refrigerant leaking into the container (1); a casing (50, 111) that houses the detection part (110a), the casing (50, 111) has a first opening (51) that connects the detection portion (110a) to the air passage (19), and a third opening (73) that blows air sucked into the first opening (51) into the air passage (19), The first opening (51) opens in a horizontal direction or downward from the horizontal direction, The third opening (73) is disposed at the same height as or lower than the first opening (51). The casing (50, 111) is provided with a second conveyor (130) that sucks air from the air passage (19) into the first opening (51), The density of the refrigerant is greater than the density of air. Refrigeration equipment for containers.

10. A container refrigeration unit provided in a container (1) having a refrigerant circuit (R) that performs a refrigeration cycle, the container (1) having an interior partitioned into an accommodation space (3) and an air passage (19) communicating with the accommodation space (3), a first conveyor (30) for circulating the air inside the container (1) between the storage space (3) and the air passage (19); a heat exchanger (29) disposed in the air passage (19); a detector (110a) disposed below the heat exchanger (29) and configured to detect refrigerant leaking into the container (1); a casing (50, 111) that houses the detection part (110a), The air passage (19) is formed by the first conveyor (30) so that air flows from above to below, the casing (50, 111) has a first opening (51) that connects the detection portion (110a) to the air passage (19), and a third opening (73) that blows air sucked into the first opening (51) into the air passage (19), the first opening (51) opens in a direction perpendicular to the air flow in the air passage (19) or toward the downstream side of the air flow, the third opening (73) is disposed at the same height as or lower than the first opening (51); The casing (50, 111) is provided with a second conveyor (130) that sucks air from the air passage (19) into the first opening (51), The density of the refrigerant is greater than the density of air. Refrigeration equipment for containers.

11. The first conveyor (30) has a first electric motor (30b) that drives the first conveyor (30), the second conveyor (130) has a second electric motor (130a) that drives the second conveyor (130); The first electric motor (30b) and the second electric motor (130a) are supplied with electric power from different power sources. Container refrigeration system according to claim 9 or 10.

12. The second conveyor (130) sucks air at a height of 1 m or less from the bottom of the air passage (19) to the first opening (51). Container refrigeration system according to claim 9 or 10.

13. The container (1) has a wall (16a) separating the external space (5) from the air passage (19), The casing (50, 111) is provided on the wall (16a).

11. A container refrigeration system according to claim 1, 2, 9 or 10.

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