WO2007135957A1

WO2007135957A1 - Refrigeration device

Info

Publication number: WO2007135957A1
Application number: PCT/JP2007/060151
Authority: WO
Inventors: Satoru Sakae; Toshiaki Mukaidani
Original assignee: Daikin Industries, Ltd.
Priority date: 2006-05-18
Filing date: 2007-05-17
Publication date: 2007-11-29
Also published as: JP2007309586A; US20090188276A1; EP2019273A1; AU2007252631A1; CN101449118A; JP4082434B2; KR20090013222A

Abstract

A refrigeration device where a refrigeration expansion valve, a refrigeration heat exchanger, a compressor (11), and an outdoor heat exchanger are interconnected in sequence and that has a refrigerant circuit for performing a vapor compression refrigeration cycle. A suction pressure sensor (25) is attached to a suction tube (61) of the compressor (11) via heat absorption piping (90). The heat absorption piping (90) is connected to a discharge tube (64) of the compressor (11) via a heat transmission member (91). The length of the heat absorption piping (90) is set not less than a predetermined minimum length that is longer as the temperature of vapor in the refrigeration heat exchanger is lower.

Description

Specification

Refrigeration equipment

Technical field

TECHNICAL FIELD [0001] The present invention relates to a refrigeration apparatus including a refrigerant circuit that performs a vapor compression refrigeration cycle, and particularly relates to a suction pressure sensor mounting structure for measuring a suction pressure of a compression mechanism.

Conventionally, a refrigeration apparatus that includes a refrigerant circuit that performs a refrigeration cycle and that performs refrigeration or freezing in a warehouse is known (for example, Patent Document 1).

[0003] In the refrigeration apparatus of Patent Document 1, a refrigeration cooling heat exchanger, a low-stage compressor, a high-stage compressor, an outdoor heat exchanger, and a refrigeration expansion valve are sequentially connected. In the refrigerant circuit, the refrigerant compressed in two stages by the low-stage compressor and the high-stage compressor dissipates heat in the outdoor heat exchanger to be condensed. The liquefied refrigerant is expanded by the refrigeration expansion valve and flows through the refrigeration cooling heat exchanger, absorbs heat from the internal air, evaporates at −30 ° C., and cools the internal temperature to −20 ° C. . Then, the evaporated refrigerant is again sucked into the low-stage compressor, and thereafter this circulation is repeated.

Patent Document 1: Japanese Patent Laid-Open No. 2004-353996

Disclosure of the invention

Problems to be solved by the invention

[0004] Incidentally, in the refrigeration apparatus of Patent Document 1, suction pressure sensors for measuring the suction pressure of the compressors are provided in the suction pipes of the low-stage and high-stage compressors.

Specifically, as shown in FIG. 5, a narrow tube (c) is connected to the suction pipe (a) of the compressor, and a pressure sensor (b) is connected to the end of the thin pipe (c). A male screw for connection is formed on the outer peripheral surface. On the other hand, the pressure sensor (b) includes a connection portion (d) having a female screw formed on the inner peripheral surface, and the female screw of the connection portion (d) is screwed into the male screw of the thin tube (c). Connected to the suction pipe (a).

[0006] Therefore, in the refrigeration apparatus, when the evaporation temperature in the cooling heat exchanger is 0 ° C or lower and the refrigerant having the temperature of 0 ° C or lower flows through the suction pipe (a), the pressure sensor (b) (C) and There was a risk that the water that entered the gaps between the screws of the screw would freeze and the connection part (d) of the sensor (b) could freeze and break.

[0007] Thus, conventionally, a measure has been taken to prevent moisture from entering by filling the gaps between the screws with silicon. However, since it takes a long time to dry the silicon, workability at the time of attachment is lowered, and there is a problem that reliability is lowered because of variations in the filling state of the silicon.

[0008] There is also a method in which the pressure sensor (b) is attached by brazing instead of screwing into the thin tube (c). However, this method has a problem in that maintainability deteriorates because it is necessary to recover the refrigerant when replacing the sensor (b).

[0009] As described above, there has been a problem that conventional freeze-fracture prevention measures are not sufficient in terms of workability and reliability.

[0010] The present invention has been made in view of the strong point, and in a refrigeration apparatus having a suction pressure sensor for measuring the suction pressure of the compression mechanism, improves workability when the pressure sensor is attached and replaced. It is an object to improve the reliability of the pressure sensor.

Means for solving the problem

[0011] A first invention includes a refrigerant circuit (10) in which an evaporator (16, 17), a compression mechanism (11), a condenser (13), and an expansion mechanism (15a, 15b) are sequentially connected. In addition, the refrigeration apparatus includes a suction pressure sensor (25) for measuring the suction pressure of the compression mechanism (11), the suction pressure sensor (25) being a suction device of the compression mechanism (11). The pipe (61) is connected via an endothermic pipe (90) for making the temperature of the connection part (25b) of the suction pressure sensor (25) higher than the temperature of the suction pipe (61).

[0012] In the first aspect of the invention, since the refrigerant flowing through the evaporator (16, 17) flows through the suction pipe (61), the set temperature of the evaporator (16, 17) is low (0 ° C or lower), a low-temperature refrigerant of 0 ° C or lower also flows through the suction pipe (61) of the compressor mechanism (11). Therefore, according to the first aspect of the present invention, by attaching the pressure sensor (25) via the heat absorption pipe (90), the cold heat of the refrigerant flowing through the suction pipe (61) is converted to the connection part ( 25b) and the heat absorption pipe (90) absorbs heat from ambient air, etc. The connection (25b) of the sensor (25) is set to a temperature higher than 0 ° C to prevent freezing of the connection (25b).

[0013] A second invention is the heat absorption pipe (90) according to the first invention, wherein the temperature of the connection part (25b) of the suction pressure sensor (25) depends on the ambient temperature. ) It is formed in a length that raises the temperature further.

[0014] In the second aspect of the invention, the heat absorption pipe (90) absorbs heat from the surrounding air, and gradually rises from the suction pipe (61) to the connection portion (25b) of the suction pressure sensor (25). Warm the connection part (25b) of the suction pressure sensor (25) to a temperature higher than 0 ° C.

[0015] In a third aspect based on the second aspect, the minimum length of the endothermic pipe (90) is a predetermined set length that increases as the evaporation temperature of the evaporator (16, 17) decreases. Is set.

[0016] In the third aspect of the invention, as the evaporation temperature of the evaporator (16, 17) decreases, the temperature of the refrigerant flowing through the suction pipe (61) decreases. Therefore, by increasing the minimum length of the heat absorption pipe (90) as the evaporation temperature of the evaporator (16, 17) decreases, as the temperature of the refrigerant flowing through the suction pipe (61) decreases, This cold heat of the refrigerant is made difficult to be transmitted to the connection part (25b) of the suction pressure sensor (25). On the other hand, by increasing the area of the endothermic pipe (90), the endothermic amount of heat absorbed by the endothermic pipe (90) is increased.

[0017] In a fourth aspect based on any one of the first to third aspects, the heat absorption pipe (90) is connected to the high pressure side pipe (64) of the refrigerant circuit (10) by a heat transfer member (91). ) Is attached through.

[0018] In the fourth invention, the heat of the high-pressure side pipe (64) is transferred through the heat transfer member (91), thereby increasing the heat absorption amount of the heat-absorbing pipe (90). The connection (25b) of the pressure sensor (25) is higher than 0 ° C and the temperature.

[0019] The high-pressure side pipe (64) in the fourth aspect of the invention is a pipe through which the refrigerant flowing through the suction pipe (61) flows at a pressure higher than 0 ° C and flows through the refrigerant! Uh.

In a fifth aspect based on the fourth aspect, the high-pressure side pipe (64) is the discharge pipe (64) of the compression mechanism (11).

[0021] The heat absorption amount received by the heat absorption pipe (90) from the high pressure side pipe (64) via the heat transfer member (91) increases as the temperature of the high pressure side pipe (64) increases. Therefore, in the fifth aspect of the present invention, the heat absorption pipe (90) is disposed via the discharge pipe (64) and the heat transfer member (91) of the high-temperature compression mechanism (11). By connecting, the endothermic amount of the endothermic pipe (90) is surely increased.

The invention's effect

[0022] According to the first aspect of the present invention, the heat absorption pipe (90) makes it difficult for cold heat of the refrigerant flowing through the suction pipe (61) to be transmitted to the connection part (25b) of the suction pressure sensor (25). At the same time, the heat absorption pipe (90) can absorb heat from the surrounding air. As a result, even when the set temperature of the evaporator (16, 17) is low and a low-temperature refrigerant of 0 ° C or less flows through the suction pipe (61), the connection part (25b) of the suction pressure sensor (25) is The temperature can be higher than 0 ° C. As a result, freezing damage to the connection portion (25b) of the suction pressure sensor (25) can be prevented, and the reliability of the suction pressure sensor (25) is improved.

[0023] In addition, since it is possible to prevent damage without filling with silicon or brazing, workability when installing and replacing the suction pressure sensor (25) is improved compared to conventional measures to prevent damage. To do.

[0024] Further, according to the second aspect of the invention, the endothermic pipe (90) is connected to the inlet pipe (61) from the inlet pipe (61) depending on the temperature of the connecting portion (25b) of the inlet pressure sensor (25). The heat absorption pipe (90) absorbs the surrounding aerodynamic force because it is formed to rise in temperature, and the heat absorption pipe (90) is connected from the suction pipe (61) to the connection part of the suction pressure sensor (25) ( The temperature can be gradually raised over 25b). As a result, the connection part (25b) of the suction pressure sensor (25) can be set to a temperature higher than 0 ° C.

[0025] According to the third invention, the minimum length of the endothermic pipe (90) is set to the evaporator.

(16, 17) is set to a predetermined set length that becomes longer as the evaporation temperature becomes lower.As the temperature of the refrigerant flowing through the intake pipe (61) becomes lower, the cold heat of this refrigerant is reduced to the suction pressure sensor (25 ) Can be transmitted to the connection part (25b). At the same time, by increasing the area of the endothermic pipe (90), it is possible to increase the amount of heat absorbed by the endothermic pipe (90) by absorbing heat such as ambient air. As a result, according to the set temperature of the evaporator (16, 17), the connection part (25b) of the suction pressure sensor (25) can be surely set to a temperature higher than 0 ° C.

[0026] According to the fourth aspect of the invention, the heat absorption pipe (90) absorbs the heat of the high pressure side pipe (64) of the refrigerant circuit (10) via the heat transfer member (91). Therefore, the endothermic amount of the endothermic pipe (90) can be increased. As a result, the suction pressure sensor (25) The connection (25b) can be brought to a temperature higher than 0 ° C.

[0027] According to the fifth aspect of the invention, the heat absorption pipe (90) can absorb the heat of the discharge pipe (64) of the compression mechanism (11) via the heat transfer member (91). Therefore, since the discharge pipe (64) of the compression mechanism (11) is at a high temperature, the heat absorption amount of the heat absorption pipe (90) can be reliably increased. As a result, the connection part (25b) of the suction pressure sensor (25) can be surely brought to a temperature higher than 0 ° C.

Brief Description of Drawings

FIG. 1 is a piping system diagram showing a refrigerant circuit of a refrigeration apparatus according to an embodiment.

FIG. 2 is a schematic perspective view showing a suction pressure sensor mounting structure according to the embodiment.

FIG. 3 is a relationship diagram showing a relationship between the evaporation temperature of the refrigeration heat exchanger according to the embodiment and the length of the endothermic pipe.

[Fig. 4] Fig. 4 is a piping system diagram showing a refrigerant circulation direction during the cooling operation of the refrigeration apparatus according to the embodiment.

FIG. 5 is a schematic configuration diagram showing a conventional suction pressure sensor mounting structure. Explanation of symbols

1 Refrigeration equipment

10 Refrigerant circuit

11 Compressor (compression mechanism)

13 Outdoor heat exchange (condenser)

25 Suction pressure sensor

25a connection

61 Suction tube

64 Discharge pipe (high-pressure side pipe)

90 Endothermic piping

91 Heat transfer member

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the embodiment of the present invention is a refrigeration apparatus (1) for cooling a cooling chamber, comprising an outdoor unit (2), a refrigeration unit (3), and a controller (100). ing. The outdoor unit (2) is installed outdoors, while the refrigeration unit (3) is installed in a cooling room.

[0032] The refrigeration apparatus (1) is provided with an outdoor circuit (20) in the outdoor unit (2), and a refrigerator internal circuit (30) in the refrigeration unit (3). ing. In the refrigeration apparatus (1), the gas end side of the outdoor circuit (20) and the gas end side of the refrigerator internal circuit (30) are connected by a gas side communication pipe (22), while the outdoor circuit ( The liquid end side of 20) and the liquid end side of the refrigerator internal circuit (30) are connected by a liquid side connecting pipe (21) to constitute a refrigerant circuit (10) of a vapor compression refrigeration cycle.

[0033] <Outdoor unit>

The outdoor circuit (20) of the outdoor unit (2) includes a compressor (11), an outdoor heat exchanger (13), a receiver (14), an outdoor expansion valve (45), a refrigerant heat exchanger ^^ (50) A branch expansion valve (46) is provided. Further, the outdoor circuit (20) is provided with a four-way switching valve (12), a liquid side closing valve (53), and a gas side closing valve (54). In this outdoor circuit (20), one end of the liquid side connecting pipe (21) is connected to the liquid side closing valve (53), and one end of the gas side connecting pipe (22) is connected to the gas side closing valve (54). One end is connected to each other!

[0034] The compressor (11) is a scroll compressor, and is configured such that the operation capacity is variable by inverter control. One end of the suction pipe (61) is connected to the suction side of the compressor (11), and the other end of the suction pipe (61) is connected to the four-way switching valve (12). One end of a discharge pipe (64) is connected to the discharge side of the compressor (11), and the other end of the discharge pipe (64) is connected to the four-way switching valve (12).

[0035] The outdoor heat exchange (13) is a cross fin type fin 'and' tube type heat exchange.

In this case, heat exchange is performed between the refrigerant and the outdoor air, and the condenser is configured. One end of the outdoor heat exchange (13) is connected to the four-way switching valve (12). On the other hand, the other end of the outdoor heat exchanger (13) is connected to the top of the receiver (14) via the first liquid pipe (81). The first liquid pipe (81) is provided with a check valve (CV-1) that allows only the refrigerant to flow from the outdoor heat exchanger (13) to the receiver (14). At the bottom of the receiver (14) One end of the second liquid pipe (82) is connected.

[0036] The refrigerant heat exchanger (50) is a plate heat exchanger that exchanges heat between the refrigerant and the refrigerant. The first flow path (50a) and the second flow path ( 50b). The other end of the second liquid pipe (82) is connected to the inlet side of the first flow path (50a) of the refrigerant heat exchanger (50), and the outlet side of the first flow path (50a) is connected to the first flow path (50a). One end of the three-liquid pipe (83) is connected. The other end of the third liquid pipe (83) is connected to one end of the liquid side connecting pipe (21) via the liquid side closing valve (53). The third liquid pipe (83) is provided with a check valve (CV-2) that allows only the flow of directional refrigerant to the first flow path (50a) force liquid side shut-off valve (53), The

[0037] One end of the branch liquid pipe (84) is connected to the third liquid pipe (83) upstream of the check valve (CV-2), and the other end of the branch liquid pipe (84) is connected to the third liquid pipe (83). The refrigerant heat exchanger (50) is connected to the inlet side of the second flow path (50b). The branch liquid pipe (84) is provided with a branch expansion valve (46). The branch expansion valve (46) is an electronic expansion valve whose opening degree is adjustable.

[0038] The outlet side of the second flow path (50b) of the refrigerant heat exchanger (50) is connected to one end of an injection pipe (85). The other end of the injection pipe (85) is connected between the four-way switching valve (12) and the compressor (11) in the suction pipe (61).

[0039] In the third liquid pipe (83), one end of a fourth liquid pipe (88) is connected between the check valve (CV-2) and the liquid side stop valve (53). The other end of the fourth liquid pipe (88) is connected between the check valve (CV-1) and the receiver (14) in the first liquid pipe (81). The fourth liquid pipe (88) is provided with a check valve (CV-3) that allows only the flow of the refrigerant directed from the third liquid pipe (83) to the receiver (14).

[0040] One end of a fifth liquid pipe (89) is connected to the branch liquid pipe (84) between the third liquid pipe (83) and the branch expansion valve (46). The other end of the pipe (89) is connected between the other end of the outdoor heat exchanger (13) in the first liquid pipe (81) and the check valve (CV-1). The fifth liquid pipe (89) is provided with an outdoor expansion valve (45).

[0041] In the four-way switching valve (12), the first port is at the discharge pipe (64), the second port is at the suction pipe (61), and the third port is at one end of the outdoor heat exchange (13), The 4th port is connected to each gas side shutoff valve (54). The four-way selector valve (12) is in a first state (actually shown in FIG. 1) in which the first port and the third port communicate with each other and the second port and the fourth port communicate with each other. Switch between the first port and the fourth port and the second port and the third port (shown in broken lines in Fig. 1). It is configured to be possible.

[0042] The outdoor circuit (20) includes an oil separator (70) and an oil return pipe (71).

[0043] The oil separator (70) is provided in the discharge pipe (64) and separates the discharge gas power refrigerating machine oil of the compressor (11). One end of the first oil return pipe (71) is connected to the oil separator (70), and the other end of the first oil return pipe (71) is connected to the injection pipe (85) of the suction pipe (61). It is connected between the connection part and the compressor (11). The oil return pipe (71) is provided with a capillary tube (72) for adjusting the flow rate of the refrigerating machine oil.

[0044] Various sensors (19, 23, 24, 25, 51) and pressure switches (95a, 95b) are attached to the outdoor circuit (20). Specifically, the suction pipe (61) of the compressor (11) has a suction temperature sensor (24) and a connection between the connection of the injection pipe (85) and the connection of the oil return pipe (71). A suction pressure sensor (25) is provided in order. As will be described in detail later, the suction pressure sensor (25) is connected to the suction pipe (61) via a heat absorption pipe (90) as a feature of the present invention. A discharge pressure sensor (23) and a discharge temperature sensor (19) are provided on the discharge side of the compressor (11). A temperature sensor (51) is provided on the outlet side of the first flow path (50a) of the refrigerant heat exchanger (50).

[0045] The outdoor unit (2) is provided with an outdoor air temperature sensor (13a) and an outdoor fan (13f). Outdoor air is sent to the outdoor heat exchanger (13) by this outdoor fan (13f).

[0046] <Refrigerated unit>

The refrigerator internal circuit (30) of the refrigeration unit (3) is provided with two refrigeration heat exchangers (16, 17) and two drain pan heaters (26, 27).

[0047] Each of the refrigerated heat exchanges ^^ (16, 17) is the same cross fin type fin 'and' tube type heat exchange ^^, and heat exchange is performed between the refrigerant and the air in the cooling chamber. It is configured in the evaporator. One end of each refrigeration heat exchanger (16, 17) is connected to each refrigeration expansion valve (15a, 15b) via a pipe. On the other hand, one end of each gas side branch pipe (22a, 22b) is connected to the other end of each of the refrigeration heat exchangers (16, 17). The other ends of (22a, 22b) join together and are connected to the other end of the gas side connecting pipe (22).

[0048] Each of the refrigeration expansion valves (15a, 15b) is an electronic expansion valve configured to be adjustable in opening, and is configured as an expansion mechanism. Each refrigeration heat exchanger (16, 17) is provided with a first refrigerant temperature sensor (16b, 17b), and the other refrigeration heat exchanger (16, 17) has a second refrigerant at the other end. Temperature sensors (18a, 18b) are respectively provided. The first refrigerant temperature sensors (16b, 17b) measure the evaporation temperature of the refrigerant in the refrigeration heat exchanger (16, 17). During the cooling operation, the refrigeration expansion valve (15a, 15b) has a refrigerant evaporating temperature at which the measured temperature of the second refrigerant temperature sensor (18a, 18b) is measured by the first refrigerant temperature sensor (16b, 17b). The opening degree is adjusted so as to be higher than a predetermined temperature (for example, 5 ° C.).

[0049] The drain pan heaters (26, 27) are not shown in the figure, and are disposed in the drain pan, and prevent the drain pan from forming frost and generating ice by flowing a high-temperature and high-pressure refrigerant and heating the drain pan. It is. One end of each drain pan heater (26, 27) is connected to one end of each liquid side branch pipe (21a, 21b), and the other end of each liquid side branch pipe (21a, 21b) joins each other. It is connected to the other end of the liquid side communication pipe (21). On the other hand, the other end of the drain pan heater (26, 27) is connected to one end of the refrigeration expansion valve (15a, 15b).

[0050] The refrigeration unit (3) is provided with cooling room temperature sensors (16a, 16b) and cooling room fans (16f, 17f). Air in the cooling chamber is sent to the refrigeration heat exchangers (16, 17) by the fans (16f, 17f) in the cooling chamber.

[0051] <Controller>

The controller (100) performs switching and opening adjustment of various valves provided in the refrigerant circuit (10) to control a cooling operation operation for maintaining the cooling chamber at a set temperature, and for controlling the cooling chamber. The defrosting operation is controlled.

Next, the attachment structure of the suction pressure sensor (25), which is a feature of the present invention, will be described in more detail based on FIGS.

[0053] During the cooling operation of the refrigeration system (1), since the refrigerant evaporated in the refrigeration heat exchanger (16, 17) flows through the suction pipe (61), the refrigerant evaporation temperature in the refrigeration heat exchanger (16, 17) Low inhalation If the temperature of the refrigerant flowing through the pipe (61) is 0 ° C or lower, the connection part (25b) of the suction pressure sensor (25) may be frozen and damaged. Therefore, as a feature of the present invention, the suction pressure sensor (25) is connected to the suction pipe (61) of the compressor (11) via the heat absorption pipe (90) as shown in FIGS. Furthermore, the heat absorption pipe (90) is connected to the discharge pipe (64) of the compressor (11) by a heat transfer member (91).

That is, the heat absorption pipe (90) is for making the temperature of the connection part (25b) of the suction pressure sensor (25) higher than the temperature of the suction pipe (61).

Specifically, as shown in FIG. 2, one end of the endothermic pipe (90) is connected to the middle of the suction pipe (61) of the compressor (11). The heat-absorbing pipe (90) is formed with a pipe diameter thinner than that of the suction pipe (61) and a length of 20 cm, and is bent four times to be compact. Further, a male screw (not shown) is formed on the outer periphery of the other end of the heat absorption pipe (90). The suction pressure sensor (25) includes a sensor body (25a) and a connection portion (25b), and a female screw (not shown) is formed on the inner peripheral surface of the connection portion (25b). The suction pressure sensor (25) is attached to the heat absorbing pipe (90) by screwing the female screw of the connecting portion (25b) with the male screw at the other end of the heat absorbing pipe (90). ing. In addition, an L-shaped port tube (90a) having a gauge port (26) is connected to the other end of the heat absorption pipe (90).

[0056] As shown in Fig. 2, the heat transfer member (91) is formed in a plate shape having an L-shaped cross section.

One end of the heat transfer member (91) in the lateral direction is fixed to the downstream side of the oil separator (70) in the discharge pipe (64), while the other end is on the other end side of the heat absorption pipe (90) ( It is fixed to the connection part (25b) of the suction pressure sensor (25). The lower end side of the heat transfer member (91) is fixed to the port thin tube (90a). The heat transfer member (91) also has a function as a support member that supports the heat absorption pipe (90).

[0057] Next, the results of experiments on the length of the endothermic pipe (90) will be described with reference to FIG.

[0058] Fig. 3 shows the evaporating temperature of the refrigerated heat exchanger (16, 17) and the length of the endothermic pipe (90) at which the connection part (25b) of the suction pressure sensor (25) is 10 ° C. It is a figure which shows a relationship. In FIG. 3, pipe structure A is a structure in which the heat absorption pipe (90) is not connected by the discharge pipe (64) of the compressor (11) and the heat transfer member (91). Heat transfer pipe (90) and discharge pipe (64) Show the structure connected by member (91)!

[0059] In pipe structure A, the length of the endothermic pipe (90) at which the temperature of the connection part (25b) of the suction pressure sensor (25) is 10 ° C is the evaporation of the refrigeration heat exchange (16, 17). The temperature was 20cm at -10 ° C, 48cm at -30 ° C, and 57cm at -40 ° C. This is because the temperature of the refrigerant flowing through the suction pipe (61) decreases as the evaporation temperature of the refrigerated heat exchanger (16, 17) decreases, so the cold heat is used to connect the connection part (25b) of the suction pressure sensor (25). This is because it is necessary to increase the area of the heat absorption pipe (90) and increase the amount of heat absorbed by the heat absorption pipe (90) from the surrounding air.

[0060] On the other hand, in the piping structure B, the length of the endothermic pipe (90) at which the temperature of the connection part (25b) of the suction pressure sensor (25) is 10 ° C is refrigerated heat exchange (16, 17 ) Is 10cm at 10 ° C, 25cm at 30 ° C, and 32cm at 40 ° C. Like A, the length needs to be increased as the evaporation temperature decreases. At the same evaporation temperature, the length can be shortened compared to A. This is because the heat absorption pipe (90) can absorb heat from the discharge pipe (64) of the high-temperature compressor (11) via the heat transfer member (91), and therefore absorbs heat only from the surrounding air. This is because the endothermic amount of the endothermic pipe (90) can be increased with certainty.

[0061] The temperature of the connection part (25b) of the suction pressure sensor (25) may be higher than at least 0 degrees so as not to freeze the connection part (25b). The length to be considered was examined. This is because if the length of the endothermic pipe (90) is set to a length where the temperature of the connection (25b) is higher than 0 ° C, the evaporation temperature of the refrigeration heat exchanger (16, 17) will be This is because the temperature of the connecting part (25b) can be surely raised above 0 ° C even if it temporarily falls due to fluctuations in the cooling load. Thus, considering the load fluctuation of the refrigeration system (1), the minimum length of the heat absorption pipe (90) was set to the length shown in FIG.

[0062] In this embodiment, as will be described later, the evaporation temperature of the refrigeration heat exchanger (16, 17) is

-Since it is 10 ° C, the endothermic pipe (90) needs to be 10cm or more in piping structure B. Therefore, the endothermic pipe (90) is formed to a length of 20 cm, which is an arbitrary length of 10 cm or more. [0063] Driving operation

Next, the operation during the cooling operation of the refrigeration apparatus (1) of the present embodiment will be described based on FIG.

[0064] During the cooling operation of the refrigeration system (1), as shown in Fig. 4, the four-way selector valve (12) of the outdoor circuit (20) is set to the first state by the control of the controller (100). The outdoor expansion valve (45) is fully closed. In this state, the compressor (11) is operated, the refrigeration expansion valves (15a, 15b) and the branch expansion valve (46) are appropriately controlled in opening degree, and the refrigerant circulates in the direction indicated by the solid line arrow in FIG. . The set temperature of the cooling chamber in this cooling operation is, for example, 2 ° C.

The refrigerant discharged from the compressor (11) is sent from the discharge pipe (64) to the outdoor heat exchanger (13) through the four-way switching valve (12). In the outdoor heat exchanger (13), the refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (13) flows through the first liquid pipe (81), passes through the receiver (14), flows into the second liquid pipe (82), and enters the refrigerant heat exchanger (50 ) In the first flow path (50a). . The liquid refrigerant that has flowed through the first flow path (50a) flows through the third liquid pipe (83), and a part of the refrigerant is used as a branching refrigerant as shown by the broken line arrow in FIG. , Is decompressed by the branch expansion valve (46), and flows into the second flow path (50b) of the refrigerant heat exchanger (50). As a result, the liquid refrigerant flowing through the first flow path (50a) exchanges heat with the branched refrigerant flowing through the second flow path (50b) .For example, after being cooled to 15 ° C, the third liquid pipe ( 83) flows through the liquid side connecting pipe (21) via the liquid side shut-off valve (53) and flows into the refrigerator circuit (30). Further, the branched liquid refrigerant in the second flow path (50b) evaporates and is indicated to the suction pipe (61) of the compressor (11) through the instruction pipe (85).

[0066] In the refrigerator internal circuit (30), the liquid refrigerant power at 15 ° C is diverted to the liquid side branch pipes (21a, 21b), flows through the drain pan heaters (26, 27), and the drain pans (56, 57) Prevent frost formation.

[0067] The liquid refrigerant that has also drained the drain pan heater (26, 27) is decompressed and expanded when passing through each refrigeration expansion valve (15a, 15b) and introduced into each refrigeration heat exchanger (16, 17). Is done. In each of the refrigeration heat exchangers (16, 17), the refrigerant absorbs heat from the air in the cooling chamber and evaporates at an evaporation temperature of, for example, 10 ° C. In the refrigeration unit (3), the air cooled by the refrigeration heat exchanger (16, 17) is supplied into the cooling chamber, and the temperature in the cooling chamber is maintained at the set temperature of 2 ° C. [0068] The refrigerant that has flowed through each of the refrigeration heat exchangers (16, 17) flows through the gas side branch pipes (22a, 22b), and then joins in the gas side communication pipe (22). Thereafter, the gas refrigerant flows through the gas side connecting pipe (22), flows through the suction pipe (61) through the four-way switching valve (12), and is sucked into the compressor (11) and compressed.

[0069] Here, the refrigerant of about 10 ° C evaporated in the refrigeration heat exchanger (16, 17) flows through the suction pipe (61). In the present invention, the suction pressure sensor (25) is endothermic. It is connected to the suction pipe (61) via the pipe for piping (90), and further connected to the heat absorption pipe (90), the discharge pipe (64) of the compressor (11) and the heat transfer member (91). Therefore, the connection part (25b) of the suction pressure sensor (25) is not frozen and damaged. Furthermore, as shown in Fig. 3, if the evaporation temperature of the refrigerated heat exchanger (16, 17) is 23 ° C or higher, the temperature of the connection part (25b) of the suction pressure sensor (25) is reliably 10 ° C. As described above, even when the cooling load fluctuates during the cooling operation, the connecting portion (25b) can be surely brought to a temperature higher than 0 ° C.

[0070] The refrigeration apparatus (1) is configured to perform the defrosting operation by temporarily stopping the cooling operation. The operation during the defrosting operation is not shown, but the four-way selector valve (12) is set to the second state, the refrigeration expansion valves (15a, 15b) are fully open, and the branch expansion valve (46) is fully closed. Thus, the outdoor expansion valve (45) is appropriately controlled, and reverse cycle defrost is performed in which the refrigerant circulates in the reverse direction to that during the cooling operation.

[0071] Specifically, the discharged gas refrigerant of the compressor (11) flows through each refrigeration heat exchanger (16, 17) and each drain pan heater (26, 27), and each refrigeration heat exchange (16, 17) The frost adhering to the drain pan dissipates heat and condensates and flows through the fourth liquid pipe (88) of the outdoor circuit (20). Thereafter, the refrigerant flows through the liquid side communication pipe (21) and is introduced into the outdoor circuit (20), and then flows through the fourth liquid pipe (88), and the refrigerant heat exchange (50) between the receiver (14) and the refrigerant (50). It flows through one channel (50a). Then, when the refrigerant flows through the fifth liquid pipe (89), the refrigerant is expanded by the outdoor expansion valve (45), condensed by the outdoor heat exchanger (13), and sucked into the compressor (11).

[0072] Effects of one embodiment

In the refrigeration apparatus (1), the heat absorption pipe (90) can make it difficult to transmit the cold heat of the refrigerant flowing through the suction pipe (61) to the connection part (25b) of the suction pressure sensor (25). The heat absorption pipe (90) can absorb the surrounding air and discharge pipe (64) force. this As a result, when the refrigerant at 10 ° C evaporated by refrigeration heat exchange (16, 17) flows through the suction pipe (61), the connection part (25b) of the suction pressure sensor (25) is higher than 0 ° C. Temperature. As a result, freezing damage to the connection portion (25b) of the suction pressure sensor (25) can be prevented, and the reliability of the suction pressure sensor (25) is improved. Further, since damage can be prevented without filling with silicon or brazing, workability at the time of installing and replacing the suction pressure sensor (25) is improved as compared with the conventional damage prevention measures.

[0073] Further, since the heat absorption pipe (90) absorbs heat from the discharge pipe (64) of the refrigerant circuit (10) via the heat transfer member (91), the heat absorption pipe (90) absorbs heat. The amount of heat can be increased. Thereby, the connection part (25b) of the suction pressure sensor (25) can be set to a temperature higher than 0 ° C.

[0074] Further, since the heat absorption pipe (90) can absorb the heat of the discharge pipe (64) of the compression mechanism (11) via the heat transfer member (91), the compression mechanism (11) Since the discharge pipe (64) has a high temperature, the heat absorption amount of the heat absorption pipe (90) can be reliably increased. As a result, the connection part (25b) of the suction pressure sensor (25) can be surely brought to a temperature higher than 0 ° C.

[0075] << Other Embodiments >>

For the above embodiment, the following configuration may be used.

In the refrigeration apparatus (1) of the above embodiment, the heat absorption pipe (90) is formed to a length of 20 cm and is further connected by the discharge pipe (64) and the heat transfer member (91). 91) It is possible to prevent freezing only by forming the endothermic pipe (90) to a predetermined length. That is, as shown in Fig. 3, even in the piping structure A where the endothermic pipe (90) is not connected to the discharge pipe (64), the length of the endothermic pipe (90) is If the set length is set to be longer as the evaporation temperature is lower, such as 20 cm or more and 48 cm or more at -30 ° C, the connection part (25b) of the suction pressure sensor (25) should be 10 ° C or more. can do . Therefore, if the length of the endothermic pipe (90) is set to be longer than this length, the connecting part (25b) that connects the endothermic pipe (90) to the discharge pipe (64) can be reliably Freezing damage can be prevented by raising the temperature.

[0077] That is, the endothermic pipe (90) is connected to the temperature of the connection (25b) of the suction pressure sensor (25). The degree may be such that the temperature rises from the suction pipe (61) according to the ambient temperature. The minimum length of the endothermic pipe (90) may be set to a predetermined set length that becomes longer as the evaporation temperature of the evaporator (16, 17) becomes lower.

In this case, the endothermic pipe (90) may be installed at any position! /, For example, the endothermic pipe (90) is located near the discharge pipe (64). If installed in this manner, the heat of the high-temperature discharge pipe (64) is transmitted through the air, and the amount of heat absorption can be further increased.

[0079] In the above embodiment, the length of the endothermic pipe (90) shown in Fig. 3 is merely an example, and the length of the endothermic pipe (90) is the same as that of the endothermic pipe (90). It is preferable to set the temperature appropriately depending on the ambient temperature conditions, the heat conductivity of the heat transfer member (91), the temperature of the discharge pipe (64) of the compressor (11), and the like. If the evaporation temperature of the evaporator (16, 17), where the cooling load fluctuation of the refrigeration system (1) is small, the length of the heat absorption pipe (90) is connected to the suction pressure sensor (25). The temperature of the part (25b) may be set to a length that becomes, for example, 1 ° C.

[0080] In addition, the refrigeration apparatus (1) of the above embodiment has performed a refrigeration cycle in which the refrigerant is compressed by one stage. It is also possible to perform a refrigeration cycle that compresses the two stages. In that case, since the temperature of the refrigerant flowing through the suction pipe of the low-stage compressor becomes very low, even if a pressure sensor for measuring the pressure of this low-temperature refrigerant is attached to the suction pipe via the heat absorption pipe. Good. Further, the heat absorption pipe may be connected to the high pressure side pipe of the refrigerant circuit or the discharge pipe through which the refrigerant discharged from the low stage compressor flows through a heat transfer member.

[0081] A refrigeration circuit in which a refrigeration heat exchanger and a low-stage compressor are connected to an outdoor circuit having a high-stage compressor, and a refrigeration circuit having a refrigeration heat exchanger Are connected in parallel, and both the high-stage compressor and the low-stage compressor suck in refrigerant at 0 ° C or less, the suction pressure sensor of the suction pipe of each compressor is connected via the heat absorption pipe. It may be connected.

In the refrigeration apparatus (1) of the above embodiment, the endothermic pipe (90) is connected to the discharge pipe (64) of the compressor, but is connected to the other high-pressure side pipe of the refrigerant circuit (10). May be. Specifically, the first to third liquid pipes (81, 82, 83) are exemplified.

In the refrigeration apparatus (1) of the above embodiment, the compression mechanism (11) is composed of one compressor (11). However, the compression mechanism (11) may be composed of a plurality of compressors connected in parallel.

[0084] The above embodiment is essentially a preferable example, and is not intended to limit the scope of the present invention, its application, or its use.

Industrial applicability

[0085] As described above, the present invention is useful for a refrigeration apparatus including a suction pressure sensor that measures the suction pressure of a compression mechanism.

Claims

The scope of the claims

[1] A refrigerant circuit (10) in which an evaporator (16, 17), a compression mechanism (11), a condenser (13), and an expansion mechanism (15a, 15b) are sequentially connected is provided. A refrigeration apparatus equipped with a suction pressure sensor (25) for measuring the suction pressure of 11),

The suction pressure sensor (25) makes the temperature of the connection (25b) of the suction pressure sensor (25) higher than the temperature of the suction pipe (61) in the suction pipe (61) of the compression mechanism (11). Connected via the endothermic pipe (90) for!

A refrigeration apparatus characterized by that.

[2] In claim 1,

The heat absorption pipe (90) is formed in such a length that the temperature of the connection part (25b) of the suction pressure sensor (25) rises from the suction pipe (61) due to the ambient temperature.

A refrigeration apparatus characterized by that.

[3] In claim 2,

The minimum length of the endothermic pipe (90) is set to a predetermined set length that increases as the evaporation temperature of the evaporator (16, 17) decreases.

A refrigeration apparatus characterized by that.

[4] In claim 1,

The heat absorption pipe (90) is attached to the high pressure side pipe (64) of the refrigerant circuit (10) via a heat transfer member (91).

A refrigeration apparatus characterized by that.

[5] In claim 4,

The high-pressure side pipe (64) is a discharge pipe (64) of the compression mechanism (11).

A refrigeration apparatus characterized by that.