Automatic switching device for refrigerant recovery operation and refrigerant recovery device

Abstract

The present invention comprises: a high pressure connection port that communicates with a high pressure-side connection opening of a high pressure-side pipe of a refrigeration cycle device; a low pressure connection port that communicates with a low pressure-side connection opening of a low pressure-side pipe of the refrigeration cycle device; a suction connection port that connects to a suction opening of a recovery machine; a discharge connection port that connects to a discharge opening of the recovery machine; a liquid connection port that connects to a liquid opening of a cylinder; a gas connection port that connects to a gas opening of the cylinder; a switching unit that switches between a flow passage of a liquid recovery mode in which liquid refrigerant within the refrigeration cycle device is recovered and a flow passage of a gas recovery mode in which gas refrigerant within the refrigeration cycle device is recovered; and a control device that performs the switching of the flow passage of the switching unit. The control device includes: a determination unit that determines a switch from the gas recovery mode to the liquid recovery mode on the basis of the temperature of a liquid reservoir of the refrigeration cycle device; and a switching processing unit that performs a flow passage switching process of the switching unit.

Description

Technical Field

[0001] This disclosure relates to a refrigerant recovery operation automatic switching device and a refrigerant recovery device that switch the refrigerant recovery operation when recovering refrigerant in a refrigerant recovery device such as a refrigeration cycle device.

Background Art

[0002] Refrigeration cycle devices such as refrigerators or air conditioners circulate the refrigerant enclosed in the refrigerant circuit to exchange heat with fluids such as air or water, and perform an operation of heating or cooling the fluid. Here, there are types of refrigerants with a high global warming potential. When such refrigerants are released into the atmosphere, they cause global warming and the like. Therefore, when moving a refrigeration cycle device in which refrigerant is enclosed or replacing equipment, etc., it is necessary to recover the refrigerant so as not to release it into the atmosphere. Thus, a refrigerant recovery device for recovering refrigerant from a refrigerant recovery device such as a refrigeration cycle device has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There are two methods for recovering refrigerant from refrigerant recovery devices, such as refrigeration cycle systems, using a refrigerant recovery device: liquid recovery, which recovers liquid refrigerant, and gas recovery, which recovers gaseous refrigerant. The following explanation assumes that the refrigerant recovery device is a refrigeration cycle system. Gas recovery allows for the recovery of all refrigerant in the refrigeration cycle system in a single procedure. For this reason, gas recovery is often used. However, gas recovery is time-consuming because the refrigerant recovery device stops if the temperature and pressure of the recovery cylinder rise, and because refrigerant stagnation into the refrigerant oil occurs when the temperature of the accumulator in the refrigeration cycle system drops, making it difficult for the refrigerant to evaporate.

[0005] On the other hand, liquid recovery can shorten the recovery time compared to gas recovery. However, the gaseous refrigerant that ultimately remains in the refrigerant circuit of the refrigeration cycle system cannot be recovered by liquid recovery. For this reason, it is necessary to switch from liquid recovery to gas recovery. However, the connection method of the connecting hoses that connect to the refrigerant circuit differs between liquid recovery and gas recovery. Also, reconnecting the connecting hoses requires refrigerant recovery and vacuuming of the hoses. This makes the work performed by the operator more complicated and increases the recovery time. Furthermore, there is a possibility of errors occurring during the work. In addition, since the operator is responsible for switching from liquid recovery to gas recovery, the operator needs to monitor the timing of the switch. For this reason, the workload on the operator was significant.

[0006] Furthermore, if gas recovery is continued while liquid refrigerant is present in liquid storage containers that are difficult to recover, such as accumulators, which are components of the refrigeration cycle system, the temperature and pressure in the refrigerant circuit will decrease, slowing down the refrigerant recovery speed and increasing the time required for recovery. To improve the refrigerant recovery speed, it is effective to switch from gas recovery to liquid recovery to restore the pressure that has dropped. However, the switch from gas recovery to liquid recovery was performed manually by the operator. As a result, the operator had to constantly monitor the temperature of the refrigerant circuit during gas recovery operation, which placed a heavy burden on the operator.

[0007] Therefore, the objective is to realize an automatic refrigerant recovery operation switching device and a refrigerant recovery device that can easily and automatically recover refrigerant while shortening the recovery time. [Means for solving the problem]

[0008] The refrigerant recovery operation automatic switching device relating to this disclosure is a refrigerant recovery operation automatic switching device that switches the flow path of refrigerant when recovering refrigerant in a refrigeration cycle device into a cylinder by driving a recovery machine, and comprises a high-pressure connection port that communicates with a high-pressure side connection port of the high-pressure side piping of the refrigeration cycle device, a low-pressure connection port that communicates with a low-pressure side connection port of the low-pressure side piping of the refrigeration cycle device, an intake connection port that connects to the intake port of the recovery machine, an intake connection port that connects to the discharge port of the recovery machine, a liquid connection port that connects to the liquid port of the cylinder, and a gas connection port that connects to the gas port of the cylinder, and in the liquid recovery mode for recovering liquid refrigerant in the refrigeration cycle device, the gas connection port and the intake connection port are connected. The device comprises a flow path that connects the discharge connection port and the low-pressure connection port, and connects the high-pressure connection port and the liquid connection port, and a switching unit that switches to a flow path that connects the high-pressure connection port and the low-pressure connection port and the suction connection port, and connects the discharge connection port and the liquid connection port in a gas recovery mode for recovering gaseous refrigerant in the refrigeration cycle device, and a control device that switches the flow path in the switching unit, the control device having a determination unit that determines to switch from gas recovery mode to liquid recovery mode when it determines that the temperature in the liquid reservoir of the refrigeration cycle device is lower than a set temperature, and a switching processing unit that performs the switching of the flow path in the switching unit when the determination unit determines to switch.

[0009] Furthermore, the refrigerant recovery device disclosed herein comprises the above-mentioned automatic refrigerant recovery operation switching device and recovery machine. [Effects of the Invention]

[0010] As described above, the refrigerant recovery operation automatic switching device and refrigerant recovery device disclosed can switch between gas recovery and liquid recovery simply by switching a switching valve. Therefore, refrigerant recovery using both gas and liquid recovery can be easily performed. As a result, there is no need to reconnect connection hoses, which shortens the recovery work time and reduces the release of refrigerant into the atmosphere. In addition, the high-pressure connection port and low-pressure connection port are in communication with the refrigeration cycle device, and refrigerant can be recovered using the high-pressure connection port and low-pressure connection port. As a result, the refrigerant recovery speed in gas recovery can be increased and the recovery time can be further shortened. Furthermore, since the switching from gas recovery to liquid recovery can be performed automatically based on the temperature of the liquid reservoir in the refrigeration cycle device, there is no need for workers to continuously check, which reduces the workload on workers. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows the configuration of a refrigerant recovery system centered on the refrigerant recovery operation automatic switching device 100 according to Embodiment 1. [Figure 2] This figure shows the fluid flow relationship in the gas recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 1. [Figure 3] This figure shows the fluid flow relationship in the liquid recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 1. [Figure 4] This figure illustrates the time change in the amount of refrigerant recovered due to mode switching according to Embodiment 1. [Figure 5] This diagram shows the control flow during automatic refrigerant recovery operation of the automatic refrigerant recovery operation switching device 100 according to Embodiment 1. [Figure 6] This diagram shows the configuration of a refrigerant recovery system centered on the refrigerant recovery operation automatic switching device 100 according to Embodiment 2. [Figure 7] This figure shows the fluid flow relationship in the gas recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 2. [Figure 8]It is a diagram showing the fluid flow relationship in the liquid recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 2. [Figure 9] It is a diagram showing the configuration of a refrigerant recovery system centered around the refrigerant recovery operation automatic switching device 100 according to Embodiment 3. [Figure 10] It is a diagram showing the fluid flow relationship in the gas recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 3. [Figure 11] It is a diagram showing the fluid flow relationship in the liquid recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 3. [Figure 12] It is a diagram showing the configuration of a refrigerant recovery system centered around the refrigerant recovery operation automatic switching device 100 according to Embodiment 4. [Figure 13] It is a diagram showing the fluid flow relationship in the gas recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 4. [Figure 14] It is a diagram showing the fluid flow relationship in the liquid recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 4. [Figure 15] It is a diagram showing the configuration of a refrigerant recovery system centered around the refrigerant recovery device 110 according to Embodiment 5. [Figure 16] It is a diagram showing the fluid flow relationship in the gas recovery mode of the refrigerant recovery device 110 according to Embodiment 5. [Figure 17] It is a diagram showing the fluid flow relationship in the liquid recovery mode of the refrigerant recovery device 110 according to Embodiment 5.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, a refrigerant recovery operation automatic switching device and the like according to an embodiment will be described with reference to the drawings and the like. In the following drawings, those denoted by the same reference numerals are the same or corresponding ones, and this shall be common throughout the entire text of the embodiment described below. Also, in the drawings, the relationship of the sizes of each component may be different from the actual ones. And the forms of the components shown throughout the specification are merely examples and are not limited to the forms described in the specification. In particular, the combinations of components are not limited to the combinations in each embodiment, and the components described in other embodiments can be applied to other embodiments. Also, regarding the high and low of pressure and temperature, they are not determined in relation to absolute values in particular, but are determined relatively in the states and operations of the device and the like. Also, for a plurality of similar devices distinguished by subscripts and the like, when there is no particular need to distinguish or specify them, the subscripts and the like may be omitted in the description.

[0013] Embodiment 1. FIG. 1 is a diagram showing the configuration of a refrigerant recovery system centered on a refrigerant recovery operation automatic switching device 100 according to Embodiment 1. The refrigerant recovery operation automatic switching device 100 is connected to an outdoor unit 200, a recovery machine 300, and a cylinder 400. The refrigerant recovery operation automatic switching device 100, the recovery machine 300, and the cylinder 400 are devices for recovering refrigerant, and the outdoor unit 200 is a device to be recovered with refrigerant.

[0014] The outdoor unit 200 is a device that constitutes a refrigeration cycle system having a refrigerant circuit when connected by piping to an indoor unit (not shown). The outdoor unit 200 is filled with refrigerant to be recovered. The outdoor unit 200 has a compressor 230, an outdoor heat exchanger 240, and an accumulator 250. The compressor 230 compresses and discharges the inhaled refrigerant. The outdoor heat exchanger 240 performs heat exchange between the refrigerant and the outdoor air. When the outdoor heat exchanger 240 functions as an evaporator, it evaporates and vaporizes the refrigerant. On the other hand, when it functions as a condenser, it condenses and liquefies the refrigerant, performing supercooling. The accumulator 250 is installed on the refrigerant suction side of the compressor 230. The accumulator 250 is a container that allows gaseous refrigerant to pass through and stores liquid refrigerant. The outdoor unit 200 of Embodiment 1 has, in particular, a high-pressure side connection port 210 and a low-pressure side connection port 220. The high-pressure side connection port 210 is installed in the high-pressure side piping, which is the high-pressure side in the refrigerant circuit, and connects the outside and the inside of the piping via a connected hose. The low-pressure side connection port 220 is installed in the low-pressure side piping, which is the low-pressure side in the refrigerant circuit, and connects the outside and the inside of the piping via a connected hose.

[0015] The recovery unit 300 is a device that has power and other components for recovering refrigerant. The recovery unit 300 has a suction port 310 and a discharge port 320. The suction port 310 is through which fluids such as refrigerant drawn into the recovery unit 300 pass. The discharge port 320 is through which fluids flowing out of the recovery unit 300 pass.

[0016] Furthermore, the cylinder 400 is a recovery container for recovering refrigerant. The cylinder 400 has a liquid inlet 410 and a gas inlet 420. Liquid refrigerant flows in through the liquid inlet 410. Gas, such as gaseous refrigerant, passes through the gas inlet 420. The temperature measuring device 500 is attached, for example, to the underside of the accumulator 250 and measures the temperature T(n) of the accumulator 250 at time n. The temperature measuring device 500 sends a signal including the measured temperature T(n) of the accumulator 250 at time n to the control device 80 of the refrigerant recovery operation automatic switching device 100, which will be described later.

[0017] The refrigerant recovery operation automatic switching device 100 is a device that switches the flow path of a fluid such as a refrigerant between a gas recovery mode for gas recovery and a liquid recovery mode for liquid recovery. The refrigerant recovery operation automatic switching device 100 is connected to various equipment via connecting hoses and has connection ports (connection ports) for fluid communication and a switching unit 70 for switching the flow path. In Embodiment 1, the refrigerant recovery operation automatic switching device 100 has a high-pressure connection port 10, a low-pressure connection port 20, a suction connection port 30, a discharge connection port 40, a liquid connection port 50, and a gas connection port 60 as connection ports. In addition, the refrigerant recovery operation automatic switching device 100 in Embodiment 1 has a first four-way valve 71 and a second four-way valve 72 as the switching unit 70.

[0018] The high-pressure connection port 10 is connected via a connecting hose to a high-pressure side connection port 210 installed on the high-pressure side piping of the outdoor unit 200, and is a port that communicates with the inside of the refrigerant circuit. The low-pressure connection port 20 is connected via a connecting hose to a low-pressure side connection port 220 installed on the low-pressure side piping of the outdoor unit 200, and is a port that communicates with the inside of the refrigerant circuit.

[0019] Furthermore, the suction connection port 30 is a port that is connected to the suction port 310 of the recovery unit 300 via a connecting hose. Also, the discharge connection port 40 is a port that is connected to the discharge port 320 of the recovery unit 300 via a connecting hose.

[0020] Furthermore, the liquid connection port 50 is a port connected to the liquid inlet 410 of the cylinder 400 via a connecting hose. The liquid connection port 50 is primarily through which the liquid refrigerant recovered in the cylinder 400 passes. The gas connection port 60 is a port connected to the gas inlet 420 of the cylinder 400 via a connecting hose. The gas connection port 60 is primarily through which the gaseous refrigerant recovered in the cylinder 400 passes.

[0021] The control device 80 is a device that controls the operation of the refrigerant recovery operation automatic switching device 100. In particular, the control device 80 performs the process of switching the switching unit 70 and performs control related to automatic operation that automatically switches from gas recovery mode to liquid recovery mode. The control device 80 has a determination unit 81, a temperature calculation unit 82, a switching processing unit 83, a timing unit 84, and a storage unit 85. The determination unit 81 performs determination processing in automatic operation, such as mode determination and switching determination. The temperature calculation unit 82 determines the temperature T(n) in the accumulator 250 at time n from the temperature signal sent from the temperature measuring device 500. The temperature calculation unit 82 also performs calculations related to temperature change based on the temperature T(n) data at time n. Furthermore, the switching processing unit 83 performs the process of switching from gas recovery mode to liquid recovery mode based on the determination of the determination unit 81. The timing unit 84 performs timing. The storage unit 85 stores data related to the processing performed by the control device 80.

[0022] Here, the control device 80 has a microcomputer as hardware. The microcomputer has a processing unit such as a CPU (Central Processing Unit). The microcomputer also has I / O ports that manage the input and output of various signals. Furthermore, the microcomputer also has a timer for timing. Therefore, the microcomputer is a device that realizes the functions of the determination unit 81, temperature calculation unit 82, switching processing unit 83, and timing unit 84 described above. However, it is not limited to this, and the control device 80 may be composed of dedicated control equipment (hardware) that realizes the functions of the determination unit 81 and temperature calculation unit 82.

[0023] Furthermore, the control device 80 has, as hardware, a volatile storage device (not shown), such as a random access memory (RAM) that can temporarily store data, and a non-volatile auxiliary storage device (not shown), such as flash memory. These storage devices realize the functions of the storage unit 85 described above. The storage unit 85 has data that is a program of the processing procedures to be performed by the control processing unit of the microcomputer. The processing unit of the microcomputer then executes processing based on the program data. The storage unit 85 also stores data such as setting thresholds that the determination unit 81 uses when making a determination. Setting thresholds and the like are set in advance through experiments or other means.

[0024] Figure 2 is a diagram showing the fluid flow relationship in the gas recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 1. Figure 3 is a diagram showing the fluid flow relationship in the liquid recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 1. The first four-way valve 71 and the second four-way valve 72 are switching valves that switch the communication of connection ports between the liquid recovery mode and the gas recovery mode. As shown in Figure 2, in the gas recovery mode, the first four-way valve 71 works in conjunction with the second four-way valve 72, which will be described later, to connect the low-pressure connection port 20 to the suction connection port 30 and connect the discharge connection port 40 to the liquid connection port 50. Also, as shown in Figure 3, in the liquid recovery mode, the first four-way valve 71 connects the high-pressure connection port 10 to the liquid connection port 50 and connects the low-pressure connection port 20 to the discharge connection port 40. Furthermore, as shown in Figure 2, the second four-way valve 72, in gas recovery mode, works in conjunction with the first four-way valve 71 to connect the high-pressure connection port 10 and the suction connection port 30, and closes the gas connection port 60. Also, as shown in Figure 3, the second four-way valve 72 connects the suction connection port 30 and the gas connection port 60 in liquid recovery mode.

[0025] Based on Figure 2, the fluid flow in the refrigerant recovery operation automatic switching device 100 in gas recovery mode will be explained. In Figure 2, the control device 80, the equipment inside the outdoor unit 200, and the temperature measuring device 500 are not shown in order to make it easier to explain the fluid flow (the same applies to the following diagrams explaining the fluid flow). When the recovery unit 300 is driven, fluid is drawn in through the suction connection port 30. The suction of the recovery unit 300 draws in refrigerant from the connection port of the outdoor unit 200, and it flows out. The refrigerant that flows out from the outdoor unit 200 passes through the high-pressure connection port 10 and the low-pressure connection port 20 in the refrigerant recovery operation automatic switching device 100. Furthermore, the refrigerant passes through the first four-way valve 71 and the second four-way valve 72 and flows out from the suction connection port 30. The refrigerant that flows out from the suction connection port 30 passes through the recovery unit 300 and flows in from the discharge connection port 40. The refrigerant flowing in from the discharge connection port 40 passes through the first four-way valve 71 and flows out from the liquid connection port 50, where it is recovered in the cylinder 400.

[0026] Next, the fluid flow in the refrigerant recovery operation automatic switching device 100 in liquid recovery mode will be explained based on Figure 3. When the recovery unit 300 is driven, fluid is discharged from the recovery unit 300. The discharged fluid passes through the first four-way valve 71 and flows out from the low-pressure connection port 20. The fluid that flows out from the low-pressure connection port 20 passes through the piping and pushes the refrigerant out of the outdoor unit 200. The pushed-out refrigerant flows in from the high-pressure connection port 10, passes through the first four-way valve 71, and flows out from the liquid connection port 50. The refrigerant that flows out from the liquid connection port 50 is recovered in the cylinder 400. Also, when the recovery unit 300 is driven, the fluid that has passed through the gas connection port 60 is sucked in through the suction connection port 30. Also, when the recovery unit 300 is driven, the fluid that has passed through the gas connection port 60 passes through the second four-way valve 72 and is sucked into the recovery unit 300 through the suction connection port 30.

[0027] Figure 4 illustrates the change in the amount of refrigerant recovered over time due to mode switching according to Embodiment 1. In Figure 4, (A) shows the change in the amount of refrigerant recovered over time when the gas recovery mode is continued. (B) shows the change in the amount of refrigerant recovered over time when the accumulator 250 temperature is switched from the gas recovery mode to the liquid recovery mode and recovery is performed when the refrigerant is recovered. In gas recovery, the liquid refrigerant remaining in the accumulator 250 and the like cannot be recovered in its liquid state, and the gaseous refrigerant is recovered as the pressure in the refrigerant circuit decreases and the liquid refrigerant evaporates.

[0028] As shown in Figure 4(A), it can be seen that the recovery speed (weight change) gradually decreases as the gas recovery operation continues. This is because, for example, the temperature of the accumulator 250 decreases due to the latent heat of vaporization caused by the evaporation of the liquid refrigerant, which reduces the density of the recovered gaseous refrigerant, and the liquid refrigerant becomes less likely to evaporate from the oil stored together with the liquid refrigerant in the accumulator 250.

[0029] On the other hand, as shown in Figure 4(B), switching from gas recovery mode to liquid recovery mode restores the pressure in the refrigerant circuit. This suppresses a decrease in the recovery speed. As a result, by changing the refrigerant flow path when the temperature inside the accumulator 250 is low, the recovery time is shortened compared to case (A) where gas recovery was continued.

[0030] Based on the above, in gas recovery mode, the control device 80 switches the switching unit 70 from gas recovery operation to liquid recovery operation based on the temperature of the accumulator 250 inside the outdoor unit 200. Therefore, the refrigerant recovery operation automatic switching device 100 can automatically switch from gas recovery mode to liquid recovery mode without requiring any switching work by an operator.

[0031] Figure 5 is a diagram showing the control flow during automatic recovery operation of the refrigerant recovery operation automatic switching device 100 according to Embodiment 1. Here, the processing related to the automatic recovery operation is performed by each part of the control device 80. Although not particularly limited, the control device 80 performs the processing related to this control at 10-second intervals based on the timing of the timing unit 84. Therefore, the control device 80 determines the weight of the cylinder 400 at 10-second intervals.

[0032] First, the determination unit 81 of the control device 80 determines whether the refrigerant recovery operation automatic switching device 100 is operating in gas recovery mode (step S1). If the determination unit 81 determines that the refrigerant recovery operation automatic switching device 100 is not operating in gas recovery mode, it returns to step S1 and repeats the process.

[0033] On the other hand, if the determination unit 81 determines that the refrigerant recovery operation automatic switching device 100 is operating in gas recovery mode, the temperature calculation unit 82 of the control device 80 obtains the temperature T(n) of the accumulator 250 at time n using the temperature signal from the temperature measuring device 500 (step S2). The temperature calculation unit 82 then calculates the difference ΔT(n) between the temperature T(n) data and a preset temperature threshold Tset (step S3). Here, the temperature threshold Tset is set to, for example, the saturation evaporation temperature of the refrigerant to be recovered.

[0034] The determination unit 81 determines whether ΔT(n)≦0 (step S4). If the determination unit 81 determines that ΔT(n)≦0 is not true, the control device 80 returns to step S1 and repeats the process. On the other hand, if the determination unit 81 determines that ΔT(n)≦0, the switching processing unit 83 of the control device 80 performs a process to switch from gas recovery mode to liquid recovery mode (step S5).

[0035] As described above, with the refrigerant recovery operation automatic switching device 100, the high-pressure connection port 10 and the low-pressure connection port 20 are in communication with the outdoor unit 200. When in gas recovery mode, refrigerant from the outdoor unit 200 can pass through the high-pressure connection port 10 and the low-pressure connection port 20 and be recovered. Therefore, the gas refrigerant recovery speed can be made approximately twice as fast as that of liquid recovery. The refrigerant recovery operation automatic switching device 100 can switch between gas recovery mode and liquid recovery mode by switching at the switching unit 70. Therefore, there is no need to reconnect the connection hoses, and the switching can be done easily, shortening the recovery time. In addition, with the refrigerant recovery operation automatic switching device 100, there is no need to reconnect the connection hoses between gas recovery mode and liquid recovery mode, so the release of refrigerant into the atmosphere when the connection hoses are removed can be reduced. Also, because there is no need to reconnect the connection hoses, connection problems can be reduced, and a reduction in the amount of refrigerant recovered into the cylinder 400 due to insufficient vacuuming can be prevented. Furthermore, in the first embodiment, the automatic refrigerant recovery operation switching device 100 has a switching section 70 consisting of a first four-way valve 71 and a second four-way valve 72. Therefore, the automatic refrigerant recovery operation switching device 100 can be constructed inexpensively by using four-way valves that are readily available on the market.

[0036] Furthermore, according to the refrigerant recovery operation automatic switching device 100 of Embodiment 1, the control device 80 determines the temperature T(n) of the accumulator 250 at time n based on the measurement by the temperature measuring device 500. When the control device 80 determines that the temperature T(n) is lower than a preset temperature threshold Tset, it switches the switching unit 70 from gas recovery mode to liquid recovery mode. As a result, the refrigerant recovery operation automatic switching device 100 can automatically switch from gas recovery mode to liquid recovery mode without requiring any switching work by an operator. Therefore, the workload on operators can be reduced.

[0037] In this embodiment 1, the automatic refrigerant recovery operation switching device 100 determines the switching of the switching unit 70 based on the temperature T(n) of the accumulator 250 at time n, but this is not limited to this. For example, the switching of the switching unit 70 may be determined by the temperature of another liquid reservoir, such as a receiver (not shown) installed in the refrigerant circuit, and refrigerant recovery in the liquid reservoir may be performed.

[0038] Embodiment 2. Figure 6 shows the configuration of a refrigerant recovery system centered on the refrigerant recovery operation automatic switching device 100 according to Embodiment 2. In Figure 6, equipment and other components that have the same reference numerals as in Figure 1 perform the same functions as those described in Embodiment 1. The refrigerant recovery operation automatic switching device 100 in Embodiment 2 has a first four-way valve 71 and a first three-way valve 73 as a switching unit 70.

[0039] Figure 7 shows the fluid flow relationship in the gas recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 2. Figure 8 shows the fluid flow relationship in the liquid recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 2. As shown in Figure 7, the first four-way valve 71 connects the low-pressure connection port 20 to the suction connection port 30 and the discharge connection port 40 to the liquid connection port 50 in the gas recovery mode. As shown in Figure 8, the first four-way valve 71 connects the high-pressure connection port 10 to the liquid connection port 50 and the low-pressure connection port 20 to the discharge connection port 40 in the liquid recovery mode. As shown in Figure 7, the first three-way valve 73 connects the high-pressure connection port 10 to the suction connection port 30 in the gas recovery mode. As shown in Figure 8, the first three-way valve 73 connects the suction connection port 30 to the gas connection port 60 in the liquid recovery mode.

[0040] Based on Figure 7, the fluid flow in the refrigerant recovery operation automatic switching device 100 in gas recovery mode will be explained. When the recovery unit 300 is driven, fluid is drawn in through the suction connection port 30. The suction of the recovery unit 300 draws in refrigerant from the connection port of the outdoor unit 200, and it flows out. The refrigerant that flows out from the outdoor unit 200 passes through the high-pressure connection port 10 and the low-pressure connection port 20 in the refrigerant recovery operation automatic switching device 100. Furthermore, the refrigerant passes through the first four-way valve 71 and the first three-way valve 73 and flows out from the suction connection port 30. The refrigerant that flows out from the suction connection port 30 passes through the recovery unit 300 and flows in from the discharge connection port 40. The refrigerant that flows in from the discharge connection port 40 passes through the first four-way valve 71 and flows out from the liquid connection port 50 and is recovered in the cylinder 400.

[0041] Next, the fluid flow in the refrigerant recovery operation automatic switching device 100 in liquid recovery mode will be explained based on Figure 8. When the recovery unit 300 is driven, fluid is discharged from the recovery unit 300. The discharged fluid passes through the first four-way valve 71 and flows out from the low-pressure connection port 20. The fluid that flows out from the low-pressure connection port 20 passes through the piping and pushes the refrigerant out of the outdoor unit 200. The pushed-out refrigerant flows in from the high-pressure connection port 10, passes through the first four-way valve 71 and flows out from the liquid connection port 50. The refrigerant that flows out from the liquid connection port 50 is recovered in the cylinder 400. Also, when the recovery unit 300 is driven, the fluid that has passed through the gas connection port 60 passes through the first three-way valve 73 and is drawn into the recovery unit 300 via the suction connection port 30.

[0042] As described above, the automatic refrigerant recovery operation switching device 100 in Embodiment 2 uses the first four-way valve 71 and the first three-way valve 73 as the switching unit 70. Therefore, in addition to the effects described in Embodiment 1, the automatic refrigerant recovery operation switching device 100 can be made inexpensive by using four-way valves and three-way valves, which are readily available on the market.

[0043] Embodiment 3. Figure 9 shows the configuration of a refrigerant recovery system centered on the automatic refrigerant recovery operation switching device 100 according to Embodiment 3. In Figure 9, equipment and other components that have the same reference numerals as in Figures 1 and 6 perform the same functions as those described in Embodiments 1 and 2. The automatic refrigerant recovery operation switching device 100 in Embodiment 3 has a switching section 70 comprising a first three-way valve 73, a second three-way valve 74, and a third three-way valve 75.

[0044] Figure 10 shows the fluid flow relationship in the gas recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 3. Figure 11 shows the fluid flow relationship in the liquid recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 3. As shown in Figure 10, the first three-way valve 73 connects the high-pressure connection port 10 and the suction connection port 30 in the gas recovery mode. As shown in Figure 11, the first three-way valve 73 connects the suction connection port 30 and the gas connection port 60 in the liquid recovery mode. Furthermore, as shown in Figure 10, the second three-way valve 74 connects the low-pressure connection port 20 and the suction connection port 30 in the gas recovery mode. Furthermore, as shown in Figure 11, the second three-way valve 74 connects the high-pressure connection port 10 and the liquid connection port 50 in the liquid recovery mode. Furthermore, as shown in Figure 10, the third three-way valve 75 connects the discharge connection port 40 and the liquid connection port 50 in gas recovery mode. Also, as shown in Figure 11, the third three-way valve 75 connects the low-pressure connection port 20 and the discharge connection port 40 in liquid recovery mode.

[0045] Based on Figure 10, the fluid flow in the refrigerant recovery operation automatic switching device 100 in gas recovery mode will be explained. When the recovery unit 300 is driven, fluid is drawn in through the suction connection port 30. The suction of the recovery unit 300 draws in refrigerant from the connection port of the outdoor unit 200, and it flows out. The refrigerant that flows out from the outdoor unit 200 passes through the high-pressure connection port 10 and the low-pressure connection port 20 in the refrigerant recovery operation automatic switching device 100. Furthermore, the refrigerant passes through the first three-way valve 73 and the second three-way valve 74 and flows out from the suction connection port 30. The refrigerant that flows out from the suction connection port 30 passes through the recovery unit 300 and flows in from the discharge connection port 40. The refrigerant that flows in from the discharge connection port 40 passes through the third three-way valve 75 and flows out from the liquid connection port 50 and is recovered in the cylinder 400.

[0046] Next, the fluid flow in the refrigerant recovery operation automatic switching device 100 in liquid recovery mode will be explained based on Figure 11. When the recovery unit 300 is driven, fluid is discharged from the recovery unit 300. The discharged fluid passes through the third three-way valve 75 and flows out from the low-pressure connection port 20. The fluid that flows out from the low-pressure connection port 20 passes through the piping and pushes the refrigerant out of the outdoor unit 200. The pushed-out refrigerant flows in from the high-pressure connection port 10, passes through the second three-way valve 74 and flows out from the liquid connection port 50. The refrigerant that flows out from the liquid connection port 50 is recovered in the cylinder 400. Also, when the recovery unit 300 is driven, the fluid that has passed through the gas connection port 60 passes through the first three-way valve 73 and is drawn into the recovery unit 300 via the suction connection port 30.

[0047] As described above, the automatic refrigerant recovery operation switching device 100 in Embodiment 3 uses the first three-way valve 73, the second three-way valve 74, and the third three-way valve 75 as the switching unit 70. Therefore, in addition to the effects described in Embodiment 1, the automatic refrigerant recovery operation switching device 100 can be made inexpensive by using four-way valves and three-way valves, which are readily available on the market.

[0048] Embodiment 4. Figure 12 is a diagram showing the configuration of a refrigerant recovery system centered on the refrigerant recovery operation automatic switching device 100 according to Embodiment 4. In Figure 12, equipment and other components that have the same reference numerals as in Figures 1 and 6 perform the same functions as those described in Embodiments 1 and 2. The refrigerant recovery operation automatic switching device 100 in Embodiment 4 has a six-way valve 76 and an on-off valve 77 as a switching unit 70.

[0049] Figure 13 is a diagram showing the fluid flow relationship in the gas recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 4. Figure 14 is a diagram showing the fluid flow relationship in the liquid recovery mode of the refrigerant recovery operation automatic switching device 100 according to Embodiment 4. As shown in Figure 13, the six-way valve 76 connects the high-pressure connection port 10 to the suction connection port 30, the low-pressure connection port 20 to the suction connection port 30, and the discharge connection port 40 to the liquid connection port 50. As shown in Figure 14, the six-way valve 76 connects the high-pressure connection port 10 to the liquid connection port 50, the low-pressure connection port 20 to the discharge connection port 40, and the suction connection port 30 to the gas connection port 60. The on-off valve 77 is closed in the gas recovery mode to prevent fluid from passing through the gas connection port 60. The on-off valve 77 is open in the liquid recovery mode.

[0050] Based on Figure 13, the fluid flow in the refrigerant recovery operation automatic switching device 100 in gas recovery mode will be explained. When the recovery unit 300 is driven, fluid is drawn in through the suction connection port 30. The suction of the recovery unit 300 draws in refrigerant from the connection port of the outdoor unit 200, and it flows out. The refrigerant that flows out from the outdoor unit 200 passes through the high-pressure connection port 10 and the low-pressure connection port 20 in the refrigerant recovery operation automatic switching device 100. Furthermore, the refrigerant passes through the six-way valve 76 and flows out from the suction connection port 30. The refrigerant that flows out from the suction connection port 30 passes through the recovery unit 300 and flows in from the discharge connection port 40. The refrigerant that flows in from the discharge connection port 40 passes through the six-way valve 76 and flows out from the liquid connection port 50 and is recovered in the cylinder 400. At this time, since the on-off valve 77 is closed, no fluid passes through the gas connection port 60.

[0051] Next, the fluid flow in the refrigerant recovery operation automatic switching device 100 in liquid recovery mode will be explained based on Figure 14. When the recovery unit 300 is driven, fluid is discharged from the recovery unit 300. The discharged fluid passes through the six-way valve 76 and flows out from the low-pressure connection port 20. The fluid that flows out from the low-pressure connection port 20 passes through the piping and pushes the refrigerant out of the outdoor unit 200. The pushed-out refrigerant flows in from the high-pressure connection port 10, passes through the six-way valve 76, and flows out from the liquid connection port 50. The refrigerant that flows out from the liquid connection port 50 is recovered in the cylinder 400. Also, when the recovery unit 300 is driven, the fluid that has passed through the gas connection port 60 passes through the on-off valve 77 and the six-way valve 76 and is sucked into the recovery unit 300 via the suction connection port 30.

[0052] As described above, in Embodiment 4, the automatic refrigerant recovery operation switching device 100 uses a six-way valve 76 and an on-off valve 77 as the switching unit 70. Therefore, in addition to the effects described in Embodiment 1, the automatic refrigerant recovery operation switching device 100 can reduce the number of components involved in the switching process.

[0053] Embodiment 5. Figure 15 is a diagram showing the configuration of a refrigerant recovery system centered on a refrigerant recovery device 110 according to Embodiment 5. In Figure 15, equipment and other components that have the same reference numerals as in Figure 1 perform the same functions as those described in Embodiment 1. The refrigerant recovery device 110 in Embodiment 5 is composed of the equipment of the refrigerant recovery operation automatic switching device 100 and the recovery unit 300 described in Embodiment 1 and other embodiments. Here, since the refrigerant recovery operation automatic switching device 100 described in Embodiment 1 and other embodiments is located inside the refrigerant recovery device 110, the suction connection port 30 and discharge connection port 40, which function as connections to external equipment, are not shown in Figure 15. However, there are connection ports through which fluid passes when connected to equipment related to recovery.

[0054] The refrigerant recovery device 110 in Embodiment 5 includes a recovery compressor 330, a recovery three-way valve 340, and a condenser 350. The recovery compressor 330 discharges the sucked gaseous refrigerant. The recovery three-way valve 340 is a valve that switches between allowing the refrigerant to pass through the condenser 350 when performing gas recovery and bypassing the condenser 350 when performing liquid recovery. The condenser 350 is a heat exchanger that condenses and liquefies the gaseous refrigerant when performing gas recovery, and discharges the liquid refrigerant from the liquid connection port 50.

[0055] Figure 16 is a diagram showing the fluid flow relationship in the gas recovery mode of the refrigerant recovery device 110 according to Embodiment 5. Based on Figure 16, the fluid flow in the gas recovery mode will be explained. When the recovery compressor 330 is driven, refrigerant is sucked in from the connection port of the outdoor unit 200 and flows out. The refrigerant that flows out from the outdoor unit 200 passes through the high-pressure connection port 10 and the low-pressure connection port 20 in the refrigerant recovery device 110. The refrigerant then passes through the first four-way valve 71 and the second four-way valve 72, and further flows into the condenser 350 via the recovery compressor 330 and the recovery unit three-way valve 340. The refrigerant that flows into the condenser 350 condenses and liquefies, flows out from the liquid connection port 50, and is recovered in the cylinder 400. At this time, no fluid passes through the gas connection port 60.

[0056] Figure 17 is a diagram showing the fluid flow relationship in the liquid recovery mode of the refrigerant recovery device 110 according to Embodiment 5. Based on Figure 17, the fluid flow in the liquid recovery mode will be explained. When the recovery compressor 330 is driven, the fluid that has passed through the gas connection port 60, which is connected to the gas inlet 420 of the cylinder 400 via a connecting hose, passes through the second four-way valve 72 and is sucked into the recovery compressor 330 via the suction connection port 30. The fluid discharged from the recovery compressor 330 then passes through the recovery unit three-way valve 340 and the first four-way valve 71 and flows out from the low-pressure connection port 20. The fluid that flows out from the low-pressure connection port 20 passes through the piping and pushes the refrigerant out of the outdoor unit 200. The pushed-out refrigerant flows in from the high-pressure connection port 10, passes through the first four-way valve 71 and flows out from the liquid connection port 50. The refrigerant that flows out from the liquid connection port 50 is recovered in the cylinder 400.

[0057] As described above, the refrigerant recovery device 110 in Embodiment 5 has a recovery compressor 330 and a condenser 350 that function as a recovery unit 300, and recovers gaseous refrigerant as liquid refrigerant into a cylinder 400. Therefore, connection ports and the like are not required, and the amount of equipment necessary for refrigerant recovery can be reduced. [Explanation of Symbols]

[0058] 10 High-pressure connection port, 20 Low-pressure connection port, 30 Suction connection port, 40 Discharge connection port, 50 Liquid connection port, 60 Gas connection port, 70 Switching unit, 71 First four-way valve, 72 Second four-way valve, 73 First three-way valve, 74 Second three-way valve, 75 Third three-way valve, 76 Six-way valve, 77 On / off valve, 80 Control device, 81 Judgment unit, 82 Temperature calculation unit, 83 Switching processing unit, 84 Timing unit, 85 Memory unit, 100 Refrigerant recovery operation automatic switching device, 200 Outdoor unit, 210 High-pressure side connection port, 220 Low-pressure side connection port, 230 Compressor, 240 Outdoor heat exchanger, 250 Accumulator, 300 Recovery unit, 310 Suction port, 320 Discharge port, 330 Recovery compressor, 340 Recovery unit three-way valve, 350 condenser, 400 cylinder, 410 liquid port, 420 gas port, 500 temperature measuring device.

Claims

1. An automatic refrigerant recovery operation switching device that switches the flow path of the refrigerant when the refrigerant in the refrigeration cycle device is recovered into a cylinder by driving a recovery machine, A high-pressure connection port that communicates with the high-pressure side connection port of the high-pressure side piping of the refrigeration cycle device, A low-pressure connection port that communicates with the low-pressure side connection port of the low-pressure side piping of the refrigeration cycle device, A suction connection port connected to the suction port of the recovery machine, A discharge connection port connected to the discharge port of the recovery machine, A liquid connection port that connects to the liquid inlet of the cylinder, A gas connection port that connects to the gas inlet of the aforementioned cylinder, In a liquid recovery mode for recovering liquid refrigerant in the refrigeration cycle device, a switching unit switches between a flow path that connects the gas connection port and the suction connection port, the discharge connection port and the low-pressure connection port, and the high-pressure connection port and the liquid connection port; and in a gas recovery mode for recovering gaseous refrigerant in the refrigeration cycle device, a switching unit switches between a flow path that connects the high-pressure connection port and the low-pressure connection port and the suction connection port, and the discharge connection port and the liquid connection port. The switching unit includes a control device that switches the flow path, The control device is A determination unit determines that the temperature in the liquid reservoir of the refrigeration cycle device is lower than the set temperature, and determines whether to switch from the gas recovery mode to the liquid recovery mode. An automatic refrigerant recovery operation switching device having a switching processing unit that performs switching processing of the flow path in the switching unit when the determination unit determines that a switch is being made.

2. The refrigerant recovery operation automatic switching device according to claim 1, wherein the switching unit has two four-way valves.

3. The refrigerant recovery operation automatic switching device according to claim 1, wherein the switching unit comprises one four-way valve and one three-way valve.

4. The refrigerant recovery operation automatic switching device according to claim 1, wherein the switching unit has three three-way valves.

5. The refrigerant recovery operation automatic switching device according to claim 1, wherein the switching unit has one six-way valve.

6. A refrigerant recovery apparatus comprising a refrigerant recovery operation automatic switching device and a recovery machine according to any one of claims 1 to 5.

7. The refrigerant recovery device according to claim 6, wherein the recovery device comprises a compressor for compressing the refrigerant and a condenser for condensing the refrigerant.

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