Gas cylinder pressure adjustment device and refrigerant recovery device

Abstract

A pressure adjustment device (4) comprises: a first connection port (P1) that is configured so as to be connected to a gauge manifold (5) for recovering a refrigerant from a refrigerant recovery target device; a second connection port (P2) that is configured so as to be in communication with the first connection port (P1) and so as to be connected to a suction port of a compressor (21) that compresses the refrigerant to be recovered; a third connection port (P3) that is configured so as to be connected to a gas port (32) of a refrigerant recovery gas cylinder (3); and a pressure adjustment device (41) that is connected between the first connection port (P1) or the second connection port (P2), and the third connection port (P3).

Description

Cylinder pressure regulator and refrigerant recovery device

[0001] The present invention relates to a cylinder pressure regulating device and a refrigerant recovery device.

[0002] As a prior art technique, Japanese Patent Application Laid-Open Publication No. 2020-180746 (Patent Document 1) discloses a refrigerant recovery system that aims to improve refrigerant recovery efficiency. This refrigerant recovery system is configured to charge a refrigerant recovery cylinder with refrigerant from an air conditioner via a recovery device. The cooling device includes a tank that stores water, a water supply pump that pressurizes the water in the tank, a spray nozzle that sprays the pressurized water, and a blower fan. The blower fan blows air containing water sprayed by the spray nozzle toward the refrigerant recovery cylinder. The water-containing air sent cools the refrigerant recovery cylinder.

[0003] Japanese Patent Application Laid-Open No. 2020-180746

[0004] Generally, when recovering refrigerant at high ambient temperatures, the performance of the heat exchanger in the refrigerant recovery device may be insufficient, causing two-phase refrigerant to flow into the refrigerant recovery cylinder. This increases the gas density in the refrigerant recovery cylinder, causing the pressure to rise. If the pressure exceeds a specified value (e.g., 3 MPa), the refrigerant recovery device shuts down to ensure the safety of the refrigerant recovery cylinder. To resume recovery, the system must wait until the cylinder temperature and pressure drop, resulting in a longer recovery time. The refrigerant recovery system disclosed in JP 2020-180746 A (Patent Document 1) reduces the cylinder pressure by spraying water from a spray nozzle.

[0005] However, in the cylinder pressure regulating device described in Patent Document 1, a cooling device is introduced to cool the refrigerant recovery cylinder to avoid high pressure cuts, but using a cooling device increases the burden on the worker, which creates a work burden.

[0006] The present disclosure is intended to solve such problems, and its purpose is to provide a cylinder pressure regulating device and a refrigerant recovery device that can reduce the burden on workers while avoiding the refrigerant recovery device shutting down due to pressure increases.

[0007] One aspect of the present disclosure relates to a cylinder pressure adjustment device for adjusting the pressure in a refrigerant recovery cylinder when a refrigerant from a refrigerant recovery device is compressed by a compressor and recovered in the refrigerant recovery cylinder. The cylinder pressure adjustment device includes a first connection port configured to be connected to a service valve of the refrigerant recovery device, a second connection port communicating with the first connection port and configured to be connected to a suction port of the compressor, a third connection port configured to be connected to a gas port of the refrigerant recovery cylinder, and a pressure adjustment device connected between the first connection port and the third connection port.

[0008] Another aspect of the present disclosure relates to a refrigerant recovery device including a cylinder pressure regulating device.

[0009] According to the present disclosure, the pressure in the cylinder can be adjusted, thereby avoiding the recovery device from being stopped due to high pressure and reducing the effort required for workers to carry luggage.

[0010] FIG. 1 is a diagram showing the connection relationship of a cylinder pressure regulating device. FIG. 2 is a diagram showing the configuration of a refrigeration cycle device and a recovery device to which a cylinder pressure regulating device is connected in embodiment 1. FIG. 3 is a model diagram of a refrigerant recovery device. FIG. 4 is a diagram showing the relationship between condensation temperature, refrigerant flow rate, and dryness fraction. FIG. 5 is a diagram showing the relationship between refrigerant flow rate and dryness fraction. FIG. 6 is a diagram showing the configuration of a refrigeration cycle device and a recovery device to which a cylinder pressure regulating device is connected in embodiment 2. FIG. 7 is a diagram showing the configuration of a refrigeration cycle device and a recovery device to which a cylinder pressure regulating device is connected in embodiment 3. FIG. 8 is a diagram showing the connection relationship of a refrigerant recovery device in embodiment 4. FIG. 9 is a diagram showing the configuration of a refrigerant recovery device incorporating a cylinder pressure regulating device and a refrigeration cycle device connected thereto in embodiment 4. FIG. 10 is a diagram showing the configuration of a refrigerant recovery device incorporating a cylinder pressure regulating device and a refrigeration cycle device connected thereto in embodiment 5. FIG. 11 is a diagram showing the configuration of a refrigerant recovery device incorporating a cylinder pressure regulating device and a refrigeration cycle device connected thereto in embodiment 6. FIG. 12 is a flowchart for explaining control performed by control device 25C in embodiment 6. FIG. 13 is a diagram showing the configuration of a refrigerant recovery device incorporating a cylinder pressure regulating device and a refrigeration cycle device connected thereto in embodiment 7. 13 is a flowchart for illustrating control performed by a control device 25D in the seventh embodiment.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Below, embodiments including multiple modifications will be described, but it was originally intended that the configurations described in each embodiment be combined as appropriate. Note that identical or corresponding parts in the drawings will be designated by the same reference numerals, and their description will not be repeated.

[0012] 1 is a diagram showing the connections of a cylinder pressure regulating device 4. The cylinder pressure regulating device 4 is connected to a refrigeration cycle device 1, a refrigerant recovery device 2, and a refrigerant recovery cylinder 3.

[0013] When a refrigeration cycle device is disposed of or relocated, it is necessary to recover the refrigerant. An operator starts the refrigerant recovery device 2 and sends the refrigerant to the refrigerant recovery cylinder 3. The refrigerant recovery device 2 has a built-in condensation heat exchanger. The cylinder pressure adjustment device 4 includes a pressure adjustment device 41.

[0014] In embodiment 1, the operator uses the pressure regulating device 41 to adjust the pressure of the refrigerant recovery cylinder 3 to near the high-pressure cut value determined by the cylinder's pressure resistance, etc., so that the heat exchange amount of the condensation heat exchanger is maximized.

[0015] FIG. 2 is a diagram showing the configuration of a refrigeration cycle device and a recovery device to which a cylinder pressure adjusting device is connected in the first embodiment.

[0016] The target device for refrigerant recovery is, for example, a refrigeration cycle device 1 such as an air conditioner. The refrigeration cycle device 1 includes an outdoor unit, an indoor unit, and extension pipes 14 and 17 connecting these units.

[0017] The refrigeration cycle device includes a compressor 11, an outdoor heat exchanger 12, an expansion valve 15, an indoor heat exchanger 16, and service valves 13 and 18. The service valve is also called a valve with a service port, and is provided with a service port for charging refrigerant into the refrigerant circuit.

[0018] 2, the expansion valve 15 and the indoor heat exchanger 16 are arranged in the indoor unit, while the compressor 11, the outdoor heat exchanger 12, and the service valves 13 and 18 are arranged in the outdoor unit.

[0019] The refrigeration cycle apparatus 1 includes a refrigerant circuit C1. In the refrigerant circuit C1, the refrigerant discharged from the discharge port of the compressor 11 flows through the outdoor heat exchanger 12, the service valve 13, the extension pipe 14, the expansion valve 15, the indoor heat exchanger 16, the extension pipe 17, and the service valve 18 in this order, before returning to the suction port of the compressor 11.

[0020] When recovering refrigerant, an operator connects the gauge manifold 5 to the refrigeration cycle apparatus 1. The gauge manifold 5 has three connection ports 5A-5C. The connection port 5A is connected to the service valve 13 by a charge hose 51. The connection port 5B is connected to the service valve 18 by a charge hose 52.

[0021] The cylinder pressure adjusting device 4 includes a first connection port P1, a second connection port P2, a third connection port P3, and a pressure adjusting device 41.

[0022] The first connection port P1 is configured to be connected by a charge hose 53 to a connection port 5C of a gauge manifold 5 for recovering refrigerant from the refrigeration cycle apparatus 1, which is the apparatus to be recovered. The first connection port P1 may be the end of the charge hose 53 connected to the connection port 5C. However, the charge hose 53 may be connected directly to the service valve 13 or the service valve 18 without going through the gauge manifold 5. In other words, the first connection port P1 is connected to the service valve of the apparatus to be recovered refrigerant directly or via the gauge manifold 5.

[0023] The second connection port P2 communicates with the first connection port P1 and is configured to be connected to the suction port of the compressor 21 that compresses the refrigerant to be recovered by a charge hose 54. The second connection port P2 may be an end of the charge hose 54 that is connected to the suction port of the compressor 21.

[0024] The third connection port P3 is configured to be connected to the gas port 32 of the refrigerant recovery cylinder 3 by a charge hose 56. The third connection port P3 may be the end of the charge hose 56 that is connected to the gas port 32.

[0025] The pressure adjusting device 41 is connected between the third connection port P3 and the first and second connection ports P1 and P2.

[0026] In this embodiment, as shown by the broken line in FIG. 2, the gauge manifold 5 is set so that the connection port 5C communicates with both the connection ports 5A and 5B internally.

[0027] The refrigerant recovery device 2 includes a compressor 21, a heat exchanger 22, a fan 23, a pressure sensor 24, and a control device 25. The compressor 21 is configured to compress the refrigerant sent from the gauge manifold 5. The heat exchanger 22 exchanges heat between the compressed refrigerant and air and sends the refrigerant toward the liquid port 31 of the refrigerant recovery cylinder 3.

[0028] In the configuration shown in Figure 2, the refrigerant recovery device 2 and the cylinder pressure adjustment device 4 are independent. A general refrigerant recovery device may be used as the refrigerant recovery device 2. The cylinder pressure adjustment device 4 uses a pressure control valve as the pressure adjustment device 41.

[0029] When the pressure is higher than the target value, the operator opens the pressure control valve to prevent the cylinder pressure from exceeding the upper limit judgment value and to prevent the refrigerant recovery device 2 from automatically shutting down. On the other hand, when the cylinder pressure is lower than the target value below the upper limit judgment value, the operator throttles the pressure control valve to increase the cylinder pressure, thereby increasing the heat exchange amount in the heat exchanger 22.

[0030] In the cylinder pressure regulating device 4 of the first embodiment, since there is no controller in the flow path portion that bypasses the gas, no power source is required and the speed of refrigerant recovery can be improved at low cost.

[0031] The relationship between pressure adjustment and refrigerant recovery speed will now be explained. Figure 3 is a model diagram of a refrigerant recovery system. Refrigerant passing through the refrigerant recovery system at a flow rate Gr flows into heat exchanger 22 with a specific enthalpy hi, exchanges heat with air, and flows out of heat exchanger 22 with a specific enthalpy -ho, before being sent to a cylinder.

[0032] FIG. 4 shows the relationship between condensing temperature, refrigerant flow rate, and quality fraction. The conditions for the graph in FIG. 4 are: refrigerant R410A, condensing temperature Tc = 50°C, compressor discharge temperature T = 80°C, refrigerant flow rate Gr = 10 kg / h, and heat exchange potential 30 W / k. Here, heat exchange potential is a value indicating the heat exchange amount per 1 K of temperature difference between air and refrigerant. The heat exchanger 22 of the refrigerant recovery system is designed to liquefy the inflowing gas refrigerant. When the outside air temperature is high, the heat exchange amount is insufficient, and the refrigerant at the outlet of the heat exchanger 22 becomes a two-phase state. In this case, the specific enthalpy ho of the refrigerant at the outlet of the heat exchanger 22 decreases as the condensing temperature Tc increases. A decrease in specific enthalpy ho is equivalent to a decrease in the quality fraction Xo of the refrigerant at the outlet.

[0033] As shown in the graph of FIG. 4, as the condensation temperature Tc increases, the quality fraction Xo decreases and the liquid refrigerant flow rate GrL (liquid inflow rate into the cylinder) increases.

[0034] FIG. 5 shows the relationship between refrigerant flow rate and quality fraction. The conditions for the graph in FIG. 5 are: refrigerant R410A, condensing temperature Tc = 50°C, outside air temperature 35°C, compressor discharge temperature T = 80°C, refrigerant flow rate Gr = 10 kg / h, and heat exchange potential 30 W / k. Here, heat exchange potential is a value indicating the amount of heat exchanged per 1 K of temperature difference between the air and the refrigerant. The liquid refrigerant flow rate GrL is the rate at which the liquid refrigerant is recovered in the cylinder. As shown in FIG. 5, as the refrigerant flow rate Gr decreases, the quality fraction Xo decreases. In other words, as the refrigerant flow rate Gr decreases, (1 - Xo) increases. The liquid refrigerant flow rate GrL is expressed by the following equation: GrL = Gr × (1 - Xo) When the refrigerant flow rate Gr decreases, (1 - Xo) increases in the above equation, so the direction of increase or decrease of the liquid refrigerant flow rate GrL, which indicates the liquid recovery speed, is not simply known. However, simulation results show that the liquid refrigerant flow rate GrL and the quality fraction Xo change depending on the refrigerant flow rate Gr, as shown in the graph in Figure 5. In the two-phase region where the quality fraction Xo is 0 < Xo < 1, the liquid refrigerant flow rate GrL increases as the refrigerant flow rate Gr decreases. In other words, the liquid recovery speed from the cylinder increases as the refrigerant flow rate Gr decreases. This is because the impact of the decrease in the quality fraction Xo when the refrigerant flow rate Gr decreases is greater than the impact of the decrease in the refrigerant flow rate Gr.

[0035] Therefore, in the example shown in Fig. 5, the refrigerant recovery rate is maximized by setting the refrigerant flow rate Gr to approximately 10 kg / h. Therefore, the liquid recovery rate is maximized under the condition of refrigerant flow rate Gr = 10 kg / h obtained in Fig. 4, and the refrigerant recovery rate increases as the condensation temperature Tc increases, as shown in Fig. 4.

[0036] As described above, by using the cylinder pressure regulating device of embodiment 1, the refrigerant recovery device can be prevented from shutting down due to pressure increases when the outside temperature is high by using a gas bypass, eliminating the waiting time during high-pressure shutdown and shortening the refrigerant recovery time. Furthermore, the pressure regulating device can maximize the amount of heat exchange, promoting liquefaction and shortening the recovery time.

[0037] In other words, in embodiment 1, the pressure is adjusted using the cylinder pressure adjustment device 4, and the refrigerant recovery device 2 can be continuously operated so that the condensation temperature Tc is as high as possible and does not exceed the pressure protection judgment value, so the refrigerant recovery speed can be made faster than conventional methods without the need for an additional device to cool the cylinder.

[0038] Embodiment 2 In the first embodiment, a pressure control valve whose opening is controlled by an operator is provided as the pressure adjusting device 41. In contrast, in the second embodiment, instead of the pressure control valve, a pressure adjusting valve is used which automatically opens when the pressure exceeds a predetermined threshold value and automatically closes when the pressure is equal to or lower than the threshold value.

[0039] Fig. 6 is a diagram showing the configuration of a refrigeration cycle apparatus and a recovery apparatus connected to a cylinder pressure adjusting device in embodiment 2. In Fig. 6, the configurations of the refrigeration cycle apparatus 1, the refrigerant recovery apparatus 2, and the refrigerant recovery cylinder 3 are the same as those in Fig. 2, and therefore description thereof will not be repeated here.

[0040] The cylinder pressure regulating device 4A shown in Fig. 6 includes a pressure regulating device 41A instead of the pressure regulating device 41 in the configuration of the cylinder pressure regulating device 4 shown in Fig. 2. The cylinder pressure regulating device 4A uses a pressure regulating valve as the pressure regulating device 41A.

[0041] If a pressure regulating valve is used as the pressure regulating device 41A, the pressure control valve will automatically open when the pressure is higher than the target value, preventing high-pressure cutoff. Also, when the pressure is lower than the target value, the pressure regulating valve will automatically throttle, increasing the pressure and increasing the heat exchange amount.

[0042] Even with this configuration, the cylinder pressure adjusting device 4A does not require a controller and therefore does not require a power source. In addition, unlike the first embodiment, there is no need for an operator to adjust the pressure.

[0043] Embodiment 3. In embodiment 2, a pressure regulating valve was used that automatically opens when the pressure exceeds a predetermined threshold and automatically closes when the pressure is equal to or lower than the threshold. In embodiment 3, an electronic expansion valve is used as the pressure regulating device.

[0044] Fig. 7 is a diagram showing the configuration of a refrigeration cycle apparatus and a recovery apparatus connected to a cylinder pressure adjusting device in embodiment 3. In Fig. 7, the configurations of the refrigeration cycle apparatus 1, the refrigerant recovery device 2, and the refrigerant recovery cylinder 3 are the same as those in Figs. 2 and 6, and therefore description thereof will not be repeated here.

[0045] The cylinder pressure regulating device 4B shown in Fig. 7 has the same configuration as the cylinder pressure regulating device 4A shown in Fig. 6, but includes a pressure regulating device 41B instead of the pressure regulating device 41A, a pressure sensor 42, and a control device 43. The cylinder pressure regulating device 4B uses an electronic expansion valve, the opening of which is controlled by the control device 43, as the pressure regulating device 41B.

[0046] The control device 43 includes a CPU and a memory. The control device 43 is configured to adjust the opening degree of the pressure adjusting device 41B in accordance with the output of the pressure sensor 42. The CPU is a computing unit that controls the expansion valve by executing various programs. The CPU has the function of performing various processes by executing the programs, but some or all of these functions may be implemented using dedicated hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0047] The memory provides a storage area for storing program code, various variables, etc. when the CPU executes various programs. Examples of memory include volatile memory such as DRAM (dynamic random access memory) and SRAM (static random access memory), and non-volatile memory such as ROM (read only memory) and flash memory.

[0048] 7, if the cylinder pressure regulating device 4B is configured to include a control device 43, an electronic expansion valve (41B), and a pressure sensor 42, when the pressure is higher than the target value, the control device 43 opens the electronic expansion valve, thereby preventing the refrigerant recovery device from shutting down due to high pressure. Also, when the pressure is lower than the target value, the control device 43 throttles the electronic expansion valve, thereby increasing the pressure and increasing the heat exchange amount.

[0049] The pressure resistance of the refrigerant recovery cylinder may differ depending on the type of refrigerant. Therefore, when an operator inputs the type of refrigerant recovery cylinder or the type of refrigerant into the control device 43, the control specification is set so that the target pressure is automatically changed to a pressure corresponding to the cylinder type, making it possible to respond to changes in refrigerant.

[0050] Embodiment 4. In the first to third embodiments, a cylinder pressure regulating device is described which is connected to a general refrigerant recovery device. In the fourth embodiment, a refrigerant recovery device having a built-in cylinder pressure regulating device will be described.

[0051] 8 is a diagram showing the connections of a refrigerant recovery apparatus according to embodiment 4. The refrigerant recovery apparatus 2A is connected to the refrigeration cycle apparatus 1 and the refrigerant recovery cylinder 3. The refrigerant recovery apparatus 2A includes a compressor 21, a heat exchanger 22, and a pressure adjusting device 41.

[0052] The refrigerant recovery device 2A further includes a housing 60 that houses a pressure adjusting device 41, which is a main part of the cylinder pressure adjusting device, a compressor 21, and a heat exchanger 22.

[0053] 9 is a diagram showing the configuration of a refrigerant recovery device incorporating a cylinder pressure adjusting device and a refrigeration cycle device connected thereto in embodiment 4. In Fig. 9, the configurations of refrigeration cycle device 1 and refrigerant recovery cylinder 3 are the same as those in Fig. 2 etc., and therefore description thereof will not be repeated here.

[0054] The refrigerant recovery device 2A shown in Fig. 9 has a configuration in which the cylinder pressure adjustment device 4 shown in Fig. 2 is built into the refrigerant recovery device 2. That is, the refrigerant recovery device 2A includes a pressure adjustment device 41 and a control device 25 in addition to a compressor 21, a heat exchanger 22, a fan 23, and a pressure sensor 24. These components of the refrigerant recovery device 2A are housed in a single housing.

[0055] With this configuration, when the pressure is higher than the target value, the operator can open the pressure control valve to prevent the compressor from stopping due to high pressure.When the pressure is lower than the target value, the operator can increase the pressure by throttling the pressure control valve, thereby increasing the heat exchange amount and the refrigerant recovery speed.

[0056] When recovering the refrigerant, the operator starts the refrigerant recovery device and recovers the refrigerant into the recovery cylinder. At this time, since the refrigerant recovery device has a built-in pressure control valve, the operator can adjust the pressure using the pressure adjustment device so that the heat exchange amount of the condensing heat exchanger 22 is maximized (i.e., the pressure is close to the high-pressure judgment value).

[0057] This allows the gas bypass to avoid the refrigerant recovery device's high-pressure protection shutdown when the outside temperature is high, thereby shortening the recovery time. The pressure regulator also maximizes the heat exchange rate, promoting liquefaction and further shortening the recovery time. Furthermore, by incorporating the cylinder pressure regulator of the first embodiment into the refrigerant recovery device, the amount of equipment that workers need to carry can be reduced.

[0058] Embodiment 5. Figure 10 is a diagram showing the configuration of a refrigerant recovery device incorporating a cylinder pressure adjusting device and a refrigeration cycle device connected thereto in embodiment 5. In Figure 10, the configurations of the refrigeration cycle device 1 and the refrigerant recovery cylinder 3 are the same as those in Figure 2 etc., so description thereof will not be repeated here.

[0059] The refrigerant recovery device 2B shown in Figure 10 has a configuration in which the cylinder pressure adjustment device 4A shown in Figure 6 is built into the refrigerant recovery device 2. That is, the refrigerant recovery device 2B includes a pressure adjustment device 41A and a control device 25 in addition to a compressor 21, a heat exchanger 22, a fan 23, and a pressure sensor 24. These components of the refrigerant recovery device 2B are housed in a single housing. A pressure adjustment valve can be used as the pressure adjustment device 41A.

[0060] With this configuration, when the pressure is higher than the target value, the pressure regulating valve automatically opens without operator intervention, preventing the compressor from stopping due to high pressure. When the pressure is lower than the target value, the pressure regulating valve automatically narrows its opening without operator intervention, increasing the pressure, thereby increasing the heat exchange amount and refrigerant recovery speed.

[0061] Embodiment 6. Figure 11 is a diagram showing the configuration of a refrigerant recovery device incorporating a cylinder pressure adjusting device and a refrigeration cycle device connected thereto in embodiment 6. In Figure 11, the configurations of the refrigeration cycle device 1 and the refrigerant recovery cylinder 3 are the same as those in Figure 2 etc., so description thereof will not be repeated here.

[0062] The refrigerant recovery device 2C shown in Figure 11 is configured by integrating the cylinder pressure adjustment device 4B shown in Figure 7 with a control device and incorporating it into the refrigerant recovery device 2. That is, the refrigerant recovery device 2C includes a temperature sensor 26, a pressure adjustment device 41C, and a control device 25C in addition to the compressor 21, heat exchanger 22, fan 23, and pressure sensor 24. These components of the refrigerant recovery device 2C are housed in the same housing. An electronic expansion valve can be used as the pressure adjustment device 41C.

[0063] The control device 25C can control both the compressor 21 and the pressure adjusting device 41C based on the outputs of the pressure sensor 24 and the temperature sensor 26.

[0064] In the sixth embodiment, the pressure adjusting device 41C is an expansion valve connected between the third connection port P3 and the first connection port P1. The control device 25C adjusts the pressure with the expansion valve and is configured to control the operating frequency of the compressor 21 so as to increase the flow rate of liquid refrigerant from the heat exchanger 22 to the liquid port 31.

[0065] When an operator inputs the type of cylinder (pressure resistance of the cylinder) into the control device 25C of the refrigerant recovery device 2C, the target pressure is automatically changed, making it possible to accommodate changes in refrigerant. Since the electronic expansion valve (41C) can be controlled by the control device that controls the compressor originally installed in the recovery device, only one control device is required.

[0066] FIG. 12 is a flowchart illustrating the control performed by the control device 25C in the sixth embodiment. Before starting the refrigerant recovery device 2C, the operator sets the type of refrigerant recovery cylinder or the type of refrigerant in the control device 25C. The control device 25C then automatically sets a target value corresponding to the refrigerant. When the operator starts the refrigerant recovery device 2C, in step S1, the control device 25C starts the compressor 21 and the fan 23 of the heat exchanger 22. Then, in step S2, the control device 25C determines whether the pressure detected by the pressure sensor 24 is higher than the target value.

[0067] When the pressure is higher than the target value (YES in S2), the control device 25C increases the opening of the electronic expansion valve to avoid a protective shutdown of the compressor 21 due to high pressure (S3). On the other hand, when the pressure is lower than the target value (NO in S2), the control device 25C decreases the opening of the electronic expansion valve (S4), increasing the pressure and thereby increasing the heat exchange amount.

[0068] In step S5, the control device 25C obtains the outlet temperature of the heat exchanger 22 from the temperature sensor 26 and determines whether the temperature is higher than the saturation temperature of the refrigerant. The saturation temperature can be obtained by using a map or calculation based on the pressure measured by the pressure sensor 24.

[0069] When the temperature is higher than the saturation temperature (YES in S5), the control device 25C reduces the operating frequency of the compressor 21 (S6). This reduces the dryness fraction at the outlet of the heat exchanger 22. On the other hand, when the temperature is equal to or lower than the saturation temperature (NO in S5), the control device 25C increases the operating frequency of the compressor 21 (S7). This increases the flow rate of the liquid refrigerant.

[0070] In step S8, the control device 25C determines whether the switch of the refrigerant recovery device has been turned off by an operator. If the switch has not been turned off (NO in S8), the control device 25C executes the processes from step S2 onward again. If the switch has been turned off (YES in S8), the control device 25C stops the compressor 21 and the fan 23 of the heat exchanger 22.

[0071] By controlling in this manner, the electronic expansion valve is throttled to increase the pressure, and the operating frequency of the compressor is reduced to lower the dryness of the refrigerant at the outlet of the heat exchanger, thereby increasing the refrigerant recovery speed.

[0072] Embodiment 7 Fig. 13 is a diagram showing the configuration of a refrigerant recovery device incorporating a cylinder pressure adjusting device and a refrigeration cycle device connected thereto in embodiment 7. In Fig. 13, the configurations of the refrigeration cycle device 1 and the refrigerant recovery cylinder 3 are the same as those in Fig. 2 etc., and therefore description thereof will not be repeated here.

[0073] The refrigerant recovery device 2D shown in Figure 13 is configured by integrating the cylinder pressure regulating device 4B shown in Figure 7 with a control device and incorporating it into the refrigerant recovery device 2, and further adding an expansion valve 27 disposed at the refrigerant suction port of the compressor 21. That is, the refrigerant recovery device 2D includes not only the compressor 21, heat exchanger 22, fan 23, and pressure sensor 24, but also a temperature sensor 26, a pressure regulating device 41C, an expansion valve 27, and a control device 25D. These components of the refrigerant recovery device 2D are housed in a single housing. An electronic expansion valve can be used as the pressure regulating device 41C.

[0074] The control device 25D is configured to control the compressor 21, the pressure regulator 41C, and the expansion valve 27 based on the outputs of the pressure sensor 24 and the temperature sensor 26.

[0075] In the seventh embodiment, the pressure adjusting device 41C is an expansion valve connected between the third connection port P3 and the first connection port P1.

[0076] The control device 25D is configured to adjust the pressure using the first expansion valve (41C) and to control the second expansion valve 27 so as to increase the flow rate of liquid refrigerant from the heat exchanger 22 to the liquid port 31.

[0077] In the seventh embodiment, it is assumed that the operating frequency of the compressor 21 is constant, and an expansion valve 27 is provided in the suction section of the compressor 21. This reduces the suction pressure and the suction density, thereby reducing the refrigerant flow rate.

[0078] In the same manner as in the sixth embodiment, the seventh embodiment can also accommodate changes in refrigerant by configuring the control specifications so that the target pressure is automatically changed when the operator inputs the type of cylinder (pressure resistance of the cylinder) into the control device 25D. The electronic expansion valve (41C) and the expansion valve 27 can be controlled by the control device that controls the compressor originally installed in the recovery device, so only one control device is required.

[0079] 14 is a flowchart illustrating the control performed by the control device 25D in the seventh embodiment. Before starting the refrigerant recovery device 2D, the operator sets the type of refrigerant recovery cylinder or the type of refrigerant in the control device 25D. The control device 25D then automatically sets a target value corresponding to the refrigerant. When the operator starts the refrigerant recovery device 2D, in step S11, the control device 25D starts the compressor 21 and starts the fan 23 of the heat exchanger 22. Then, in step S12, the control device 25D determines whether the pressure detected by the pressure sensor 24 is higher than the target value.

[0080] When the pressure is higher than the target value (YES in S12), the control device 25D increases the opening of the electronic expansion valve (41C) to avoid protective shutdown of the compressor 21 due to high pressure (S13). On the other hand, when the pressure is lower than the target value (NO in S12), the control device 25D decreases the opening of the electronic expansion valve (41C) (S14) to increase the pressure and thereby increase the heat exchange amount.

[0081] Subsequently, in step S15, the control device 25D obtains the outlet temperature of the heat exchanger 22 from the temperature sensor 26 and determines whether the temperature is higher than the saturation temperature of the refrigerant. The saturation temperature can be obtained by using a map or calculation, etc., based on the pressure measured by the pressure sensor 24.

[0082] When the temperature is higher than the saturation temperature (YES in S15), the control device 25C reduces the opening of the expansion valve 27 at the suction port of the compressor 21 without changing the operating frequency of the compressor 21 (S16). This reduces the dryness fraction at the outlet of the heat exchanger 22. On the other hand, when the temperature is equal to or lower than the saturation temperature (NO in S15), the control device 25D increases the opening of the expansion valve 27 at the suction port of the compressor 21 without changing the operating frequency of the compressor 21 (S17). This increases the flow rate of liquid refrigerant.

[0083] In step S18, the control device 25D determines whether the switch of the refrigerant recovery device has been turned off by an operator. If the switch has not been turned off (NO in S18), the control device 25D executes the processes from step S12 onward again. If the switch has been turned off (YES in S18), the control device 25D stops the compressor 21 and the fan 23 of the heat exchanger 22.

[0084] By the above control, even if the operating frequency of the compressor 21 is constant, the refrigerant recovery speed can be increased by throttling the electronic expansion valve to increase the pressure, reducing the amount of refrigerant drawn into the compressor and lowering the dryness of the refrigerant at the outlet of the heat exchanger.

[0085] [Summary] The present disclosure will be summarized again with reference to the drawings.

[0086] (Item 1) The present disclosure relates to a cylinder pressure adjustment device 4 for adjusting the pressure inside a refrigerant recovery cylinder 3 when refrigerant from a refrigerant recovery target device is compressed by a compressor 21 and recovered in the refrigerant recovery cylinder 3. The cylinder pressure adjustment device 4 shown in Figures 1 and 2 includes a first connection port P1 connected to a service valve 13, 18 of the refrigerant recovery target device, a second connection port P2 communicating with the first connection port P1 and connected to the suction port of the compressor 21, a third connection port P3 connected to a gas port 32 of the refrigerant recovery cylinder 3, and a pressure adjustment device 41 connected between the first connection port P1 and the third connection port P3.

[0087] (Section 2) In another aspect, the present disclosure relates to a refrigerant recovery device. As shown in Figures 8 and 9, the refrigerant recovery device includes the cylinder pressure regulating device described in Section 1, a compressor 21, and a heat exchanger 22 that cools the refrigerant compressed by the compressor 21.

[0088] (Item 3) The refrigerant recovery device according to item 2 further includes a housing 60 that houses a cylinder pressure adjusting device (41), a compressor 21, and a heat exchanger 22, as shown in FIG.

[0089] 11 , in the refrigerant recovery device described in paragraph 3, the pressure adjustment device 41C is an expansion valve connected between the third connection port P3 and the first connection port P1. The refrigerant recovery device 2C further includes a control device 25C. The control device 25C is configured to adjust the opening of the expansion valve (41C) so that the pressure in the refrigerant recovery cylinder 3 does not exceed a target value, and to control the operating frequency of the compressor 21 so as to increase the flow rate of liquid refrigerant from the heat exchanger 22 to the liquid port 31 of the refrigerant recovery cylinder 3.

[0090] (Item 5) As shown in Fig. 12, the refrigerant recovery device described in item 4 further includes a pressure sensor 24 that detects the pressure of the refrigerant at the refrigerant outlet portion of the heat exchanger 22, and a temperature sensor 26 that detects the temperature of the refrigerant at the refrigerant outlet portion of the heat exchanger 22. As shown in Fig. 12, the control device 25C is configured to increase the opening of the expansion valve (41C) when the pressure detected by the pressure sensor 24 is higher than a target value. The control device 25C is configured to reduce the operating frequency of the compressor 21 when the temperature detected by the temperature sensor 26 is higher than the saturation temperature of the refrigerant.

[0091] (Item 6) In the refrigerant recovery device described in item 5, the control device 25C is configured to reduce the opening of the expansion valve (41C) when the pressure detected by the pressure sensor 24 is lower than a target value, as shown in Fig. 12. The control device 25C is configured to increase the operating frequency of the compressor 21 when the temperature detected by the temperature sensor 26 is lower than the saturation temperature of the refrigerant.

[0092] 13 , in the refrigerant recovery device described in paragraph 3, the pressure adjustment device 41C is a first expansion valve connected between the third connection port P3 and the first connection port P1. The refrigerant recovery device 2D further includes a second expansion valve 27 disposed at the refrigerant suction port of the compressor 21 and a control device 25D. The control device 25D is configured to adjust the opening of the first expansion valve (41C) so that the pressure in the refrigerant recovery cylinder 3 does not exceed a target value, and to control the second expansion valve 27 so as to increase the flow rate of liquid refrigerant from the heat exchanger 22 to the liquid port 31 of the refrigerant recovery cylinder 3.

[0093] 13 , in the refrigerant recovery device described in the seventh aspect, a refrigerant recovery device 2D further includes a pressure sensor 24 that detects the pressure of the refrigerant at the refrigerant outlet portion of the heat exchanger 22, and a temperature sensor 26 that detects the temperature of the refrigerant at the refrigerant outlet portion of the heat exchanger 22. The control device 25D is configured to increase the opening degree of the first expansion valve (41C) when the pressure detected by the pressure sensor 24 is higher than a target value. The control device 25D is configured to decrease the opening degree of the second expansion valve 27 when the temperature detected by the temperature sensor 26 is higher than the saturation temperature of the refrigerant.

[0094] (Item 9) In the refrigerant recovery device described in item 8, the control device 25D is configured to decrease the opening of the first expansion valve (41C) when the pressure detected by the pressure sensor 24 is lower than a target value. The control device 25D is configured to decrease the opening of the second expansion valve 27 when the temperature detected by the temperature sensor 26 is lower than the saturation temperature of the refrigerant.

[0095] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0096] 1 Refrigeration cycle device, 2, 2A, 2B, 2C, 2D Refrigerant recovery device, 3 Refrigerant recovery cylinder, 4, 4A, 4B Cylinder pressure adjustment device, 5 Gauge manifold, 5A, 5B, 5C Connection port, 11, 21 Compressor, 12 Outdoor heat exchanger, 13, 18 Service valve, 14, 17 Extension piping, 15, 27 Expansion valve, 16 Indoor heat exchanger, 22 Heat exchanger, 23 Fan, 24, 42 Pressure sensor, 25, 25C, 25D, 43 Control device, 26 Temperature sensor, 31 Liquid port, 31C, 41, 41A, 41B, 41C Pressure adjustment device, 32 Gas port, 51, 52, 53, 54, 56 Charge hose, 60 Housing, P1 First connection port, P2 Second connection port, P3 Third connection port.

Claims

1. A refrigerant recovery device, Compressor and, A heat exchanger for cooling the refrigerant compressed by the compressor, When the refrigerant of the refrigerant recovery device is compressed by the compressor and recovered into a refrigerant recovery cylinder, a cylinder pressure adjustment device is provided to adjust the pressure inside the refrigerant recovery cylinder, The system comprises a housing that accommodates the cylinder pressure regulating device, the compressor, and the heat exchanger, The cylinder pressure adjustment device is, A first connection port connected to the service valve of the refrigerant recovery device, A second connection port is connected to the first connection port and is connected to the suction port of the compressor, A third connection port connected to the gas port of the refrigerant recovery cylinder, It comprises a pressure regulating device connected between the aforementioned first connection port and the aforementioned third connection port, The pressure regulating device is a first expansion valve connected between the third connection port and the first connection port. The compressor further comprises a second expansion valve located at the refrigerant inlet, A refrigerant recovery device further comprises a control device configured to adjust the opening of the first expansion valve so that the pressure in the refrigerant recovery cylinder does not exceed a target value, and to control the second expansion valve so that the liquid refrigerant flow rate of the refrigerant flowing from the heat exchanger to the liquid port of the refrigerant recovery cylinder increases.

2. A pressure sensor for detecting the refrigerant pressure at the refrigerant outlet portion of the heat exchanger, The heat exchanger further comprises a temperature sensor for detecting the temperature of the refrigerant at the refrigerant outlet portion, The control device is configured to increase the opening of the first expansion valve when the pressure detected by the pressure sensor is higher than the target value. The refrigerant recovery apparatus according to claim 1, wherein the control device is configured to reduce the opening of the second expansion valve when the temperature detected by the temperature sensor is higher than the saturation temperature of the refrigerant.

3. The control device is configured to reduce the opening of the first expansion valve when the pressure detected by the pressure sensor is lower than the target value. The refrigerant recovery apparatus according to claim 2, wherein the control device is configured to reduce the opening of the second expansion valve when the temperature detected by the temperature sensor is lower than the saturation temperature of the refrigerant.

4. A refrigerant recovery device, Compressor and, A heat exchanger for cooling the refrigerant compressed by the compressor, When the refrigerant of the refrigerant recovery device is compressed by the compressor and recovered into a refrigerant recovery cylinder, a cylinder pressure adjustment device is provided to adjust the pressure inside the refrigerant recovery cylinder, The system comprises a housing that accommodates the cylinder pressure regulating device, the compressor, and the heat exchanger, The cylinder pressure adjustment device is, A first connection port connected to the service valve of the refrigerant recovery device, A second connection port is connected to the first connection port and is connected to the suction port of the compressor, A third connection port connected to the gas port of the refrigerant recovery cylinder, It comprises a pressure regulating device connected between the aforementioned first connection port and the aforementioned third connection port, The pressure regulating device is an expansion valve connected between the third connection port and the first connection port. The refrigerant recovery device is A control device configured to adjust the opening of the expansion valve so that the pressure in the refrigerant recovery cylinder does not exceed a target value, and to control the operating frequency of the compressor so that the liquid refrigerant flow rate of the refrigerant flowing from the heat exchanger to the liquid port of the refrigerant recovery cylinder increases, A pressure sensor for detecting the refrigerant pressure at the refrigerant outlet portion of the heat exchanger, The heat exchanger further comprises a temperature sensor for detecting the temperature of the refrigerant at the refrigerant outlet portion, The control device is configured to increase the opening of the expansion valve when the pressure detected by the pressure sensor is higher than the target value. The control device is configured to reduce the operating frequency of the compressor when the temperature detected by the temperature sensor is higher than the saturation temperature of the refrigerant, and is a refrigerant recovery device.

5. The control device is configured to reduce the opening of the expansion valve when the pressure detected by the pressure sensor is lower than a target value, The refrigerant recovery apparatus according to claim 4, wherein the control device is configured to increase the operating frequency of the compressor when the temperature detected by the temperature sensor is lower than the saturation temperature of the refrigerant.