Oil return control method for refrigeration system, refrigeration system and environmental chamber

Abstract

The embodiment of the present invention discloses an oil return control method for a refrigeration system, a refrigeration system, and an environmental box. The oil return control method includes: obtaining the working mode of the refrigeration system, the working state of the first compressor in the refrigeration system, and the working state of the second compressor in the refrigeration system; according to the working mode and the working state of the first compressor, controlling the working state of the solenoid valve, the throttle valve, and the oil return assembly in the pipeline connected to the first compressor; according to the working mode and the working state of the second compressor, controlling the working state of the solenoid valve, the throttle valve, and the oil return assembly in the pipeline connected to the second compressor to control the oil return of the refrigeration system; wherein the pipeline connected to the first compressor and the pipeline connected to the second compressor are both connected to the heat exchanger in the refrigeration system. The oil return control method, refrigeration system, and environmental box for the refrigeration system provided by the embodiment of the present invention can improve control reliability.

Description

Technical Field

[0001] The embodiments of the present invention relate to oil return technology, and in particular to an oil return control method of a refrigeration system, a refrigeration system and an environmental chamber. Background Art

[0002] For the refrigeration system of an environmental chamber such as a constant temperature and humidity environmental chamber, it is necessary to ensure the long-term constant temperature and humidity of the environmental chamber while meeting the cooling rate requirements of the environmental chamber. This results in a large refrigerant flow rate when the temperature in the chamber is reduced, and a small refrigerant flow rate when the temperature and humidity in the chamber are constant. When the constant refrigerant flow rate is small, the refrigerant flow rate in the refrigeration system is small, and the lubricating oil in the refrigerant will be deposited in the pipeline, resulting in a decrease in the oil return of the compressor, affecting the normal operation of the refrigeration system. Therefore, in order to ensure the normal operation of the refrigeration system, the oil return of the refrigeration system needs to be controlled.

[0003] At present, the existing oil return method of the refrigeration system usually relies on oil filtration at the compressor exhaust port and returning oil through an oil return bend set in the return air pipeline. However, this method has the problem of some oil being brought into the pipeline or the oil return bend, and the compressor will still have an oil shortage problem after a long period of stability. Summary of the invention

[0004] The embodiment of the present invention provides an oil return control method of a refrigeration system, a refrigeration system and an environmental chamber to solve the problem of oil shortage in a compressor.

[0005] An embodiment of the present invention provides an oil return control method for a refrigeration system, comprising:

[0006] Acquire an operating mode of the refrigeration system, an operating state of a first compressor in the refrigeration system, and an operating state of a second compressor in the refrigeration system;

[0007] According to the working mode and the working state of the first compressor, the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the first compressor is controlled;

[0008] According to the working mode and the working state of the second compressor, the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the second compressor is controlled to perform oil return control on the refrigeration system;

[0009] Wherein, the pipeline connected to the first compressor and the pipeline connected to the second compressor are both connected to the heat exchanger in the refrigeration system.

[0010] Optionally, according to the working mode and the working state of the first compressor, controlling the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the first compressor includes:

[0011] When the working mode is the cooling mode or the low temperature constant mode, and the first compressor is started, the main circuit solenoid valve in the pipeline connected to the first compressor is controlled to be closed, the plate change solenoid valve is opened, the oil return component is closed, the main circuit throttle valve is closed, and the cold bypass solenoid valve is closed;

[0012] When the working mode is the high temperature constant mode, the main circuit solenoid valve in the pipeline connected to the first compressor is controlled to open, the plate change solenoid valve is closed, the return oil component is opened, the bypass solenoid valve is opened, and the cold bypass solenoid valve is closed, and the opening frequency of the return oil component in the pipeline connected to the first compressor and the opening degree of the main circuit throttle valve in the pipeline connected to the first compressor are adjusted;

[0013] When the working mode is the humidity mode, the main solenoid valve in the pipeline connected to the first compressor is controlled to open, the plate change solenoid valve is closed, the return oil assembly is opened, the bypass solenoid valve is closed, and the cold bypass solenoid valve is closed, and the opening frequency of the return oil assembly in the pipeline connected to the first compressor and the opening degree of the main throttle valve in the pipeline connected to the first compressor are adjusted.

[0014] Optionally, adjusting the opening frequency of the oil return assembly in the pipeline connected to the first compressor and the opening degree of the main throttle valve in the pipeline connected to the first compressor includes:

[0015] The opening frequency of the oil return assembly in the pipeline connected to the first compressor is adjusted to first increase and then decrease, and the opening degree of the main throttle valve in the pipeline connected to the first compressor is adjusted to first increase and then decrease.

[0016] Optionally, also include:

[0017] When the working mode is the cooling mode or the low temperature constant mode, if the actual exhaust temperature of the first compressor exceeds the preset exhaust temperature, the cold bypass solenoid valve in the pipeline connected to the first compressor is controlled to open.

[0018] Optionally, according to the working mode and the working state of the second compressor, controlling the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the second compressor includes:

[0019] When the working mode is cooling mode or low temperature constant mode and the second compressor is started, the main solenoid valve in the pipeline connected to the second compressor is controlled to open, the main throttle valve is opened, the return oil component is closed, and the cold bypass solenoid valve is closed.

[0020] Optionally, also include:

[0021] When the working mode is the cooling mode or the low temperature constant mode, if the actual exhaust temperature of the second compressor exceeds the preset exhaust temperature, the cold bypass solenoid valve in the pipeline connected to the second compressor is controlled to open.

[0022] In a second aspect, an embodiment of the present invention provides a refrigeration system, comprising: a first compressor, a second compressor, and solenoid valves, throttle valves and oil return assemblies corresponding to the first compressor and the second compressor, respectively. The solenoid valves, throttle valves and oil return assemblies corresponding to each compressor are arranged in a pipeline connected to the corresponding compressor, and the solenoid valves, throttle valves and oil return assemblies corresponding to each compressor are electrically connected to a controller, and the controller is used to execute the oil return control method as described in the first aspect.

[0023] Optionally, the oil return assembly includes a hot gas quick opening valve or an electronic expansion valve.

[0024] Optionally, the solenoid valves corresponding to each compressor include a main circuit solenoid valve and a cold bypass solenoid valve.

[0025] In a third aspect, an embodiment of the present invention provides an environmental chamber, which is refrigerated by the refrigeration system described in the second aspect.

[0026] The oil return control method, refrigeration system and environmental box of the refrigeration system provided by the embodiment of the present invention, by obtaining the working mode of the refrigeration system, the working state of the first compressor in the refrigeration system and the working state of the second compressor in the refrigeration system; according to the working mode and the working state of the first compressor, the working state of the solenoid valve, throttle valve and oil return assembly in the pipeline connected to the first compressor is controlled; according to the working mode and the working state of the second compressor, the working state of the solenoid valve, throttle valve and oil return assembly in the pipeline connected to the second compressor is controlled to control the oil return of the refrigeration system; wherein the pipeline connected to the first compressor and the pipeline connected to the second compressor are both connected to the heat exchanger in the refrigeration system. The oil return control method, refrigeration system and environmental box of the refrigeration system provided by the embodiment of the present invention, according to the working mode and the working state of each compressor, the working state of the solenoid valve, throttle valve and oil return assembly in the pipeline connected to each compressor is controlled, such as controlling the opening and closing of various valves, so that the oil in the pipeline can fully flow back to the compressor, ensuring the reliable oil return of the compressor, which can solve the problem of part of the oil being brought into the pipeline in the prior art, causing the compressor to lack oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow chart of an oil return control method for a refrigeration system provided in Embodiment 1 of the present invention;

[0028] Figure 2 is a flow chart of an oil return control method for a refrigeration system provided in Embodiment 2 of the present invention;

[0029] Figure 3 It is a structural schematic diagram of a refrigeration system provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0031] Embodiment 1

[0032] Figure 1 1 is a flow chart of a method for controlling oil return of a refrigeration system provided in Embodiment 1 of the present invention. This embodiment can be applied to controlling oil return of a refrigeration system. The method can be executed by a controller in the refrigeration system. The method specifically includes the following steps:

[0033] Step 110: Acquire the working mode of the refrigeration system, the working state of the first compressor in the refrigeration system, and the working state of the second compressor in the refrigeration system.

[0034] The controller in the refrigeration system can receive an external signal, which can include information about the working mode of the refrigeration system to determine the working mode of the refrigeration system. The controller is electrically connected to the first compressor and the second compressor in the refrigeration system to obtain the working state of the first compressor and the working state of the second compressor.

[0035] Step 120: Control the working states of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the first compressor according to the working mode and the working state of the first compressor.

[0036] Specifically, when the working mode is the cooling mode or the low-temperature constant mode and the first compressor is started, the main solenoid valve in the pipeline connected to the first compressor is controlled to be closed, the plate change solenoid valve is opened, the oil return assembly is closed, the main throttle valve is closed, and the cold bypass solenoid valve is closed to realize the oil return of the first compressor.

[0037] Step 130: According to the working mode and the working state of the second compressor, the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the second compressor is controlled to perform oil return control on the refrigeration system.

[0038] The pipeline connected to the first compressor and the pipeline connected to the second compressor are both connected to the heat exchanger in the refrigeration system. Specifically, when the working mode is the cooling mode or the low temperature constant mode, and the second compressor is started, the main circuit solenoid valve, the main circuit throttle valve, the oil return assembly, and the cold bypass solenoid valve in the pipeline connected to the second compressor are controlled to open, so as to realize the oil return of the second compressor.

[0039] The oil return control method of the refrigeration system provided in this embodiment obtains the working mode of the refrigeration system, the working state of the first compressor in the refrigeration system, and the working state of the second compressor in the refrigeration system; according to the working mode and the working state of the first compressor, the working state of the solenoid valve, the throttle valve, and the oil return assembly in the pipeline connected to the first compressor is controlled; according to the working mode and the working state of the second compressor, the working state of the solenoid valve, the throttle valve, and the oil return assembly in the pipeline connected to the second compressor is controlled to control the oil return of the refrigeration system; wherein the pipeline connected to the first compressor and the pipeline connected to the second compressor are both connected to the heat exchanger in the refrigeration system. The oil return control method of the refrigeration system provided in this embodiment controls the working state of the solenoid valve, the throttle valve, and the oil return assembly in the pipeline connected to each compressor according to the working mode and the working state of each compressor, such as controlling the opening and closing of various valves, so that the oil in the pipeline can fully flow back to the compressor, ensuring the reliable oil return of the compressor, which can solve the problem of part of the oil being brought into the pipeline in the prior art, resulting in oil shortage in the compressor.

[0040] Embodiment 2

[0041] Figure 2 1 is a flow chart of a method for controlling oil return of a refrigeration system provided in Embodiment 2 of the present invention. This embodiment can be applied to controlling oil return of a refrigeration system. The method can be executed by a controller in the refrigeration system. The method specifically includes the following steps:

[0042] Step 210: Acquire the working mode of the refrigeration system, the working state of the first compressor in the refrigeration system, and the working state of the second compressor in the refrigeration system.

[0043] The controller in the refrigeration system can receive an external signal, which can include information about the working mode of the refrigeration system to determine the working mode of the refrigeration system. The controller is electrically connected to the first compressor and the second compressor in the refrigeration system to obtain the working state of the first compressor and the working state of the second compressor.

[0044] Step 220, when the working mode is the cooling mode or the low temperature constant mode, and the first compressor is started, the main solenoid valve in the pipeline connected to the first compressor is controlled to be closed, the plate change solenoid valve is opened, the return oil component is closed, the main throttle valve is closed, and the cold bypass solenoid valve is closed.

[0045] Specifically, when the working mode is the cooling mode or the low temperature constant mode, if the actual exhaust temperature of the first compressor exceeds the preset exhaust temperature, the cold bypass solenoid valve in the pipeline connected to the first compressor is controlled to open.

[0046] Step 230, when the working mode is the high temperature constant mode, the main solenoid valve in the pipeline connected to the first compressor is controlled to open, the plate change solenoid valve is closed, the return oil assembly is opened, the bypass solenoid valve is opened, and the cold bypass solenoid valve is closed, and the opening frequency of the return oil assembly in the pipeline connected to the first compressor and the opening degree of the main throttle valve in the pipeline connected to the first compressor are adjusted.

[0047] Specifically, the opening frequency of the oil return component in the pipeline connected to the first compressor is adjusted to increase first and then decrease, and the opening degree of the main throttle valve in the pipeline connected to the first compressor is adjusted to increase first and then decrease. During the adjustment process, the opening frequency and the opening degree are both reduced to their respective corresponding preset values ​​and no longer change. The specific size of the preset value can be determined according to the actual oil return control requirements and is not limited here.

[0048] Step 240, when the working mode is the humidity mode, control the main solenoid valve in the pipeline connected to the first compressor to open, the plate change solenoid valve to close, the return oil assembly to open, the bypass solenoid valve to close, and the cold bypass solenoid valve to close, and adjust the opening frequency of the return oil assembly in the pipeline connected to the first compressor and the opening degree of the main throttle valve in the pipeline connected to the first compressor.

[0049] The adjustment of the opening frequency and the opening degree may refer to the description in step 230 and will not be repeated here.

[0050] Step 250, when the working mode is the cooling mode or the low temperature constant mode and the second compressor is started, the main solenoid valve in the pipeline connected to the second compressor is controlled to open, the main throttle valve is controlled to open, the return oil component is controlled to close, and the cold bypass solenoid valve is controlled to close.

[0051] Specifically, when the working mode is the cooling mode or the low temperature constant mode, if the actual exhaust temperature of the second compressor exceeds the preset exhaust temperature, the cold bypass solenoid valve in the pipeline connected to the second compressor is controlled to open.

[0052] The oil return control method for the refrigeration system provided in this embodiment controls the working status of the solenoid valves, throttle valves and oil return components in the pipelines connected to each compressor according to the working mode and the working status of each compressor, such as controlling the on and off of various valve components so that the oil in the pipeline can fully flow back to the compressor, ensuring reliable oil return of the compressor, and can solve the problem of partial oil being brought into the pipeline in the prior art, resulting in oil shortage in the compressor.

[0053] Embodiment 3

[0054] Figure 3 Schematic diagram of a refrigeration system provided by Embodiment 3 of the present invention. Figure 3 The refrigeration system includes: a first compressor, a second compressor, and solenoid valves, throttle valves and oil return components corresponding to the first compressor and the second compressor respectively.

[0055] Among them, the solenoid valve, throttle valve and oil return assembly corresponding to each compressor are arranged in the pipeline connected to the corresponding compressor, and the solenoid valve, throttle valve and oil return assembly corresponding to each compressor are electrically connected to the controller, and the controller is used to execute the oil return control method described in any embodiment of the present invention.

[0056] Specifically, when the refrigeration system works in the cooling mode, a compressor 1, namely the above-mentioned first compressor CM1, is started, and the controller controls the main circuit solenoid valve 5 corresponding to the compressor 1 to be closed, the plate exchange solenoid valve 7 to be opened, the return oil component 25 to be closed, the main circuit throttle valve 6 to be closed, and the cold bypass solenoid valve 11 to be closed. The high-temperature and high-pressure refrigerant flows out from the exhaust port of the first compressor CM1, passes through the oil separator and enters the first condenser 2 for heat exchange and condensation into high-pressure liquid refrigerant. The liquid refrigerant flows out from the first condenser 2 and flows through the drying filter, the sight glass and the plate exchange solenoid valve 7 in turn. After throttling by the throttle valve before the plate exchange, it becomes a low-temperature and low-pressure gas-liquid mixed refrigerant, and then enters the plate heat exchanger 14 for heat exchange, becomes a gaseous refrigerant and returns to the compressor suction port, completing the cycle of a section of refrigerant. When the first compressor CM1 is started for a period of time and the plate heat exchanger 14 is fully cooled, the second compressor 15, i.e., the second compressor CM2, is started. The controller controls the main electromagnetic valve 18 corresponding to the second compressor 15 to open, the main throttle valve 19 to open, the oil return component 26 to close, and the cold bypass electromagnetic valve 21 to close. The second compressor 15 compresses the second refrigerant into a high-temperature and high-pressure gas, and then enters the second precooler 24 to exchange heat with the cooling water, and is cooled into a medium-temperature and high-pressure gaseous refrigerant. Then, it passes through the oil separator and enters the plate heat exchanger 14 for further heat exchange, and is condensed into a high-pressure liquid refrigerant and flows out of the plate heat exchanger. The high-pressure liquid refrigerant passes through the main electromagnetic valve 18 and is throttled by the main throttle valve 19 to become a low-temperature and low-pressure gas-liquid mixed refrigerant, and then enters the second evaporator 20 for heat exchange and refrigeration to cool the box. Finally, the low-pressure gaseous refrigerant coming out of the second evaporator 20 returns to the compressor suction port to complete the second refrigerant cycle. In the cooling mode, when the exhaust temperature of the first stage compressor 1 and the second stage compressor 15 exceeds the set value, the controller controls the cold side solenoid valves 11 and 21 corresponding to each compressor to open, and the cold side thermal expansion valves 12 and 22 to open, thereby reducing the suction temperature of the compressor, and then reducing the exhaust temperature of the compressor. In the cooling mode, the refrigerant flow is relatively large. Even if the compressor is directly started to cool down without preheating, the lubricating oil in the compressor oil tank is all brought into the pipeline by the refrigerant. Due to the large refrigerant flow, the lubricating oil can also be brought back to the suction port of the compressor, thereby realizing oil return.

[0057] The high temperature constant mode and the low temperature constant mode are divided according to the constant temperature in the box. For example, when the temperature in the box is constant above 0°C, it is the high temperature constant mode, and when it is constant below 0°C, it is the low temperature constant mode. In the high temperature constant mode, the first stage compressor 1 is started and the second stage compressor 15 is turned off.

[0058] In the high temperature constant mode, the controller controls the main electromagnetic valve 5 corresponding to the compressor 1 to open, the main throttle valve 6 to open, the plate change electromagnetic valve 7 to close, the oil return assembly 25 to open, the bypass electromagnetic valve 10 to open, and the cold bypass electromagnetic valve 11 to close. At this time, the liquid refrigerant condensed by the condenser 2 will pass through the main electromagnetic valve 5, and after being throttled by the main throttle valve 6, it will enter the evaporator 8 to exchange heat with the box. After the heat exchange, the gaseous refrigerant will return to the compressor after passing through the bypass electromagnetic valve 10. When the high temperature is constant, the cooling capacity required in the box is small. At this time, the controller adjusts the opening of the main throttle valve 6 to be small. The flow rate of the refrigerant in the evaporator 8 and the return pipe at the outlet of the evaporator is very slow. The suction pressure detected by the low pressure sensor 13 is very low. At this time, the lubricating oil brought into the pipeline by the refrigerant will be deposited in the evaporator 8 and the return pipe of the evaporator. After a long period of constant temperature, the lubricating oil deposited in the evaporator and the return pipe will increase, and the compressor will be short of oil. In order to solve the above-mentioned problem of difficult oil return, an oil return assembly 25 is arranged between the compressor exhaust port and the evaporator inlet, and the oil return assembly 25 includes a section of hot gas quick opening valve 3 and a section of hot gas capillary 4. When entering the high temperature constant mode, the controller adjusts the opening frequency of a section of hot gas quick opening valve 3 to be relatively large. At this time, the high temperature gaseous refrigerant passing through a section of hot gas capillary 4 is relatively large, and then mixed with the low temperature refrigerant after throttling by the main throttle valve 6 and enters the evaporator. Since the refrigeration capacity of the high and low temperature mixed refrigerant is less than the refrigeration capacity of the low temperature refrigerant after throttling before, and the opening degree of the main throttle valve 6 is relatively large, the refrigerant flow rate entering the evaporator after mixing will be relatively large, and the lubricating oil originally deposited on the evaporator and the return air pipe will also be flushed back to the compressor to realize the oil return on the pipeline. At this time, a section of low pressure sensor 13 detects a relatively high pressure. If the compressor runs at a large flow rate for a long time, the power consumption of the compressor will increase. In order to solve the problem of high power consumption of the compressor, the opening frequency of a section of hot gas quick-opening valve 3 is controlled to be slowly reduced through the controller to slowly reduce the amount of hot gas entering the evaporator 8. At the same time, the opening degree of the main throttle valve 6 is also controlled to be slowly reduced, so as to keep the temperature in the box stable. The pressure detected by a section of low-pressure sensor 13 will slowly decrease. When it drops to the preset pressure, the opening frequency of a section of hot gas quick-opening valve 3 is controlled to no longer decrease. At the same time, the opening degree of the main throttle valve 6 is also controlled to no longer decrease. The power consumption of the compressor is relatively small, and the lubricating oil in the evaporator and the return air pipeline is not easy to deposit, thereby achieving long-term high temperature constancy and the function of regular oil return.When the high temperature is constant for the set time, the controller controls the first section of the hot gas quick-opening valve 3 to slowly increase the opening frequency, and the main throttle valve 6 gradually increases the opening degree, and the flow entering the first section of the evaporator 8 will increase, so that the lubricating oil deposited in the first section of the evaporator 8 and the return air pipeline can be brought back to the first section of the compressor 1. At this time, the suction pressure detected by the first section of the low-pressure sensor 13 increases. When it increases to the preset pressure, the controller controls the first section of the hot gas quick-opening valve 3 to stop increasing the opening frequency, and the main throttle valve 6 stops increasing the opening degree. After a period of time, the lubricating oil in the first section of the evaporator 8 and the return air pipe is flushed back to the first section of the compressor 1, and the opening frequency of the first section of the hot gas quick-opening valve 3 slowly returns to the original opening state, and the main throttle valve 6 returns to its original opening degree.

[0059] In the low temperature constant mode, the state is the same as that in the cooling mode, except that in the low temperature constant mode, the refrigeration capacity required in the box is very small, so the opening of the main throttle valve 19 is very small. As in the high temperature constant mode, the refrigerant flow entering the second stage evaporator 20 is very small, and lubricating oil is easily deposited in the second stage evaporator 20 and the return air pipeline, resulting in oil shortage in the second stage compressor 15. Therefore, in order to solve the problem of difficult oil return in the low temperature constant mode, an oil return component 26 is added between the high pressure side and the inlet of the second stage evaporator 20. The oil return component 26 includes a second stage hot gas quick opening valve 16 and a second stage hot gas capillary 17. When entering the low temperature constant mode, the adjustment logic of the second stage hot gas quick opening valve 16 and the main throttle valve 19 is the same as that in the high temperature constant mode. When the pressure detected by the second stage low pressure sensor 23 reaches the set pressure, the opening of the hot gas quick opening valve 16 and the main throttle valve 19 is determined. Among them, the hot gas quick opening valve in each oil return component can also be replaced by an electronic expansion valve.

[0060] The difference between the humidity mode and the high temperature constant mode is that the bypass solenoid valve 10 corresponding to the first compressor 1 is closed, and the refrigerant flowing out of the first evaporator 8 returns to the suction port of the first compressor 1 after passing through the evaporation pressure regulating valve 9. Since the humidity in the box needs to be constant for a long time, to prevent the first evaporator 8 from frosting and affecting the heat exchange, the evaporation pressure regulating valve 9 is required to increase the evaporation pressure in the first evaporator 8 and increase the surface temperature of the first evaporator 8, thereby reducing the frosting of the first evaporator 8. The other control processes of the humidity mode are the same as those of the high temperature constant mode, and will not be repeated here.

[0061] This embodiment also provides an environmental box, and the environmental box is refrigerated by the refrigeration system described in any embodiment of the present invention.

[0062] The refrigeration system and environmental chamber provided in this embodiment belong to the same inventive concept as the oil return control method for the refrigeration system provided in any embodiment of the present invention, and have corresponding beneficial effects. For technical details not detailed in this embodiment, please refer to the oil return control method for the refrigeration system provided in any embodiment of the present invention.

[0063] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for controlling oil return in a refrigeration system, characterized in that: include: Acquire an operating mode of a refrigeration system, an operating state of a first compressor in the refrigeration system, and an operating state of a second compressor in the refrigeration system; According to the working mode and the working state of the first compressor, controlling the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the first compressor; According to the working mode and the working state of the second compressor, the working state of the solenoid valve, the throttle valve and the oil return component in the pipeline connected to the second compressor is controlled to perform oil return control on the refrigeration system; The controlling the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the first compressor according to the working mode and the working state of the first compressor comprises: When the working mode is the cooling mode or the low temperature constant mode, and the first compressor is started, the main circuit solenoid valve in the pipeline connected to the first compressor is controlled to be closed, the plate change solenoid valve is opened, the hot gas quick opening valve of the oil return component is closed, the main circuit throttle valve is closed, and the cold bypass solenoid valve is closed; When the working mode is the high temperature constant mode, the main circuit solenoid valve in the pipeline connected to the first compressor is controlled to open, the plate change solenoid valve is controlled to close, the hot gas quick opening valve of the oil return component is controlled to open, the bypass solenoid valve is controlled to open, and the cold bypass solenoid valve is controlled to close, and the opening frequency of the oil return component in the pipeline connected to the first compressor and the opening degree of the main circuit throttle valve in the pipeline connected to the first compressor are adjusted; The connection relationship of each component in the pipeline connected to the first compressor is as follows: the outlet of the first condenser is connected to the first end of the cold bypass solenoid valve, the first end of the main solenoid valve and the first end of the plate heat exchanger solenoid valve; the second end of the cold bypass solenoid valve is connected to the first end of the cold bypass thermal expansion valve; the second end of the main solenoid valve is connected to the first end of the main throttle valve, the second end of the main throttle valve is connected to the first end of the evaporator, and the second end of the evaporator is connected to the first end of the bypass solenoid valve; the second end of the plate heat exchanger solenoid valve is connected to the first inlet of the plate heat exchanger; the second end of the cold bypass thermal expansion valve, the second end of the bypass solenoid valve, and the second outlet of the plate heat exchanger are connected to the inlet of the first compressor; the outlet of the first compressor is connected to the first end of the hot gas quick-opening valve of the oil return component and the inlet of the condenser, the second end of the hot gas quick-opening valve of the oil return component is connected to the first end of the hot gas capillary of the oil return component, and the second end of the hot gas capillary of the oil return component is connected to the second end of the main throttle valve and the first end of the plate heat exchanger solenoid valve.

2. The oil return control method according to claim 1, characterized in that: The controlling the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the first compressor according to the working mode and the working state of the first compressor also includes: When the working mode is the humidity mode, the main solenoid valve in the pipeline connected to the first compressor is controlled to open, the plate change solenoid valve is closed, the hot gas quick-opening valve of the return oil component is opened, the bypass solenoid valve is closed, and the cold bypass solenoid valve is closed, and the opening frequency of the hot gas quick-opening valve of the return oil component in the pipeline connected to the first compressor and the opening degree of the main throttle valve in the pipeline connected to the first compressor are adjusted.

3. The oil return control method according to claim 1, characterized in that: The controlling the working state of the solenoid valve, the throttle valve and the oil return assembly in the pipeline connected to the second compressor according to the working mode and the working state of the second compressor comprises: When the working mode is the cooling mode or the low-temperature constant mode and the second compressor is started, the second-stage main line solenoid valve in the pipeline connected to the second compressor is controlled to open, the second-stage main line throttle valve is opened, the second-stage hot gas quick-opening valve of the return oil component is closed, and the second-stage cold bypass solenoid valve is closed.

4. The oil return control method according to claim 1, characterized in that: The adjusting the opening frequency of the oil return assembly in the pipeline connected to the first compressor and the opening degree of the main throttle valve in the pipeline connected to the first compressor includes: The opening frequency of the oil return component in the pipeline connected to the first compressor is adjusted to first increase and then decrease, and the opening degree of the main throttle valve in the pipeline connected to the first compressor is adjusted to first increase and then decrease.

5. The oil return control method according to claim 1, characterized in that: Also includes: When the working mode is the cooling mode or the low temperature constant mode, if the actual exhaust temperature of the first compressor exceeds the preset exhaust temperature, the cold bypass solenoid valve in the pipeline connected to the first compressor is controlled to open.

6. The oil return control method according to claim 1, characterized in that: Also includes: When the working mode is the cooling mode or the low temperature constant mode, if the actual exhaust temperature of the second compressor exceeds the preset exhaust temperature, the second-stage cold bypass solenoid valve in the pipeline connected to the second compressor is controlled to open.

7. A refrigeration system, characterized in that: include: The first compressor, the second compressor, the first compressor and the second compressor respectively correspond to the solenoid valve, the throttle valve and the oil return assembly, the solenoid valve, the throttle valve and the oil return assembly corresponding to each compressor are arranged in the pipeline connected to the corresponding compressor, and the solenoid valve, the throttle valve and the oil return assembly corresponding to each compressor are electrically connected to the controller, and the controller is used to execute the oil return control method as described in any one of claims 1-6.

8. The refrigeration system according to claim 7, characterized in that: The oil return assembly includes a hot gas quick-opening valve or an electronic expansion valve.

9. The refrigeration system according to claim 7, characterized in that: The solenoid valves corresponding to each compressor include a main circuit solenoid valve and a cold bypass solenoid valve.

10. An environmental chamber, characterized in that: The environmental chamber is cooled by the refrigeration system described in any one of claims 7-9.

Images