Refrigerating system, control method thereof and testing equipment

Abstract

The invention relates to a refrigerating system and a control method and test equipment thereof, the refrigerating system comprises a first refrigerating module, and the first refrigerating module comprises a first compressor, an oil separator, a condensing heat exchanger, a first expansion valve, a load evaporator, an oil charging flow path, a first valve, an oil discharging flow path and a second valve which are sequentially connected to form a first refrigerating loop. The oil filling flow path is communicated with an air return opening of the first compressor, the first valve is arranged on the oil filling flow path and used for controlling whether the oil filling flow path supplements new oil to the first compressor or not, the oil discharging flow path is communicated with an oil return opening of the oil separator, and the second valve is arranged on the oil discharging flow path and used for controlling whether the oil discharging flow path discharges old oil flowing out of the oil return opening or not. According to the technical scheme, the first compressor can change oil efficiently, the first refrigeration module does not need to be started and stopped frequently in the oil change process, refrigerant does not need to be injected repeatedly, normal refrigeration work of the first refrigeration module is not affected, and the working efficiency of the refrigeration system can be improved.

Description

Technical Field

[0001] The present application relates to the field of refrigeration technology, and in particular to a refrigeration system and a control method and testing equipment thereof. Background Art

[0002] As the environmental requirements for semiconductor chip packaging testing become higher and higher, test equipment is now required to provide a test environment with a temperature range of -65℃ to 150℃ or a wider range to test and verify the stability and reliability of the chip in high and low temperature environments. Currently, the industry mainstream uses a refrigeration system combined with a heater to control the test environment temperature.

[0003] In a high-temperature test environment, when the refrigeration system is running, the lubricating oil that enters the load evaporator with the refrigerant is easily deteriorated due to being in a high-temperature environment for a long time, the viscosity of the lubricating oil decreases, the lubrication effect deteriorates, and it cannot provide effective lubrication protection, increasing the risk of compressor wear. In related technologies, in order to achieve compressor oil change, the compressor needs to be started and stopped repeatedly, and the refrigerant needs to be added multiple times, which not only has low oil change efficiency, but also affects the normal operation of the refrigeration system. Summary of the invention

[0004] Based on this, it is necessary to provide a refrigeration system and its control method and testing equipment to address the problem that the oil change efficiency of the compressor in the refrigeration system is low and affects the normal operation of the refrigeration system.

[0005] In a first aspect, the present application provides a refrigeration system, comprising:

[0006] The first refrigeration module comprises:

[0007] A first compressor, an oil separator, a condensing heat exchanger, a first expansion valve and a load evaporator are sequentially connected to form a first refrigeration circuit; and

[0008] an oil filling flow path and a first valve, the oil filling flow path being connected to the air return port of the first compressor, the first valve being arranged on the oil filling flow path and being used to control whether the oil filling flow path replenishes new oil to the first compressor;

[0009] An oil drain flow path and a second valve, wherein the oil drain flow path is connected to the oil return port of the oil separator, and the second valve is arranged on the oil drain flow path to control whether the oil drain flow path discharges the old oil flowing out through the oil return port.

[0010] In some embodiments, the refrigeration system further includes an oil return flow path and a third valve, the oil return port of the oil separator is connected to the air return port of the first compressor via the oil return flow path, and the third valve is disposed in the oil return flow path;

[0011] The refrigeration system has an oil return mode and an oil change mode. The third valve is used to open in the oil return mode to return oil to the first compressor; the first valve and the second valve are used to open in the oil change mode to change oil for the first compressor.

[0012] In some embodiments, the first refrigeration module further comprises an oil storage tank and / or an oil collecting tank;

[0013] The oil storage tank is used to store new oil, and the oil filling flow path connects the oil outlet of the oil storage tank with the air return port of the first compressor; the oil storage tank has an oil filling port and an oil filling valve for opening and closing the oil filling port;

[0014] The oil collecting tank is used to store old oil, the oil drain path connects the oil return port (h) of the oil separator with the oil inlet of the oil collecting tank, and the oil collecting tank has an oil discharge port and an oil discharge valve for opening and closing the oil discharge port.

[0015] In some embodiments, the oil storage tank has an air vent, which is located above the oil outlet of the oil storage tank and is connected to the air return port of the first compressor;

[0016] The oil collecting tank has an air extraction port, and is communicated with an air return port of the first compressor.

[0017] In some embodiments, the first refrigeration module further includes an oil filling monitor, the oil filling monitor being used to obtain oil filling amount information representing the amount of new oil added to the first compressor via the oil filling flow path; and / or,

[0018] The first refrigeration module further includes an oil drain monitor, which is used to obtain oil drain quantity information representing the quantity of old oil discharged to the outside through the oil drain flow path.

[0019] In some embodiments, the oil filling monitor includes an oil filling level meter and / or an oil filling flow meter; the oil filling level meter is arranged on an oil storage tank connected to the oil filling flow path, and the oil filling amount information includes oil level information of the new oil in the oil storage tank obtained by the oil filling level meter; the oil filling flow meter is arranged on the oil filling flow path, and the oil filling amount information includes oil flow information of the new oil in the oil filling flow path obtained by the oil filling flow meter;

[0020] The oil drain monitor includes an oil drain level meter and / or an oil drain flow meter; the oil drain level meter is arranged on an oil collecting tank connected to the oil drain flow path, and the oil drain quantity information includes the oil level information of the old oil in the oil collecting tank obtained by the oil drain level meter; the oil drain flow meter is arranged on the oil drain flow path, and the oil drain quantity information includes the oil flow information of the old oil in the oil drain flow path obtained by the oil drain flow meter.

[0021] In some embodiments, the first refrigeration module further includes an oil quality monitor, and the oil quality monitor is used to monitor whether the quality of the oil separated by the oil separator is qualified;

[0022] The oil quality monitor is arranged on a flow path connected to the oil return port of the oil separator.

[0023] In some embodiments, the oil quality monitor includes a sight glass, which is used to display the color of the oil separated by the oil separator.

[0024] In some embodiments, the refrigeration system also includes a second refrigeration module, which includes a second compressor, a condenser, and a second expansion valve connected in sequence to form a second refrigeration circuit. The condensing heat exchanger heat exchanges the first refrigeration circuit and the second refrigeration circuit, and is located between the second expansion valve and the second compressor on the second refrigeration circuit.

[0025] In a second aspect, the present application provides a control method for a refrigeration system, which is applied to a refrigeration system as described in any of the above embodiments, and the control method includes:

[0026] Start the refrigeration system;

[0027] judging whether the refrigeration system meets the oil change start condition based on the oil quality information of the refrigeration system and / or the operation time of the refrigeration system; if the refrigeration system meets the oil change start condition, opening the first valve and the second valve to enter the oil change mode;

[0028] Whether the refrigeration system meets the oil change termination condition is determined based on the oil quality information, oil filling amount information, oil discharge amount information of the refrigeration system, or the running time of the oil change mode; if the refrigeration system meets the oil change termination condition, the first valve and the second valve are closed to exit the oil change mode.

[0029] In some embodiments, entering the oil change mode includes:

[0030] The duty ratio of the first valve and the duty ratio of the second valve are dynamically adjusted based on the oil filling amount information and the oil discharge amount information to balance the oil filling amount of the oil filling flow path and the oil discharge amount of the oil discharge flow path within an allowable range.

[0031] In some embodiments, dynamically adjusting the duty cycle of the first valve and the duty cycle of the second valve based on the oil filling amount information and the oil discharge amount information to balance the oil filling amount of the oil filling flow path and the oil discharge amount of the oil discharge flow path within an allowable range includes:

[0032] Determine the oil filling characteristic value based on the oil filling amount information, and determine the oil releasing characteristic value based on the oil releasing amount information; wherein the types of the oil filling characteristic value and the oil releasing characteristic value are both oil level change value, oil flow change value, or oil volume change value;

[0033] If the oil filling characteristic value is greater than the oil releasing characteristic value, and the difference between the two exceeds a first preset range, then reducing the duty cycle of the first valve;

[0034] If the oil release characteristic value is greater than the oil filling characteristic value, and the difference between the two exceeds the first preset range, the duty cycle of the second valve is reduced.

[0035] In some embodiments, if the refrigeration system meets the oil change end condition, closing the first valve and the second valve, and exiting the oil change mode includes:

[0036] If it is determined based on the oil quality information or the running time of the oil change mode that the refrigeration system meets the first oil change termination condition, the first valve and the second valve are closed synchronously or asynchronously based on the oil filling amount information and the oil discharge amount information until the first valve and the second valve are both closed, and the oil change mode is exited; the first oil change termination condition is used to indicate that the oil quality of the refrigeration system is qualified and / or the oil change mode has reached the set running time.

[0037] In some embodiments, based on the oil filling amount information and the oil draining amount information, the first valve and the second valve are synchronously or asynchronously closed until both the first valve and the second valve are closed, and the oil change mode is exited, including:

[0038] determining an oil filling characteristic value according to the oil filling amount information, determining an oil release characteristic value according to the oil release information fed back by the oil release monitor, and judging whether a difference between the oil filling characteristic value and the oil release characteristic value exceeds a second preset range;

[0039] If the second preset range is not exceeded, the first valve and the second valve are closed synchronously, and the oil change mode is exited;

[0040] If it exceeds the second preset range and the oil filling characteristic quantity is greater than the oil releasing characteristic quantity, the first valve is closed first; if it exceeds the second preset range and the oil releasing characteristic quantity is greater than the oil filling characteristic quantity, the second valve is closed first until both the first valve and the second valve are closed, and the oil change mode is exited.

[0041] In some embodiments, the oil filling amount information includes oil level information of the oil storage tank, and the oil discharge amount information includes oil level information of the oil collection tank;

[0042] If the refrigeration system meets the oil change end condition, closing the first valve and the second valve, and exiting the oil change mode, includes:

[0043] If it is determined based on the oil level information of the oil collecting tank or the oil level information of the oil storage tank that the refrigeration system meets the second oil change termination condition, the first valve and the second valve are closed synchronously to exit the oil change mode; the second oil change termination condition is used to indicate that the oil collecting tank has reached the oil collection upper limit and / or the oil storage tank has reached the oil storage lower limit.

[0044] In some embodiments, after exiting the oil change mode, the method further includes:

[0045] Open the oil drain valve of the oil collecting tank until the oil collected in the oil collecting tank reaches the lower limit threshold of oil collection; open the oil filling valve of the oil storage tank until the oil storage in the oil storage tank reaches the upper limit threshold of oil storage.

[0046] In a third aspect, the present application provides a test device, comprising a refrigeration system, a heater and a test terminal, wherein the refrigeration system and the heater are used together to adjust the temperature of the test terminal;

[0047] The refrigeration system is the refrigeration system described in any of the above embodiments, or the refrigeration system can execute the control method of the refrigeration system described in any of the above embodiments.

[0048] When the above-mentioned refrigeration system and its control method and testing equipment are actually used, after the refrigeration system is started, the first compressor works, and the refrigerant circulates in the first refrigeration circuit to cool. If it is necessary to change the oil of the first compressor, open the first valve and the second valve, and the refrigeration system enters the oil change mode, replenishes new oil to the first compressor through the oil filling flow path, and discharges the old oil remaining in the oil separator through the oil discharge flow path. At this time, the injection of new oil and the discharge of old oil are carried out simultaneously to achieve the oil change of the first compressor. Moreover, when changing the oil of the first compressor, there is no need to shut down the first compressor, and the first refrigeration module is still in a refrigerating working state, and the refrigerant can maintain the circulation volume in the first refrigeration circuit without the need to re-inject the refrigerant.

[0049] In this way, the first compressor can not only change the oil efficiently, but also there is no need to frequently start and stop the first refrigeration module during the oil change process, and there is no need to repeatedly inject refrigerant, which will not affect the normal refrigeration work of the first refrigeration module and can improve the working efficiency of the refrigeration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0051] Figure 1 Schematic diagram of a refrigeration system according to some embodiments.

[0052] Figure 2 Schematic diagrams of refrigeration systems of other embodiments.

[0053] Figure 3 Schematic diagram of a flow chart of a control method for a refrigeration system in some embodiments.

[0054] Figure 4 Schematic diagram of the flow of control methods for refrigeration systems in other embodiments.

[0055] The reference numerals in the specific implementation manner are as follows:

[0056] 100. Refrigeration system; 10. First refrigeration module; L1. First refrigeration circuit; 11. First compressor; 12. Oil separator; h. Oil return port; 13. Condensing heat exchanger; 14. First expansion valve; 15. Load evaporator; 16. Oil storage tank; y1. Oil outlet; q1. Air vent; y2. Oil filling port; 16a. Oil filling valve; 17. Oil collecting tank; y3. Oil inlet; q2. Air extraction port; y4. Oil discharge port; 17a. Oil discharge valve; 18. Sight glass; S1. Oil filling flow path; f1. First valve; S2. Oil discharge flow path; f2. Second valve; S3. Oil return flow path; f3. Third valve; 20. Second refrigeration module; L2. Second refrigeration circuit; 21. Second compressor; 22. Condenser; 23. Second expansion valve. DETAILED DESCRIPTION

[0057] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0058] In the description of the present application, it should be understood that terms such as “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships, if any, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0059] In addition, if present, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0060] In this application, unless otherwise clearly specified and limited, if any, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0061] In the present application, if it appears, unless otherwise clearly specified and limited, a first feature “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature “above”, “above” and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature “below”, “below” and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0062] It should be noted that, if present, when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0063] Aiming at the problem in the background technology that the oil changing efficiency of the compressor in the refrigeration system is low and affects the normal operation of the refrigeration system, a refrigeration system is firstly proposed.

[0064] Figure 1 FIG. 1 is a schematic diagram of a refrigeration system 100 according to some embodiments. Figure 1The refrigeration system 100 proposed in the embodiment of the present application includes a first refrigeration module 10, which includes a first compressor 11, an oil separator 12, a condensing heat exchanger 13, a first expansion valve 14 and a load evaporator 15, which are sequentially connected to form a first refrigeration loop L1, and an oil filling flow path S1 and a first valve f1, an oil discharge flow path S2 and a second valve f2. The oil filling flow path S1 is connected to the return air port of the first compressor 11, the first valve f1 is arranged on the oil filling flow path S1, and is used to control whether the oil filling flow path S1 replenishes new oil to the first compressor 11, the oil discharge flow path S2 is connected to the oil return port h of the oil separator 12, and the second valve f2 is arranged on the oil discharge flow path S2, and is used to control whether the oil discharge flow path S2 discharges the old oil flowing out through the oil return port h to the outside.

[0065] In the first refrigeration module 10, the first compressor 11, the oil separator 12, the condensing heat exchanger 13, the first expansion valve 14 and the load evaporator 15 are connected in sequence to form a first refrigeration circuit L1. The load evaporator 15 can be used directly or indirectly for heat exchange with the test terminal of the test equipment to adjust the temperature of the test terminal. When the first refrigeration module 10 is started, the high-temperature gaseous refrigerant generated by the first compressor 11 flows to the condensing heat exchanger 13 for cooling after passing through the oil separator 12 to obtain a medium-temperature liquid refrigerant. The medium-temperature liquid refrigerant is then cooled and reduced in pressure by the first expansion valve 14 to become a low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant absorbs external heat through the load evaporator 15 to become a low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant finally flows back to the first compressor 11. Under the action of the first compressor 11, it is converted into a high-temperature and high-pressure gaseous refrigerant output again, and the cycle continues.

[0066] The refrigerant carries lubricating oil when it is discharged from the first compressor 11. When it flows through the oil separator 12, the lubricating oil is separated from the refrigerant and remains in the oil separator 12. As the refrigerant circulates in the first refrigeration circuit L1, the deteriorated lubricating oil (herein referred to as used oil) can remain in the oil separator 12.

[0067] The oil filling flow path S1 is connected to the return air port of the first compressor 11, and is used to fill new oil (i.e., lubricating oil of qualified oil quality) into the first compressor 11. The first valve f1 is used to control the conduction of the oil filling flow path S1. The oil discharge flow path S2 is connected to the oil return port h of the oil separator 12. The old oil remaining in the oil separator 12 can flow to the oil discharge flow path S2 through the oil return port h. The second valve f2 is used to control the conduction of the oil discharge flow path S2 to control whether the oil discharge flow path S2 discharges the old oil to the outside.

[0068] In actual application, after starting the refrigeration system 100, the first compressor 11 works, and the refrigerant circulates in the first refrigeration circuit L1 to cool. If it is necessary to change the oil of the first compressor 11, open the first valve f1 and the second valve f2, and the refrigeration system 100 enters the oil change mode, replenishes new oil to the first compressor 11 through the oil filling flow path S1, and discharges the old oil remaining in the oil separator 12 through the oil discharge flow path S2. At this time, the injection of new oil and the discharge of old oil are carried out simultaneously to achieve the oil change of the first compressor 11. Moreover, when changing the oil of the first compressor 11, there is no need to shut down the first compressor 11, and the first refrigeration module 10 is still in a refrigerating working state, and the refrigerant can maintain the circulation amount in the first refrigeration circuit L1 without re-injecting the refrigerant.

[0069] In this way, the first compressor 11 can not only change the oil efficiently, but also does not need to frequently start and stop the first refrigeration module 10 during the oil change process, and does not need to repeatedly inject refrigerant, which will not affect the normal refrigeration work of the first refrigeration module 10 and can improve the working efficiency of the refrigeration system 100.

[0070] In some embodiments, please refer to Figure 1 , the refrigeration system 100 further includes an oil return flow path S3 and a third valve f3. The oil return port h of the oil separator 12 is connected to the return port of the first compressor 11 through the oil return flow path S3, and the third valve f3 is arranged on the oil return flow path S3. The refrigeration system 100 has an oil return mode and an oil change mode. The third valve f3 is used to open the oil return to the first compressor 11 in the oil return mode, and the first valve f1 and the second valve f2 are used to open in the oil change mode to change the oil of the first compressor 11.

[0071] When the refrigeration system 100 is in the oil change mode, it indicates that the oil of the first compressor 11 needs to be changed. When the refrigeration system 100 is in the oil return mode, it indicates that the oil of the first compressor 11 does not need to be changed, and the lubricating oil that has not deteriorated separated by the oil separator 12 needs to be returned to the first compressor 11 through the oil return flow path S3.

[0072] In actual application, after starting the refrigeration system 100, the first compressor 11 works, and the refrigerant circulates in the first refrigeration circuit L1 for refrigeration. When the lubricating oil has not deteriorated and there is no need to change the oil of the first compressor 11, since the refrigerant carries the lubricating oil and flows out of the first compressor 11, in order to ensure the content of the lubricating oil in the first compressor 11, the third valve f3 is opened to enter the oil return mode, and the lubricating oil retained in the oil separator 12 is returned to the first compressor 11 to replenish the oil. When the lubricating oil deteriorates and the first compressor 11 needs to be changed, the lubricating oil retained in the oil separator 12 is deteriorated oil, and the first valve f1 and the second valve f2 are opened to enter the oil change mode.

[0073] Understandably, in the oil change mode, the third valve f3 is closed. In the oil return mode, the first valve f1 and the second valve f2 are closed. The entry and exit of the oil return mode may be based on the start-up time of the refrigeration system 100. For example, the refrigeration system 100 enters the oil return mode every 10 minutes of operation in the normal working mode. The entry and exit of the oil return mode may also be based on the liquid level of the lubricating oil in the compressor, etc., and the oil return mode is entered when the lubricating oil is insufficient.

[0074] In this way, the lubricating oil can be added to the first compressor 11 both when the lubricating oil is deteriorated and when it is not deteriorated, so as to ensure the content of the lubricating oil in the first compressor 11, which is beneficial to the normal operation of the first compressor 11.

[0075] In some embodiments, please refer to Figure 1 The first refrigeration module 10 further includes an oil storage tank 16 and / or an oil collecting tank 17. The oil storage tank 16 is used to store new oil. The oil filling flow path S1 connects the oil outlet y1 of the oil storage tank 16 with the return air port of the first compressor 11. The oil storage tank 16 has an oil filling port y2 and an oil filling valve 16a for opening and closing the oil filling port y2. The oil collecting tank 17 is used to store old oil. The oil discharge flow path S2 connects the oil return port h of the oil separator 12 with the oil inlet y3 of the oil collecting tank 17. The oil collecting tank 17 has an oil discharge port y4 and an oil discharge valve 17a for opening and closing the oil discharge port y4.

[0076] The oil outlet y1 of the oil storage tank 16 is connected to the return air port of the first compressor 11 through the oil filling flow path S1. When the refrigeration system 100 enters the oil change mode, the first valve f1 is opened, and the new oil in the oil storage tank 16 flows to the first compressor 11 through the oil filling flow path S1, thereby replenishing the new oil to the first compressor 11. The configuration of the oil storage tank 16 allows the refrigeration system 100 to reserve a certain amount of new oil without frequent manual refueling, shortening the oil change time and improving the oil change efficiency.

[0077] The oil inlet y3 of the oil collecting tank 17 is connected to the oil return port h of the oil separator 12 through the oil drain path S2. When the refrigeration system 100 enters the oil change mode, the second valve f2 opens, and the old oil in the oil separator 12 flows to the oil collecting tank 17 through the oil drain path S2 and is stored in the oil collecting tank 17. The oil collecting tank 17 can recycle the old oil while the refrigeration system 100 is continuously running, thereby improving the oil change efficiency.

[0078] In further embodiments, see Figure 1 The oil storage tank 16 has an air vent q1 , which is located above the oil outlet y1 of the oil storage tank 16 and is connected to the return air port of the first compressor 11 .

[0079] The air vent q1 is in gas communication with the first compressor 11 , so that the air pressure in the oil storage tank 16 is balanced with the air pressure in the first compressor 11 , which helps the new oil in the oil storage tank 16 to flow smoothly into the first compressor 11 .

[0080] Specifically, the air vent q1 of the oil storage tank 16 may be arranged higher than the air return port of the first compressor 11 to prevent the lubricating oil entering from the air return port from flowing back to the oil storage tank 16 through the air vent q1 of the oil storage tank 16 under the action of gravity.

[0081] In further embodiments, see Figure 1 The oil collecting tank 17 has an air suction port q2, and the air suction port q2 is connected to the air return port of the first compressor 11.

[0082] Specifically, the air suction port q2 of the oil collecting tank 17 can be set higher than the oil discharge port y4 thereof. The air suction port q2 is connected to the return air port of the first compressor 11. Under the suction pressure of the first compressor 11, the old oil in the oil separator 12 can be accelerated to flow into the oil collecting tank 17 through the oil inlet y3, and the old oil recovery is smoother.

[0083] It is possible that the first refrigeration circuit L1 has a flow path connected between the load evaporator 15 and the return air port of the first compressor 11, and the oil filling flow path S1 can be connected to the return air port of the first compressor 11 through the flow path. The air extraction port q2 of the oil collecting tank 17 can be connected to the return air port of the first compressor 11 through the flow path, and the connection position between the air extraction port q2 of the oil collecting tank 17 and the flow path is closer to the load evaporator 15 than the connection position between the oil filling flow path S1 and the flow path.

[0084] In some embodiments, the first refrigeration module 10 further includes an oil filling monitor (not shown), which is used to obtain oil filling amount information representing the amount of new oil added to the first compressor 11 via the oil filling flow path S1; and / or, the first refrigeration module 10 further includes an oil discharge monitor (not shown), which is used to obtain oil discharge amount information representing the amount of old oil discharged to the outside via the oil discharge flow path S2.

[0085] The oil filling monitor may be a device for measuring and monitoring the oil flow rate, oil flow rate, etc. flowing through the oil filling flow path S1, or a device for measuring and monitoring the oil level and total amount of oil in the oil storage tank 16 connected to the oil filling flow path S1. That is, the oil filling amount information may be oil level information, oil flow information, oil flow rate information, total amount of oil information, etc., depending on the specific type of the oil filling monitor, as long as the oil filling amount information can directly or indirectly feedback the amount of new oil provided by the oil filling flow path S1 to the first compressor 11.

[0086] Similarly, the oil discharge monitor may be a device for measuring and monitoring the oil flow rate, oil flow rate, etc. flowing through the oil discharge flow path S2, or a device for measuring and monitoring the oil level, oil total amount, etc. in the oil collecting tank 17 connected to the oil discharge flow path S2. That is, the oil discharge amount information may be oil level information, oil flow information, oil flow rate information, oil total amount information, etc., depending on the specific type of the oil discharge monitor, as long as the oil discharge amount information can directly or indirectly feedback the amount of old oil discharged from the oil discharge flow path S2.

[0087] In actual application, the oil change process can be fed back according to the filling flow information obtained by the oil filling monitor and / or the oil discharge amount information obtained by the oil discharge monitor, which is used to control whether the oil change mode is ended. It can also be used to control the oil change process, for example, by comparing the filling flow information and the oil discharge amount information to control the duty cycle of the first valve f1 and the second valve f2, so that the amount of new oil added to the refrigeration system 100 and the amount of old oil discharged are balanced within the allowable range.

[0088] Specifically in the embodiment, the oil filling monitor includes an oil filling level meter (not shown) and / or an oil filling flow meter (not shown). The oil filling level meter is arranged on the oil storage tank 16 connected to the oil filling flow path S1, and the oil filling amount information includes the oil level information of the new oil in the oil storage tank 16 obtained by the oil filling level meter. The oil filling flow meter is arranged on the oil filling flow path S1, and the oil filling amount information includes the oil flow information of the new oil in the oil filling flow path S1 obtained by the oil filling flow meter.

[0089] Specifically, the oil level gauge can obtain the oil level information of the oil storage tank 16. According to the oil level information of the oil storage tank 16, the change in the volume of oil discharged from the oil storage tank 16 can be known. The change in the oil volume is the amount of new oil flowing through the oil filling flow path S1. That is, the oil level information of the oil storage tank 16 can indirectly feed back the amount of new oil supplemented to the first compressor 11 through the oil filling flow path S1.

[0090] Specifically, the oil filling flow meter can obtain the instantaneous flow or cumulative flow of the oil filling flow path S1, that is, the oil flow information includes the instantaneous oil flow information or the cumulative oil flow information, and the amount of new oil flowing through the oil filling flow path S1 in the oil change mode can be calculated according to the instantaneous flow and the cumulative flow, that is, the amount of new oil added to the first compressor 11 through the oil filling oil path is directly or indirectly fed back according to the oil flow information obtained by the oil filling flow meter. Those skilled in the art can select the oil filling flow meter and the oil filling level meter in a conventional manner, which is not limited here.

[0091] At this time, the oil filling amount information is obtained through the oil filling level meter and / or the oil filling flow meter, which is simple to configure and easy to implement.

[0092] Of course, in other embodiments, the oil filling monitor may also include an oil filling flowmeter arranged in the oil filling flow path S1, and the oil filling flowmeter is used to monitor the flow velocity of the new oil in the oil filling flow path S1. The oil filling flow rate can be converted according to the oil filling flow velocity and the oil filling time, and then the amount of new oil added to the oil filling flow path S1 can be indirectly fed back.

[0093] Specifically in the embodiment, the oil drain monitor includes an oil drain level meter (not shown) and / or an oil drain flow meter (not shown). The oil drain level meter is disposed on the oil collecting tank 17 connected to the oil drain flow path S2, and the oil drain amount information includes the oil level information of the old oil in the oil collecting tank 17 obtained by the oil drain level meter. The oil drain flow meter is disposed on the oil drain flow path S2, and the oil drain amount information includes the oil flow information of the old oil in the oil drain flow path S2 obtained by the oil drain flow meter.

[0094] Specifically, the oil drain level meter can obtain the oil level information of the oil collecting tank 17. According to the oil level information of the oil collecting tank 17, the change in the volume of oil collected in the oil collecting tank 17 can be known. The change in the oil volume is the amount of old oil discharged by the oil drain flow path S2. That is, according to the oil level information of the oil collecting tank 17, the amount of old oil discharged to the oil collecting tank 17 through the oil drain flow path S2 can be indirectly fed back.

[0095] Specifically, the oil drain flowmeter can obtain the instantaneous flow rate or the accumulated flow rate of the oil drain flow path S2, and the amount of old oil flowing through the oil drain flow path S2 in the oil change mode can be calculated according to the instantaneous flow rate and the accumulated flow rate, that is, the amount of old oil discharged to the oil collecting tank 17 through the oil drain path can be directly or indirectly fed back according to the oil flow information obtained by the oil drain flowmeter. Those skilled in the art can select the oil drain flowmeter and the oil drain level meter in a conventional manner, which is not limited here.

[0096] At this time, the oil discharge amount information is obtained through the oil discharge level meter and / or the oil discharge flow meter, which is simple to configure and easy to implement.

[0097] Of course, in other embodiments, the oil drain monitor may also include an oil drain flow meter arranged in the oil drain flow path S2, and the oil drain flow meter is used to monitor the flow velocity of the old oil in the oil drain flow path S2. The oil drain flow rate can be converted according to the oil drain flow velocity and the oil drain time, and then the amount of old oil discharged from the oil drain flow path S2 can be indirectly fed back.

[0098] In some embodiments, the first refrigeration module 10 further includes an oil quality monitor, which is used to monitor whether the quality of the oil separated by the oil separator 12 is qualified.

[0099] Specifically, the oil quality monitor may include an optical sensor, which obtains the light transmittance of the lubricating oil through the optical sensor to determine whether the quality of the lubricating oil is qualified. The worse the light transmittance of the lubricating oil, the worse its quality is generally. The oil quality monitor may also include a viscometer, which tests the viscosity of the lubricating oil through the viscometer to determine whether the oil quality is qualified. The higher the viscosity of the lubricating oil, the worse its quality is generally. The oil quality monitor may also include an acidity meter, which tests the pH of the lubricating oil through the acidity meter to determine whether the oil quality is qualified. The higher the acidity of the lubricating oil, the worse its quality is generally. The specific choice of the oil quality monitor is not limited here, and those skilled in the art can configure it according to the commonly used methods for determining whether the lubricating oil has deteriorated.

[0100] As the refrigeration system 100 operates, deteriorated lubricating oil is continuously retained in the oil separator 12. If the lubricating oil in the oil separator 12 is not deteriorated, the oil can be returned to the first compressor 11 through the oil return flow path S3 in the oil return mode. If the lubricating oil in the oil separator 12 is deteriorated, the old oil in the oil separator 12 can be discharged in the oil change mode, and new oil can be filled into the compressor to achieve oil change of the first compressor 11.

[0101] At this time, the quality of the lubricating oil can be directly monitored by the oil quality monitor to control whether the refrigeration system 100 enters the oil change mode, which can more accurately control the progress of the oil change and is more conducive to the healthy operation of the first compressor 11.

[0102] In one embodiment, the oil quality monitor is arranged on the flow path connected to the oil return port h of the oil separator 12, which makes it easier to install and maintain the oil quality monitor. Specifically, the oil quality monitor can be arranged on the oil return flow path S3 or on the oil discharge flow path S2. In one example, the oil return flow path S3 and the oil discharge flow path S2 are connected to the oil return port h through a transition flow path, and the oil quality monitor can be arranged on the transition flow path. Of course, in other embodiments, the oil quality monitor can be set in the oil separator 12.

[0103] In one embodiment, referring to Figure 1 The oil quality monitor includes a sight glass 18, which is used to display the color of the oil separated by the oil separation. When the lubricating oil deteriorates, its color is usually darker and more turbid. The staff can observe the color of the lubricating oil through the sight glass 18 and judge whether the lubricating oil is deteriorated based on experience. This method of distinguishing whether the lubricating oil is deteriorated is simple and economical. Of course, a camera device is also used to obtain a picture of the lubricating oil from the sight glass 18, and then judge whether the lubricating oil is deteriorated based on image analysis.

[0104] Figure 2 Schematic diagrams of refrigeration systems 100 according to other embodiments.

[0105] In some embodiments, reference Figure 2The refrigeration system 100 also includes a second refrigeration module 20, which includes a second compressor 21, a condenser 22, and a second expansion valve 23 that are sequentially connected to form a second refrigeration circuit L2. The condensing heat exchanger 13 heat exchanges the first refrigeration circuit L1 and the second refrigeration circuit L2, and is located between the second expansion valve 23 and the second compressor 21 on the second refrigeration circuit L2.

[0106] The first refrigeration module 10 and the second refrigeration module 20 exchange heat through the condensing heat exchanger 13, and the condensing heat exchanger 13 is located in the first refrigeration loop L1 and the second refrigeration loop L2. In the second refrigeration loop L2, the condensing heat exchanger 13 acts as an evaporator to cool the refrigerant in the first refrigeration loop L1, and is arranged between the second expansion valve 23 and the suction end of the second compressor 21.

[0107] At this time, the refrigeration system 100 is a cascade system, which uses the load evaporator 15 of the first refrigeration module 10 to cool the test terminal of the test equipment. The refrigeration system 100 has a strong refrigeration capacity and can provide a lower test temperature for the test terminal.

[0108] In addition, an embodiment of the present application further provides a control method for a refrigeration system 100 , which is applied to the refrigeration system 100 in any of the above embodiments. Figure 3 FIG. 1 is a flow chart of a control method of the refrigeration system 100 in some embodiments. Figure 3 The control method of the refrigeration system 100 provided in the embodiment of the present application includes:

[0109] S10, starting the refrigeration system 100;

[0110] When the refrigeration system 100 includes only the first refrigeration module 10, only the first compressor 11 can be started, and the first expansion valve 14 can be opened, so that the refrigerant circulates in the first refrigeration loop L1, and the first refrigeration module 10 refrigerates externally. When the refrigeration system 100 also includes the second refrigeration module 20, the second compressor 21 can be started, and the second expansion valve 23 can be opened, so that the refrigerant circulates in the second refrigeration loop L2, and the refrigerant in the first refrigeration loop L1 is condensed and cooled by the refrigerant in the second refrigeration loop L2 through the condensing heat exchanger 13.

[0111] S20, judging whether the refrigeration system 100 meets the oil change start condition based on the oil quality information of the refrigeration system 100 and / or the operation time of the refrigeration system 100; if the refrigeration system 100 meets the oil change start condition, opening the first valve f1 and the second valve f2 to enter the oil change mode;

[0112] The oil quality information of the refrigeration system 100 is obtained by the oil quality monitor. The oil quality monitor is used to obtain the oil quality information to determine whether the lubricating oil separated by the oil separator 12 is of qualified quality. For the introduction of the oil quality monitor, please refer to the above description. When the oil quality information indicates that the lubricating oil has deteriorated, it can be determined that the refrigeration system 100 meets the oil change start condition.

[0113] It is understandable that the longer the refrigeration system 100 runs, the longer its lubricating oil is used, and the greater the possibility of the lubricating oil deteriorating. The first time threshold can be set based on experience, and the running time of the refrigeration system 100 is compared with the first time threshold. When the running time of the refrigeration system 100 reaches the first time threshold, it is determined that the refrigeration system 100 meets the oil change start condition. Specifically, the running time of the refrigeration system 100 can be recorded by a timing device. After each oil change, the timing device is reset to zero and starts to record the running time of the refrigeration system 100 again.

[0114] The test equipment can generally provide low temperature test conditions and high temperature test conditions. Compared with the low temperature test condition, the lubricating oil flowing through the load evaporator 15 is more likely to deteriorate under the high temperature test condition because the load evaporator 15 is in a higher temperature test environment. In some examples, the operating time of the refrigeration system 100 can be the cumulative operating time of the refrigeration system 100 under the high temperature test condition.

[0115] S30, judging whether the refrigeration system 100 meets the oil change end condition based on the oil quality information, oil filling amount information, oil discharge amount information, or the running time of the oil change mode of the refrigeration system 100; if the refrigeration system 100 meets the oil change end condition, closing the first valve f1 and the second valve f2, and exiting the oil change mode.

[0116] As described above, the oil filling amount information can be obtained by the oil filling monitor. The oil filling amount information is used to directly or indirectly represent the amount of new oil added to the first compressor 11 through the oil filling flow path S1, which may include the oil level information of the oil storage tank 16 obtained by the oil filling level meter, the oil flow information of the oil filling flow path S1 obtained by the oil filling flow meter, and the oil flow rate information of the oil filling flow path S1 obtained by the oil filling flow rate meter.

[0117] As described above, the oil discharge amount information can be obtained by the oil discharge monitor. The oil discharge amount information is used to directly or indirectly characterize the amount of old oil discharged through the oil discharge flow path S2, which may include the oil level information of the oil collecting tank 17 obtained by the oil discharge level meter, the oil flow information of the oil discharge flow path S2 obtained by the oil discharge flow meter, and the oil flow rate information of the oil discharge flow path S2 obtained by the oil discharge flow rate meter.

[0118] After entering the oil change mode, it can be determined whether the refrigeration system 100 meets the oil change termination condition according to any one of the oil quality information, the oil filling amount information, the oil discharge amount information, and the operation time of the oil change mode. Specifically, if it is known from the oil quality information that the lubricating oil separated by the oil separator 12 is of qualified quality, it means that the first compressor 11 has been completely changed in oil and the oil change termination condition is met. If it is known from the oil filling amount information that the new oil added to the first compressor 11 by the oil filling flow path S1 has reached the set oil amount, or it is known from the oil discharge amount information that the old oil discharged to the outside by the oil discharge flow path S2 has reached the set oil amount, it means that the first compressor 11 has been completely changed in oil and the oil change termination condition is met. If the operation time of the oil change mode reaches the second time threshold (set according to experience), it means that the first compressor 11 has been completely changed in oil and the oil change termination condition is met. When the refrigeration system 100 meets the oil change termination condition, the first valve f1 and the second valve f2 are closed to exit the oil change mode.

[0119] At this time, the timing of the refrigeration system 100 entering and exiting the oil change mode can be determined based on the oil quality information, operating time, oil filling amount information, oil discharge amount information, etc. of the refrigeration system 100. When entering and exiting the oil change mode, the refrigeration system 100 is in a normal operating state. In this way, while changing the oil of the first compressor 11, there is no need to frequently start and stop the refrigeration system 100, which not only has a high oil change efficiency, but also helps to improve the working efficiency of the refrigeration system 100.

[0120] In some embodiments, in step S20, entering the oil change mode includes:

[0121] S21 . Dynamically adjust the duty ratio of the first valve f1 and the duty ratio of the second valve f2 based on the oil filling amount information and the oil discharge amount information to balance the oil filling amount of the oil filling flow path S1 and the oil discharge amount of the oil discharge flow path S2 within an allowable range.

[0122] In the oil change mode, after opening the first valve f1 and the second valve f2, the oil filling amount information and the oil discharge amount information are compared so that the amount of new oil added to the first compressor 11 by the oil filling flow path S1 (i.e. the oil filling amount) and the amount of old oil discharged by the oil discharge flow path S2 (i.e. the oil discharge amount) are balanced within the allowable range, thereby ensuring that the total amount of lubricating oil in the first refrigeration circuit L1 remains relatively constant, ensuring the stability of the system operation, and reducing the risk of damage to the first compressor 11.

[0123] Specifically, if the comparison between the filling amount information and the oil discharge amount information shows that the filling amount of the oil filling flow path S1 is too large compared to the oil discharge amount of the oil discharge flow path S2, the duty ratio of the first valve f1 can be reduced, that is, the opening frequency of the first valve f1 can be shortened to reduce the filling amount of the oil filling flow path S1. If the comparison between the filling amount information and the oil discharge amount information shows that the oil discharge amount of the oil discharge flow path S2 is too large compared to the filling amount of the oil filling flow path S1, the duty ratio of the second valve f2 can be reduced, that is, the opening frequency of the second valve f2 can be shortened to reduce the oil discharge amount of the oil discharge flow path S2.

[0124] For example, the filling amount information is the oil flow information of the filling flow path S1 obtained by the filling flow meter. The draining amount information is the oil flow information of the draining flow path S2 obtained by the draining flow meter. When the oil flow in the oil flow information of the filling flow path S1 is greater than the oil flow in the oil flow information of the draining flow path S2, it means that the filling amount of the filling flow path S1 is greater than the draining amount of the draining flow path S2, and the duty cycle of the first valve f1 is reduced. On the contrary, when the oil flow in the oil flow information of the filling flow path S1 is less than the oil flow in the oil flow information of the draining flow path S2, it means that the draining amount of the draining flow path S2 is greater than the filling amount of the filling flow path S1, and the duty cycle of the second valve f2 is reduced.

[0125] As another example, the oil filling amount information is the oil level information of the oil storage tank 16 obtained by the oil filling level meter. The oil discharge amount information is the oil level information of the oil discharge flow path S2 obtained by the oil discharge flow meter. The oil level change information of the liquid storage tank and the oil collecting tank 17 can be determined according to the oil level information and the preset initial level information. When the oil volume contained in the same liquid level of the liquid storage tank and the oil collecting tank 17 is the same, the size of the oil filling amount and the oil discharge amount can be judged by comparing the size of the oil level change value of the liquid storage tank and the oil collecting tank 17, and then the duty ratio of the first valve f1 and the second valve f2 can be adjusted. When the oil volume contained in the same liquid level of the liquid storage tank and the oil collecting tank 17 is different, the respective oil volume changes can be determined according to the oil level change information of the two and the set unit volume capacity, and the size of the oil filling amount and the oil discharge amount can be further judged according to the size of the oil volume change of the oil storage tank 16 and the oil volume change of the oil collecting tank 17, and then the duty ratio of the first valve f1 and the second valve f2 can be adjusted.

[0126] In some embodiments, step S21 of dynamically adjusting the duty ratio of the first valve f1 and the duty ratio of the second valve f2 based on the oil filling amount information and the oil discharge amount information to balance the oil filling amount of the oil filling flow path S1 and the oil discharge amount of the oil discharge flow path S2 within an allowable range includes:

[0127] S211. Determine the oil filling characteristic quantity based on the oil filling amount information, and determine the oil releasing characteristic quantity based on the oil releasing amount information; wherein the oil filling characteristic quantity and the oil releasing characteristic quantity are of the same type, and are both oil level change quantity, oil flow change quantity, or oil volume change quantity.

[0128] Specifically, if the oil filling monitor is an oil filling level gauge, and the oil draining monitor is an oil draining level gauge, then it can be determined based on the oil filling amount information and the oil draining amount information that both the oil filling characteristic amount and the oil draining characteristic amount are oil level change amounts. That is, the oil filling characteristic amount is used to indicate the amount of decrease in the oil level of the lubricating oil in the oil storage tank 16 after entering the oil change mode; the oil draining characteristic amount is used to indicate the amount of increase in the oil level of the lubricating oil in the oil collecting tank 17 after entering the oil change mode. When the types of the oil filling amount characteristic and the oil draining amount characteristic are oil level change amounts, it is usually required that the oil volume change amounts corresponding to the same level change amounts of the oil storage tank 16 and the oil collecting tank 17 are the same, for example, the amount of oil reduction corresponding to each 1 cm drop in the liquid level of the oil storage tank 16 is equal to the amount of oil increase corresponding to each 1 cm rise in the liquid level of the oil collecting tank 17.

[0129] Specifically, if the oil filling monitor is an oil filling flowmeter, and the oil draining monitor is an oil draining flowmeter, then it can be determined that the types of the oil filling characteristic quantity and the oil draining characteristic quantity are both oil flow change quantities based on the oil filling amount information and the oil draining amount information. That is, the oil filling characteristic quantity is used to indicate the flow change quantity of the lubricating oil flowing through the oil filling flow path S1 after entering the oil change mode; the oil draining characteristic quantity is used to indicate the flow change quantity of the lubricating oil flowing through the oil draining flow path S2 after entering the oil change mode. When both the oil filling flowmeter and the oil draining flowmeter are cumulative flowmeters, the corresponding flow change quantity is the cumulative flow change quantity. When both the oil filling flowmeter and the oil draining flowmeter are instantaneous flowmeters, the corresponding flow change quantity is the instantaneous flow change quantity.

[0130] Specifically, if the oil filling characteristic quantity and the oil releasing characteristic quantity are both oil volume change quantities, the oil volume change quantity can be converted based on the oil level change quantity and the oil flow rate change quantity.

[0131] If the oil filling amount information includes the oil level information of the oil storage tank 16, the oil level change of the oil storage tank 16 can be determined according to the oil level information of the oil storage tank 16, and then the oil volume reduction of the lubricating oil in the oil storage tank 16 can be determined according to the product of the tank volume size of the oil storage tank 16 corresponding to the unit level and the oil level change of the oil storage tank 16, and it is used as the oil volume change corresponding to the oil filling characteristic. Similarly, if the oil discharge amount information includes the oil level information of the oil collecting tank 17, the oil level change of the oil collecting tank 17 can be determined according to the oil level information of the oil collecting tank 17, and then the oil volume increase of the lubricating oil in the oil collecting tank 17 can be determined according to the product of the tank volume size of the oil collecting tank 17 corresponding to the unit level and the oil level change of the oil collecting tank 17, and it is used as the oil volume change corresponding to the oil discharge characteristic.

[0132] If the filling amount information includes the oil flow rate information of the filling flow path S1, the oil flow rate change of the filling flow path S1 can be determined according to the oil flow rate information of the filling flow path S1, and then the total amount of oil flowing through the filling flow path S1 can be determined according to the oil flow rate change of the filling flow path S1 and the operation time of the oil change mode, and the total amount of oil flowing through the filling flow path S1 can be used as the oil volume change corresponding to the filling characteristic amount. If the draining amount information includes the oil flow rate information of the draining flow path S2, the oil flow rate change of the draining flow path S2 can be determined according to the oil flow rate information of the draining flow path S2, and then the total amount of oil flowing through the draining flow path S2 can be determined according to the oil change of the draining flow path S2 and the operation time of the oil change mode, and the total amount of oil flowing through the draining flow path S2 can be used as the oil volume change corresponding to the filling characteristic amount.

[0133] S212, if the oil filling characteristic value is greater than the oil releasing characteristic value, and the difference between the two exceeds a first preset range, then reducing the duty cycle of the first valve f1;

[0134] S213: If the oil-releasing characteristic value is greater than the oil-filling characteristic value, and the difference between the two exceeds the first preset range, then the duty cycle of the second valve f2 is reduced.

[0135] When the oil filling characteristic quantity is greater than the oil discharge characteristic quantity, and the difference between the two exceeds the first preset range, it means that the oil filling speed of the refrigeration system 100 is greater than the oil discharge speed, and the difference between the two is not within the allowed range, which is not conducive to maintaining the balance between filling and discharge, and the duty cycle of the first valve f1 needs to be reduced. When the oil discharge characteristic quantity is greater than the oil filling characteristic quantity, and the difference between the two exceeds the first preset range, it means that the oil discharge speed of the refrigeration system 100 is greater than the oil filling speed, and the difference between the two is not within the allowed range, which is not conducive to maintaining the balance between filling and discharge, and the duty cycle of the second valve f2 is reduced. It can be understood that when the difference between the oil filling characteristic quantity and the oil discharge characteristic quantity does not exceed the first preset range, that is, the difference between the two is within the allowed range, there is no need to adjust the duty cycle of the first valve f1 and the second valve f2 to simplify the control.

[0136] For example, the oil filling characteristic corresponds to the oil volume change ΔA (a positive value), and the oil discharge characteristic corresponds to the oil volume change ΔB (a positive value). If ΔA>ΔB and |ΔA-ΔB|>ΔC, where ΔC is a set value, it means that the oil filling speed of the refrigeration system 100 is greater than the oil discharge speed, and the duty cycle of the first valve f1 needs to be reduced. On the contrary, if ΔB>ΔA and |ΔA-ΔB|>ΔC, it means that the oil discharge speed of the refrigeration system 100 is greater than the oil filling speed, and the duty cycle of the second valve f2 needs to be reduced.

[0137] It can be understood that the opening of the first valve f1 and the second valve f2 is controlled based on the pulse width modulation signal, and the flow rates of the first valve f1 and the second valve f2 can be changed by changing the duty ratio of the first valve f1 and the second valve f2.

[0138] In this embodiment, the adjustment of the first valve f1 and the second valve f2 is determined based on the comparison of the same type of oil filling characteristic quantity and oil releasing characteristic quantity, and the comparison of the difference between the two and the first preset range, which can simplify the control program, reduce the adjustment frequency of the first valve f1 and the second valve f2, and reduce system oscillation.

[0139] In some embodiments, in step S30, if the refrigeration system 100 meets the oil change end condition, the first valve f1 and the second valve f2 are closed to exit the oil change mode, including:

[0140] S31. If it is determined based on the oil quality information or the running time of the oil change mode that the refrigeration system 100 meets the first oil change termination condition, the first valve f1 and the second valve f2 are closed synchronously or asynchronously based on the oil filling amount information and the oil discharge amount information until both the first valve f1 and the second valve f2 are closed, and the oil change mode is exited; the first oil change termination condition is used to indicate that the oil quality of the refrigeration system 100 is qualified and / or the oil change mode has reached the set running time.

[0141] In this embodiment, the oil change end condition includes a first oil change end condition. When the refrigeration system 100 meets the first oil change end condition, it means that the refrigeration system 100 meets any one of the conditions of qualified oil quality and the oil change mode reaching the set time, and the refrigeration system 100 has completed the oil change.

[0142] Specifically, as described above, the oil quality information fed back by the oil quality monitor can be used to determine whether the oil quality of the refrigeration system 100 is qualified, for example, by observing the color of the lubricating oil separated by the oil separator 12 through the sight glass 18, or by taking other methods mentioned above, which will not be described in detail here.

[0143] The set running time can be determined based on experience or after multiple tests. After the refrigeration system 100 runs in the oil change mode for the set time, the oil quality can meet the requirements.

[0144] When the refrigeration system 100 meets the first oil change end condition, the first valve f1 and the second valve f2 are closed synchronously or asynchronously based on the oil filling amount information and the oil discharge amount information. That is, the first valve f1 and the second valve f2 can be closed synchronously, or the first valve f1 and the second valve f2 can be closed one by one according to the size of the oil filling speed and the oil discharge speed, so that after the oil change is completed, the oil filling amount and the oil discharge amount of the refrigeration system 100 can be balanced within the allowable range.

[0145] Specifically in the embodiment, step S31 includes:

[0146] S311, determining an oil filling characteristic value according to the oil filling amount information, determining an oil release characteristic value according to the oil release information fed back by the oil release monitor, and judging whether a difference between the oil filling characteristic value and the oil release characteristic value exceeds a second preset range;

[0147] The description of the oil filling characteristic value and the oil draining characteristic value can be referred to above, and will not be repeated here. The first preset range and the second preset range can be set to be the same or different.

[0148] S312, if it does not exceed the second preset range, the first valve f1 and the second valve f2 are closed synchronously, and the oil change mode is exited;

[0149] If the difference between the oil filling characteristic value and the oil discharge characteristic value exceeds the second preset range, it means that the oil filling amount and the oil discharge amount of the refrigeration system 100 maintain a balance within the allowable range, then the first valve f1 and the second valve f2 can be closed at the same time to exit the oil change mode.

[0150] For example, the oil filling characteristic corresponds to the oil volume change ΔA (a positive value), and the oil draining characteristic corresponds to the oil volume change ΔB (a positive value). When |ΔA-ΔB|≤ΔD, where ΔD is the set value, the first valve f1 and the second valve f2 are closed at the same time to exit the oil change mode.

[0151] S313. If it exceeds the second preset range and the oil filling characteristic quantity is greater than the oil draining characteristic quantity, the first valve f1 is closed first; if it exceeds the second preset range and the oil draining characteristic quantity is greater than the oil filling characteristic quantity, the second valve f2 is closed first until both the first valve f1 and the second valve f2 are closed, and the oil change mode is exited.

[0152] If the difference between the oil filling characteristic value and the oil discharge characteristic value does not exceed the second preset range, it means that the oil filling amount and the oil discharge amount of the refrigeration system 100 are not balanced within the allowable range, and the first valve f1 and the second valve f2 are closed in sequence according to the sizes of the two.

[0153] For example, if ΔA>ΔB and |ΔA-ΔB|>ΔD, it means that the oil filling amount is greater than the oil discharge amount, and there is no need to continue filling the oil. In this case, the first valve f1 is closed first, and after |ΔA-ΔB|≤ΔD, the second valve f2 is closed.

[0154] On the contrary, if ΔB>ΔA and |ΔA-ΔB|>ΔD, it means that the amount of oil discharged is greater than the amount of oil charged, and there is no need to continue draining the oil. In this case, the second valve f2 is closed first, and after |ΔA-ΔB|≤ΔD, the first valve f1 is closed.

[0155] In this embodiment, before exiting the oil change mode, it can be determined that the oil filling and oil discharge amounts of the refrigeration system 100 remain balanced within the allowable range, further ensuring that the total amount of lubricating oil in the first refrigeration circuit L1 remains relatively constant, ensuring the stability of the system operation, and reducing the risk of damage to the first compressor 11.

[0156] In some embodiments, the oil filling amount information includes the oil level information of the oil storage tank 16, and the oil discharge amount information includes the oil level information of the oil collecting tank 17. If the refrigeration system 100 meets the oil change end condition, the first valve f1 and the second valve f2 are closed, and the oil change mode is exited, including:

[0157] S32. If it is determined based on the oil level information of the oil collecting tank 17 or the oil level information of the oil storage tank 16 that the refrigeration system 100 meets the second oil change termination condition, the first valve f1 and the second valve f2 are synchronously closed to exit the oil change mode; the second oil change termination condition is used to indicate that the oil collecting tank 17 has reached the upper limit of oil collection and / or the oil storage tank 16 has reached the lower limit of oil storage.

[0158] That is, the oil filling amount information is obtained by the oil filling level gauge provided in the liquid storage tank, and the oil discharge amount information is obtained by the oil discharge level gauge provided in the oil collecting tank 17 .

[0159] When the oil level information of the oil collecting tank 17 indicates that the liquid level in the oil collecting tank 17 has reached the upper limit of the oil collection, that is, the lubricating oil in the oil collecting tank 17 is full, if the refrigeration system 100 continues to change the oil, there is a risk of oil leakage in the oil collecting tank 17 or the return oil port h cannot continue to discharge the old oil, resulting in the new oil and the old oil mixing in the oil separator 12. At this time, the refrigeration system 100 meets the second oil change end condition and needs to end the oil change, then the first valve f1 and the second valve f2 are closed synchronously to directly exit the oil change mode.

[0160] When the oil level information of the oil storage tank 16 indicates that the liquid level in the oil storage tank 16 reaches the lower limit of the oil storage, there is no oil in the oil storage tank 16 and no new oil can be provided. If the refrigeration system 100 continues to change the oil, there is no new oil to be filled, which destroys the balance of oil filling and oil discharge in the refrigeration system 100. The first compressor 11 is short of oil. At this time, the refrigeration system 100 meets the second oil change end condition and needs to end the oil change. Then, the first valve f1 and the second valve f2 are closed synchronously to directly exit the oil change mode.

[0161] In this way, when there is no oil in the oil storage tank 16 or the oil collecting tank 17 is full of oil, the refrigeration system 100 can directly exit the oil change mode, to avoid the situation where there is too little or too little lubricating oil in the refrigeration system 100, the first compressor 11 is short of oil or the oil quality is unqualified, etc., and the refrigeration system 100 is in an abnormal oil change state, affecting the normal oil change of the refrigeration system 100.

[0162] Understandably, when the refrigeration system 100 preferentially satisfies the first oil change end condition, step S31 is executed to exit the oil change mode according to step S31. When the refrigeration system 100 preferentially satisfies the second oil change end condition, step S32 is executed to exit the oil change mode according to step S32.

[0163] Figure 4 is a flow chart of a control method of a refrigeration system 100 in some other embodiments, and Figure 3 Compared with the embodiment shown in the figure, the difference is that after the step of exiting the oil change mode, it also includes:

[0164] S40, open the oil discharge valve 17a of the oil collecting tank 17 until the oil collected in the oil collecting tank 17 reaches the lower limit threshold of the oil collected; open the oil filling valve 16a of the oil storage tank 16 until the oil storage in the oil storage tank 16 reaches the upper limit threshold of the oil storage.

[0165] After exiting the oil change mode, the old oil collected in the oil collecting tank 17 is drained so that the old oil can be collected again next time. Specifically, the oil drain valve 17a of the oil collecting tank 17 is opened, and the oil level information of the oil collecting tank 17 fed back by the oil drain level gauge on the oil collecting tank 17 is compared with the lower limit threshold of the oil collecting tank 17. When the oil level information of the oil collecting tank 17 reaches the lower limit threshold of the oil collecting tank 17, it indicates that the oil collecting tank 17 has completed draining.

[0166] After exiting the oil change mode, new lubricating oil is added to the oil tank 16 to facilitate the next refilling. Specifically, the oil filling valve 16a of the oil tank 16 is opened, and the oil level information of the oil tank 16 fed back by the oil filling level gauge on the oil tank 16 is compared with the upper limit threshold of the oil tank 16. When the oil level information of the oil tank 16 reaches the upper limit threshold of the oil tank 16, it indicates that the oil filling of the oil tank 16 is completed.

[0167] The draining of the oil collecting tank 17 and the refueling of the oil storage tank 16 can be performed synchronously or asynchronously. As long as the oil collection amount of the oil collecting tank 17 reaches the lower limit of the oil collection and the oil storage amount of the oil storage tank 16 reaches the upper limit of the oil storage before the oil change mode is entered next time, the normal operation of the oil change mode can be ensured.

[0168] In addition, an embodiment of the present application also provides a testing device, including a refrigeration system, a heater and a test terminal, the refrigeration system and the heater are used together to adjust the temperature of the test terminal, the refrigeration system is the refrigeration system 100 of the above embodiment, or the refrigeration system can execute the control method of the refrigeration system 100 in the above embodiment.

[0169] The testing device has all the beneficial effects of the above embodiments.

[0170] Among them, the test equipment can be a sorting test equipment, a probe station equipment, an aging test equipment, a packaging test equipment, etc., which are used for performance testing of semiconductor devices such as chips or wafers. The test terminal can be a test pressure head, a test cavity, a preheating plate, a material shuttle, a wafer carrier plate, etc. The test cavity is a cavity structure for providing a test space, and a plurality of chips or wafers can be stored in the test space. The load evaporator 15 of the refrigeration system 100 can be arranged in the test space to adjust the test temperature of the test space. The test pressure head refers to a pressure head structure that can press down and abut on the chip, which is in direct contact with the chip to regulate the temperature of the chip. A refrigerant flow path can be set in the load evaporator 15 of the refrigeration system 100, and the refrigerant in the refrigerant flow path is cooled by the refrigerant flowing through the load evaporator 15. The refrigerant flow path can be connected to the pipeline in the test pressure head, and the temperature of the test pressure head is adjusted by the refrigerant. The preheating plate refers to a structure that carries the chip and adjusts the temperature of the chip. The refrigerant flow path can be connected to the pipeline of the preheating plate, and the temperature of the preheating plate is adjusted by the refrigerant. The shuttle refers to a structure for transporting chips. The coolant flow path can be connected to the pipeline in the shuttle, and the temperature of the shuttle is adjusted by the coolant. The wafer carrier refers to a structure for carrying wafers by adsorption. The coolant flow path can be connected to the pipeline in the wafer carrier, and the test temperature of the wafer is adjusted by the coolant. The heater can be directly set at each test terminal and cooperate with the refrigeration system 100 to achieve precise adjustment of the temperature of the test terminal.

[0171] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0172] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A refrigeration system, characterized in that: include: The first refrigeration module (10) comprises: A first compressor (11), an oil separator (12), a condensing heat exchanger (13), a first expansion valve (14) and a load evaporator (15) are sequentially connected to form a first refrigeration circuit (L1); and an oil filling flow path (S1) and a first valve (f1), the oil filling flow path (S1) being connected to an air return port of the first compressor (11), the first valve (f1) being arranged on the oil filling flow path (S1) and being used to control whether the oil filling flow path (S1) replenishes new oil to the first compressor (11); An oil drain flow path (S2) and a second valve (f2), wherein the oil drain flow path (S2) is connected to an oil return port (h) of the oil separator (12), and the second valve (f2) is arranged on the oil drain flow path (S2) and is used to control whether the oil drain flow path (S2) discharges the old oil flowing out through the oil return port (h) to the outside.

2. The refrigeration system according to claim 1, characterized in that: The refrigeration system further comprises an oil return flow path (S3) and a third valve (f3), the oil return port (h) of the oil separator (12) is connected to the air return port of the first compressor (11) via the oil return flow path (S3), and the third valve (f3) is arranged on the oil return flow path (S3); The refrigeration system has an oil return mode and an oil change mode. The third valve (f3) is used to open in the oil return mode to return oil to the first compressor (11); the first valve (f1) and the second valve (f2) are used to open in the oil change mode to change oil for the first compressor (11).

3. The refrigeration system according to claim 1, characterized in that: The first refrigeration module (10) further comprises an oil storage tank (16) and / or an oil collecting tank (17); The oil storage tank (16) is used to store new oil, and the oil filling flow path (S1) connects the oil outlet (y1) of the oil storage tank (16) and the air return port of the first compressor (11); the oil storage tank (16) has an oil filling port (y2) and an oil filling valve (16a) for opening and closing the oil filling port (y2); The oil collecting tank (17) is used to store old oil, the oil drain path (S2) connects the oil return port (h) of the oil separator (12) and the oil inlet (y3) of the oil collecting tank (17), and the oil collecting tank (17) has an oil drain port (y4) and an oil drain valve (17a) for opening and closing the oil drain port (y4).

4. The refrigeration system according to claim 3, characterized in that: The oil storage tank (16) has a vent (q1), the vent (q1) is located above the oil outlet (y1) of the oil storage tank (16) and is connected to the air return port of the first compressor (11); The oil collecting tank (17) has an air extraction port (q2) and is connected to an air return port of the first compressor (11).

5. The refrigeration system according to any one of claims 1 to 4, characterized in that: The first refrigeration module (10) further comprises an oil filling monitor, the oil filling monitor being used to obtain oil filling amount information representing the amount of new oil added to the first compressor (11) via the oil filling flow path (S1); and / or, The first refrigeration module (10) further comprises an oil drain monitor, which is used to obtain oil drain quantity information representing the quantity of old oil discharged to the outside through the oil drain flow path (S2).

6. The refrigeration system according to claim 5, characterized in that: The oil filling monitor comprises an oil filling level meter and / or an oil filling flow meter; the oil filling level meter is arranged on an oil storage tank (16) connected to the oil filling flow path (S1), and the oil filling amount information comprises oil level information of new oil in the oil storage tank (16) obtained by the oil filling level meter; the oil filling flow meter is arranged on the oil filling flow path (S1), and the oil filling amount information comprises oil flow information of new oil in the oil filling flow path (S1) obtained by the oil filling flow meter; The oil drain monitor comprises an oil drain level meter and / or an oil drain flow meter; the oil drain level meter is arranged on an oil collecting tank (17) connected to the oil drain flow path (S2), and the oil drain quantity information comprises oil level information of the old oil in the oil collecting tank (17) obtained by the oil drain level meter; the oil drain flow meter is arranged on the oil drain flow path (S2), and the oil drain quantity information comprises oil flow information of the old oil in the oil drain flow path (S2) obtained by the oil drain flow meter.

7. The refrigeration system according to any one of claims 1 to 4, characterized in that: The first refrigeration module (10) further comprises an oil quality monitor, which is used to monitor whether the quality of the oil separated by the oil separator (12) is qualified; The oil quality monitor is arranged on a flow path connected to the oil return port (h) of the oil separator (12).

8. The refrigeration system according to claim 7, characterized in that: The oil quality monitor comprises a sight glass (18), and the sight glass (18) is used to display the color of the oil separated by the oil separator (12).

9. The refrigeration system according to any one of claims 1 to 4, characterized in that: The refrigeration system further comprises a second refrigeration module (20), the second refrigeration module (20) comprising a second compressor (21), a condenser (22) and a second expansion valve (23) which are sequentially connected to form a second refrigeration circuit (L2), the condensing heat exchanger (13) heat-exchanging the first refrigeration circuit (L1) and the second refrigeration circuit (L2), and being located between the second expansion valve (23) and the second compressor (21) on the second refrigeration circuit (L2).

10. A control method for a refrigeration system, applied to the refrigeration system according to any one of claims 1 to 9, characterized in that: The control method comprises: Start the refrigeration system; determining whether the refrigeration system meets the oil change start condition based on the oil quality information of the refrigeration system and / or the operation time of the refrigeration system; if the refrigeration system meets the oil change start condition, opening the first valve (f1) and the second valve (f2) to enter the oil change mode; Based on the oil quality information, oil filling amount information, oil draining amount information of the refrigeration system or the running time of the oil change mode, it is judged whether the refrigeration system meets the oil change end condition; if the refrigeration system meets the oil change end condition, the first valve (f1) and the second valve (f2) are closed to exit the oil change mode.

11. The control method of a refrigeration system according to claim 10, characterized in that: The step of entering the oil change mode includes: The duty ratio of the first valve (f1) and the duty ratio of the second valve (f2) are dynamically adjusted based on the oil filling amount information and the oil discharge amount information to balance the oil filling amount of the oil filling flow path (S1) and the oil discharge amount of the oil discharge flow path (S2) within an allowable range.

12. The control method of the refrigeration system according to claim 11, characterized in that: Dynamically adjusting the duty cycle of the first valve (f1) and the duty cycle of the second valve (f2) based on the oil filling amount information and the oil discharge amount information to balance the oil filling amount of the oil filling flow path (S1) and the oil discharge amount of the oil discharge flow path (S2) within an allowable range, comprising: Determine the oil filling characteristic value based on the oil filling amount information, and determine the oil releasing characteristic value based on the oil releasing amount information; wherein the types of the oil filling characteristic value and the oil releasing characteristic value are both oil level change value, oil flow change value, or oil volume change value; If the oil filling characteristic value is greater than the oil releasing characteristic value, and the difference between the two exceeds a first preset range, then reducing the duty cycle of the first valve (f1); If the oil release characteristic value is greater than the oil filling characteristic value, and the difference between the two exceeds the first preset range, the duty cycle of the second valve (f2) is reduced.

13. The control method of a refrigeration system according to claim 10, characterized in that: If the refrigeration system meets the oil change end condition, the first valve (f1) and the second valve (f2) are closed, and the oil change mode is exited, including: If it is determined based on the oil quality information or the running time of the oil change mode that the refrigeration system meets the first oil change termination condition, the first valve (f1) and the second valve (f2) are closed synchronously or asynchronously based on the oil filling amount information and the oil discharge amount information until the first valve (f1) and the second valve (f2) are both closed, and the oil change mode is exited; the first oil change termination condition is used to indicate that the oil quality of the refrigeration system is qualified or the oil change mode has reached a set running time.

14. The control method of the refrigeration system according to claim 13, characterized in that: Synchronously or asynchronously closing the first valve (f1) and the second valve (f2) based on the oil filling amount information and the oil discharge amount information until the first valve (f1) and the second valve (f2) are both closed, and exiting the oil change mode, includes: determining an oil filling characteristic value according to the oil filling amount information, determining an oil release characteristic value according to the oil release information fed back by the oil release monitor, and judging whether a difference between the oil filling characteristic value and the oil release characteristic value exceeds a second preset range; If the oil pressure does not exceed the second preset range, the first valve (f1) and the second valve (f2) are closed synchronously, and the oil change mode is exited; If it exceeds the second preset range and the oil filling characteristic quantity is greater than the oil draining characteristic quantity, the first valve (f1) is closed first; if it exceeds the second preset range and the oil draining characteristic quantity is greater than the oil filling characteristic quantity, the second valve (f2) is closed first, until both the first valve (f1) and the second valve (f2) are closed, and the oil change mode is exited.

15. The control method of a refrigeration system according to claim 10, characterized in that: The oil filling amount information includes oil level information of the oil storage tank (16), and the oil discharge amount information includes oil level information of the oil collecting tank (17); If the refrigeration system meets the oil change end condition, the first valve (f1) and the second valve (f2) are closed, and the oil change mode is exited, including: If it is determined based on the oil level information of the oil collecting tank (17) or the oil level information of the oil storage tank (16) that the refrigeration system meets the second oil change termination condition, the first valve (f1) and the second valve (f2) are closed synchronously to exit the oil change mode; the second oil change termination condition is used to indicate that the oil collecting tank (17) has reached the upper limit of oil collection and / or the oil storage tank (16) has reached the lower limit of oil storage.

16. The control method of a refrigeration system according to claim 10, characterized in that: After exiting the oil change mode, the method further includes: The oil discharge valve (17a) of the oil collecting tank (17) is opened until the oil collected in the oil collecting tank (17) reaches the lower limit threshold of oil collection; and the oil filling valve (16a) of the oil storage tank (16) is opened until the oil stored in the oil storage tank (16) reaches the upper limit threshold of oil storage.

17. A testing device, characterized in that: It includes a refrigeration system, a heater and a test terminal, wherein the refrigeration system and the heater are used together to adjust the temperature of the test terminal; The refrigeration system is the refrigeration system according to any one of claims 1 to 9, or the refrigeration system is capable of executing the control method of the refrigeration system according to any one of claims 10 to 16.

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