A cooling system for a compressor lubricant and a control method thereof, a compressor

Abstract

The application discloses a compressor lubricating oil cooling system and a control method thereof and a compressor. The compressor lubricating oil cooling system comprises an oil tank provided with a first temperature sensor, the oil tank is connected with a high-position oil tank of the compressor, the top of the oil tank is communicated with the bottom of a condenser through a cold oil electronic expansion valve, the inner wall of a refrigerant inlet at the top of the oil tank is provided with an atomizing nozzle, and a pre-cooling container is arranged below the atomizing nozzle; and the oil outlet of the compressor is communicated with the pre-cooling container through an oil return electromagnetic valve. The oil recovered from the compressor is firstly input into the pre-cooling container, the liquid refrigerant is atomized into small liquid beads by the atomizing nozzle arranged in the oil tank, and the small liquid beads are uniformly sprayed into the oil in the pre-cooling container, so that the lubricating oil can be fully and uniformly cooled after heat exchange, and then the lubricating oil overflows into the oil tank. The refrigerant atomized into the small liquid beads is uniformly distributed and fully covers, and the problem of insufficient and uneven lubricating oil cooling is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration compressor technology, and more particularly to a compressor lubricating oil cooling system and its control method, wherein the compressor has the lubricating oil cooling system. Background Technology

[0002] Centrifuges in refrigeration units require lubricating oil to reduce friction and wear on internal bearings and other moving parts, ensuring smooth and stable operation. However, the high temperatures generated during operation can affect the viscosity of the lubricating oil, accelerating its oxidation and deterioration, ultimately impacting the unit's normal operation. Therefore, conventional centrifuges require heat exchange cooling for the lubricating oil to ensure it circulates at a suitable temperature for effective lubrication and cooling.

[0003] The common method for cooling lubricating oil in centrifugal heat pump units is to first discharge the lubricating oil that has absorbed heat in the compressor to an external oil tank, and then introduce the high-pressure liquid refrigerant at the bottom of the condenser into the oil tank to exchange heat with and cool the high-temperature lubricating oil inside. The cooled lubricating oil is then fed back into the compressor, thus cooling and recycling the lubricating oil.

[0004] However, due to the significant pressure difference between the condenser and the oil tank, most of the liquid refrigerant entering the oil tank will quickly transform into a low-temperature, low-pressure gaseous refrigerant. This gaseous refrigerant will then contact the upper surface of the high-temperature lubricating oil recovered from the compressor and absorb heat. The heat-absorbing gaseous refrigerant is then sent back to the evaporator through the balance pipe, simultaneously carrying away some of the heat from the lubricating oil. This heat exchange achieves the cooling effect on the lubricating oil. The small portion of liquid refrigerant that does not vaporize flows into the lubricating oil in the oil tank and is then pumped back into the high-level oil tank inside the compressor.

[0005] However, when cooling lubricating oil using the above method, the gaseous refrigerant floats above the surface of the lubricating oil in the tank, only cooling the upper surface of the oil it contacts, while the middle and lower layers of lubricating oil remain untouched. Therefore, this method is inefficient at absorbing heat from the lubricating oil. Furthermore, the remaining small amount of liquid refrigerant can only flow into localized areas of the lubricating oil due to gravity, failing to ensure that the liquid refrigerant diffuses and mixes evenly with the lubricating oil for heat exchange, ultimately resulting in insufficient cooling of the lubricating oil.

[0006] Therefore, the existing technology mainly relies on gaseous refrigerant to cool the compressor's lubricating oil, which leads to insufficient cooling and poor cooling efficiency. Summary of the Invention

[0007] To address the problems of insufficient cooling and poor cooling efficiency of compressor lubricating oil in existing technologies, this invention proposes a compressor lubricating oil cooling system and its control method, and also includes a compressor equipped with the lubricating oil cooling system. This cooling system, through the setting of relevant parameters, ensures that the lubricating oil and refrigerant enter the oil tank at a certain rate, thereby reducing the pressure difference between the oil tank and the condenser, thus achieving sufficient and efficient heat exchange and cooling of the lubricating oil for recycling.

[0008] This invention provides a cooling system for compressor lubricating oil, including an oil tank equipped with a first temperature sensor, the oil tank being connected to the high-level oil tank of the compressor, the top of the oil tank being connected to the bottom of the condenser, an atomizing nozzle being provided on the inner wall of the refrigerant inlet at the top of the oil tank, and a pre-cooling container being provided below the atomizing nozzle; the oil outlet of the compressor being connected to the pre-cooling container, and a return oil solenoid valve being provided between the oil outlet and the pre-cooling container; and a cold oil electronic expansion valve being provided between the oil tank and the condenser.

[0009] This invention utilizes a return oil solenoid valve installed between the compressor's oil outlet and the pre-cooling container in the oil tank, and a cold oil electronic expansion valve installed between the oil tank and the condenser. This allows for the setting of relevant pressure parameters in the lubricating oil cooling system before unit operation, ensuring that lubricating oil and refrigerant enter the oil tank at a specific rate. This reduces the pressure difference between the oil tank and the condenser, preventing premature vaporization of the liquid refrigerant from the condenser upon entering the oil tank and thus maintaining heat exchange efficiency. Furthermore, an atomizing nozzle is installed on the inner wall of the refrigerant inlet at the top of the oil tank, and a pre-cooling container is located below the atomizing nozzle, with the compressor's oil outlet connected to this pre-cooling container. The atomizing nozzle atomizes the liquid refrigerant into tiny droplets, which are then sprayed onto the lubricating oil in the pre-cooling container below, providing thorough and uniform heat exchange and cooling to the lubricating oil. This improves the efficiency of lubricating oil heat exchange and cooling, allowing for reuse.

[0010] Preferably, the top of the oil tank is connected to the evaporator via a return balloon valve. After heat exchange with the lubricating oil, the refrigerant vaporizes and concentrates above the inner cavity of the oil tank. Timely input of the gaseous refrigerant into the evaporator can improve the cooling efficiency of the unit and maintain the ideal pressure difference between the oil tank and the condenser, so as to keep the lubricating oil cooling system operating well.

[0011] Preferably, an oil pump and a filter are provided between the oil tank and the high-level oil tank of the compressor. This ensures that clean, cooled lubricating oil is promptly provided to the compressor, providing timely lubrication and cooling to guarantee the normal operation of the unit.

[0012] Preferably, a check valve is provided between the oil drain port and the oil return solenoid valve. This prevents the lubricating oil in the oil tank from flowing back into the compressor in case of special circumstances, thus affecting the normal operation of the compressor unit. It also facilitates the maintenance and repair of the lubricating oil cooling system.

[0013] The present invention provides a compressor having the aforementioned lubricating oil cooling system.

[0014] Preferably, the compressor is a large-capacity high-temperature heat pump centrifugal chiller unit with two compressors connected in series, and the oil tank is connected to the high-level oil tank of the low-pressure stage compressor and the high-pressure stage compressor of the unit respectively; the oil discharge ports of the high-pressure stage compressor and the low-pressure stage compressor of the unit are both connected to the pre-cooling container in the oil tank.

[0015] The lubricating oil cooling system provided by this invention can be used in various compressor units where internal components generate frictional heat during operation, thereby expanding the application scope of the lubricating oil cooling system of this invention.

[0016] Preferably, a first oil pump and a first filter are provided between the oil tank and the high-level oil tank of the low-pressure stage compressor; while a second oil pump and a second filter are provided between the oil tank and the high-level oil tank of the high-pressure stage compressor.

[0017] An oil pump and filter are installed between the oil tank and the high-level oil tank of the compressor. This allows for the rapid and efficient supply of clean, heat-cooled lubricating oil to the compressor, ensuring timely lubrication and cooling, and guaranteeing the normal operation of the unit.

[0018] Preferably, a first check valve is provided between the oil outlet of the low-pressure stage compressor and the oil return solenoid valve, and a second check valve is provided between the oil outlet of the high-pressure stage compressor and the oil return solenoid valve.

[0019] This prevents lubricating oil in the tank from flowing back into the compressor in case of special circumstances, thus affecting the normal operation of the compressor unit. It also facilitates the maintenance and repair of the lubricating oil cooling system.

[0020] The present invention also provides a control method for a compressor lubricating oil cooling system, comprising the following steps:

[0021] First, set the relevant pressure parameters of the cooling system's cold oil electronic expansion valve and return oil solenoid valve so that the pressure of the condenser and the oil tank are similar; then turn on the lubricating oil cooling system.

[0022] When the oil temperature in the tank is detected to be within the preset temperature range, the current opening of the cold oil electronic expansion valve is maintained, and the oil temperature in the tank is detected again after the preset time is reached.

[0023] If the oil temperature in the tank is detected to be lower than the lower limit of the preset temperature range, the opening of the cold oil electronic expansion valve is reduced, and the oil temperature in the tank is monitored again when the preset time is reached.

[0024] If the oil temperature in the tank is detected to be greater than the upper limit of the preset temperature range but less than the protection temperature, the opening of the cold oil electronic expansion valve is increased, and the oil temperature in the tank is monitored again when the preset time is reached.

[0025] If the oil temperature in the tank is detected to be higher than the protection temperature, the machine should be stopped for inspection.

[0026] By setting the relevant pressure parameters of the lubricating oil cooling system, the pressure difference between the oil tank and the condenser is kept small to prevent premature vaporization of the liquid refrigerant, which would hinder sufficient and effective heat exchange and cooling of the lubricating oil. Real-time monitoring of the oil tank's internal temperature allows for timely adjustment of the opening of the electronic expansion valve, ensuring an appropriate amount of refrigerant is supplied to the tank and precisely cooling the lubricating oil to meet the unit's lubrication and cooling requirements.

[0027] Preferably, the preset temperature range is 40-50℃; the protection temperature is 55℃; and the preset time is 30 seconds.

[0028] Based on the needs of testing and long-term unit operation, the optimal control parameters and monitoring time for oil tank temperature are selected to provide excellent oil temperature control.

[0029] This invention, based on a conventional compressor lubricating oil cooling system, adds an atomizing nozzle to the inner wall of the top of the oil tank, and places a pre-cooling container below the atomizing nozzle. By setting the pressure parameters corresponding to the lubricating oil system, the return oil solenoid valve between the compressor and the oil tank, and the cold oil electronic expansion valve between the oil tank and the condenser, are adjusted to allow lubricating oil and refrigerant to enter the oil tank at a certain rate, maintaining the internal pressure of the oil tank at a certain level, equivalent to setting a normal operating environment. Compared with conventional units, the parameter settings of this invention result in a smaller pressure difference between the oil tank and the condenser, to avoid premature vaporization of the liquid refrigerant, which would prevent sufficient and effective heat exchange and cooling of the lubricating oil. The lubricating oil recovered from the compressor is then input into the pre-cooling container at the top of the oil tank, where the atomizing nozzle atomizes the liquid refrigerant from the condenser into tiny droplets, which are then evenly distributed into the lubricating oil in the pre-cooling container. Because the tiny liquid refrigerant droplets sprayed from the atomizing nozzle can cover the entire surface of the pre-cooling container, the total heat exchange area between the liquid refrigerant and the lubricating oil is large and uniform during spray cooling. The evaporation of the liquid refrigerant absorbs a large amount of heat, thus providing sufficient and efficient heat exchange and cooling for the lubricating oil that initially enters the pre-cooling container. After the oil in the pre-cooling container has been fully cooled, the slowly rising lubricating oil level overflows from the periphery of the pre-cooling container and flows into the main storage space at the bottom of the oil tank. Because the atomized refrigerant droplets are evenly distributed and fully covered, the problem of insufficient and uneven cooling of the lubricating oil is effectively solved. Furthermore, the improvements made to the internal structure of the oil tank in this invention require only the addition of corresponding loads and a few connected pipelines to the unit itself, without the need for additional components. This has minimal impact on the unit's spatial structure and facilitates installation and layout. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the lubricating oil cooling system of a single-unit compressor according to the first embodiment of the present invention;

[0031] Figure 2 This is a three-dimensional schematic diagram of a large-capacity high-temperature heat pump centrifuge with two units connected in series, according to the second embodiment of the present invention.

[0032] Figure 3 for Figure 2 The main view;

[0033] Figure 4 for Figure 2 Top view;

[0034] Figure 5 for Figure 2 The right view;

[0035] Figure 6 for Figure 2 External schematic diagram of the fuel tank;

[0036] Figure 7 for Figure 6 Cross-sectional view of the fuel tank;

[0037] Figure 8 This is a schematic diagram of the lubricating oil cooling system of a large-capacity high-temperature heat pump centrifuge with two units connected in series, according to the second embodiment of the present invention.

[0038] Figure 9 This is a schematic flowchart of the compressor lubricating oil cooling system control method of the present invention.

[0039] In the picture:

[0040] 1-Evaporator;

[0041] 2-Condenser;

[0042] 03-Compressor;

[0043] 3-Low-pressure stage compressor;

[0044] 4-High-pressure stage compressor;

[0045] 5-Fuel tank;

[0046] 6-First filter;

[0047] 7-First oil pump;

[0048] 8-Second filter;

[0049] 9-Second oil pump;

[0050] 10 - First check valve;

[0051] 11-Second check valve;

[0052] 12-Return Ball Valve

[0053] 13-Atomizing nozzle;

[0054] 14 - First temperature sensor;

[0055] 15-Cold oil electronic expansion valve;

[0056] 16-Return oil solenoid valve;

[0057] 17 - Second temperature sensor;

[0058] 18 - Pre-cooled container;

[0059] 19-Gas-liquid separator. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the invention and do not constitute a limitation thereof.

[0061] like Figure 1 As shown, a cooling system for lubricating oil in a single-unit compressor according to a first embodiment of the present invention includes an oil tank 5. A first temperature sensor 14 is installed below the oil tank 5. One side of the oil tank 5 is connected to the high-level oil tank of the compressor 03 via an oil pipe. A first oil pump 7 and a first filter 6 are installed on the oil pipe between the oil tank 5 and the high-level oil tank of the compressor 03. The top of the oil tank 5 is connected to the bottom of the condenser 2 via a refrigerant pipe, and a cold oil electronic expansion valve 15 is installed on the refrigerant pipe. An atomizing nozzle 13 is installed on the inner wall of the top inlet of the oil tank 5. A pre-cooling container 18 is installed below the atomizing nozzle 13, and a second temperature sensor 17 is installed in the pre-cooling container 18. Liquid refrigerant from the condenser 2 is sprayed downward through the atomizing nozzle 13 to form tiny droplets, and the spray area can cover the entire plane of the pre-cooling container 18. The oil drain port of compressor 03 is connected to the precooling container 18 of oil tank 5 via an oil pipe. A first one-way valve 10 and a return oil solenoid valve 16 are sequentially installed between the oil drain port of compressor 03 and the precooling container 18. The top of oil tank 5 is connected to evaporator 1 via a return air valve 12. Condenser 2 is connected to evaporator 1 via a throttling device.

[0062] The lubricating oil cooling system provided by this invention can also be used for heat exchange cooling of lubricating oil in different types of refrigeration compressors. As long as the compressor exhibits frictional heat generation during operation, the compressor lubricating oil cooling system provided by this invention can be used. For example, it can be used to provide lubricating oil heat exchange cooling for single-stage two-stage compressors or two-stage compressors connected in series. Please refer to [reference needed]. Figure 8A lubricating oil cooling system for a dual-unit compressor in series is disclosed, comprising a low-pressure compressor 3 and a high-pressure compressor 4. The lower sides of the oil tank 5 are connected to the high-level oil tanks of the low-pressure compressor 3 and the high-pressure compressor 4 respectively via oil pipes. The oil drain ports of both the low-pressure and high-pressure compressors are connected to a pre-cooling container 18 within the oil tank 5.

[0063] The second embodiment of the present invention provides a large-capacity high-temperature heat pump centrifugal chiller unit with a dual-unit series connection and the aforementioned lubricating oil cooling system. For example... Figures 2-8 As shown, the unit includes an oil tank 5 equipped with a first temperature sensor 14. The lower left side of the oil tank 5 is connected to the high-level oil tank of the low-pressure stage compressor 3 via an oil pipe. A first oil pump 7 and a first filter 6 are installed on the oil pipe between the oil tank 5 and the high-level oil tank of the low-pressure stage compressor 3. The lower right side of the oil tank 5 is connected to the high-level oil tank of the high-pressure stage compressor 4 via another oil pipe. A second oil pump 9 and a second filter 8 are installed on the oil pipe between the oil tank 5 and the high-level oil tank of the high-pressure stage compressor 4.

[0064] The top of the oil tank 5 is connected to the bottom of the condenser 2 via a refrigerant pipe, and this refrigerant pipe is equipped with a cold oil electronic expansion valve 15. Figures 6-8 As shown, the inner wall of the refrigerant inlet at the top of the oil tank 5 is provided with an atomizing nozzle 13, and a pre-cooling container 18 is provided below the atomizing nozzle 13. The pre-cooling container 18 is provided with a second temperature sensor 17. Liquid refrigerant from the condenser 2 is sprayed downward through the atomizing nozzle 13 to form tiny droplets, and the spray area can cover the entire plane of the pre-cooling container 18.

[0065] The oil outlet of the low-pressure compressor 3 is connected to a pipe, and the oil outlet of the high-pressure compressor 4 is connected to another pipe. These two pipes are connected in parallel to the pre-cooling container 18 inside the oil tank 5. A return oil solenoid valve 16 is also installed on this parallel pipe. A first check valve 10 is installed on the pipe connecting to the oil outlet of the low-pressure compressor 3, and a second check valve 11 is installed on the pipe connecting to the oil outlet of the high-pressure compressor 4. The top of the oil tank 5 is connected to the evaporator 1 via a gas-liquid separator 19 and a return air valve 12. The condenser 2 is connected to the evaporator 1 via a throttling device.

[0066] like Figure 8 As shown, the working principle of the lubricating oil cooling system of the present invention will be explained using the second embodiment as an example.

[0067] The unit starts up, the first oil pump 7 and the second oil pump 9 are turned on, and the lubricating oil pumped out from the oil tank 5 respectively passes through the first filter 6 and the second filter 8. After filtering out the impurities in the oil, it is respectively input into the low-pressure stage compressor 3 and the high-pressure stage compressor 4 of the large-capacity high-temperature heat pump centrifuge in a double-machine series connection. After the lubricating oil enters the low- and high-pressure stage compressors 3 and 4, it can lubricate the bearings and other components of the compressor, reduce friction and wear, and at the same time absorb the heat generated during the operation of the compressor, causing the compressor to cool down, but the temperature of the lubricating oil rises. After the lubricating oil absorbs heat in the low-pressure stage compressor 3 and the high-pressure stage compressor 4, it flows out through the first check valve 10 and the second check valve 11 on the bottom oil discharge port pipelines of each respectively, and automatically flows into the precooling container 18 in the oil tank 5 periodically through the on-off control of the oil return solenoid valve 16 by the program, and then exchanges heat with the refrigerant from the condenser 2 for cooling and is recycled.

[0068] During this process, it is necessary to coordinately control the opening and closing of each valve in the pipeline according to the detected real-time oil temperature in the oil tank, so as to timely exchange heat and cool the lubricating oil in the oil tank and recycle it. The specific control method of the lubricating oil cooling system is as follows.

[0069] The control method of the compressor lubricating oil cooling system provided by the present invention includes the following control steps (please refer to Figure 8 、 Figure 9 ):

[0070] First, set the relevant pressure parameters of the cooling system. For example, set the pressure parameters of the cold oil electronic expansion valve 15 and the oil return solenoid valve 16. Reduce the pressure difference between the oil tank 5 and the condenser 2, that is, make the pressure difference between the oil tank 5 and the condenser 2 close to the pressure difference between the two in the existing compressor unit cooling system. Then start the oil return of the compressor unit and input the liquid refrigerant from the condenser, and implement the cooling cycle use of the compressor lubricating oil, so as to avoid the premature gasification of the liquid refrigerant entering the oil tank and affecting the heat exchange efficiency.

[0071] When the first temperature sensor 14 detects that the oil temperature T5 in the oil tank 5 is within the preset temperature range of 40 - 50 °C, that is, 40 °C < T5 < 50 °C, keep the current opening of the cold oil electronic expansion valve 15 running, that is, keep the current refrigerant flow rate. When the preset time is reached, that is, when t = 30 seconds, the first temperature sensor 14 detects the oil temperature T5 in the oil tank again.

[0072] If it is detected that the oil temperature T5 in the oil tank is less than the lower limit value of the preset temperature range, that is, T5 < 40 °C, then reduce the opening of the cold oil electronic expansion valve 15 to run, reduce the refrigerant flow rate, and reduce the cooling efficiency until the oil temperature T5 in the oil tank rises back to the preset temperature range of 40 - 50 °C. And when the preset time is reached, that is, when t = 30 seconds, the first temperature sensor 14 continues to detect the oil temperature T5 in the oil tank.

[0073] If it is detected that the oil temperature T5 in the fuel tank is greater than the upper limit value of the preset temperature range but less than the protection temperature, that is, when 50°C < T5 < 55°C, the opening of the cold oil electronic expansion valve 15 is increased for operation. This increases the flow rate of the liquid refrigerant from the condenser 2 to improve the cooling efficiency until the oil temperature T5 in the fuel tank 5 drops back to the preset temperature range of 40 - 50°C. And when the preset time is reached, that is, when t = 30 seconds, the first temperature sensor 14 continues to detect the oil temperature T5 in the fuel tank.

[0074] When the first temperature sensor 14 detects that the oil temperature T5 in the fuel tank is greater than the protection temperature, that is, when 55°C < T, the machine stops for inspection.

[0075] The specific values of the preset temperature range, protection temperature, and preset time can be selected according to different situations. The second temperature sensor 17 can assist in monitoring the oil temperature in the pre-cooling container 18.

[0076] When the cold oil electronic expansion valve 15 is opened, the lubricating oil cooling system delivers an appropriate amount of liquid refrigerant from the bottom of the condenser 2, which is sprayed through the atomizing nozzle 13 in the fuel tank 5, causing the liquid refrigerant to be converted into micron-sized tiny droplets and sprayed into the fuel tank 5, which can cool the lubricating oil in the upper layer of the pre-cooling container 18. Since the atomizing nozzle 13 is set at a certain height above the pre-cooling container 18, and the spraying area of the atomized refrigerant basically covers the entire plane of the pre-cooling container 18. The atomized liquid refrigerant is scattered in the spraying area in the form of dense, small-volume, evenly distributed tiny droplets and is evenly mixed with the lubricating oil for heat exchange cooling. In this way, the tiny droplet form of the refrigerant can ensure that it has sufficient heat exchange area, improving the heat exchange cooling efficiency between it and the lubricating oil. After a part of the atomized refrigerant exchanges heat with the upper-layer lubricating oil in the pre-cooling container 18, it evaporates and gasifies, and the remaining atomized refrigerant is evenly mixed with the lubricating oil in the form of tiny droplets and continues to exchange heat and cool, and the refrigerant evaporates and gasifies after absorbing heat. After the oil in the pre-cooling container 18 is cooled, the oil level rises and overflows to the lower fuel tank 5 for storage over the top of the side plate of the pre-cooling container 18. This can effectively avoid the problem of uneven and insufficient heat exchange cooling caused by the direct injection of the liquid refrigerant from the condenser 2 into a local area of the lubricating oil in the fuel tank 5 for cooling. The refrigerant gasified by absorbing heat from the lubricating oil then flows through the gas-liquid separator 19 at the top of the fuel tank 5 and into the evaporator 1 via the return ball valve 12 (as Figure 6 、 Figure 7 shown).

[0077] In this invention, an atomizing nozzle and a pre-cooling container are added in the fuel tank. By setting the corresponding pressure parameters of the lubricating oil system, adjusting the oil return solenoid valve between the compressor and the fuel tank and the cold oil electronic expansion valve between the fuel tank and the condenser, the pressure difference between the fuel tank and the condenser during operation is made smaller, avoiding premature gasification of the refrigerant and ensuring sufficient and effective heat exchange cooling of the lubricating oil.

[0078] The lubricating oil recovered from the compressor is fed into a pre-cooling container at the top of the oil tank. Then, an atomizing nozzle atomizes the liquid refrigerant from the condenser into tiny droplets, which are evenly distributed into the lubricating oil within the pre-cooling container. Because the tiny droplets of refrigerant sprayed from the nozzle can cover the entire surface of the pre-cooling container, the total heat exchange area between the refrigerant and the lubricating oil is large and uniform during spray cooling. The evaporation of the liquid refrigerant absorbs a large amount of heat, thus achieving sufficient and efficient heat exchange and cooling of the lubricating oil that initially enters the pre-cooling container. After the oil in the pre-cooling container has been fully cooled, the slowly rising lubricating oil level overflows from the top perimeter of the pre-cooling container and flows into the main storage space at the bottom of the oil tank for recycling.

[0079] Because the refrigerant is atomized into tiny droplets and evenly distributed with comprehensive coverage, it effectively solves the problems of insufficient and uneven cooling of lubricating oil, thus improving heat exchange and cooling efficiency. Furthermore, the improvements made to the internal structure of the oil tank in this invention mean that the unit itself only needs to add corresponding loads and a few connected pipes, without requiring any new components. This has minimal impact on the unit's spatial structure and facilitates installation and layout.

[0080] It should be noted that the terminology used in this specification is for describing specific embodiments only and is not intended to limit the invention. Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the technical features and steps set forth in these embodiments do not limit the scope of protection of the invention. Techniques, methods, and devices known to those skilled in the art are not discussed in detail here, but where appropriate, such techniques, methods, and devices should be considered part of this specification. Any specific values ​​in this specification should be interpreted as merely exemplary and do not constitute a limitation of the invention.

[0081] For ease of description, the terms used in the specification to describe position, such as "above", "to the left of", "in front of", etc., are only used to describe the spatial positional relationship between a certain component and other components in the embodiment shown in the figure. When the position of the component is different, the relative position will change. Therefore, the positional relationship of the embodiment in the figure should not be construed as limiting the present invention.

[0082] Furthermore, it should be noted that the use of terms such as "first" and "second" in the specification is merely for distinguishing similar components and does not imply a sequential order; therefore, it should not be construed as limiting the scope of protection of this invention. The above description is only a specific embodiment of this invention. It should be pointed out that any modifications, equivalent substitutions, and variations made within the spirit and framework of this invention should be included within the scope of protection of this invention.

Claims

1. A control method for a compressor lubricating oil cooling system, characterized in that, The compressor lubricating oil cooling system includes an oil tank equipped with a first temperature sensor, which is connected to the compressor's high-level oil tank. The top of the oil tank is connected to the bottom of the condenser via a cold oil electronic expansion valve. An atomizing nozzle is provided on the inner wall of the refrigerant inlet at the top of the oil tank, and a pre-cooling container is located below the atomizing nozzle. The compressor's oil outlet is connected to the pre-cooling container via a return oil solenoid valve. The control method includes the following steps: The pressure parameters of the cooling system's electronic expansion valve for cold oil and the return solenoid valve are set to reduce the pressure difference between the oil tank and the condenser, starting the return of oil from the compressor unit and the input of liquid refrigerant from the condenser, thus implementing the cooling and recycling of the compressor lubricating oil; the tiny liquid droplets of refrigerant sprayed from the atomizing nozzle cover the entire surface of the precooling container; part of the atomized refrigerant exchanges heat with the upper layer of lubricating oil in the precooling container, and the remaining atomized refrigerant mixes evenly with the lubricating oil in the form of tiny droplets, continuing to exchange heat and cool; after the oil in the precooling container is cooled, the oil level rises and overflows over the top of the side plate of the precooling container into the lower oil tank for storage; When the oil temperature in the tank is detected to be within the preset temperature range, the current opening of the cold oil electronic expansion valve is maintained, and the oil temperature in the tank is detected again after the preset time is reached. If the oil temperature in the tank is detected to be lower than the lower limit of the preset temperature range, the opening of the cold oil electronic expansion valve is reduced, and the oil temperature in the tank is monitored again when the preset time is reached. If the oil temperature in the tank is detected to be greater than the upper limit of the preset temperature range but less than the protection temperature, the opening of the cold oil electronic expansion valve is increased, and the oil temperature in the tank is monitored again when the preset time is reached. If the oil temperature in the tank is detected to be higher than the protection temperature, the machine should be stopped for inspection.

2. The control method for the cooling system of compressor lubricating oil as described in claim 1, characterized in that, The preset temperature range is 40-50℃; the protection temperature is 55℃; and the preset time is 30 seconds.

3. The control method for the cooling system of compressor lubricating oil as described in claim 1, characterized in that, The top of the oil tank is connected to the evaporator via a return balloon valve.

4. The control method for the cooling system of compressor lubricating oil as described in claim 1, characterized in that, An oil pump and a filter are installed between the oil tank and the high-level oil tank of the compressor.

5. The control method for the cooling system of compressor lubricating oil as described in claim 1, characterized in that, A one-way valve is provided between the oil drain port and the oil return solenoid valve.

6. The control method for the cooling system of compressor lubricating oil as described in claim 1, characterized in that, The compressor is a large-capacity high-temperature heat pump centrifugal chiller unit with two units connected in series. The oil tank is connected to the high-level oil tank of the low-pressure stage compressor and the high-pressure stage compressor of the unit, respectively. The oil discharge ports of the high-pressure and low-pressure stage compressors of the unit are connected to the pre-cooling container in the oil tank.

7. The control method for the cooling system of compressor lubricating oil as described in claim 6, characterized in that, A first oil pump and a first filter are provided between the oil tank and the high-level oil tank of the low-pressure stage compressor; a second oil pump and a second filter are provided between the oil tank and the high-level oil tank of the high-pressure stage compressor.

8. The control method for the cooling system of compressor lubricating oil as described in claim 6, characterized in that, A first check valve is provided between the oil outlet of the low-pressure stage compressor and the oil return solenoid valve, and a second check valve is provided between the oil outlet of the high-pressure stage compressor and the oil return solenoid valve.

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