Lubricating oil cooling structure and air conditioning unit

Abstract

The utility model discloses a lubricating oil cooling structure and an air conditioning unit, the cooling structure comprises an oil tank and a precooling tank, an oil outlet of the oil tank is connected with an oil supply port of a compressor of the air conditioning unit through an oil supply pipe, and an air return port is connected with an evaporator of the air conditioning unit through an air return pipe; an oil inlet of the pre-cooling tank is connected with an oil return opening of the compressor through an oil inlet pipe, a liquid inlet of the pre-cooling tank is connected with a refrigerant pipe between a condenser and an evaporator of the air conditioning unit through a liquid inlet pipe and used for leading in a gas-liquid mixed refrigerant to pre-cool and mix lubricating oil, and a mixed liquid outlet of the pre-cooling tank is connected with an oil inlet of the oil tank. According to the utility model, the pre-cooling tank is arranged in front of the oil tank, so that lubricating oil can be pre-cooled in the pre-cooling tank through a refrigerant in a gas-liquid mixture state and is mixed with a gas-liquid mixed refrigerant in the pre-cooling tank at the same time. In addition, due to the fact that the liquid refrigerant is mixed with the lubricating oil when flash evaporation is conducted again in the oil tank, the heat exchange area of the refrigerant and the lubricating oil is increased through flash evaporation, and sufficient cooling is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioners, in particular to a lubricating oil cooling structure and an air conditioner unit. Background Art

[0002] For a centrifugal heat pump unit, the normal range of the lubricating oil temperature is 40°C to 60°C. This is because within this range, both the viscosity and consistency of the lubricating oil can be maintained in a good state, which can not only ensure good lubrication effect but also reduce the consumption and leakage risk of the oil. If the oil temperature is too high, on the one hand, it will accelerate the oxidation and deterioration of the lubricating oil, affecting the lubrication effect and reducing the service life of the lubricating oil.

[0003] The conventional cooling scheme is that the lubricating oil of the low-pressure stage and high-pressure stage compressors returns to the oil tank through the compressor oil return pipe; at the same time, the high-pressure liquid refrigerant enters the oil tank and evaporates into a low-temperature and low-pressure gaseous refrigerant. After the gaseous refrigerant absorbs the heat of the lubricating oil on the upper surface of the oil tank, it returns to the evaporator through the oil tank balance pipe. On the one hand, since the refrigerant only contacts the lubricating oil on the upper surface of the oil tank, the cooling of the lubricating oil is not sufficient, resulting in a slow cooling rate of the lubricating oil in the oil tank. On the other hand, since the gaseous refrigerant returns to the evaporator through the oil tank balance pipe only after contacting the lubricating oil on the upper surface of the oil tank, the heat absorbed by the refrigerant is limited. In order to reduce the oil temperature in the oil tank to the set temperature, it is necessary to increase the flow rate of the liquid refrigerant entering the oil tank, which will increase the cooling load of the unit.

[0004] The refrigerant of the centrifugal heat pump unit is of the HFO / HC series, etc. The lubricating oil is miscible with the refrigerant, and the higher the pressure, the higher the solubility of the refrigerant in the lubricating oil. Summary of the Utility Model

[0005] In order to solve the technical problem of insufficient cooling of the lubricating oil in the above-mentioned prior art, the utility model provides a lubricating oil cooling structure and an air conditioner unit.

[0006] The technical solution adopted by the utility model is as follows:

[0007] The utility model provides a lubricating oil cooling structure for an air conditioner unit, including:

[0008] An oil tank, the oil outlet of the oil tank is connected to the oil supply port of the compressor of the air conditioner unit through an oil supply pipe, and the gas return port is connected to the evaporator of the air conditioner unit through a gas return pipe;

[0009] A precooling tank, the oil inlet of the precooling tank is connected to the oil return port of the compressor through an oil inlet pipe, and the liquid inlet is connected to the refrigerant pipe between the condenser and the evaporator of the air conditioner unit through a liquid inlet pipe, for introducing a gas-liquid mixed refrigerant to precool and mix the lubricating oil, and the mixed liquid outlet is connected to the oil inlet of the oil tank.

[0010] Further, the pre-cooling tank is divided into a mixing chamber for mixing the refrigerant and the lubricating oil, and a liquid storage chamber for temporarily storing the mixed liquid of the refrigerant and the lubricating oil.

[0011] Specifically, transverse guide plates are respectively arranged on opposite sides of the upper part of the pre-cooling tank in a staggered manner to form the mixing chamber, and the oil return port and the liquid inlet are respectively arranged on opposite sides of the upper part of the pre-cooling tank; the lower part of the pre-cooling tank forms the liquid storage chamber, and the mixed liquid outlet is arranged.

[0012] Further, a gas return port is also provided at the top of the pre-cooling tank, the gas return port is connected to the evaporator through a gas return pipe, and a first gas return solenoid valve is provided on the gas return pipe.

[0013] The utility model further includes a pressure sensor for detecting the pressure in the pre-cooling tank. When the pressure in the pre-cooling tank is greater than the set upper pressure limit value, the first gas return solenoid valve is opened; when the pressure in the pre-cooling tank is less than the set lower pressure limit value, the first gas return solenoid valve is closed.

[0014] Further, the liquid inlet of the pre-cooling tank is connected to the liquid outlet side of the condenser of the air-conditioning unit through a liquid inlet pipe, and a cold oil electronic expansion valve is provided on the liquid inlet pipe.

[0015] The utility model further includes a temperature sensor for detecting the temperature of the oil tank;

[0016] When the temperature of the oil tank is higher than the upper limit value of the set temperature range, the opening degree of the cold oil electronic expansion valve is increased;

[0017] When the temperature of the oil tank is lower than the lower limit value of the set temperature range, the opening degree of the cold oil electronic expansion valve is decreased;

[0018] When the temperature of the oil tank is within the set temperature range, the cold oil electronic expansion valve maintains the current opening degree.

[0019] The utility model further includes a liquid level sensor for detecting whether the liquid level of the mixed liquid of the refrigerant and the lubricating oil in the pre-cooling tank reaches a preset height. After the air-conditioning unit is started, when the liquid level signal of the liquid level sensor is received, the compressor of the air-conditioning unit is started.

[0020] The utility model also provides an air-conditioning unit, including the above-mentioned lubricating oil cooling structure.

[0021] Preferably, the air-conditioning unit is a heat pump unit with two compressors connected in series.

[0022] Compared with the prior art, in the utility model, a pre-cooling tank is arranged in front of the fuel tank, so that the lubricating oil can be pre-cooled by the refrigerant in the gas-liquid mixture state in the pre-cooling tank, and at the same time, it is mixed with the gas-liquid mixed refrigerant in the pre-cooling tank. After the lubricating oil and the refrigerant mixture enter the fuel tank from the pre-cooling tank, the liquid refrigerant flashes again under the low-pressure environment to absorb heat and take away the heat of the lubricating oil. On the one hand, the utilization rate of the refrigerant is greatly improved by the pre-cooling method of the pre-cooling tank, thereby enhancing the cooling effect of the refrigerant; on the other hand, since the liquid refrigerant flashes again in the fuel tank when it is mixed with the lubricating oil, the flashing greatly increases the heat exchange area between the refrigerant and the lubricating oil, so that the lubricating oil can be fully cooled. Brief Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is the structural diagram of the embodiment of the present utility model;

[0025] Figure 2 It is the structural schematic diagram of the pre-cooling tank in the embodiment of the present utility model;

[0026] Figure 3 It is the control flow chart when the unit is started in the embodiment of the present utility model;

[0027] Figure 4 It is the control flow chart of the pressure of the pre-cooling tank in the embodiment of the present utility model;

[0028] Figure 5 It is the control flow chart of the temperature of the fuel tank in the embodiment of the present utility model;

[0029] 1. Evaporator; 2. Condenser; 3. Low-pressure stage compressor; 4. High-pressure stage compressor; 5. Fuel tank; 6. Pre-cooling tank; 7. First oil pump; 8. First oil supply filter; 9. Second oil pump; 10. Second oil supply filter; 11. First return air solenoid valve; 12. Pre-cooling tank pressure sensor; 13. First check valve; 14. Second check valve; 15. Cold oil electronic expansion valve; 16. Liquid level sensor; 17. Second return air solenoid valve; 18. Oil return solenoid valve; 19. Temperature sensor. Specific Embodiments

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present utility model more clear and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0031] The principle and structure of the present utility model will be described in detail below with reference to the accompanying drawings and embodiments.

[0032] In the prior art, when high-pressure liquid refrigerant enters the fuel tank, it evaporates and gasifies into low-temperature and low-pressure gaseous refrigerant. After the gaseous refrigerant absorbs the heat of the lubricating oil on the upper surface of the fuel tank, it returns to the evaporator through the fuel tank balance pipe. On the one hand, since the refrigerant only contacts the lubricating oil on the upper surface of the fuel tank, the cooling of the lubricating oil is not sufficient, resulting in a slow cooling rate of the lubricating oil in the fuel tank. On the other hand, since the gaseous refrigerant returns to the evaporator through the fuel tank balance pipe only after contacting the lubricating oil on the upper surface of the fuel tank, the heat absorbed by the refrigerant is limited. In order to reduce the oil temperature of the fuel tank to the set temperature, it is necessary to increase the flow rate of the liquid refrigerant entering the fuel tank, which will increase the cooling load of the unit.

[0033] As Figure 1 、 2 shown, the present utility model proposes a lubricating oil cooling structure, which is applied to an air-conditioning unit, such as a heat pump unit. The cooling structure specifically includes: a fuel tank 5 and a precooling tank 6;

[0034] The fuel tank 5 is provided with an oil outlet, an oil inlet and a gas return port. Its oil outlet is connected to the oil supply port of the compressor of the air-conditioning unit through an oil supply pipe, so that the lubricating oil in the fuel tank 5 can be supplied to the compressor to lubricate and cool the rotating friction part inside the compressor. The gas return port is connected to the evaporator 1 of the air-conditioning unit through a gas return pipe, so that the gaseous refrigerant after absorbing heat returns to the evaporator 1. The precooling tank 6 is provided with an oil inlet, a liquid inlet and a mixed liquid outlet; the oil inlet of the precooling tank 6 is connected to the oil return port of the compressor through an oil return pipe, so that the high-temperature lubricating oil after exchanging heat with the compressor can enter the precooling tank 6; the liquid inlet of the precooling tank 6 is connected to the liquid outlet side of the condenser 2 of the air-conditioning unit through a liquid inlet pipe. At the same time, a cold oil electronic expansion valve 15 is provided on the liquid inlet pipe to introduce the liquid refrigerant on the liquid outlet side of the condenser 2 into the precooling tank 6. The cold oil electronic expansion valve 15 evaporates and absorbs heat from the liquid refrigerant to become a gas-liquid mixture state of gas-liquid mixed refrigerant. After a part of the liquid refrigerant in the low-temperature gas-liquid mixture enters the precooling tank 6, due to the pressure reduction, it flashes and absorbs heat, taking away the heat of the lubricating oil in the precooling tank 6. The mixed liquid outlet is used to export the mixed liquid of the lubricating oil and the gas-liquid mixed refrigerant to the fuel tank 5.

[0035] The utility model sets a precooling tank 6, enabling the lubricating oil to be precooled by the refrigerant in the gas-liquid mixture state in the precooling tank 6 and mixing with the gas-liquid mixed refrigerant in the precooling tank 6 at the same time. After the lubricating oil and refrigerant mixture enter the fuel tank 5 from the precooling tank 6, the liquid refrigerant flashes and absorbs heat again under the low-pressure environment to take away the heat of the lubricating oil. On the one hand, the utilization rate of the refrigerant is greatly improved through the precooling method of the precooling tank 6, thereby enhancing the cooling effect of the refrigerant; on the other hand, since the liquid refrigerant flashes again in the fuel tank 5 while being mixed with the lubricating oil, the flashing greatly increases the heat exchange area between the refrigerant and the lubricating oil, so that the lubricating oil can be fully cooled.

[0036] In a specific embodiment, the inside of the precooling tank 6 is divided into a mixing chamber for mixing the refrigerant and the lubricating oil and a liquid storage chamber for temporarily storing the mixture of the refrigerant and the lubricating oil.

[0037] By setting the mixing chamber, the gas-liquid mixed refrigerant and the lubricating oil meet in the mixing chamber and can repeatedly collide with the inner wall of the precooling tank 6 during the falling process for mixing, so that the low-temperature gas-liquid mixed refrigerant and the high-temperature lubricating oil can be fully mixed. The liquid storage chamber can temporarily store part of the mixture of the refrigerant and the lubricating oil, enabling the lubricating oil to be fully precooled and facilitating subsequent detection of the liquid level for early warning.

[0038] Specifically, horizontal flow guiding plates are alternately arranged on the upper opposite sides of the precooling tank 6 to form the mixing chamber. The oil return port and the liquid inlet are respectively arranged on the upper opposite sides of the precooling tank 6. Specifically, the flow guiding plates on both sides are not at the same height, but are distributed in a stepped manner with one side high and the other side low, and the flow guiding plates all exceed the vertical center line of the precooling tank 6, so that the mixing flow path of the mixing chamber is arranged in a snake shape from top to bottom; the lower part of the precooling tank 6 is not provided with flow guiding plates, making the lower part a cavity-shaped liquid storage chamber, which can collect the mixture of the refrigerant and the lubricating oil flowing from the upper part. The bottom of the precooling tank 6 is provided with the mixed liquid outlet.

[0039] By setting the snake-shaped mixing flow channel, the refrigerant and the lubricating oil are fully mixed. The liquid storage chamber can temporarily store part of the mixture of the refrigerant and the lubricating oil, enabling the lubricating oil to be fully precooled, and the structure of the precooling tank 6 is simple and the cost is low.

[0040] In a specific embodiment, a gas return port is further provided at the top of the precooling tank 6. The gas return port is connected to the evaporator 1 through a gas return pipe, and a first gas return solenoid valve 11 is provided on the gas return pipe.

[0041] By setting the gas return port and the gas return solenoid valve, the pressure in the precooling tank 6 can be controlled to keep the pressure within a reasonable mixing range, so that the refrigerant and the lubricating oil in the precooling tank 6 can be fully mixed.

[0042] Such as Figure 4As shown, in a specific embodiment, it further includes a pressure sensor 12 for detecting the pressure in the pre-cooling tank 6, and a controller (the controller can be a controller of the air conditioning unit or a separate controller). When the pressure in the pre-cooling tank 6 is greater than the set pressure upper limit, the first return air solenoid valve 11 is opened, and when the pressure in the pre-cooling tank 6 is less than the set pressure lower limit, the first return air solenoid valve 11 is closed. When the pressure in the pre-cooling tank 6 is between the set pressure upper limit and the set pressure lower limit, the first return air solenoid valve 11 maintains the current state.

[0043] By controlling the first air return solenoid valve 11 , the pressure in the pre-cooling tank 6 can be maintained within a set pressure range, ensuring that the refrigerant and the lubricating oil are fully mixed.

[0044] In a specific embodiment, a cold oil electronic expansion valve 15 is provided on the liquid inlet pipe connected to the liquid inlet of the pre-cooling tank 6, which throttles the liquid refrigerant entering the pre-cooling tank 6, evaporates part of the high-temperature and high-pressure liquid refrigerant to absorb heat, and makes the refrigerant entering the pre-cooling tank 6 a low-temperature gas-liquid mixed state. After entering the pre-cooling tank 6, part of the liquid refrigerant in the low-temperature gas-liquid mixed state flashes again due to the pressure reduction to absorb heat and take away the heat of the lubricating oil in the pre-cooling tank 6.

[0045] Furthermore, it specifically includes a temperature sensor 19 for detecting the oil tank temperature (i.e., the temperature of the lubricating oil in the oil tank 5);

[0046] like Figure 5 As shown, when the oil tank temperature is higher than the upper limit of the set temperature range, the opening of the cold oil electronic expansion valve 15 is increased;

[0047] When the oil tank temperature is lower than the lower limit of the set temperature range, the opening of the cold oil electronic expansion valve 15 is reduced;

[0048] When the oil tank temperature is within the set temperature range, the cold oil electronic expansion valve 15 maintains the current opening.

[0049] That is, by controlling the opening of the electronic expansion valve, the flow of refrigerant entering the pre-cooling tank 6 for flash heat absorption is adjusted. When the opening increases, the refrigerant flow also increases, and more heat can be absorbed. When the opening decreases, the refrigerant flow decreases, and less heat can be absorbed, thereby adjusting the lubricating oil temperature in the oil tank 5.

[0050] In other embodiments, the liquid inlet pipe of the liquid inlet can also be directly connected to the liquid outlet side of the throttle valve of the air-conditioning unit, so that the refrigerant entering the pre-cooling tank 6 is in a low-temperature gas-liquid mixed state, but the oil temperature cannot be directly adjusted because directly adjusting the throttle valve of the air-conditioning unit will affect the operation of the air-conditioning unit.

[0051] Specifically, such as Figure 3As shown in the figure, the lubricating oil cooling structure further includes a liquid level sensor 16. The detection probe of the liquid level sensor 16 is set at a preset height in the liquid storage cavity of the pre-cooling tank 6. After the air-conditioning system is powered on or started, the oil pump of the oil tank 5 is first controlled to supply lubricating oil to the compressor, so that a layer of oil film is formed around the bearings in the compressor. When the liquid level sensor 16 detects a liquid level signal, it means that the lubricating oil in the liquid storage cavity reaches the preset height. At this time, the compressor of the air-conditioning unit can be normally started, and the cold oil electronic expansion valve and the oil return solenoid valve can be opened, avoiding the direct operation of the compressor with too little lubricating oil, which affects the service life of the compressor.

[0052] Specifically, a check valve is provided at the oil inlet of the pre-cooling tank 6 to prevent the lubricating oil from flowing back to the compressor.

[0053] Specifically, an oil return solenoid valve 18 is provided at the mixed liquid outlet of the pre-cooling tank 6. The oil return solenoid valve 18 is closed after the air-conditioning unit is started and opened when the liquid level sensor 16 detects a liquid level signal, ensuring the pressure in the pre-cooling tank 6 and facilitating the startup detection.

[0054] Specifically, an oil pump and an oil supply filter are provided on the oil supply pipe of the oil tank 5. The oil pump provides power for the oil supply, and the oil supply filter can filter the impurities in the lubricating oil to avoid damaging the compressor.

[0055] The present invention also proposes an air-conditioning unit, including the above-mentioned lubricating oil cooling structure.

[0056] When the air-conditioning unit uses this lubricating oil cooling structure, it can fully cool the lubricating oil of its compressor, avoiding the oxidation and deterioration of the lubricating oil, affecting the lubrication effect and reducing the service life of the lubricating oil.

[0057] In a specific embodiment, the air-conditioning unit is a heat pump unit with two compressors in series, such as a 120°C heat pump centrifuge with two compressors in series and large capacity, etc.;

[0058] The heat pump unit with two compressors in series specifically includes: a low-pressure stage compressor 3, a high-pressure stage compressor 4, a condenser 2, and an evaporator 1 that are connected in sequence and circulated. Specifically, conventional components such as a throttle valve are also provided, which will not be described in detail here.

[0059] The inlet pipe of the pre-cooling tank 6 branches into two. One is connected to the oil return port of the low-pressure stage compressor 3, and the other is connected to the oil return port of the high-pressure stage compressor 4. And check valves 13 and 14 are respectively provided on the two inlet pipes, so that the lubricating oil can enter the pre-cooling tank 6; the oil supply pipes of the oil tank 5 are also respectively provided with two, which are respectively connected to the oil supply ports of the low-pressure stage compressor 3 and the high-pressure stage compressor 4. And a first oil pump 7 and a first oil supply filter 8 are provided on the oil supply pipe corresponding to the low-pressure stage compressor 3, and a second oil pump 9 and a second oil supply filter 10 are provided on the oil supply pipe corresponding to the high-pressure stage compressor 4.

[0060] The lubricating oil temperature of a heat pump unit with two compressors in parallel is relatively high. Especially, the temperature of the lubricating oil returning to the high-pressure stage compressor is high, often deviating from the normal range of the lubricating oil temperature, which is 40°C to 60°C. Using the traditional lubricating oil cooling scheme cannot bring the lubricating oil back to the normal temperature range. However, in this application, two-stage precooling is used to cool down while fully mixing the lubricating oil and the refrigerant, enabling the refrigerant to fully absorb the heat of the lubricating oil and improving the cooling efficiency of the lubricating oil.

[0061] The specific control is as follows:

[0062] When the unit starts, the first oil pump 7 is turned on. The lubricating oil in the oil tank 5 is pumped out by the first oil pump 7 and then enters the first oil supply filter 8. After being filtered by the first oil supply filter 8, the lubricating oil enters the low-pressure stage compressor 3 through the oil supply pipe. At the same time, the second oil pump 9 is turned on. The lubricating oil in the oil tank 5 is pumped out by the second oil pump 9 and then enters the second oil supply filter. After being filtered by the second oil supply filter 10, the lubricating oil enters the high-pressure stage compressor 4 through the oil supply pipe. A layer of oil film is formed around the bearings in the compressor, which supports and lubricates the bearings while taking away the heat of the motor bearings.

[0063] The lubricating oil in the low-pressure stage compressor 3 and the high-pressure stage compressor 4 flows into the precooling tank 6 through the first one-way valve 13 and the second one-way valve 14 respectively after absorbing the heat of the motor bearings.

[0064] When the liquid level sensor 16 receives the liquid level signal, the low-pressure stage compressor 3 and the high-pressure stage compressor 4 start. At the same time, the cold oil electronic expansion valve 15 and the oil return solenoid valve 18 are opened. The lubricating oil in the precooling tank 6 returns to the oil tank 5 through the oil return solenoid valve 18.

[0065] When the liquid level sensor 16 receives the liquid level signal, the cold oil electronic expansion valve 15 is opened. The high-temperature and high-pressure liquid refrigerant in the condenser 2 enters the cold oil electronic expansion valve 15 through the cooling pipe; in the cold oil electronic expansion valve 15, part of the high-temperature and high-pressure liquid refrigerant evaporates and absorbs heat, and at this time the refrigerant is in a low-temperature gas-liquid mixture state. The low-temperature gas-liquid mixed refrigerant comes out of the cold oil electronic expansion valve 15 and enters the precooling tank 6; in the precooling tank 6, part of the liquid refrigerant flashes and vaporizes again due to the pressure reduction, taking away the heat of the lubricating oil in the precooling tank 6.

[0066] In the precooling tank 6, the liquid refrigerant dissolves in the lubricating oil under high pressure; the lubricating oil-refrigerant mixture enters the oil tank 5 through the oil return solenoid valve 18; in the oil tank 5, the liquid refrigerant in the lubricating oil-refrigerant mixture flashes and vaporizes again due to the pressure reduction, taking away the heat of the lubricating oil. The gaseous refrigerant after absorbing heat returns to the evaporator 1 with a lower pressure through the second suction solenoid valve 17. Since the liquid refrigerant is mixed with the lubricating oil, the flashing at this time greatly increases the heat exchange area between the gaseous refrigerant and the lubricating oil, so that the lubricating oil can be fully cooled.

[0067] When the pressure in the precooling tank 6 detected by the pressure sensor 12 is higher than the set upper pressure limit value, the first return air solenoid valve 11 opens, and the gaseous refrigerant that has absorbed the heat of the lubricating oil in the precooling tank 6 returns to the evaporator 1 with a lower pressure through the first return air solenoid valve 11.

[0068] When the pressure in the precooling tank 6 detected by the pressure sensor 12 is lower than the set lower pressure limit value, the first return air solenoid valve 11 closes to ensure that the pressure in the precooling tank 6 is always maintained at the set value to guarantee sufficient mixing of the refrigerant and the lubricating oil in the precooling tank 6.

[0069] When the temperature detected by the temperature sensor 19 is higher than the upper limit value of the set temperature range, the opening degree of the cold oil electronic expansion valve 15 increases, and finally the refrigerant flow rate into the oil tank 5 for flash evaporation and heat absorption increases until the temperature in the oil tank 5 decreases to the set temperature range. When the temperature detected by the temperature sensor 19 is lower than the lower limit value of the set temperature range, the opening degree of the cold oil electronic expansion valve 15 decreases, and finally the refrigerant flow rate into the oil tank 5 for evaporation and heat absorption decreases until the temperature in the oil tank 5 rises to the set range.

[0070] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0071] Unless otherwise specifically stated, the relative arrangements of the components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present utility model. At the same time, it should be understood that for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0072] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom", etc. is usually based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description. Without contrary instructions, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present utility model; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0073] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "upper...", etc. can be used here to describe the spatial positional relationship between a device or feature shown in the drawings and other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation other than the orientation described in the drawings for the device. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0074] In addition, it should be noted that using words such as "first", "second", etc. to limit the components is only for the convenience of distinguishing the corresponding components. Without separate declaration, the above words have no special meaning. Therefore, it should not be construed as a limitation on the protection scope of the present utility model.

[0075] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A lubricating oil cooling structure for an air conditioning unit, characterized in that, Comprising: An oil tank, the oil outlet of the oil tank is connected to the oil supply port of the compressor of the air-conditioning unit through an oil supply pipe, and the gas return port is connected to the evaporator of the air-conditioning unit through a gas return pipe; A precooling tank, the oil inlet of the precooling tank is connected to the oil return port of the compressor through an oil inlet pipe, and the liquid inlet is connected to the refrigerant pipe between the condenser and the evaporator of the air-conditioning unit through a liquid inlet pipe, for introducing a gas-liquid mixed refrigerant to precool and mix the lubricating oil, and the mixed liquid outlet is connected to the oil inlet of the oil tank.

2. The lubricating oil cooling structure according to claim 1, wherein, Inside the precooling tank, there are a mixing chamber for mixing the refrigerant and the lubricating oil and a liquid storage chamber for temporarily storing the mixed liquid of the refrigerant and the lubricating oil.

3. The lubricating oil cooling structure according to claim 2, characterized in that On the upper part of the precooling tank, transverse baffle plates are respectively arranged in a staggered manner on the opposite sides to form the mixing chamber, and the oil return port and the liquid inlet are respectively arranged on the opposite sides of the upper part of the precooling tank; the lower part of the precooling tank forms the liquid storage chamber, and the mixed liquid outlet is arranged.

4. The lubricating oil cooling structure according to claim 1, wherein The upper part of the precooling tank is also provided with a gas return port, the gas return port is connected to the evaporator through a gas return pipe, and a first gas return solenoid valve is arranged on the gas return pipe.

5. The lubricating oil cooling structure according to claim 4, wherein, It also includes a pressure sensor for detecting the pressure inside the precooling tank. When the pressure inside the precooling tank is greater than the set upper pressure limit value, the first gas return solenoid valve is opened. When the pressure inside the precooling tank is less than the set lower pressure limit value, the first gas return solenoid valve is closed.

6. The lubricating oil cooling structure according to claim 1, wherein The liquid inlet of the precooling tank is connected to the liquid outlet side of the condenser of the air-conditioning unit through a liquid inlet pipe, and a cold oil electronic expansion valve is arranged on the liquid inlet pipe.

7. The lubricating oil cooling structure according to claim 6, wherein It also includes a temperature sensor for detecting the temperature of the oil tank; When the temperature of the oil tank is higher than the upper limit value of the set temperature range, the opening degree of the cold oil electronic expansion valve is increased; When the temperature of the oil tank is lower than the lower limit value of the set temperature range, the opening degree of the cold oil electronic expansion valve is decreased; When the temperature of the oil tank is within the set temperature range, the cold oil electronic expansion valve maintains the current opening degree.

8. The lubricating oil cooling structure according to claim 1, wherein, It also includes a liquid level sensor for detecting whether the liquid level of the mixed liquid of the refrigerant and the lubricating oil in the precooling tank reaches a preset height. After the air-conditioning unit is started, when receiving the liquid level signal of the liquid level sensor, the compressor of the air-conditioning unit is started.

9. An air-conditioning unit, characterized in that, Comprising the lubricating oil cooling structure according to any one of claims 1-8.

10. The air conditioner unit according to claim 9, characterized in that, The air-conditioning unit is a heat pump unit with two compressors connected in series.

Images