Centrifugal unit injection oil return system

Abstract

The utility model relates to the technical field of centrifugal units, and provides a centrifugal unit injection oil return system which comprises a compressor body, an evaporator body, an oil recovery device and a condenser body. And the IGV body is fixedly arranged on the outer surface of the evaporator body, and an IGV injection oil return inlet is formed in the outer surface of the IGV body. According to the utility model, firstly, when oil recovery operation of a refrigerating system is carried out, an oil return opening is formed in an oil-rich area of the evaporator body, a mixture of oil and a refrigerant is sucked into the ejector II, an ejection oil return principle is that high-pressure refrigerant gas is led out from a high-pressure refrigerant outlet of a compressor, and when the high-pressure refrigerant gas passes through an ejection nozzle, a strong suction force is generated due to an ejection effect; by means of low pressure of the IGV shell, part of refrigerant gas in the injected oil and refrigerant mixture is gasified, excessive liquid refrigerants are prevented from being sucked into the oil tank body, and the problem that due to the fact that the pressure is too low, the refrigerants are gasified and foamed, oil is brought into a compressor cavity, and oil leakage is caused is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of centrifugal units, in particular to an oil injection return system of a centrifugal unit. Background Art

[0002] A centrifugal refrigeration unit, or centrifugal chiller, consists of a centrifugal refrigeration compressor, evaporator, condenser, main motor, air recovery device, lubrication system, control cabinet and starting cabinet. Some of these components are assembled in a decentralized manner, but most are "assembled" units in which various components are combined together. The units are divided into fully enclosed, semi-enclosed and open types. For centrifugal units, in a flooded evaporator, the refrigerant flows through the shell and the water flows through the tube. At this time, the refrigerant changes phase heat outside the tube, and the lubricating oil accumulates at the bottom of the evaporator after the refrigerant evaporates. This not only affects the shell and tube heat exchange, but also causes the lubricating oil in the compressor to become less and less.

[0003] Although current technology has many advantages, its disadvantage is that the commonly used method of oil return by injection for centrifuges is to open an oil return port on the evaporator, and inject the mixture of oil and refrigerant back to the compressor oil tank through oil injection. The refrigerant injected into the oil tank is then heated by the oil heater to become a gaseous refrigerant and return to the compressor suction end. Because the amount of lubricating oil in the system is in a dynamic balance state, too little injection will result in insufficient oil return, and too much injection will inevitably lead to too much refrigerant liquid being sucked into the compressor oil tank. Too much liquid refrigerant entering the oil tank will not only affect the oil return effect, but also cause the oil supply temperature to become low and there will be too much refrigerant in the oil tank when the machine is started, resulting in the problem of oil leakage caused by the refrigerant vaporization and foaming due to low pressure. Utility Model Content

[0004] The purpose of the utility model is to solve the problem in the prior art that the commonly used oil return method of the centrifuge is to open an oil return port on the evaporator, and to inject the mixture of oil and refrigerant back to the compressor oil tank through the oil return injection. The refrigerant injected into the oil tank is then converted into gaseous refrigerant by the heating effect of the oil heater and returned to the suction end of the compressor. Since the amount of lubricating oil in the system is in a dynamic balance state, the oil return will be insufficient if the injection is too little, and too much refrigerant liquid will be sucked into the compressor oil tank if the injection is too much. Too much liquid refrigerant enters the oil tank, which not only affects the oil return effect, but also causes the oil supply temperature to become low and there is too much refrigerant in the oil tank when the machine is started, thereby causing the refrigerant to vaporize and foam due to too low pressure, bringing oil into the compressor cavity and causing oil leakage.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: a centrifugal unit injection oil return system: the system includes a compressor body and an evaporator body, and also includes:

[0006] Oil recovery device and condenser body;

[0007] The IGV body is fixedly arranged on the outer surface of the evaporator body, and the outer surface of the IGV body is provided with an IGV injection oil return inlet;

[0008] An oil return port of the oil tank is provided on the outer surface of the compressor body near the top;

[0009] A high-pressure refrigerant outlet is provided on the outer surface of the compressor body near the bottom, and the port of the high-pressure refrigerant outlet is fixedly connected to an ejector 2;

[0010] Two evaporator oil return ports are provided on the outer surface of the evaporator body, and one of the evaporator oil return ports is connected to the suction port of the second ejector through a hose;

[0011] The IGV ejection return oil outlet is opened on the outer surface of the IGV body near the bottom, and the port of the IGV ejection return oil outlet is fixedly connected to ejector 1.

[0012] As a preferred embodiment, the oil tank body is fixedly installed at the bottom of the compressor body, the other end of the ejector 2 is fixedly connected to the port of the IGV injection return oil inlet, and one end of the ejector 1 is fixedly connected to the port of the high-pressure refrigerant outlet.

[0013] The technical effect of adopting the above further solution is that part of the refrigerant is vaporized and finally enters the suction end of the compressor from the gaseous refrigerant outlet, and the remaining mixture of oil and refrigerant enters the ejector 2 through the oil outlet.

[0014] As a preferred embodiment, the other end of the ejector 1 is connected to the port of the oil return port of the oil tank through a hose, and an electromagnetic valve is provided at the inlet pipe of the ejector 2, and one end of the electromagnetic valve is fixedly set in the inlet pipe of the evaporator oil return port.

[0015] The technical effect of adopting the above further scheme is: a solenoid valve is installed on the ejector 2 and the evaporator body ejection return oil inlet pipeline. The solenoid valve can be opened for a period of time, and the actual time can be set by the controller according to the requirements, and then closed for a period of time to control the return oil amount of the evaporator body.

[0016] As a preferred embodiment, an oil inlet is provided at the top of the oil recovery device near the edge, a gas refrigerant outlet is provided at the top of the oil recovery device near the edge, a liquid refrigerant outlet is provided on one side of the outer surface of the oil recovery device, and a condenser liquid outlet is provided on the outer surface of the condenser body.

[0017] The technical effect of adopting the above-mentioned further scheme is: an oil return port is opened in the oil-rich area of the evaporator, a mixture of oil and refrigerant is sucked into the oil recovery device from the oil inlet, and the high-temperature liquid refrigerant in the condenser enters the oil recovery device from the condenser outlet through the refrigerant inlet, and the high-temperature liquid refrigerant heats the mixture of oil and refrigerant.

[0018] As a preferred embodiment, a refrigerant liquid inlet is provided on the other side of the outer surface of the oil recovery device, and an oil outlet is provided at the bottom of the oil recovery device near the edge.

[0019] The technical effect of adopting the above further solution is that the liquid refrigerant entering from the refrigerant liquid inlet heats the oil and refrigerant mixture, cools down, flows out from the liquid refrigerant outlet and enters the evaporator body.

[0020] As a preferred embodiment, the oil outlet is connected to the port of the second ejector through a pipeline.

[0021] The technical effect of adopting the above-mentioned further scheme is that the mixture of oil and refrigerant is sucked into the ejector 2. The principle of oil return injection is to draw out the high-pressure refrigerant gas from the high-pressure refrigerant outlet of the compressor. When it passes through the ejector nozzle, a strong suction force is generated due to the injection action, which sucks out the mixture of oil and refrigerant at the bottom of the evaporator body.

[0022] As a preferred embodiment, the port of the condenser liquid outlet is connected to the inside of the refrigerant liquid inlet through a pipeline, and the port of the gas refrigerant outlet is connected to the suction end of the compressor body through a pipeline.

[0023] The technical effect of adopting the above further solution is: utilizing the low pressure of the IGV shell to gasify part of the refrigerant gas in the injected oil and refrigerant mixture.

[0024] As a preferred embodiment, the liquid refrigerant outlet port is connected to the inside of the evaporator body through a pipeline, and the oil inlet port is connected to the oil return port of another evaporator through a hose.

[0025] The technical effect of adopting the above further scheme is: the mixture of oil and refrigerant in the oil recovery device is sucked out, mixed with the high-pressure gas sprayed from the nozzle, and then transported to the IGV injection return oil inlet through the nozzle outlet pipeline due to the low pressure in the IGV.

[0026] Compared with the prior art, the advantages and positive effects of the present invention are:

[0027] 1. The utility model, when performing the oil recovery operation of the refrigeration system, firstly, opens an oil return port in the oil-rich area of the evaporator body, and the mixture of oil and refrigerant is sucked into the ejector 2. The principle of the oil return injection is to draw out the high-pressure refrigerant gas from the high-pressure refrigerant outlet of the compressor. When it passes through the ejector nozzle, a strong suction force is generated due to the ejection effect, which sucks out the oil and refrigerant mixture at the bottom of the evaporator body, and after mixing with the high-pressure gas ejected from the nozzle, it is transported to the IGV oil return injection inlet through the nozzle outlet pipeline. The pressure is low, part of the refrigerant in the oil and refrigerant mixture is vaporized, and the rest of the refrigerant and oil mixture flows downward with the shell of the IGV body and flows out from the IGV ejector oil return outlet together with the oil gathered in the IGV body into the ejector 1. One end of the ejector 1 is connected to the high-pressure refrigerant outlet, and the other end is connected to the oil return port of the oil tank. A solenoid valve is installed on the ejector 2 and the evaporator oil return port inlet pipeline. The solenoid valve opens for a period of time, which has been set by the controller before, and then closes for a period of time to control the evaporator itself. The oil return volume of the evaporator body is reduced to prevent excessive liquid refrigerant from being sucked into the oil tank, thereby achieving refrigeration. Compared with traditional centrifugal units, when the evaporator body is injected with return oil, the return oil is no longer directly injected into the high-pressure oil tank body, but directly injected into the IGV shell, thereby utilizing the low pressure of the IGV shell to vaporize part of the refrigerant gas in the injected oil and refrigerant mixture, preventing excessive refrigerant liquid from entering the compressor oil tank body. The two oil recovery systems can effectively solve the problem of lubricating oil accumulation in the oil-rich area of the evaporator body and affecting the heat exchange effect. At the same time, it also prevents excessive refrigerant liquid from entering the compressor oil tank body. Traditional oil recovery systems are generally manual valves, which do not control the return oil volume, and the injection volume is fixed. This oil return system has also been improved in terms of control strategy. A solenoid valve is added to the return oil pipeline. The return oil volume of the evaporator is controlled by controlling the switching state of the solenoid valve to prevent excessive liquid refrigerant from being sucked into the oil tank body, and solve the problem of refrigerant vaporization and foaming caused by low pressure, which brings oil to the compressor cavity and causes oil leakage.

[0028] 2. In the present invention, when performing oil recovery operation of the heating system, an oil return port is opened in the oil-rich area of the evaporator, and the mixture of oil and refrigerant is sucked into the oil recovery device from the oil inlet. The high-temperature liquid refrigerant in the condenser enters the oil recovery device from the condenser outlet through the refrigerant inlet. The high-temperature liquid refrigerant heats the mixture of oil and refrigerant. Part of the refrigerant is vaporized and finally enters the compressor suction end from the gaseous refrigerant outlet. The rest of the oil and refrigerant mixture enters the ejector 2 through the oil outlet. The liquid refrigerant that enters from the refrigerant inlet After the refrigerant heats the oil and refrigerant mixture and cools down, it flows out from the liquid refrigerant outlet and enters the evaporator body. Through the heating effect of the oil recovery device, part of the refrigerant is vaporized and enters the suction end of the evaporator to prevent excessive liquid refrigerant from entering the compressor oil tank body. One end of the ejector is connected to the high-pressure refrigerant outlet, one end is connected to the IGV ejection oil return inlet, and the other end is connected to the oil outlet. The ejection oil return principle is to draw out high-pressure refrigerant gas from the high-pressure refrigerant outlet of the compressor body. When it passes through the ejection nozzle, a strong The suction force sucks out the mixture of oil and refrigerant from the oil recovery device, mixes it with the high-pressure gas ejected from the nozzle, and is then transported to the IGV injection oil return inlet through the nozzle outlet pipe. Due to the low pressure in the IGV, part of the refrigerant in the oil and refrigerant mixture is vaporized, and the remaining refrigerant and oil mixture flows downward with the IGV shell and flows out from the IGV injection oil return outlet together with the oil gathered in the IGV into the ejector 1. One end of the ejector 1 is connected to the high-pressure refrigerant outlet, and the other end is connected to the oil return port of the oil tank body. A solenoid valve is installed on the ejector 2 and the evaporator body injection oil return inlet pipeline. The solenoid valve can be opened for a period of time and the actual time can be set by the controller according to the requirements, and then closed for a period of time to control the oil return amount of the evaporator body to prevent too much liquid refrigerant from being sucked into the oil tank body, thereby achieving heating. Compared with the above-mentioned refrigeration oil return system, an oil recovery device is added to heat the recovered oil and refrigerant mixture by using the high-temperature refrigerant liquid of the condenser body to achieve pre-separation of oil and refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the planar structure of a refrigeration system of a centrifugal unit oil return system provided by the utility model;

[0030] Figure 2 This is a schematic diagram of the planar structure of a heating system of a centrifugal unit oil return system provided by the utility model.

[0031] Legend:

[0032] 1. Evaporator body; 2. IGV body; 3. Oil tank body; 4. Ejector 1; 5. Ejector 2; 6. Solenoid valve; 7. IGV ejector oil return inlet; 8. IGV ejector oil return outlet; 9. High-pressure refrigerant outlet; 10. Oil tank return oil port; 11. Oil recovery device; 12. Condenser body; 13. Evaporator oil return port; 14. Condenser liquid outlet; 15. Oil inlet; 16. Liquid refrigerant outlet; 17. Oil outlet; 18. Gas refrigerant outlet; 19. Refrigerant liquid inlet; 20. Compressor body. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1, please refer to Figure 1-Figure 2 The utility model provides a technical solution: a centrifugal unit induced oil return system, including a compressor body 20 and an evaporator body 1, and also including: an oil recovery device 11 and a condenser body 12; an IGV body 2, fixedly arranged on the outer surface of the evaporator body 1, and an IGV induced oil return inlet 7 is opened on the outer surface of the IGV body 2; an oil tank return oil port 10, opened on the outer surface of the compressor body 20 near the top; a high-pressure refrigerant outlet 9, opened on the outer surface of the compressor body 20 near the bottom, and the port of the high-pressure refrigerant outlet 9 is fixedly connected to an ejector 5; two evaporator return oil ports 13, opened on the outer surface of the evaporator body 1, and one of the evaporators The evaporator oil return port 13 is connected to the suction port of the ejector 2 5 through a hose; the IGV ejection oil return outlet 8 is opened on the outer surface of the IGV body 2 near the bottom, and the port of the IGV ejection oil return outlet 8 is fixedly connected to the ejector 1 4, and the oil tank body 3 is fixedly installed at the bottom of the compressor body 20. The other end of the ejector 2 5 is fixedly connected to the port of the IGV ejection oil return inlet 7, one end of the ejector 1 4 is fixedly connected to the port of the high-pressure refrigerant outlet 9, and the other end of the ejector 1 4 is connected to the port of the oil tank return port 10 through a hose. A solenoid valve 6 is provided at the inlet pipeline of the ejector 2 5, and one end of the solenoid valve 6 is fixedly provided in the inlet pipeline of the evaporator oil return port 13.

[0035] In this embodiment, when performing the oil recovery operation of the refrigeration system, first, an oil return port is opened in the oil-rich area of the evaporator body 1, and the mixture of oil and refrigerant is sucked into the ejector 2 5. The principle of the oil return injection is to draw out the high-pressure refrigerant gas from the compressor high-pressure refrigerant outlet 9. When passing through the ejection nozzle, a strong suction force is generated due to the injection effect, which sucks out the oil and refrigerant mixture at the bottom of the evaporator body 1. After mixing with the high-pressure gas ejected from the nozzle, it is transported to the IGV oil return injection inlet 7 through the nozzle outlet pipeline. Due to the pressure in the IGV body 2, the high-pressure refrigerant gas is sucked out. The pressure is low, part of the refrigerant in the oil and refrigerant mixture is vaporized, and the rest of the refrigerant and oil mixture flows downward with the shell of the IGV body 2 and flows out from the IGV injection oil return outlet 8 together with the oil accumulated in the IGV body 2 into the ejector 1 4. One end of the ejector 1 4 is connected to the high-pressure refrigerant outlet 9, and the other end is connected to the oil tank return port 10. A solenoid valve 6 is installed on the inlet pipeline of the ejector 2 5 and the evaporator return port 13. The solenoid valve 6 is opened for a period of time, which has been set by the controller before, and then closed for a period of time to control The return oil of the evaporator body 1 prevents too much liquid refrigerant from being sucked into the oil tank, thereby achieving refrigeration. Compared with the traditional centrifugal unit, when the evaporator body 1 is injected with oil, the return oil is no longer directly injected into the high-pressure oil tank body 3, but directly injected into the IGV shell, thereby utilizing the low pressure of the IGV shell to vaporize part of the refrigerant gas in the injected oil and refrigerant mixture, preventing too much refrigerant liquid from entering the compressor oil tank body 3. The two oil recovery systems can effectively solve the problem of lubricating oil accumulating in the oil-rich area of the evaporator body 1 and affecting the cooling effect. The problem of heat exchange effect is solved, and at the same time, too much refrigerant liquid is prevented from entering the compressor oil tank body 3. Traditional oil recovery systems are generally manual valves, which do not control the return oil volume. The injection volume is certain. The oil return system is also improved in the control strategy. A solenoid valve 6 is added to the return oil pipeline. The return oil volume of the evaporator is controlled by controlling the switching state of the solenoid valve 6 to prevent too much liquid refrigerant from being sucked into the oil tank body 3, and solves the problem of oil leakage caused by the refrigerant vaporization and foaming due to low pressure.

[0036] Example 2, as Figure 1-Figure 2As shown, an oil inlet 15 is provided at the top near the edge of the oil recovery device 11, a gas refrigerant outlet 18 is provided at the top near the edge of the oil recovery device 11, a liquid refrigerant outlet 16 is provided on one side of the outer surface of the oil recovery device 11, a condenser liquid outlet 14 is provided on the outer surface of the condenser body 12, a refrigerant liquid inlet 19 is provided on the other side of the outer surface of the oil recovery device 11, an oil outlet 17 is provided at the bottom near the edge of the oil recovery device 11, the oil outlet 17 is connected to the port of the ejector 2 5 through a pipe, the port of the condenser liquid outlet 14 is connected to the inside of the refrigerant liquid inlet 19 through a pipe, the port of the gas refrigerant outlet 18 is connected to the suction end of the compressor body 20 through a pipe, the port of the liquid refrigerant outlet 16 is connected to the inside of the evaporator body 1 through a pipe, and the port of the oil inlet 15 is connected to the port of the other evaporator oil return port 13 through a hose.

[0037] In this embodiment, when the oil recovery operation of the heating system is performed, the evaporator oil return port 13 is opened in the oil-rich area of the evaporator, and the mixture of oil and refrigerant is sucked into the oil recovery device 11 from the oil inlet 15. The high-temperature liquid refrigerant in the condenser enters the oil recovery device 11 from the condenser liquid outlet 14 through the refrigerant liquid inlet 19. The high-temperature liquid refrigerant heats the mixture of oil and refrigerant. Part of the refrigerant is vaporized and finally enters the compressor suction end from the gas refrigerant outlet 18. The rest of the oil and refrigerant mixture enters the ejector 2 5 through the oil outlet 17 and is discharged from the refrigerant liquid inlet The liquid refrigerant entering 19 heats the oil and refrigerant mixture and then cools down and flows out from the liquid refrigerant outlet 16 and enters the evaporator body 1. Through the heating effect of the oil recovery device 11, part of the refrigerant is vaporized and enters the suction end of the evaporator to prevent excessive liquid refrigerant from entering the compressor oil tank body 3. One end of the ejector 2 5 is connected to the high-pressure refrigerant outlet 9, one end is connected to the IGV ejection return oil inlet 7, and one end is connected to the oil outlet 17. The ejection return oil principle is to draw out the high-pressure refrigerant gas from the high-pressure refrigerant outlet 9 of the compressor body 20. When passing through the ejection nozzle, due to The jet action generates a strong suction force to suck out the mixture of oil and refrigerant from the oil recovery device 11, and after mixing with the high-pressure gas ejected from the nozzle, it is transported to the IGV injection oil return inlet 7 through the nozzle outlet pipeline. Due to the low pressure in the IGV, part of the refrigerant in the oil and refrigerant mixture is vaporized, and the remaining refrigerant and oil mixture flows downward with the IGV shell and flows out from the IGV injection oil return outlet 8 together with the oil accumulated in the IGV into the ejector 4. One end of the ejector 4 is connected to the high-pressure refrigerant outlet 9, and the other end is connected to the oil tank body 3 return. The oil port is equipped with a solenoid valve 6 on the ejector 2 5 and the evaporator body 1 injection return oil inlet pipeline. The solenoid valve 6 is opened for a period of time, and the actual time can be set by the controller according to the needs, and then closed for a period of time to control the return oil amount of the evaporator body 1 to prevent too much liquid refrigerant from being sucked into the oil tank body 3, thereby achieving heating. Compared with the above-mentioned refrigeration oil return system, an oil recovery device 11 is added to heat the recovered oil and refrigerant mixture using the high-temperature refrigerant liquid of the condenser body 12 to achieve pre-separation of oil and refrigerant.

[0038] Working principle: First, when performing the oil recovery operation of the refrigeration system, an oil return port is opened in the oil-rich area of the evaporator body 1, and the mixture of oil and refrigerant is sucked into the ejector 2 5. The principle of oil return injection is to draw out high-pressure refrigerant gas from the compressor high-pressure refrigerant outlet 9. When passing through the ejection nozzle, a strong suction force is generated due to the injection effect, which sucks out the oil and refrigerant mixture at the bottom of the evaporator, and after mixing with the high-pressure gas ejected from the nozzle, it is transported to the IGV ejection oil return inlet 7 through the nozzle outlet pipeline. Since the pressure in the IGV body 2 is relatively low, part of the refrigerant in the oil and refrigerant mixture is vaporized, and the remaining refrigerant and oil mixture flows downward with the shell of the IGV body 2 and is ejected from the IGV together with the oil gathered in the IGV body 2. The return oil outlet 8 flows out into the ejector 1 4. One end of the ejector 1 4 is connected to the high-pressure refrigerant outlet 9, and the other end is connected to the oil tank return oil port 10. A solenoid valve 6 is installed on the inlet pipeline of the ejector 2 5 and the evaporator oil return port 13. The solenoid valve 6 is opened for a period of time, and the required time has been set by the controller before, and then closed for a period of time to control the return oil amount of the evaporator body 1 to prevent too much liquid refrigerant from being sucked into the oil tank, thereby achieving refrigeration. Compared with the traditional centrifugal unit, when the evaporator body 1 is injected with return oil, the return oil is no longer directly injected into the high-pressure oil tank body 3, but directly injected into the IGV shell, thereby utilizing the low pressure of the IGV shell to vaporize part of the refrigerant gas in the injected oil and refrigerant mixture. Prevent excessive refrigerant liquid from entering the compressor oil tank body 3, and when performing the oil recovery operation of the heating system, open the evaporator oil return port 13 in the oil-rich area of the evaporator, and the mixture of oil and refrigerant is sucked into the oil recovery device 11 from the oil inlet 15. The high-temperature liquid refrigerant in the condenser enters the oil recovery device 11 from the condenser liquid outlet 14 through the refrigerant liquid inlet 19. The high-temperature liquid refrigerant heats the mixture of oil and refrigerant. Part of the refrigerant is vaporized and finally enters the compressor suction end from the gas refrigerant outlet 18. The rest of the oil and refrigerant mixture enters the ejector 2 5 through the oil outlet 17. The liquid refrigerant entering from the refrigerant liquid inlet 19 heats the oil and refrigerant mixture, cools it down, and then flows out from the liquid refrigerant outlet 16 and enters the evaporator body 1. Through the heating effect of the oil recovery device 11, part of the refrigerant is vaporized and enters the suction end of the evaporator to prevent excessive liquid refrigerant from entering the compressor oil tank body 3. One end of the ejector 2 5 is connected to the high-pressure refrigerant outlet 9, one end is connected to the IGV injection oil return inlet 7, and one end is connected to the oil outlet 17. The injection oil return principle is to draw out high-pressure refrigerant gas from the high-pressure refrigerant outlet 9 of the compressor body 20. When passing through the injection nozzle, a strong suction force is generated due to the injection effect, which sucks out the mixture of oil and refrigerant from the oil recovery device 11, and after mixing with the high-pressure gas ejected from the nozzle, it is transported to the IGV injection oil return inlet 7 through the nozzle outlet pipeline. Since the pressure in the IGV is relatively low, part of the refrigerant in the oil and refrigerant mixture is vaporized.The remaining refrigerant and oil mixture flows downward with the IGV shell and flows out from the IGV injection oil return outlet 8 together with the oil gathered in the IGV into the injector 1 4. One end of the injector 1 4 is connected to the high-pressure refrigerant outlet 9, and the other end is connected to the oil return port of the oil tank body 3. A solenoid valve 6 is installed on the injector 2 5 and the evaporator body 1 injection oil return inlet pipeline. The solenoid valve 6 is opened for a period of time, and the actual time can be set by the controller according to the requirements, and then closed for a period of time to control the return oil amount of the evaporator body 1 to prevent too much liquid refrigerant from being sucked into the oil tank body 3, thereby achieving heating. Compared with the above-mentioned refrigeration oil return system, an oil recovery device 11 is added to use the high-temperature refrigerant liquid of the condenser body 12 to return the first The oil and refrigerant mixture is heated to achieve pre-separation of the oil and refrigerant. The above two oil recovery systems effectively solve the problem of lubricating oil accumulating in the oil-rich area of the evaporator body 1 and affecting the heat exchange effect. At the same time, they also prevent excessive refrigerant liquid from entering the compressor oil tank body 3. Traditional oil recovery systems are generally manual valves that do not control the return oil volume. The injection volume is fixed. This oil return system also improves the control strategy by adding a solenoid valve 6 to the return oil pipeline. By controlling the on / off state of the solenoid valve 6, the return oil volume of the evaporator is controlled, preventing excessive liquid refrigerant from being sucked into the oil tank body 3. It also solves the problem of oil leakage caused by the refrigerant vaporization and foaming due to low pressure, which brings oil into the compressor cavity.

[0039] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any other form. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes for application in other fields. However, any simple modification, equivalent change and modification of the above embodiment made according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A centrifugal unit oil return system, comprising a compressor body (20) and an evaporator body (1), characterized in that: Also includes: An oil recovery device (11) and a condenser body (12); An IGV body (2) is fixedly arranged on the outer surface of the evaporator body (1), and an IGV injection oil return inlet (7) is opened on the outer surface of the IGV body (2); An oil tank return port (10) is provided on the outer surface of the compressor body (20) near the top; A high-pressure refrigerant outlet (9) is provided on the outer surface of the compressor body (20) near the bottom, and an ejector 2 (5) is fixedly connected to the port of the high-pressure refrigerant outlet (9); Two evaporator oil return ports (13) are provided on the outer surface of the evaporator body (1), and one of the evaporator oil return ports (13) is connected to the suction port of the ejector 2 (5) through a hose; The IGV ejection oil return outlet (8) is opened on the outer surface of the IGV body (2) near the bottom, and the port of the IGV ejection oil return outlet (8) is fixedly connected to an ejector (4).

2. The centrifugal unit oil return system according to claim 1, characterized in that: The oil tank body (3) is fixedly mounted on the bottom of the compressor body (20), the other end of the ejector 2 (5) is fixedly connected to the port of the IGV ejection return oil inlet (7), and one end of the ejector 1 (4) is fixedly connected to the port of the high-pressure refrigerant outlet (9).

3. The centrifugal unit oil injection return system according to claim 1, characterized in that: The other end of the ejector 1 (4) is connected to the port of the oil return port (10) of the oil tank through a hose, and a solenoid valve (6) is provided at the inlet pipeline of the ejector 2 (5), and one end of the solenoid valve (6) is fixedly provided in the inlet pipeline of the evaporator oil return port (13).

4. The centrifugal unit oil injection return system according to claim 1, characterized in that: An oil inlet (15) is provided at the top of the oil recovery device (11) near the edge, a gas refrigerant outlet (18) is provided at the top of the oil recovery device (11) near the edge, a liquid refrigerant outlet (16) is provided on one side of the outer surface of the oil recovery device (11), and a condenser liquid outlet (14) is provided on the outer surface of the condenser body (12).

5. The centrifugal unit oil injection return system according to claim 1, characterized in that: A refrigerant liquid inlet (19) is provided on the other side of the outer surface of the oil recovery device (11), and an oil outlet (17) is provided at the bottom of the oil recovery device (11) near the edge.

6. The centrifugal unit oil injection return system according to claim 5, characterized in that: The oil outlet (17) is connected to the port of the second ejector (5) through a pipeline.

7. The centrifugal unit oil injection return system according to claim 4, characterized in that: The port of the condenser liquid outlet (14) is connected to the inside of the refrigerant liquid inlet (19) through a pipeline, and the port of the gas refrigerant outlet (18) is connected to the suction end of the compressor body (20) through a pipeline.

8. The centrifugal unit oil injection return system according to claim 4, characterized in that: The port of the liquid refrigerant outlet (16) is connected to the interior of the evaporator body (1) through a pipeline, and the port of the oil inlet (15) is connected to the port of the oil return port (13) of another evaporator through a hose.

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