Refrigeration system

Abstract

The invention relates to the technical field of refrigeration, in particular to a refrigeration system. The refrigerating system comprises a compressor, an oil separator and an evaporator, an inlet of the oil separator is communicated with an outlet of the compressor, and the oil separator is provided with a refrigerant gas outlet and a mixture outlet; an inlet of the evaporator is communicated with a refrigerant gas outlet of the oil separator, and an outlet is communicated with an inlet of the compressor; the refrigerating system is further provided with a degassing device, an input pipeline and a first output pipeline, and the degassing device is communicated with the mixture outlet of the oil separator through the input pipeline and communicated with the inlet of the compressor through the first output pipeline. According to the refrigerating system, the viscosity of circulating lubricating oil in the system can be reduced while efficient oil-gas separation is achieved, the lubricating effect is improved, and the service life of equipment such as a compressor is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration, and particularly to a refrigeration system. Background Art

[0002] In a refrigeration system, after the refrigerant flows through the compressor, it is in a high-temperature and high-pressure state, and when discharged, the flow rate is fast and the temperature is high. The lubricating oil in the compressor will inevitably be mixed with the refrigerant gas in the form of oil vapor or particles under the action of high temperature. In the prior art, an oil separator is provided on the output side of the compressor to separate the lubricating oil from the refrigerant gas.

[0003] However, in the prior art, in some refrigeration systems, the temperature on the evaporator side can reach about 60°C, and the temperature on the condenser side can reach 90°C or higher. According to the current design of the oil separator system, high temperature and high pressure will cause a large amount of refrigerant to dissolve in the lubricating oil, resulting in a decrease in the viscosity of the lubricating oil, which may lead to increased wear of the equipment components in the compressor, shorten its service life, and even cause damage to components such as bearings in the compressor. Summary of the Invention

[0004] In view of the above problems, the present application provides a refrigeration system that can achieve efficient oil-gas separation while increasing the viscosity of the oil, improving the lubrication effect and the service life of equipment such as compressors.

[0005] In the technical solution of the present application, a refrigeration system is provided, which includes a compressor, an oil separator and an evaporator. The inlet of the oil separator is connected to the outlet of the compressor, and the oil separator also has a refrigerant gas outlet and a mixture outlet; the inlet of the evaporator is connected to the refrigerant gas outlet of the oil separator, and the outlet is connected to the inlet of the compressor; the refrigeration system also has a degassing device, an input pipeline and a first output pipeline. The degassing device is connected to the mixture outlet of the oil separator via the input pipeline and is connected to the inlet of the compressor via the first output pipeline.

[0006] Optionally, in the technical solution of the present application, a first throttle valve is provided on the input pipeline, and a second throttle valve is provided on the first output pipeline.

[0007] Optionally, in the technical solution of the present application, the degassing device includes a degassing container and a heater provided in the degassing container.

[0008] Optionally, in the technical solution of the present application, the refrigeration system further includes a second output pipeline, one end of which is connected to the bottom of the degassing container and the other end is connected to a downstream device.

[0009] Optionally, in the technical solution of the present application, the first throttle valve adjusts the flow rate in the input pipeline, and the second throttle valve adjusts the flow rate in the first output pipeline, so that the pressure in the degassing container is greater than the pressure in the first output pipeline.

[0010] Optionally, in the technical solution of the present application, the first throttle valve adjusts the flow rate in the input pipeline, and the second throttle valve adjusts the flow rate in the first output pipeline, so that the pressure P in the degassing container m , the pressure P in the first output pipeline s and the pressure P in the input pipeline d satisfy the following relationship: P m = P s + n * (P d - P s ), where n ∈ [0.1, 0.5].

[0011] Optionally, in the technical solution of the present application, the degassing device further includes an oil level sensor disposed in the degassing container, a pressure sensor for measuring the pressure in the degassing container, and a temperature sensor for measuring the oil temperature in the degassing container.

[0012] Optionally, in the technical solution of the present application, the first output pipeline is connected to the outlet of the evaporator.

[0013] Optionally, in the technical solution of the present application, the first throttle valve and the second throttle valve act in response to any detection result of the oil level sensor, the pressure sensor, and the temperature sensor.

[0014] In the technical solution of the present application, the compressor in the refrigeration system discharges the refrigerant mixed with lubricating oil. The oil and refrigerant mixture separated by the oil separator enters the degassing device for degassing. The refrigerant gas obtained by separating and degassing again in the degassing device and the refrigerant gas separated by the oil separator finally enter the evaporator in the same way, and then are sucked into the compressor again for compression. In the cycle process of the refrigerant in the above refrigeration system. On the other hand, the degassing device separates the refrigerant in the oil and refrigerant mixture, reduces the refrigerant content in the lubricating oil, increases the viscosity of the lubricating oil, thereby effectively improving the lubrication effect, reducing the wear during the operation of the compressor, and extending the service life of the compressor. More importantly, the oil and refrigerant mixture is at high temperature and high pressure before entering the condenser. Therefore, the temperature of the refrigerant separated in the degassing device is relatively high. When returning to the inlet of the compressor / the outlet of the evaporator, it is higher than the refrigerant coming out of the evaporator. As a result, the overall temperature of the refrigerant at the inlet of the compressor / the outlet of the evaporator becomes higher, increasing the superheat degree, and avoiding the refrigerant entering the compressor in a liquid state due to insufficient superheat degree, causing liquid hammer. Description of the Drawings

[0015] Figure 1It is a schematic diagram of the principle of a refrigeration system.

[0016] Figure 2 It is a schematic diagram of a refrigeration system in the prior art.

[0017] Figure 3 It is a schematic diagram of a refrigeration system provided in an embodiment of the present invention.

[0018] Figure 4 It is a schematic connection diagram of a degassing device provided in an embodiment of the present application.

[0019] Explanation of reference numerals: 100 - refrigeration system, 101 - compressor, 102 - condenser, 103 - expansion valve, 104 - evaporator, 105 - oil separator, 1 - degassing device, 10 - degassing container, 11 - heater, 12 - oil level sensor, 13 - pressure sensor, 14 - temperature sensor, 2 - input pipeline, 3 - first output pipeline, 4 - first throttle valve, 5 - second throttle valve, 6 - second output pipeline, compressor inlet A1, compressor outlet A2, compressor lubricating oil inlet A3, evaporator inlet B1, evaporator outlet B2, oil separator inlet C1, oil separator refrigerant gas outlet C2, oil separator mixture outlet C3. Detailed implementation manners

[0020] First of all, it should be noted that the following will illustrate the composition, working principle, characteristics, advantages, etc. of the refrigeration system according to the present application by way of examples. However, it should be understood that all the descriptions are only given for the purpose of illustration, and thus should not be construed as any limitation to the present application.

[0021] In addition, for any single technical feature described or implied in the embodiments mentioned in this article, or any single technical feature shown or implied in each drawing, the present application still allows any combination or deletion to continue between these technical features (or their equivalents) without any technical obstacles, thereby obtaining more other embodiments of the present application that may not be directly mentioned in this article.

[0022] Figure 1 It is a schematic diagram of the principle of a refrigeration system.

[0023] As Figure 1 shown, the refrigeration system 100 includes a compressor 101, a condenser 102, an expansion valve 103, and an evaporator 104 connected in sequence.

[0024] In the refrigeration / heat cycle of the refrigeration system 100, first, a compression step is carried out. The compressor 101 sucks in the refrigerant gas in the evaporator 104 and compresses and boosts it to obtain a high-temperature and high-pressure refrigerant gas.

[0025] Then comes the condensation step. The high-pressure and high-temperature refrigerant gas input into the compressor 101 exchanges heat in the condenser 102, raising the temperature of the cooling water in the condenser 102 while the refrigerant gas is condensed into a refrigerant liquid.

[0026] Next is the expansion step. The high-temperature and high-pressure refrigerant liquid in the condenser 102 flows through the expansion valve 103 for throttling expansion, reducing its pressure and temperature.

[0027] Finally is the evaporation step. The evaporator 104 evaporates the low-pressure and low-temperature refrigerant liquid into a gas, while reducing the temperature of the heat exchange medium in the evaporator 104 to achieve the refrigeration effect. The refrigerant gas in the evaporator 104 is inhaled by the compressor 101 again for compression, repeating the above cycle of compression, condensation, throttling, and evaporation.

[0028] The compressor 101 in the above refrigeration system 100 is configured as a screw compressor. The working principle of the screw compressor is that the driving rotor drives the driven rotor to rotate at a high speed. During the meshing process of the rotors, they do not contact each other. By the high-speed rotation of a pair of screws with a certain gap, the purpose of sealing and compressing the gas is achieved. And usually, lubricating oil needs to be sprayed between the screws. The lubricating oil forms an oil film between the rotors, playing the roles of sealing, lubricating, and cooling.

[0029] When the refrigerant gas is compressed in the above compressor 101, it will come into contact with the lubricating oil sprayed in the compressor 101. At this time, the refrigerant gas is compressed to a high-temperature and high-pressure state. The lubricating oil in the compressor 101 will inevitably be discharged in the form of oil vapor or particles mixed with the refrigerant gas due to the high temperature. When the refrigerant gas mixed with oil undergoes subsequent refrigeration cycles, the oil in the refrigerant gas will adhere to various parts of the refrigeration cycle pipeline, affecting the overall heat exchange efficiency of the refrigeration system 100. Moreover, as the lubricating oil in the compressor 101 is continuously discharged with the refrigerant, the lubrication effect between the screw, bearing and other components in the compressor 101 will also be affected, resulting in an increase in the friction and collision between the screw, bearing and other components in the compressor 101, reducing the working efficiency and service life of the compressor 101.

[0030] Figure 2 It is a schematic diagram of a refrigeration system in the prior art.

[0031] As Figure 2 shown, in the prior art, an oil separator 105 is provided on the output side of the compressor 101 to separate the lubricating oil mixed in the refrigerant gas. The refrigerant gas separated in the oil separator 105 flows to the condenser 102, the expansion valve 103 and the evaporator 104 to continue the refrigeration cycle of the refrigeration system 100. The lubricating oil separated in the oil separator 105 is returned to the compressor 101 for lubrication. Figure 2The solid line represents the refrigerant flow path, and the dashed line represents the oil and refrigerant mixture / lubricating oil flow path.

[0032] However, in the above-mentioned prior art solutions, it is inevitable that a small amount of lubricating oil is contained in the refrigerant gas separated in the oil separator 105. Moreover, the lubricating oil separated in the oil separator 105 has a relatively high temperature. Since the viscosity of the lubricating oil decreases as the temperature rises, the lubricating oil with too low viscosity causes insufficient lubrication, and the friction between components such as the screw and bearing in the compressor 101 increases, which is not conducive to the normal operation of the compressor 101.

[0033] According to the working principle of the refrigeration system 100 and the problems faced in its refrigeration cycle, in an embodiment of the present application, a refrigeration system 100 is provided.

[0034] Figure 3 It is a schematic diagram of a refrigeration system provided in an embodiment of the present application.

[0035] As Figure 3 shown, the refrigeration system 100 provided in this embodiment includes a compressor 101, an oil separator 105, and an evaporator 104. The compressor 101 is provided with an inlet A1 and an outlet A2; the evaporator 104 is provided with an inlet B1 and an outlet B2; the oil separator 105 is provided with an inlet C1, a refrigerant gas outlet C2, and a mixture outlet C3.

[0036] The inlet A1 of the compressor 101 is communicated with the outlet B2 of the evaporator 104; the outlet A2 of the compressor 101 is connected to the inlet C1 of the oil separator 105. The inlet B1 of the evaporator 104 is indirectly communicated with the refrigerant gas outlet C2 of the oil separator 105.

[0037] The inlet C1 of the oil separator 105 is communicated with the outlet A2 of the compressor 101, receives the high-temperature and high-pressure refrigerant gas mixed with lubricating oil discharged from the compressor 101, and performs oil-gas separation on it. The refrigerant gas outlet C2 of the oil separator 105 returns the separated refrigerant gas to the cycle of the refrigeration system 100, and it can flow through the condenser 102, the expansion valve 103, and the evaporator 104 in sequence. The mixture outlet C3 of the oil separator 105 is used to discharge the separated oil and refrigerant mixture.

[0038] Figure 4 It is a connection schematic diagram of a degassing device provided in an embodiment of the present application.

[0039] As Figure 3 and 4As shown, the refrigeration system 100 further includes a degassing device 1, an input pipeline 2, and a first output pipeline 3. The degassing device 1 is used to separate the oil and refrigerant mixture. The input pipeline 2 is connected to the mixture outlet C3 of the oil separator 105 and the degassing device 1, and is used to input the oil and refrigerant mixture into the degassing device 1. The first output pipeline 3 is connected to the degassing device 1 and the inlet A1 of the compressor 101 / the outlet B2 of the evaporator 104, and is used to output the refrigerant gas degassed in the degassing device 1.

[0040] In an embodiment of the present application, the refrigerant gas mixed with lubricating oil discharged from the outlet A2 of the compressor 101 first passes through the oil separator 105 to separate the refrigerant gas, the oil and refrigerant mixture. The refrigerant gas returns to the refrigeration system 100 for further circulation; the oil and refrigerant mixture enters the degassing device 1 through the input pipeline 2 for degassing. The refrigerant gas separated again by the degassing device 1 returns to the inlet A1 of the compressor 101 / the outlet B2 of the evaporator 104 through the first output pipeline 3, and is then sucked into the compressor 101 again for compression. During the circulation process of the refrigerant gas in the refrigeration system 100, the degassing device 1 separates the refrigerant in the oil and refrigerant mixture, reduces the content of the refrigerant in the lubricating oil, can increase the viscosity of the lubricating oil, thereby effectively improving the lubrication effect, reducing the wear during the operation of the compressor 101, and extending the service life of the compressor 101. More importantly, the oil and refrigerant mixture is at high temperature and high pressure before entering the condenser 102, and the temperature of the refrigerant separated in the degassing device 1 is relatively high. When it returns to the inlet A1 of the compressor 101 / the outlet B2 of the evaporator 104, it is higher than the refrigerant coming out of the evaporator 104. As a result, the overall temperature of the refrigerant at the inlet A1 of the compressor 101 / the outlet B2 of the evaporator 104 becomes higher, increasing the superheat degree, and avoiding the liquid refrigerant from entering the compressor 101 due to insufficient superheat degree and causing liquid hammer.

[0041] Reference Figure 4 Referring to, in an embodiment of the present application, the degassing device 1 includes a degassing container 10 and a heater 11 disposed in the degassing container 10. The degassing container 10 is used to accommodate the refrigerant gas, lubricating oil, and the oil and refrigerant mixture. The heater 11 is disposed at the bottom of the degassing container 10 and is used to heat the oil and refrigerant mixture. The input pipeline 2 is connected to the degassing container 10 from one end of the upper side surface of the degassing container 10 to input the oil and refrigerant mixture into the degassing container 10; the first output pipeline 3 is connected to the degassing container 10 from the other end of the upper side surface of the degassing container 10 to discharge the refrigerant gas from the degassing container 10.

[0042] In this embodiment, the refrigeration system 100 further includes a first throttle valve 4 and a second throttle valve 5. The first throttle valve 4 is disposed on the input pipeline 2, and the second throttle valve 5 is disposed on the first output pipeline 3.

[0043] When the degassing device 1 performs degassing, a high-temperature and high-pressure oil and refrigerant mixture is discharged from the mixture outlet C3 of the oil separator 105 and flows into the degassing device 1 through the input pipeline 2. The first throttle valve 4 on the input pipeline 2 throttles it, and the high-temperature and high-pressure oil and refrigerant mixture undergoes pressure reduction and expansion, and part of the refrigerant gas in the oil and refrigerant mixture escapes and enters the degassing container 10, and is discharged from the degassing container 10 through the first output pipeline 3. The remaining liquid oil and refrigerant mixture flows along the input pipeline 2 into the bottom of the degassing container 10. The heater 11 at the bottom of the degassing container 10 heats the liquid oil and refrigerant mixture to vaporize the refrigerant in the liquid oil and refrigerant mixture, and the obtained refrigerant gas is also discharged from the degassing container 10 through the first output pipeline 3.

[0044] Optionally, in the embodiment of the present application, the first throttle valve 4 can be used to adjust the flow rate of the oil and refrigerant mixture in the input pipeline 2; the second throttle valve 5 adjusts the flow rate of the refrigerant gas in the first output pipeline 3. In other words, the inlet gas flow rate and the outlet gas flow rate of the degassing device 1 can be respectively adjusted through the first throttle valve 4 and the second throttle valve 5, so as to adjust the gas volume and gas pressure in the degassing device 1. Specifically, by adjusting the first throttle valve 4 and the second throttle valve 5 so that the inlet gas flow rate of the degassing device 1 is greater than the outlet gas flow rate, the gas volume in the degassing device 1 will gradually increase, and similarly the gas pressure P in the degassing device 1 m will also gradually increase; conversely, by adjusting the first throttle valve 4 and the second throttle valve 5 so that the inlet gas flow rate of the degassing device 1 is less than the outlet gas flow rate, the gas volume in the degassing device 1 will gradually decrease, and similarly the gas pressure P in the degassing device 1 m will also gradually decrease.

[0045] In the embodiment of the present application, the degassing device 1 combines the methods of throttling and decompression and heating and vaporization, so that most of the refrigerant in the oil and refrigerant mixture can be degassed and discharged. And the above-mentioned degassing device 1 has low cost, simple structure and is convenient for miniaturization design, and can be applied to various refrigeration systems for oil-gas separation.

[0046] In the practical application of the present application, the first throttle valve 4 and the second throttle valve 5 can be set as capillary tubes, thermostatic expansion valves, electronic expansion valves, etc. There is no limitation here.

[0047] Reference Figure 4 In the embodiment of the present application, the refrigeration system 100 further includes a second output pipeline 6. One end of the second output pipeline 6 is connected to the bottom of the degassing container 10, and the other end is connected to the lubricating oil inlet A3 of the compressor 101. The second output pipeline 6 is used to return the lubricating oil separated by the degassing device 1 to the compressor 101.

[0048] In an embodiment of the present application, by combining throttling and decompression with heating and vaporization, most of the refrigerant in the oil and refrigerant mixture can be degassed and discharged, and the lubricating oil after exhaust is cooled, so as to obtain lubricating oil with less impurities and high viscosity and return it to the compressor 101.

[0049] Optionally, in an embodiment of the present application, the degassing device 1 further includes one or more oil level sensors 12, pressure sensors 13, and temperature sensors 14 provided in the degassing container 10. The first throttle valve 4 and the second throttle valve 5 act in response to any detection result of the oil level sensor 12, pressure sensor 13, and temperature sensor 14.

[0050] The oil level sensor 12 detects the liquid level height of the liquid oil and refrigerant mixture ( Figure 4 shown by the center dash line) in the degassing container 10, so that the liquid level height of the liquid oil and refrigerant mixture does not exceed or is maintained at the preset height of the oil level sensor 12. In the degassing container 10, the volume of the part below the liquid level height of the liquid oil and refrigerant mixture is the current liquid volume of the degassing container 10, and the volume of the part above the liquid level height is the current gas volume of the degassing container 10, so that the current liquid volume and gas volume accommodated in the degassing container 10 can be controlled by the setting and detection of the oil level sensor 12.

[0051] The first throttle valve 4 and the second throttle valve 5 can act in response to the detection result of the oil level sensor 12. For example, when the oil level sensor 12 detects that the liquid level height of the liquid oil and refrigerant mixture in the degassing container 10 is higher than the preset height of the oil level sensor 12, the flow rate of the first throttle valve 4 can be reduced and / or the flow rate of the second throttle valve 5 can be increased to reduce the liquid oil and refrigerant mixture in the degassing container 10.

[0052] Optionally, the preset height of the oil level sensor 12 is lower than the input pipeline 2, so as to prevent the outlet of the input pipeline 2 from being submerged by the liquid oil and refrigerant mixture, and facilitate the direct discharge of the refrigerant gas separated by expansion in the input pipeline 2 from the first output pipeline 3.

[0053] The pressure sensor 13 measures and feeds back the pressure in the degassing container 10. The first throttle valve 4 and the second throttle valve 5 can act in response to the detection result of the oil level sensor 12 to make the pressure P m in the degassing container 10 stable at a fixed value or within a fixed range. For example, when the pressure P m in the degassing container 10 is lower than the preset pressure of the pressure sensor 13, the flow rate of the first throttle valve 4 can be increased and / or the flow rate of the second throttle valve 5 can be reduced to increase the gas amount in the degassing container 10 and the pressure P m .

[0054] Optionally, in an embodiment of the present application, the first throttle valve 4 and the second throttle valve 5 are adjusted so that the pressure P in the degassing container 10 m , the pressure P in the first output pipeline 3 s and the pressure P in the input pipeline 2 d satisfy the following relationship: P m = P s + n * (P d - P s ), where n ∈ [0.1, 0.5], to ensure stable circulation within the entire degassing device 1.

[0055] The temperature sensor 14 measures and feeds back the oil temperature in the degassing container 10. The heater 11 can act in response to the detection result of the temperature sensor 14 to keep the oil temperature in the degassing container 10 stable at a fixed value or within a fixed range. For example, when the oil temperature in the degassing container 10 is lower than the preset temperature of the temperature sensor 14, the heating efficiency of the heater 11 can be increased to raise the oil temperature in the degassing container 10.

[0056] Optionally, in an embodiment of the present application, the heater 11 is adjusted in response to the detection result of the temperature sensor 14 so that the oil temperature in the degassing container 10 is maintained at 40 - 60K.

[0057] Optionally, in an embodiment of the present application, the degassing device 1 can also comprehensively adjust the first throttle valve 4, the second throttle valve 5 and the heater 11 according to the detection results of the oil level sensor 12, the pressure sensor 13 and the temperature sensor 14 to ensure stable circulation within the entire degassing device 1.

[0058] So far, the technical solution of the present invention has been described in conjunction with the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to the above specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. A refrigeration system, comprising: a compressor, an oil separator, the inlet of which is communicated with the outlet of the compressor, and which has a refrigerant gas outlet and a mixture outlet; an evaporator, the inlet of which is communicated with the refrigerant gas outlet of the oil separator, and the outlet of which is communicated with the inlet of the compressor; characterized in that it further has a degassing device, an input pipeline and a first output pipeline, the degassing device is communicated with the mixture outlet of the oil separator via the input pipeline and is communicated with the inlet of the compressor via the first output pipeline.

2. The refrigeration system according to claim 1, wherein A first throttle valve is provided on the input pipeline, and a second throttle valve is provided on the first output pipeline.

3. The refrigeration system according to claim 1, characterized in that, The degassing device includes a degassing container and a heater provided in the degassing container.

4. The refrigeration system according to any one of claims 1-3, characterized in that, It further includes a second output pipeline, one end of the second output pipeline is connected to the bottom of the degassing container, and the other end is connected to the compressor.

5. The refrigeration system according to claim 2 or 3, characterized in that, The first throttle valve adjusts the flow rate in the input pipeline, and the second throttle valve adjusts the flow rate in the first output pipeline, so that the pressure in the degassing container is greater than the pressure in the first output pipeline.

6. The refrigeration system according to claim 5, characterized in that, The first throttle valve adjusts the flow rate in the input pipeline, and the second throttle valve adjusts the flow rate in the first output pipeline, so that the pressure P in the degassing container m , the pressure P in the first output pipeline s and the pressure P in the input pipeline d satisfy the following relationship: P m = P s + n * (P d - P s ), Wherein, n ∈ [0.1, 0.5].

7. The refrigeration system according to claim 5, wherein, The degassing device further includes an oil level sensor provided in the degassing container, a pressure sensor for measuring the pressure in the degassing container, and a temperature sensor for measuring the oil temperature in the degassing container.

8. The refrigeration system according to any one of claims 1-3, 6-7, characterized in that, The first output pipeline is connected to the outlet of the evaporator.

9. The refrigeration system according to claim 2, characterized in that, The first throttle valve and the second throttle valve act in response to any detection results of the oil level sensor, the pressure sensor and the temperature sensor.

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