A refrigeration system

Abstract

The embodiment of the application provides a refrigeration system, comprising a scroll compressor, a first condenser, a second condenser and a heat exchange device; the scroll compressor comprises a shell, a low-pressure cavity, a high-pressure cavity and an oil pool arranged in the shell; the high-pressure cavity is in communication with the oil pool; the shell is provided with a suction port, a liquid injection enthalpy-increasing port, a first exhaust port and a first oil outlet; the first exhaust port is used for being in communication with the first condenser and is used for conveying condensed refrigerant to the heat exchange device; one end of the suction port is in communication with the scroll compressor and the other end is in communication with the heat exchange device and is used for sucking the backflow refrigerant after heat exchange of the heat exchange device; the first oil outlet is in communication with the inlet of the second condenser; the outlet of the second condenser is in communication with the liquid injection enthalpy-increasing port; and the machine oil cooled by the second condenser provides cooling for the scroll compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration equipment, in particular to a refrigeration system. BACKGROUND

[0002] In industrial production, some links need to use a refrigeration system to cool the product. In the refrigeration process, due to the high-speed rotation of the scroll compressor, a large amount of heat is generated, which makes the temperature of the scroll compressor and the exhaust temperature of the scroll compressor too high. In order to ensure the normal operation of the refrigeration system, the scroll compressor and the scroll compressor exhaust need to be cooled. In the existing refrigeration system, the scroll compressor is cooled by the refrigerant flowing back in the refrigeration system, which has the problem of slow cooling process, which may cause the risk of interruption of the refrigeration system. SUMMARY

[0003] The purpose of the embodiment of the present application is to provide a refrigeration system to cool the scroll compressor and the scroll compressor exhaust, and ensure the smooth operation of the refrigeration system. The specific technical scheme is as follows:

[0004] The embodiment of the present application provides a refrigeration system, comprising a scroll compressor, a first condenser, a second condenser and a heat exchange device; the scroll compressor comprises a shell, a low-pressure cavity, a high-pressure cavity and an oil pool arranged in the shell; the high-pressure cavity is in communication with the oil pool; the shell is provided with a suction port, a liquid injection enthalpy-increasing port, a first exhaust port and a first oil outlet; the first exhaust port is used to communicate with the first condenser, and is used to deliver the condensed refrigerant to the heat exchange device; one end of the suction port is in communication with the scroll compressor, and the other end is in communication with the heat exchange device, and is used to suck the refrigerant flowing back after heat exchange in the heat exchange device; the first oil outlet is in communication with the inlet of the second condenser, and the outlet of the second condenser is in communication with the liquid injection enthalpy-increasing port, and the oil cooled by the second condenser provides cooling for the scroll compressor.

[0005] The embodiment of the present disclosure provides a refrigeration system, which comprises a scroll compressor, a first condenser, a second condenser and a heat exchange device. The low-pressure cavity, the high-pressure cavity and the oil pool of the scroll compressor are in communication with each other, and the refrigerant and the oil in the scroll compressor can circulate in the scroll compressor. During operation, the scroll compressor can suck low-temperature and low-pressure refrigerant from the system through the suction port, and compress the refrigerant in the scroll compressor, so that the low-temperature and low-pressure refrigerant gas becomes high-temperature and high-pressure refrigerant. The compressed refrigerant can be discharged through the first exhaust port and enter the first condenser, the first condenser condenses the high-temperature and high-pressure refrigerant discharged by the scroll compressor, and the condensed refrigerant enters the heat exchange device for further cooling. The refrigerant after heat exchange in the heat exchange device flows back in the refrigeration system and flows back to the scroll compressor through the suction port, so that the refrigerant circulates in the refrigeration system, and the refrigeration process can continue. During the operation of the scroll compressor, about 80% of the top of the shell of the scroll compressor is in a high-temperature and high-pressure state.

[0006] Due to the high-speed operation of the scroll compressor, a large amount of heat is generated during operation. The first oil outlet on the oil pool of the scroll compressor is in communication with the inlet of the second condenser, and the high-temperature oil in the oil pool can enter the second condenser through the first oil outlet for cooling. The low-temperature oil after cooling can cool and cool the scroll compressor. The cooling method of the scroll compressor using the cooled oil has the advantages of faster cooling speed, shorter cooling time, avoidance of the situation of too high temperature in the scroll compressor, smoother operation of the scroll compressor, prolongation of the service life of the scroll compressor, and guarantee of the normal operation of the refrigeration system. In addition, cooling the scroll compressor can also reduce the temperature of the refrigerant discharged by the scroll compressor and improve the refrigeration effect.

[0007] In addition, the refrigeration system according to the embodiment of the present application can also have the following technical features:

[0008] In some embodiments, the refrigeration system further comprises an oil separator, the oil separator is arranged between the first condenser and the scroll compressor, the oil separator is provided with a first gas inlet, a first oil inlet, a second gas outlet, a second oil outlet and a third oil outlet; the first gas outlet of the shell is communicated with the first condenser through the oil separator, the oil separator is used to receive the gas mixed with oil discharged by the scroll compressor through the first gas inlet; the second gas outlet of the oil separator is communicated with the first condenser, and is used to discharge the separated gas containing refrigerant to the first condenser, so that the first condenser condenses the gas and then transports the condensed gas to the heat exchange device for heat exchange; the first oil outlet of the shell is communicated with the first oil inlet of the oil separator, and is used to keep the liquid level in the oil pool stable; the liquid injection enthalpy increase port of the shell is communicated with the second condenser through the oil separator, and is further communicated with the second oil outlet, and is used to return the oil in the oil separator to the compressor through the liquid injection enthalpy increase port to cool the compressor; the third oil outlet is used to discharge excess oil and refrigerant gas in the oil separator to the heat exchange device; the horizontal position of the third oil outlet is higher than that of the first oil inlet and the second oil outlet of the oil separator.

[0009] In some embodiments, an electromagnetic valve is arranged between the second oil outlet and the liquid injection enthalpy increase port, and the electromagnetic valve is closed when the compressor stops working.

[0010] In some embodiments, a float switch is arranged in the oil separator, the float switch opens the third oil outlet when the liquid level in the oil separator is higher than the oil level in the oil pool, and the float switch closes the third oil outlet when the liquid level in the oil separator is equal to or lower than the oil level in the oil pool.

[0011] In some embodiments, the refrigeration system further comprises a throttling device, the throttling device is arranged between the third oil outlet and the heat exchanger at the rear stage, and the pressure difference between the oil separator and the throttling device causes excess oil and refrigerant to be discharged through the third oil outlet when the liquid level in the oil separator is higher than the oil level in the oil pool.

[0012] In some embodiments, the heat exchange device comprises N-stage heat exchangers and an evaporator, N is greater than or equal to 2, the heat exchangers are connected in series, each heat exchanger comprises a liquid inlet, a second gas inlet, a gas outlet and a liquid outlet, the liquid inlet of each adjacent two heat exchangers is communicated, the gas outlet of each adjacent two heat exchangers is communicated through a gas-liquid separator, the third oil outlet is communicated with the liquid inlet of the second heat exchanger, the liquid outlet of the Nth heat exchanger is communicated with the inlet of the evaporator, and the outlet of the evaporator is communicated with the liquid inlet of the N-1th heat exchanger.

[0013] In some embodiments, the refrigeration system further comprises a first temperature sensor and a second temperature sensor, the first temperature sensor is arranged at the gas outlet of the Nth heat exchanger; the second temperature sensor is arranged at the outlet pipeline of the evaporator; the scroll compressor is a variable frequency scroll compressor; a control system, in the pre-cooling state, the control system controls the first temperature sensor to collect the temperature of the refrigerant between the liquid inlet and the gas outlet of the Nth heat exchanger in real time, when the first temperature sensor collects the temperature reaching a first preset temperature, the control system reduces the operating frequency of the scroll compressor; in the refrigeration working state, the control system controls the second temperature sensor to collect the temperature of the refrigerant output by the evaporator in real time, when the second temperature sensor collects the temperature reaching a second preset temperature, the control system reduces the operating frequency of the scroll compressor. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other embodiments can also be obtained by those skilled in the art according to these drawings.

[0015] Figure 1 A connection schematic diagram of the refrigeration system provided by the embodiments of the present application;

[0016] Figure 2 A structure schematic diagram of the scroll compressor provided by the embodiments of the present application;

[0017] Figure 3 An oil separator structure schematic diagram provided by the embodiments of the present application;

[0018] Figure 4 An amplification schematic diagram of the heat exchanger provided by the embodiments of the present application.

[0019] The following are the signs:

[0020] Scroll compressor 10; oil separator 20; first condenser 30; heat exchange device 40; second condenser 50; shell 100; low pressure cavity 110; high pressure cavity 120; oil pool 130; suction port 111; liquid injection enthalpy-increasing port 112; first exhaust port 113; first oil outlet port 114; first air inlet port 21; second exhaust port 22; first oil inlet port 23; second oil outlet port 24; third oil outlet port 25; electromagnetic valve 60; float 210; moving plunger 220; long tube 230; first throttling device 701; second throttling device 702; third throttling device 703; filter 71; first stage heat exchanger 41; second stage heat exchanger 42; fourth stage heat exchanger 44; fifth stage heat exchanger 45; evaporator 80; second air inlet port 411; liquid outlet port 412; gas outlet port 413; liquid inlet port 414; gas-liquid separator 46; bypass 47; first temperature sensor 481; second temperature sensor 482; first pressure sensor 491; second pressure sensor 492; pressure gauge 493; buffer tank 90. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art based on the present application belong to the scope of protection of the present application.

[0022] It should be understood that the terms used herein are for the purpose of describing particular example embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.

[0023] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0024] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented, such as rotated 90 degrees or in other directions, and the spatial relative descriptors used in the text will be interpreted accordingly.

[0025] like Figures 1 to 4 As shown, this disclosure proposes a refrigeration system, including: a scroll compressor 10, a first condenser 30, a second condenser 50, and a heat exchange device 40; the scroll compressor 10 includes a housing 100 and a low-pressure chamber 110, a high-pressure chamber 120, and an oil sump 130 disposed within the housing 100; the high-pressure chamber 120 is connected to the oil sump 130; the housing 100 is provided with an air intake 111, a liquid injection enthalpy-increasing port 112, a first exhaust port 113, and a first oil outlet 114; the first exhaust port 111... 13 is used to connect with the first condenser 30 and to transport the condensed refrigerant to the heat exchange device 40. One end of the suction port 111 is connected to the scroll compressor 10 and the other end is connected to the heat exchange device 40 to draw in the refrigerant that returns after heat exchange in the heat exchange device 40. The first oil outlet 114 is connected to the inlet of the second condenser 50 and the outlet of the second condenser 50 is connected to the liquid injection enthalpy-increasing port 112. The oil cooled by the second condenser 50 provides cooling for the scroll compressor 10.

[0026] The embodiment of the present disclosure provides a refrigeration system, which comprises a scroll compressor 10, a first condenser 30, a second condenser 50 and a heat exchange device 40. The low-pressure cavity 110, the high-pressure cavity 120 and the oil pool 130 of the scroll compressor 10 are in communication with each other, and the refrigerant and the oil in the scroll compressor 10 can circulate in the scroll compressor 10. During operation, the scroll compressor 10 can suck low-temperature and low-pressure refrigerant from the system through the suction port 111, and compress the refrigerant in the scroll compressor 10, so that the low-temperature and low-pressure refrigerant gas becomes high-temperature and high-pressure refrigerant. The compressed refrigerant can be discharged through the first exhaust port 113 and enter the first condenser 30. The first condenser 30 condenses the high-temperature and high-pressure refrigerant discharged from the scroll compressor 10 according to the actual demand in the subsequent heat exchange device 40. The condensed refrigerant enters the heat exchange device 40 for further cooling. The refrigerant after heat exchange in the heat exchange device 40 flows back in the refrigeration system and flows back to the scroll compressor 10 through the suction port 111, so that the refrigerant circulates in the refrigeration system, and the refrigeration process can continue. During the operation of the scroll compressor 10, the outside of the shell 100 of the scroll compressor 10 is in a high-temperature state, and the inside of the high-pressure cavity 120 is in a high-pressure state.

[0027] Due to the high-speed operation of the scroll compressor 10, a large amount of heat is generated during operation. The first oil outlet 114 on the oil pool 130 of the scroll compressor 10 is in communication with the inlet of the second condenser 50, and the high-temperature oil in the oil pool 130 can enter the second condenser 50 through the first oil outlet 114 for cooling. The low-temperature oil after cooling can cool and cool the scroll compressor 10. Compared with using the backflow refrigerant to cool the scroll compressor 10, the cooling speed of the scroll compressor 10 using the cooled oil is faster, the required time is shorter, the situation that the temperature in the scroll compressor 10 is too high can be avoided, the scroll compressor 10 runs more stably, the service life of the scroll compressor 10 is prolonged, and the normal operation of the refrigeration system is ensured. In addition, cooling the scroll compressor 10 can also reduce the temperature of the refrigerant discharged from the scroll compressor 10, and improve the refrigeration effect.

[0028] Specifically, the present application is a single scroll compressor refrigeration system, which can realize a refrigeration temperature of-60℃ to-160℃. The scroll compressor used is a scroll compressor with a high-pressure cavity 120, and the pressure in the low-pressure cavity 110 is lower than that in the high-pressure cavity 120. Compared with the butterfly valve compressor used in the refrigeration system in the prior art, the scroll compressor can withstand greater suction force and higher exhaust temperature in the refrigeration system.

[0029] Specifically, the refrigerant, also known as coolant, is a medium substance in a refrigeration device to complete energy conversion. In a cascade refrigeration system, the refrigerant is a composite refrigerant, which is usually composed of more than five refrigerants. In the embodiments of the present application, the first refrigerant can be argon or nitrogen, the second refrigerant can be methane or krypton, the third refrigerant can be tetrafluoromethane, the fourth refrigerant can be trifluoromethane or fluoromethane, the fifth refrigerant can be hexafluoropropylene or pentafluoropropylene, and the sixth refrigerant can be chlorotrifluoropropylene or hexafluoro-2-butene. The above refrigerants are non-toxic and non-flammable, which improves the safety of the refrigeration system.

[0030] Specifically, the cooling method of the first condenser 30 can be water cooling or air cooling. Preferably, since the cooling effect of water cooling is better, in the embodiments of the present application, water is selected as the heat exchange medium of the first condenser 30. Similarly, the heat exchange medium of the second condenser 50 is also water.

[0031] Specifically, the direction of the first exhaust port 113 can be perpendicular to the direction of the longitudinal section of the scroll compressor 10 on the shell 100.

[0032] Specifically, as shown in Figure 1 , a filter 71 can be arranged between the first condenser 30 and the heat exchange device 40 to filter out impurities in the refrigerant and prevent the refrigeration pipeline from being blocked.

[0033] In some embodiments of the present application, as shown in Figure 1 , Figure 2 and Figure 3As shown, the refrigeration system further comprises an oil separator 20 arranged between the first condenser 30 and the scroll compressor 10, and the oil separator 20 is provided with a first gas inlet 21, a first oil inlet 23, a second gas outlet 22, a second oil outlet 24 and a third oil outlet 25; the first gas outlet 113 of the shell 100 is communicated with the first condenser 30 through the oil separator 20, and the oil separator 20 is used to receive the gas mixed with the refrigerant and the oil discharged by the scroll compressor 10 through the first gas inlet 21; the second gas outlet 22 of the oil separator 20 is communicated with the first condenser 30, and is used to discharge the separated gas containing the refrigerant to the first condenser 30, so that the first condenser 30 condenses the gas and then transports the gas to the heat exchange device 40 for heat exchange; the first oil outlet 114 of the shell 100 is communicated with the first oil inlet 23 of the oil separator 20, and is used to keep the liquid level in the oil pool 130 stable; the liquid injection enthalpy increase port 112 of the shell 100 is communicated with the second condenser 50 through the oil separator 20, and is further communicated with the second oil outlet 24, and is used to return the oil in the oil separator 20 to the scroll compressor 10 through the liquid injection enthalpy increase port 112 to cool the scroll compressor 10; the third oil outlet 25 is used to discharge excess oil and refrigerant gas in the oil separator 20 to the heat exchange device 40; and the horizontal position of the third oil outlet 25 is higher than that of the first oil inlet 23 and the second oil outlet 24 of the oil separator 20.

[0034] In the embodiment of the present application, the high-temperature and high-pressure refrigerant compressed by the scroll compressor 10 is discharged from the scroll compressor 10 through the first gas outlet 113 and enters the oil separator 20 through the first gas inlet 21.

[0035] During the compression process, some high-boiling-point refrigerant is liquefied and precipitated in the oil pool 130 and is mutually soluble with the oil in the scroll compressor 10. The first oil inlet 23 is communicated with the first oil outlet 114, so that the oil mixed with the high-boiling-point refrigerant in the scroll compressor 10 and the oil in the oil separator 20 can flow into each other, and the oil level in the scroll compressor 10 can be controlled to be always not lower than the oil level in the oil separator 20 by controlling the oil level in the oil separator 20, so that the risk of oil shortage of the scroll compressor 10 during operation can be avoided, the oil level of the scroll compressor 10 is stabilized, and the scroll compressor 10 runs more stably, thereby ensuring the normal operation of the refrigeration system.

[0036] Refrigerant gas containing engine oil can be separated into refrigerant gas and engine oil in the oil separator 20. The separated engine oil settles to the bottom of the oil separator 20 and mixes with the existing engine oil in the oil separator 20, and is discharged through the second oil outlet 24. Under pressure, the mixture of engine oil and high-boiling-point refrigerant in the oil separator 20 is transported to the liquid injection enthalpy-increasing port 112 of the scroll compressor 10. The gas separated in the oil separator 20 is discharged through the second exhaust port 22 and enters the first condenser 30. The gaseous refrigerant discharged from the second exhaust port 22 has a higher temperature, and the first condenser 30 can cool the refrigerant according to the actual needs of the subsequent heat exchange device 40.

[0037] Furthermore, in the vertical direction of the oil separator 20, the second oil outlet 24 of the oil separator 20 is lower than the first oil inlet 23.

[0038] During the refrigeration process, as the high-boiling-point refrigerant mixes with the engine oil and flows continuously into the oil separator 20, a portion of the high-boiling-point refrigerant cannot flow into the subsequent heat exchange device 40, thus failing to play its role. Therefore, the oil separator 20 is equipped with a third oil outlet 25, which is mainly used to discharge the high-boiling-point refrigerant in the oil separator 20 into the subsequent heat exchange device 40 to play its role.

[0039] Since the oil discharged from the scroll compressor 10 can be separated by the oil separator 20 and returned to the scroll compressor 10, the oil that has been vaporized at high temperature in the scroll compressor 10 can be condensed and returned to the scroll compressor 10 to continue to operate the scroll compressor 10. The oil discharged outside the scroll compressor 10 can be recycled and reused, thereby saving costs.

[0040] like Figure 1 and Figure 2 As shown, in some embodiments of this application, a solenoid valve 60 is provided between the second oil outlet 24 and the liquid injection enthalpy-increasing port 112. When the scroll compressor 10 stops working, the solenoid valve 60 is closed.

[0041] like Figure 1 As shown in this embodiment, the scroll compressor 10 has a liquid injection enthalpy-increasing port 112 on its housing 100. Refrigerant and oil from the oil separator 20 can enter the scroll compressor 10 through the second oil outlet 24 and the liquid injection enthalpy-increasing port 112, thus cooling the scroll compressor 10. The solenoid valve 60 between the liquid injection enthalpy-increasing port 112 and the scroll compressor 10 can cut off the pipeline entering the scroll compressor 10 from the liquid injection enthalpy-increasing port 112 after the scroll compressor 10 stops, preventing a large amount of oil at the bottom of the scroll compressor 10 from being drawn into the low-pressure chamber 110 through the liquid injection enthalpy-increasing port 112, which could cause oil shortage and damage to the scroll plate of the scroll compressor 10 when it restarts, thereby ensuring the normal operation of the refrigeration system.

[0042] In some embodiments of the present application, as shown in Figure 3 A float switch is arranged in the oil separator 20. When the liquid level in the oil separator 20 is higher than the oil level in the oil pool 130, the float switch opens the third oil outlet 25. When the liquid level in the oil separator 20 is equal to or lower than the oil level in the oil pool 130, the float switch closes the third oil outlet 25.

[0043] In the embodiments of the present application, too much oil may be deposited in the oil separator 20, causing the oil level to exceed the oil level in the oil pool 130 of the scroll compressor 10. In order to keep the oil level in the scroll compressor 10 stable and thus keep the scroll compressor 10 running smoothly, a third oil outlet 25 is arranged in the oil separator 20 to discharge excess oil in the oil separator 20, so that the oil level in the oil separator 20 is basically the same as the oil level in the oil pool 130 of the scroll compressor 10. A float switch is arranged at the third oil outlet 25. When the oil level in the oil separator 20 is too high, the float 210 floats up, opening the passage of the third oil outlet 25. When the oil level in the oil separator 20 is the same as the oil level in the scroll compressor 10, the float 210 sinks down, and the float switch blocks the third oil outlet 25. Compared with other devices for controlling the liquid level, the float switch has a relatively simple structure and low cost, and can relatively stably control the height of the oil level in the oil separator 20.

[0044] Specifically, as shown in Figure 3 The float switch is composed of a float 210, a moving pin 220, and a long tube 230. The float 210 floats on the oil surface and moves up or down according to the position of the oil surface. The moving pin 220 is in an inverted V shape, with one end of the pin blocking the lower end inlet of the long tube 230. The lower end inlet of the long tube 230 can be the third oil outlet 25. The height of the third oil outlet 25 determines the height of the liquid surface in the oil pool 130. The oil outlet of the third oil outlet 25 relies on the hydrostatic pressure between the oil pool 130 and the third oil outlet 25. When the height of the liquid surface in the oil pool 130 is equal to the height of the third oil outlet 25, there is no hydrostatic pressure, so the third oil outlet 25 stops discharging oil. Therefore, by controlling the height of the third oil outlet 25, the liquid surface in the oil pool 130 can be maintained at a constant position. The long tube 230 is fixed to the bottle body of the oil separator 20, and the moving pin 220 can move up and down in the long tube 230. The bottom end of the long tube 230 can be leveled with the first oil inlet 23 of the oil separator 20. When the oil level rises, the float 210 floats up along the moving pin 220, giving the moving pin 220 a downward force, causing the moving pin 220 to move down and away from the bottom end of the long tube 230, thus exposing the third oil outlet 25, so that the oil in the oil separator 20 can be discharged from the third oil outlet 25.

[0045] In some embodiments of the present application, as shown in Figure 1The refrigeration system also comprises a first throttling device 701 arranged between the third oil outlet 25 and the heat exchanger at the rear stage. When the liquid level in the oil separator 20 is higher than the oil level in the oil pool 130, the pressure difference between the oil separator 20 and the first throttling device 701 causes excessive oil and refrigerant to be discharged through the third oil outlet 25.

[0046] In the embodiments of the present application, the oil level in the oil separator 20 can be controlled through the first throttling device 701, thereby controlling the oil level in the scroll compressor 10. The first throttling device 701 can function as the float switch. As long as the liquid level in the oil separator 20 is higher than the third oil outlet 25, there will be a static pressure difference between the oil separator 20 and the third oil outlet 25. The static pressure difference can cause excessive oil and refrigerant to be discharged through the third oil outlet 25. As the refrigeration system continuously operates, the oil level in the oil separator 20 continuously rises, causing excessive oil and high-boiling-point liquid refrigerant to accumulate in the oil separator 20. In order to maintain the stability of the oil level in the scroll compressor 10, the excess oil and refrigerant need to be discharged. The throttling device is one of the important components in the refrigeration system. The throttling device can form a local contraction in the oil flow in the pipeline between the third oil outlet 25 and the heat exchanger at the rear stage, thereby increasing the flow rate of the oil, reducing the static pressure, and further generating a static pressure difference before and after the throttling device. Under the action of the pressure difference, the excessive oil and high-boiling-point refrigerant in the oil separator 20 are discharged through the third oil outlet 25.

[0047] Specifically, the first throttling device 701 can be a capillary tube, an electronic expansion valve, a throttling valve, or the like. Preferably, the capillary tube is used as the first throttling device 701. The capillary tube is the simplest throttling device in structure, has low manufacturing cost, and is conducive to reducing the operating cost of the entire refrigeration system. Moreover, the capillary tube has no moving parts and is not prone to failure or leakage. Therefore, the risk of oil leakage in the capillary tube can be reduced, thereby improving the stability of the operation of the refrigeration system.

[0048] It should be noted that the float switch and the first throttling device 701 can be provided simultaneously or separately.

[0049] In some embodiments of the present application, as shown in FIG. 1, Figure 1 and Figure 4As shown, the heat exchange device 40 includes N-stage heat exchangers and an evaporator 80, where N is greater than or equal to 2. The heat exchangers are connected in series. Each heat exchanger includes a liquid inlet 414, a second air inlet 411, an air outlet 413, and a liquid outlet 412. The liquid inlet 414 and air outlet 413 of each adjacent heat exchanger are connected. The liquid outlet 412 and second air inlet 411 of each adjacent heat exchanger are connected through a gas-liquid separator 46. The third oil outlet 25 is connected to the liquid inlet 414 of the second-stage heat exchanger 42. The liquid outlet 412 of the Nth-stage heat exchanger is connected to the inlet of the evaporator 80. The outlet of the evaporator 80 is connected to the liquid inlet 414 of the (N-1)th-stage heat exchanger.

[0050] In this embodiment, the more heat exchange stages in the refrigeration system, the lower the refrigeration temperature. In cryogenic water vapor replenishment pumps and some equipment requiring low-temperature refrigeration, 4-6 stage heat exchangers are commonly used. Taking a five-stage heat exchanger as an example, the evaporator 80 is one of the important components of the refrigeration system. The evaporator 80 has an inlet and an outlet. The liquid outlet 412 of the fifth-stage heat exchanger 45 is connected to the inlet of the evaporator 80. The refrigerant that has undergone five stages of heat exchange enters the evaporator 80 through the liquid outlet 412 of the fifth-stage heat exchanger 45.

[0051] like Figure 1 As shown in this embodiment, the liquid inlet 414 and gas outlet 413 of adjacent heat exchangers are connected, and the liquid outlet 412 and second gas inlet 411 of each adjacent heat exchanger are connected via a gas-liquid separator 46. For example, the liquid inlet 414 of the first-stage heat exchanger 41 is connected to the gas outlet 413 of the second-stage heat exchanger 42, and the liquid outlet 412 of the first-stage heat exchanger 41 is connected to the second gas inlet 411 of the second-stage heat exchanger 42, which enables the refrigerant to flow between the five heat exchangers. The gas-liquid separator 46 separates the mixed refrigerant flowing out of each stage heat exchanger into gas and liquid. For example, the gas and liquid mixed refrigerant flowing out of the liquid outlet 412 of the first stage heat exchanger 41 is separated by the gas-liquid separator 46. The separated gaseous refrigerant flows into the second stage heat exchanger 42 through the second inlet 411. The gaseous refrigerant releases heat in the heat exchanger, and the gaseous refrigerant with the higher boiling point in the mixed refrigerant liquefies in the heat exchanger. The liquid refrigerant separated by the gas-liquid separator 46 enters the second stage heat exchanger 42 through the liquid inlet 414.

[0052] Specifically, such as Figure 1 As shown, a filter 71 and a second throttling device 702 are also provided between the liquid flow pipeline of the gas-liquid separator 46 and the subsequent heat exchanger. The filter 71 can filter out impurities in the liquid refrigerant to prevent blockage of the refrigeration pipeline and thus prevent the refrigeration system from operating normally. The second throttling device 702 can be used to throttle and reduce pressure and regulate the flow rate.

[0053] In another embodiment, a gas-liquid separator 46 is provided between the first stage and the (N-1)th stage heat exchanger, and the gas-liquid separator 46 may not be provided between the Nth stage heat exchanger and the (N-1)th stage heat exchanger. Taking a five-stage heat exchange system as an example, a gas-liquid separator 46 is provided in each adjacent heat exchanger from the first-stage heat exchanger 41 to the fourth-stage heat exchanger 44. For example, a gas-liquid separator 46 is provided between the liquid outlet 412 of the first-stage heat exchanger 41 and the second air inlet 411 of the second-stage heat exchanger 42. A gas-liquid separator 46 is also provided between the liquid outlet 412 of the second-stage heat exchanger 42 and the second air inlet 411 of the third-stage heat exchanger. The gas and liquid refrigerant flowing out of the liquid outlet 412 of the first-stage heat exchanger 41 is separated by the gas-liquid separator 46. The separated gaseous refrigerant flows into the second-stage heat exchanger 42 from the second air inlet 411. The gaseous refrigerant releases heat in the heat exchanger, and the gaseous refrigerant with the higher boiling point in the mixed refrigerant liquefies in the heat exchanger. The liquid refrigerant separated by the gas-liquid separator 46 enters the second-stage heat exchanger 42 through the liquid inlet 414.

[0054] A gas-liquid separator 46 may not be provided between the liquid outlet 412 of the fourth-stage heat exchanger 44 and the second air inlet 411 of the fifth-stage heat exchanger 45. The fifth-stage heat exchanger 45 may include a bypass 47, one end of which is connected to the liquid inlet 414 of the fifth-stage heat exchanger 45, and the other end of which is connected to the liquid outlet 412 of the fifth-stage heat exchanger 45. A third throttling device 703 may be provided on the bypass 47.

[0055] After the refrigerant exits from the liquid outlet 412 of the fifth-stage heat exchanger 45, a portion of the refrigerant flows into the evaporator 80 through the inlet, while the other portion enters the liquid inlet 414 of the fifth-stage heat exchanger 45 through the bypass 47. The third throttling device 703 can throttle and cool the refrigerant passing through the bypass 47, so the temperature of the refrigerant flowing into the liquid inlet 414 of the fifth stage through the bypass 47 is lower than the temperature of the refrigerant at the liquid outlet 412 of the fifth-stage heat exchanger 45, thus achieving self-cooling of the fifth-stage heat exchanger 45.

[0056] like Figure 1 , Figure 2 and Figure 3 As shown, the mixture of oil and high-boiling-point liquid refrigerant in the oil separator 20 can enter the second-stage heat exchanger 42 through the third oil outlet 25, allowing the high-boiling-point refrigerant to enter the refrigeration system to dissolve the low-boiling-point refrigerant that has solidified in the system, preventing pipe blockage, and enabling the high-boiling-point refrigerant to play a refrigeration role in the heat exchanger 40.

[0057] Specifically, the heat exchangers at all levels in the system are cooled by the heat exchangers at the next level, so that a large low-temperature temperature zone can be obtained to realize self-recovery cascade refrigeration.

[0058] In some embodiments of the present application, as shown in Figure 1 and Figure 2 The refrigeration system further comprises a first temperature sensor 481 and a second temperature sensor 482, the first temperature sensor 481 is arranged at the gas outlet 413 of the Nth heat exchanger, and the second temperature sensor 482 is arranged at the outlet pipeline of the evaporator 80; the scroll compressor 10 is a variable frequency scroll compressor; the control system controls the first temperature sensor 481 to collect the temperature of the refrigerant at the gas outlet 413 of the Nth heat exchanger in real time in the pre-cooling state, and reduces the operating frequency of the scroll compressor 10 when the first temperature sensor 481 collects the temperature reaching a first preset temperature; the control system controls the second temperature sensor 482 to collect the temperature of the refrigerant output by the evaporator 80 in real time in the refrigeration working state, and reduces the operating frequency of the scroll compressor 10 when the second temperature sensor 482 collects the temperature reaching a second preset temperature.

[0059] In the embodiments of the present application, since the refrigerant continuously undergoes phase change in the heat exchange device 40, it is necessary to monitor the temperature change in the system in real time, wherein the first temperature sensor 481 is located at the gas outlet 413 of the Nth heat exchanger, and the temperature detected by the first temperature sensor 481 is the temperature of the refrigerant after N-stage heat exchange in the refrigeration system. The second temperature sensor 482 is located at the outlet of the evaporator 80, and the detected temperature is the temperature of the refrigerant after evaporation in the evaporator 80. The first temperature sensor 481 and the second temperature sensor 482 are arranged in the refrigeration system, which is beneficial for the attendant to timely understand the operation of the refrigeration system, so as to control the opening, closing or change the frequency of the scroll compressor 10.

[0060] In the embodiments of the present application, the scroll compressor 10 can be a variable frequency scroll compressor, which can change the refrigeration power by changing the frequency, and then change the refrigeration temperature according to the actual needs to meet the cooling demand in different working conditions.

[0061] Since the refrigeration system is relatively large, before external refrigeration, the entire refrigeration system needs to be cooled to below-140℃, and only when the temperature inside the entire refrigeration system reaches-140℃, the refrigeration system can output external refrigeration, and the process of cooling the refrigeration system is the pre-cooling state. The process of refrigeration system refrigeration is the working state.

[0062] Specifically, in the pre-cooling state, if the user does not output cooling, the temperature in the refrigeration system will become lower and lower. However, the pre-cooling temperature is not the lower the better. Some refrigerants in the mixed refrigerant have a freezing point above-150℃, and the low temperature in the refrigeration system can cause the refrigerant to freeze and block the pipeline, thereby causing abnormal refrigeration. In order to ensure the smooth progress of the refrigeration process, a first preset temperature is set in the control system, which can be-140℃. When the temperature detected by the first temperature sensor 481 reaches the first preset temperature, the control system can control the scroll compressor 10 to reduce the frequency, and the low pressure rises, the evaporation temperature rises, and the temperature in the refrigeration system rises, thereby preventing the refrigerant from freezing.

[0063] Taking a five-stage heat exchanger as an example, in the pre-cooling state, the first temperature sensor 481 can detect the temperature value of the outlet 413 of the fifth heat exchanger 45 in real time. When the temperature detected by the first temperature sensor 481 reaches the first preset temperature, the control system can control the scroll compressor 10 to reduce the refrigeration power, prevent the refrigerant from freezing and blocking the pipeline due to the excessively low internal temperature in the pre-cooling state, and thereby cause the refrigeration system to be unable to normally refrigerate.

[0064] Conversely, in the pre-cooling state, when the first temperature sensor 481 detects that the temperature of the outlet 413 of the Nth heat exchanger is too high, the control system can control the frequency of the compressor to increase, and the temperature in the refrigeration system will be lowered. By controlling the standby temperature of the refrigeration system to be around the first preset temperature, not only the problem of freezing of the refrigerant at low temperature is solved, but also the energy consumption of the refrigeration system during the pre-cooling process is reduced.

[0065] Similarly, in the working state of the refrigeration system, a second preset temperature is set in the control system. When the second temperature sensor 482 detects that the temperature of the outlet of the evaporator 80 reaches the second preset temperature, the control system can control the scroll compressor 10 to reduce the compression frequency. By controlling the operating frequency of the scroll compressor 10, the temperature of the refrigeration system to the outside can be controlled, and the energy consumption of the refrigeration system can be reduced.

[0066] In the embodiment of the present application, the refrigeration system further includes a plurality of pressure sensors. During the refrigeration process, since the refrigerant is constantly undergoing phase change in the heat exchange device 40, it is necessary to monitor the pressure change in the system in real time.

[0067] The pressure sensor can sense the pressure signal in the system. The number of pressure sensors can be two, wherein the first pressure sensor 491 can be arranged at the liquid outlet 412 of the fourth heat exchanger 44, and the second pressure sensor 492 can be arranged at the outlet of the evaporator 80.

[0068] The pressure sensor can be connected to the pressure gauge 493, which will then display the pressure at different locations in the system more intuitively.

[0069] In some embodiments of this application, such as Figure 1 , Figure 2 As shown, the refrigeration system also includes a buffer tank 90, which is located between the first-stage heat exchanger 41 and the N-1th-stage heat exchanger.

[0070] In this embodiment, the buffer tank 90 is used to buffer the pressure fluctuations generated during the operation of the refrigeration system, so that the refrigeration system operates more smoothly.

[0071] When refrigerant exchanges heat in a heat exchanger, the continuous phase change of different refrigerants causes pressure fluctuations in the refrigeration system, leading to instability. Adding a buffer tank 90 to the heat exchanger can stabilize the pressure in the refrigeration system and ensure the normal operation of the refrigeration process.

[0072] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A refrigeration system, characterized in that, include: Scroll compressor (10), first condenser (30), second condenser (50) and heat exchange device (40); The scroll compressor (10) includes a housing (100) and a low-pressure chamber (110), a high-pressure chamber (120), and an oil sump (130) disposed within the housing (100); the high-pressure chamber (120) is connected to the oil sump (130); The housing (100) is provided with an air intake (111), a liquid injection enthalpy-increasing port (112), a first exhaust port (113) and a first oil outlet (114); the first exhaust port (113) is used to communicate with the first condenser (30) and to transport the condensed refrigerant to the heat exchange device (40); one end of the air intake (111) is connected to the scroll compressor (10) and the other end is connected to the heat exchange device (40) and to draw in the refrigerant that returns after heat exchange in the heat exchange device (40); The first oil outlet (114) is connected to the inlet of the second condenser (50), and the outlet of the second condenser (50) is connected to the liquid injection enthalpy-increasing port (112). The oil cooled by the second condenser (50) provides cooling for the scroll compressor (10). The refrigeration system also includes an oil separator (20), which is located between the first condenser (30) and the scroll compressor (10). The oil separator (20) is provided with a first air inlet (21), a first oil inlet (23), a second exhaust port (22), a second oil outlet (24) and a third oil outlet (25). The first exhaust port (113) of the housing (100) is connected to the first condenser (30) through the oil separator (20), and the oil separator (20) is used to receive the refrigerant gas mixed with oil discharged from the scroll compressor (10) through the first air inlet (21). The second exhaust port (22) of the oil separator (20) is connected to the first condenser (30) to discharge the separated gas containing refrigerant to the first condenser (30) so that the first condenser (30) condenses the gas and then delivers it to the heat exchange device (40) for heat exchange. The first oil outlet (114) of the housing (100) is connected to the first oil inlet (23) of the oil separator (20) to maintain a stable liquid level in the oil tank (130); The liquid injection enthalpy-increasing port (112) of the housing (100) is connected to the second condenser (50) through the oil separator (20) and then to the second oil outlet (24) to return the oil in the oil separator (20) to the scroll compressor (10) through the liquid injection enthalpy-increasing port (112) to cool the scroll compressor (10); The third oil outlet (25) is used to discharge excess oil and refrigerant gas in the oil separator (20) and deliver it to the heat exchange device (40); the third oil outlet (25) is horizontally higher than the first oil inlet (23) and the second oil outlet (24) of the oil separator (20).

2. The refrigeration system according to claim 1, characterized in that, A solenoid valve (60) is provided between the second oil outlet (24) and the liquid injection enthalpy-increasing port (112). When the scroll compressor (10) stops working, the solenoid valve (60) is closed.

3. The refrigeration system according to claim 1, characterized in that, The oil separator (20) is equipped with a float switch. When the liquid level in the oil separator (20) is higher than the oil level in the oil tank (130), the float switch opens the third oil outlet (25). When the liquid level in the oil separator (20) is equal to or lower than the oil level in the oil tank (130), the float switch closes the third oil outlet (25).

4. The refrigeration system according to claim 1, characterized in that, The refrigeration system also includes a throttling device (70), which is located between the third oil outlet (25) and the subsequent heat exchanger. When the liquid level in the oil separator (20) is higher than the oil level in the oil sump (130), the pressure difference between the oil separator (20) and the throttling device (70) causes the excess oil and refrigerant to be discharged through the third oil outlet (25).

5. The refrigeration system according to any one of claims 1-4, characterized in that, The heat exchange device (40) includes N-stage heat exchangers and an evaporator (80), where N is greater than or equal to 2. The heat exchangers at each stage are connected in series. Each stage of the heat exchanger includes a liquid inlet (414), a second air inlet (411), an air outlet (413), and a liquid outlet (412). The liquid inlet (414) and the air outlet (413) between any two adjacent stages of the heat exchanger are connected. The liquid outlet (412) and the second air inlet (411) between any two adjacent stages of the heat exchanger are connected through a gas-liquid separator (46). The third oil outlet (25) is connected to the liquid inlet (414) of the second stage heat exchanger (42) via a pipeline. The liquid outlet (412) of the Nth stage heat exchanger is connected to the inlet of the evaporator (80). The outlet of the evaporator (80) is connected to the liquid inlet (414) of the N-1th stage heat exchanger.

6. The refrigeration system according to claim 5, characterized in that, The refrigeration system also includes a first temperature sensor (481) and a second temperature sensor (482). The first temperature sensor (481) is located at the outlet (413) of the Nth stage heat exchanger; the second temperature sensor (482) is located in the outlet pipe of the evaporator (80). The scroll compressor (10) is a variable frequency scroll compressor (10). The control system, in the pre-cooling state, controls the first temperature sensor (481) to collect the temperature of the refrigerant between the liquid inlet (414) and the gas outlet (413) in the Nth stage heat exchanger in real time. When the first temperature sensor (481) collects the temperature and it reaches the first preset temperature, the control system reduces the operating frequency of the scroll compressor (10). In the refrigeration working state, the control system controls the second temperature sensor (482) to collect the temperature of the refrigerant output by the evaporator (80) in real time. When the second temperature sensor (482) collects the temperature and it reaches the second preset temperature, the control system reduces the operating frequency of the scroll compressor (10).

Images