Separation system for pre-injection of CO2 refrigerating unit

Abstract

The invention relates to a separation system for pre-injection of a CO2 refrigerating unit, which relates to the technical field of separators and comprises a medium-temperature compressor, an oil separator, an air cooler, a heat exchanger, a separator, a pressure regulating valve, an ejector, a flash tank, a low-temperature evaporator, a medium-temperature evaporator and a low-temperature compressor. A refrigerant inlet is formed in the outer wall of the separator barrel, an impact plate is arranged at the position, corresponding to the refrigerant inlet, in the separator barrel, an upper-layer flow guide plate is arranged above the impact plate, and a gas refrigerant outlet is formed in the upper portion of the separator barrel; a lower-layer guide plate is arranged below the impact plate; and a liquid refrigerant outlet is formed below the lower-layer guide plate. The separator is additionally arranged in front of the ejector, gas and liquid of a high-pressure section can be separated on the premise of not losing any system energy efficiency, a refrigerant entering a high-pressure gas inlet of the ejector is made to be in a gas state, the efficiency of the ejector is guaranteed, and therefore the energy efficiency of the system is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of separators, and in particular to a separation system for a CO2 refrigeration unit injection front. Background Art

[0002] Freon is widely used as a man-made refrigerant in household appliances and industrial processes. If it spreads into the atmosphere, it will damage the ozone layer. The world is looking for green and environmentally friendly refrigerants. In the long run, CO2 refrigerant is in line with the development trend of green and environmentally friendly natural refrigerants. When using CO2 refrigeration systems, energy efficiency is an inevitable topic. After several generations of technological updates, the use of ejectors has further improved the energy efficiency of CO2 refrigeration units. In the carbon dioxide refrigeration system, the fluid cooled by the air cooler is usually a gas-liquid two-phase mixture. If it enters the ejector directly, the gas-liquid two-phase fluid will affect the working efficiency of the ejector and may even cause the ejector to fail. The use characteristic of the ejector is that the high-pressure inlet needs to be high-pressure gas. If there is liquid mixed in, it will affect the ejection effect. However, there is no separation system set up before the ejector in the current refrigeration system in the industry. Therefore, it is necessary to design a separation system that can separate the gas and liquid before the ejector to ensure that the gas enters the ejector. Summary of the invention

[0003] According to the technical problems raised above, a separation system for the pre-ejector of a CO2 refrigeration unit is provided. The present invention uses the high-pressure section of the CO2 refrigeration unit, and the separator is located between the outlet of the air cooler and the inlet of the ejector. The liquid in the gas-liquid two-phase refrigerant cooled by the air cooler is prevented from entering the high-pressure inlet of the ejector, which causes the ejector effect to decrease.

[0004] The technical means adopted by the present invention are as follows: A separation system for a CO2 refrigeration unit ejector front, comprising a medium-temperature compressor, an oil separator, an air cooler, a heat exchanger, a separator, a pressure regulating valve, an ejector, a flash tank, a low-temperature evaporator, a medium-temperature evaporator and a low-temperature compressor, wherein the output end of the medium-temperature compressor is connected to the oil separator, the output end of the oil separator is connected to the air cooler, the output end of the air cooler is connected to the first inlet of the heat exchanger, the first outlet of the heat exchanger is connected to the inlet of the separator, the separator is used to separate the refrigerant into gas and liquid, the gas output end of the separator is connected to the ejector, the liquid output end of the separator is connected to the flash tank, the output end of the ejector is connected to the flash tank, the flash tank comprises a gas outlet and a liquid outlet, wherein the gas outlet is connected to the second inlet of the heat exchanger, the second outlet of the heat exchanger is connected to the medium-temperature compressor; the liquid outlet of the flash tank is respectively connected to the low-temperature evaporator and the medium-temperature evaporator, the refrigerant enters the low-temperature compressor after passing through the low-temperature evaporator, is mixed with the refrigerant passing through the medium-temperature evaporator, and enters the medium-pressure gas inlet of the ejector.

[0005] Furthermore, the separator includes a separator cylinder, a refrigerant inlet is provided on the outer wall of the separator cylinder, an impact plate is provided at a position corresponding to the refrigerant inlet in the separator cylinder, an upper guide plate is provided above the impact plate, a gas refrigerant outlet is provided above the separator cylinder; a lower guide plate is provided below the impact plate; and a liquid refrigerant outlet is provided below the lower guide plate.

[0006] Furthermore, a separator upper end cover is arranged above the separator cylinder, and a separator lower end cover is arranged below the separator cylinder, the gas refrigerant outlet is arranged on the separator upper end cover, and the liquid refrigerant outlet is arranged on the separator lower end cover.

[0007] Further, the impact plate is arranged vertically, and a plurality of groups of auxiliary guide plates are arranged on the side of the impact plate facing the refrigerant inlet, and the auxiliary guide plates are arranged in a herringbone shape. Specifically, each group of auxiliary guide plates forms a herringbone structure, and the two auxiliary guide plates on the left and right of each group are staggered in the height direction, and the cross section formed by all the auxiliary guide plates can completely cover the projection shape of the refrigerant inlet on the impact plate; The back side of the impact plate is connected with a middle-layer guide plate, and the middle-layer guide plate is welded to the inner side of the separator cylinder.

[0008] Furthermore, the middle guide plate is a circular plate with evenly distributed through holes, and the sum of the cross-sectional areas of all the through holes must be larger than the cross-sectional area of ​​the refrigerant inlet. The middle guide plate not only has the functions of guiding and separating, but also serves as a back support and reinforcement for the impact plate.

[0009] Furthermore, the lower guide plate is a circular plate with a notch, the outer diameter of which matches the inner diameter of the separator cylinder, which is welded to the inner side of the separator cylinder, and the notch is arranged on the outer circumferential surface of the circular plate, for guiding the refrigerant. Thus, the liquid refrigerant flows into the lower layer and enters the system through the liquid refrigerant outlet pipe. At the same time, another key function of setting the lower guide plate is to guide the gas refrigerant from above to the middle and upper guide plates of the upper layer, thereby avoiding the impact of the high-pressure gas refrigerant on the liquid refrigerant surface of the lower layer, resulting in the instability of the liquid surface and affecting the monitoring data of the liquid level sensor.

[0010] Furthermore, the upper guide plate is a circular plate, on which evenly distributed through holes are opened, and the sum of the cross-sectional areas of all the through holes needs to be larger than the cross-sectional area of ​​the refrigerant inlet.

[0011] Furthermore, the positions of the circular holes of the upper guide plate and the middle guide plate are all staggered without overlap.

[0012] Furthermore, a filter screen is provided between the upper guide plate and the upper end cover of the separator. The filter screen is made of stainless steel, and the height of the stainless steel filter screen is usually about 100 mm, and the mesh number of the filter screen is usually about 100 to 150 meshes. The height and mesh number of the filter screen can also be adjusted according to different working conditions.

[0013] Furthermore, the separator fixing piece is arranged outside the separator cylinder and is welded to the separator cylinder. The size and quantity of the separator fixing piece can be adjusted according to different working conditions.

[0014] Compared with the prior art, the present invention has the following advantages: the present invention adds a separator in front of the ejector, and the refrigerant enters the separator through the refrigerant inlet and flows directly to the impact plate, so that the liquid naturally falls through the gaps around the lower guide plate, flows into the lower end cover of the separator, and enters the pressure regulating valve through the liquid refrigerant outlet. The gas refrigerant passes through the lower guide plate, the middle guide plate and the upper guide plate, through the filter screen, and enters the ejector from the gas refrigerant outlet. Thereby, the gas and liquid in the refrigerant from the air cooler are separated, so that what enters the ejector is gas refrigerant, which ensures the efficiency of the ejector. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 Schematic diagram of the system of the present invention.

[0017] Figure 2 It is a schematic diagram of the external structure of the separator of the present invention.

[0018] Figure 3 It is a structural explosion diagram of the present invention.

[0019] In the figure: 1. medium temperature compressor, 2. oil separator, 3. air cooler, 4. parallel heat exchanger, 5. separator, 6. pressure regulating valve, 7. ejector, 8. flash tank, 9. low temperature evaporator, 10. medium temperature evaporator, 11. low temperature compressor, 51. separator cylinder, 52 separator upper end cover, 53. filter screen, 54. upper guide plate, 55. refrigerant inlet, 56. impact plate, 57. lower guide plate, 58. liquid level sensor interface, 59. gas refrigerant outlet, 510. middle guide plate, 511. separator fixing, 512. separator lower end cover, 513. liquid refrigerant outlet. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0024] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0025] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0026] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0027] like Figure 1As shown, that is, a refrigerant circuit flow chart, an embodiment of the present invention discloses a separation system for a CO2 refrigeration unit ejection pre-position, comprising a medium-temperature compressor 1, an oil separator 2, an air cooler 3, a parallel heat exchanger 4, a separator 5, a pressure regulating valve 6, an ejector 7, a flash tank 8, a low-temperature evaporator 9, a medium-temperature evaporator 10 and a low-temperature compressor 11, wherein the output end of the medium-temperature compressor 1 is connected to the oil separator 2, the output end of the oil separator 2 is connected to the air cooler 3, the output end of the air cooler 3 is connected to the first inlet of the parallel heat exchanger 4, the first outlet of the parallel heat exchanger 4 is connected to the inlet of the separator 5, the separator 5 is used to separate the refrigerant into gas and liquid, and the separator The gas output end of the separator 5 is connected to the ejector 7, and the liquid output end of the separator 5 is connected to the flash tank 8. The output end of the ejector 7 is connected to the flash tank 8. The separated liquid or mist gas can be converted into liquid through the pressure regulating valve 6. The flash tank 8 includes a gas outlet and a liquid outlet, wherein the gas outlet is connected to the second inlet of the parallel heat exchanger 4, and the second outlet of the parallel heat exchanger 4 is connected to the medium-temperature compressor 1; the liquid outlet of the flash tank 8 is respectively connected to the low-temperature evaporator 9 and the medium-temperature evaporator 10. After passing through the low-temperature evaporator 9, the refrigerant enters the low-temperature compressor 11, mixes with the refrigerant passing through the medium-temperature evaporator 10, and enters the medium-pressure gas inlet of the ejector 7.

[0028] like Figure 2 , Figure 3 As shown, the separator includes a separator cylinder 51, the outer wall of the separator cylinder is provided with a refrigerant inlet 55, an impact plate 56 is provided at a position corresponding to the refrigerant inlet in the separator cylinder, an upper guide plate 54 is provided above the impact plate, a gas refrigerant outlet 59 is provided above the separator cylinder; a lower guide plate 57 is provided below the impact plate; and a liquid refrigerant outlet 513 is provided below the lower guide plate.

[0029] Furthermore, a separator upper end cover 52 is provided above the separator cylinder, and a separator lower end cover 512 is provided below the separator cylinder. The gas refrigerant outlet is provided on the separator upper end cover, and the liquid refrigerant outlet is provided on the separator lower end cover.

[0030] Further, the impact plate is arranged vertically, and a plurality of groups of auxiliary guide plates are arranged on the side of the impact plate facing the refrigerant inlet, and the auxiliary guide plates are arranged in a herringbone shape. Specifically, each group of auxiliary guide plates forms a herringbone structure, and the two auxiliary guide plates on the left and right of each group are staggered in the height direction, and the cross section formed by all the auxiliary guide plates can completely cover the projection shape of the refrigerant inlet on the impact plate; The back of the impact plate is connected to a middle-layer guide plate 510 , and the middle-layer guide plate is welded to the inner side of the separator cylinder.

[0031] Furthermore, the middle guide plate is a circular plate with evenly distributed through holes, and the sum of the cross-sectional areas of all the through holes must be larger than the cross-sectional area of ​​the refrigerant inlet. The middle guide plate not only has the functions of guiding and separating, but also serves as a back support and reinforcement for the impact plate.

[0032] Furthermore, the lower guide plate is a circular plate with a notch, the outer diameter of which matches the inner diameter of the separator cylinder, and which is welded to the inner side of the separator cylinder, and the notch is arranged on the outer circumferential surface of the circular plate, and is used to guide the refrigerant blocked by the impact plate. Thus, the liquid refrigerant flows into the lower layer and enters the system through the liquid refrigerant outlet pipe. At the same time, another key function of setting the lower guide plate is to guide the gas refrigerant from above to the middle and upper guide plates of the upper layer, thereby avoiding the impact of the high-pressure gas refrigerant on the liquid refrigerant surface of the lower layer, resulting in the instability of the liquid surface and affecting the monitoring data of the liquid level sensor.

[0033] Furthermore, the upper guide plate is a circular plate, on which evenly distributed through holes are opened, and the sum of the cross-sectional areas of all the through holes needs to be larger than the cross-sectional area of ​​the refrigerant inlet.

[0034] Furthermore, the positions of the circular holes of the upper guide plate and the middle guide plate are all staggered without overlap.

[0035] Furthermore, a filter screen 53 is provided between the upper guide plate and the upper end cover of the separator. The filter screen is made of stainless steel, and the height of the stainless steel filter screen is usually about 100 mm, and the mesh number of the filter screen is usually about 100 to 150. The height and mesh number of the filter screen can also be adjusted according to different working conditions.

[0036] Furthermore, a separator fixing piece 511 is provided on the outside of the separator cylinder and is welded to the separator cylinder. The size and quantity of the separator fixing piece can be adjusted according to different working conditions.

[0037] During use, the refrigerant flowing from the air cooler to the separator enters the separator through the refrigerant inlet 55, and flows directly to the impact plate 56, so that the liquid naturally falls through the gaps around the lower guide plate 57, flows into the lower end cover 512 of the separator, and enters the pressure regulating valve through the liquid refrigerant outlet 513. The gas refrigerant passes through the lower guide plate 57, the middle guide plate 510 and the upper guide plate 54, and the filter screen 53, and enters the ejector through the gas refrigerant outlet 59. In this way, the gas and liquid in the refrigerant from the air cooler are separated, so that what enters the ejector is gas refrigerant, which ensures the efficiency of the ejector.

[0038] As an expandable implementation method, a liquid level sensor interface 58 is also provided on the separator cylinder 1. The liquid level sensor interface is arranged in the interval between the lower guide plate and the lower end cover of the separator, and is used to monitor the liquid level in the separator.

[0039] The specific working process of the present invention is as follows: first, the medium-temperature compressor 1 compresses the refrigerant (refrigerant) to a high-temperature and high-pressure state, the refrigerant enters the oil separator 2, the high-temperature and high-pressure refrigerant gas enters the air cooler 3 for cooling, the low-temperature and high-pressure refrigerant enters the parallel heat exchanger 4, the refrigerant in the parallel heat exchanger enters the separator 5, the gas separated in the separator enters the ejector 7, the ejector 7 enters the flash tank 8 through the high-pressure gas and the low-pressure gas ejection; the liquid separated in the separator enters the flash tank 8 through the pressure regulating valve 6, and the gas in the flash tank 8 enters the medium-temperature compressor 1 through the parallel heat exchanger 4. The liquid in the flash tank 8 enters the low-temperature evaporator 9 and the medium-temperature evaporator 10. After passing through the low-temperature evaporator 9, the refrigerant enters the low-temperature compressor 11, mixes with the refrigerant passing through the medium-temperature evaporator 10, and enters the medium-pressure gas inlet of the ejector 7. Thus, the entire refrigeration work is completed.

[0040] The separator is located between the outlet of the air cooler and the high-pressure gas inlet of the ejector. After the high-pressure CO2 gas passes through the air cooler, a small amount of CO2 liquid or mist gas will enter the high-pressure gas inlet of the ejector through the pipeline. The separator is set before the ejector to separate the gas and directly enter the high-pressure gas inlet of the ejector. The separated liquid or mist gas can be converted into liquid through the pressure regulating valve and enter the flash tank. The gas and liquid in the high-pressure section can be separated without losing any system energy efficiency, so that the refrigerant entering the high-pressure gas inlet of the ejector is in a gaseous state, ensuring the efficiency of the ejector and thus the energy efficiency of the system.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A separation system for the pre-injection of a CO2 refrigeration unit, characterized in that: The invention comprises a medium-temperature compressor, an oil separator, an air cooler, a heat exchanger, a separator, a pressure regulating valve, an ejector, a flash tank, a low-temperature evaporator, a medium-temperature evaporator and a low-temperature compressor, wherein the output end of the medium-temperature compressor is connected to the oil separator, the output end of the oil separator is connected to the air cooler, the output end of the air cooler is connected to the first inlet of the heat exchanger, the first outlet of the heat exchanger is connected to the inlet of the separator, the separator is used to separate the refrigerant into gas and liquid, the gas output end of the separator is connected to the ejector, the liquid output end of the separator is connected to the flash tank, the output end of the ejector is connected to the flash tank, the flash tank comprises a gas outlet and a liquid outlet, wherein the gas outlet is connected to the second inlet of the heat exchanger, the second outlet of the heat exchanger is connected to the medium-temperature compressor; the liquid outlet of the flash tank is respectively connected to the low-temperature evaporator and the medium-temperature evaporator, the refrigerant enters the low-temperature compressor after passing through the low-temperature evaporator, is mixed with the refrigerant passing through the medium-temperature evaporator, and enters the medium-pressure gas inlet of the ejector.

2. The separation system for the pre-injection of a CO2 refrigeration unit according to claim 1 is characterized in that: The separator comprises a separator cylinder, the outer wall of the separator cylinder is provided with a refrigerant inlet, an impact plate is provided at a position corresponding to the refrigerant inlet in the separator cylinder, an upper guide plate is provided above the impact plate, a gas refrigerant outlet is provided above the separator cylinder; a lower guide plate is provided below the impact plate; A liquid refrigerant outlet is arranged below the lower guide plate.

3. The separation system for the pre-injection of a CO2 refrigeration unit according to claim 2 is characterized in that: A separator upper end cover is arranged above the separator cylinder, and a separator lower end cover is arranged below the separator cylinder. The gas refrigerant outlet is arranged on the separator upper end cover, and the liquid refrigerant outlet is arranged on the separator lower end cover.

4. The separation system for the pre-injection of a CO2 refrigeration unit according to claim 2 is characterized in that: The impact plate is arranged vertically, and a plurality of auxiliary guide plates are arranged on the side of the impact plate facing the refrigerant inlet, and the auxiliary guide plates are arranged in a herringbone shape. Specifically, each group of auxiliary guide plates forms a herringbone structure, and the two auxiliary guide plates on the left and right of each group are staggered in the height direction, and the cross section formed by all the auxiliary guide plates can completely cover the projection shape of the refrigerant inlet on the impact plate; The back side of the impact plate is connected with a middle-layer guide plate, and the middle-layer guide plate is welded to the inner side of the separator cylinder.

5. The separation system for the pre-injection of a CO2 refrigeration unit according to claim 4 is characterized in that: The middle guide plate is a circular plate, on which evenly distributed through holes are opened, and the sum of the cross-sectional areas of all the through holes must be larger than the cross-sectional area of ​​the refrigerant inlet.

6. The separation system for the pre-injection of a CO2 refrigeration unit according to claim 2 is characterized in that: The lower guide plate is a circular plate with a notch. The outer diameter of the lower guide plate matches the inner diameter of the separator cylinder. The lower guide plate is welded to the inner side of the separator cylinder. The notch is arranged on the outer circumferential surface of the circular plate to guide the refrigerant blocked by the impact plate.

7. The separation system for the pre-injection of a CO2 refrigeration unit according to claim 2 is characterized in that: The upper guide plate is a circular plate, on which evenly distributed through holes are opened, and the sum of the cross-sectional areas of all the through holes must be larger than the cross-sectional area of ​​the refrigerant inlet.

8. The separation system for the pre-injection of a CO2 refrigeration unit according to claim 4 is characterized in that: The circular hole positions of the upper guide plate and the middle guide plate are all staggered without overlap.

9. The separation system for the pre-injection of a CO2 refrigeration unit according to claim 2, characterized in that: A filter screen is arranged between the upper guide plate and the upper end cover of the separator, and the mesh number of the filter screen is 100-150 meshes.

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