CN117450698A - Refrigerant recovery system for refrigeration equipment test and control method thereof - Google Patents

Abstract

The invention provides a refrigerant recovery system for refrigeration equipment test and a control method thereof, comprising the following steps: the device comprises a condenser, an oil separator A, a first pipeline and a second pipeline, wherein one end of the first pipeline can be communicated with the oil separator A, the other end of the first pipeline can be communicated with the exhaust end of the compressor A, and one end of the second pipeline can be communicated with the first pipeline, and the other end of the second pipeline can be communicated with one end of the condenser; one end of the eighth pipeline can be communicated with the oil separator A, the other end of the eighth pipeline is communicated with the air inlet end of the compressor B so as to allow fluid to flow from the oil separator A to the compressor B in a recovery mode of the recovery system, the air outlet end of the compressor B is also communicated with the eleventh pipeline, and the refrigerant in the eleventh pipeline heats up the refrigerant in the fifth pipeline at the heat exchanger. According to the invention, the problem that the flowing direction of the refrigerant in the oil separator is inconsistent with that of the refrigerant in the recovery system in normal operation of the refrigeration equipment can be solved, and the problem that the refrigerant liquid stays in the liquid pipe is solved.

Description

Refrigerant recovery system for refrigeration equipment test and control method thereof

Technical Field

The invention relates to the technical field of refrigeration, in particular to a refrigerant recovery system for testing refrigeration equipment and a control method thereof.

Background

The emission of freon gas can destroy the atmosphere and cause greenhouse effect to cause global temperature rise and other environmental problems. The refrigeration equipment utilizing the Freon refrigerant is applied to various industries, and various links such as user use, after-sale maintenance and scrapping treatment and the like can be detected from source production, so that the phenomena of leakage of the Freon refrigerant, artificial private discharge and the like can be even caused. Along with the stricter supervision of the freon refrigerant, the freon refrigerant in each flow link needs to be strictly monitored, recycled and reused, and the like, and particularly, the refrigerant in the refrigeration equipment needs to be frequently moved in the testing and maintaining processes, so that the refrigerant is ensured not to leak into the atmosphere when the connecting pipe is disconnected.

After-sales maintenance is difficult to manage, after-sales maintenance is less frequently performed by using the refrigerant recovery equipment, and particularly, the after-sales maintenance of the household air conditioner has the phenomena of large refrigerant leakage and snow charging cost. On the other hand, some special air conditioners, particularly the compressors of the machine room air conditioners, are arranged on the indoor machine side with low pressure, the pressure-maintaining leak detection refrigerant in the production test process is different from the rated filling refrigerant of the machine set, the frequent connection test process is difficult to accurately control the filling quantity of the refrigerant in the machine set when leaving the factory, and basically, the refrigerant can only be pumped in vacuum to be refilled, and the process wastes the refrigerant very much, so that the production cost is high; the vacuumizing pressure-maintaining refrigerant reperfusion also wastes production time and causes low production efficiency.

It is necessary to develop a refrigerant recovery adjustment device for precisely transferring the original refrigerant in the refrigeration device during production, inspection and after-market maintenance, ensuring no waste and no leakage. The earlier patents CN202211334307.6 and CN202211333428.9 are designed and studied optimally, but when the recovery device related to this patent operates, the refrigerant in the pipeline between the condenser and the third check valve (check valve C) is in a liquid state, so that the refrigerant cannot return to the condenser, thereby affecting the operation efficiency of the recovery device.

The invention designs a refrigerant recovery system for testing the refrigeration equipment and a control method thereof, which are researched and designed because the technical problems that the operation efficiency of the recovery equipment is affected and the like because the refrigerant in a pipeline between a condenser and a third one-way valve is in a liquid state when the refrigeration recovery equipment in the prior art is operated.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the defect that the refrigerant in the pipeline between the condenser and the third one-way valve is in a liquid state when the refrigeration recovery equipment in the prior art is in operation, so that the refrigerant cannot return to the condenser, and the operation efficiency of the recovery equipment is affected, and therefore, the refrigerant recovery system for the refrigeration equipment test and the control method thereof are provided.

In order to solve the above problems, the present invention provides a refrigerant recovery system for testing a refrigeration device, comprising:

the device comprises a condenser, an oil separator A, a first pipeline and a second pipeline, wherein one end of the first pipeline can be communicated with the oil separator A, the other end of the first pipeline can be communicated with the exhaust end of the compressor A, and one end of the second pipeline can be communicated with the first pipeline, and the other end of the second pipeline can be communicated with one end of the condenser;

the condenser also comprises an expansion valve and a fifth pipeline, one end of the fifth pipeline can be communicated with the other end of the condenser, the other end of the fifth pipeline can be communicated with the expansion valve,

the system further comprises a compressor B, a heat exchanger and an eighth pipeline, wherein one end of the eighth pipeline can be communicated with the oil separator A, the other end of the eighth pipeline is communicated with the air inlet end of the compressor B so as to allow fluid to flow from the oil separator A to the compressor B in a recovery mode of a recovery system, the air outlet end of the compressor B is also communicated with an eleventh pipeline, a part of pipe section of the fifth pipeline is arranged in the heat exchanger in a penetrating manner, and a part of pipe section of the eleventh pipeline is arranged in the heat exchanger in a penetrating manner so as to heat and raise the temperature of the refrigerant in the fifth pipeline by the refrigerant in the eleventh pipeline at the heat exchanger.

In some embodiments of the present invention, in some embodiments,

when the compressor A is started, a refrigeration equipment test mode is operated, and at the moment, a mixture of the refrigerant and the lubricating oil discharged from the exhaust end of the compressor A enters the oil separator A through the first pipeline to realize oil-gas separation; when the compressor A is closed, a recovery mode of a recovery system is operated, and the mixture of the refrigerant and the lubricating oil in the condenser can enter the oil separator A through the second pipeline to realize oil-gas separation.

In some embodiments of the present invention, in some embodiments,

the heat exchanger is a sleeve heat exchanger and comprises a sleeve, part pipe sections of the fifth pipeline and the eleventh pipeline are respectively arranged in the sleeve in a penetrating manner, and an electric heating device A is further arranged on the sleeve so as to heat the refrigerant in the fifth pipeline; and/or, an electric heating device B is further arranged on a part of the pipe section of the fifth pipeline, which does not penetrate through the heat exchanger, so as to heat the refrigerant in the fifth pipeline.

In some embodiments of the present invention, in some embodiments,

a fourth pipe having one end connected to the inside of the oil separator a and the other end communicating with the second pipe so as to allow fluid to flow from the oil separator a to the second pipe in a refrigeration equipment test mode;

And an eighth pipeline, wherein one end of the eighth pipeline is communicated with the fourth pipeline, the other end of the eighth pipeline is communicated with the air inlet end of the compressor B, so that fluid can be allowed to flow from the oil separator A to the compressor B in a recovery mode of a recovery system, and a control valve is arranged on the eighth pipeline.

In some embodiments of the present invention, in some embodiments,

the first pipeline is connected with the second pipeline at a first position, the fourth pipeline is connected with the second pipeline at a second position, a pipe section of the second pipeline between the first position and the second position is a third pipeline, a one-way valve E is arranged on the third pipeline, and the one-way valve E can only allow refrigerant to flow from the second pipeline to the first pipeline;

the eighth pipeline is connected with the fourth pipeline at a third position, a one-way valve D is arranged on the fourth pipeline and positioned between the third position and the second position, and the one-way valve D can only allow the refrigerant to flow from the fourth pipeline to the second pipeline.

In some embodiments of the present invention, in some embodiments,

the system comprises a control valve, a compressor B, an oil separator, a first throttling device, a second throttling device, a first pipeline and a second pipeline, wherein one end of the first pipeline is communicated with the exhaust end of the compressor B, the other end of the first pipeline is communicated with the inside of the oil separator B, one end of the second pipeline is communicated with the inside of the oil separator B, the other end of the first pipeline is communicated with the first pipeline, the connection position of the second pipeline and the first pipeline is a sixth position, and the sixth position is positioned between the control valve and the compressor B; the second throttling device is arranged on the tenth pipeline; the eleventh pipeline is communicated with the air outlet of the oil separator B.

In some embodiments of the present invention, in some embodiments,

the system further comprises an evaporator, a sixth pipeline and a seventh pipeline, wherein one end of the sixth pipeline is communicated with the expansion valve, the other end of the sixth pipeline is communicated with the evaporator, one end of the seventh pipeline is communicated with the interior of the oil separator A, and the other end of the seventh pipeline is communicated with the fifth pipeline; the air outlet of the oil separator B is communicated with the seventh pipeline through the eleventh pipeline.

In some embodiments of the present invention, in some embodiments,

the eleventh pipeline is connected with the seventh pipeline at a fourth position, a one-way valve B is arranged on the eleventh pipeline and positioned on a pipeline section between the heat exchanger and the fourth position, and the one-way valve B can only allow the refrigerant to flow from the eleventh pipeline to the seventh pipeline;

the fifth pipeline is connected with the seventh pipeline at a fifth position, a one-way valve C is arranged on the pipe section of the fifth pipeline and positioned between the heat exchanger and the fifth position, and the one-way valve C can only allow the refrigerant to flow from the fifth pipeline to the expansion valve;

the seventh pipeline is provided with a first throttling device and a one-way valve A, the first throttling device and the one-way valve are arranged between the oil separator A and the fourth position, and the one-way valve A can only allow fluid to flow from the oil separator A to the fifth pipeline.

In some embodiments of the present invention, in some embodiments,

the first pipeline is also provided with an air valve, an interface A and an interface C, and a liquid valve, an interface B and an interface D are arranged on the fifth pipeline and between the fifth position and the expansion valve; an interface E is arranged on the second pipeline, and an interface F is arranged on the fifth pipeline and between the fifth position and the condenser; and a fluorine injection nozzle is arranged between the evaporator and the compressor A.

The invention also provides a control method of the refrigerant recovery system for the test of the refrigeration equipment, which comprises the following steps:

judging, namely judging whether the operation mode required by the refrigerant recovery system is a refrigeration equipment test mode or a recovery mode of the recovery system;

a control step of controlling the compressor A to be opened, controlling the compressor B to be closed and controlling the control valve to be closed when the operation mode required by the refrigerant recovery system needs to be operated in a refrigeration equipment test mode; when the operation mode required by the refrigerant recovery system needs to be operated in the recovery mode of the recovery system, the compressor A is controlled to be closed, the compressor B is controlled to be opened, and the control valve is controlled to be opened.

The invention provides a refrigerant recovery system for testing refrigeration equipment and a control method thereof, which comprises the following steps of

The beneficial effects are that:

1. according to the invention, the first pipeline, the second pipeline, the oil separator A, the compressor A and the condenser are arranged, so that the first pipeline and the second pipeline are respectively communicated with the compressor A, the oil separator A and the condenser, through the arrangement of the valves on the pipelines, the mixture of the refrigerant and the oil discharged by the compressor A enters the oil separator A through the first pipeline for oil-gas separation in a test mode of refrigeration equipment, and the mixture of the refrigerant and the oil in the condenser part enters the oil separator A through the second pipeline for oil-gas separation in a recovery mode of the recovery system through closing the compressor A, thereby effectively enabling different test modes and recovery modes to enter the oil separator A through the first pipeline for oil-gas separation, enabling the flow directions of the refrigerant in the oil separator to be consistent with the flow directions of the refrigerant in the recovery system in a normal operation of the refrigeration equipment, and solving the problem that the flow directions of the refrigerant in the oil separator are inconsistent in the normal operation of the refrigeration equipment and the recovery system in the normal operation of the refrigeration equipment, and further solving the problem of low efficiency of the oil separator in the recovery system in the prior art; when the recovery system is connected with the refrigeration equipment, the problems of refrigerant recovery after the online test is finished, mutual mixing of refrigeration oil of the refrigeration equipment and the recovery system and the like can be solved through different valve opening and closing combinations and operation control of the recovery compressor B. No special pressure vessel for storing the refrigerant is needed, and the consistency of the refrigerant filling quantity of the refrigeration equipment is ensured. The invention further provides power for the refrigerant in the recovery mode to promote the recovery of the refrigerant, and the heat exchanger and the eleventh pipeline arranged at the exhaust end of the compressor B can exchange heat with the fifth pipeline at the heat exchanger, so that the refrigerant in the fifth pipeline is heated by using the high-temperature heat of the exhaust of the compressor B, the liquid refrigerant in the fifth pipeline is heated to be in a gaseous state in the recovery mode, and the refrigerant liquid retained in the liquid pipe is heated by utilizing the waste heat of the high-temperature exhaust of the recovery compressor B and/or the electric heating current so as to accelerate the gasification, thereby effectively recovering the refrigerant in the part of pipelines, improving the recovery efficiency of the recovery equipment, improving the recovery operation efficiency, avoiding the retention of the refrigerant liquid in the liquid pipe, fully utilizing the waste heat of the high-temperature exhaust of the recovery compressor, and being beneficial to improving the recovery efficiency and energy efficiency of the recovery equipment.

2. According to the invention, the electric heating device A arranged on the heat exchanger and the electric heating device B arranged on the fifth pipeline can further improve the heating efficiency of the refrigerant in the fifth pipeline, so that the refrigerant liquid retained in the fifth pipeline (liquid pipe) can be gasified further and accelerated, the recovery efficiency of the part of liquid refrigerant is further improved, and the recovery operation efficiency is further improved.

Drawings

Fig. 1 is a block diagram of a refrigerant recovery system for testing a refrigeration apparatus according to the present invention.

The reference numerals are expressed as:

1. a compressor A; 2. a heat exchanger; 3. a condenser; 4. an evaporator; 5. an expansion valve; 6. an oil separator A; 71. a one-way valve A; 72. a one-way valve B; 73. a one-way valve C; 74. a one-way valve D; 75. a one-way valve E; 81. a first throttle device; 82. a second throttle device; 9. a compressor B; 10. an oil separator B; 11. a first position; 12. a second position; 13. a third position; 14. a fourth position; 15. a fifth position; 16. a sixth position; 13', an air valve; 141. an interface A; 142. an interface B; 143. an interface C; 144. an interface D; 145. an interface E; 146. an interface F;15', a liquid valve; 16', a fluorine injection nozzle; 171. a gas fluorine pipe; 172. a liquid fluorine pipe; 18. a control valve; 191. an electric heating device A; 192. an electric heating device B; 101. a first pipeline; 102. a second pipeline; 103. a third pipeline; 104. a fourth pipeline; 105. a fifth pipeline; 106. a sixth pipeline; 107. a seventh pipeline; 108. an eighth pipeline; 109. a ninth pipeline; 110. a tenth pipeline; 111. and an eleventh pipeline.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

In the description of the present invention, it should be understood that the azimuth or positional relationships indicated by the azimuth terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal", and "top, bottom", etc., are generally based on the azimuth or positional relationships shown in the drawings, merely to facilitate description of the present invention and simplify the description, and these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present invention; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, the terms "first", "second", etc. are used to define the components, and are only for convenience of distinguishing the corresponding components, and the terms have no special meaning unless otherwise stated, and therefore should not be construed as limiting the scope of the present invention.

As shown in fig. 1, the present invention provides a refrigerant recovery system for testing a refrigeration device, which comprises:

a compressor A1, a condenser 3, an oil separator A6, a first pipe 101, and a second pipe 102, wherein one end of the first pipe 101 can be communicated with the oil separator A6, the other end can be communicated with an exhaust end of the compressor A1, and one end of the second pipe 102 can be communicated with the first pipe 101, and the other end can be communicated with one end of the condenser 3;

and further comprises an expansion valve 5 and a fifth pipe 105, one end of the fifth pipe 105 can be communicated with the other end of the condenser 3, the other end can be communicated with the expansion valve 5,

the system further comprises a compressor B9, a heat exchanger 2 and an eighth pipeline 108, wherein one end of the eighth pipeline 108 can be communicated with the oil separator A6, the other end of the eighth pipeline 108 is communicated with the air inlet end of the compressor B9 so as to allow fluid to flow from the oil separator A6 to the compressor B9 in a recovery mode of a recovery system, the air outlet end of the compressor B9 is also communicated with an eleventh pipeline 111, a part of pipe section of the fifth pipeline 105 penetrates into the heat exchanger 2, and a part of pipe section of the eleventh pipeline 111 penetrates into the heat exchanger 2 so as to heat and raise the temperature of the refrigerant in the fifth pipeline 105 by the refrigerant in the eleventh pipeline 111 at the heat exchanger 2. (as shown in FIG. 1, the first conduit 101 is preferably in communication with the discharge end of the compressor A1 via a gas fluorine tube 171).

According to the invention, the first pipeline, the second pipeline, the oil separator A, the compressor A and the condenser are arranged, so that the first pipeline and the second pipeline are respectively communicated with the compressor A, the oil separator A and the condenser, through the arrangement of the valves on the pipelines, the mixture of the refrigerant and the oil discharged by the compressor A enters the oil separator A through the first pipeline for oil-gas separation in a test mode of refrigeration equipment, and the mixture of the refrigerant and the oil in the condenser part enters the oil separator A through the second pipeline for oil-gas separation in a recovery mode of the recovery system through closing the compressor A, thereby effectively enabling different test modes and recovery modes to enter the oil separator A through the first pipeline for oil-gas separation, enabling the flow directions of the refrigerant in the oil separator to be consistent with the flow directions of the refrigerant in the recovery system in a normal operation of the refrigeration equipment, and solving the problem that the flow directions of the refrigerant in the oil separator are inconsistent in the normal operation of the refrigeration equipment and the recovery system in the normal operation of the refrigeration equipment, and further solving the problem of low efficiency of the oil separator in the recovery system in the prior art; when the recovery system is connected with the refrigeration equipment, the problems of refrigerant recovery after the online test is finished, mutual mixing of refrigeration oil of the refrigeration equipment and the recovery system and the like can be solved through different valve opening and closing combinations and operation control of the recovery compressor B. No special pressure vessel for storing the refrigerant is needed, and the consistency of the refrigerant filling quantity of the refrigeration equipment is ensured. The invention further provides power for the refrigerant in the recovery mode to promote the recovery of the refrigerant, and the heat exchanger and the eleventh pipeline arranged at the exhaust end of the compressor B can exchange heat with the fifth pipeline at the heat exchanger, so that the refrigerant in the fifth pipeline is heated by using the high-temperature heat of the exhaust of the compressor B, the liquid refrigerant in the fifth pipeline is heated to be in a gaseous state in the recovery mode, and the refrigerant liquid retained in the liquid pipe is heated by utilizing the waste heat of the high-temperature exhaust of the recovery compressor B and/or the electric heating current so as to accelerate the gasification, thereby effectively recovering the refrigerant in the part of pipelines, improving the recovery efficiency of the recovery equipment, improving the recovery operation efficiency, avoiding the retention of the refrigerant liquid in the liquid pipe, fully utilizing the waste heat of the high-temperature exhaust of the recovery compressor, and being beneficial to improving the recovery efficiency and energy efficiency of the recovery equipment.

According to the invention, the compressor B can provide power for the recovery mode, refrigerant gas is sucked from the oil separator A, so that the refrigerant and oil in the drive condenser can flow back to the oil separator A through the second pipeline for normal oil-gas separation, the oil-gas mixture at the exhaust end of the compressor B can be subjected to oil-gas separation through the arrangement of the oil separator B, and the oil separated in the oil separator B can be led to the inlet end of the compressor B through the arrangement of the tenth pipeline, so that the internal components of the compressor B are ensured to be lubricated and cooled continuously.

As shown in fig. 1, the recovery device is provided with four interfaces of C/D/E/F, wherein the interface C is connected with an interface A of the indoor unit through a gas fluorine pipe, the interface D is connected with an interface B of the indoor unit through a liquid fluorine pipe, and the interfaces E/F are respectively connected with an inlet and an outlet of the outdoor unit; an air valve is also arranged on the exhaust pipe of the indoor unit, and a liquid valve is arranged on the liquid return pipe of the indoor unit. A one-way valve E is arranged on the air suction pipeline between the interface C and the interface E, and the flow direction of the one-way valve E is that the interface E flows to the interface C; and a one-way valve C is arranged on the exhaust pipeline between the interface D and the interface F, and the flow direction of the one-way valve C is that the interface F flows to the interface D.

The invention adopts a special recovery system to solve the technical problems, and the refrigerating oil separated by the refrigerating equipment is recovered in advance by connecting an inlet and an outlet of the refrigerant recovery system with an oil return pipeline; the refrigerant oil recovery of the recovery system is realized by connecting a high-low pressure port of a recovery compressor of the refrigerant recovery system with an oil return branch; the combination of the control valve and the one-way valve realizes that the flow direction of the refrigerant is kept consistent when the refrigeration equipment runs and the refrigerant flow direction is kept consistent when the recovery system runs, so that the problem of low efficiency of the oil separator when the recovery system in the prior art runs is solved; when the recovery system is connected with the refrigeration equipment, the problems of refrigerant recovery after the online test is finished, mutual mixing of refrigeration oil of the refrigeration equipment and the recovery system and the like can be solved through different valve opening and closing combinations and operation control of the recovery compressor B. No special pressure vessel for storing the refrigerant is needed, and the consistency of the refrigerant filling quantity of the refrigeration equipment is ensured.

According to the invention, through the combined design of the two compressors, the multiple pipelines and the multiple one-way valves, the flow direction of the refrigerant in the oil separator is ensured to be consistent with that of the refrigerant in the recovery system when the refrigeration equipment is operated, so that the oil separator can realize efficient separation of lubricating oil under two conditions (1. In compression refrigeration, namely in a normal test mode, and 2. In the operation recovery mode when the compressor is stopped, namely in the test end).

The invention solves the following technical problems:

1. and the refrigerant flowing direction in the oil separator is inconsistent when the refrigeration equipment is in normal operation and the recovery system is in operation. (since the outlet tube does not ensure that the refrigerant is centrifugally rotated in the interior of the oil separator when entering the oil separator in the reverse direction from the outlet tube, centrifugal separation is not achieved without centrifugal movement.)

2. And the control switching problem before the recovery system is started at the end of the test, the problem of the control method of the recovery system and the like.

3. The problem that refrigerant liquid stays in the liquid pipe in the recovery mode is solved, waste heat of high-temperature exhaust gas of the recovery compressor is fully utilized, and recovery efficiency and energy efficiency of recovery equipment are improved.

In some embodiments, when the compressor A1 is started, a refrigeration equipment test mode is operated, wherein a mixture of the refrigerant and the lubricating oil discharged from the discharge end of the compressor A1 enters the oil separator A6 through the first pipeline 101 to realize oil-gas separation; when the compressor A1 is turned off, a recovery system recovery mode is operated, in which a mixture of refrigerant and lubricating oil in the condenser 3 can enter the oil separator A6 via the second line 102 to effect oil-gas separation.

This is a further preferred form of construction of the invention, namely, when the compressor a is started, refrigerant and oil enter the oil separator a from the first pipeline to undergo oil-gas separation, and the separated gas enters the condenser through the second pipeline; when the compressor A is closed, the flow directions of the refrigerant in the second pipeline are opposite, the refrigerant enters the oil separator A from the condenser through the second pipeline to perform oil-gas separation, but the flow directions of the refrigerant entering the oil separator A are the same, and the refrigerant enters the oil separator A through the first pipeline, so that the directions of fluid flowing to the oil separator A in two different modes are both consistent, and the normal and efficient oil-gas separation of the oil separator A is effectively ensured.

In some embodiments of the present invention, in some embodiments,

the heat exchanger 2 is a sleeve heat exchanger, and comprises a sleeve, wherein part of pipe sections of the fifth pipeline 105 and the eleventh pipeline 111 are respectively arranged in the sleeve in a penetrating way, and an electric heating device A191 is further arranged on the sleeve so as to heat the refrigerant in the fifth pipeline 105; and/or, an electric heating device B192 is further disposed on a part of the fifth pipeline 105 that does not pass through the heat exchanger 2, so as to heat the refrigerant in the fifth pipeline 105.

According to the invention, the electric heating device A arranged on the heat exchanger and the electric heating device B arranged on the fifth pipeline can further improve the heating efficiency of the refrigerant in the fifth pipeline, so that the refrigerant liquid retained in the fifth pipeline (liquid pipe) can be gasified further and accelerated, the recovery efficiency of the part of liquid refrigerant is further improved, and the recovery operation efficiency is further improved.

The invention adds a sleeve heat exchanger, an electric heating device A and an electric heating device B on recovery equipment; the waste heat of the high-temperature exhaust gas of the recovery compressor B and/or the refrigerant liquid retained in the electric heating and electrifying heating liquid pipe are utilized to accelerate gasification, so that the recovery efficiency is improved; the invention adopts a double-pipe heat exchanger and/or electric heating, and utilizes high-temperature exhaust gas of the recovery compressor B and/or electric heating equipment to heat the refrigerant liquid retained in the liquid pipe so as to accelerate gasification. Therefore, the retention of refrigerant liquid in the liquid pipe can be avoided, the waste heat of high-temperature exhaust gas of the recovery compressor can be fully utilized, and the recovery efficiency and the energy efficiency of recovery equipment can be improved.

In order to solve the technical problems in the background art, a heat source is added on the basis of the recovery equipment to heat and gasify the liquid refrigerant retained in the liquid pipe:

A double-pipe heat exchanger is added between the interface F and the inlet of the one-way valve C, the air outlet of the oil separator B is connected to the inlet of the inner pipe of the double-pipe heat exchanger, and the outlet of the inner pipe of the double-pipe heat exchanger is connected to the inlet of the one-way valve B; the interface F is connected to the shell side inlet of the double-pipe heat exchanger, and the inlet of the one-way valve C is connected to the shell side outlet of the double-pipe heat exchanger;

further, an electric heating device A is also wound on the outer wall of the sleeve heat exchanger;

further, an electric heating device B is wound on the outer wall of the liquid pipe between the outlet of the liquid pipe of the condenser and the interface F.

The high-temperature exhaust refrigerant at the outlet of the compressor B exchanges heat with the liquid refrigerant retained in the liquid pipe in the double-pipe heat exchanger, and the retained liquid refrigerant is heated and gasified; the electric heating device A and/or the electric heating device B wound on the outer wall can heat and gasify the liquid refrigerant retained in the liquid pipe. It should be noted that: the electric heating device A can be arranged in the shell side of the sleeve and soaked in the retained liquid refrigerant, so that the heat of electric heating can be utilized more fully (the electric heating device B can only be wound, because the electric heating device B is not preset in the liquid pipe when the refrigeration equipment leaves the factory, the electric heating device A belongs to the parts of the recovery equipment and can be designed and optimized in advance, the electric heating device B is also used as the parts of the recovery equipment, and the electric heating device B is wound to the illustrated position when the refrigeration equipment is used on site).

In some embodiments, a fourth conduit 104 is further included, one end of the fourth conduit 104 being connected to the interior of the oil separator A6, the other end being in communication with the second conduit 102 to allow fluid to flow from the oil separator A6 to the second conduit 102 in a refrigeration equipment testing mode;

an eighth conduit 108 is also included, one end of the eighth conduit 108 is in communication with the fourth conduit 104, and the other end is in communication with the air intake end of the compressor B9, so as to allow fluid to flow from the oil separator A6 to the compressor B9 in the recovery mode of the recovery system, and a control valve 18 is provided on the eighth conduit 108.

The invention can effectively lead out the gas exhaust separated by the oil separator A to the second pipeline when the compressor A is started, and the eighth pipeline is used for leading out the refrigerant separated in the oil separator to the compressor B when the compressor A is closed (when the compressor B is started), and the inlet end of the oil separator A sucks the refrigerant from the condenser 3 through the first pipeline and the second pipeline, thus realizing a refrigeration equipment test mode and a recovery system recovery mode respectively, and sucking and leading out the refrigerant in the structures such as the check valve C, the condenser 3 and the like to an indoor unit through the suction of the compressor B when the recovery system is in the recovery mode.

In some embodiments of the present invention, in some embodiments,

the first pipeline 101 is connected with the second pipeline 102 at a first position 11, the fourth pipeline 104 is connected with the second pipeline 102 at a second position 12, a pipe section of the second pipeline 102 between the first position 11 and the second position 12 is a third pipeline 103, a check valve E75 is arranged on the third pipeline 103, and the check valve E75 can only allow the refrigerant to flow from the second pipeline 102 to the first pipeline 101;

the eighth pipeline 108 is connected to the fourth pipeline 104 at the third position 13, and a check valve D74 is disposed on the fourth pipeline 104 and on a pipe section located between the third position 13 and the second position 12, and the check valve D74 can only allow the refrigerant to flow from the fourth pipeline 104 to the second pipeline 102.

The one-way valve E is arranged to prevent gas at the exhaust port of the compressor A from directly entering the condenser without passing through the oil separator A when the compressor A is started, so that the phenomenon that no refrigerant flows in the oil separator A is avoided; the check valve D is provided to prevent the refrigerant and oil returned from the condenser through the second line from being returned to the compressor B through the fourth line when the compressor a is turned off, (to prevent the eighth line 108 from bypassing the oil separator a, which is connected in parallel with the eighth line 108, from passing through the oil separator a only by a small amount of fluid), and to prevent the oil separator a from being unable to separate oil from gas due to a small fluid flow rate.

The oil return pipeline (comprising a first pipeline 101, a fourth pipeline 104 and a seventh pipeline 107) comprises three pipeline ports, namely an air inlet (namely the first pipeline 101) of the oil separator A6, an air outlet (namely the fourth pipeline 104) of the oil separator A6 and an oil return port (namely the seventh pipeline 107) of the oil return pipeline, wherein a capillary A (a first throttling device 81) and a one-way valve A71 are connected between the oil return port and an oil outlet of the oil separator A6, and the arrangement direction of the one-way valve A71 is that the oil outlet of the oil separator flows to the oil return port.

In some embodiments of the present invention, in some embodiments,

the system further comprises an oil separator B10, a second throttling device 82, a ninth pipeline 109 and a tenth pipeline 110, wherein one end of the ninth pipeline 109 is communicated with the exhaust end of the compressor B9, the other end of the ninth pipeline is communicated with the inside of the oil separator B10, one end of the tenth pipeline 110 is communicated with the inside of the oil separator B10, the other end of the tenth pipeline is communicated with the eighth pipeline 108, the connection position of the tenth pipeline 110 and the eighth pipeline 108 is a sixth position 16, and the sixth position 16 is positioned between the control valve 18 and the compressor B9; the second throttling device 82 is disposed on the tenth pipe 110; the eleventh pipeline 111 is communicated with an air outlet of the oil separator B10.

According to the invention, the oil-gas mixture at the exhaust end of the compressor B can be subjected to oil-gas separation through the arrangement of the oil separator B, and the oil separated in the oil separator B can be guided to the inlet end of the compressor B through the arrangement of the tenth pipeline, so that the internal components of the compressor B are ensured to be lubricated and cooled continuously. The compression pipeline comprises a compressor B, an oil separator B and a one-way valve B which are sequentially connected, wherein an inlet of the compression pipeline, namely, an air suction port of the compressor B is connected to a pipeline between an air outlet of the oil separator A and an inlet of the one-way valve D, and an oil outlet of the oil separator B is connected to a pipeline between the compressor B and the air outlet of the oil separator A through a capillary B; the outlet of the compression pipeline, namely the outlet of the one-way valve B, is connected to the pipeline between the interface D and the one-way valve C.

In some embodiments of the present invention, in some embodiments,

the system further comprises an evaporator 4, a sixth pipeline 106 and a seventh pipeline 107, wherein one end of the sixth pipeline 106 is communicated with the expansion valve 5, the other end of the sixth pipeline is communicated with the evaporator 4, one end of the seventh pipeline 107 is communicated with the interior of the oil separator A6, and the other end of the seventh pipeline 107 is communicated with the fifth pipeline 105; the air outlet of the oil separator B10 is connected to the seventh pipe 107 through the eleventh pipe 111. As shown in fig. 1, the fifth line 105 communicates with the expansion valve 5 through a liquid fluorine pipe 172.

According to the invention, the evaporator, the expansion valve, the condenser and the compressor A can be effectively formed into a refrigeration cycle loop through the arrangement of the sixth pipeline, and the seventh pipeline is used for guiding oil separated from the bottom of the oil separator A into the fifth pipeline and returning the oil to the compressor A so as to realize recovery of the oil.

In some embodiments of the present invention, in some embodiments,

the eleventh pipeline 111 and the seventh pipeline 107 are connected at a fourth position 14, a one-way valve B72 is arranged on the pipe section of the eleventh pipeline 111 and between the heat exchanger 2 and the fourth position 14, and the one-way valve B72 can only allow the refrigerant to flow from the eleventh pipeline 111 to the seventh pipeline 107;

the fifth pipeline 105 is connected with the seventh pipeline 107 at a fifth position 15, a one-way valve C73 is arranged on the fifth pipeline 105 and on a pipe section between the heat exchanger 2 and the fifth position 15, and the one-way valve C73 can only allow the refrigerant to flow from the fifth pipeline 105 to the expansion valve 5;

the seventh pipe 107 is provided with a first throttle device 81 and a check valve a71, wherein the first throttle device 81 and the check valve 71 are disposed between the oil separator A6 and the fourth position 14, and the check valve a71 only allows fluid to flow from the oil separator A6 to the fifth pipe 105.

The invention can guide the refrigerant gas separated by the oil separator B to the fifth pipeline through the arrangement of the eleventh pipeline and the one-way valve B, thereby being capable of returning to the indoor unit, and the one-way valve B is used for preventing the condition that the refrigerant and oil from the fifth pipeline and the like flow back into the oil separator B;

the oil return pipeline comprises three pipeline ports, namely an air inlet of the oil separator, an air outlet of the oil separator and an oil return port of the oil return pipeline, wherein a capillary A and a one-way valve A are connected between the oil return port and an oil outlet of the oil separator, and the flowing direction of the one-way valve A is that the oil outlet of the oil separator flows to the oil return port. The air inlet of the oil separator is connected between the interface C and the one-way valve E; the air outlet of the oil separator is connected between the interface E and the one-way valve E through the one-way valve D, and the flowing direction of the one-way valve D is that the air outlet of the oil separator flows to the interface E; the oil return port of the oil return pipeline is connected between the interface D and the one-way valve C.

The compression pipeline comprises an electromagnetic valve (a control valve 18), a compressor B, an oil separator B and a one-way valve B which are sequentially connected, and an oil outlet of the oil separator B is connected to a pipeline between the compressor B and the electromagnetic valve through a capillary B; the inlet of the compression pipeline, namely the inlet of the electromagnetic valve, is connected to a pipeline between the air outlet of the oil separator A and the one-way valve D; the outlet of the compression pipeline, namely the outlet of the one-way valve B, is connected to the pipeline between the interface D and the one-way valve C.

The invention can also throttle and decompress high-pressure oil through the first throttling device arranged on the seventh pipeline, so as to ensure that lubricating oil continuously passes through and prevent refrigerant gas from passing through in a large quantity, and the condition that the refrigerant and oil of the fifth pipeline and the like flow back into the oil separator A can be avoided through the arrangement of the one-way valve A.

Further preferably, the first throttling means is a capillary tube a and the second throttling means is a capillary tube B.

In some embodiments of the present invention, in some embodiments,

the first pipeline 101 is further provided with a gas valve 13', a connector A141 and a connector C143, and a liquid valve 15', a connector B142 and a connector D144 are arranged on the fifth pipeline 105 and between the fifth position 15 and the expansion valve 5; an interface E145 is provided on the second pipe 102, and an interface F146 is provided on the fifth pipe 105 between the fifth position 15 and the condenser 3; a fluorine injection nozzle 16' is arranged between the evaporator 4 and the compressor A1.

As shown in FIG. 1, the indoor unit at least comprises a compressor A, an evaporator, an expansion valve, a gas valve and a liquid valve, wherein the gas valve is connected with an interface A (gas outlet), and the liquid valve is connected with an interface B (liquid inlet). The air valve and the liquid valve are also provided with fluorine injection nozzles, the air valve and the liquid valve can be opened or closed manually, when the air valve and/or the liquid valve are closed, the fluorine injection nozzle on the air valve or the liquid valve can only be communicated with an outdoor unit or an indoor unit, and when the air valve or the liquid valve is closed, the fluorine injection nozzle on the air valve or the liquid valve is communicated with the outdoor unit and is not communicated with the indoor unit; the outdoor unit at least comprises a condenser, an air inlet and a liquid outlet.

The invention can effectively connect the indoor unit, the recovery system and the outdoor unit into an integral structure through the arrangement of the valves and the interfaces, and controls the corresponding valves and the interfaces to be opened or closed according to the needs, thereby ensuring the normal and reliable operation of the test mode and the recovery mode of the refrigeration equipment.

The invention also provides a control method of the refrigerant recovery system for the refrigeration equipment test, wherein:

judging, namely judging whether the operation mode required by the refrigerant recovery system is a refrigeration equipment test mode or a recovery mode of the recovery system;

a control step of controlling the compressor A1 to be turned on, controlling the compressor B9 to be turned off, and controlling the control valve 18 to be turned off when an operation mode required by the refrigerant recovery system is required to be operated in a refrigeration equipment test mode; when the operation mode required by the refrigerant recovery system needs to be operated in the recovery mode of the recovery system, the compressor A1 is controlled to be turned off, the compressor B9 is controlled to be turned on, and the control valve 18 is controlled to be turned on.

The invention also controls the compressor A and the compressor B according to the difference of the test mode of the refrigeration equipment and the recovery mode of the recovery system and controls the control valve, so that the refrigerant is provided with power to promote the recovery of the refrigerant in the recovery mode, and the heat exchange between the heat exchanger and the eleventh pipeline arranged at the exhaust end of the compressor B and the fifth pipeline can be carried out at the heat exchanger, thereby heating the refrigerant in the fifth pipeline by utilizing the high-temperature heat of the exhaust gas of the compressor B, heating the liquid refrigerant in the fifth pipeline to be in a gaseous state in the recovery mode, and utilizing the waste heat of the high-temperature exhaust gas of the recovery compressor B and/or the refrigerant liquid retained in the electrified heating liquid pipe to accelerate the gasification, thereby effectively recovering the refrigerant in the part of pipelines, improving the recovery efficiency of the recovery equipment, avoiding the retention of the refrigerant liquid in the liquid pipe, fully utilizing the high-temperature exhaust heat of the recovery compressor, and being beneficial to the recovery efficiency and the recovery efficiency of the recovery equipment.

The working principle of the recovery system is described as follows:

1) Test mode of refrigeration equipment

When the traditional refrigeration equipment is produced and tested, the indoor unit and the outdoor unit are in a separated state, and meanwhile, the outdoor unit is very simple, so that a complex electric control system is not configured, but the indoor unit is complex in structure and is configured with the electric control system, so that the indoor unit is mainly subjected to online test and refrigeration system leakage detection on a production line. The common practice is as follows: the indoor unit fills a small amount of refrigerant to be used as leakage detection, the outdoor unit is provided with a sufficient amount of refrigerant by adopting a test tool, the test tool of the outdoor unit is used for running with the refrigerant after the indoor unit and the outdoor unit are connected, and after the test is finished, the liquid valve is closed to press the refrigerant into the test tool of the outdoor unit through the compressor, wherein the test tool comprises a small amount of refrigerant for leakage detection of the original indoor unit. Because the testing tool of the same outdoor unit is adopted to test a plurality of indoor units, the leak detection refrigerants of the original indoor units can be accumulated in the testing tool of the outdoor unit one by one, so that more and more refrigerants of the testing tool can be accumulated, more compressor refrigerating oil can be discharged or adjusted to be stored in other pressure containers at regular intervals, the testing accuracy is influenced, the production cost is wasted, the production time is prolonged, and the production efficiency is reduced.

The production test flow related to the invention is different from the traditional test flow, and is briefly described as follows:

the interface E of the recovery system is connected with the air inlet of the outdoor unit, the interface F is connected with the liquid outlet of the outdoor unit, after connection is completed, the recovery system and the outdoor unit are used as test tools for online testing on a production line, and only the interface A and the interface C are connected through a gas fluorine pipe, and the interface B and the interface D are connected through a liquid fluorine pipe, so that rated filling quantity or test filling quantity of the filling unit in the indoor unit is required to replace a small quantity of original refrigerant for leakage detection. Valves on the interfaces A/BC/D/E/F are all opened, and the one-way valve A/B/C/D is automatically turned on or turned off according to the pressure difference between two ends of the one-way valve A/B/C/D; and connecting a vacuum pump to the recovery system and the outdoor unit through an air valve and/or a fluorine injection nozzle on the liquid valve, closing a valve of a vacuum pumping meter after the vacuum pumping is qualified, closing the vacuum pump, opening the air valve and the liquid valve, and taking down the vacuum pumping meter later.

After the refrigeration equipment stops running, switching control exists before the recovery equipment is started to recover the refrigerant:

the outer fan is stopped for t seconds, high-temperature and high-pressure refrigerant gas discharged by the compressor can wash out liquid refrigerant in the condenser and return to the indoor unit as soon as possible, then the operation of the compressor and the inner fan is stopped, and the outer fan is started to cool the residual refrigerant in the condenser;

Closing the air valve, waiting for m seconds to realize pressure balance between the indoor unit and the outdoor unit as soon as possible; the electric heating device A and/or the electric heating device B are/is started to heat and gasify the liquid refrigerant retained in the liquid pipe, and the gasified refrigerant can push part of the liquid refrigerant to enter the evaporator of the indoor unit through the one-way valve C and also can push part of the liquid refrigerant to return to the inside of the condenser.

After the steps a) and b) are completed, the transition control of the operation mode and the recovery mode of the refrigeration equipment is realized, and then the recovery equipment can be started to execute the recovery mode:

2) The reclamation apparatus executes reclamation mode

Opening an electromagnetic valve, starting a compressor B, and pressing the residual refrigerant on the outdoor unit back to the indoor unit through the compressor B, and adjusting the rotating speed of the inner fan according to the pressure of the indoor unit, so that the high-temperature and high-pressure refrigerant gas discharged into the evaporator by the compressor B is condensed and liquefied as soon as possible (the effect is that the gas is prevented from filling the space of the evaporator, and the recovery of as much refrigerant as possible is ensured); the outer fan of the outdoor unit runs at a high speed, so that the residual refrigerant liquid in the condenser is gasified as soon as possible and is sucked by the compressor B, the oil separator A can separate and store lubricating oil of the original refrigeration equipment and realize gas-liquid separation at the same time, and the liquid refrigerant which is not evaporated completely is prevented from directly returning to the compressor B; the oil separator B can separate the refrigerant at the outlet of the compressor B from the lubricating oil, so that the normal circulation of the lubricating oil of the compressor B is ensured. In summary, the two oil separators can isolate lubricating oil between the two compressors to the greatest extent, so that excessive mixing of the lubricating oil between the two compressors is avoided, and the two compressors are ensured to have enough lubricating oil.

The refrigerant cycle in the recovery mode of the recovery apparatus is: the method comprises the steps of a one-way valve C inlet, a sleeve shell side, a connector F, a condenser, a connector E, a one-way valve E, an oil separator A, an electromagnetic valve, a compressor B, an oil separator B, a sleeve tube side, a one-way valve B, a connector D, a connector B, a liquid valve, an expansion valve and an evaporator.

When the suction pressure and/or temperature of the compressor B is detected to be at the critical point Low, indicating that the recovery of the refrigerant satisfies the requirement, the operation of the recovery mode may be stopped, and the following operations are sequentially performed: closing the liquid valve; turning off the electric heating device A and/or the electric heating device B; stopping the operation of the compressor B and the external fan; closing the electromagnetic valve; and stopping the operation of the inner fan after waiting for n seconds.

After the recovery mode is finished, most of the refrigerant in the recovery equipment, the outdoor unit, the gas fluorine pipe and the liquid fluorine pipe is recovered and returned to the indoor unit, and only a small amount of refrigerant gas is reserved on a pipeline between the liquid valve and the A/B/C outlet of the one-way valve, and is usually within the allowable error of the filling quantity of the indoor unit.

In the present disclosure, a manually or automatically controlled valve may be used at the interface a/B/C/D/E/F or the like.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention. The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that modifications and variations can be made without departing from the technical principles of the present invention, and these modifications and variations should also be regarded as the scope of the invention.

Claims (10)

1. A refrigerant recovery system for refrigeration plant test, its characterized in that: comprising the following steps:

a compressor A (1), a condenser (3), an oil separator A (6), a first pipeline (101) and a second pipeline (102), wherein one end of the first pipeline (101) can be communicated with the oil separator A (6), the other end of the first pipeline can be communicated with the exhaust end of the compressor A (1), and one end of the second pipeline (102) can be communicated with the first pipeline (101), and the other end of the second pipeline can be communicated with one end of the condenser (3);

the condenser also comprises an expansion valve (5) and a fifth pipeline (105), one end of the fifth pipeline (105) can be communicated with the other end of the condenser (3), the other end can be communicated with the expansion valve (5),

the heat exchanger further comprises a compressor B (9), a heat exchanger (2) and an eighth pipeline (108), one end of the eighth pipeline (108) can be communicated with the oil separator A (6), the other end of the eighth pipeline is communicated with the air inlet end of the compressor B (9) so as to allow fluid to flow from the oil separator A (6) to the compressor B (9) in a recovery mode of a recovery system, the air outlet end of the compressor B (9) is also communicated with an eleventh pipeline (111), a part of pipe section of the fifth pipeline (105) is penetrated into the heat exchanger (2), and a part of pipe section of the eleventh pipeline (111) is penetrated into the heat exchanger (2) so as to heat and heat the refrigerant in the fifth pipeline (105) by the refrigerant in the eleventh pipeline (111) at the heat exchanger (2).

2. The refrigerant recovery system for testing a refrigeration device according to claim 1, wherein:

when the compressor A (1) is started, a refrigeration equipment test mode is operated, and at the moment, a mixture of the refrigerant and the lubricating oil discharged from the exhaust end of the compressor A (1) enters the oil separator A (6) through the first pipeline (101) to realize oil-gas separation; when the compressor A (1) is turned off, a recovery mode of a recovery system is operated, wherein a mixture of the refrigerant and the lubricating oil in the condenser (3) can enter the oil separator A (6) through the second pipeline (102) to realize oil-gas separation.

3. The refrigerant recovery system for testing a refrigeration device according to claim 1 or 2, wherein:

the heat exchanger (2) is a sleeve heat exchanger and comprises a sleeve, part of pipe sections of the fifth pipeline (105) and the eleventh pipeline (111) are respectively arranged in the sleeve in a penetrating way, and an electric heating device A (191) is further arranged on the sleeve so as to heat the refrigerant in the fifth pipeline (105); and/or an electric heating device B (192) is also arranged on a part of the pipe section of the fifth pipeline (105) which does not penetrate through the heat exchanger (2) so as to heat the refrigerant in the fifth pipeline (105).

4. A refrigerant recovery system for testing a refrigeration device according to claim 2 or 3, wherein:

a fourth pipeline (104), one end of the fourth pipeline (104) is connected to the inside of the oil separator A (6), and the other end of the fourth pipeline is communicated with the second pipeline (102) so as to allow fluid to flow from the oil separator A (6) to the second pipeline (102) when in a refrigeration equipment test mode;

and an eighth pipeline (108), wherein one end of the eighth pipeline (108) is communicated with the fourth pipeline (104), the other end of the eighth pipeline is communicated with the air inlet end of the compressor B (9) so as to allow fluid to flow from the oil separator A (6) to the compressor B (9) in a recovery mode of a recovery system, and a control valve (18) is arranged on the eighth pipeline (108).

5. The refrigerant recovery system for testing a refrigeration device according to claim 4, wherein:

the first pipeline (101) is connected with the second pipeline (102) at a first position (11), the fourth pipeline (104) is connected with the second pipeline (102) at a second position (12), a pipe section of the second pipeline (102) between the first position (11) and the second position (12) is a third pipeline (103), a one-way valve E (75) is arranged on the third pipeline (103), and the one-way valve E (75) can only allow refrigerant to flow from the second pipeline (102) to the first pipeline (101);

The eighth pipeline (108) is connected with the fourth pipeline (104) at a third position (13), a one-way valve D (74) is arranged on the fourth pipeline (104) and positioned on a pipe section between the third position (13) and the second position (12), and the one-way valve D (74) can only allow the refrigerant to flow from the fourth pipeline (104) to the second pipeline (102).

6. The refrigerant recovery system for testing a refrigeration device according to claim 4, wherein:

the system further comprises an oil separator B (10), a second throttling device (82), a ninth pipeline (109) and a tenth pipeline (110), wherein one end of the ninth pipeline (109) is communicated with the exhaust end of the compressor B (9), the other end of the ninth pipeline is communicated with the inside of the oil separator B (10), one end of the tenth pipeline (110) is communicated with the inside of the oil separator B (10), the other end of the tenth pipeline is communicated with the eighth pipeline (108), the joint position of the tenth pipeline (110) and the eighth pipeline (108) is a sixth position (16), and the sixth position (16) is located between the control valve (18) and the compressor B (9); the second throttling device (82) is arranged on the tenth pipeline (110); the eleventh pipeline (111) is communicated with the air outlet of the oil separator B (10).

7. The refrigerant recovery system for testing a refrigeration device according to claim 6, wherein:

the system further comprises an evaporator (4), a sixth pipeline (106) and a seventh pipeline (107), wherein one end of the sixth pipeline (106) is communicated with the expansion valve (5), the other end of the sixth pipeline is communicated with the evaporator (4), one end of the seventh pipeline (107) is communicated with the inside of the oil separator A (6), and the other end of the seventh pipeline is communicated with the fifth pipeline (105); the air outlet of the oil separator B (10) is communicated with the seventh pipeline (107) through the eleventh pipeline (111).

8. The refrigerant recovery system for testing a refrigeration device according to claim 7, wherein:

the eleventh pipeline (111) is connected with the seventh pipeline (107) at a fourth position (14), a one-way valve B (72) is arranged on the eleventh pipeline (111) and on a pipe section between the heat exchanger (2) and the fourth position (14), and the one-way valve B (72) can only allow the refrigerant to flow from the eleventh pipeline (111) to the seventh pipeline (107);

the fifth pipeline (105) is connected with the seventh pipeline (107) at a fifth position (15), a one-way valve C (73) is arranged on the fifth pipeline (105) and positioned on a pipe section between the heat exchanger (2) and the fifth position (15), and the one-way valve C (73) can only allow the refrigerant to flow from the fifth pipeline (105) to the expansion valve (5);

The seventh pipeline (107) is provided with a first throttling device (81) and a one-way valve A (71), the first throttling device (81) and the one-way valve A (71) are arranged between the oil separator A (6) and the fourth position (14), and the one-way valve A (71) can only allow fluid to flow from the oil separator A (6) to the fifth pipeline (105).

9. The refrigerant recovery system for testing a refrigeration device according to claim 8, wherein:

the first pipeline (101) is further provided with a gas valve (13 '), an interface A (141) and an interface C (143), and a liquid valve (15'), an interface B (142) and an interface D (144) are arranged on the fifth pipeline (105) and between the fifth position (15) and the expansion valve (5); an interface E (145) is arranged on the second pipeline (102), and an interface F (146) is arranged on the fifth pipeline (105) and positioned between the fifth position (15) and the condenser (3); a fluorine injection nozzle (16') is arranged between the evaporator (4) and the compressor A (1).

10. A control method of a refrigerant recovery system for a refrigeration equipment test according to any one of claims 4 to 9, characterized in that: comprising the following steps:

judging, namely judging whether the operation mode required by the refrigerant recovery system is a refrigeration equipment test mode or a recovery mode of the recovery system;

A control step of controlling the compressor A (1) to be opened, controlling the compressor B (9) to be closed and controlling the control valve (18) to be closed when the operation mode required by the refrigerant recovery system needs to be operated in a refrigeration equipment test mode; when the operation mode required by the refrigerant recovery system needs to be operated in the recovery mode of the recovery system, the compressor A (1) is controlled to be closed, the compressor B (9) is controlled to be opened, and the control valve (18) is controlled to be opened.