Refrigerating system with refrigerant redundancy adjusting function and control method

Abstract

The invention provides a refrigerating system with a refrigerant redundancy adjusting function and a control method.The refrigerating system comprises a fluorine pump, a liquid storage tank, an evaporator and a balance pipe, the liquid storage tank comprises an outer cylinder and an inner cylinder, the inner cylinder is located on the inner periphery of the outer cylinder, and a first communicating hole is formed in the cylinder wall of the inner cylinder so that the interior of the inner cylinder can communicate with the interior of the outer cylinder; the fluorine pump is communicated between the interior of the outer barrel and the evaporator, one end of the balance pipe is communicated to the upper end of the interior of the inner barrel, the other end of the balance pipe is communicated to the outlet end of the evaporator, and the balance pipe can introduce fluid into the interior of the inner barrel from the outlet end of the evaporator in a fluorine pump mode; at least part of liquid in the inner cylinder can be pressed into the outer cylinder through the first communicating hole; the device further comprises a compressor and an oil return assembly, and the oil return assembly can recover an oil-containing mixture in the liquid storage tank and can convey separated oil to the compressor. According to the invention, the problem of cavitation in a fluorine pump refrigeration mode can be solved, and the problem of unsmooth oil return when the compressor is started can also be solved.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and in particular to a refrigeration system with a refrigerant redundancy adjustment function and a control method. Background Art

[0002] With the extensive application of 4G and the gradual popularization of 5G, the heat generated by various data processing equipment is getting higher and higher, and data centers have higher and higher requirements for the cooling capacity and energy saving of air-conditioning equipment.

[0003] Using outdoor natural cold sources in transitional seasons and cold winters to cool the data center can significantly reduce the operating costs of air-conditioning equipment. A common method is to use fluorine pump air conditioners. In winter, the fluorine pump mode is enabled, the compressor is stopped, and the fluorine pump is used to drive the refrigerant to achieve heat pipe cooling operation, which greatly reduces the operating costs of the equipment.

[0004] The fluorine pump compression refrigeration system is a composite system. The fluorine pump heat pipe system and the compression refrigeration system share the evaporator and condenser, as well as some common refrigerant pipelines, system components, etc.

[0005] Since the heat load of the data center fluctuates with user usage and seasonal changes, more and more computer room air conditioners now use variable frequency technology to cope with the heat load fluctuations of the data center and ensure the constant temperature and humidity requirements of the data center. However, the change in the compressor frequency of the refrigeration system will cause the optimal refrigerant circulation volume to change. Generally, the higher the frequency, the greater the refrigerant circulation volume required. If the optimal refrigerant filling volume at 100% load is guaranteed during the design and development of the refrigeration system, since the optimal refrigerant filling volume at 75%, 50% or other low-frequency operating conditions is relatively small, the refrigerant inside the unit may accumulate liquid under low-frequency conditions, and the accumulated liquid is retained at the bottom of the heat exchanger, which is not conducive to heat exchange.

[0006] Considering the liquid height requirement at the suction port of the fluorine pump in the fluorine pump mode, the required refrigerant filling amount in the fluorine pump mode is usually relatively large. Therefore, the fluorine pump compression refrigeration system is likely to form refrigerant liquid retention under actual operating conditions. It is necessary to consider migrating the retained refrigerant to the liquid storage tank. Similarly, in the high-frequency compression refrigeration mode, the refrigerant liquid retained in the liquid storage tank should be released as soon as possible to participate in the system circulation operation. In addition, the fluorine pump refrigeration system also has the problem of cavitation caused by the low refrigerant liquid level in the liquid storage tank in the fluorine pump refrigeration mode.

[0007] The above are the differences caused by the optimal refrigerant circulation volume under different operating conditions. The problem of redundant adjustment of refrigerant needs to be solved. In addition, there are the following problems: Split air-conditioning equipment usually uses mechanically driven separate heat pipes, such as liquid pumps or air pumps and other fluorine pumps to drive heat pipes. When heat pipes and heat pumps share the same system, the throttling element and solenoid valve are usually designed in parallel. When the heat pump is running, the solenoid valve is closed, and the refrigerant is operated at a reduced pressure through the throttling element; when the heat pipe is running, the solenoid valve is opened, and the refrigerant mainly passes through the low-resistance solenoid valve to prevent the large resistance of the throttling element from consuming most of the gravity or the head of the fluorine pump.

[0008] Although the combination of heat pipes and heat pumps can reduce many parts when sharing the system, the debugging and optimization of the system is a very complex issue, and there are also some issues in the reliability of the system that cannot be ignored. For example, the refrigerant circulation volume in the compression refrigeration mode is much larger than the refrigerant circulation volume of the fluorine pump heat pipe circulation. Usually, a larger liquid storage tank is required in the system to adjust the difference in the refrigerant circulation volume between the two; the fluorine pump heat pipe operates at low outdoor temperatures, and the low-temperature liquid refrigerant and lubricating oil returned from the outdoor condenser are prone to oil stratification in the liquid storage tank. At this time, the lubricating oil is not easy to return to the newly started compressor with the refrigerant liquid, which is very likely to cause the compressor to lack oil during the startup phase, and in severe cases, the compressor will be damaged.

[0009] Another problem is that the refrigerant liquid that has not been completely evaporated by the evaporator enters the gas pipeline. The causes and technical background are as follows:

[0010] In air-conditioning refrigeration systems that do not use gas-liquid separators, preventing compressor liquid hammer is an important issue. The refrigerant liquid that has not completely evaporated in the evaporator enters the compressor along with the high-speed refrigerant gas, and the liquid hits the compression surface of the compressor, which can easily cause damage.

[0011] In order to prevent the liquid refrigerant in the evaporator from entering the compressor, the return gas main is usually connected to the highest possible liquid level in the gas collecting main of the evaporator. However, this can easily cause liquid refrigerant and lubricating oil to remain at the bottom of the gas collecting main. Because the refrigerant flow rate and velocity of the bottom branch are small and low, and it cannot carry enough liquid refrigerant and / or lubricating oil to flow upward, liquid refrigerant and some lubricating oil are likely to accumulate at the bottom of the gas collecting main after running for too long. When the height of these liquids gradually rises, the bottom branch is likely to form a liquid seal, and the refrigerant flow that can pass through is even less, resulting in the formation of "liquid storage" at the bottom of the evaporator. Obviously, these liquid refrigerants will also contain more lubricating oil, which can easily cause insufficient refrigerant circulation and insufficient oil return in the refrigeration system.

[0012] Existing patents 201920758930.1 and 201421133297.4 propose to connect the oil return pipe to the return gas main at the bottom of the evaporator's gas collecting pipe assembly, and use the pressure difference to suck the liquid retained at the bottom of the gas collecting pipe back to the compressor. However, there are some problems with these two patents: 1) After shutdown and static, the high and low pressures of the air conditioning refrigeration system will gradually achieve pressure balance, and the high-pressure end will squeeze the liquid refrigerant to accumulate in the evaporator. The refrigerant liquid at the bottom of the evaporator is easy to return directly to the compressor suction pipe through the oil return pipe, and even reach the compressor oil pool. During the next startup process, the compressor will start with liquid and be prone to liquid hammer, etc.; 2) The diameter of the oil return pipe is specified, but the length design of the oil return pipe is not mentioned. Only the diameter design principle of the oil return pipe is proposed. In actual design, the specification and length of the oil return pipe need to be determined based on the pressure difference and the size of the reflux volume. The smaller the diameter of the oil return pipe or the longer the oil return pipe, the smaller the reflux volume will be, and safe reflux may not be achieved, which will eventually cause the refrigerant liquid and lubricating oil to accumulate at the bottom of the evaporator.

[0013] In the fluorine pump refrigeration mode, the refrigerant liquid that has not been completely evaporated in the evaporator enters the gas pipeline between the evaporator and the condenser and is prone to form a "liquid seal" phenomenon, causing the gas flow resistance in these gas pipelines to increase and even affect the circulation of the gas, thereby causing the fluorine pump head to increase, the system energy efficiency ratio to decrease, the system performance to decrease and other problems. Therefore, it is also necessary to guide the refrigerant liquid at the evaporator outlet as much as possible and return it to the liquid pipeline.

[0014] In summary, it is urgent to solve the problem of redundant adjustment of refrigerant in the fluorine pump compression refrigeration system and solve the problem of refrigerant liquid circulation and system flow design that has not been completely evaporated at the evaporator outlet. This is a very necessary optimization design work for the efficient and stable operation of the fluorine pump compression refrigeration system.

[0015] Since the fluorine pump refrigeration system in the prior art has technical problems such as low refrigerant level in the liquid storage tank in the fluorine pump refrigeration mode causing cavitation, the present invention studies and designs a refrigeration system and control method with a refrigerant redundancy adjustment function. Summary of the invention

[0016] Therefore, the technical problem to be solved by the present invention is to overcome the defect of the fluorine pump compression refrigeration system in the prior art that the refrigerant liquid level in the liquid storage tank is low in the fluorine pump refrigeration mode, resulting in cavitation, thereby providing a refrigeration system and control method with a refrigerant redundancy adjustment function.

[0017] In order to solve the above problems, the present invention provides a refrigeration system with a refrigerant redundancy adjustment function, which comprises:

[0018] A fluorine pump, a liquid storage tank, an evaporator and a balance pipe, wherein the liquid storage tank comprises an outer cylinder and an inner cylinder, wherein the inner cylinder is located at the inner periphery of the outer cylinder, and a first connecting hole is provided on the cylinder wall of the inner cylinder so as to connect the interior of the inner cylinder with the interior of the outer cylinder, wherein the fluorine pump is connected between the interior of the outer cylinder and the evaporator, wherein one end of the balance pipe is connected to the inner upper end of the inner cylinder, and the other end of the balance pipe is connected to the outlet end of the evaporator, wherein in a fluorine pump mode, the balance pipe can introduce fluid from the outlet end of the evaporator into the interior of the inner cylinder so as to press at least part of the liquid in the inner cylinder into the outer cylinder through the first connecting hole so as to increase the liquid level in the outer cylinder;

[0019] It also includes a compressor and an oil return component, wherein the oil return component can recover the oil-containing mixture in the liquid storage tank and can transport the separated oil to the compressor.

[0020] In some embodiments,

[0021] The balancing pipe is provided with a one-way valve C, and the one-way valve C only allows the fluid to flow from the outlet end of the evaporator to the inner cylinder in the balancing pipe.

[0022] In some embodiments,

[0023] The float component is also included, and the float component is arranged inside the inner cylinder, and the float component floats in the liquid in the inner cylinder so as to rise or fall integrally with the liquid level height of the liquid. A lower limit plate is arranged below the float component, and a second connecting hole is also arranged on the lower limit plate. The second connecting hole passes through the upper and lower end surfaces of the lower limit plate. The liquid below the lower limit plate can enter the upper part of the lower limit plate through the second connecting hole and float the float component. When the liquid level above the lower limit plate drops to the height of the lower limit plate, the float component drops to connect with the second connecting hole and blocks the second connecting hole.

[0024] In some embodiments,

[0025] The position of the first connecting hole is lower than the height of the lower limit plate; the second connecting hole and the floating component are arranged opposite to each other in the vertical direction, and the lower end surface area of ​​the floating component is larger than the cross-sectional area of ​​the second connecting hole;

[0026] The lower limit plate is fixedly arranged on the inner wall of the inner cylinder, the outer peripheral wall of the lower limit plate is sealed and fixed to the inner peripheral wall of the inner cylinder, the lower limit plate can limit the downward movement of the floating component, and the lower limit plate is a single-hole plate, that is, the number of the second connecting hole is 1.

[0027] In some embodiments,

[0028] The lower end of the floating component is also connected to a lower connecting rod, which is inserted into the second connecting hole and can move up and down along the second connecting hole. The outer circumferential cross-sectional area of ​​the lower connecting rod is smaller than the cross-sectional area of ​​the second connecting hole, and the outer circumferential cross-sectional area of ​​the lower connecting rod is smaller than the lower end surface area of ​​the floating component.

[0029] In some embodiments,

[0030] An upper limit plate is also provided above the floating component, and the upper limit plate is fixedly provided on the inner wall of the inner cylinder, and the upper limit plate can limit the upward movement of the floating component;

[0031] The upper limit plate is provided with a third connecting hole, and the third connecting hole passes through the upper end surface and the lower end surface of the upper limit plate, so as to connect the space above the upper limit plate with the space below it, so that the liquid and / or gas below the upper limit plate can enter the upper part of the upper limit plate through the third connecting hole, and the liquid and / or gas above the upper limit plate can enter the lower part of the upper limit plate through the third connecting hole.

[0032] In some embodiments,

[0033] The upper limit plate is a porous plate, and the third connecting holes are multiple, and the multiple third connecting holes are distributed at intervals on the upper limit plate;

[0034] The upper end of the floating component is also connected to an upper connecting rod, which passes through the third connecting hole and can move up and down along the third connecting hole. The outer peripheral cross-sectional area of ​​the upper connecting rod is smaller than the cross-sectional area of ​​the third connecting hole.

[0035] In some embodiments,

[0036] The floating component is a floating plug, including an upper structure and a lower structure. The lower end of the upper structure is connected to the upper end of the lower structure. The upper structure is a conical structure, and the lower structure is a columnar structure. When there are both an upper connecting rod and a lower connecting rod, the upper end of the upper structure is connected to the lower end of the upper connecting rod, and the outer peripheral cross-sectional area of ​​the upper end of the upper structure is equal to the outer peripheral cross-sectional area of ​​the lower end of the upper connecting rod. The lower end of the lower structure is connected to the upper end of the lower connecting rod, and the outer peripheral cross-sectional area of ​​the lower end of the lower structure is larger than the outer peripheral cross-sectional area of ​​the upper end of the lower connecting rod.

[0037] In some embodiments,

[0038] The evaporator comprises an air collecting pipe, wherein the air collecting pipe is located at an outlet end of the evaporator, and the other end of the balance pipe is connected to an inner bottom end of the air collecting pipe.

[0039] In some embodiments,

[0040] It also includes a condenser, a liquid inlet pipe and a liquid outlet pipe, one end of the liquid inlet pipe is connected to the condenser, and the other end is connected to the inner top end of the outer cylinder of the liquid storage tank, so that the refrigerant after heat exchange in the condenser can be introduced into the liquid storage tank, one end of the liquid outlet pipe is connected to the inner bottom end of the outer cylinder of the liquid storage tank, and the other end is connected to one end of the fluorine pump.

[0041] In some embodiments,

[0042] It also includes a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a fifth pipeline, a throttle valve, a one-way valve A, a one-way valve B and an oil separator. The other end of the fluorine pump is connected to one end of the evaporator through the first pipeline, and the throttle valve is arranged on the first pipeline. One end of the second pipeline is connected to the liquid outlet pipe, and the other end is connected to a position on the first pipeline between the fluorine pump and the throttle valve. The one-way valve A that only allows fluid to flow from the liquid outlet pipe to the first pipeline is arranged on the second pipeline; the other end of the evaporator is connected to the third pipeline, and the third pipeline is connected to the suction end of the compressor through the fourth pipeline. The third pipeline is also connected to the exhaust end of the compressor through the fifth pipeline. The one-way valve B that only allows refrigerant fluid to flow from the suction end of the compressor to the exhaust end is arranged on the fifth pipeline, and the oil separator is also arranged between the exhaust end of the compressor and the condenser.

[0043] In some embodiments,

[0044] The other end of the balance pipe is connected to the third pipeline, or connected to the fifth pipeline; alternatively, the evaporator includes an air collecting pipe, which is located at the outlet end of the evaporator, and the other end of the balance pipe is connected to the inner bottom end of the air collecting pipe, and the inner top end of the air collecting pipe is connected to the third pipeline.

[0045] In some embodiments,

[0046] The oil return assembly includes a floating body, a hose and an oil return pipeline. The floating body is arranged inside the outer cylinder, and the floating body can float in the liquid in the outer cylinder so as to rise or fall integrally with the liquid level height. The floating body is provided with a liquid suction port so as to suck in the oil-containing mixture at the liquid surface. The upper end of the hose is connected to the floating body so as to be able to rise and fall integrally with the floating body so as to guide the oil-containing mixture sucked by the floating body. The lower end of the hose is connected to one end of the oil return pipeline, and the oil return pipeline extends out of the liquid storage tank so as to guide the oil-containing mixture to the suction end of the compressor.

[0047] In some embodiments,

[0048] The oil return pipeline is provided with a control valve, and the oil return pipeline is provided with a heating component, which can heat the mixed liquid of the refrigerant and the oil in the oil return pipeline to evaporate the refrigerant and separate the lubricating oil.

[0049] In some embodiments,

[0050] The heating component includes ribs and / or fins arranged on a partial pipe section on the oil return pipeline, so that the partial pipe section forms a finned tube and / or a finned tube, and the finned tube and / or the finned tube is arranged at the return air outlet of the evaporator.

[0051] In some embodiments,

[0052] The finned tubes and / or finned tubes are arranged outside and / or inside the evaporator. When the finned tubes and / or finned tubes are arranged inside the evaporator, the finned tubes and / or finned tubes are integrally formed with the heat exchange tubes of the evaporator.

[0053] In some embodiments,

[0054] It also includes a gas-liquid separator, which is arranged at the suction end of the compressor and communicated with the suction end, the other end of the oil return pipeline is connected to the interior of the gas-liquid separator, and the control valve is a solenoid valve.

[0055] The present invention also provides a control method for a refrigeration system having a function of adjusting the amount of redundant refrigerant as described above, comprising:

[0056] A detection step, detecting whether the compressor or the fluorine pump is stopped, and detecting the temperature of the liquid storage tank;

[0057] A determination step, determining the relationship between the temperature of the liquid storage tank and a preset temperature T0;

[0058] A control step, when the compressor is stopped or the fluorine pump is stopped, and the temperature of the liquid storage tank is continuously less than T0 for more than t0 time, controlling the control valve to open, wherein t0 is a preset time.

[0059] In some embodiments,

[0060] The control step controls the control valve to be open for a duration of t1, and closes the control valve after being opened for t1 time, and turns on the internal fan opposite to the evaporator and keeps running for t2; when the temperature condition of the liquid storage tank is met next time, the control valve and the internal fan are turned on in sequence, wherein t1 is the first preset time and t2 is the second preset time.

[0061] The refrigeration system and control method provided by the present invention with a function of adjusting the redundancy of refrigerant have the following beneficial effects:

[0062] 1. The present invention sets the liquid storage tank to have a structure including an outer cylinder and an inner cylinder, and the inner and outer cylinders are connected through a first connecting hole, and combined with a balance pipe, one end of the balance pipe is connected to the outlet end of the evaporator, and the other end is connected to the inner upper end of the inner cylinder, so that a fluid with a relatively high pressure (including refrigerant gas and / or liquid) can be introduced from the outlet end of the evaporator into the upper part of the inner cylinder in the fluorine pump refrigeration mode, so that the liquid in the inner cylinder is pressed into the outer cylinder through the first connecting hole by the pressure of the high-pressure fluid, so that the refrigerant liquid level of the outer cylinder of the liquid storage tank in the fluorine pump refrigeration operation mode is higher, that is, the liquid is higher when it is discharged. The degree is high, thereby ensuring that the fluorine pump has sufficient liquid suction height, effectively reducing the probability of cavitation, and solving the problem of cavitation in the fluorine pump refrigeration mode. In the compression refrigeration mode, due to the low pressure at the outlet of the evaporator, the fluid will not be introduced into the upper part of the inner cylinder through the balance pipe. Therefore, in the compression refrigeration mode, the liquid level of the inner cylinder rises and the liquid level in the outer cylinder drops. The higher-pressure gas in the upper part of the outer cylinder presses the liquid in the outer cylinder into the inner cylinder through the first connecting hole. The pressure changes at the top of the inner cylinder of the liquid storage tank in the compression refrigeration mode and the fluorine pump refrigeration mode are used to automatically adjust the optimal refrigerant circulation required in these two operating modes. The invention discloses a method for controlling the refrigerant level in the liquid storage tank by using the change of system pressure to realize automatic balancing and adjusting the change of the storage state of the refrigerant liquid inside the liquid storage tank, so that the inner cylinder of the liquid storage tank becomes a variable storage space for the refrigerant liquid. The system has high reliability and low cost, and does not require special control and adjustment. The liquid level in the liquid storage tank has an automatic balancing and adjusting function in different operation modes. At the same time, the problem of cavitation in the fluorine pump refrigeration mode and the problem of refrigerant redundancy caused by the difference in the refrigerant filling amount required in different operation modes of the fluorine pump compression refrigeration system are solved, and the problem of controlling the liquid level in the liquid storage tank is solved. In addition, the invention also solves the problem of controlling the liquid level in the liquid storage tank by setting the oil return component, so that the lubricating oil in the liquid storage tank can be sucked and recovered into the compressor in time in the shutdown state (preferably the shutdown state and the case where the oil and refrigerant are obviously stratified), so as to avoid the occurrence of oil shortage in the compressor and solve the problem of poor oil return when the compressor is started. It is further preferred to heat the oil return pipeline by a heating component, so that the refrigerant and the lubricating oil are effectively separated, so as to ensure that the lubricating oil with higher purity is recovered into the compressor, and the reliability of the compression refrigeration or fluorine pump refrigeration operation is not affected. The separation and recovery of the lubricating oil in the liquid storage tank under low temperature conditions is safe and reliable.

[0063] 2. The present invention provides a floating component and a lower limit plate in the inner cylinder, so that the floating component can float when the liquid level in the inner cylinder rises above the lower limit plate, and the floating component can be driven to continue to rise as the liquid level rises. This situation is applicable to the process when the fluorine pump refrigeration mode is converted into the compression refrigeration mode. When the liquid level in the inner cylinder drops, the floating component drops integrally with the liquid level. When the liquid level drops to the lower limit plate or even below, the floating component is limited by the lower limit plate and cannot continue to move downward. At the same time, the floating component blocks the second connecting hole, which can effectively prevent the gas above the lower limit plate from entering the lower part, or even entering the outer cylinder, thereby preventing the gas refrigerant from being discharged from the liquid storage tank to the fluorine pump or evaporator. The floating component and the lower limit plate can realize the function of passing liquid and blocking gas, and can automatically change the liquid level between the inner and outer cylinders according to different operating modes, different pressures and liquid level heights. The changes in system pressure and the buoyancy of the float plug are used to realize automatic balancing and adjusting to control the changes in the storage state of the refrigerant liquid inside the storage tank. In the fluorine pump refrigeration mode, the refrigerant liquid level in the outer cylinder of the storage tank is higher, thereby ensuring that the fluorine pump has sufficient liquid suction height to reduce the probability of cavitation. It has automatic balancing and adjusting functions in different operating modes to solve the problems of retention and release of refrigerant liquid and effectively solve the problem of controlling the liquid level in the storage tank.

[0064] 3. The present invention can also guide the unevaporated refrigerant liquid at the bottom of the gas collecting pipe by connecting the other end of the balance pipe to the inner bottom end of the gas collecting pipe at the outlet end of the evaporator, and guide the refrigerant liquid at the bottom of the gas collecting pipe of the evaporator in the fluorine pump refrigeration mode directly back to the liquid storage tank to participate in the system circulation as soon as possible, instead of entering the gas pipeline, thereby solving the problem of retention and release of the unevaporated refrigerant liquid at the evaporator outlet, and effectively solving the system design optimization problem of the flow path and circulation of these refrigerant liquids. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a system principle diagram of the fluorine pump double-circulation refrigeration system with the function of adjusting the redundant amount of refrigerant of the present invention (the system operates in the fluorine pump mode, and the float plug descends);

[0066] Figure 2 It is a system connection structure diagram of a fluorine pump double-circulation refrigeration system with a function of adjusting the redundant amount of refrigerant of the present invention (the system operates in a compression mode, and the float plug floats upward);

[0067] Figure 3 yes Figure 1 The enlarged structural diagram of the liquid storage tank part (under fluorine pump mode);

[0068] Figure 4 yes Figure 2 An enlarged view of the structure of the liquid storage tank part (under compression mode).

[0069] The reference numerals are as follows:

[0070] 1. Compressor; 2. Liquid storage tank; 3. Condenser; 4. Throttle valve; 5. Evaporator; 6. Outer cylinder; 7. Inner cylinder; 8. Floating component; 9. First connecting hole; 10. Fluorine pump; 11. One-way valve A; 12. One-way valve C; 13. Oil separator; 14. Internal fan; 15. One-way valve B; 16. Capillary tube; 17. External fan; 18. Lower limit plate; 19. Second connecting hole; 20. Lower connecting rod; 21. Upper limit plate; 22. Third connecting hole; 23. Upper connecting rod; 24. Upper structure; 25. Lower structure; 26. Floating body; 27. Hose; 28. Control valve; 29. ​​Ribbed tube and / or finned tube; 30. Gas-liquid separator;

[0071] 101, liquid inlet pipe; 102, liquid outlet pipe; 103, balance pipe; 104, gas collecting pipe; 201, first pipeline; 202, second pipeline; 203, third pipeline; 204, fourth pipeline; 205, fifth pipeline; 206, oil return pipeline. DETAILED DESCRIPTION

[0072] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all 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.

[0073] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. 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 "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0074] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood 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 ordinary technicians 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 authorization 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.

[0075] 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 devices or elements 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.

[0076] 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 other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0077] 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.

[0078] like Figure 1-4As shown, the present invention provides a refrigeration system with a refrigerant redundancy adjustment function, which includes:

[0079] A fluorine pump 10, a liquid storage tank 2, an evaporator 5 and a balance pipe 103, wherein the liquid storage tank 2 comprises an outer cylinder 6 and an inner cylinder 7, wherein the inner cylinder 7 is located on the inner periphery of the outer cylinder 6, and a first connecting hole 9 is provided on the cylinder wall of the inner cylinder 7 so as to connect the interior of the inner cylinder 7 with the interior of the outer cylinder 6, wherein the fluorine pump 10 is connected between the interior of the outer cylinder 6 and the evaporator 5, wherein one end of the balance pipe 103 is connected to the inner upper end of the inner cylinder 7, and the other end of the balance pipe 103 is connected to the outlet end of the evaporator 5, wherein in the fluorine pump mode, the balance pipe 103 can introduce fluid from the outlet end of the evaporator 5 into the interior of the inner cylinder 7 so as to press at least part of the liquid in the inner cylinder 7 into the outer cylinder 6 through the first connecting hole 9 so as to increase the liquid level in the outer cylinder 6;

[0080] It also includes a compressor 1 and an oil return assembly, wherein the oil return assembly can recover the oil-containing mixture (ie, oil-rich liquid) in the liquid storage tank 2 and can transport the separated oil to the compressor 1 .

[0081] The present invention sets the liquid storage tank to have a structure including an outer cylinder and an inner cylinder, and the inner and outer cylinders are connected through a first connecting hole, and combined with a balance pipe, one end of which is connected to the outlet end of the evaporator and the other end is connected to the inner upper end of the inner cylinder. In the fluorine pump refrigeration mode, a fluid with a relatively high pressure (including refrigerant gas and / or refrigerant liquid) can be introduced from the outlet end of the evaporator into the upper part of the inner cylinder, so that the liquid in the inner cylinder is pressed into the outer cylinder through the first connecting hole by the pressure of the high-pressure fluid, so that the refrigerant liquid level in the outer cylinder of the liquid storage tank in the fluorine pump refrigeration operation mode is higher, that is, The liquid outlet height is relatively high, thereby ensuring that the fluorine pump has sufficient liquid suction height, effectively reducing the probability of cavitation, and solving the problem of cavitation in the fluorine pump refrigeration mode. In the compression refrigeration mode, due to the low pressure at the outlet end of the evaporator, the fluid will not be introduced into the upper part of the inner cylinder through the balance pipe. Therefore, in the compression refrigeration mode, the liquid level in the inner cylinder rises and the liquid level in the outer cylinder drops. The higher-pressure gas in the upper part of the outer cylinder presses the liquid in the outer cylinder into the inner cylinder through the first connecting hole. The pressure changes at the top of the inner cylinder of the liquid storage tank in the compression refrigeration mode and the fluorine pump refrigeration mode are used to automatically adjust the pressure in these two operating modes. The optimal refrigerant circulation amount required does not need to increase the control hardware and control software. The change of system pressure is used to realize automatic balance adjustment to control the change of the storage state of the refrigerant liquid inside the liquid storage tank, so that the inner cylinder of the liquid storage tank becomes a variable storage space for the refrigerant liquid. The system has high reliability and low cost, and does not require special control and adjustment. The liquid level in the liquid storage tank has an automatic balance adjustment function in different operating modes. At the same time, the problem of cavitation in the fluorine pump refrigeration mode and the refrigerant redundancy problem caused by the difference in the refrigerant filling amount required in different operating modes of the fluorine pump compression refrigeration system are solved, and the control problem of the liquid level in the liquid storage tank is solved; and the present invention also solves the problem of controlling the liquid level in the liquid storage tank through the setting of the oil return component, preferably in the shutdown state (preferably the shutdown state and the case where the oil and refrigerant are obviously stratified) The lubricating oil in the liquid storage tank can be sucked and recovered to the compressor in time to avoid the compressor from lacking oil. It is further preferred to heat the oil return pipeline through a heating component to effectively separate the refrigerant and the lubricating oil, ensure that the lubricating oil with higher purity is recovered to the compressor, and does not affect the reliability of compression refrigeration or fluorine pump refrigeration operation. The separation and recovery of the lubricating oil in the liquid storage tank under low temperature conditions is safe and reliable.

[0082] like Figure 1 and Figure 3 As shown, the liquid storage tank 2 of the present invention preferably includes a liquid inlet pipe 101, a liquid outlet pipe 102 and a cylinder body; the liquid storage tank cylinder body is composed of an inner cylinder 7 and an outer cylinder 6 structure, the tops of the inner cylinder 7 and the outer cylinder 6 are preferably fixedly sealed and connected, the bottoms of the inner cylinder 7 and the outer cylinder 6 are preferably fixedly sealed and connected, and at least one first connecting hole 9 is opened on the bottom end side of the inner cylinder 7, and the inner cylinder 7 and the outer cylinder 6 can only be connected by relying on the first connecting hole 9.

[0083] The liquid storage tank of the present invention also includes a balance pipe 103, which is located at the top of the liquid storage tank and preferably continuously passes through the top of the outer cylinder 6 and the inner cylinder 7, so that the inner cylinder 7 is directly connected to the outside of the liquid storage tank through the balance pipe 103; the balance pipe 103 is preferably welded and sealed between the outer cylinder 6 and the inner cylinder 7.

[0084] In some embodiments,

[0085] The balancing pipe 103 is provided with a one-way valve C12 , and the one-way valve C12 only allows the fluid to flow from the outlet end of the evaporator 5 to the inner cylinder 7 in the balancing pipe 103 .

[0086] The present invention provides a one-way valve C on the balancing pipe, and the one-way valve C only allows the fluid to flow from the outlet end of the evaporator to the inner cylinder, thereby effectively preventing the gas inside the inner cylinder from flowing out to the outlet end of the evaporator through the balancing pipe, preventing the refrigerant liquid or gas from being pressed out through the balancing pipe due to the pressure of the outer cylinder being higher than the pressure of the evaporator outlet end in the compression refrigeration mode, avoiding the situation where the refrigerant does not pass through the evaporator and causing the evaporator to short-circuit, avoiding the decline in refrigeration performance, and ensuring that the refrigeration mode can operate reliably and stably.

[0087] like Figure 1 As shown, the fluorine pump compression refrigeration system including the novel liquid storage tank also includes a balance pipe, which is connected to the outlet of the evaporator and the balance pipe inlet of the liquid storage tank. A one-way valve C is provided on the balance pipe, and the flow direction of the one-way valve C only allows the refrigerant to flow from the outlet of the evaporator to the balance pipe of the liquid storage tank and enter the inner cylinder space of the liquid storage tank;

[0088] In some embodiments,

[0089] The inner cylinder 7 further includes a floating component 8, which is arranged inside the inner cylinder 7 and floats in the liquid in the inner cylinder 7 so as to rise or fall integrally with the liquid level. A lower limit plate 18 is arranged below the floating component 8, and a second connecting hole 19 is also arranged on the lower limit plate 18. The second connecting hole 19 passes through the upper and lower end surfaces of the lower limit plate 18. The liquid below the lower limit plate 18 can enter the upper part of the lower limit plate 18 through the second connecting hole 19 and float the floating component 8. When the liquid level above the lower limit plate 18 drops to the height of the lower limit plate 18, the floating component 8 drops to connect with the second connecting hole 19 and blocks the second connecting hole 19.

[0090] The present invention provides a floating component and a lower limit plate in the inner cylinder, so that the floating component can float when the liquid level in the inner cylinder rises above the lower limit plate, and the floating component can be driven to continue to rise as the liquid level rises. This situation is applicable to the process when the fluorine pump refrigeration mode is converted into the compression refrigeration mode. When the liquid level in the inner cylinder drops, the floating component drops integrally with the liquid level. When the liquid level drops to the lower limit plate or even below, the floating component is limited by the lower limit plate and cannot continue to move downward. At the same time, the floating component blocks the second connecting hole, which can effectively prevent the gas above the lower limit plate from entering the lower part, or even entering the outer cylinder, thereby preventing the gas refrigerant from being discharged from the liquid storage tank to the fluorine pump or the evaporator. In order to ensure normal and effective refrigeration, the floating component and the lower limit plate realize the function of passing liquid and blocking gas, and can automatically realize the change of the liquid level height between the inner and outer cylinders according to different operating modes, different pressures and liquid level heights. The change of system pressure and the buoyancy of the float plug are used to realize automatic balance and adjustment to control the change of the storage state of the refrigerant liquid inside the liquid storage tank. In the fluorine pump refrigeration mode, the refrigerant liquid level of the outer cylinder of the liquid storage tank is higher, thereby ensuring that the fluorine pump has sufficient liquid suction height to reduce the probability of cavitation. It has automatic balance and adjustment function in different operating modes, solves the problem of retention and release of refrigerant liquid, and effectively solves the problem of liquid level control in the liquid storage tank.

[0091] In some embodiments,

[0092] The position of the first connecting hole 9 is lower than the height of the lower limit plate 18 ; the second connecting hole 19 is arranged opposite to the floating component 8 in the vertical direction, and the lower end surface area of ​​the floating component 8 is larger than the cross-sectional area of ​​the second connecting hole 19 .

[0093] The present invention sets the first connecting hole at a height lower than the lower limit plate, so that the refrigerant liquid inside the outer cylinder can enter the lower limit plate of the inner cylinder through the first connecting hole. Then, as the liquid level in the inner cylinder rises, the liquid passes through the second connecting hole of the lower limit plate and pushes the float plug to float upward, thereby realizing the function and effect of liquid passing upward. The second connecting hole is opposite to the floating component in the vertical direction and the lower end area of ​​the floating component is larger than the area of ​​the second connecting hole, which can ensure that the floating component can completely block the second connecting hole when moving downward, thereby preventing the gas above from entering the lower limit plate when the liquid level in the inner cylinder drops below the lower limit plate, thereby preventing the gas from entering the outer cylinder and preventing the gas from entering the evaporator and causing the refrigeration performance to decrease.

[0094] In some embodiments,

[0095] The lower limit plate 18 is fixedly arranged on the inner wall of the inner tube 7, and the outer peripheral wall of the lower limit plate 18 is sealed and fixed to the inner peripheral wall of the inner tube 7. The lower limit plate 18 can limit the downward movement of the floating component 8. The lower limit plate 18 is a single-hole plate, that is, the number of the second connecting hole 19 is 1.

[0096] The lower limit plate of the present invention is preferably fixed to the inner wall of the inner cylinder, so that when the floating part moves up and down, the fixed lower limit plate is used to limit the downward movement of the floating part, and the lower limit plate of the present invention is further preferably a single-hole plate, that is, the number of the second connecting hole is 1, so that it can be ensured that when the liquid level rises, the fluid through the single second connecting hole can push the floating part to move upward and allow the fluid to enter the upper part of the lower limit plate, and it can also be ensured that when the liquid level drops, the floating part can completely block the upper and lower spaces of the lower limit plate through the single second flow hole, effectively realizing the function of liquid passing and gas blocking, avoiding gas from entering the lower part of the lower limit plate and then entering the outer cylinder, and further preventing gas from entering the evaporator and causing the refrigeration performance to decrease; the outer peripheral wall of the lower limit plate 18 is sealed and fixed to the inner peripheral wall of the inner cylinder 7 (for example, welding technology is adopted to ensure that the second connecting hole 19 is the only channel of the lower limit plate 18), so that the liquid below the lower limit plate can only enter the upper part through the second connecting hole, and the liquid above can only enter the lower part through the second connecting hole, thereby improving the gas blocking effect of the floating part and improving the function of liquid passing and gas blocking.

[0097] In some embodiments,

[0098] The lower end of the floating component 8 is also connected to a lower connecting rod 20, which is inserted into the second connecting hole 19 and can move up and down along the second connecting hole 19. The outer peripheral cross-sectional area of ​​the lower connecting rod 20 is smaller than the cross-sectional area of ​​the second connecting hole 19, and the outer peripheral cross-sectional area of ​​the lower connecting rod 20 is smaller than the lower end surface area of ​​the floating component 8.

[0099] The present invention preferably connects a lower connecting rod to the lower end of the floating component, and the lower connecting rod can be inserted into the second connecting hole to guide and limit the up and down movement of the floating component, thereby preventing the floating component from moving in the horizontal direction or tilting, ensuring that the floating component can always move in the vertical direction and thus can block the second connecting hole, thereby realizing the function of liquid passing and gas blocking. The outer peripheral cross-sectional area of ​​the lower connecting rod is preferably smaller than the cross-sectional area of ​​the second connecting hole, thereby ensuring that it can move smoothly in the second connecting hole without generating resistance.

[0100] In some embodiments,

[0101] An upper limit plate 21 is further provided above the floating component 8 . The upper limit plate 21 is fixedly provided on the inner wall of the inner tube 7 . The upper limit plate 21 can limit the upward movement of the floating component 8 .

[0102] The present invention further provides an upper limit plate above the floating component, and the upper limit plate is fixed on the inner wall of the inner tube, so as to effectively limit the upward movement of the floating component, thereby preventing the floating component from moving upward too far and causing the lower connecting rod to fall out of the second connecting hole, thereby ensuring that the floating component can move normally and reliably in the vertical direction.

[0103] In some embodiments,

[0104] The upper limit plate 21 is provided with a third connecting hole 22, and the third connecting hole 22 passes through the upper end surface and the lower end surface of the upper limit plate 21, so as to connect the space above the upper limit plate 21 with the space below it, so that the liquid and / or gas below the upper limit plate 21 can enter the upper part of the upper limit plate 21 through the third connecting hole 22, and the liquid and / or gas above the upper limit plate 21 can enter the lower part of the upper limit plate 21 through the third connecting hole 22.

[0105] The present invention also enables the refrigerant liquid and / or gas below the upper limit plate to enter the upper part through the third connecting hole, and the refrigerant liquid and / or gas above the upper limit plate to enter the lower part through the third connecting hole, through the third connecting hole provided on the upper limit plate, so that the refrigerant liquid can enter the upper part of the upper limit plate when the liquid level rises, and the refrigerant liquid can enter the lower part of the upper limit plate when the liquid level drops.

[0106] In some embodiments,

[0107] The upper limit plate 21 is a porous plate, and there are a plurality of third communication holes 22 , which are distributed at intervals on the upper limit plate 21 .

[0108] The upper limit plate of the present invention is preferably a porous plate, that is, the insertion of the upper connecting rod into one of the third connecting holes will not affect the passage of the refrigerant fluid through the other third connecting holes, ensuring the normal and effective flow of the refrigerant liquid from the top to the bottom or from the bottom to the top of the upper limit plate.

[0109] The inner cylinder of the liquid storage tank of the present invention is preferably horizontally fixed with a low-position single-hole plate (lower limit plate 18) and a high-position porous plate (upper limit plate 21). The single-hole plate and the porous plate are preferably welded and sealed to the wall of the inner cylinder. A flow hole (second connecting hole 19) located in the same vertical line is provided in the middle position of the single-hole plate and the porous plate. The porous plate has at least another flow hole (third connecting hole 22). The third connecting hole 22 is preferably as close to the edge of the porous plate as possible, that is, close to the wall of the inner cylinder (to prevent it from being blocked by the floating plug after floating up), so the porous plate has at least two third connecting holes 22.

[0110] The bottom end surface of the low-position single-hole plate of the present invention is higher than the first connecting hole 9 on the bottom side wall of the inner cylinder; the high-position multi-hole plate is higher than the low-position single-hole plate and preferably ensures that the two are in a horizontal parallel spacing state;

[0111] In some embodiments,

[0112] The upper end of the floating component 8 is also connected to an upper connecting rod 23, which is inserted into the third connecting hole 22 and can move up and down along the third connecting hole 22. The outer peripheral cross-sectional area of ​​the upper connecting rod 23 is smaller than the cross-sectional area of ​​the third connecting hole 22.

[0113] The present invention further adopts the structure of the upper connecting rod, which is inserted into the third connecting hole, and can guide and limit the upper end of the floating component, so that the upper end of the floating component can continuously and effectively move in the vertical direction, avoiding its horizontal movement or tilting movement. The cross-sectional area of ​​the upper connecting rod is smaller than the cross-sectional area of ​​the third connecting hole, which can ensure that the upper connecting rod can move normally and smoothly in the third connecting hole.

[0114] In some embodiments,

[0115] The floating component 8 is a floating plug, including an upper structure 24 and a lower structure 25. The lower end of the upper structure 24 is connected to the upper end of the lower structure 25. The upper structure 24 is a conical structure, and the lower structure 25 is a columnar structure. When there are both an upper connecting rod 23 and a lower connecting rod 20, the upper end of the upper structure 24 is connected to the lower end of the upper connecting rod 23, and the outer peripheral cross-sectional area of ​​the upper end of the upper structure 24 is equal to the outer peripheral cross-sectional area of ​​the lower end of the upper connecting rod 23. The lower end of the lower structure 25 is connected to the upper end of the lower connecting rod 20, and the outer peripheral cross-sectional area of ​​the lower end of the lower structure 25 is larger than the outer peripheral cross-sectional area of ​​the upper end of the lower connecting rod 20.

[0116] This is the preferred structural form of the floating component of the present invention, which is a floating plug structure composed of an upper structure and a lower structure. The upper structure is preferably a cone, and its upper end is connected to the lower end of the upper connecting rod. The outer peripheral cross-sectional areas of the two are preferably equal. The upper conical surface of the upper end of the upper structure can guide the refrigerant fluid (including liquid and / or gas) flowing from top to bottom downward so that it will not be deposited on the upper end surface of the floating component. The lower structure is preferably a column, and its lower end is connected to the lower connecting rod. The cross-sectional area of ​​the lower structure is larger than the cross-sectional area of ​​the upper end of the lower connecting rod, which can ensure that when the floating component moves downward to the lower limit plate, it can effectively block the second connecting hole on the lower limit plate through the large area of ​​the lower end surface, thereby realizing the function of liquid passage and gas blocking.

[0117] The present invention is further preferably that within the projection surface of the vertical plane, the upper structure is a triangle, and the lower structure is a rectangular structure. The upper structure is preferably a cone, and the lower structure is preferably a cylinder.

[0118] The upper and lower ends of the float inside the liquid storage tank of the present invention are also connected with thin rod-shaped components (upper connecting rod 23 and lower connecting rod 20), and the middle float is a large-section cylindrical structure; the thin rod components at the upper and lower ends of the float are respectively inserted into the middle flow holes of the porous plate and the single-hole plate, so that the float is clamped between the porous plate and the single-hole plate and can float up or down freely while being unable to escape from the single-hole plate and / or the porous plate.

[0119] The lower end surface of the float is preferably a horizontal plane. When the float floats up and abuts against the lower end surface of the porous plate, the upper end surface of the float cannot completely block the third connecting hole located at the edge of the porous plate. That is, the porous plate of the present invention can ensure that the upper and lower ends of the porous plate can be connected under any circumstances and cannot be closed or blocked.

[0120] The upper end surface of the floating plug of the present invention includes but is not limited to a horizontal surface, a conical surface, etc.; the horizontal cross-section of the floating plug includes but is not limited to a circle, a rectangle, a diamond, etc.;

[0121] The horizontal cross-sectional area of ​​the thin rod part at the lower end of the float is preferably smaller than the horizontal area of ​​the flow hole in the middle of the single-hole plate, and the horizontal cross-sectional area of ​​the thin rod part at the upper end of the float is smaller than the horizontal area of ​​the flow hole in the middle of the porous plate, so as to ensure that when the float rises and the lower end horizontal plane of its large-section column structure leaves the upper end surface of the single-hole plate, the refrigerant liquid can flow up and down through the flow holes of the single-hole plate. Therefore, when the float rises from the single-hole plate, the uppermost space of the inner cylinder can be connected with the outer cylinder space through the flow holes of the porous plate, the flow holes of the single-hole plate and the connecting holes on the bottom side wall of the inner cylinder in turn (such as Figure 4 The isolation state of the uppermost space of the inner cylinder and the outer cylinder space is as shown in Figure 3 As shown, at this time, the floating plug descends and abuts against the upper end surface of the single-hole plate.

[0122] In some embodiments,

[0123] The floating component 8 has a central axis, and the axes of the upper connecting rod 23 and the lower connecting rod 20 coincide with the central axis, and the axes of the upper structure 24 and the lower structure 25 also coincide with the central axis.

[0124] The present invention sets the axes of the upper connecting rod, the lower connecting rod, the upper structure and the lower structure of the floating component to be along the direction of the central axis, that is, the axes of the four coincide with each other, so that they can move up and down in an integrated manner in the vertical direction, and will not move horizontally or tilt even if they rotate, thereby ensuring that the float plug floats reliably and stably, and achieving the effect of liquid passing and gas blocking.

[0125] In some embodiments,

[0126] The evaporator 5 includes an air collecting pipe 104 , and the air collecting pipe 104 is located at the outlet end of the evaporator 5 . The other end of the balance pipe 103 is connected to the inner bottom end of the air collecting pipe 104 .

[0127] The present invention can also guide the unevaporated refrigerant liquid at the bottom of the gas collecting pipe by connecting the other end of the balance pipe to the inner bottom end of the gas collecting pipe at the outlet end of the evaporator, and guide the refrigerant liquid at the bottom of the gas collecting pipe of the evaporator in the fluorine pump refrigeration mode directly back to the liquid storage tank to participate in the system circulation as soon as possible, instead of entering the gas pipeline, thereby solving the problem of retention and release of the unevaporated refrigerant liquid at the evaporator outlet, and effectively solving the system design optimization problem of the flow path and circulation of these refrigerant liquids.

[0128] The present invention adds a new type of liquid storage tank in the fluorine pump compression refrigeration system. The liquid storage tank is designed as an inner and outer double cylinder structure, wherein the inner cylinder space and the outer cylinder space are only provided with a first connecting hole near the bottom connection, and the inner cylinder is provided with a horizontal low-position single-hole plate (lower limit plate) and a horizontal high-position multi-hole plate (upper limit plate) at intervals and both are higher than the first connecting hole, and a floating plug is provided between the two orifice plates and is restricted between the two orifice plates; the top of the inner cylinder is connected to the bottom of the gas collecting pipe of the evaporator, and a one-way valve is provided on the connecting pipeline to limit the fluid to flow from the evaporator to the inner cylinder of the liquid storage tank only.

[0129] The beneficial effects of the present invention are as follows: by utilizing the pressure changes at the top of the inner cylinder of the liquid storage tank in the compression refrigeration mode and the fluorine pump refrigeration mode, the optimal refrigerant circulation volume required in the two operating modes can be effectively adjusted without adding control hardware and control software. The changes in system pressure and the changes in the buoyancy of the float plug are utilized to realize automatic balancing and adjusting control of the changes in the storage state of the refrigerant liquid inside the liquid storage tank, so that the inner cylinder of the liquid storage tank becomes a variable containing space for the refrigerant liquid, and the refrigerant liquid level of the outer cylinder of the liquid storage tank in the fluorine pump refrigeration mode can be made higher, thereby ensuring that the fluorine pump has sufficient liquid suction height to reduce the probability of cavitation. The system has high reliability and low cost, does not require special control and adjustment, and the liquid level in the liquid storage tank has automatic balancing and adjustment functions under different operating modes.

[0130] The present invention solves the following technical problems:

[0131] 1) Cavitation problem in fluorine pump mode;

[0132] 2) The refrigerant redundancy problem caused by the difference in the refrigerant filling amount required under different operating modes of the fluorine pump compression refrigeration system solves the problem of controlling the liquid level in the liquid storage tank;

[0133] 3) Solve the problem of retention and release of refrigerant liquid that has not been completely evaporated at the evaporator outlet, and solve the system design optimization problem of the flow path and circulation of these refrigerant liquids.

[0134] In order to solve the problem 2 in the background technology, as Figure 2 As shown, a preferred embodiment of the present invention is that the inlet of the one-way valve C is connected to the bottom of the gas collecting pipe of the evaporator (that is, the balance pipe is connected to the bottom of the gas collecting pipe of the evaporator), so that the refrigerant liquid accumulated at the bottom of the gas collecting pipe can be smoothly discharged in the fluorine pump refrigeration mode and directly returned to the liquid storage tank to re-participate in the fluorine pump refrigeration cycle (that is, Figure 2 yes Figure 1 or draw part of the refrigerant fluid from the bottom of the gas collecting pipe into the upper space of the inner cylinder of the liquid storage tank, thereby forcing the refrigerant liquid in the inner cylinder space of the liquid storage tank to transfer to the outer cylinder space, and ensuring that the floating plug descends and abuts on the single-hole plate to prevent the refrigerant gas from entering the outer cylinder space (such as Figure 1 or Figure 3 shown).

[0135] In some embodiments,

[0136] It also includes a compressor 1, a condenser 3, a liquid inlet pipe 101 and a liquid outlet pipe 102, one end of the liquid inlet pipe 101 is connected to the condenser 3, and the other end is connected to the internal top end of the outer cylinder 6 of the liquid storage tank 2, so that the refrigerant after heat exchange in the condenser 3 can be introduced into the liquid storage tank 2, one end of the liquid outlet pipe 102 is connected to the internal bottom end of the outer cylinder 6 of the liquid storage tank 2, and the other end is connected to one end of the fluorine pump 10.

[0137] This is a further preferred structural form of the present invention. The liquid inlet pipe is connected to the top of the outer cylinder, and can introduce the refrigerant of the condenser after heat exchange into the outer cylinder of the liquid storage tank. The liquid outlet pipe is connected to the inner bottom of the outer cylinder, and can guide the refrigerant (preferably refrigerant liquid) in the outer cylinder to the fluorine pump. The function of the inner cylinder is to guide the refrigerant liquid below the outer cylinder to the inner cylinder, especially in the fluorine pump refrigeration mode, to increase the pressure at the upper end of the inner cylinder, thereby increasing the liquid volume and liquid height of the outer cylinder, ensuring that the liquid height is sufficient to prevent cavitation from occurring in the fluorine pump mode, and the liquid level heights of the inner and outer cylinders are almost equal in the compression mode, and the height of the liquid level of the outer cylinder can be automatically adjusted according to different modes. In the compression mode, the higher the compressor frequency, the higher the pressure at the liquid inlet pipe, and the lower the liquid level in the inner and outer cylinders. The liquid storage volume can be automatically adjusted according to different modes and compressor frequencies, thereby solving the refrigerant redundancy problem caused by the difference in the required refrigerant filling amount and solving the liquid level control problem in the liquid storage tank.

[0138] The liquid outlet pipe 102 of the present invention is preferably arranged at the bottom of the liquid storage tank; the liquid inlet pipe 101 is preferably arranged at the top of the outer cylinder space of the liquid storage tank 2 and / or the bottom of the liquid storage tank.

[0139] In some embodiments,

[0140] It also includes a first pipeline 201, a second pipeline 202, a third pipeline 203, a fourth pipeline 204, a fifth pipeline 205, a throttle valve 4, a one-way valve A11, a one-way valve B15 and an oil separator 13. The other end of the fluorine pump 10 is connected to one end of the evaporator 5 through the first pipeline 201. The throttle valve 4 is arranged on the first pipeline 201. One end of the second pipeline 202 is connected to the liquid outlet pipe 102, and the other end is connected to the position on the first pipeline 201 between the fluorine pump 10 and the throttle valve 4. The second pipeline 202 is provided with a valve that only allows The fluid flows from the liquid outlet pipe 102 to the one-way valve A11 of the first pipeline 201; the other end of the evaporator 5 is connected to the third pipeline 203, and the third pipeline 203 is connected to the suction end of the compressor 1 through the fourth pipeline 204. The third pipeline 203 is also connected to the exhaust end of the compressor 1 through the fifth pipeline 205. The fifth pipeline 205 is provided with the one-way valve B15 that only allows the refrigerant fluid to flow from the suction end of the compressor 1 to the exhaust end. The oil separator 13 is also provided between the exhaust end of the compressor 1 and the condenser 3.

[0141] This is a further preferred structural form of the refrigeration system of the present invention, that is, the one-way valve A is the pipeline for the circulation of refrigerant in the compression refrigeration mode, and the one-way valve B is the pipeline for the circulation of refrigerant in the fluorine pump mode. The one-way valve A effectively ensures that the refrigerant at the outlet end of the fluorine pump will not directly return to the inlet end of the fluorine pump, and the one-way valve B effectively ensures that the refrigerant at the outlet end of the compressor will not directly return to the inlet end of the compressor.

[0142] The present invention adds a novel liquid storage tank to the fluorine pump compression refrigeration system. The liquid storage tank is designed as an inner and outer double-cylinder structure, wherein the inner cylinder space and the outer cylinder space are only provided with a first connecting hole near the bottom connection, and the inner cylinder is provided with a horizontal low-position single-hole plate (lower limit plate) and a horizontal high-position multi-hole plate (upper limit plate) at intervals and both are higher than the first connecting hole (to ensure the normal floating of the float plug and the function of passing liquid and blocking gas), a float plug is provided between the two orifice plates and is restricted between the two orifice plates; the top of the inner cylinder is connected to the bottom of the gas collecting pipe of the evaporator, and a one-way valve is provided on the connecting pipeline to limit the fluid to flow from the evaporator to the inner cylinder of the liquid storage tank only.

[0143] Through the one-way valve between the evaporator and the liquid storage tank, in the compression refrigeration mode, the one-way valve is in a reverse high-pressure cut-off state, the float in the liquid storage tank rises under the action of the liquid buoyancy, and the liquid level in the inner cylinder of the liquid storage tank rises, so that more refrigerant liquid can be stored to meet the smaller refrigerant circulation volume required for the compression refrigeration mode; in the fluorine pump refrigeration mode, the one-way valve is in a forward high-pressure circulation state, and the refrigerant fluid at the bottom of the collecting pipe is filled into the inner cylinder of the liquid storage tank to force the refrigerant liquid to flow from the flow hole of the single-hole plate to the outer cylinder, so that the float drops and blocks the flow hole of the single-hole plate, thereby meeting the larger refrigerant circulation volume required for the fluorine pump refrigeration mode.

[0144] In summary, it can be seen that the present invention can realize the self-balancing adjustment function of the liquid level in the liquid storage tank to meet the optimal refrigerant circulation volume in different modes, and can also directly guide the refrigerant liquid at the bottom of the evaporator collecting pipe in the fluorine pump refrigeration mode back to the liquid storage tank as soon as possible to participate in the system circulation without entering the gas pipeline.

[0145] like Figure 1 and Figure 2 As shown, the fluorine pump compression refrigeration system is composed of a compressor 1, a condenser 3, a liquid storage tank 2, a fluorine pump 10, a throttle valve 4, and an evaporator 5 connected in sequence;

[0146] The fluorine pump compression refrigeration system also includes a one-way valve A11. The liquid outlet pipe 102 of the liquid storage tank 2 is connected to the inlet of the fluorine pump 10 and the inlet of the one-way valve A11. The outlet of the one-way valve A11 is connected between the outlet of the fluorine pump 10 and the inlet of the throttle valve 4. The flow direction of the one-way valve A11 is only allowed to be directed from the liquid outlet pipe 102 of the liquid storage tank 2 to the inlet of the throttle valve 4.

[0147] The fluorine pump compression refrigeration system also includes a one-way valve B15, which is connected in parallel to bypass the compressor. The inlet and outlet of the one-way valve B15 are respectively connected to the suction port and the exhaust port of the compressor 1. The flow direction of the one-way valve B15 is only allowed to be directed from the inlet of the compressor 1 to the outlet of the compressor 1.

[0148] The fluorine pump compression refrigeration system also includes an oil separator 13 and a capillary tube 16 for oil return. The oil separator 13 is connected between the exhaust port of the compressor 1 and the inlet of the condenser 3, the air inlet of the oil separator 13 is connected to the exhaust port of the compressor 1, the air outlet of the oil separator 13 is connected to the inlet of the condenser 3, and the capillary tube 16 is connected between the oil outlet of the oil separator 13 and the air intake port of the compressor 1.

[0149] In some embodiments,

[0150] The other end of the balance pipe 103 is connected to the third pipeline 203, or connected to the fifth pipeline 205; alternatively, the evaporator 5 includes an air collecting pipe 104, which is located at the outlet end of the evaporator 5, and the other end of the balance pipe 103 is connected to the inner bottom end of the air collecting pipe 104, and the inner top end of the air collecting pipe 104 is connected to the third pipeline 203.

[0151] This is the preferred connection position and connection method of the balance pipe of the present invention. The other end of the balance pipe is preferably connected to the third pipeline or the fifth pipeline, which can effectively introduce the fluid at the outlet end of the evaporator into the top of the inner cylinder, or the other end of the balance pipe is connected to the inner bottom end of the gas collecting pipe, which can guide the unevaporated refrigerant liquid at the bottom of the gas collecting pipe, and directly guide the refrigerant liquid at the bottom of the evaporator gas collecting pipe in the fluorine pump refrigeration mode back to the liquid storage tank to participate in the system circulation as soon as possible, instead of entering the gas pipeline, which solves the problem of retention and release of the refrigerant liquid that has not been completely evaporated at the evaporator outlet, and effectively solves the system design optimization problem of the flow path and circulation of these refrigerant liquids. The inner top end of the gas collecting pipe is connected to the third pipeline, which can guide the refrigerant gas after evaporation to the compressor suction port or enter the condenser through the third pipeline, to ensure that the compressor suction is free of liquid.

[0152] For ease of understanding and explanation, Figure 1 Shows the status of the liquid storage tank in the fluorine pump cooling mode (also refer to Figure 3 ), Figure 2 Shows the status of the liquid storage tank in compression cooling mode (also refer to Figure 4 ), the working principle of the fluorine pump compression refrigeration system and the circulating flow path and working status of the components of the refrigeration system are described as follows:

[0153] A) If Figure 1 As shown, the main refrigerant path of the fluorine pump refrigeration mode is: fluorine pump → throttle valve → evaporator → check valve B → oil separator → condenser → liquid storage tank → fluorine pump.

[0154] illustrate:

[0155] a1) Part of the refrigerant at the evaporator outlet will also pass through the gas-liquid separator and capillary tube into the oil separator and then into the condenser. That is to say, this flow path is in parallel with the flow path of the one-way valve B, but the refrigerant flow at the one-way valve B is larger, and the refrigerant flow at the flow path where the capillary tube is located can be ignored;

[0156] a2) When the fluorine pump is working, its outlet pressure is higher than the inlet pressure, that is, at this time, the one-way valve A is in the reverse high-pressure cut-off state, that is, the one-way valve A can prevent the refrigerant liquid at the outlet of the fluorine pump from directly short-circuiting back to the inlet of the fluorine pump;

[0157] a3) The outlet pressure of the fluorine pump is the highest pressure of the system, and the inlet pressure of the fluorine pump is the lowest pressure of the system. The pressure gradually decreases with the flow direction of the refrigerant. Because the pressure of the evaporator outlet is higher than the pressure at the top of the liquid storage tank, the one-way valve C is in a positive high-pressure flow state at this time. Therefore, part of the refrigerant at the bottom outlet of the evaporator's gas collecting pipe will flow from the one-way valve C into the inner cylinder of the liquid storage tank. If there is liquid flowing from the one-way valve C into the inner cylinder space of the liquid storage tank, when the refrigerant liquid flowing in is sufficient, the float will rise. At this time, the refrigerant liquid accumulated on the inner cylinder flows into the outer cylinder space from the flow hole of the single-hole plate. When the refrigerant liquid in the upper part of the inner cylinder is insufficient or even all refrigerant gas, the buoyancy of the float is insufficient, causing the float to drop until it blocks the flow hole of the single-hole plate, so the refrigerant gas in the upper part of the inner cylinder cannot enter the outer cylinder. Therefore, the float in the liquid storage tank has an automatic balancing and adjustment function in the fluorine pump refrigeration mode. Since most of the space in the inner cylinder is refrigerant gas, the amount of refrigerant liquid stored in the liquid storage tank will be less, that is, the amount of refrigerant circulation participating in the system operation will be more, thereby meeting the optimal refrigerant circulation volume requirement of the fluorine pump refrigeration mode; because the liquid storage tank basically only relies on the outer cylinder to participate in the refrigerant circulation at this time, the height of the refrigerant liquid level in the outer cylinder will be greater, which also meets the larger suction height for the safe operation of the fluorine pump, thereby reducing the probability of cavitation in the fluorine pump, and the operation of the fluorine pump is safer and more reliable.

[0158] B) Figure 2 As shown, the main refrigerant path of the compression refrigeration mode is: compressor → oil separator → condenser → liquid storage tank → one-way valve A → throttle valve → evaporator → gas-liquid separator → compressor.

[0159] illustrate:

[0160] b1) The lubricating oil separated in the oil separator is depressurized through the capillary tube under the pressure difference between high pressure and low pressure and returns to the compressor suction port. Sometimes a small amount of high-pressure refrigerant gas is depressurized through the capillary tube and returns to the compressor suction port, but it can basically be ignored;

[0161] b2) Some refrigerant liquid in the liquid storage tank outlet pipe will also flow through the gap of the impeller of the fluorine pump, that is, the one-way valve A and the fluorine pump are in parallel flow at this time, but the refrigerant liquid flow at the one-way valve A is larger, and the refrigerant liquid flow through the fluorine pump can be ignored;

[0162] b3) The pressure at the compressor exhaust port is the highest pressure in the system, and the pressure at the compressor suction port is the lowest pressure in the system. The pressure gradually decreases with the flow direction of the refrigerant. The inlet of the throttle valve is high pressure and the outlet is low pressure. Because the outlet of the one-way valve C is connected to the high-pressure liquid storage tank, and the inlet of the one-way valve C is connected to the gas collecting pipe of the low-pressure evaporator, the one-way valve C is in a reverse high-pressure cut-off state at this time. Therefore, the refrigerant liquid in the outer cylinder of the liquid storage tank can enter the inner cylinder to float the float plug. The refrigerant liquid in the outer cylinder passes through the connecting holes on the bottom side wall of the inner cylinder, the flow holes of the single-hole plate, and the flow holes of the multi-hole plate in turn into the upper space of the inner cylinder. Therefore, the refrigerant liquid level of the inner cylinder and the outer cylinder is consistent (U-tube communicating vessel principle), so that the liquid storage tank can store more refrigerant liquid in the compression refrigeration mode, that is, the refrigerant circulation volume participating in the system operation will be less, thereby meeting the optimal refrigerant circulation volume requirement of the compression refrigeration mode.

[0163] In some embodiments,

[0164] The oil return assembly includes a floating body 26, a hose 27 (i.e., a bendable flexible tube) and an oil return pipeline 206. The floating body 26 is arranged inside the outer tube 6, and the floating body 26 can float in the liquid in the outer tube 6 so as to rise or fall integrally with the liquid level height. The floating body 26 is provided with a liquid suction port so as to suck in the oil-containing mixture at the liquid surface (i.e., oil-rich liquid). The upper end of the hose 27 is connected to the floating body 26 so as to be able to rise and fall integrally with the floating body 26 so as to guide the oil-containing mixture sucked by the floating body 26. The lower end of the hose 27 is connected to one end of the oil return pipeline 206, and the oil return pipeline 206 extends out of the liquid storage tank 2 so as to guide the oil-containing mixture to the suction end of the compressor 1.

[0165] This is the preferred structural form of the oil return assembly of the present invention, which can float in the liquid (partly on the liquid surface and partly below the liquid surface) through the floating body. Preferably, its density is less than the density of the lubricating oil, so that the lubricating oil can be sucked from the liquid surface through the suction port. Moreover, through the structure of the hose, its upper end can be connected to the floating body as a whole and can float up and down as a whole, so as to guide the lubricating oil absorbed by the floating body downward into the oil return pipeline, and further guide it back to the compressor, thereby effectively recovering the lubricating oil in the liquid storage tank and delivering it to the compressor, thereby ensuring the normal and reliable operation of the compressor.

[0166] The floating body of the present invention is preferably a float, that is, the liquid storage tank 2 of the present invention also includes a float and a hose 27. The float is connected to the return oil pipeline 206 through the hose 27. The return oil pipeline 206 is arranged at the bottom of the liquid storage tank. The oil-rich liquid in the upper layer of the liquid storage tank flows out of the liquid storage tank 2 through the float, the hose 27 and the return oil pipeline 206; the float and the hose 27 are preferably made of low-density materials, and a liquid inlet is provided on the float to connect to the hose 27. The density of the float and the hose 27 is lower than the density of the lubricating oil at the highest design operating temperature of the unit (the density of the lubricating oil is usually negatively correlated with the temperature).

[0167] In some embodiments,

[0168] The oil return line 206 is provided with a control valve 28 , and the oil return line 206 is provided with a heating component, which can heat the mixture of refrigerant and oil in the oil return line 206 to evaporate the refrigerant and separate the lubricating oil.

[0169] The present invention can also achieve effective control of oil return through the control valve arranged on the oil return pipeline, especially the control valve can only be opened to achieve oil return under certain conditions (the condition is preferably in the shutdown state and the temperature of the liquid storage tank is at a low temperature for a certain period of time. At this time, the stratification of the lubricating oil and the refrigerant is obvious, and the lubricating oil can be sucked to obtain oil with higher purity), and further the mixture of the lubricating oil and the refrigerant can be heated by the setting of the heating component. Since the boiling point of the refrigerant is usually lower than that of the lubricating oil, the refrigerant is evaporated into a gaseous state, the lubricating oil and the refrigerant are separated, the lubricating oil is purified, and delivered to the compressor, to ensure that the compressor has enough lubricating oil when it is started next time, and it can start normally, and it can also ensure that the refrigerant is in the circulation loop to ensure an effective refrigeration cycle.

[0170] The oil return assembly of the present invention is provided with a low-density float and a matching hose in the outer cylinder space of the new liquid storage tank for collecting the oil-rich liquid on the upper layer of the liquid storage tank and sending it to the heating component under appropriate operating conditions. The heating component vaporizes the refrigerant in the oil-rich liquid, and the separated lubricating oil returns to the gas-liquid separator to wait for suction and recovery by the compressor.

[0171] The present invention aims at the oil stratification phenomenon in the liquid storage tank caused by the fluorine pump refrigeration operation, especially, and ensures that the stratified lubricating oil can be returned to the compressor oil pool in time when the compressor refrigeration is started, thereby ensuring the reliable operation of the compression refrigeration, and solves the problem of recovery control and separation of the lubricating oil and returning it to the compressor oil pool when the oil in the liquid storage tank of the fluorine pump compression double-circulation refrigeration unit is stratified under low temperature conditions.

[0172] In some embodiments,

[0173] The heating component includes fins and / or fins arranged on a partial pipe section on the oil return pipeline 206, so that the partial pipe section forms a finned tube and / or a finned tube 29, and the finned tube and / or the finned tube 29 is arranged at the return air outlet of the evaporator 5.

[0174] This is the preferred structural form of the heating component of the present invention, that is, the heating component includes ribs and / or fins, thereby forming rib tubes and / or fin tubes on the oil return pipeline, thereby enhancing heat exchange, especially arranging the rib tubes and / or fin tubes 29 at the return air inlet of the evaporator 5, and being able to use the hotter gas of the evaporator return air to heat the mixture of refrigerant and oil in the oil return pipeline to evaporate the refrigerant, thereby achieving the purpose of further separating the refrigerant and oil, improving the separation purity of the lubricating oil, and improving the oil return efficiency of the compressor return oil.

[0175] In some embodiments,

[0176] The finned tube and / or finned tube 29 is arranged outside and / or inside the evaporator 5. When the finned tube and / or finned tube 29 is arranged inside the evaporator 5, the finned tube and / or finned tube 29 is integrally formed with the heat exchange tube of the evaporator 5.

[0177] The finned tubes and / or finned tubes of the present invention can be located outside and / or inside the evaporator. These are two different ways of arranging the finned tubes and / or finned tubes of the present invention. As long as they are located at the return air inlet of the evaporator, the higher temperature gas at the return air inlet can be effectively used to heat the return oil pipeline. When the finned tubes and / or finned tubes are arranged inside the evaporator, they are preferably integrally formed with the heat exchange tubes of the evaporator to achieve one-piece manufacturing, but the refrigerant in the heat exchange tubes of the evaporator and the fluid in the finned tubes and / or finned tubes are not mixed and are not connected.

[0178] The present invention preferably provides a heating component on the oil return line 206, and the heating component is preferably provided at the return air port of the evaporator, so as to fully utilize the heat of the indoor hot air to heat the oil-rich liquid inside the heating component, so that the refrigerant in the oil-rich liquid evaporates and gasifies, thereby separating the lubricating oil. Figure 2 As shown, the heating component can be a heat exchange fin or fin arranged on the outer surface of the oil return pipe, that is, a fin tube and / or a fin tube are arranged in series on the oil return pipe, and the fin tube and / or the fin tube are arranged in the return channel of the hot air; the fin tube and / or the fin tube can be integrally formed with the evaporator, that is, a separate branch on the evaporator of the fin tube heat exchanger type is used to connect the oil return pipe, that is, the oil return port of the gas-liquid separator is connected to the upper end of the branch, and the other end of the branch is connected to the return pipe of the liquid storage tank, such as Figure 1 shown.

[0179] In some embodiments,

[0180] It also includes a gas-liquid separator 30, which is arranged at the suction end of the compressor 1 and communicated with the suction end. The other end of the return oil pipeline 206 is connected to the interior of the gas-liquid separator 30, and the control valve 28 is a solenoid valve.

[0181] The present invention preferably provides a gas-liquid separator, which is connected to the suction end of the compressor, and the oil return pipeline is connected to the interior of the gas-liquid separator, and the separated lubricating oil is guided to the gas-liquid separator. When the compressor is started, it sucks the fluid in the gas-liquid separator, thereby guiding the lubricating oil back to the compressor. The control valve of the present invention preferably adopts an electromagnetic valve to achieve precise control, and is further preferably a normally closed electromagnetic valve when the power is off.

[0182] The fluorine pump compression dual-cycle refrigeration unit of the present invention preferably further includes a gas-liquid separator 30, which is arranged between the top outlet of the gas collecting pipe 104 of the evaporator and the air intake port of the compressor 1;

[0183] The gas-liquid separator 30 preferably also has a lubricating oil return port, which is connected to the bottom end of the liquid storage tank 2 through an oil return pipeline 206 .

[0184] The present invention also provides a control method for a refrigeration system having a function of adjusting the amount of redundant refrigerant as described above, comprising:

[0185] A detection step, detecting whether the compressor or the fluorine pump is stopped, and detecting the temperature of the liquid storage tank 2;

[0186] A determination step, determining the relationship between the temperature of the liquid storage tank 2 and a preset temperature T0;

[0187] The control step is to control the control valve 28 to open when the compressor or the fluorine pump is stopped and the temperature of the liquid storage tank 2 is less than T0 for more than t0 time, wherein t0 is a preset time.

[0188] The present invention judges the operating state of the compressor and / or the fluorine pump, and when the compressor is stopped or the fluorine pump is stopped, and the temperature of the liquid storage tank 2 is continuously less than T0 for more than t0 time (oil refrigerant stratification is most likely to occur in this state, so the purity of the oil absorption and separation is higher and the efficiency is higher), controls the on and off of the oil return component to allow the oil-rich liquid in the upper layer of the low-temperature liquid storage tank to enter the heating component, and uses hot air to separate the refrigerant and lubricating oil. The system control is simple and reliable, does not affect the reliability of compression refrigeration or fluorine pump refrigeration operation, and the separation and recovery of the lubricating oil in the liquid storage tank under low temperature conditions is safe and reliable.

[0189] In some embodiments,

[0190] The control step controls the control valve 28 to be open for a duration of t1, and closes the control valve 28 after being opened for t1 time, and turns on the internal fan 14 opposite to the evaporator 5 and continues to operate for t2; when the temperature condition of the liquid storage tank is met next time, the control valve 28 and the internal fan 14 are turned on in sequence, wherein t1 is the first preset time and t2 is the second preset time.

[0191] The oil return control principle of the present invention is described as follows:

[0192] Under low temperature conditions, the refrigerant liquid and lubricating oil in the liquid storage tank will be stratified, and the low-density lubricating oil floats on the high-density refrigerant liquid, so the upper layer of the liquid storage tank is oil-rich liquid; the float and the hose are made of low-density materials, and the float is provided with a liquid inlet connected to the hose. The density of the float and the hose is lower than the density of the lubricating oil at the highest design operating temperature of the unit (the density of the lubricating oil is usually negatively correlated with the temperature);

[0193] 1) When the compressor or fluorine pump is shut down, if the temperature of the liquid storage tank is detected to be ≤T0 and the duration is t0 or above (the condition most likely to cause oil stratification), the solenoid valve is opened for t1, so that the oil-rich liquid in the upper layer of the liquid storage tank enters and fills the oil return pipe quantitatively under the action of gravity (because the solenoid valve opening time t1 is fixed);

[0194] 2) Close the solenoid valve and turn on the internal fan for a duration of t2, using the hot air in the room to heat the refrigerant liquid inside the heating component to evaporate into gas, and the lubricating oil is separated and retained in the heating component;

[0195] 3) The next time the conditions are met, the solenoid valve is opened, and the floating oil liquid continues to enter the oil return pipe, pushing the lubricating oil separated and retained in the heating component into the gas-liquid separator. The lubricating oil entering the gas-liquid separator waits to be sucked back into the oil pool of the compressor after the compressor is started.

[0196] The present invention continuously collects and separates lubricating oil and stores it in the gas-liquid separator under the fluorine pump refrigeration mode (for example, the fluorine pump is temporarily shut down for oil return), which does not affect the reliable operation of the fluorine pump refrigeration mode. More and more lubricating oil is accumulated in the gas-liquid separator waiting for the compressor to start and run, which can effectively ensure the reliability of the startup operation of the compressor; in the fluorine pump refrigeration mode, less and less lubricating oil flows in the system, and the refrigerant liquid flowing into the heating component after the solenoid valve is opened will be fully heated and vaporized, enter the condenser for cooling, and be liquefied and returned to the liquid storage tank. The refrigerant liquid will not accumulate in the gas-liquid separator. Therefore, the oil return control of the present invention is safe and reliable, and can fully ensure the oil return effect of the compressor.

[0197] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A refrigeration system with a function of adjusting the amount of redundant refrigerant, characterized in that: include: A fluorine pump (10), a liquid storage tank (2), an evaporator (5) and a balance pipe (103), wherein the liquid storage tank (2) comprises an outer cylinder (6) and an inner cylinder (7), wherein the inner cylinder (7) is located on the inner periphery of the outer cylinder (6), and a first connecting hole (9) is provided on the cylinder wall of the inner cylinder (7) so as to connect the interior of the inner cylinder (7) with the interior of the outer cylinder (6), wherein the fluorine pump (10) is connected between the interior of the outer cylinder (6) and the evaporator (5), and the balance pipe (103) is provided on the cylinder wall of the inner cylinder (7) so as to connect the interior of the inner cylinder (7) with the interior of the outer cylinder (6), wherein the fluorine pump (10) is connected between the interior of the outer cylinder (6) and the evaporator (5), and wherein the balance pipe (103) is provided on the cylinder wall of the inner cylinder (7) and the evaporator (5). One end of the balance tube (103) is connected to the upper end of the inner cylinder (7), and the other end of the balance tube (103) is connected to the outlet end of the evaporator (5). In the fluorine pump mode, the balance tube (103) can introduce fluid from the outlet end of the evaporator (5) into the interior of the inner cylinder (7), so as to press at least part of the liquid in the inner cylinder (7) into the outer cylinder (6) through the first connecting hole (9), so as to increase the liquid level in the outer cylinder (6); It also comprises a compressor (1) and an oil return assembly, wherein the oil return assembly can recover the oil-containing mixture in the liquid storage tank (2) and can transport the separated oil to the compressor (1).

2. The refrigeration system with a refrigerant redundancy adjustment function according to claim 1, characterized in that: The balancing pipe (103) is provided with a one-way valve C (12), and the one-way valve C (12) only allows the fluid to flow from the outlet end of the evaporator (5) to the inner cylinder (7) in the balancing pipe (103).

3. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 1, characterized in that: The invention also comprises a floating component (8), wherein the floating component (8) is arranged inside the inner cylinder (7), and the floating component (8) floats in the liquid in the inner cylinder (7) so as to be able to rise or fall integrally with the liquid level height. A lower limit plate (18) is arranged below the floating component (8), and a second connecting hole (19) is also arranged on the lower limit plate (18). The second connecting hole (19) passes through the upper and lower end surfaces of the lower limit plate (18). The liquid below the lower limit plate (18) can enter the upper part of the lower limit plate (18) through the second connecting hole (19) and float the floating component (8). When the liquid level above the lower limit plate (18) drops to the height of the lower limit plate (18), the floating component (8) drops to connect with the second connecting hole (19) and blocks the second connecting hole (19).

4. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 3, characterized in that: The position of the first connecting hole (9) is lower than the height of the lower limit plate (18); the second connecting hole (19) and the floating component (8) are arranged opposite to each other in the vertical direction, and the lower end surface area of ​​the floating component (8) is larger than the cross-sectional area of ​​the second connecting hole (19); The lower limit plate (18) is fixedly arranged on the inner wall of the inner cylinder (7), and the outer peripheral wall of the lower limit plate (18) is sealed and fixed to the inner peripheral wall of the inner cylinder (7). The lower limit plate (18) can limit the downward movement of the floating component (8). The lower limit plate (18) is a single-hole plate, that is, the number of the second connecting hole (19) is 1.

5. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 3, characterized in that: The lower end of the floating component (8) is also connected to a lower connecting rod (20), the lower connecting rod (20) is inserted into the second connecting hole (19) and can move up and down along the second connecting hole (19), the outer peripheral cross-sectional area of ​​the lower connecting rod (20) is smaller than the cross-sectional area of ​​the second connecting hole (19), and the outer peripheral cross-sectional area of ​​the lower connecting rod (20) is smaller than the lower end surface area of ​​the floating component (8).

6. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to any one of claims 1 to 5, characterized in that: An upper limit plate (21) is also provided above the floating component (8), and the upper limit plate (21) is fixedly arranged on the inner wall of the inner cylinder (7), and the upper limit plate (21) can limit the upward movement of the floating component (8); The upper limit plate (21) is provided with a third connecting hole (22), and the third connecting hole (22) passes through the upper end surface and the lower end surface of the upper limit plate (21), so as to connect the space above the upper limit plate (21) with the space below it, so that liquid and / or gas below the upper limit plate (21) can enter the upper part of the upper limit plate (21) through the third connecting hole (22), and liquid and / or gas above the upper limit plate (21) can enter the lower part of the upper limit plate (21) through the third connecting hole (22).

7. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 6, characterized in that: The upper limit plate (21) is a porous plate, and the third connecting holes (22) are multiple, and the multiple third connecting holes (22) are distributed at intervals on the upper limit plate (21); The upper end of the floating component (8) is also connected to an upper connecting rod (23), which is inserted into the third connecting hole (22) and can move up and down along the third connecting hole (22), and the outer peripheral cross-sectional area of ​​the upper connecting rod (23) is smaller than the cross-sectional area of ​​the third connecting hole (22).

8. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 7, characterized in that: The floating component (8) is a floating plug, comprising an upper structure (24) and a lower structure (25), the lower end of the upper structure (24) is connected to the upper end of the lower structure (25), the upper structure (24) is a cone structure, and the lower structure (25) is a columnar structure. When there are both an upper connecting rod (23) and a lower connecting rod (20), the upper end of the upper structure (24) is connected to the lower end of the upper connecting rod (23), and the outer circumferential cross-sectional area of ​​the upper end of the upper structure (24) is equal to the outer circumferential cross-sectional area of ​​the lower end of the upper connecting rod (23), and the lower end of the lower structure (25) is connected to the upper end of the lower connecting rod (20), and the outer circumferential cross-sectional area of ​​the lower end of the lower structure (25) is greater than the outer circumferential cross-sectional area of ​​the upper end of the lower connecting rod (20).

9. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 1, characterized in that: The evaporator (5) comprises an air collecting pipe (104), wherein the air collecting pipe (104) is located at the outlet end of the evaporator (5), and the other end of the balance pipe (103) is connected to the inner bottom end of the air collecting pipe (104).

10. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 1, characterized in that: It also includes a condenser (3), a liquid inlet pipe (101) and a liquid outlet pipe (102), one end of the liquid inlet pipe (101) is connected to the condenser (3), and the other end is connected to the internal top end of the outer cylinder (6) of the liquid storage tank (2), so that the refrigerant after heat exchange in the condenser (3) can be introduced into the liquid storage tank (2), and one end of the liquid outlet pipe (102) is connected to the internal bottom end of the outer cylinder (6) of the liquid storage tank (2), and the other end is connected to one end of the fluorine pump (10).

11. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 10, characterized in that: The evaporator (5) further comprises a first pipeline (201), a second pipeline (202), a third pipeline (203), a fourth pipeline (204), a fifth pipeline (205), a throttle valve (4), a one-way valve A (11), a one-way valve B (15) and an oil separator (13); the other end of the fluorine pump (10) is connected to one end of the evaporator (5) through the first pipeline (201); the throttle valve (4) is arranged on the first pipeline (201); one end of the second pipeline (202) is connected to the liquid outlet pipe (102) and the other end is connected to a position on the first pipeline (201) between the fluorine pump (10) and the throttle valve (4); and a second pipeline (202) is arranged The one-way valve A (11) only allows the fluid to flow from the liquid outlet pipe (102) to the first pipeline (201); the other end of the evaporator (5) is connected to the third pipeline (203), the third pipeline (203) is connected to the suction end of the compressor (1) through the fourth pipeline (204), the third pipeline (203) is also connected to the exhaust end of the compressor (1) through the fifth pipeline (205), the one-way valve B (15) only allows the refrigerant fluid to flow from the suction end of the compressor (1) to the exhaust end is provided on the fifth pipeline (205), and the oil separator (13) is also provided between the exhaust end of the compressor (1) and the condenser (3).

12. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 11, characterized in that: The other end of the balance pipe (103) is connected to the third pipeline (203) or to the fifth pipeline (205); alternatively, the evaporator (5) comprises an air collecting pipe (104), the air collecting pipe (104) is located at the outlet end of the evaporator (5), the other end of the balance pipe (103) is connected to the inner bottom end of the air collecting pipe (104), and the inner top end of the air collecting pipe (104) is connected to the third pipeline (203).

13. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 1, characterized in that: The oil return assembly comprises a floating body (26), a hose (27) and an oil return pipeline (206). The floating body (26) is arranged inside the outer cylinder (6), and the floating body (26) can float in the liquid in the outer cylinder (6) so as to rise or fall integrally with the liquid level height. The floating body (26) is provided with a liquid suction port so as to suck in the oil-containing mixture at the liquid surface. The upper end of the hose (27) is connected to the floating body (26) so as to rise and fall integrally with the floating body (26) so as to guide the oil-containing mixture sucked in by the floating body (26). The lower end of the hose (27) is connected to one end of the oil return pipeline (206). The oil return pipeline (206) extends out of the liquid storage tank (2) so as to guide the oil-containing mixture to the suction end of the compressor (1).

14. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 13, characterized in that: The oil return pipeline (206) is provided with a control valve (28), and the oil return pipeline (206) is provided with a heating component, and the heating component can heat the mixed liquid of refrigerant and oil in the oil return pipeline (206) to evaporate the refrigerant and separate the lubricating oil.

15. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 14, characterized in that: The heating component comprises ribs and / or fins arranged on a partial pipe section on the oil return pipeline (206), so that the partial pipe section forms a finned tube and / or a finned tube (29), and the finned tube and / or the finned tube (29) is arranged at the return air port of the evaporator (5).

16. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 15, characterized in that: The finned tube and / or finned tube (29) is arranged outside and / or inside the evaporator (5); when the finned tube and / or finned tube (29) is arranged inside the evaporator (5), the finned tube and / or finned tube (29) is integrally formed with the heat exchange tube of the evaporator (5).

17. The refrigeration system with a function of adjusting the amount of redundant refrigerant according to claim 14, characterized in that: It also includes a gas-liquid separator (30), which is arranged at the suction end of the compressor (1) and is connected to the suction end, and the other end of the oil return pipeline (206) is connected to the interior of the gas-liquid separator (30), and the control valve (28) is a solenoid valve.

18. A control method for a refrigeration system with a function of adjusting the amount of redundant refrigerant according to any one of claims 14 to 17, characterized in that: include: A detection step, detecting whether the compressor is stopped or the fluorine pump is stopped, and detecting the temperature of the liquid storage tank (2); A determination step, determining the relationship between the temperature of the liquid storage tank (2) and a preset temperature T0; A control step, when the compressor is stopped or the fluorine pump is stopped, and the temperature of the liquid storage tank (2) is less than T0 for more than t0 time, controlling the control valve (28) to open, wherein t0 is a preset time.

19. The control method according to claim 18, characterized in that: The control step controls the control valve (28) to be open for a duration of t1, and closes the control valve (28) after being open for t1, and turns on the internal fan (14) opposite to the evaporator (5) and keeps running for t2; and turns on the control valve (28) and the internal fan (14) in sequence again when the temperature condition of the liquid storage tank is met next time, wherein t1 is a first preset time and t2 is a second preset time.

Images