Liquid storage tank capable of adjusting amount of stored liquid, refrigerating system and control method

Abstract

The invention provides a liquid storage tank capable of adjusting the amount of stored liquid, a refrigerating system and a control method.The liquid storage tank comprises an inner cylinder and an outer cylinder, an outlet pipe is arranged at the bottom of the inner cylinder so that fluid in the inner cylinder can be guided out, and a valve structure is arranged between the inner cylinder and the outer cylinder; in the compression refrigeration mode, the valve structure can guide fluid in the outer cylinder into the inner cylinder when the frequency of the compressor is increased, and the amount of the fluid discharged from the outlet pipe is increased. In the compression refrigeration mode, the valve structure can guide the fluid in the inner cylinder into the outer cylinder when the compressor is subjected to frequency reduction, and the amount of the fluid discharged from the outlet pipe is reduced; in the fluorine pump refrigeration mode, the valve structure can guide fluid in the outer cylinder into the inner cylinder, and the liquid level in the inner cylinder rises. According to the invention, the problem of refrigerant redundancy caused by difference of refrigerant filling amounts required under different operation conditions of a fluorine pump compression refrigeration system can be solved, and the problems of retention and release of refrigerant liquid are solved, so that better circulation amounts required by the refrigeration system under various operation conditions can be met as much as possible.

Description

Technical Field

[0001] The invention relates to the technical field of refrigeration, and in particular to a liquid storage tank capable of adjusting the amount of stored liquid, a refrigeration system 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 under 100% load is guaranteed during the design and development of the refrigeration system, then the optimal refrigerant filling volume under 75% or 50% or other low-frequency operation conditions is relatively small. Therefore, 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 is usually relatively large in the fluorine pump mode. 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, and 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.

[0007] Since the fluorine pump compression refrigeration system in the prior art has technical problems such as refrigerant redundancy caused by the difference in the refrigerant filling amount required under different operating conditions, the present invention studies and designs a liquid storage tank, a refrigeration system and a control method with adjustable storage liquid amount. Summary of the invention

[0008] Therefore, the technical problem to be solved by the present invention is to overcome the defect of refrigerant redundancy caused by the difference in the refrigerant filling amount required under different operating conditions in the fluorine pump compression refrigeration system in the prior art, thereby providing a liquid storage tank, refrigeration system and control method with adjustable storage liquid amount.

[0009] In order to solve the above problems, the present invention provides a liquid storage tank capable of adjusting the amount of stored liquid, comprising:

[0010] An inner cylinder and an outer cylinder, wherein the inner cylinder is located inside the outer cylinder, and the outer cylinder is sleeved on the outer circumference of the inner cylinder. An outlet pipe is arranged at the bottom of the inner cylinder so as to discharge the fluid in the inner cylinder. A valve structure is arranged between the inner cylinder and the outer cylinder. In a compression refrigeration mode, the valve structure can introduce the fluid in the outer cylinder into the inner cylinder when the compressor frequency is increased, so that the amount of fluid discharged from the outlet pipe is increased; in a compression refrigeration mode, the valve structure can also introduce the fluid in the inner cylinder into the outer cylinder when the compressor frequency is reduced, so that the amount of fluid discharged from the outlet pipe is reduced; in a fluorine pump refrigeration mode, the valve structure can introduce the fluid in the outer cylinder into the inner cylinder, so that the liquid level in the inner cylinder is increased.

[0011] In some embodiments,

[0012] A pressure-taking port is provided at the top of the outer cylinder, and a pressure-taking pipe is inserted at the pressure-taking port so that the interior of the outer cylinder is connected to an external pressure gas source; in the compression refrigeration mode and when the compressor is frequency-increasing, the pressure-taking pipe can pass gas with a pressure greater than that of the inner cylinder into the interior of the outer cylinder; in the compression refrigeration mode and when the compressor is frequency-reducing, the pressure-taking pipe can draw gas from the interior of the outer cylinder and make the pressure inside the outer cylinder lower than the pressure inside the inner cylinder; in the fluorine pump refrigeration mode, the pressure-taking pipe can pass gas with a pressure greater than that of the inner cylinder into the interior of the outer cylinder.

[0013] In some embodiments,

[0014] It also includes an inlet pipe, which is inserted into the inner cylinder from above the inner cylinder so as to allow fluid to flow into the inner cylinder;

[0015] A liquid level gauge is also provided inside the outer cylinder to detect the liquid level inside the outer cylinder.

[0016] In some embodiments,

[0017] The valve structure includes a first one-way valve and a second one-way valve, wherein the first one-way valve is arranged on the cylinder wall of the inner cylinder to only allow the fluid in the outer cylinder to enter the inner cylinder through the first one-way valve; and the second one-way valve is arranged on the cylinder wall of the inner cylinder to only allow the fluid in the inner cylinder to enter the outer cylinder through the second one-way valve.

[0018] In some embodiments,

[0019] The first one-way valve and the second one-way valve have the same valve structure, and both include a valve body, a large channel and a small channel. The valve body is arranged on the cylinder wall of the inner cylinder, and the large channel and the small channel are both opened inside the valve body. The flow cross-sectional area of ​​the large channel is larger than the flow cross-sectional area of ​​the small channel, so that the fluid can only flow from the small channel to the large channel; the first one-way valve is arranged so that its small channel is connected to the cavity of the outer cylinder, and its large channel is connected to the cavity of the inner cylinder; the second one-way valve is arranged so that its small channel is connected to the cavity of the inner cylinder, and its large channel is connected to the cavity of the outer cylinder.

[0020] In some embodiments,

[0021] The valve structure also includes a valve core and an elastic structure, one end of the small channel is located at one axial end of the valve body, the other end of the small channel extends toward the inside of the valve body, one end of the large channel is communicated with the other end of the small channel, and the other end of the large channel is communicated to the other axial end of the valve body, the valve core and the elastic structure are arranged in the large channel, the valve core is relatively close to the small channel, the elastic structure is relatively far away from the small channel, and one end of the elastic structure is connected to the valve core, and the other end of the elastic structure is fixed, and an elastic thrust can be applied to the valve core. When the pressure in the small channel is greater than the pressure in the large channel plus the elastic thrust, the valve core is pushed to move in a direction away from the small channel, so that the small channel is communicated with the large channel. When the pressure in the large channel plus the elastic thrust is greater than the pressure in the small channel, the valve core is pushed to block the connection between the small channel and the large channel, so that the small channel is not communicated with the large channel.

[0022] In some embodiments,

[0023] The position where the large channel is connected to the small channel is set as a transition channel with a trapezoidal longitudinal section, the valve core includes a first valve stem and a second valve stem, the first valve stem can be inserted into the small channel and reciprocate in the small channel, one end of the first valve stem is connected to one end of the second valve stem, the cross-sectional area of ​​the second valve stem is larger than the cross-sectional area of ​​the first valve stem, and the second valve stem is set in the large channel and can also reciprocate in the large channel, and the position where the second valve stem is connected to the first valve stem is set as a transition structure with a trapezoidal longitudinal section, and the transition structure cooperates with the transition channel;

[0024] A limiting structure is provided in a partial section of the large channel away from the small channel, one end of the limiting structure is abutted or fixedly connected to one end of the elastic structure, the other end of the limiting structure can extend to the other end surface of the valve body, and the interior of the limiting structure has a hollow flow channel to form a channel for fluid circulation.

[0025] In some embodiments,

[0026] The first one-way valve and the second one-way valve are both cylindrical structures, and their central axes are both arranged in the horizontal direction. The inner cylinder and the outer cylinder are also cylindrical structures, and their central axes are both arranged in the vertical direction.

[0027] The present invention also provides a refrigeration system, which includes the aforementioned liquid storage tank, and also includes a compressor, a condenser, a throttle valve, an evaporator and a fluorine pump, the throttle valve is arranged between the condenser and the evaporator, the liquid storage tank is arranged between the condenser and the throttle valve, the outlet end of the compressor is connected to the condenser, the inlet end of the compressor is connected to the evaporator, and the fluorine pump is arranged in parallel on the pipeline between the throttle valve and the liquid storage tank.

[0028] In some embodiments,

[0029] It also includes a first bypass pipeline, a second bypass pipeline and a third bypass pipeline. One end of the first bypass pipeline is connected to the pressure-taking pipe, and the other end of the first bypass pipeline can be connected to the outlet end of the compressor or the inlet end of the condenser through the second bypass pipeline. The other end of the first bypass pipeline can also be connected to the inlet end of the compressor or the outlet end of the evaporator through the third bypass pipeline, so that when the compressor increases the frequency, gas with a pressure greater than the internal pressure of the inner cylinder can be introduced into the outer cylinder through the second bypass pipeline, the first bypass pipeline and the pressure-taking pipe, and when the compressor decreases the frequency, the gas in the outer cylinder can be sucked through the third bypass pipeline, the first bypass pipeline and the pressure-taking pipe to reduce the pressure inside the outer cylinder to less than the pressure inside the inner cylinder; and gas with a pressure greater than the internal pressure of the inner cylinder can be introduced into the outer cylinder through the third bypass pipeline, the first bypass pipeline and the pressure-taking pipe in the fluorine pump operation mode.

[0030] In some embodiments,

[0031] When the compressor increases its frequency, one end of the second bypass pipe is connected to the outlet of the compressor to introduce gas from the outlet of the compressor; when the compressor decreases its frequency, one end of the third bypass pipe is connected to the inlet of the compressor to draw out at least part of the gas in the outer cylinder to the inlet of the compressor; in the fluorine pump operation mode, one end of the third bypass pipe is connected to the outlet of the evaporator to introduce gas from the outlet of the evaporator.

[0032] In some embodiments,

[0033] It also includes a control valve and a three-way valve, wherein the control valve is arranged on the first bypass pipeline, the three-way valve is arranged at a position where the first bypass pipeline, the second bypass pipeline and the third bypass pipeline are connected together, and the three-way valve includes an O end, an N end and an M end, the O end is connected to the other end of the first bypass pipeline, the N end is connected to one end of the second bypass pipeline, and the M end is connected to one end of the third bypass pipeline, and the three-way valve can be switched between a first state and a second state, the first state is that the O end is connected to the N end and the M end is disconnected, and the second state is that the O end is connected to the M end and the N end is disconnected;

[0034] When the compressor increases the frequency, the control valve is controlled to be opened, and at the same time, the three-way valve is controlled so that the O terminal is connected to the N terminal, and the M terminal is disconnected; when the compressor decreases the frequency, the control valve is controlled to be opened, and at the same time, the three-way valve is controlled so that the O terminal is connected to the M terminal, and the N terminal is disconnected; in the fluorine pump operation mode, the control valve is controlled to be opened, and at the same time, the three-way valve is controlled so that the O terminal is connected to the M terminal, and the N terminal is disconnected.

[0035] In some embodiments,

[0036] A first throttling element is also provided on the second bypass pipeline, and a second throttling element is also provided on the third bypass pipeline.

[0037] In some embodiments,

[0038] The first throttling element is a capillary, and the second throttling element is a capillary; the control valve is a solenoid valve, which opens when the solenoid valve is powered on and closes when the solenoid valve is powered off; when the three-way valve is powered on, the O end is connected to the N end, and the M end is disconnected; when the three-way valve is powered off, the O end is connected to the M end, and the N end is disconnected.

[0039] In some embodiments,

[0040] It also includes a first branch and a second branch. The first branch is arranged in parallel at both ends of the compressor. A one-way valve B is arranged on the first branch to only allow the fluid to flow from the evaporator to the condenser. The branch where the fluorine pump is located is the second branch. A one-way valve A is arranged on the pipeline parallel to the second branch to only allow the fluid to flow from the liquid storage tank to the throttle valve.

[0041] The present invention also provides a control method for the refrigeration system as described above, comprising:

[0042] A judgment step is to detect whether the refrigeration system is operating in a compression refrigeration mode or a fluorine pump refrigeration mode;

[0043] A detection step, when operating in a compression cooling mode, detecting whether the compressor is increasing or decreasing in frequency;

[0044] The control step is as follows: when the refrigeration system is operating in the compression refrigeration mode and the compressor is increasing in frequency, the control valve is controlled to be opened, and the three-way valve is controlled to connect the O terminal with the N terminal and disconnect the M terminal; when the compressor is decreasing in frequency, the control valve is controlled to be opened, and the three-way valve is controlled to connect the O terminal with the M terminal and disconnect the N terminal; when the refrigeration system is operating in the compression fluorine pump operation mode, the control valve is controlled to be opened, and the three-way valve is controlled to connect the O terminal with the M terminal and disconnect the N terminal.

[0045] In some embodiments,

[0046] When the liquid storage tank is also provided with a liquid level meter:

[0047] The detection step also detects the height of the liquid level inside the outer cylinder by means of the liquid level gauge;

[0048] The control step, when the refrigeration system operates in the compression refrigeration mode, and the compressor is frequency-up and the control steps of the control valve and the three-way valve are executed, if the liquid level detected by the liquid level meter drops to a first preset height, the control valve is first controlled to close, and then the three-way valve is controlled to be powered off, so that the O terminal is connected to the M terminal, and the N terminal is disconnected;

[0049] When the refrigeration system operates in compression refrigeration mode, and the compressor is frequency-reduced and the control steps of the control valve and the three-way valve are executed, if the liquid level detected by the liquid level meter rises to a second preset height, the control valve is controlled to close and the three-way valve is maintained in a power-off state;

[0050] When the refrigeration system operates in the fluorine pump refrigeration mode, if the liquid level detected by the liquid level meter drops to a third preset height, the control valve is controlled to close, and the three-way valve is maintained in an off-power state.

[0051] The present invention provides a liquid storage tank, a refrigeration system and a control method capable of adjusting the amount of stored liquid, which have the following beneficial effects:

[0052] 1. The present invention can achieve a specific fluid flow relationship between the inner and outer cylinders by configuring the liquid storage tank to have an inner and outer cylinder sleeve structure, and a valve structure is provided between the inner and outer cylinders. The outlet pipe at the bottom of the inner cylinder can guide the fluid out, and the specific fluid flow relationship between the inner and outer cylinders is as follows: in the compression refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder when the compressor frequency is increased, so that the amount of fluid discharged from the outlet pipe increases; in the compression refrigeration mode, the valve structure can also guide the fluid in the inner cylinder into the outer cylinder when the compressor frequency is reduced, so that the amount of fluid discharged from the outlet pipe decreases; in the fluorine pump refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder, so that the liquid level in the inner cylinder increases. Such a unique structure and setting form can increase the fluid flow discharged from the liquid storage tank in the compression refrigeration mode and when the frequency is increased, thereby increasing the amount of fluid entering the system for circulation. The running refrigerant flow meets the heat exchange demand of refrigeration when the high-frequency compressor is running, ensuring normal heat exchange performance. When the compressor is reduced in frequency, the fluid in the inner cylinder flows into the inner cylinder, thereby reducing the fluid flow discharged from the liquid storage tank, thereby reducing the refrigerant flow entering the system for circulation, meeting the heat exchange demand of refrigeration when the low-frequency compressor is running, avoiding excessive refrigerant entering the circulation to cause refrigerant retention, affecting the heat exchange effect, and increasing the flow resistance; and in the fluorine pump mode, the fluid in the outer cylinder can also be introduced into the inner cylinder, so that the liquid level in the inner cylinder is increased, the fluorine pump suction height in the fluorine pump mode is increased, and cavitation is avoided; it effectively solves the refrigerant redundancy problem caused by the difference in the refrigerant filling amount required under different operating conditions of the fluorine pump compression refrigeration system, and solves the problem of refrigerant liquid retention and release, so as to try to meet the optimal circulation volume required by the refrigeration system under various operating conditions.

[0053] 2. The present invention can also connect the inside of the outer cylinder with the external pressure gas source under different operating modes and operating conditions through the arrangement of the pressure port and the pressure taking tube, thereby effectively meeting the compressor mode and raising the liquid level of the inner cylinder when the frequency is increased, discharging more refrigerant into the system for circulation, and lowering the liquid level of the inner cylinder when the frequency is reduced in the compressor mode, reducing the amount of refrigerant discharged into the system for circulation, and increasing the liquid suction height of the fluorine pump in the fluorine pump mode to avoid cavitation, thereby achieving the purpose of effective and intelligent control according to the needs of different working conditions, and being able to accurately control the stored liquid, thereby ensuring that the circulation volume of the refrigeration system is within an optimal range, and avoiding too much or too little refrigerant participating in the circulation in the refrigeration system.

[0054] 3. The present invention also provides a plurality of bypass pipelines and control valves and three-way valve structures, as well as the connection relationship between the pipelines, so that the inside of the outer cylinder can be connected to the external pressure gas source under different operating modes and operating conditions, thereby effectively meeting the compressor mode and increasing the frequency to increase the liquid level of the inner cylinder, discharge more refrigerant into the system for circulation, and reducing the liquid level of the inner cylinder in the compressor mode and decreasing the frequency to reduce the amount of refrigerant discharged into the system for circulation, and increasing the suction height of the fluorine pump in the fluorine pump mode to avoid cavitation, thereby achieving the purpose of effective and intelligent control according to the needs of different working conditions, and can accurately control the stored liquid, thereby ensuring that the circulation volume of the refrigeration system is in a better range, avoiding too much or too little refrigerant participating in the circulation in the refrigeration system. The storage state of the liquid refrigerant in the liquid storage tank can be changed according to the frequency change of the compressor; in the fluorine pump compression refrigeration double-circulation system, in the fluorine pump mode, the refrigerant gas at the outlet of the evaporator can be used to migrate the refrigerant liquid in the outer cylinder of the liquid storage tank to the inner cylinder, so that the height of the refrigerant liquid in the inner cylinder of the liquid storage tank meets the requirements of the suction height of the fluorine pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is an internal cross-sectional view of the liquid storage tank capable of adjusting the amount of stored liquid of the present invention when the outer cylinder is under low pressure;

[0056] Figure 2 It is an internal cross-sectional view of the liquid storage tank capable of adjusting the amount of stored liquid of the present invention when the outer cylinder is under high pressure;

[0057] Figure 3 is an internal cross-sectional view of the one-way valve structure of the present invention;

[0058] Figure 4 It is a system diagram of a fluorine pump compression refrigeration system of the present invention having a liquid storage tank with an adjustable storage amount of liquid.

[0059] The reference numerals are:

[0060] 1. Inner tube; 2. Outer tube; 3. Outlet pipe; 4. Valve structure; 41. First one-way valve; 42. Second one-way valve; 43. Valve body; 44. Large channel; 45. Small channel; 46. Valve core; 47. Elastic structure; 48. First valve stem; 49. Second valve stem; 410. Limiting structure; 411. Hollow flow channel; 5. Pressure taking pipe; 6. Liquid level gauge; 7. Inlet pipe; 8. Compressor; 9. Condenser; 10. Throttle valve; 11. Evaporator; 12. Fluorine pump; 13. Liquid storage tank; 14. One-way valve A; 15. One-way valve B; 16. Control valve; 17. Three-way valve; O, O end; N, N end; M, M end; 18. First throttling device; 19. Second throttling device; 20. Internal fan; 21. External fan;

[0061] 101, first bypass pipeline; 102, second bypass pipeline; 103, third bypass pipeline; 201, first branch; 202, second branch. DETAILED DESCRIPTION

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] like Figure 1-4 As shown, the present invention provides a liquid storage tank capable of adjusting the amount of stored liquid, comprising:

[0069] An inner cylinder 1 and an outer cylinder 2, wherein the inner cylinder 1 is located inside the outer cylinder 2, and the outer cylinder 2 is sleeved on the outer circumference of the inner cylinder 1. An outlet pipe 3 is arranged at the bottom of the inner cylinder 1 to discharge the fluid in the inner cylinder 1, and a valve structure 4 is arranged between the inner cylinder 1 and the outer cylinder 2. In the compression refrigeration mode, the valve structure 4 can introduce the fluid in the outer cylinder 2 into the inner cylinder 1 when the compressor is frequency-increasing, so that the amount of fluid discharged from the outlet pipe 3 increases; in the compression refrigeration mode, the valve structure 4 can also introduce the fluid in the inner cylinder 1 into the outer cylinder 2 when the compressor is frequency-reducing, so that the amount of fluid discharged from the outlet pipe 3 decreases; in the fluorine pump refrigeration mode, the valve structure 4 can introduce the fluid in the outer cylinder 2 into the inner cylinder 1, so that the liquid level in the inner cylinder 1 increases.

[0070] The present invention realizes a specific fluid flow relationship between the inner and outer cylinders by configuring the liquid storage tank to have an inner and outer cylinder sleeve structure, and a valve structure is provided between the inner and outer cylinders. The outlet pipe at the bottom of the inner cylinder can guide the fluid out, and the specific fluid flow relationship between the inner and outer cylinders is as follows: in the compression refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder when the compressor frequency is increased, so that the amount of fluid discharged from the outlet pipe is increased; in the compression refrigeration mode, the valve structure can also guide the fluid in the inner cylinder into the outer cylinder when the compressor frequency is reduced, so that the amount of fluid discharged from the outlet pipe is reduced; in the fluorine pump refrigeration mode, the valve structure can guide the fluid in the outer cylinder into the inner cylinder, so that the liquid level in the inner cylinder is increased. Such a unique structure and setting form can increase the fluid flow discharged from the liquid storage tank in the compression refrigeration mode and when the frequency is increased, thereby increasing the fluid entering the system for circulation. The refrigerant flow rate is controlled to meet the heat exchange demand of refrigeration when the high-frequency compressor is running, and the normal heat exchange performance is guaranteed. When the compressor is frequency-reduced, the fluid in the inner cylinder flows into the inner cylinder, thereby reducing the fluid flow discharged from the liquid storage tank, thereby reducing the refrigerant flow entering the system for circulation, meeting the heat exchange demand of refrigeration when the low-frequency compressor is running, avoiding the situation where too much refrigerant enters the circulation and causes refrigerant retention, affecting the heat exchange effect, and increasing the flow resistance; and in the fluorine pump mode, the fluid in the outer cylinder can also be introduced into the inner cylinder, so that the liquid level in the inner cylinder is increased, the fluorine pump suction height in the fluorine pump mode is increased, and cavitation is avoided; it effectively solves the refrigerant redundancy problem caused by the difference in the refrigerant filling amount required under different operating conditions of the fluorine pump compression refrigeration system, and solves the problem of refrigerant liquid retention and release, so as to try to meet the optimal circulation amount required by the refrigeration system under various operating conditions.

[0071] In some embodiments,

[0072] A pressure-taking port is provided at the top of the outer cylinder 2, and a pressure-taking pipe 5 is inserted at the pressure-taking port so that the interior of the outer cylinder 2 is connected to an external pressure gas source; in the compression refrigeration mode and when the compressor is frequency-increasing, the pressure-taking pipe 5 can pass gas with a pressure greater than that of the inner cylinder 1 into the interior of the outer cylinder 2; in the compression refrigeration mode and when the compressor is frequency-reducing, the pressure-taking pipe 5 can draw the gas inside the outer cylinder 2 and make the pressure inside the outer cylinder 2 lower than the pressure inside the inner cylinder 1; in the fluorine pump refrigeration mode, the pressure-taking pipe 5 can pass gas with a pressure greater than that of the inner cylinder 1 into the interior of the outer cylinder 2.

[0073] The present invention can also connect the different pressure gas sources inside the outer cylinder with the outside under different operating modes and operating conditions through the arrangement of the pressure port and the pressure taking tube, thereby effectively meeting the compressor mode and raising the liquid level in the inner cylinder when the frequency is increased, discharging more refrigerant into the system for circulation, while lowering the liquid level in the inner cylinder when the frequency is reduced in the compressor mode, reducing the amount of refrigerant discharged into the system for circulation, and increasing the liquid suction height of the fluorine pump in the fluorine pump mode to avoid cavitation, thereby achieving the purpose of effective and intelligent control according to the needs of different working conditions, and being able to accurately control the stored liquid, thereby ensuring that the circulation volume of the refrigeration system is within an optimal range, avoiding too much or too little refrigerant participating in the circulation in the refrigeration system.

[0074] In some embodiments,

[0075] It also includes an inlet pipe 7, which is inserted into the inner tube 1 from above the inner tube 1 so as to allow fluid to flow into the inner tube 1;

[0076] A liquid level gauge 6 is also provided inside the outer cylinder 2 to detect the liquid level inside the outer cylinder 2 .

[0077] The present invention can also normally connect the refrigerant at the outlet end of the condenser through the inlet pipe to enter therein, and the liquid level gauge arranged inside the outer cylinder can effectively detect the liquid level height inside the outer cylinder, so as to judge whether the liquid level in the outer cylinder is too low during the process of introducing the fluid in the outer cylinder into the inner cylinder, and judge whether the liquid level in the outer cylinder is too high during the process of introducing the fluid in the inner cylinder into the outer cylinder, thereby effectively avoiding the occurrence of these situations and preventing the liquid from reaching the top.

[0078] The present invention provides a novel liquid storage tank, which is preferably a coaxially arranged inner and outer double tank structure, and has two built-in one-way valves connecting the inner cylinder and the outer cylinder space. The outer cylinder of the liquid storage tank is also provided with a liquid level gauge (such as a float liquid level gauge, a liquid level sensor, etc.); the inner cylinder is a conventional liquid storage tank structure design, with an inlet and an outlet, and the top of the outer cylinder is provided with a pressure port; by changing the pressure of the pressure port, the one-way valves are respectively opened to change the liquid flow direction between the outer cylinder and the inner cylinder, thereby adjusting the liquid storage state in the liquid storage tank; the flow direction of the two one-way valves, one only allows the fluid to flow from the outer cylinder to the inner cylinder ( Figure 1 The one-way valve on the left side of the middle), and the other one only allows fluid to flow from the inner cylinder to the outer cylinder ( Figure 1 middle right non-return valve).

[0079] The refrigeration system of the present invention using the above-mentioned new liquid storage tank can change the storage state of the liquid refrigerant in the liquid storage tank according to the frequency change of the compressor; in the fluorine pump compression refrigeration double-circulation system, the refrigerant gas at the outlet of the evaporator can be used in the fluorine pump mode to transfer the refrigerant liquid in the outer cylinder of the liquid storage tank to the inner cylinder, so that the height of the refrigerant liquid in the inner cylinder of the liquid storage tank can adapt to the liquid suction height requirement of the fluorine pump.

[0080] In some embodiments,

[0081] The valve structure 4 includes a first one-way valve 41 and a second one-way valve 42. The first one-way valve 41 is arranged on the cylinder wall of the inner cylinder 1 to only allow the fluid in the outer cylinder 2 to enter the inner cylinder 1 through the first one-way valve 41; the second one-way valve 42 is arranged on the cylinder wall of the inner cylinder 1 to only allow the fluid in the inner cylinder 1 to enter the outer cylinder 2 through the second one-way valve 42.

[0082] This is the preferred structural form of the valve structure of the present invention, that is, by setting a structure with two one-way valves, the first one-way valve only allows the fluid in the outer cylinder to flow into the inner cylinder, and the second one-way valve only allows the fluid in the inner cylinder to flow into the outer cylinder, so that when the compressor is in frequency-up or fluorine pump mode, higher-pressure gas is introduced through the pressure-taking pipe, driving the fluid inside the outer cylinder to flow into the inner cylinder through the first one-way valve, increasing the liquid level of the inner cylinder or discharging more refrigerant into the system for circulation, and when the compressor is frequency-down, at least part of the gas inside the outer cylinder is drawn out through the pressure-taking pipe to reduce the pressure inside the outer cylinder, driving the fluid in the inner cylinder to flow into the outer cylinder through the second one-way valve, discharging a smaller amount of refrigerant into the system for circulation, so as to avoid the occurrence of refrigerant retention in the heat exchanger, improve the heat exchange performance, and solve the problem of refrigerant redundancy.

[0083] In some embodiments,

[0084] The first one-way valve 41 and the second one-way valve 42 have the same valve structure, and both include a valve body 43, a large channel 44 and a small channel 45. The valve body 43 is arranged on the cylinder wall of the inner cylinder 1, and the large channel 44 and the small channel 45 are both opened inside the valve body 43. The flow cross-sectional area of ​​the large channel 44 is larger than the flow cross-sectional area of ​​the small channel 45, so that the fluid can only flow from the small channel 45 to the large channel 44; the first one-way valve 41 is configured so that its small channel 45 is connected to the cavity of the outer cylinder 2, and its large channel 44 is connected to the cavity of the inner cylinder 1; the second one-way valve 42 is configured so that its small channel 45 is connected to the cavity of the inner cylinder 1, and its large channel 44 is connected to the cavity of the outer cylinder 2.

[0085] This is the specific structural form of the two one-way valves of the present invention. The two one-way valves have the same structure and both include a large channel and a small channel structure to achieve the function and effect of only allowing flow from the small channel to the large channel. The small channel end of the one-way valve is usually defined as the inlet, and the large channel end is defined as the outlet. The flow direction of the one-way valve is along Figure 3 The direction is from top to bottom, as shown by the flow direction mark located at the hollow outer bolt, in the specific embodiment of the present invention, the one-way valve is preferably arranged in a horizontal direction, that is, the flow direction is horizontally from left to right or from right to left.

[0086] In some embodiments,

[0087] The valve structure further includes a valve core 46 and an elastic structure 47. One end of the small channel 45 is located at one axial end of the valve body 43, and the other end of the small channel 45 extends toward the inside of the valve body 43. One end of the large channel 44 is communicated with the other end of the small channel 45, and the other end of the large channel 44 is communicated with the other axial end of the valve body 43. The valve core 46 and the elastic structure 47 are arranged in the large channel 44. The valve core 46 is relatively close to the small channel 45, and the elastic structure 47 is relatively far away from the small channel 45. One end of the elastic structure 47 is connected to the large channel 44. The valve core 46 is connected, and the other end of the elastic structure 47 is fixed, which can apply an elastic thrust to the valve core 46. When the pressure in the small channel 45 is greater than the pressure in the large channel 44 plus the elastic thrust, the valve core 46 is pushed to move away from the small channel 45, so that the small channel 45 is connected to the large channel 44. When the pressure in the large channel 44 plus the elastic thrust is greater than the pressure in the small channel 45, the valve core 46 is pushed to block the connection between the small channel 45 and the large channel 44, so that the small channel 45 is not connected to the large channel 44.

[0088] This is a further preferred structural form of the valve structure of the present invention. The structure of the valve core can move according to the pressure at both ends, thereby opening or closing the connection between the small channel and the large channel. The elastic structure provides a restoring force for the valve core, so that it returns to a position combined with the connection position of the small and large channels, thereby closing the connection of the channels.

[0089] When the fluid pressure P1 inside the small channel is greater than the fluid pressure P2 inside the large channel + the spring force F (ignore the gravity, friction force, etc. of the valve core, for example, gravity can be ignored when the one-way valve is placed horizontally), the one-way valve is opened, the conical end of the valve core is pushed away from the conical transition section, and the fluid flows through the conical gap; the lengths of the hollow outer bolt rotating into the large channel are different, that is, the initial compression amount of the spring is different, thereby achieving different spring forces. The greater the spring force, the greater the pressure difference P1-P2 of the fluid required to open the one-way valve.

[0090] In some embodiments,

[0091] The position where the large channel 44 is connected to the small channel 45 is set as a transition channel with a trapezoidal longitudinal section. The valve core 46 includes a first valve stem 48 and a second valve stem 49. The first valve stem 48 can be inserted into the small channel 45 and reciprocate in the small channel 45. One end of the first valve stem 48 is connected to one end of the second valve stem 49. The cross-sectional area of ​​the second valve stem 49 is larger than that of the first valve stem 48. The second valve stem 49 is set in the large channel 44 and can also reciprocate in the large channel 44. The position where the second valve stem 49 is connected to the first valve stem 48 is set as a transition structure with a trapezoidal longitudinal section. The transition structure cooperates with the transition channel.

[0092] A limiting structure 410 is provided in a portion of the large channel 44 away from the small channel 45, one end of the limiting structure 410 is abutted or fixed to one end of the elastic structure 47, the other end of the limiting structure 410 can extend to the other end face of the valve body 43, and the interior of the limiting structure 410 has a hollow flow channel 411 to form a channel for fluid circulation.

[0093] This is a further preferred structural form of the valve structure of the present invention, that is, the valve core preferably includes a first and a second part with different cross-sectional areas, which cooperate with the small channel and the large channel respectively, and the matching structure of the trapezoidal structure can facilitate guiding the valve core and is more conducive to closing the channel. The setting of the limiting structure can provide support for the elastic structure, and it is preferably threadedly connected to the inner wall of the large channel to facilitate the installation and disassembly of internal structures such as the valve core and the elastic structure.

[0094] like Figure 3 As shown, the one-way valve of the present invention is composed of a valve body 43, a valve core 46, a spring (elastic structure 47) and a hollow outer bolt (limiting structure 410), and the valve body has a small channel 45 and a large channel 44 inside, and a conical transition section is provided between the small channel 45 and the large channel 44, and an internal thread is provided on the inner wall surface of the large channel of the valve body;

[0095] The valve core has a conical end with the same inclination angle, which can be tightly combined with the conical transition section, and when the conical end of the valve core fits the conical transition section, the valve core can completely block the small channel (the diameter of the valve core body is larger than the diameter of the small channel), thereby achieving the closing effect of the one-way valve;

[0096] Furthermore, a slender positioning rod is connected to the conical end of the valve core, and the diameter of the positioning rod is smaller than the diameter of the small channel. The function of the positioning rod is to ensure that the valve core is located near the central axis of the one-way valve as much as possible and to prevent the valve core from deflecting.

[0097] The other end surface of the valve core is connected to a spring, and the two are arranged together inside the large channel of the valve body, and the valve core is arranged between the conical transition section of the valve body and the spring;

[0098] The hollow outer bolt has an outer thread feature, and is used in conjunction with the inner thread of the large channel to form the same specification. The inner hollow channel of the hollow outer bolt can be a cylindrical hole of an inner hexagonal type, a cylindrical hole of a square type, or a cylindrical hole of other types. One of its functions is to achieve circulation, and the second function is to screw the hollow outer bolt into the large channel with the help of a tool (the outer end face of the hollow outer bolt may be inside the large channel or outside the large channel); after the hollow outer bolt is connected and positioned with the valve body by using a thread pair, the inner end face of the hollow outer bolt abuts against the spring, and the conical end of the valve core is fitted on the conical surface of the conical transition section, and the spring is in a compressed state, thereby ensuring the conical fitting strength between the valve core and the valve body, and ensuring the closed state of the one-way valve;

[0099] Alternatively, the interior of the hollow outer bolt is a cylindrical through hole, and the sum of the length of the hollow outer bolt and the length of the valve core is greater than the length of the large channel, thereby ensuring that the hollow outer bolt has sufficient length, so that after the hollow outer bolt is screwed into the valve body, it still has sufficient length without entering the valve body, thereby realizing the rotation of the hollow outer bolt manually or using other tools.

[0100] In some embodiments,

[0101] The first one-way valve 41 and the second one-way valve 42 are both cylindrical structures, and their central axes are arranged in the horizontal direction. The inner tube 1 and the outer tube 2 are also cylindrical structures, and their central axes are arranged in the vertical direction.

[0102] This is the preferred structural form of the first and second one-way valves of the present invention. Both are cylindrical structures and are arranged in the horizontal direction. The influence of gravity at both ends of the valve core can be almost ignored, making the response and control more precise. The central axis of the liquid storage tank is preferably arranged in the vertical direction.

[0103] like Figure 1 and Figure 2 As shown, the adjustable liquid storage tank provided by the present invention is composed of a sealed inner cylinder, a sealed outer cylinder, a pressure-taking pipe, a liquid inlet pipe and a liquid outlet pipe. The inner cylinder and the outer cylinder are coaxially arranged, and the upper and lower ends of the inner cylinder are respectively abutted against the inner top end and the inner bottom surface of the outer cylinder, and the connection is welded and sealed;

[0104] The liquid inlet pipe and the liquid outlet pipe are arranged on the inner cylinder, and the pressure taking pipe is arranged on the top end of the outer cylinder;

[0105] Two communication holes are arranged on the wall surface of the inner cylinder close to the bottom;

[0106] Each of the communicating holes is provided with a one-way valve, wherein the flow direction of one of the one-way valves is from the outer cylinder to the inner cylinder (left one-way valve), and the flow direction of the other one-way valve is from the inner cylinder to the outer cylinder (right one-way valve);

[0107] The valve body of the one-way valve and the communicating hole are welded and sealed and fixed;

[0108] Furthermore, a liquid level gauge (including but not limited to a float level gauge, a liquid level sensor, etc.) is also provided on the outer cylinder of the liquid storage tank;

[0109] Furthermore, the pressure-taking tube and the liquid level gauge are respectively located near the two ends of a diameter direction of the liquid storage tank, and the distance between the two is as far as possible to prevent the pressure-taking tube from causing excessive disturbance to the liquid level in the outer cylinder space due to the fluid entering and leaving the pressure-taking tube, thereby avoiding excessive influence on the measurement of the liquid level gauge;

[0110] Furthermore, after the pressure-taking pipe enters the outer cylinder, the pipe opening is as close as possible to the inner top of the outer cylinder to prevent the fluid in and out of the pressure-taking pipe from causing excessive disturbance to the liquid surface in the outer cylinder; the pipe opening of the liquid outlet pipe located in the inner cylinder space is as close as possible to the inner bottom surface of the inner cylinder to ensure normal liquid outflow (if the pipe opening inside the liquid outlet pipe is too high, it is easy to absorb the gas at the top and cause liquid interruption);

[0111] Furthermore, the outer cylinder is composed of an upper cylinder and a lower cylinder, which are welded and sealed; the top and / or bottom of the inner cylinder pass through the top and bottom of the outer cylinder respectively, and the connection is welded and sealed; such a structural design is conducive to the smooth implementation of the production process.

[0112] The present invention also provides a refrigeration system, which includes the aforementioned liquid storage tank 13, and also includes a compressor 8, a condenser 9, a throttle valve 10, an evaporator 11 and a fluorine pump 12, wherein the throttle valve 10 is arranged between the condenser 9 and the evaporator 11, the liquid storage tank 13 is arranged between the condenser 9 and the throttle valve 10, the outlet end of the compressor 8 is connected to the condenser 9, the inlet end of the compressor 8 is connected to the evaporator 11, and the fluorine pump 12 is arranged in parallel on the pipeline between the throttle valve 10 and the liquid storage tank 13.

[0113] The unique refrigeration system of the present invention can, in the compression refrigeration mode, allow the valve structure to introduce the fluid in the outer cylinder into the inner cylinder when the compressor frequency is increased, so that the amount of fluid discharged from the outlet pipe is increased; in the compression refrigeration mode, the valve structure can also introduce the fluid in the inner cylinder into the outer cylinder when the compressor frequency is reduced, so that the amount of fluid discharged from the outlet pipe is reduced; in the fluorine pump refrigeration mode, the valve structure can introduce the fluid in the outer cylinder into the inner cylinder, so that the liquid level in the inner cylinder is increased. Such a unique structure and setting form can increase the fluid flow discharged from the liquid storage tank in the compression refrigeration mode and frequency increase, thereby increasing the refrigerant flow entering the system for circulation, meeting the heat exchange requirements for refrigeration when the high-frequency compressor is running, and ensuring normal heat exchange performance. When the compressor frequency is reduced, the fluid in the inner cylinder flows into the inner cylinder, thereby reducing the fluid flow discharged from the liquid storage tank, thereby reducing the refrigerant flow entering the system for circulation, meeting the refrigeration heat exchange requirements when the low-frequency compressor is running, avoiding excessive refrigerant entering the circulation and causing refrigerant retention, affecting the heat exchange effect, and increasing the flow resistance; and in the fluorine pump mode, the fluid in the outer cylinder can also be introduced into the inner cylinder, so that the liquid level in the inner cylinder increases, increasing the fluorine pump suction height in the fluorine pump mode, and avoiding cavitation; effectively solving the refrigerant redundancy problem caused by the difference in refrigerant filling amount required under different operating conditions of the fluorine pump compression refrigeration system, and solving the problem of refrigerant liquid retention and release, so as to try to meet the optimal circulation volume required by the refrigeration system under various operating conditions.

[0114] The present invention designs a novel liquid storage tank, which is preferably a coaxially arranged inner and outer double tank structure, and has two built-in one-way valves connecting the inner cylinder and the outer cylinder space. A liquid level gauge (such as a float level gauge, a liquid level sensor, etc.) is also arranged on the outer cylinder of the liquid storage tank; the inner cylinder is a conventional liquid storage tank structure, with an inlet and an outlet, and a pressure port is provided on the top of the outer cylinder; by changing the pressure at the pressure port, the one-way valves are respectively opened to change the liquid flow direction between the outer cylinder and the inner cylinder, thereby adjusting the liquid storage state in the liquid storage tank.

[0115] Can solve the following problems:

[0116] The refrigerant redundancy problem caused by the difference in the refrigerant filling amount required under different operating conditions of the fluorine pump compression refrigeration system is solved, and the problem of refrigerant liquid retention and release is solved to try to meet the optimal circulation volume required by the refrigeration system under various operating conditions.

[0117] In some embodiments,

[0118] The evaporator 11 also includes a first bypass line 101, a second bypass line 102, and a third bypass line 103. One end of the first bypass line 101 is connected to the pressure-taking line 5, and the other end of the first bypass line 101 can be connected to the outlet end of the compressor 8 or to the inlet end of the condenser 9 through the second bypass line 102. The other end of the first bypass line 101 can also be connected to the inlet end of the compressor 8 or to the outlet end of the evaporator 11 through the third bypass line 103, so that the compressor 8 can be connected to the outlet end of the evaporator 11 through the second bypass line when the compressor 8 is upgraded. 102, the first bypass pipeline 101 and the pressure-taking pipe 5 are used to introduce gas with a pressure greater than the internal pressure of the inner cylinder 1 into the outer cylinder 2, and when the compressor 8 is reduced in frequency, the gas inside the outer cylinder 2 can be sucked through the third bypass pipeline 103, the first bypass pipeline 101 and the pressure-taking pipe 5 to reduce the pressure inside the outer cylinder 2 to be lower than the pressure inside the inner cylinder 1; and the gas with a pressure greater than the internal pressure of the inner cylinder 1 can be introduced into the outer cylinder 2 through the third bypass pipeline 103, the first bypass pipeline 101 and the pressure-taking pipe 5 in the fluorine pump operation mode.

[0119] The present invention can pass gases of different pressures into the pressure-taking pipe of the outer cylinder through the arrangement of the first, second and third bypass pipelines, thereby realizing the compressor mode and raising the liquid level of the inner cylinder when the frequency is increased, discharging more refrigerant into the system for circulation, while lowering the liquid level of the inner cylinder when the frequency is reduced in the compressor mode, reducing the amount of refrigerant discharged into the system for circulation, and increasing the liquid suction height of the fluorine pump in the fluorine pump mode to avoid cavitation, thereby achieving the purpose of effective and intelligent control according to the requirements of different working conditions, and being able to accurately control the stored liquid, thereby ensuring that the circulation volume of the refrigeration system is within an optimal range, and avoiding too much or too little refrigerant participating in the circulation in the refrigeration system.

[0120] In some embodiments,

[0121] When the compressor 8 increases its frequency, one end of the second bypass pipe 102 is connected to the outlet end of the compressor 8 to introduce gas from the outlet end of the compressor 8; when the compressor 8 decreases its frequency, one end of the third bypass pipe 103 is connected to the inlet end of the compressor 8 to draw out at least part of the gas inside the outer tube 2 to the inlet end of the compressor 8; in the fluorine pump operation mode, one end of the third bypass pipe 103 is connected to the outlet end of the evaporator 11 to introduce gas from the outlet end of the evaporator 11.

[0122] This is a further preferred connection position of the second and third bypass lines of the present invention, namely, when the compressor is frequency-increasing, it is connected to the outlet end of the compressor, and the high-pressure gas at the outlet end of the compressor can drive the liquid in the outer cylinder into the inner cylinder, thereby increasing the amount of refrigerant circulating in the system; while when the compressor is frequency-reducing, it is connected to the inlet end of the compressor, and the gas inside the outer cylinder can be sucked by the low-pressure at the inlet end of the compressor to reduce the pressure inside the outer cylinder and drive the liquid in the inner cylinder into the outer cylinder, thereby reducing the amount of refrigerant circulating in the system and reducing redundancy; in the fluorine pump mode, the discharge height in the inner cylinder can be effectively increased to prevent cavitation.

[0123] In some embodiments,

[0124] It also includes a control valve 16 and a three-way valve 17, wherein the control valve 16 is arranged on the first bypass pipeline 101, and the three-way valve 17 is arranged at a position where the first bypass pipeline 101, the second bypass pipeline 102 and the third bypass pipeline 103 are connected together, and the three-way valve 17 includes an O end O, an N end N and an M end M, wherein the O end O is connected to the other end of the first bypass pipeline 101, the N end N is connected to one end of the second bypass pipeline 102, and the M end M is connected to one end of the third bypass pipeline 103, and the three-way valve 17 can switch between a first state and a second state, wherein the first state is that the O end O is connected to the N end N and the M end M is disconnected, and the second state is that the O end O is connected to the M end M and the N end N is disconnected;

[0125] When the compressor 8 increases its frequency, the control valve 16 is controlled to be opened, and at the same time, the three-way valve 17 is controlled so that the O end O is connected to the N end N, and the M end M is disconnected; when the compressor 8 decreases its frequency, the control valve 16 is controlled to be opened, and at the same time, the three-way valve 17 is controlled so that the O end O is connected to the M end M, and the N end N is disconnected; in the fluorine pump operation mode, the control valve 16 is controlled to be opened, and at the same time, the three-way valve 17 is controlled so that the O end O is connected to the M end M, and the N end N is disconnected.

[0126] The present invention also provides a plurality of bypass pipelines and control valves and three-way valve structures, as well as the connection relationship between the pipelines, so that the inside of the outer cylinder can be connected to the external pressure gas source under different operating modes and operating conditions, thereby effectively meeting the compressor mode and increasing the frequency to increase the liquid level of the inner cylinder, discharge more refrigerant into the system for circulation, and reducing the liquid level of the inner cylinder in the compressor mode and decreasing the frequency to reduce the amount of refrigerant discharged into the system for circulation, and increasing the suction height of the fluorine pump in the fluorine pump mode to avoid cavitation, thereby achieving the purpose of effective and intelligent control according to the needs of different working conditions, and accurately controlling the stored liquid to ensure that the circulation volume of the refrigeration system is in a better range, avoiding too much or too little refrigerant participating in the circulation in the refrigeration system. The storage state of the liquid refrigerant in the liquid storage tank can be changed according to the frequency change of the compressor; in the fluorine pump compression refrigeration double-circulation system, in the fluorine pump mode, the refrigerant gas at the outlet of the evaporator can be used to migrate the refrigerant liquid in the outer cylinder of the liquid storage tank to the inner cylinder, so that the height of the refrigerant liquid in the inner cylinder of the liquid storage tank meets the requirements of the suction height of the fluorine pump.

[0127] The liquid storage tank with adjustable liquid level control of the present invention can accurately control the stored liquid, thereby ensuring that the circulation volume of the refrigeration system is within an optimal range and avoiding too much or too little refrigerant participating in the circulation in the refrigeration system; the liquid level change in the liquid storage tank can be controlled by controlling the on and off of the three-way valve and / or the solenoid valve through the liquid level sensor, and this newly added function does not require changing the original control function of the refrigeration system.

[0128] In some embodiments,

[0129] A first throttle element 18 is further provided on the second bypass line 102 , and a second throttle element 19 is further provided on the third bypass line 103 .

[0130] The present invention can also throttle the gas drawn out from the outlet or inlet of the compressor by respectively arranging the first and second throttling members on the second and third bypass pipelines, thereby preventing excessive gas from entering or flowing out of the outer cylinder through the pressure taking pipe. Only a small amount of gas with a suitable pressure needs to be introduced or flowed out, thereby driving the liquid flow between the inner and outer cylinders when the frequency is increased or decreased, thereby reducing the impact on the system.

[0131] In some embodiments,

[0132] The first throttling member 18 is a capillary, and the second throttling member 19 is a capillary; the control valve 16 is a solenoid valve, which opens when the solenoid valve is powered on and closes when the solenoid valve is powered off; when the three-way valve 17 is powered on, the O end O is connected to the N end N, and the M end M is disconnected; when the three-way valve 17 is powered off, the O end O is connected to the M end M, and the N end N is disconnected.

[0133] This is the preferred structural form of the first and second throttle elements of the present invention, as well as the preferred structural form of the control valve and the preferred structural form of the three-way valve.

[0134] like Figure 4 As shown, the present invention provides a refrigeration system having the above-mentioned adjustable liquid storage tank, which is composed of a compressor, a condenser, a liquid storage tank, a throttle valve, and an evaporator connected in sequence; the outlet of the condenser is connected to the liquid inlet pipe of the liquid storage tank, and the inlet of the throttle valve is connected to the liquid outlet pipe of the liquid storage tank.

[0135] In a preferred embodiment, a low-pressure pressure-taking pipe is connected between the low-pressure suction pipe (from the evaporator outlet to the compressor suction port) of the refrigeration system and the pressure-taking pipe of the liquid storage tank; a capillary A (a second throttling device 19) is connected in series to the low-pressure pressure-taking pipe (the third bypass line 103); a high-pressure pressure-taking pipe is connected between the high-pressure exhaust pipe (from the compressor exhaust port to the condenser inlet) of the refrigeration system and the pressure-taking pipe of the liquid storage tank; a capillary B (a first throttling device 18) is connected in series to the high-pressure pressure-taking pipe (the second bypass line 102); the low-pressure pipeline between the capillary A and the pressure-taking pipe of the liquid storage tank, and the high-pressure pipeline between the capillary B and the pressure-taking pipe of the liquid storage tank, these two sections of pipelines are combined to form a pressure-taking pipeline, that is, the capillary A and the capillary B are connected together to the pressure-taking pipeline, and the other end of the pressure-taking pipeline is connected to the pressure-taking pipe of the liquid storage tank; the capillary A, the capillary B and the pressure-taking pipeline They are respectively connected to a three-way valve, the pressure-taking pipeline is connected to the common port O of the three-way valve, and the capillary A and the capillary B are respectively connected to the other two ports M and N; it is usually defined that when the power is off, the OM of the three-way valve is turned on / ON is closed, and when the power is on, the OM of the three-way valve is closed / ON is turned on; a solenoid valve is also connected in series on the pressure-taking pipeline between the three-way valve and the pressure-taking pipeline of the liquid storage tank, and the solenoid valve is preferably a normally closed solenoid valve when the power is off; the refrigeration system also includes a fluorine pump, a one-way valve A and a one-way valve B, the fluorine pump and the one-way valve A are connected in parallel and then connected in series to the pipeline between the liquid outlet pipe of the liquid storage tank and the throttle valve, and the flow direction of the fluorine pump and the one-way valve A is only allowed to flow from the liquid storage tank to the throttle valve; the one-way valve B is connected in parallel to bypass the compressor, the inlet and outlet of the one-way valve B are respectively connected to the suction port and exhaust port of the compressor, and the flow direction of the one-way valve B is only allowed to point from the inlet of the compressor to the outlet of the compressor.

[0136] In some embodiments,

[0137] It also includes a first branch 201 and a second branch 202. The first branch 201 is arranged in parallel at both ends of the compressor 8. A one-way valve B15 is arranged on the first branch 201, which only allows the fluid to flow from the evaporator 11 to the condenser 9. The branch where the fluorine pump 12 is located is the second branch 202. A one-way valve A14 is arranged on the pipeline parallel to the second branch 202, which only allows the fluid to flow from the liquid storage tank 13 to the throttle valve 10.

[0138] The present invention can also prevent the refrigerant at the compressor outlet from flowing back to the compressor inlet through the second branch in the compression mode through the arrangement of the above-mentioned branches and the one-way valves A and B. It can also prevent the refrigerant at the fluorine pump outlet from flowing to the fluorine pump inlet in the fluorine pump mode, thereby preventing the system circulation from failing to be established normally.

[0139] The present invention also provides a control method for the refrigeration system as described above, comprising:

[0140] A judgment step is to detect whether the refrigeration system is operating in a compression refrigeration mode or a fluorine pump refrigeration mode;

[0141] A detection step, when operating in a compression cooling mode, detecting whether the compressor is increasing or decreasing in frequency;

[0142] The control step is as follows: when the refrigeration system is operating in the compression refrigeration mode and the compressor is frequency-increasing, the control valve 16 is controlled to be opened, and the three-way valve 17 is controlled to make the O end O connected to the N end N, and the M end M is disconnected; when the compressor 8 is frequency-reduced, the control valve 16 is controlled to be opened, and the three-way valve 17 is controlled to make the O end O connected to the M end M, and the N end N is disconnected; when the refrigeration system is operating in the compression fluorine pump operation mode, the control valve 16 is controlled to be opened, and the three-way valve 17 is controlled to make the O end O connected to the M end M, and the N end N is disconnected.

[0143] This is a preferred step of the control method of the present invention, which can reduce the liquid level in the inner cylinder when the compressor mode is in frequency reduction, reduce the amount of discharged refrigerant entering the system for circulation, increase the suction height of the fluorine pump in the fluorine pump mode, avoid cavitation, and achieve the purpose of effective and intelligent control according to the needs of different working conditions, and can accurately control the stored liquid, thereby ensuring that the circulation volume of the refrigeration system is in a better range, avoiding too much or too little refrigerant participating in the circulation in the refrigeration system. The storage state of the liquid refrigerant in the liquid storage tank can be changed according to the frequency change of the compressor; in the fluorine pump compression refrigeration double-circulation system, in the fluorine pump mode, the refrigerant gas at the outlet of the evaporator can be used to migrate the refrigerant liquid in the outer cylinder of the liquid storage tank to the inner cylinder, so that the height of the refrigerant liquid in the inner cylinder of the liquid storage tank meets the suction height requirement of the fluorine pump.

[0144] In some embodiments,

[0145] When the liquid storage tank 13 is also provided with a liquid level gauge 6:

[0146] The detection step also detects the height of the liquid level inside the outer tube 2 by the liquid level meter 6;

[0147] The control step is that when the refrigeration system operates in the compression refrigeration mode, and the compressor is frequency-increased and the control steps of the control valve 16 and the three-way valve 17 are executed, if the liquid level detected by the liquid level meter 6 drops to a first preset height, the control valve 16 is first controlled to be closed, and then the three-way valve 17 is controlled to be powered off, so that the O terminal O is connected to the M terminal M, and the N terminal N is disconnected;

[0148] When the refrigeration system operates in the compression refrigeration mode, and the compressor is frequency-reduced and the control steps of the control valve 16 and the three-way valve 17 are executed, if the liquid level detected by the liquid level meter 6 rises to the second preset height, the control valve 16 is controlled to be closed, and the three-way valve 17 is maintained in the de-energized state;

[0149] When the refrigeration system operates in the fluorine pump refrigeration mode, if the liquid level detected by the liquid level meter 6 drops to a third preset height, the control valve 16 is controlled to be closed, and the three-way valve 17 is maintained in the de-energized state.

[0150] The present invention, through the detection of liquid level height and specific control form of the above-mentioned liquid level meter, can prevent the liquid level in the outer cylinder from dropping too low after the frequency-up control valve and the three-way valve are actuated, prevent the liquid level in the outer cylinder from rising too high after the frequency-down control valve and the three-way valve are actuated, and prevent the liquid level in the outer cylinder from dropping too low after the fluorine pump mode control valve and the three-way valve are actuated.

[0151] Figure 4 The working principle of the fluorine pump compression double cycle refrigeration system:

[0152] A) Compression refrigeration mode - the fluorine pump is turned off and the compressor is turned on. Because there is a reverse pressure difference at both ends of the one-way valve B, it cannot be conducted; the main circulation flow path of the refrigerant is: compressor → condenser → liquid storage tank → one-way valve A → throttle valve → evaporator → compressor.

[0153] When the compressor frequency is increased, the required system circulation volume is large, so it is hoped that the refrigerant liquid in the outer cylinder of the liquid storage tank can be squeezed into the inner cylinder to participate in the system circulation: the solenoid valve is turned on and powered on, and OM is closed / ON is turned on when the three-way valve is powered on. Then a small part of the high-temperature and high-pressure refrigerant gas enters the outer cylinder space of the liquid storage tank through the capillary B, the three-way valve ON channel, and the solenoid valve. As the amount of gas in the outer cylinder space increases, the refrigerant pressure P1 in the outer cylinder space increases, and then the one-way valve on the left side of the liquid storage tank is opened (the one-way valve from the outer cylinder to the inner cylinder). At least part of the refrigerant liquid in the outer cylinder flows into the inner cylinder from the opened one-way valve until the liquid level gauge detects that the liquid level in the outer cylinder of the liquid storage tank has dropped to a suitable position. The solenoid valve is powered off first and then the three-way valve (to avoid the following situation: the three-way valve is powered off first and OM is turned on. At this time, the solenoid valve has not been powered off, and there is a huge pressure difference between the high pressure of the outer cylinder space of the liquid storage tank and the low pressure between the suction port of the compressor, which can easily cause the liquid level in the outer cylinder space of the liquid storage tank to rise).

[0154] When the compressor frequency is reduced, the required system circulation volume is small, so it is hoped that the refrigerant liquid in the inner cylinder of the liquid storage tank is squeezed into the outer cylinder for storage to reduce the circulation volume of the refrigeration system: the solenoid valve is turned on and the three-way valve is kept off, then OM is turned on / ON is closed. Under the suction action of the low-pressure suction port of the compressor, the upper refrigerant gas in the outer cylinder space enters the compressor through the solenoid valve, the three-way valve OM channel and the capillary A respectively. As the refrigerant gas in the upper space of the outer cylinder decreases, the refrigerant pressure P1 of the outer cylinder decreases, and then the one-way valve on the right side of the liquid storage tank (the one-way valve flowing from the inner cylinder to the outer cylinder) is opened, and at least part of the refrigerant liquid in the inner cylinder flows from the opened one-way valve into the outer cylinder until the liquid level gauge detects that the liquid level in the outer cylinder of the liquid storage tank rises to a suitable position, and then the solenoid valve is turned off. If there is no closing action of the solenoid valve, at least one channel of the three-way valve will be connected to the pressure-taking pipe of the liquid storage tank in any state, thereby affecting the pressure change in the outer cylinder space of the liquid storage tank, which is not allowed. Therefore, it is necessary to add a solenoid valve to block this action relationship to ensure the normal operation of the refrigeration system.

[0155] B) Fluorine pump refrigeration mode - the fluorine pump is turned on and the compressor is turned off. The fluorine pump outlet is in a high-pressure state and the fluorine pump inlet is in a low-pressure state. Therefore, there is a reverse pressure difference at both ends of the one-way valve A and it cannot be conducted; the main circulation flow path of the refrigerant is: fluorine pump → throttle valve → evaporator → one-way valve B → condenser → liquid storage tank → fluorine pump.

[0156] Since the fluorine pump mode requires the largest amount of refrigerant to participate in the circulation (as explained in the background technology, the main reason is to increase the liquid level in the liquid storage tank, ensure the suction safety of the fluorine pump and avoid cavitation of the fluorine pump), it is necessary to transfer the refrigerant liquid in the outer cylinder space of the liquid storage tank to the inner cylinder as much as possible to participate in the circulation of the refrigeration system.

[0157] It is well known that the fluid pressure gradually decreases with the direction of fluid flow, so it can be known that the gas pressure at the evaporator outlet, i.e., the inlet of capillary A and the inlet of check valve B, must be greater than the refrigerant pressure in the liquid storage tank (the liquid storage tank is located at the inlet end of the fluorine pump, which is basically the lowest pressure pipe section of the entire system); at this time, the three-way valve remains in the de-energized state, and OM is on / ON is closed. Opening the solenoid valve can allow part of the refrigerant gas coming out of the evaporator to enter the outer cylinder space of the liquid storage tank. Therefore, the check valve on the left side of the liquid storage tank can be opened to force the refrigerant liquid in the outer cylinder space to enter the inner cylinder space. When the liquid level gauge detects that the liquid level in the outer cylinder of the liquid storage tank is at the lowest state, the solenoid valve is closed, and the left check valve will be closed, thereby preventing the refrigerant liquid in the inner cylinder space from entering the outer cylinder space, ensuring that the outer cylinder space basically does not store refrigerant liquid, and meeting the circulating filling volume under the fluorine pump refrigeration mode.

[0158] 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 liquid storage tank capable of adjusting the amount of stored liquid, characterized in that: include: An inner cylinder (1) and an outer cylinder (2), wherein the inner cylinder (1) is located inside the outer cylinder (2), and the outer cylinder (2) is sleeved on the outer circumference of the inner cylinder (1). An outlet pipe (3) is arranged at the bottom of the inner cylinder (1) so as to be able to discharge the fluid in the inner cylinder (1). A valve structure (4) is arranged between the inner cylinder (1) and the outer cylinder (2). In a compression refrigeration mode, the valve structure (4) can introduce the fluid in the outer cylinder (2) into the inner cylinder (1) when the compressor frequency is increased, so that the amount of fluid discharged from the outlet pipe (3) increases; in a compression refrigeration mode, the valve structure (4) can also introduce the fluid in the inner cylinder (1) into the outer cylinder (2) when the compressor frequency is reduced, so that the amount of fluid discharged from the outlet pipe (3) decreases; in a fluorine pump refrigeration mode, the valve structure (4) can introduce the fluid in the outer cylinder (2) into the inner cylinder (1), so that the liquid level in the inner cylinder (1) increases.

2. The liquid storage tank with adjustable storage amount of liquid according to claim 1, characterized in that: A pressure-taking port is provided at the top of the outer cylinder (2), and a pressure-taking pipe (5) is inserted into the pressure-taking port so that the interior of the outer cylinder (2) is connected to an external pressure gas source; in the compression refrigeration mode and when the compressor frequency is increased, the pressure-taking pipe (5) can pass gas with a pressure greater than the internal pressure of the inner cylinder (1) into the interior of the outer cylinder (2); in the compression refrigeration mode and when the compressor frequency is decreased, the pressure-taking pipe (5) can suck the gas inside the outer cylinder (2) and make the pressure inside the outer cylinder (2) lower than the pressure inside the inner cylinder (1); in the fluorine pump refrigeration mode, the pressure-taking pipe (5) can pass gas with a pressure greater than the internal pressure of the inner cylinder (1) into the interior of the outer cylinder (2).

3. The liquid storage tank with adjustable storage amount of liquid according to claim 2, characterized in that: It also includes an inlet pipe (7), which is inserted into the inner cylinder (1) from above the inner cylinder (1) so as to allow fluid to flow into the inner cylinder (1); A liquid level meter (6) is also provided inside the outer cylinder (2) to detect the height of the liquid level inside the outer cylinder (2).

4. The liquid storage tank with adjustable storage amount of liquid according to claim 2 or 3, characterized in that: The valve structure (4) comprises a first one-way valve (41) and a second one-way valve (42); the first one-way valve (41) is arranged on the wall of the inner cylinder (1) so as to allow only the fluid in the outer cylinder (2) to enter the inner cylinder (1) through the first one-way valve (41); and the second one-way valve (42) is arranged on the wall of the inner cylinder (1) so as to allow only the fluid in the inner cylinder (1) to enter the outer cylinder (2) through the second one-way valve (42).

5. The liquid storage tank with adjustable storage amount of liquid according to claim 4, characterized in that: The first one-way valve (41) and the second one-way valve (42) have the same valve structure, and both comprise a valve body (43), a large channel (44) and a small channel (45); the valve body (43) is arranged on the wall of the inner tube (1); the large channel (44) and the small channel (45) are both opened inside the valve body (43); the flow cross-sectional area of ​​the large channel (44) is larger than the flow cross-sectional area of ​​the small channel (45), so that the fluid can only flow from the small channel (45) to the large channel (44); the first one-way valve (41) is arranged so that its small channel (45) is in communication with the cavity of the outer tube (2), and its large channel (44) is in communication with the cavity of the inner tube (1); the second one-way valve (42) is arranged so that its small channel (45) is in communication with the cavity of the inner tube (1), and its large channel (44) is in communication with the cavity of the outer tube (2).

6. The liquid storage tank with adjustable storage amount of liquid according to claim 5, characterized in that: The valve structure further comprises a valve core (46) and an elastic structure (47); one end of the small channel (45) is located at one axial end of the valve body (43); the other end of the small channel (45) extends toward the interior of the valve body (43); one end of the large channel (44) is communicated with the other end of the small channel (45); the other end of the large channel (44) is communicated with the other axial end of the valve body (43); the valve core (46) and the elastic structure (47) are arranged in the large channel (44); the valve core (46) is relatively close to the small channel (45); the elastic structure (47) is relatively far away from the small channel (45); and one end of the elastic structure (47) is in contact with the small channel (45). The valve core (46) is connected to the large channel (44), and the other end of the elastic structure (47) is fixed, so that an elastic thrust can be applied to the valve core (46). When the pressure in the small channel (45) is greater than the pressure in the large channel (44) plus the elastic thrust, the valve core (46) is pushed to move in a direction away from the small channel (45), so that the small channel (45) and the large channel (44) are connected. When the pressure in the large channel (44) plus the elastic thrust is greater than the pressure in the small channel (45), the valve core (46) is pushed to block the connection between the small channel (45) and the large channel (44), so that the small channel (45) and the large channel (44) are not connected.

7. The liquid storage tank with adjustable storage amount of liquid according to claim 6, characterized in that: The position where the large channel (44) connects with the small channel (45) is set as a transition channel with a trapezoidal longitudinal section, the valve core (46) includes a first valve stem (48) and a second valve stem (49), the first valve stem (48) can be inserted into the small channel (45) and reciprocate in the small channel (45), one end of the first valve stem (48) is connected to one end of the second valve stem (49), the cross-sectional area of ​​the second valve stem (49) is larger than the cross-sectional area of ​​the first valve stem (48), and the second valve stem (49) is set in the large channel (44) and can also reciprocate in the large channel (44), and the position where the second valve stem (49) connects with the first valve stem (48) is set as a transition structure with a trapezoidal longitudinal section, and the transition structure cooperates with the transition channel; A limiting structure (410) is provided in a portion of the large channel (44) away from the small channel (45), one end of the limiting structure (410) is abutted or fixedly connected to one end of the elastic structure (47), the other end of the limiting structure (410) can extend to the other end surface of the valve body (43), and the limiting structure (410) has a hollow flow channel (411) inside to form a channel for fluid circulation.

8. The liquid storage tank with adjustable storage amount of liquid according to claim 6, characterized in that: The first one-way valve (41) and the second one-way valve (42) are both cylindrical structures, and their central axes are arranged in the horizontal direction. The inner tube (1) and the outer tube (2) are also cylindrical structures, and their central axes are arranged in the vertical direction.

9. A refrigeration system, characterized in that: It comprises a liquid storage tank (13) as described in any one of claims 2 to 8, and also comprises a compressor (8), a condenser (9), a throttle valve (10), an evaporator (11) and a fluorine pump (12), wherein the throttle valve (10) is arranged between the condenser (9) and the evaporator (11), the liquid storage tank (13) is arranged between the condenser (9) and the throttle valve (10), the outlet end of the compressor (8) is connected to the condenser (9), the inlet end of the compressor (8) is connected to the evaporator (11), and the fluorine pump (12) is arranged in parallel on the pipeline between the throttle valve (10) and the liquid storage tank (13).

10. The refrigeration system according to claim 9, characterized in that: The evaporator (11) further comprises a first bypass pipeline (101), a second bypass pipeline (102) and a third bypass pipeline (103); one end of the first bypass pipeline (101) is connected to the pressure taking pipeline (5); the other end of the first bypass pipeline (101) can be connected to the outlet end of the compressor (8) or to the inlet end of the condenser (9) through the second bypass pipeline (102); the other end of the first bypass pipeline (101) can also be connected to the inlet end of the compressor (8) or to the outlet end of the evaporator (11) through the third bypass pipeline (103), so that when the frequency of the compressor (8) is increased, the second bypass pipeline (102) can be used to bypass the third bypass pipeline (103) to the outlet end of the evaporator (11). 02), the first bypass pipeline (101) and the pressure-taking pipe (5) are used to introduce gas with a pressure greater than the internal pressure of the inner cylinder (1) into the outer cylinder (2); when the compressor (8) is reduced in frequency, the gas in the outer cylinder (2) can be sucked through the third bypass pipeline (103), the first bypass pipeline (101) and the pressure-taking pipe (5) to reduce the pressure inside the outer cylinder (2) to a level lower than the pressure inside the inner cylinder (1); and in the fluorine pump operation mode, the gas with a pressure greater than the internal pressure of the inner cylinder (1) can be introduced into the outer cylinder (2) through the third bypass pipeline (103), the first bypass pipeline (101) and the pressure-taking pipe (5).

11. The refrigeration system according to claim 10, characterized in that: When the frequency of the compressor (8) is increased, one end of the second bypass pipeline (102) is connected to the outlet end of the compressor (8) to introduce gas from the outlet end of the compressor (8); when the frequency of the compressor (8) is decreased, one end of the third bypass pipeline (103) is connected to the inlet end of the compressor (8) to draw out at least part of the gas in the outer cylinder (2) to the inlet end of the compressor (8); in the fluorine pump operation mode, one end of the third bypass pipeline (103) is connected to the outlet end of the evaporator (11) to introduce gas from the outlet end of the evaporator (11).

12. The refrigeration system according to claim 11, characterized in that: The invention also comprises a control valve (16) and a three-way valve (17), wherein the control valve (16) is arranged on the first bypass pipeline (101), and the three-way valve (17) is arranged at a position where the first bypass pipeline (101), the second bypass pipeline (102) and the third bypass pipeline (103) are connected together, and the three-way valve (17) comprises an O end (O), an N end (N) and an M end (M), wherein the O end (O) is connected to the other end of the first bypass pipeline (101), the N end (N) is connected to one end of the second bypass pipeline (102), and the M end (M) is connected to one end of the third bypass pipeline (103), and the three-way valve (17) can switch between a first state and a second state, wherein the first state is that the O end (O) is connected to the N end (N) and the M end (M) is disconnected, and the second state is that the O end (O) is connected to the M end (M) and the N end (N) is disconnected; When the compressor (8) increases its frequency, the control valve (16) is controlled to be opened, and at the same time, the three-way valve (17) is controlled so that the O end (O) is connected to the N end (N), and the M end (M) is disconnected; when the compressor (8) decreases its frequency, the control valve (16) is controlled to be opened, and at the same time, the three-way valve (17) is controlled so that the O end (O) is connected to the M end (M), and the N end (N) is disconnected; in the fluorine pump operation mode, the control valve (16) is controlled to be opened, and at the same time, the three-way valve (17) is controlled so that the O end (O) is connected to the M end (M), and the N end (N) is disconnected.

13. The refrigeration system according to claim 12, characterized in that: A first throttling element (18) is also provided on the second bypass pipeline (102), and a second throttling element (19) is also provided on the third bypass pipeline (103).

14. The refrigeration system according to claim 13, characterized in that: The first throttling element (18) is a capillary tube, and the second throttling element (19) is a capillary tube; the control valve (16) is an electromagnetic valve, which is opened when the electromagnetic valve is powered on and closed when the electromagnetic valve is powered off; when the three-way valve (17) is powered on, the O end (O) is connected to the N end (N) and the M end (M) is disconnected; when the three-way valve (17) is powered off, the O end (O) is connected to the M end (M) and the N end (N) is disconnected.

15. The refrigeration system according to claim 9, characterized in that: The invention also comprises a first branch (201) and a second branch (202), wherein the first branch (201) is arranged in parallel at both ends of the compressor (8), a one-way valve B (15) is arranged on the first branch (201), and only allows the fluid to flow from the evaporator (11) to the condenser (9), the branch where the fluorine pump (12) is located is the second branch (202), and a one-way valve A (14) is arranged on the pipeline in parallel with the second branch (202), and only allows the fluid to flow from the liquid storage tank (13) to the throttle valve (10).

16. A method for controlling a refrigeration system according to any one of claims 12 to 14, characterized in that: include: A judgment step is to detect whether the refrigeration system is operating in a compression refrigeration mode or a fluorine pump refrigeration mode; A detection step, when operating in a compression cooling mode, detecting whether the compressor is increasing or decreasing in frequency; The control step comprises: when the refrigeration system is operating in a compression refrigeration mode and the compressor is frequency-increasing, the control valve (16) is controlled to be opened, and the three-way valve (17) is controlled to make the O end (O) connected to the N end (N) and the M end (M) disconnected; when the compressor (8) is frequency-reducing, the control valve (16) is controlled to be opened, and the three-way valve (17) is controlled to make the O end (O) connected to the M end (M) and the N end (N) disconnected; when the refrigeration system is operating in a fluorine pump operation mode, the control valve (16) is controlled to be opened, and the three-way valve (17) is controlled to make the O end (O) connected to the M end (M) and the N end (N) disconnected.

17. The control method according to claim 16, characterized in that: When the liquid storage tank (13) is also provided with a liquid level meter (6): The detection step also detects the height of the liquid level inside the outer cylinder (2) by means of the liquid level meter (6); The control step is as follows: when the refrigeration system is operating in a compression refrigeration mode, and the compressor is frequency-increased and the control steps of the control valve (16) and the three-way valve (17) are executed, if the liquid level detected by the liquid level meter (6) drops to a first preset height, the control valve (16) is first controlled to be closed, and then the three-way valve (17) is controlled to be powered off, so that the O terminal (O) is connected to the M terminal (M), and the N terminal (N) is disconnected; When the refrigeration system operates in a compression refrigeration mode, and the compressor is frequency-reduced and the control steps of the control valve (16) and the three-way valve (17) are executed, if the liquid level detected by the liquid level meter (6) rises to a second preset height, the control valve (16) is controlled to be closed, and the three-way valve (17) is maintained in a power-off state; When the refrigeration system operates in the fluorine pump refrigeration mode, if the liquid level detected by the liquid level meter (6) drops to a third preset height, the control valve (16) is controlled to close, and the three-way valve (17) is maintained in an off-state.

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