CN115523671A - Self-cascade refrigeration system and low-temperature cabinet - Google Patents

Abstract

The invention discloses a self-cascade refrigeration system and a low-temperature cabinet, wherein the self-cascade refrigeration system comprises: a self-cascade refrigeration loop: the expansion tank is connected with the refrigerant gas path and used for decompressing the system, a connector communicated with the inner space of the expansion tank is formed at the bottom of the expansion tank, and the suction side of the compressor is connected with the connector through a suction channel of the compressor. The invention solves the problem of difficult oil return of the compressor in the self-cascade system in the prior art.

Description

Self-cascading refrigeration system and low-temperature cabinet

technical field

The invention relates to the field of cryogenic technology, in particular to a self-cascading refrigeration system for ultra-low temperature and an improvement in the structure of a low-temperature cabinet with the self-cascading refrigeration system.

Background technique

The existing ultra-low temperature self-cascading system structure is formed by connecting a compressor, an oil separator, a condenser, a multi-stage gas-liquid separator, a multi-stage heat exchanger, a regenerator and an evaporator.

The high-temperature and high-pressure gaseous refrigerant discharged from the compressor passes through the oil separator for gas-oil separation and then enters the condenser for condensation. The condensed refrigerant enters the first-stage gas-liquid separator for split flow. The split gas refrigerant directly passes through the gas-liquid The refrigerant gas pipe configured by the separator flows into its corresponding heat exchanger.

The liquid refrigerant is mixed with the liquid refrigerant returned from the return air branch of the next-stage heat exchanger, and then enters the heat exchanger for heat exchange with the gaseous refrigerant, and the heat-exchanged refrigerant will enter the next-stage gas-liquid separator .

Then it enters the heat exchanger of the next stage for heat exchange. The refrigerant is continuously iteratively cooled through the multi-stage heat exchanger. The refrigerant in the final heat exchanger enters the regenerator, and then enters the Evaporation is carried out in the evaporator to reach the final required evaporation temperature to achieve ultra-low temperature refrigeration.

In order to achieve pressure relief, an expansion tank is usually connected to the refrigerant gas path of the entire system. During pressure relief, the gaseous refrigerant in the system can be discharged into the expansion tank to achieve pressure relief. After pressure relief, it is brought into the expansion tank by the refrigerant. The lubricating oil in the tank is mainly concentrated at the bottom of the expansion tank.

When the existing expansion tank is installed, it is generally provided with an upper suction port and a lower exhaust port, and the corresponding suction channel of the compressor is connected to the upper suction port. Therefore, it is difficult for the compressor to suck out the lubricating oil located at the bottom of the expansion tank, and there is a problem of difficulty in oil return.

Contents of the invention

The invention aims at the problem of difficult oil return from the compressor in the self-cascade system in the prior art;

The invention proposes a new type of low-temperature self-cascading system, which has an interface at the bottom of the expansion tank to communicate with the suction channel of the compressor, so that the lubricating oil can be smoothly sucked out by the compressor, and the problem of difficult oil return from the compressor is solved .

In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solutions to achieve:

A self-cascading refrigeration system comprising:

Self-cascading refrigeration circuit: it is formed by connecting a compressor, an oil separator, a condenser, a multi-stage gas-liquid separator, a multi-stage heat exchanger, a regenerator, and an evaporator through a refrigerant liquid circuit and a refrigerant gas circuit;

The expansion tank is connected to the refrigerant gas circuit to release the pressure of the system;

An interface portion communicating with the inner space of the expansion tank is formed at the bottom of the expansion tank, and the suction side of the compressor is connected to the interface portion through a compressor suction channel.

In some embodiments of the present application, the interface part is an interface pipe, which is inserted at the bottom of the expansion tank, and the expansion tank is connected to the refrigerant gas path through a pressure relief channel, and the pressure relief channel , the compressor suction channel are all in communication with the mouthpiece.

In some embodiments of the present application, the interface part includes a first interface and a second interface, the first interface and the second interface are both arranged at the bottom of the expansion tank, and the first interface and the drain The pressure channel is connected, and the second interface is connected with the compressor suction channel.

In some embodiments of the present application, a throttling component for throttling and reducing pressure is provided on the suction channel of the compressor.

In some embodiments of the present application, the throttling component is a throttling capillary.

In some embodiments of the present application, the refrigerant gas path includes a refrigerant bronchus configured with a gas-liquid separator and connected to its corresponding heat exchanger;

The pressure relief passage is connected to the expansion tank and the refrigerant gas pipe configured by one of the gas-liquid separators below the primary gas-liquid separator, and a switch for controlling the on-off of the pressure relief passage is provided on the pressure relief passage. control parts.

Further, a filter element is also arranged on the compressor suction passage.

A kind of low-temperature cabinet includes a box shell, and also includes the self-cascading refrigeration system described in the above technical solution and:

a first partition part, the first partition part is arranged in the case shell and divides the case case to form a first chamber and a second chamber;

The second partition component is arranged in the first chamber, and divides the first chamber into a compressor compartment and an equipment compartment, and the equipment compartment is arranged above the compressor compartment, and in the equipment compartment The expansion tank is provided.

Further, a clamping part is provided on the second partition part, the expansion tank is clamped in the clamping part, and its interface part faces the compressor compartment.

Further, a clamping part for clamping and fixing the expansion tank is also included, and the clamping part is arranged on the second partition part.

Compared with prior art, advantage and positive effect of the present invention are:

In the present invention, an interface is provided at the bottom of the expansion tank. When the expansion tank is placed normally, the oil flowing back to the expansion tank will be concentrated at the bottom of the expansion tank due to gravity, and the suction channel of the compressor communicates with the space at the bottom of the expansion tank through the interface. , so that when the compressor absorbs oil, the oil droplets accumulated at the bottom of the expansion tank will be more easily sucked into the compressor suction channel and enter the interior of the compressor, which solves the problem of difficult oil return from the compressor.

Other characteristics and advantages of the present invention will become clearer after reading the detailed description of the present invention in conjunction with the accompanying drawings.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required in the embodiments. Apparently, the drawings in the following description are some embodiments of the present invention.

For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

Fig. 1 is a system schematic diagram of the first embodiment of the corresponding interface part of the self-cascading refrigeration system in the embodiment of the present invention;

Fig. 2 is a system schematic diagram of a second embodiment of the corresponding interface part of the self-cascading refrigeration system in the embodiment of the present invention.

Fig. 3 is the structural representation 1 of low-temperature cabinet in the embodiment of the present invention;

Fig. 4 is the structural representation 2 of low-temperature cabinet in the embodiment of the present invention;

Fig. 5 is a schematic structural view 3 of a low-temperature cabinet in an embodiment of the present invention;

Fig. 6 is a structural diagram of a first embodiment of the corresponding self-cascading refrigeration system interface part of the low-temperature cabinet in the embodiment of the present invention.

Among them, compressor-110;

Oil separator - 120;

Condenser - 130;

Regenerator - 140;

Evaporator - 150;

Multi-stage gas-liquid separator-200;

First stage gas-liquid separator-210;

Final gas-liquid separator-220;

Multi-stage heat exchanger-300;

First stage heat exchanger-310;

Final stage heat exchanger-320;

Expansion tank - 400;

Interface-410;

first interface-411;

Second interface-412;

Compressor suction channel-500;

Pressure relief channel-600;

Throttle part-700;

filter element-800;

Box shell-910;

First Chamber - 911;

Compressor compartment-9111;

Equipment warehouse-9112;

Second Chamber - 912

First partition member - 920;

Second partition member - 930;

Clamping part-931;

Clamping part - 940.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In describing the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", The orientations or positional relationships indicated by "top", "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying References to devices or elements must have a particular orientation, be constructed, and operate in a particular orientation and therefore should not be construed as limiting the invention.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. connected, or integrally connected.

Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations. In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in an appropriate manner.

The terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features.

In the description of the present invention, unless otherwise specified, "plurality" means two or more.

The present invention proposes an embodiment of a self-cascading refrigeration system, including:

Self-cascading refrigeration circuit, which consists of compressor 110, oil separator 120, condenser 130, multi-stage gas-liquid separator 200, multi-stage heat exchanger 300, regenerator 140, evaporator 150 through the refrigerant gas path and refrigerant A fluid connection is formed.

When specifically connected, the exhaust side of the compressor 110 is connected to the oil separator 120, and the gas outlet of the oil separator 120 is connected to the condenser 130. The oil separator 120 is mainly used to steam the refrigerant and oil flowing out of the compressor 110. and oil separation.

After the refrigerant discharged from the compressor 110 passes through the oil separator 120 , the separated gaseous refrigerant enters the condenser 130 .

The oil separator 120 is also correspondingly connected to the air return side of the compressor 110 through pipelines for returning the oil separated by the oil separator 120 to the compressor 110 .

The refrigerant enters the condenser 130 to be condensed, and the condensed refrigerant enters the multi-stage heat exchanger 300 for cascading.

Each heat exchanger corresponds to a gas-liquid separator, and the multi-stage heat exchanger 300 corresponds to the multi-stage gas-liquid separator 200 .

Each stage of the gas-liquid separator is equipped with a refrigerant branch liquid pipe and a refrigerant branch pipe 170 , which are connected to the corresponding heat exchanger through the refrigerant branch liquid pipe and the refrigerant branch pipe 170 .

The first-stage heat exchanger 310 communicates with the compressor 110 through the total air return path, and the corresponding first-stage gas-liquid separator 210 of the first-stage heat exchanger 310 is connected with the condenser 130 .

The rest of the gas-liquid separators located below the first stage are correspondingly connected to the heat exchanger of the upper stage, and the refrigerant of the heat exchanger of the upper stage is passed through the refrigerant branch liquid pipe and the refrigerant branch pipe 170 to separate the liquid refrigerant and the gaseous refrigerant. into its corresponding heat exchanger.

The remaining gas-liquid separators below the first stage include an intermediate gas-liquid separator and a final gas-liquid separator 220 .

The remaining heat exchangers below the primary heat exchanger 310 include: an intermediate heat exchanger and a final heat exchanger 320 .

When the self-cascade refrigeration system is a two-stage cascade refrigeration system, the multi-stage heat exchanger 300 corresponds to include a first-stage heat exchanger 310 and a final-stage heat exchanger 320, and the multi-stage gas-liquid separator 200 corresponds to a first-stage gas Liquid separator 210 and final gas-liquid separator 220.

Each heat exchanger communicates with the refrigerant branch liquid pipe corresponding to the upper heat exchanger through the air return branch, so as to combine the returning refrigerant with the liquid refrigerant separated from the corresponding upper gas-liquid separator.

The regenerator 140 is connected to the final heat exchanger 320 and the evaporator 150 in the remaining heat exchangers, and is used to transfer the refrigerant flowing out of the final heat exchanger 320 to the evaporator 150 for further condensation and cooling .

The return air branch corresponding to the regenerator 140 is connected to the refrigerant branch liquid pipe of the final stage heat exchanger 320 for returning the refrigerant.

The refrigerant discharged from the compressor 110 is separated by the oil separator 120, enters the condenser 130, and then enters the primary gas-liquid separator 210 for gas-liquid separator.

The separated gas refrigerant is mixed with the liquid refrigerant passing through the next-stage return air branch and the diverted refrigerant, and then enters the first-stage heat exchanger 310 for heat exchange, and the heat-exchanged refrigerant then enters the next-stage gas-liquid separator. The heat exchange is carried out, and the cycle is continued in sequence. The multi-stage heat exchanger 300 is continuously stacked to condense the refrigerant, and finally enters the regenerator 140 and the evaporator 150, and reaches the final temperature through the evaporator 150.

One end of the pressure relief passage 600 is connected to the expansion tank 400, and the other end is connected to the refrigerant gas path of the entire system to release the pressure of the system.

The refrigerant gas path is composed of all the refrigerant flow paths through which the refrigerant flows when the entire system is running, and includes a plurality of refrigerant bronchial pipes 170 corresponding to the gas-liquid separators.

An interface portion 410 communicating with the inner space of the expansion tank 400 is formed at the bottom of the expansion tank 400 .

The bottom in this embodiment refers to the side of the expansion tank 400 facing the ground when it is placed normally.

The compressor suction passage 500 is connected between the suction side of the compressor 110 and the interface part 410 .

When the expansion tank 400 is placed normally, the lubricating oil flowing back into the expansion tank 400 through the pressure relief passage 600 will concentrate and accumulate at the bottom of the expansion tank 400 due to gravity, and the amount of lubricating oil is large.

Since the interface part 410 is arranged at the bottom of the expansion tank 400 and communicates with the compressor suction passage 500, the lubricating oil in the expansion tank 400 will enter into the compressor suction passage 500 more easily when the compressor 110 sucks oil. The problem of difficult oil return of the compressor 110 is solved.

In a specific arrangement, the compressor 110 in this embodiment may be arranged above or below the expansion tank 400 .

When the compressor 110 is arranged under the expansion tank 400 , the oil located at the bottom of the expansion tank 400 may return to the oil under the action of gravity and the suction force of the compressor 110 during oil return.

Of course, the compressor 110 can also be arranged above the expansion tank 400 , as long as the interface part 410 is located at the bottom of the expansion tank 400 , it can ensure smooth oil return when the compressor 110 sucks air.

In some embodiments of the present application, as shown in Figure 1 and Figure 6: the interface part 410 is an interface pipe, which is inserted at the bottom of the expansion tank 400, and the pressure relief passage 600, compressor suction The air passage 500 is configured as a pressure relief pipe and a compressor suction pipe, both of which communicate with the interface pipe.

That is, when connecting, the pressure relief passage 600 is connected to the mouthpiece, and the compressor suction passage 500 is also connected to the mouthpiece correspondingly. The mouthpiece, the compressor suction passage 500 and the pressure relief passage 600 form a three-way passage structure. The connection structure is simplified.

When pressure relief is required, the conduction of the pressure relief passage 600 is controlled. At this time, the refrigerant and oil will pass through the pressure relief passage 600 and then flow back into the expansion tank 400 through the interface pipe, so as to relieve the pressure of the entire system.

When it is necessary to return oil, the compressor suction channel 500 is controlled to conduct, and the compressor 110 operates to suck the expanding lubricating oil and gaseous refrigerant into its interior through the mouthpiece.

In some embodiments of the present application, as shown in FIG. 2 : the interface part 410 includes a first interface 411 and a second interface 412, and the first interface 411 and the second interface 412 are both arranged on the expansion Tank 400 bottom.

The first interface 411 is connected to the pressure relief passage 600 , and the second interface 412 is connected to the compressor suction passage 500 .

The first port 411 and the second port 412 are arranged in parallel, the pressure relief channel 600 can communicate with the expansion tank 400 through the first port 411, and the compressor suction channel 500 can correspondingly pass through the second port 412 and the expansion tank 400 connected.

Certainly, in some embodiments, the interface portion 410 may also be configured as a first interface pipe and a second interface pipe, both of which may be connected to the bottom of the expansion tank 400 .

Alternatively, the first mouthpiece and the second mouthpiece communicate with each other, and at the same time, a connecting pipe is led out from the bottom of the expansion tank 400, and the first mouthpiece, the second mouthpiece and the connecting pipe form a three-way connecting pipe structure.

In some embodiments of the present application: the interface portion 410 is an opening, and one is provided at the bottom of the expansion tank 400, and the pressure relief port is provided at the top of the expansion tank 400, and the pressure relief channel 600 is connected to the pressure relief port. The machine suction passage 500 is connected to an opening at the bottom of the expansion tank 400 .

That is, setting the pressure relief port above can also make the oil return of the compressor 110 easy.

In some embodiments of the present application, a throttling component 700 for throttling and reducing pressure is provided on the compressor suction passage 500 .

By setting the throttling component 700, the gaseous refrigerant in the pressure relief passage 600 can be throttled and decompressed when it flows back to the compressor 110 side, so that the gaseous refrigerant that is depressurized into the expansion tank 400 will not be rapidly Enter the compressor 110, but slowly enter the compressor 110, so that the compressor 110 has enough time to establish the balance of the entire self-cascading refrigeration system.

In addition, after the pressure release of the expansion tank 400, if the throttling member 700 is not provided on the compressor suction passage 500, the gaseous refrigerant will quickly enter the compressor 110 through the compressor suction passage 500, and the compressor 110 has just After the depressurization is completed, it is pressurized again, which will cause the compressor 110 to be directly stuck or the compressor 110 to perform frequent depressurization, so that the entire system cannot be refrigerated.

The throttle component 700 may correspond to an electronic expansion valve or a throttle capillary.

If the throttling component 700 is an electronic expansion valve, the throttling effect can be realized by adjusting the opening of the electronic expansion valve during use.

Of course, in some embodiments, it is also possible to control the on-off of the channel by setting a control component on the compressor suction channel 500 correspondingly, so as to prevent the gaseous refrigerant in the expansion tank 400 from entering the compressor 110 rapidly, and the control component can Choose a solenoid valve.

In some preferred embodiments of the present application, the throttling component 700 is a throttling capillary.

When the pressure is released, the amount of oil flowing back into the expansion tank 400 through the pressure relief channel 600 is relatively small, and it is difficult to extract the oil back from the compressor suction channel 500 .

If a throttling capillary is set on the compressor suction channel 500, it will make it easier for the compressor 110 to suck the oil in the expansion tank 400 into its interior, making it easier to return the oil, mainly due to the corresponding cross-section of the throttling capillary. The small area makes it easier to form an oil seal when absorbing oil.

In addition, if the throttling component 700 uses a throttling capillary, the entire compressor suction passage 500 can always be in a normally open state, so that there is no need to set a separate control program to separately control the on-off of the compressor suction passage 500, Simplifies overall system control.

In some embodiments of the present application, a filter element 800 is also provided on the compressor suction passage 500 .

The filter element 800 can be a filter, which is used to filter impurities in the refrigerant flowing on the compressor suction passage 500, which can prevent the compressor suction passage 500 from being blocked.

In order to make the lubricating oil in the entire low-temperature self-cascading system flow into the expansion tank 400 as little as possible, reduce the loss of oil in the system, and ensure the normal operation of the entire system.

When set, the pressure relief channel 600 is connected to the refrigerant bronchus 170 corresponding to one of the gas-liquid separators below the primary gas-liquid separator 210 .

And in order to ensure that it can release pressure, it should be connected to the high-pressure end of the refrigerant bronchus 170, that is, the end that is not throttled by the throttling element.

The refrigerant in the refrigerant branch pipe 170 below the primary gas-liquid separator 210 has at least been separated by the oil separator 120 and the primary gas-liquid separator 210 .

After multiple times of oil separation, the corresponding lubricating oil content on the refrigerant bronchus 170 is particularly small, and when the pressure is released, the lubricating oil carried by the gaseous refrigerant into the expansion tank 400 is also less, avoiding excessive lubricating oil entering into the system and affect the normal operation of the system.

Embodiment two:

The present application proposes an embodiment of a low-temperature cabinet, as shown in Figures 3-5, which includes a box shell 910, and an accommodation space is formed inside the box shell 910. In order to achieve the thermal insulation performance of the low-temperature cabinet, in some embodiments, the The case shell 910 is also provided with an insulating layer correspondingly, through which the cold energy in the low-temperature cabinet can be prevented from leaking outward.

The present application also includes the self-cascading refrigeration system in Embodiment 1, which is assembled in the accommodating space, and the self-cascading refrigeration system arranged in the box shell 910 can be used for low-temperature refrigeration of the items stored inside the box shell 910, Realize the storage of low temperature items.

In some embodiments of the present application, a first partition part 920 is further provided inside the case shell 910, and the first partition part 920 divides the case case 910 to form a first chamber 911 and a second chamber 912, The first partition member 920 can be a partition plate, which is vertically arranged in the case 910, and the first chamber 911 and the second chamber 912 formed by dividing the first partition member 920 are arranged side by side.

In some embodiments of the present application, a second partition member 930 is further provided in the first chamber 911 , and the second partition member 930 divides the first chamber 911 into a compressor compartment 9111 and an equipment compartment 9112 .

The second partition member 930 can be selected as a second partition, which is arranged vertically to the first partition member 920 and the side wall of the first chamber 911, and is arranged horizontally to divide the first chamber 911. It can be welded or buckled. are fixedly connected to the first partition member 920 and the side wall of the first chamber 911 in the same manner.

The equipment compartment 9112 is disposed above the compressor compartment 9111 , and the expansion tank 400 is disposed in the equipment compartment 9112 .

Through the function of the second partition member 930, the expansion tank 400 can be assembled above the compressor chamber 9111. When the compressor 110 returns oil, the lubricating oil at the bottom of the expansion tank 400 can return to the compressor 110 more easily due to gravity internal.

In order to realize the fixed assembly of the expansion tank 400, in some embodiments of the present application, a clamping part 931 is provided on the second partition part 930, and the expansion tank 400 is clamped in the clamping part 931, which The interface part 410 faces the compressor compartment 9111 .

In some embodiments of the present application, the clamping portion 931 is a clamping slot opened on the second partition member 930 , the clamping slot is provided through the second partition member 930 , and the expansion tank 400 is clamped on the clamping slot.

The interface part 410 is exposed from the bottom of the slot so as to be connected and matched with the pressure relief channel 600 and the compressor suction channel 500 located in the compressor chamber 9111 .

In order to further fix the expansion tank 400 , in some embodiments, a clamping component 940 for clamping and fixing the expansion tank 400 is also provided, and the clamping component 940 is disposed on the second partition component 930 .

The clamping part 940 can directly use the clamping parts such as clamps in the prior art, as long as it can be used to clamp and fix the expansion tank 400, there is no specific limitation here, and it can be clamped correspondingly during assembly. The part 940 is assembled on the second partition part 930 .

The clamping component 930 can be configured as a structure adapted to the outer contour of the expansion tank 400 , so that it can be clamped relatively tightly on the outer surface of the expansion tank 400 .

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art can still understand the foregoing embodiments. Modifications are made to the technical solutions described, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions claimed in the present invention.

Claims (10)

1. A self-cascade refrigeration system comprising:

a self-cascade refrigeration loop: the system is formed by connecting a compressor, an oil separator, a condenser, a multi-stage gas-liquid separator, a multi-stage heat exchanger, a heat regenerator and an evaporator through a refrigerant liquid path and a refrigerant gas path;

an expansion tank connected with the refrigerant gas path for pressure relief of the system, which is characterized in that,

the bottom of the expansion tank is provided with a connecting part communicated with the internal space of the expansion tank, and the suction side of the compressor is connected with the connecting part through a suction channel of the compressor.

2. The self-cascade refrigeration system of claim 1, wherein the interface portion is a mouthpiece, and is inserted into a bottom position of the expansion tank, the expansion tank is connected to the refrigerant gas path through a pressure relief channel, and the pressure relief channel and a compressor suction channel are both communicated with the mouthpiece.

3. The self-laminating refrigeration system of claim 1, wherein the interface portion includes a first interface and a second interface, the first interface and the second interface each being disposed at a bottom of the expansion tank, the first interface being connected to the pressure relief passage, the second interface being connected to the compressor suction passage.

4. The self-cascade refrigeration system of any one of claims 1 to 3, wherein a throttling member for throttling depressurization is provided on the compressor suction passage.

5. The self-laminating refrigeration system of any one of claims 1-3, wherein the throttling element is a throttling capillary tube.

6. The self-stacking refrigeration system of claim 5, further comprising a filter element disposed on the compressor suction passage.

7. The self-cascade refrigeration system according to claim 1, wherein the refrigerant gas circuit comprises a refrigerant branch pipe configured with a plurality of stages of gas-liquid separators, the pressure relief channel is connected to the refrigerant gas pipe configured with one of the gas-liquid separators below the expansion tank and the primary gas-liquid separator, and a control component for controlling the on-off of the pressure relief channel is arranged on the pressure relief channel.

8. A cryogenic cabinet comprising a cabinet enclosure, further comprising a self-cascade refrigeration system of any one of claims 1-7 and:

a first partition member disposed within the enclosure to divide the enclosure into a first chamber and a second chamber;

and the second partition part is arranged in the first cavity and divides the first cavity into a compressor bin and an equipment bin, the equipment bin is arranged above the compressor bin, and the expansion tank is arranged in the equipment bin.

9. The cryogenic cabinet of claim 8, wherein a snap-fit portion is provided on the second partition member, and the expansion tank is snap-fit within the snap-fit portion with an interface portion facing the compressor bin.

10. The cryogenic cabinet of claim 9 further comprising a clamping member for clamping and fixing the expansion tank, wherein the clamping member is disposed on the second partition member.

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