CN215260625U - Ultra-low temperature cascade refrigerating unit - Google Patents

Abstract

The utility model belongs to the technical field of refrigeration, especially, relate to an ultra-low temperature cascade refrigeration unit, including the liquid inlet pipe, the admission line, the condensation evaporimeter, low temperature level refrigeration subassembly and high temperature level refrigeration subassembly, at first provide the gaseous state refrigerant after preheating the subcooling to the condensation portion of condensation evaporimeter through the low temperature level refrigeration subassembly, then use through the cooperation of the evaporation department connection of high temperature level refrigeration subassembly with the condensation evaporimeter, it produces cold volume to evaporate the heat absorption in the evaporation portion of condensation evaporimeter, this cold volume supplies the condensation portion of condensation evaporimeter to make its interior refrigerant condensation, the rethread liquid outlet pipe gets into in customer's the evaporimeter evaporation and produces ultra-low temperature cold volume, the refrigerant after the evaporation gets back to the low temperature level refrigeration subassembly through the admission line and makes its circulation work; this application structure sets up rationally, mutually supports through two independent refrigerating system, not only improves refrigeration efficiency greatly, obtains super low temperature refrigeration effect, and the refrigerant can flow back to corresponding evaporimeter mesocycle work moreover, circulates, lasts the refrigeration.

Description

Ultra-low temperature cascade refrigerating unit

[ technical field ] A method for producing a semiconductor device

The utility model belongs to the technical field of the refrigeration, especially, relate to an ultra-low temperature cascade refrigeration unit.

[ background of the invention ]

With the development of society and the improvement of living standard, the low temperature requirement is more and more extensive. At present, the low temperature above minus 40 ℃ can be realized by conventional single-stage compression refrigeration, but the requirement of the temperature below minus 40 ℃ is more and more common, such as low-temperature biological preservation, sensor cooling, material and article testing under the low temperature condition, low-temperature medicine, space technology, oil and gas industry and the like, all need to be operated in the low-temperature environment below minus 40 ℃, and the overlapping refrigeration is a main realization means. However, in the actual development process of application technology, only if the high-low temperature cycle is properly matched, the cascade refrigeration system can exert the ultralow temperature refrigeration efficiency, so that the ultralow temperature refrigeration system can safely and reliably operate, and therefore an ultralow temperature cascade refrigeration unit with a reasonable structure is urgently needed.

[ Utility model ] content

The utility model aims to overcome the defects in the prior art, and provides an ultra-low temperature cascade refrigerating unit which has reasonable structure and can continuously and effectively provide the refrigerating effect.

The utility model discloses realized by following technical scheme:

the ultra-low temperature cascade refrigerating unit comprises a liquid outlet pipeline for guiding and delivering liquid refrigerant and an air inlet pipeline for receiving gaseous refrigerant; further comprising:

the condensation evaporator is provided with an evaporation part and a condensation part, and the condensation part is communicated with the liquid outlet pipeline;

the low-temperature-stage refrigeration assembly is communicated with the condensation part of the condensation evaporator and is used for providing gaseous refrigerants to the condensation part of the condensation evaporator;

and the high-temperature-stage refrigeration assembly is communicated with the evaporation part of the condensation evaporator and is used for providing cold energy for the gaseous refrigerant in the condensation part of the condensation evaporator so as to condense the gaseous refrigerant into a liquid refrigerant.

As described above, the ultra-low temperature cascade refrigerator set, the low temperature stage refrigerating module includes:

a low temperature stage compressor;

a low temperature stage oil separator in communication with the low temperature stage compressor;

one end of the precooling heat exchanger is communicated with the low-temperature-level oil separator, and the other end of the precooling heat exchanger is communicated with the condensing part of the condensing evaporator;

and one end of the low-temperature-stage gas separator is communicated with the low-temperature-stage compressor, and the other end of the low-temperature-stage gas separator is communicated with the gas inlet pipeline.

In the ultra-low temperature cascade refrigeration unit, the low-temperature-stage oil separator includes a first-stage oil separator communicated with the low-temperature-stage compressor, and a second-stage oil separator communicated with the first-stage oil separator and the precooling heat exchanger.

According to the ultra-low temperature cascade refrigeration unit, a low-temperature oil return pipeline communicated with the first-stage oil separator, the second-stage oil separator and the low-temperature compressor is arranged between the low-temperature oil separator and the low-temperature compressor, and a first-stage ball valve switch, a first-stage oil filter and a first-stage electromagnetic valve are sequentially arranged on the low-temperature oil return pipeline along the oil return direction.

As above ultra-low temperature overlapping formula refrigerating unit, the precooling heat exchanger includes first fin subassembly, wear to be equipped with a plurality of first sub-input tubes and first sub-output tube on the first fin subassembly, it is a plurality of first sub-input tube communicates jointly has first input tube overall, and is a plurality of first sub-output tube communicates jointly has first output tube overall, first input tube overall with second grade oil separator intercommunication, first output tube overall with condensation evaporator's condensation portion intercommunication.

As described above in the ultra-low temperature cascade refrigerator set, the high temperature stage refrigerating module includes:

a high temperature stage compressor;

a high temperature stage oil separator in communication with the high temperature stage compressor;

a condenser, one end of which is communicated with the high-temperature-stage oil separator, and the other end of which is communicated with an evaporation part of the condensation evaporator;

and one end of the high-temperature-stage gas separator is communicated with the evaporation part of the condensation evaporator, and the other end of the high-temperature-stage gas separator is communicated with the high-temperature-stage compressor.

As above ultra-low temperature cascade refrigeration unit, the condenser includes the second fin subassembly, wear to be equipped with a plurality of second sub input tubes and the sub output tube of second on the second fin subassembly, it is a plurality of the sub input tube of second communicates jointly has the total input tube of second, and is a plurality of the sub output tube of second communicates jointly has the total output tube of second, the total input tube of second with high temperature level oil separator intercommunication, the total output tube of second with the evaporation portion intercommunication of condensation evaporimeter.

According to the ultra-low temperature cascade refrigeration unit, the high-temperature oil separator is communicated with the high-temperature compressor through the high-temperature oil return pipeline, and the high-temperature oil return pipeline is sequentially provided with the second-stage ball valve switch, the second-stage oil filter and the second-stage electromagnetic valve along the oil return direction.

According to the ultra-low temperature cascade refrigeration unit, the precooling heat exchanger is arranged above the condenser, and the air cooling unit is arranged above the precooling heat exchanger.

The ultra-low temperature cascade refrigeration unit further comprises a unit box, wherein the liquid outlet pipeline, the air inlet pipeline, the condensation evaporator, the low-temperature refrigeration component and the high-temperature refrigeration component are all arranged in the unit box, a liquid outlet opening for communicating the outside and the liquid outlet pipeline and an air inlet opening for communicating the outside and the air inlet pipeline are further arranged on the side wall of the box body of the unit box, and the air cooling unit is arranged at the top of the unit box; and a plurality of radiating hole groups are arranged on the side wall of the box body of the unit box, and correspond to the precooling heat exchanger and the condenser.

Compared with the prior art, the utility model discloses there is following advantage:

1. the utility model provides an ultra-low temperature cascade refrigerating unit, including the liquid outlet pipeline that is used for leading and sending the liquid refrigerant and the admission line that is used for receiving the gaseous state refrigerant, during the use, connect liquid outlet pipeline and admission line and customer's evaporimeter installation, provide the gaseous state refrigerant after preheating the subcooling to the condensation portion of condensation evaporimeter through low temperature level refrigeration subassembly at first, then connect the cooperation with the evaporation department of condensation evaporimeter through high temperature level refrigeration subassembly and use, make the refrigerant form refrigeration cycle system between high temperature level refrigeration subassembly and condensation evaporimeter, evaporate the heat absorption at the evaporation department of condensation evaporimeter and produce cold volume, and the cold volume that produces supplies to the condensation portion of condensation evaporimeter so that the gaseous state refrigerant after preheating the subcooling in it condenses into the liquid refrigerant, the liquid refrigerant rethread liquid outlet pipeline gets into in customer's evaporimeter and evaporates and produces the ultra-low temperature cold volume, the evaporated refrigerant returns to the low-temperature stage refrigeration assembly through the air inlet pipeline to circularly work; the refrigeration system is reasonable in structural arrangement, and through mutual matching of the two independent refrigeration systems, the refrigeration efficiency is greatly improved, the ultralow-temperature refrigeration effect is obtained, the refrigerant can flow back to the corresponding evaporator to circularly work, and can be circularly and continuously refrigerated, so that the energy-saving purpose is achieved, the practical application requirements are met, and further development of the refrigeration industry is facilitated;

2. the air cooling unit is adopted, and the cooling fins are matched with the fan arranged at the top of the unit box for cooling, so that a special machine room is not required to be occupied, a cooling tower and a pump room are not required to be installed, the operation is convenient, and the maintenance of professional personnel is not required; the air-cooled machine set has no cooling water system, so that the urban water is saved; and the maintenance cost is lower than that of a water chilling unit;

3. this application locates the unit incasement with condensation evaporator, low temperature level refrigeration subassembly and high temperature level refrigeration subassembly, only needs to be connected liquid outlet pipe and admission line and customer end evaporimeter when using, can circulate and obtain ultra-low temperature cold volume effectively, and is simple to use, and the transportation is convenient.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below.

Fig. 1 is a perspective view of the present invention;

fig. 2 is a schematic structural view of the inside of the ultra-low temperature cascade refrigeration unit of the present invention;

fig. 3 is a schematic structural view of the inside of the ultra-low temperature cascade refrigeration unit of the present invention;

fig. 4 is a sectional view taken along the line a-a in fig. 1.

[ detailed description ] embodiments

In order to make the technical problem, technical solution and advantageous effects solved by the present invention more clearly understood, the following description is given in conjunction with the accompanying drawings and embodiments to further explain the present invention in detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

When embodiments of the present invention refer to the ordinal numbers "first", "second", etc., it should be understood that the terms are used for distinguishing only when they do express the ordinal order in context.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In a specific embodiment, the ultra-low temperature cascade refrigeration unit shown in fig. 1 to 4 includes a liquid outlet pipeline 1 for guiding and sending a liquid refrigerant and an air inlet pipeline 2 for receiving a gaseous refrigerant; further comprising: the condensation evaporator 3 is provided with an evaporation part and a condensation part, and the condensation part is communicated with the liquid outlet pipeline 1; the low-temperature-stage refrigeration assembly 4 is communicated with the condensation part of the condensation evaporator 3 and is used for providing gaseous refrigerants for the condensation part of the condensation evaporator 3; and the high-temperature-stage refrigeration assembly 5 is communicated with the evaporation part of the condensation evaporator 3 and is used for providing cold energy for the gaseous refrigerant in the condensation part of the condensation evaporator 3 so as to condense the gaseous refrigerant into a liquid refrigerant. When the refrigeration system is used, the liquid outlet pipeline and the air inlet pipeline are connected and installed with an evaporator of a client, firstly, a low-temperature stage refrigeration assembly provides preheated and supercooled gaseous refrigerant to a condensation part of a condensation evaporator, then, the high-temperature stage refrigeration assembly is connected and matched with an evaporation part of the condensation evaporator for use, so that the refrigerant forms a refrigeration cycle system between the high-temperature stage refrigeration assembly and the condensation evaporator, the evaporation part of the condensation evaporator evaporates and absorbs heat to generate cold energy, the generated cold energy is supplied to the condensation part of the condensation evaporator to condense the preheated and supercooled gaseous refrigerant in the condensation evaporator into liquid refrigerant, the liquid refrigerant enters the evaporator of the client through the liquid outlet pipeline to be evaporated to generate ultralow-temperature cold energy, the ultralow temperature can reach-65 ℃, and the evaporated refrigerant returns to the low-temperature stage refrigeration assembly through the air inlet pipeline to enable the low-temperature stage refrigeration assembly to work in a cycle mode; this application structure sets up rationally, mutually supports through two independent refrigerating system, not only improves refrigeration efficiency greatly, obtains super low temperature refrigeration effect, and the refrigerant can flow back to corresponding evaporimeter mesocycle work moreover, and circulation, continuous refrigeration have reached energy-conserving purpose, satisfy in the actual application demand of reality, and then are favorable to the further development of refrigeration trade.

In particular, the low-temperature stage refrigeration assembly 4 comprises: a low-temperature stage compressor 41; a low temperature stage oil separator 42 in communication with the low temperature stage compressor 41; a pre-cooling heat exchanger 43, one end of which is communicated with the low-temperature-stage oil separator 42, and the other end of which is communicated with the condensation part of the condensation evaporator 3; and a low-temperature-stage gas separator 44, one end of which is communicated with the low-temperature-stage compressor 41, and the other end of which is communicated with the gas inlet pipeline 2. When the refrigeration device is used, lubricating oil is added into the low-temperature stage compressor 41, the refrigerant is compressed by the low-temperature stage compressor 41, enters the low-temperature stage oil separator 42 to separate the lubricating oil, enters the precooling heat exchanger for precooling heat exchange, enters the condensing part of the condensing evaporator 3 to be condensed into liquid refrigerant, the liquid refrigerant is directly supplied to the evaporator of a client through the liquid outlet pipeline 1, the ultralow-temperature cold energy is evaporated in the evaporator of the client, the evaporated gaseous refrigerant passes through the air inlet pipeline 2, passes through the low-temperature stage gas separator 44 and then returns to the low-temperature stage compressor 41 for compression, the ultralow-temperature cold energy is obtained accordingly, the circulating refrigeration is realized, and the structure is reasonable.

In addition, the low-temperature stage oil separator 42 includes a first-stage oil separator 421 communicating with the low-temperature stage compressor 41, and a second-stage oil separator 422 communicating with the first-stage oil separator 421 and the pre-cooling heat exchanger 43. The first-stage oil separator 421 is a high-efficiency oil separator, the second-stage oil separator 422 is a common oil separator, and the two oil separators enable the lubricating oil separation efficiency to be higher and facilitate subsequent refrigeration work.

Further, a low-temperature oil return pipeline 6 communicating the first-stage oil separator 421, the second-stage oil separator 422 and the low-temperature compressor 41 is arranged between the low-temperature oil separator 42 and the low-temperature compressor 41, and a first-stage ball valve switch 61, a first-stage oil filter 62 and a first-stage electromagnetic valve 63 are sequentially arranged on the low-temperature oil return pipeline 6 along an oil return direction. Lubricating oil separated from the first-stage oil separator 421 and the second-stage oil separator 422 is reserved in the low-temperature-stage compressor 41 through the low-temperature-stage oil return pipeline 6 for use in compression, so that the effect of recycling the lubricating oil is achieved, the environment is protected, and the cost is reduced.

More specifically, the precooling heat exchanger 43 includes a first fin assembly 431, a plurality of first sub input pipes 432 and first sub output pipes 433 are arranged on the first fin assembly 431 in a penetrating manner, a plurality of first sub input pipes 432 are communicated with a first total input pipe 434, a plurality of first sub output pipes 433 are communicated with a first total output pipe 435, the first total input pipe 434 is communicated with the secondary oil separator 422, and the first total output pipe 435 is communicated with the condensation portion of the condensation evaporator 3. The refrigerant compressed by the low-temperature stage compressor 41 and separated from the lubricating oil by the low-temperature stage oil separator 42 enters each first sub-input pipe 432 from the first main input pipe 434, is pre-cooled and superheated by the first fin assembly 431, is output from the first sub-output pipe 433 and collected to the first main output pipe 435, is conveyed to the condensation part of the condensation evaporator 3 through the first main output pipe 435 for condensation, and is cooled by adopting the first fin assembly 431, so that the cost is low, a cooling water system is not needed, and the urban water is saved.

Further, the high temperature stage refrigeration assembly 5 comprises: a high-temperature stage compressor 51; a high temperature stage oil separator 52 in communication with the high temperature stage compressor 51; a condenser 53 having one end communicating with the high-temperature-stage oil separator 52 and the other end communicating with the evaporation part of the condensation evaporator 3; and a high-temperature-stage separator 54 having one end communicating with the evaporation unit of the condensation evaporator 3 and the other end communicating with the high-temperature-stage compressor 51. When the refrigerant circulating refrigeration device is used, lubricating oil is added into the high-temperature-stage compressor 51, the refrigerant is compressed by the high-temperature-stage compressor 51, then enters the high-temperature-stage oil separator 52 to be separated out from the lubricating oil, then enters the condenser 53 to be condensed, and then enters the evaporation part of the condensation evaporator 3 to be evaporated and absorbed to generate cold energy for condensing the refrigerant in the condensation part of the condensation evaporator 3, and the evaporated gaseous refrigerant is subjected to liquid removal by the high-temperature-stage gas separator 54 and then enters the high-temperature-stage compressor 51 again to be compressed, so that circulating refrigeration is realized.

Still further, the condenser 53 includes a second fin assembly 531, a plurality of second sub input pipes 532 and second sub output pipes 533 are arranged on the second fin assembly 531 in a penetrating manner, a plurality of second sub input pipes 532 are commonly communicated with a second total input pipe 534, a plurality of second sub output pipes 533 are commonly communicated with a second total output pipe 535, the second total input pipe 534 is communicated with the high temperature stage oil separator 52, and the second total output pipe 535 is communicated with the evaporation portion of the condensation evaporator 3. The refrigerant compressed by the high-temperature stage compressor 51 and separated from the lubricating oil by the high-temperature stage oil separator 52 enters each of the second sub-input pipes 532 from the second main input pipe 534, is pre-cooled and superheated by the second fin assembly 531, is output from the second sub-output pipe 533 and collected to the second main output pipe 535, is conveyed to the evaporation part of the condensation evaporator 3 through the second main output pipe 535 to be evaporated, and provides cold energy for condensation in the condensation part of the condensation evaporator 3.

Specifically, a high-temperature-stage oil return pipeline 7 is communicated between the high-temperature-stage oil separator 52 and the high-temperature-stage compressor 51, and a second-stage ball valve switch 71, a second-stage oil filter 72 and a second-stage electromagnetic valve 73 are sequentially arranged on the high-temperature-stage oil return pipeline 7 along an oil return direction. Lubricating oil separated from the high-temperature-stage oil separator 52 is kept back to the high-temperature-stage compressor 51 through the high-temperature-stage oil return pipeline 7 for use during compression, so that the effect of recycling the lubricating oil is achieved, and the lubricating oil recycling device is more environment-friendly and reduces the cost.

More specifically, the pre-cooling heat exchanger 43 is disposed above the condenser 53, and an air-cooling unit 8 is disposed above the pre-cooling heat exchanger 43, where the air-cooling unit 8 includes a plurality of fans, preferably two fans. The cooling fins are matched with a fan arranged at the top of the unit box for cooling, so that a special machine room is not required to be occupied, a cooling tower and a pump room are not required to be installed, the operation is convenient, and the maintenance of professional personnel is not required; the air-cooled machine set has no cooling water system, so that the urban water is saved; and the maintenance cost is lower than that of a water chilling unit.

The air cooling unit 8 is arranged at the top of the unit box 9, when in use, the liquid outlet pipeline and the air inlet pipeline are only connected with a client evaporator, so that the ultralow-temperature cold energy can be circularly and effectively obtained, the use is simple, and the transportation is convenient; a plurality of radiating hole groups 91 are arranged on the side wall of the box body of the unit box 9, and the radiating hole groups 91 correspond to the precooling heat exchanger 43 and the condenser 53, so that heat dissipation is facilitated.

When the ultra-low temperature cascade refrigerating unit of the utility model is used, the liquid outlet pipeline and the air inlet pipeline are connected and installed with the evaporator of a client, firstly, the gaseous refrigerant after preheating and supercooling is provided for the condensing part of the condensing evaporator through the low temperature level refrigerating assembly, then the high-temperature stage refrigeration component is connected and matched with an evaporation part of the condensation evaporator for use, so that the refrigerant forms a refrigeration cycle system between the high-temperature stage refrigeration component and the condensation evaporator, the cold energy is generated by evaporating and absorbing heat in an evaporation part of the condensation evaporator, the generated cold energy is supplied to a condensation part of the condensation evaporator so that the gaseous refrigerant preheated and supercooled in the condensation evaporator is condensed into liquid refrigerant, the liquid refrigerant enters an evaporator of a client through a liquid outlet pipeline to be evaporated to generate ultralow temperature cold energy which can reach the ultralow temperature of-65 ℃, and the evaporated refrigerant returns to a low-temperature stage refrigeration assembly through an air inlet pipeline to enable the low-temperature stage refrigeration assembly to work circularly; the refrigeration system is reasonable in structural arrangement, and through mutual matching of the two independent refrigeration systems, the refrigeration efficiency is greatly improved, the ultralow-temperature refrigeration effect is obtained, the refrigerant can flow back to the corresponding evaporator to circularly work, and can be circularly and continuously refrigerated, so that the energy-saving purpose is achieved, the practical application requirements are met, and further development of the refrigeration industry is facilitated; the cooling fins are matched with a fan arranged at the top of the unit box for cooling, so that a special machine room is not required to be occupied, a cooling tower and a pump room are not required to be installed, the operation is convenient, and the maintenance of professional personnel is not required; the air-cooled machine set has no cooling water system, so that the urban water is saved; and the maintenance cost is lower than that of a water chilling unit; this application locates the unit incasement with condensation evaporator, low temperature level refrigeration subassembly and high temperature level refrigeration subassembly, only needs to be connected liquid outlet pipe and admission line and customer end evaporimeter when using, can circulate and obtain ultra-low temperature cold volume effectively, and is simple to use, and the transportation is convenient.

The above description is provided for one embodiment of the present invention, and the embodiments of the present invention are not limited to these descriptions, and the present invention is not limited to the above nomenclature and the English nomenclature since the trade nomenclature is different. All with the utility model discloses a method, structure etc. are similar, the same, or to the utility model discloses make a plurality of technological deductions or replacement under the design prerequisite, all should regard as the utility model discloses a protection scope.

Claims (10)

1. The ultra-low temperature cascade refrigerating unit is characterized by comprising a liquid outlet pipeline (1) for guiding and conveying liquid refrigerant and an air inlet pipeline (2) for receiving gaseous refrigerant; further comprising:

the condensation evaporator (3) is provided with an evaporation part and a condensation part, and the condensation part is communicated with the liquid outlet pipeline (1);

the low-temperature-stage refrigeration assembly (4) is communicated with the condensation part of the condensation evaporator (3) and is used for providing gaseous refrigerants for the condensation part of the condensation evaporator (3);

and the high-temperature-stage refrigeration assembly (5) is communicated with the evaporation part of the condensation evaporator (3) and is used for providing cold energy for the gaseous refrigerant in the condensation part of the condensation evaporator (3) so as to condense the gaseous refrigerant into a liquid refrigerant.

2. The ultra-low temperature cascade refrigeration unit of claim 1, wherein the low temperature stage refrigeration assembly (4) comprises:

a low-temperature stage compressor (41);

a low temperature stage oil separator (42) in communication with the low temperature stage compressor (41);

a precooling heat exchanger (43), one end of which is communicated with the low-temperature-stage oil separator (42), and the other end of which is communicated with a condensing part of the condensing evaporator (3);

and one end of the low-temperature-stage gas separator (44) is communicated with the low-temperature-stage compressor (41), and the other end of the low-temperature-stage gas separator is communicated with the gas inlet pipeline (2).

3. The ultra-low temperature cascade refrigeration unit of claim 2, wherein the low temperature stage oil separator (42) comprises a first stage oil separator (421) in communication with the low temperature stage compressor (41), and a second stage oil separator (422) in communication with the first stage oil separator (421) and a pre-cooling heat exchanger (43).

4. The ultra-low temperature overlapping type refrigerating unit according to claim 3, wherein a low temperature stage oil return pipeline (6) communicated with the first stage oil separator (421), the second stage oil separator (422) and the low temperature stage compressor (41) is arranged between the low temperature stage oil separator (42) and the low temperature stage compressor (41), and a first stage ball valve switch (61), a first stage oil filter (62) and a first stage electromagnetic valve (63) are sequentially arranged on the low temperature stage oil return pipeline (6) along an oil return direction.

5. The ultra-low temperature cascade refrigerating unit according to claim 3, wherein the pre-cooling heat exchanger (43) comprises a first fin assembly (431), a plurality of first sub-input pipes (432) and first sub-output pipes (433) are arranged on the first fin assembly (431) in a penetrating manner, a plurality of first sub-input pipes (432) are communicated with a first total input pipe (434) in common, a plurality of first sub-output pipes (433) are communicated with a first total output pipe (435) in common, the first total input pipe (434) is communicated with the secondary oil separator (422), and the first total output pipe (435) is communicated with a condensing portion of the condensing evaporator (3).

6. The ultra-low temperature cascade refrigeration unit of claim 3, wherein the high temperature stage refrigeration assembly (5) comprises:

a high-temperature stage compressor (51);

a high temperature stage oil separator (52) in communication with the high temperature stage compressor (51);

a condenser (53) having one end communicating with the high-temperature-stage oil separator (52) and the other end communicating with an evaporation part of the condensation evaporator (3);

and one end of the high-temperature-stage gas separator (54) is communicated with the evaporation part of the condensation evaporator (3), and the other end of the high-temperature-stage gas separator is communicated with the high-temperature-stage compressor (51).

7. The ultra-low temperature cascade refrigerator set according to claim 6, wherein the condenser (53) comprises a second fin assembly (531), the second fin assembly (531) is provided with a plurality of second sub-input pipes (532) and second sub-output pipes (533) in a penetrating manner, the plurality of second sub-input pipes (532) are commonly communicated with a second main input pipe (534), the plurality of second sub-output pipes (533) are commonly communicated with a second main output pipe (535), the second main input pipe (534) is communicated with the high temperature stage oil separator (52), and the second main output pipe (535) is communicated with the evaporation part of the condensing evaporator (3).

8. The ultra-low temperature overlapping type refrigerating unit according to claim 6, wherein a high temperature oil return pipeline (7) is communicated between the high temperature oil separator (52) and the high temperature compressor (51), and a second ball valve switch (71), a second oil filter (72) and a second electromagnetic valve (73) are sequentially arranged on the high temperature oil return pipeline (7) along an oil return direction.

9. The ultra-low temperature cascade refrigeration unit according to claim 6, wherein the pre-cooling heat exchanger (43) is disposed above the condenser (53), and the air-cooling unit (8) is disposed above the pre-cooling heat exchanger (43).

10. The ultra-low temperature cascade refrigeration unit according to claim 9, further comprising a unit box (9), wherein the liquid outlet pipe (1), the air inlet pipe (2), the condenser-evaporator (3), the low temperature stage refrigeration component (4), and the high temperature stage refrigeration component (5) are all disposed in the unit box (9), a liquid outlet opening (92) for communicating the outside with the liquid outlet pipe (1) and an air inlet opening (93) for communicating the outside with the air inlet pipe (2) are further disposed on a side wall of the unit box (9), and the air cooling unit (8) is disposed at the top of the unit box (9); the side wall of the box body of the unit box (9) is provided with a plurality of radiating hole groups (91), and the radiating hole groups (91) correspond to the precooling heat exchanger (43) and the condenser (53).

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