阅读说明：本技术 一种基于冷凝热量对箱体横梁除霜的超低温冰箱 (Ultra-low temperature refrigerator based on condensation heat is to defrosting of box crossbeam ) 是由 刘发柱 孙晓雪 于 2020-04-29 设计创作，主要内容包括：本发明提供一种基于冷凝热量对箱体横梁除霜的超低温冰箱,其高温级压缩制冷循环结构具有除霜支路,所述除霜支路上设置有高温级压缩机、冷凝器、第一框体管、第二框体管以及第三框体管,所述第二框体管设置在箱体横梁处,高温级冷凝器排出的高温级制冷剂流经所述除霜支路的第一框体管、第二框体管以及第三框体管,最终回流至高温级压缩机进行循环。本发明通过结合制冷系统的基本原理,将高温级的部分冷凝热量用来给箱体横梁处箱体管除霜。如此,既可以不增加整台冰箱的成本,又保持整台冰箱原有结构,避免了结构设计及工艺加工改进。使得超低温冰箱的性能得到了保障,延长了整机的使用寿命。(The invention provides an ultra-low temperature refrigerator for defrosting a box body cross beam based on condensation heat, wherein a high-temperature stage compression refrigeration cycle structure of the ultra-low temperature refrigerator is provided with a defrosting branch, a high-temperature stage compressor, a condenser, a first frame body pipe, a second frame body pipe and a third frame body pipe are arranged on the defrosting branch, the second frame body pipe is arranged at the box body cross beam, and a high-temperature stage refrigerant discharged by the high-temperature stage condenser flows through the first frame body pipe, the second frame body pipe and the third frame body pipe of the defrosting branch and finally flows back to the high-temperature stage compressor for circulation. The invention combines the basic principle of a refrigeration system to use partial condensation heat of a high-temperature stage to defrost a box body pipe at a box body cross beam. Therefore, the cost of the whole refrigerator is not increased, the original structure of the whole refrigerator is kept, and structural design and process processing improvement are avoided. The performance of the ultra-low temperature refrigerator is guaranteed, and the service life of the whole refrigerator is prolonged.)

1. An ultra-low temperature refrigerator for defrosting a box body beam based on condensation heat comprises a high-temperature stage compression refrigeration cycle structure and a low-temperature stage compression refrigeration cycle structure which work simultaneously, and is characterized in that,

the high-temperature stage compression refrigeration cycle structure is provided with a defrosting branch, a high-temperature stage compressor, a condenser, a first frame pipe, a second frame pipe and a third frame pipe are arranged on the defrosting branch, the second frame pipe is arranged at a box body cross beam, and a high-temperature stage refrigerant discharged by the high-temperature stage compressor is cooled by the condenser; wherein

One end of the first frame pipe is connected with a high-temperature-level refrigerant outlet of the condenser, and the other end of the first frame pipe is connected with the second frame pipe; the other end of the second frame pipe is connected with the third frame pipe; the other end of the third frame pipe is connected with a refrigerant recovery port of the high-temperature stage compressor;

when the defrosting branch circuit works, high-temperature-level refrigerant discharged by the condenser flows through the first frame pipe, the second frame pipe and the third frame pipe of the defrosting branch circuit, and finally flows back to the high-temperature-level compressor for circulation.

2. The ultra-low temperature refrigerator for defrosting cabinet beams based on condensation heat according to claim 1, wherein the defrosting branch further has a fourth frame pipe;

one end of the first frame body pipe is respectively connected with the second frame body pipe and the fourth frame body pipe through a three-way device; the other end of the fourth frame pipe is connected with the second frame pipe and the third frame pipe through a three-way device respectively.

3. The ultra-low temperature refrigerator for defrosting a box body cross beam based on condensation heat according to claim 1 or 2, wherein the high temperature stage compression refrigeration cycle structure is further provided with a high temperature stage refrigeration cycle branch, and a high temperature stage compressor, a condenser, a high temperature stage drying filter, a high temperature stage capillary tube and a condensation evaporator are arranged on the high temperature stage refrigeration cycle branch;

and a high-temperature-stage refrigerant discharged by the high-temperature-stage compressor is treated by the condenser and then sent to the low-temperature-stage compressor for heat exchange, then sequentially passes through the high-temperature-stage drying filter and the high-temperature-stage capillary tube, then is sent to the condensation evaporator for evaporation, and finally flows back to the high-temperature-stage compressor for circulation.

4. The ultra-low temperature refrigerator for defrosting a cross member of a cabinet based on condensation heat of claim 1, wherein the high temperature stage refrigerant is an intermediate temperature refrigerant.

5. The ultra-low temperature refrigerator for defrosting a cross beam of a box body based on condensation heat according to claim 3, wherein the low temperature stage compression refrigeration cycle structure comprises a low temperature stage compressor, an oil separator, a condensation evaporator, a low temperature stage drying filter, a low temperature stage capillary tube and an evaporator;

the low-temperature stage refrigerant discharged by the low-temperature stage compressor firstly passes through the oil separator, flows back the filtered oil to the low-temperature stage compressor, flows to the condensing evaporator, is cooled into liquid after exchanging heat with the high-temperature stage refrigerant, sequentially passes through the low-temperature stage drying filter and the low-temperature stage capillary tube, enters the evaporator for evaporation and refrigeration, and finally flows back to the low-temperature stage compressor for circulation.

6. The ultra-low temperature refrigerator for defrosting a cabinet beam based on condensation heat of claim 5, wherein the low temperature stage refrigerant is a low temperature refrigerant.

7. The ultra-low-temperature refrigerator for defrosting a cross member of a box body based on condensation heat according to claim 5, wherein the low-temperature stage compression refrigeration cycle structure further comprises an expansion tank connected between the evaporator and the low-temperature stage compressor through a capillary tube provided at a front end thereof.

Technical Field

The invention relates to a biomedical articles storage device, in particular to an ultra-low temperature refrigerator for defrosting a box body cross beam based on condensation heat.

Background

The medical refrigerator used in the biomedical field is a professional refrigerator for storing special medicines, and is mainly used for placing and storing medicines, vaccines, enzymes, hormones, stem cells, platelets, semen, transplanted skin, tissue samples of animals, extracted RNA, gene libraries, some important biological and chemical reagents and the like. With the development of scientific technology, medical refrigerators have become one of the important products in the field of biomedical science.

The medical refrigerator that present bio-medical field used can divide into multiple medical refrigerator according to the difference of temperature in the cabinet and service environment:

and (4) an environmental test chamber. When the temperature in the cabinet is 2-23 ℃, the large-volume environmental test chamber is used for special environmental chromatography tests by colleges and scientific research units. When the temperature in the cabinet is-10 ℃ to 60 ℃, the temperature-adjustable water tank is used for matching with high and low temperature tests.

Low noise medical refrigerator. The temperature in the cabinet is 2-8 ℃, and the device is used for sample preservation in institutions such as blood stations, hospital operating rooms and the like.

Medical low temperature preservation case. The temperature in the cabinet is-20 to-40 ℃, and the VIP heat insulation material is adopted, so that the energy-saving effect is achieved, and the VIP heat insulation material is used for storing fresh frozen plasma, vaccines, enzymes for genetic research, culture media, reagents and the like.

Medical hypothermia box. The temperature in the cabinet is-60 ℃, and the self-cascade single refrigeration system is applied, and the HC refrigerant is adopted, so that the energy is saved and the environment is protected. The temperature in the medical ultra-low temperature storage cabinet is-50 ℃ to-86 ℃, and can even reach-90 ℃. The system of the medical ultra-low temperature storage box is provided with a double refrigeration system, a VIP vacuum thermal baffle is used, the double systems operate simultaneously, when one system fails, the other single system can also operate normally, the temperature in the box is ensured to be below 70 ℃ below zero, and the refrigerator of the type is widely applied to low temperature storage of medical and scientific research units.

Large gaseous liquid nitrogen tanks. The temperature in the cabinet is-180 ℃ (gas phase), -196 ℃ (liquid phase), -180 ℃ -196 ℃ large-scale gas phase liquid nitrogen tank for storing sample bank, umbilical cord blood bank, cell tissue bank and the like at deep low temperature.

The temperature in the existing medical ultra-low temperature storage box and medical low temperature cabinet is generally below-50 ℃, and the refrigeration system is usually applied to a cascade system or a self-cascade system to obtain the ultra-low temperature environment. When a user uses the medical ultra-low temperature preservation box to open the door and take articles, the phenomenon of frosting and dewing can occur on the box body cross beam of the refrigerator. Along with the accumulation of time, if the frost can not be cleared up in time, the door body can not be closed tightly, and the problems of cold leakage and the like can be caused. In order to solve the problem, some technicians adopt a scheme of canceling a beam structure, but the method can cause the stability of the whole foaming door body to be reduced, and potential safety hazards exist. The method of using the additional defrosting device results in a great increase in cost. In order to solve the problem, the cost cannot be greatly increased, and the refrigerating performance and the structural stability of the whole refrigerator are not affected, a solution applying a refrigerating principle is designed.

Disclosure of Invention

According to the problems that when the existing ultra-low temperature refrigerator is opened to take objects, the refrigerator body beam is frosted and dewed, and the refrigerator outer door cannot be tightly closed and leaks cold and the like due to accumulation of the refrigerator outer door along with time, the invention provides a condensation heat-based ultra-low temperature refrigerator defrosting device which is mainly used for defrosting by utilizing the condensation heat according to a refrigeration principle.

The technical means adopted by the invention are as follows:

an ultra-low temperature refrigerator capable of defrosting a box body cross beam based on condensation heat comprises a high-temperature-stage compression refrigeration cycle structure and a low-temperature-stage compression refrigeration cycle structure, wherein the high-temperature-stage compression refrigeration cycle structure and the low-temperature-stage compression refrigeration cycle structure work simultaneously, the high-temperature-stage compression refrigeration cycle structure is provided with a defrosting branch, a high-temperature-stage compressor, a condenser, a first frame pipe, a second frame pipe and a third frame pipe are arranged on the defrosting branch, the second frame pipe is arranged at the box body cross beam, and a high-temperature-stage refrigerant discharged by the high-temperature-stage compressor is cooled by the condenser, wherein one end of the first frame pipe is connected with a high-temperature-stage refrigerant; the other end of the second frame pipe is connected with the third frame pipe; the other end of the third frame pipe is connected with a refrigerant recovery port of the high-temperature stage compressor; when the defrosting branch circuit works, high-temperature-stage refrigerant discharged by the high-temperature-stage condenser flows through the first frame pipe, the second frame pipe and the third frame pipe of the defrosting branch circuit and finally flows back to the high-temperature-stage compressor for circulation.

Further, the defrosting branch also has a fourth frame pipe; one end of the first frame body pipe is respectively connected with the second frame body pipe and the fourth frame body pipe through a three-way device; the other end of the fourth frame pipe is connected with the second frame pipe and the third frame pipe through a three-way device respectively.

Furthermore, the high-temperature stage compression refrigeration cycle structure is also provided with a high-temperature stage refrigeration cycle branch, and a high-temperature stage compressor, a condenser, a high-temperature stage drying filter, a high-temperature stage capillary tube and a condensation evaporator are arranged on the high-temperature stage refrigeration cycle branch; and a high-temperature-stage refrigerant discharged by the high-temperature-stage compressor is treated by the condenser and then sent to the low-temperature-stage compressor for heat exchange, then sequentially passes through the high-temperature-stage drying filter and the high-temperature-stage capillary tube, then is sent to the condensation evaporator for evaporation, and finally flows back to the high-temperature-stage compressor for circulation.

Further, the high-temperature stage refrigerant is an intermediate-temperature refrigerant.

Further, the low-temperature stage compression refrigeration cycle structure comprises a low-temperature stage compressor, an oil separator, a condensation evaporator, a low-temperature stage drying filter, a low-temperature stage capillary tube and an evaporator; the low-temperature stage refrigerant discharged by the low-temperature stage compressor firstly passes through the oil separator, flows back the filtered oil to the low-temperature stage compressor, flows to the condensation evaporator, is cooled into liquid after exchanging heat with the high-temperature stage refrigerant, sequentially passes through the low-temperature stage drying filter and the low-temperature stage capillary tube, enters the evaporator for evaporation and refrigeration, and finally flows back to the low-temperature stage compressor for circulation.

Further, the low-temperature stage refrigerant is a low-temperature refrigerant.

Further, the low-temperature stage compression refrigeration cycle structure further comprises an expansion tank, and the expansion tank is connected between the evaporator and the low-temperature stage compressor through a capillary tube arranged at the front end of the expansion tank.

Compared with the prior art, the invention has the following advantages:

1. the invention combines the basic principle of a refrigeration system, uses a part of condensation heat in the high-temperature stage compression refrigeration cycle to defrost a box body pipe at the box body beam, and solves the problem that the box door cannot be closed due to frosting and dewing.

2. The conventional ultra-low temperature refrigerator system is usually complex, the invention utilizes the principle of a refrigerating system, does not increase the cost of the whole refrigerator, ensures that the structure of the whole refrigerator is not changed, and avoids structural design and process processing improvement.

3. The invention ensures the performance of the ultra-low temperature refrigerator and prolongs the service life of the whole machine.

For the above reasons, the present invention can be widely applied to an ultra-low temperature refrigerator system.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic view of a defrosting branch of an ultra-low temperature refrigerator according to the present invention.

Fig. 2 is a schematic view of the compression refrigeration cycle of the ultra-low temperature refrigerator according to the present invention.

Fig. 3 is a schematic view showing the arrangement of second frame tubes of the ultra-low temperature refrigerator in the embodiment.

Fig. 4 is a schematic view of the piping arrangement of the evaporator of the ultra-low temperature refrigerator in the embodiment.

Fig. 5 is a schematic view of an external structure of an ultra-low temperature refrigerator in an embodiment.

In the figure: 10. a first frame pipe; 20. a second frame pipe; 30. a third frame pipe; 40. a fourth frame pipe; 51. a high temperature stage compressor; 52. a frame body pipe group; 53. a high temperature stage filter drier; 54. a high temperature stage capillary; 61. a low temperature stage compressor; 62. an oil separator 63, a low-temperature stage dry filter; 64. a low temperature stage capillary; 65. an evaporator; 66. an expansion tank capillary tube; 67. an expansion tank; 70. a condenser; 80. a condensing evaporator; 101. a refrigeration unit; 102. a refrigerator body; 103. an upper box body of the refrigerator; 104. a lower box body of the refrigerator; 105. a rack; 106. a box body cross beam; 107. an upper door of the refrigerator; 108. a lower door of the refrigerator; 109. and an outer door of the refrigerator.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. Any specific values in all examples shown and discussed herein are to be construed as exemplary only and not as limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the absence of any contrary indication, these directional terms are not intended to indicate and imply that the device or element so referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be considered as limiting the scope of the present invention: the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

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

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

The invention provides an ultra-low temperature refrigerator for defrosting a box body cross beam based on condensation heat, which applies a cascade compression refrigeration cycle, namely, the ultra-low temperature refrigerator comprises a high-temperature stage compression refrigeration cycle structure and a low-temperature stage compression refrigeration cycle structure, and the high-temperature stage compression refrigeration cycle structure and the low-temperature stage compression refrigeration cycle structure work simultaneously. Wherein the high-temperature-level refrigerant is a medium-temperature refrigerant, and the low-temperature-level refrigerant is a low-temperature refrigerant, so that two single-stage compression refrigeration cycles are formed. As shown in fig. 5, the external structure of the ultra-low temperature refrigerator of the present invention is schematically illustrated, and includes a refrigerator set 101, a refrigerator body 102, an upper refrigerator body 103, a lower refrigerator body 104, a shelf 105, a body beam 106, an upper refrigerator door (inner) 107, a lower refrigerator door (inner) 108, an outer refrigerator door 109, a frame tube structure, and an evaporator tube assembly.

The invention aims to solve the problems that when the existing ultra-low temperature refrigerator is opened to take articles, the refrigerator body cross beam of the refrigerator has the phenomenon of frosting and dewing, and the refrigerator outer door body cannot be tightly closed and leaks cold due to the accumulation of time and untimely cleaning.

Therefore, the present invention provides a defrosting branch in a high-temperature stage compression refrigeration cycle structure, as shown in fig. 1-2, a high-temperature stage compressor 51, a condenser 70, a first frame pipe 10, a second frame pipe 20, and a third frame pipe 30 are provided on the defrosting branch, and the second frame pipe 20 is provided at a tank cross beam, as shown in fig. 3. In operation, the high-temperature-stage compressor 51 discharges a high-temperature-stage refrigerant that is cooled by the condenser 70. One end of the first frame pipe 10 is connected with a high-temperature-level refrigerant outlet of the condenser 70, and the other end is connected with the second frame pipe 20; the other end of the second frame pipe 20 is connected with the third frame pipe 30; the other end of the third frame pipe 30 is connected with a refrigerant recovery port of a high-temperature stage compressor 51; in operation, the high-temperature-stage refrigerant discharged from the condenser flows through the first, second, and third casing pipes 10, 20, and 30 of the defrosting branch, and finally flows back to the high-temperature-stage compressor 51 to circulate.

In an embodiment of the present invention, the defrosting branch further has a fourth frame pipe, and one end of the first frame pipe 10 is connected to the second frame pipe 20 and the fourth frame pipe 40 through a three-way device; the other end of the fourth frame pipe 40 is connected to the second frame pipe 20 and the third frame pipe 30 through a tee joint device. Further, the high-temperature stage compression refrigeration cycle structure is also provided with a high-temperature stage refrigeration cycle branch, and the high-temperature stage refrigeration cycle branch is provided with a high-temperature stage compressor 51, a condenser 70, a high-temperature stage drying filter 53, a high-temperature stage capillary tube 54 and a condensation evaporator 80; the high-temperature-stage refrigerant discharged from the high-temperature-stage compressor 51 is cooled by the condenser 70, then sent to the low-temperature-stage compressor 61, cooled by the low-temperature-stage compressor 61, returned to the condenser 70 for cooling, then sequentially passed through the high-temperature-stage drying filter 53 and the high-temperature-stage capillary tube 54, sent to the condensing evaporator 80 for evaporation, and finally returned to the high-temperature-stage compressor 51 for circulation.

Specifically, when the ultra-low temperature refrigerator starts to work, the high temperature stage compression refrigeration cycle and the low temperature stage compression refrigeration cycle of the refrigeration unit work simultaneously, the high temperature stage compressor 51 in the refrigeration system starts to discharge high temperature and high pressure refrigerant, the refrigerant passes through the first loop of the condenser 70, namely the defrosting branch, and becomes high temperature and low pressure refrigerant, the refrigerant flows from bottom to top through the first frame pipe 10, then flows to the second frame pipe 20 at the cross beam of the refrigerator body at the position of the tee joint, flows to the fourth frame pipe 40 above the second frame pipe, and flows to the third frame pipe 30 along the outer edge of the refrigerator body, and the refrigerant in the second frame pipe 20 is gathered to the third frame pipe 30 through the second tee joint, and finally is sucked back by the high temperature compressor 51 for circulation.

In addition, the high-temperature and high-pressure refrigerant discharged from the high-temperature compressor enters the low-temperature compressor 61 through the second loop of the condenser 70, i.e., the branch of the high-temperature stage refrigeration cycle, cools the low-temperature compressor 61, and then returns to the condenser 70 for cooling. Then, the refrigerant is passed through a high-temperature drying filter 53 and dried to remove impurities such as water and oil in the refrigerant. And then passes through the high-temperature capillary tube 54 to throttle and reduce the pressure of the refrigerant, the refrigerant at the moment flows to the condensation evaporator 80, the refrigerant is evaporated in the condensation evaporator 80 to absorb heat, the high-temperature refrigerant coming out of the condensation evaporator takes away the condensation heat of the low-temperature refrigerant, and the heat is transferred to the ambient air through high-temperature circulation. The high temperature stage thus forms a single stage compression refrigeration cycle.

In a further embodiment of the present invention, the low-temperature-stage compression refrigeration cycle structure includes a low-temperature-stage compressor 61, an oil separator 62, a condensing evaporator 80, a low-temperature-stage dry filter 63, a low-temperature-stage capillary tube 64, and an evaporator 65; the low-temperature-stage refrigerant discharged from the low-temperature-stage compressor 61 passes through the oil separator 62, flows back to the low-temperature-stage compressor 61 after being filtered, flows to the condensing evaporator 80, exchanges heat with the high-temperature-stage refrigerant therein, is cooled into liquid, sequentially passes through the low-temperature-stage drying filter 63 and the low-temperature-stage capillary tube 64, enters the evaporator 65 for treatment, and finally flows back to the low-temperature-stage compressor 61 for circulation. In a further embodiment of the present invention, the low-temperature stage compression refrigeration cycle structure further includes an expansion tank 67, and the expansion tank 67 is connected between the evaporator 65 and the low-temperature stage compressor 61 through a capillary tube 66 provided at a front end thereof.

Specifically, the high-temperature and high-pressure refrigerant discharged from the low-temperature compressor 61 passes through the oil separator 62, so that the lubricating oil in the compressor can be effectively prevented from flowing into the condensing evaporator 80, and the heat transfer resistance can be reduced. The oil filtered by the oil separator 62 flows back to the low temperature compressor 61, and the refrigerant flows to the condensing evaporator 80, and this portion of refrigerant releases heat in the condensing evaporator 80, while the high temperature stage refrigerant in the condensing evaporator 80 is undergoing evaporation and absorption, so that the low temperature stage refrigerant exchanges heat with the high temperature stage refrigerant in the condensing evaporator 80, and the low temperature stage refrigerant is cooled to liquid. The low-temperature refrigerant liquid from the condensing evaporator 80 passes through a low-temperature drying filter 63 for drying to remove impurities such as moisture and oil in the refrigerator, passes through a low-temperature capillary tube 64 for throttling and pressure reduction, enters an evaporator 65 for absorbing heat of a cooled object to be evaporated and refrigerated, and obtains the required low temperature. The evaporator 65 of the ultra-low temperature refrigerator is designed in the refrigerator body, and is arranged on the side walls of the upper and lower refrigerator bodies in a serpentine shape in the refrigerator as shown in fig. 4. When the low temperature stage refrigerant evaporates in the evaporator 65, heat generated from the sample in the refrigerator is absorbed. The low temperature stage thus forms a single stage compression refrigeration cycle.

In addition, the low-temperature stage refrigeration cycle is provided with an expansion tank 67 structure, and a section of capillary tube 66 is arranged at the front end of the expansion tank 67. This configuration is such that when the cryogenic compressor is off, most of the cryogenic stage superheated steam enters the expansion tank 67, avoiding excessive pressure rise in the system above the maximum operating pressure of the system.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.