CN106500433B

CN106500433B - Freezer atmospheric pressure equalizer

Info

Publication number: CN106500433B
Application number: CN201611153255.7A
Authority: CN
Inventors: 赵金龙; 李建臣
Original assignee: Tianjin Tianshang Bingyuan Technology Development Co ltd
Current assignee: Tianjin Tianshang Bingyuan Technology Development Co ltd
Priority date: 2016-12-14
Filing date: 2016-12-14
Publication date: 2022-03-01
Anticipated expiration: 2036-12-14
Also published as: CN106500433A

Abstract

The invention discloses a freezer air pressure balancer, which comprises a thick pipe A, B, a thin pipe A, B and a heat insulation pipe; the two ends of the thick pipe A, B are provided with seal heads, the thick pipe A, B is vertically placed, and liquid is injected into the thick pipe; a first hole A is formed in an upper end socket of the thick pipe A, and a second hole A is formed in the upper pipe wall of the liquid level; a first hole B is formed in the upper end socket of the thick pipe B, and a second hole B is formed in the upper pipe wall of the liquid level; the thin pipe A comprises a first branch pipe A, a second branch pipe A and a third branch pipe A which are communicated, the first branch pipe A penetrates through the first hole A in a sealing mode and is inserted below the liquid level of the thick pipe A, the pipe orifice of the second branch pipe A is connected with the first hole B in a sealing mode, and the pipe orifice of the third branch pipe A is communicated with the outside; the thin pipe B comprises a first branch pipe B, a second branch pipe B and a third branch pipe B which are communicated, the first branch pipe B penetrates through the second hole B in a sealing mode and is inserted below the liquid level of the thick pipe B, the pipe orifice of the second branch pipe B is connected with the second hole A in a sealing mode, and the pipe orifice of the third branch pipe B is connected with the pipe orifice at one end of the heat insulation pipe in a sealing mode; the other end of the heat insulation pipe is sealed to penetrate through the refrigeration house, and the pipe opening is communicated with air in the refrigeration house. The invention can reduce the loss of cold energy and has low fault.

Description

Freezer atmospheric pressure equalizer

Technical Field

The invention relates to a refrigeration house, in particular to a refrigeration house air pressure balancer.

Background

At present, the temperature in a general cold storage is lower than the ambient temperature, particularly in a cold storage with a lower temperature, water vapor in the air in the cold storage is condensed and separated out to form frost, the air density is increased after the air temperature is reduced, and then the air pressure in the cold storage is reduced to be lower than the outdoor atmospheric pressure, so that pressure difference (high pressure outside the cold storage and low pressure inside the cold storage) occurs between the inside and the outside of the cold storage, and the lower the temperature of the cold storage, the higher the pressure difference is; another situation is: after the refrigeration house is operated for a plurality of hours in a refrigerating mode, the refrigerating equipment needs to stop refrigerating temporarily, the air cooler in the refrigeration house is heated and defrosted electrically, and the air pressure in the refrigeration house is increased sharply (the pressure outside the refrigeration house is low and the pressure inside the refrigeration house is high) due to the defrosting by the electric heating. When the pressure outside the refrigerator is low and the pressure inside the refrigerator is high, the structure of the heat-insulating layer of the refrigerator expands and deforms, and the tightness of the refrigerator body is damaged; when the pressure outside the refrigerator is high and the pressure inside the refrigerator is low, the heat-insulating layer of the refrigerator can sink and deform; in addition, the cold storage door is difficult to open due to unequal internal and external pressures. Therefore, at present, a balance window is generally arranged on a cold storage body and used for adjusting the internal pressure and the external pressure of the cold storage to balance the internal pressure and the external pressure.

The balance window is generally made into a rectangular shape, and the external dimensions are as follows: the length is 200mm and the width is 200mm, and the thickness of the cold storage thermal insulation storage body is generally approximate to that of the cold storage thermal insulation storage body. And (4) forming a hole with the diameter of about more than 200mm by 200mm on the heat-insulation storehouse body of the refrigeration house, and installing the balance window. The balance window closes or opens the sealing port by spring force. The well-known balance window is mostly used for 0-18 ℃ cold storage. For an ultra-low temperature refrigerator, such as a refrigerator for freezing red blood cells at the temperature of below-65 ℃, relevant technical experimental data are not disclosed, and corresponding application records are not recorded, and the test is carried out by adopting the balance window in the refrigerator at the temperature of below-65 ℃, the following problems are found, and the use requirements cannot be met:

(1) for a low-temperature refrigeration house, the sealing surface of the balance window is easy to frost, and after the balance window is opened and closed for many times, the sealing effect is damaged by frosting on the sealing surface, so that air leakage and cold leakage of the refrigeration house are caused, and the frosting is more and more serious. Air with large moisture content outside the refrigeration house continuously enters the refrigeration house, and the finned tube group of the air cooler in the refrigeration house is seriously frosted, and finally frost blockage occurs to prevent refrigeration.

(2) The balance window is opened or closed after overcoming the pressure value of the spring by utilizing the pressure difference between the inside and the outside of the warehouse, but under the condition of ultralow temperature, the elasticity of the steel spring is reduced and unstable, so that the balance window loses the function of adjusting balance.

(3) The balance window sealing opening needs to be provided with an electric heating wire, the balance window is prevented from being frozen and stuck and cannot be opened, but the electric heating wire fails due to fatigue burning, so that the balance window breaks down, and the balance window is not suitable for overhauling and maintaining.

(4) The balance window is installed, and a hole needs to be formed in the heat preservation warehouse body of the refrigeration house, so that the heat insulation capacity of the heat preservation warehouse body of the refrigeration house and the outside is reduced, and the weak link of the heat preservation of the refrigeration house is formed.

Disclosure of Invention

The invention provides a refrigeration house air pressure balancer which reduces cold energy loss and has low fault for solving the technical problems in the prior art.

The technical scheme adopted by the invention for solving the technical problems in the prior art is as follows: a freezer air pressure balancer comprises a thick pipe A, a thick pipe B, a thin pipe A, a thin pipe B and a heat insulation pipe; the two ends of the thick pipe A and the thick pipe B are provided with end sockets which are vertically arranged and liquid with the freezing point lower than the rated working temperature of the refrigeration house and the external environment temperature is injected into the pipes; a first hole A is formed in an end socket at the upper end of the thick pipe A, and a second hole A is formed in the pipe wall above the liquid level of the thick pipe A; a first hole B is formed in an end socket at the upper end of the thick pipe B, and a second hole B is formed in the pipe wall above the liquid level of the thick pipe B; the tubule a includes three interconnected branch tubes: the device comprises a first branch pipe A, a second branch pipe A and a third branch pipe A, wherein the first branch pipe A penetrates through the first hole A in a sealing mode and is inserted below the liquid level of the thick pipe A, the pipe orifice of the second branch pipe A is connected with the first hole B in a sealing mode, and the pipe orifice of the third branch pipe A is communicated with the outside air; the tubule B comprises three mutually communicated branch pipes: the heat insulation pipe comprises a first branch pipe B, a second branch pipe B and a third branch pipe B, wherein the first branch pipe B penetrates through the second hole B in a sealing mode and is inserted below the liquid level of the thick pipe B, the pipe orifice of the second branch pipe B is connected with the second hole A in a sealing mode, and the pipe orifice of the third branch pipe B is connected with the pipe orifice at one end of the heat insulation pipe in a sealing mode; the other end of the heat insulation pipe penetrates through the cold storage body in a sealing mode, and the pipe opening is communicated with the air inside the cold storage body.

The invention can also adopt the following technical scheme:

when the rated working temperature of the refrigeration house is more than or equal to-65 ℃, the liquid injected into the crude tube A and/or the crude tube B is ethyl silicone oil with the freezing point lower than-70 ℃.

The material of the thick pipe A and/or the thick pipe B is acrylic or stainless steel or a copper pipe.

And a hole is formed in the lower end socket of the thick pipe A and/or the thick pipe B, and a plug is connected in a sealing manner.

The pipe orifice of the third branch pipe A faces downwards or towards the horizontal direction, and a filter screen for filtering air is arranged in the pipe orifice.

The heat insulation pipe is made of ultra-high molecular weight polyethylene.

And the pipe orifice of the third branch pipe B is connected with the heat insulation pipe through screw threads.

Still include the shell, thick pipe A thick pipe B thin pipe A with thin pipe B arranges in the shell, the shell from interior to exterior includes heat preservation and protective layer in proper order.

The heat-insulating layer is made of flexible foam rubber and plastic.

The protective layer is made of metal, and a grid or a shutter is arranged at the position corresponding to the pipe orifice of the third branch pipe A.

The invention has the advantages and positive effects that:

(1) the mechanical sealing surface is avoided, the sealing failure and air leakage phenomena caused by frosting of the existing balance window are improved, and the defect that the balance window loses the adjusting function due to the fact that the elasticity of a steel spring is reduced and unstable under the ultralow temperature condition is avoided.

(2) And no electric heating wire is used, so that the defect that the balance window fails due to easy burning of the electric heating wire is avoided.

(3) The liquid level blocks the intercommunication of the air inside and outside the freezer at ordinary times, avoids cold and hot air convection exchange, reduces the cold energy loss.

(4) The wound surface of the cold storage body is small, only one heat insulation pipe penetrates through the cold storage body, the heat conductivity coefficient is small, and the wound surface is small, so that the cold energy loss is reduced, and the phenomenon of condensed frost nearby the cold energy loss is also reduced.

(5) The intensity of pressure difference between the inside and the outside of the cold storage is different when the cold storage is at different temperatures or different volumes, and the insertion depth value of the thin tube inserted into the thick tube liquid can be easily controlled by changing the filling amount of the liquid, so that the requirements of the ultra-low temperature cold storage at different scales can be met.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of the connection structure between the present invention and a thermal insulation storage body of a refrigeration storage.

In the figure: 1. the liquid level of the thick tube A; 2. a thick pipe A; 3. a thin tube A; 4. a filter screen; 5. a heat insulating pipe; 6. a thick pipe B; 7. a thin tube B; 8. the liquid level of the thick tube B; 9. plugging with a thread; 10. a cold storage heat preservation storage body; 11. a third branch pipe B; la, the insertion depth of the first branch pipe A into the liquid of the thick pipe A; ha. The lowest point of the second hole A is far from the liquid level of the thick pipe A.

Detailed Description

In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:

referring to fig. 1 to 2, a freezer air pressure balancer includes a thick tube A2, a thick tube B6, a thin tube A3, a thin tube B7, and a heat insulation tube 5; the two ends of the thick pipe A2 and the two ends of the thick pipe B6 are provided with end sockets, the thick pipe A2 and the thick pipe B6 are both vertically placed, and liquid with the freezing point lower than the rated working temperature of the refrigeration house and the temperature of the external environment is injected into the pipes; a first hole A is formed in an end socket at the upper end of the thick pipe A2, and a second hole A is formed in the pipe wall above the liquid level 1 of the thick pipe A; a first hole B is formed in an end socket at the upper end of the thick pipe B6, and a second hole B is formed in the pipe wall above the liquid level 2 of the thick pipe B; the thin tube A3 is a three-way tube and comprises three mutually communicated branch tubes which are respectively as follows: the device comprises a first branch pipe A, a second branch pipe A and a third branch pipe A, wherein the first branch pipe A penetrates through the first hole A in a sealing mode and is inserted below the liquid level 1 of the thick pipe A, the nozzle of the second branch pipe A is connected with the first hole B in a sealing mode, and the nozzle of the third branch pipe A is communicated with the outside air; the thin tube B7 is a three-way tube and comprises three mutually communicated branch tubes which are respectively as follows: the heat insulation pipe comprises a first branch pipe B, a second branch pipe B and a third branch pipe B11, wherein the first branch pipe B penetrates through the second hole B in a sealing mode and is inserted below the liquid level 2 of the thick pipe B, the pipe orifice of the second branch pipe B is connected with the second hole A in a sealing mode, and the pipe orifice of the third branch pipe B11 is connected with the pipe orifice at one end of the heat insulation pipe 5 in a sealing mode; the other end of the heat insulation pipe 5 penetrates through the cold storage body in a sealing mode, and the pipe opening is communicated with the air inside the cold storage body.

The insertion depth of the first branch pipe A into the liquid in the thick pipe A is La, the height of the lowest point of the second hole A from the liquid surface of the thick pipe A is Ha, the insertion depth of the first branch pipe B into the liquid in the thick pipe B is Lb, and the height of the lowest point of the second hole B from the liquid surface of the thick pipe B is Hb, La is Lb, Ha is Hb, Ha is greater than 2La, and Hb is greater than 2 Lb.

The heat insulation pipe 5 is also called a heat insulation pipe, has large heat resistance, can be made of materials with large heat resistance, and can be provided with heat insulation structures such as a heat insulation layer and the like to realize heat insulation inside and outside the pipeline.

The thick pipe A2 with thick pipe B6 is all vertical to be placed and intraductal all pours into the freezing point and is less than the rated operating temperature of freezer and the liquid of external environment temperature into, avoids the during operation to solidify, becomes the solid, can't form the liquid level.

When the rated working temperature of the refrigeration house is more than or equal to-65 ℃, the liquid injected into the crude tube A2 and/or the crude tube B6 can be ethyl silicone oil with the freezing point lower than-70 ℃ and other liquids. Through a large amount of proportion selection, the preferable liquid is ethyl silicone oil, which not only meets the requirement of no solidification at ultralow temperature, but also meets the requirement of user hygiene. The ethyl silicone oil has the following characteristics: the solidifying point is less than-70 ℃, the relative density is 0.95-1.05, the flash point is greater than 265 ℃ (open cup), the pH value is 5-7, the colorless to light yellow transparent liquid is dissolved in organic solvents such as toluene, ether, chloroform and the like, can be randomly mixed with petroleum products, has small volatility, small surface tension, no toxicity, no corrosiveness and aging resistance, and can be prepared into different viscosities according to the use requirements. It is widely used as insulating material in electrical industry, oil for precision instruments and meters, hydraulic oil, special lubricating oil, etc.

The material of the thick pipe A2 and/or the thick pipe B6 can be acrylic or stainless steel or copper pipe with low temperature resistance below-70 ℃.

The thick pipe A2 and/or the lower end head of the thick pipe B6 can be provided with a hole and can be connected with a plug 9 in a sealing way, and the plug is used for discharging sewage and updating ethyl silicone oil at irregular intervals.

The pipe orifice of the third branch pipe A is communicated with the outside air, the pipe orifice of the third branch pipe A can face downwards or towards the horizontal direction, and a filter screen 4 for filtering the air can be arranged in the pipe orifice. The pipe orifice of the third branch pipe A is communicated with the air of the environment outside the refrigeration house, a filter screen 4 is arranged for preventing foreign matters or winged insects and the like from entering, and the orifice can face downwards or towards the horizontal direction in order to prevent dust from falling into the orifice and is not suitable for facing upwards.

The heat insulation pipe 5 has larger heat resistance so as to prevent heat conduction inside and outside the refrigeration house and cold energy loss. The heat insulation pipe can be made of ultra-high molecular weight polyethylene or other materials with high heat resistance.

The nozzle of the third branch pipe B11 is connected with the heat insulation pipe 5 in a screw thread mode. The other parts of the air pressure balancer can be made of low-temperature-resistant acrylic or nontoxic plastic or stainless steel or copper pipes, and the parts can be connected by screw threads.

The invention also comprises a shell, wherein the thick pipe A, the thick pipe B, the thin pipe A and the thin pipe B are arranged in the shell, and the shell can sequentially comprise a heat-insulating layer and a protective layer from inside to outside. The heat-insulating layer reduces heat energy exchange, reduces cold energy loss and prevents frosting. The protective layer protects the air pressure balancer from external force impact and is easily connected with other members.

The insulating layer can be made of flexible foam rubber and plastic. The flexible foam rubber plastic has good heat preservation and the process for manufacturing the shell is simple.

The protective layer is made of metal, and a grid or a shutter is arranged at the position corresponding to the pipe orifice of the third branch pipe A. So as to be beneficial to the exchange of air inside and outside the refrigeration house.

The refrigeration house heat preservation warehouse body 10 can comprise an inner layer, an outer layer and a middle layer, wherein the inner layer and the outer layer can be stainless steel plates or plastic-coated steel plates, and the middle layer can be a polyurethane heat preservation layer.

When the refrigeration house is used for storing frozen red blood cells, the working rated temperature of the refrigeration house is-65 ℃ and below, the refrigeration house is an ultra-low temperature refrigeration house, and the specific scheme is as follows:

a freezer air pressure balancer, can be used in the ultra-low temperature freezer, including the thick tube A2, thick tube B6, tubule A3, tubule B7 and heat insulating tube 5; the upper end and the lower end of the thick pipe A2 are both provided with end sockets for sealing pipe orifices, ethyl silicone oil is injected into the thick pipe A, the end socket at the upper end of the thick pipe A is provided with a first hole A, and a pipe wall at the position above the liquid level and at the height Ha from the liquid level is provided with a second hole A; the upper end and the lower end of the thick pipe B6 are both provided with end sockets for sealing pipe orifices, ethyl silicone oil is injected into the thick pipe B, the end socket at the upper end of the thick pipe B is provided with a first hole B, and a pipe wall with the distance of Hb from the liquid level above the liquid level is provided with a second hole B; the tubule A3 is a three-way pipe, which is provided with three mutually communicated branch pipes, which are respectively: the device comprises a first branch pipe A, a second branch pipe A and a third branch pipe A, wherein the first branch pipe A penetrates through the first hole A in a sealing mode and is inserted below the liquid level 1 of the thick pipe A, the distance between the pipe orifice of the first branch pipe A and the liquid level 1 of the thick pipe A is La, namely the insertion depth is La, the pipe orifice of the second branch pipe A is connected with the first hole B in a sealing mode, and the pipe orifice of the third branch pipe A is communicated with the outside air; the thin tube B7 is a three-way tube which is provided with three mutually communicated branch tubes which are respectively as follows: the heat insulation pipe comprises a first branch pipe B, a second branch pipe B and a third branch pipe B11, wherein the first branch pipe B penetrates through the second hole B in a sealing mode and is inserted below the liquid level 2 of the thick pipe B, the depth of the inserted liquid level is Lb, the pipe orifice of the second branch pipe B is connected with the second hole A in a sealing mode, and the pipe orifice of the third branch pipe B11 is connected with the pipe orifice at one end of the heat insulation pipe 5 in a sealing mode; the other end of the heat insulation pipe 5 penetrates through the cold storage body in a sealing mode, and the pipe opening is communicated with air in the cold storage. Let La be Lb, Ha be Hb, Ha >2La, Hb >2 Lb.

The working principle of the invention is as follows:

when the pressure outside the refrigerator is high and the pressure inside the refrigerator is low, the air outside the refrigerator enters a third branch pipe A of a thin pipe A3 through a filter screen 4 and then is divided to enter a first branch pipe A and a second branch pipe A, wherein the first branch pipe A penetrates through the first hole A in a sealing mode and is inserted below the liquid level 1 of the thick pipe A, and the pipe orifice of the second branch pipe A is connected with the first hole B in a sealing mode; when the liquid column pressure of La height is overcome, the air entering the first branch pipe A enters the upper space of the liquid level of the thick pipe A2 in a bubble mode and then enters the internal space of the cold storage through the heat insulation pipe 5, so that the air is added and pressurized in the cold storage, and the effect of balancing the air pressure inside and outside the cold storage is achieved; because the second branch pipe A is communicated with the upper space of the liquid level of the thick pipe B6, air outside the refrigerator enters the second branch pipe A and then enters the upper space of the liquid level of the thick pipe B6, the air has the tendency of pressing liquid in the thick pipe B6 into the thin pipe B7, but the air outside the refrigerator in the thick pipe A2 overcomes the liquid column pressure at the height of La before the liquid column in the thin pipe B7 is fully pressed because Ha is greater than 2La and Hb is greater than 2Lb, and the air is introduced into the refrigerator in a bubble form through the heat insulation pipe 5. It was therefore concluded that: when the pressure outside the cold storage is high and the pressure inside the cold storage is low, the air outside the cold storage enters the thin tube A3 through the filter screen 4, and when the air overcomes the liquid column pressure of La height, the air enters the upper space of the liquid level of the thick tube A2 in a bubble mode, so that the air enters the cold storage through the heat insulation tube 5, and the air is added and pressurized in the cold storage to play a role in balancing the air pressure inside and outside the cold storage.

When the external pressure of the refrigerator is low and the internal pressure of the refrigerator is high, the air in the refrigerator enters the thin tube B7 through the heat insulation tube 5, enters the third branch tube B of the thin tube B7, then is divided into the first branch tube B and the second branch tube B, the first branch tube B penetrates through the second hole B in a sealing manner and is inserted below the liquid level of the thick tube B, and the tube opening of the second branch tube B is connected with the second hole A in a sealing manner, so that the air entering the first branch tube B from the refrigerator enters the upper space of the thick tube B6 in a bubble form when the liquid column pressure of Lb height is overcome, then enters the third branch tube A through the second branch tube A of the thin tube A3, and is discharged out of the refrigerator after passing through the filter screen of the third branch tube A, so that the air pressure inside and outside the refrigerator is reduced, and the effect of balancing the internal and external air pressures of the refrigerator is achieved; the air from the refrigerator which is shunted into the second branch pipe B directly enters the upper space of the liquid level of the thick pipe A2, the air tends to press the liquid in the thick pipe A2 into the thin pipe A3, but the air from the refrigerator overcomes the liquid column pressure at the Lb height before the liquid column in the thin pipe A3 is fully pressed due to Ha >2La and Hb >2Lb, enters the upper part of the liquid level of the thick pipe B6 in the form of bubbles, and then passes through the filter screen 4 on the thin pipe A3 to be introduced out of the refrigerator. It was therefore concluded that: when the pressure outside the cold storage is low and the pressure inside the cold storage is high, the air inside the cold storage enters the thin tube B7 through the heat insulation tube 5, and when the air inside the cold storage overcomes the liquid column with Lb height, the air enters the upper space of the thick tube B6 in a bubble form, and then enters the outside of the cold storage through the filter screen 4 on the thin tube A3 to release air and reduce pressure in the cold storage, so that the effect of balancing the air pressure inside and outside the cold storage is achieved.

The above-mentioned embodiments are only for illustrating the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to carry out the same, and the present invention shall not be limited to the embodiments, i.e. the equivalent changes or modifications made within the spirit of the present invention shall fall within the scope of the present invention.

Claims

1. A freezer air pressure balancer is characterized by comprising a thick pipe A, a thick pipe B, a thin pipe A, a thin pipe B and a heat insulation pipe; the two ends of the thick pipe A and the thick pipe B are provided with end sockets which are vertically arranged and liquid with the freezing point lower than the rated working temperature of the refrigeration house and the external environment temperature is injected into the pipes; a first hole A is formed in an end socket at the upper end of the thick pipe A, and a second hole A is formed in the pipe wall above the liquid level of the thick pipe A; a first hole B is formed in an end socket at the upper end of the thick pipe B, and a second hole B is formed in the pipe wall above the liquid level of the thick pipe B; the tubule a includes three interconnected branch tubes: the device comprises a first branch pipe A, a second branch pipe A and a third branch pipe A, wherein the first branch pipe A penetrates through the first hole A in a sealing mode and is inserted below the liquid level of the thick pipe A, the pipe orifice of the second branch pipe A is connected with the first hole B in a sealing mode, and the pipe orifice of the third branch pipe A is communicated with the outside air; the tubule B comprises three mutually communicated branch pipes: the heat insulation pipe comprises a first branch pipe B, a second branch pipe B and a third branch pipe B, wherein the first branch pipe B penetrates through the second hole B in a sealing mode and is inserted below the liquid level of the thick pipe B, the pipe orifice of the second branch pipe B is connected with the second hole A in a sealing mode, and the pipe orifice of the third branch pipe B is connected with the pipe orifice at one end of the heat insulation pipe in a sealing mode; the other end of the heat insulation pipe hermetically penetrates through the cold storage body, and the pipe orifice is communicated with the air inside the cold storage body;

let La be the depth of insertion of first branch pipe A into thick pipe A liquid, Ha be the height of second hole A lowest point from thick pipe A liquid level, Lb be the depth of insertion of first branch pipe B into thick pipe B liquid, Hb be the height of second hole B lowest point from thick pipe B liquid level, make La be Lb, Ha be Hb, Ha >2La, Hb >2 Lb.

2. The air pressure balancer for the refrigeration house according to claim 1, wherein when the rated working temperature of the refrigeration house is not less than-65 ℃, the liquid injected into the crude pipe A and/or the crude pipe B is ethyl silicone oil with the freezing point lower than-70 ℃.

3. The freezer air pressure balancer of claim 1, characterized in that the material of said thick tube A and/or said thick tube B is acrylic or stainless steel or copper tube.

4. The refrigeration house air pressure balancer according to claim 1, characterized in that a hole is formed in the lower end head of the thick pipe A and/or the thick pipe B, and a plug is connected in a sealing manner.

5. The freezer air pressure balancer of claim 1, wherein the third branch pipe A has a pipe opening facing downward or toward the horizontal direction, and a filter screen for filtering air is provided in the pipe opening.

6. The freezer air pressure balancer of claim 1, wherein the heat insulating tube is made of ultra high molecular weight polyethylene.

7. The freezer air pressure balancer of claim 1, wherein the orifice of the third branch pipe B is screwed to the heat insulating pipe.

8. The freezer air pressure balancer of claim 1, further comprising a housing, wherein the thick tube A, the thick tube B, the thin tube A and the thin tube B are arranged in the housing, and the housing sequentially comprises a heat insulation layer and a protective layer from inside to outside.

9. The freezer air pressure balancer of claim 8, wherein the insulation layer is made of flexible foam rubber.

10. The freezer air pressure balancer of claim 8, wherein the protective layer is made of metal and is provided with a grid or louver at the pipe orifice corresponding to the third branch pipe A.