CN111486635A - Low-temperature storage device and control method thereof - Google Patents

Abstract

The invention provides a low-temperature storage device and a control method thereof, which relate to the technical field of low-temperature storage, and are used to solve the problem that the compressor of the existing low-temperature refrigerating device has a large load and the protector trips easily when the refrigeration system starts to operate. The low-temperature storage device includes: a fourth connection branch, one end of the fourth connection branch is connected with the air outlet of the liquid separator, and the other end is connected with the air inlet of the compressor; a control valve, the control valve is arranged on the first Four connecting branches; an expansion vessel, the expansion vessel is connected to a fourth connecting branch on the downstream side of the control valve; a detecting device, the detecting device is configured to detect a pressure value in the fourth connecting branch upstream of the control valve, and When the pressure value is greater than or equal to the threshold value, the control valve is opened, so that the refrigerant flowing out of the air outlet of the liquid separator flows into the expansion container along the fourth connection branch. The present invention can be used for low temperature storage of articles.

Description

A low temperature storage device and control method thereof

technical field

The invention relates to the technical field of low temperature storage, in particular to a low temperature storage device and a control method thereof.

Background technique

With the development of the times, there are more and more demands for low-temperature storage devices in the market. For storage devices with storage temperature of -40°C and above, a single-stage refrigeration cycle is generally used, but if the required temperature is lower, a single-stage refrigeration cycle The refrigeration cycle cannot meet the requirements. For storage devices with temperature requirements of -40°C to -60°C or below -60°C, automatic cascade refrigeration technology is generally used for refrigeration.

However, in the existing cascade refrigeration system, when the compressor is just turned on and warmed up, since the refrigeration system has not yet established a stable operation state, the exhaust and suction pressures of the compressor are high at this time, and the compressor is subjected to a large load , the protector of the compressor is easily tripped, thereby affecting the normal operation of the refrigeration system and reducing the refrigeration effect of the low-temperature storage device.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a low-temperature storage device and a control method thereof, which are used to solve the problem that the compressor of the existing low-temperature refrigerating device has a large load when the refrigeration system starts to operate, and the protector is easily tripped.

In order to achieve the above object, in the first aspect, an embodiment of the present invention provides a low-temperature storage device, comprising: a box body, the box body is used to form a refrigeration space; and a refrigeration system is used to refrigerate the refrigeration system. Space refrigeration; the refrigeration system includes: a compressor, which has a suction port and an exhaust port; a liquid separator, which has a liquid inlet, a liquid outlet and an air outlet, and the liquid outlet The port is located at the bottom of the liquid separator, and the air outlet is located at the top of the liquid separator; a first connecting branch, one end of the first connecting branch is connected with the exhaust port, and the other end is connected with the exhaust port. The liquid inlet is connected; the condenser is arranged on the first connecting branch; the second connecting branch, one end of the second connecting branch is connected with the liquid outlet, and the other is connected with the liquid outlet. One end is connected to the suction port; a first heat exchanger, the first heat exchanger has a first flow path and a second flow path that can perform heat exchange, and the first flow path is arranged at the second connection a branch; a first throttling device, the first throttling device is arranged on the second connecting branch, and is located between the inlet end of the first flow path and the liquid separator; a third connecting branch , the first end of the third connecting branch is connected with the air outlet, and the second end is connected with the inlet end of the first flow path or the middle of the first flow path; the second flow path is provided with on the third connecting branch; an evaporator, the evaporator is arranged on the third connecting branch; a second throttling device, the second throttling device is arranged on the third connecting branch, and is located between the second flow path and the evaporator; a fourth connection branch, one end of the fourth connection branch is connected with the air outlet, and the other end is connected with the air inlet; control a valve, the control valve is arranged on the fourth connecting branch; an expansion vessel, the expansion vessel is connected to the fourth connecting branch on the downstream side of the control valve; a detection device, the detection device is configured to detect a pressure value in the fourth connection branch upstream of the control valve, and when the pressure value is greater than or equal to a threshold, open the control valve to allow at least a portion of the air outlet to flow out The refrigerant flows into the expansion vessel along the fourth connecting branch.

In a second aspect, an embodiment of the present invention provides a control method for the low-temperature storage device described in the first aspect, including the following steps: after the refrigeration system starts to work, obtain a fourth connection branch located upstream of the control valve When the pressure value is greater than or equal to the threshold value, open the control valve, so that at least a part of the refrigerant flowing out of the air outlet of the liquid separator can flow into the expansion container along the fourth connection branch .

In the low-temperature storage device and the control method thereof provided by the embodiments of the present invention, since the refrigeration system further includes a fourth connection branch, one end of the fourth connection branch is connected with the air outlet, and the other end is connected with the air inlet; the control valve, The control valve is arranged on the fourth connecting branch; the expansion vessel is connected to the fourth connecting branch on the downstream side of the control valve, and the detection device is configured to detect the fourth connecting branch upstream of the control valve. In this way, when the compressor starts to start, the detection device can detect the pressure value in the fourth connecting branch upstream of the control valve, and when the above-mentioned pressure value is larger, that is, greater than or equal to the threshold value, the detection device will The control valve can be opened, so that at least a part of the high-temperature refrigerant flowing out of the air outlet of the liquid separator flows into the expansion container along the fourth connection branch, so as to reduce the amount of refrigerant in the refrigeration system. Due to the reduction of the amount of refrigerant in the refrigeration system, the load of the compressor can be reduced to reduce the suction pressure and discharge pressure of the compressor, so that the protector of the compressor can be prevented from tripping, thereby ensuring the normal operation of the refrigeration system. The operation of the working conditions is further beneficial to ensure the cooling effect of the low-temperature storage device.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 is a schematic structural diagram of a low-temperature storage device in an embodiment of the present invention;

2 is a schematic diagram of the connection between the refrigeration system and the inner tank of the low-temperature storage device in the embodiment of the present invention;

3 is a schematic diagram of the layout of components in a compressor compartment of a low-temperature storage device in an embodiment of the present invention;

4 is a schematic diagram of the connection of the refrigeration system of the low-temperature storage device in the embodiment of the present invention;

5 is a schematic cross-sectional view of a first heat exchanger in an embodiment of the present invention;

6 is a circuit diagram of a refrigeration system of a cryogenic storage device in some embodiments of the present invention;

7 is a circuit diagram of a refrigeration system of a cryogenic storage device in other embodiments of the present invention;

FIG. 8 is a control flow chart of a refrigeration system of a low temperature storage device in some embodiments of the present invention.

Reference signs: box 100; outer shell 110; inner tank 120; bottom wall 121; top wall 122; side wall 123; rear wall 124; door body 200; refrigeration system 300; compressor 1; suction port 11; exhaust port 12; liquid separator 2; liquid inlet 21; liquid outlet 22; air outlet 23; first connection branch 3a; second connection branch 3b; third connection branch 3c; fourth connection branch 3d; The first heat exchanger 4a; the second heat exchanger 4b; the third heat exchanger 4c; the first flow path 41; the second flow path 42; the third flow path 43; the fourth flow path 44; the fifth flow path 45; sixth flow path 46; inner tube 401; outer tube 402; condenser 5a; evaporator 5b; heat exchange tube 51; first throttle device 6a; second throttle device 6b; third throttle device 6c; control valve 7a; expansion vessel 7b; detection device 7c; pressure sensor 71; controller 72; oil separator 8; oil return port 81; oil return pipe 82; first dry filter 9a; second dry filter 9b.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

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

The terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connected, or integrally connected; the term "connected" can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements; for those of ordinary skill in the art, the above terms can be understood in specific situations Specific meanings in the present invention.

In the first aspect, as shown in FIG. 1 , an embodiment of the present invention provides a low-temperature storage device, including: a box body 100 , which is used to form a refrigeration space; and a door body 200 , which is used to open or close the door body 200 cooling space.

The above-mentioned low-temperature storage device may be a freezer (as shown in FIG. 1 ), a refrigerator, etc., which is not specifically limited herein.

As shown in FIG. 2 and FIG. 3 , the low-temperature storage device further includes a refrigeration system 300, and the refrigeration system 300 is used for refrigerating the refrigeration space; as shown in FIG. 6 and FIG. 7, the refrigeration system 300 includes: a compressor 1, a compressor 1 has a suction port 11 and an exhaust port 12; the liquid separator 2, the liquid separator 2 has a liquid inlet 21, a liquid outlet 22 and an air outlet 23, the liquid outlet 22 is located at the bottom of the liquid separator 2, and the air outlet 23 is located at the top of the liquid separator 2; the first connecting branch 3a, one end of the first connecting branch 3a is connected with the exhaust port 12, and the other end is connected with the liquid inlet 21; the condenser 5a, the condenser 5a is provided On the first connecting branch 3a; the second connecting branch 3b, one end of the second connecting branch 3b is connected with the liquid outlet 22, and the other end is connected with the suction port 11; the first heat exchanger 4a, the first A heat exchanger 4a has a first flow path 41 and a second flow path 42 capable of heat exchange, the first flow path 41 is provided on the second connecting branch 3b; the first throttle device 6a, the first throttle device 6a is provided On the second connecting branch 3b, and between the inlet end A of the first flow path 41 and the liquid separator 2; the third connecting branch 3c, the first end of the third connecting branch 3c is connected with the air outlet 23 , the second end is connected with the inlet end A of the first flow path 41 (as shown in FIG. 7 ) or the middle of the first flow path 41 (as shown in FIG. 6 ); the second flow path 42 is arranged in the third connection branch 3c Evaporator 5b, the evaporator 5b is arranged on the third connecting branch 3c, and is located on the downstream side of the second flow path 42; the second throttling device 6b, the second throttling device 6b is arranged on the third connecting branch 3c, and between the second flow path 42 and the evaporator 5b.

The middle of the first flow path 41 refers to the part of the first flow path 41 except for both ends.

As shown in FIGS. 6 and 7 , the refrigeration system 300 further includes: a fourth connection branch 3d, one end of the fourth connection branch 3d is connected to the air outlet 23, and the other end is connected to the air inlet 11; a control valve 7a, the control valve 7a is provided on the fourth connection branch 3d; the expansion vessel 7b, the expansion vessel 7b is connected to the fourth connection branch 3d on the downstream side of the control valve 7a; the detection device 7c, the detection device 7c is configured to detect The pressure value p in the fourth connecting branch 3d upstream of the control valve 7a, and when the pressure value p is greater than or equal to the threshold value _p0 , the control valve 7a is opened, so that at least a part of the refrigerant flowing out of the air outlet 23 flows along the first The four connecting branches 3d flow into the expansion vessel 7b.

Wherein, the first throttling device 6a may be a throttling capillary (as shown in FIG. 7 ) or a throttling valve (as shown in FIG. 6 ), which is not specifically limited here; the second throttling device 6b may be The throttle capillary (as shown in FIG. 7 ) may also be a throttle valve (as shown in FIG. 6 ), which is not specifically limited here.

The above refrigeration system 300 uses a mixed refrigerant, which includes a high temperature grade refrigerant (that is, a refrigerant with a higher boiling point, such as R600A) and a low temperature grade refrigerant (that is, a refrigerant with a lower boiling point, such as R23A) ), the cooling process is as follows:

As shown in Figure 6, after the mixed refrigerant is compressed by the compressor 1, it becomes a high-temperature and high-pressure vapor, and after entering the condenser 5a for condensation, the high-temperature refrigerant condenses into a liquid state, and the low-temperature refrigerant has a low boiling point. Condensation does not liquefy it, so it remains gaseous. Then the high temperature refrigerant and the low temperature refrigerant enter the liquid separator 2, and the liquid high temperature refrigerant flows out from the liquid outlet 22 at the bottom of the liquid separator 2 under the action of gravity, and is cooled down by the first throttling device 6a. After being compressed, it enters the first flow path 41 in the first heat exchanger 4a; while the gaseous low-temperature refrigerant enters the second flow path 42 in the first heat exchanger 4a through the air outlet 23 at the top of the liquid separator 2 It exchanges heat with the high temperature refrigerant in the first flow path 41, and the high temperature refrigerant evaporates and absorbs heat in the first flow path 41, so that the low temperature refrigerant condenses into a liquid state in the second flow path 42, and then the liquid The low-temperature refrigerant flows out from the first heat exchanger 4a, and after being cooled and reduced by the second throttling device 6b, enters the evaporator 5b for evaporation and heat absorption, so that the cooling space is cooled and cooled, and finally flows out from the evaporator 5b The low-temperature-grade refrigerant returned to the first flow path 41 of the first heat exchanger 4a is mixed with the high-temperature-grade refrigerant, and the formed mixed refrigerant flows into the suction port 11 of the compressor 1 along the second connecting branch 3b for next refrigeration cycle.

In the low-temperature storage device provided in the embodiment of the present invention, as shown in FIG. 6 , since the refrigeration system 300 further includes a fourth connection branch 3d, one end of the fourth connection branch 3d is connected to the air outlet 23, and the other end is connected to the air inlet 11 is connected; the control valve 7a, the control valve 7a is arranged on the fourth connecting branch 3d; the expansion vessel 7b, the expansion vessel 7b is connected with the fourth connecting branch 3d on the downstream side of the control valve 7a, and the detection device 7c, detects The means 7c are configured to detect the pressure value p in the fourth connection branch 3d upstream of the control valve 7a, so that when the compressor 1 starts to start, the detection means 7c can detect the fourth connection branch upstream of the control valve 7a The pressure value p in the road 3d, when the above-mentioned pressure value p is larger, that is, greater than or equal to the threshold value p ₀ , the detection device 7c can open the control valve 7a, so that the high temperature of at least a part of the air outlet 23 of the liquid separator 2 flows out. The primary refrigerant flows into the expansion vessel 7b along the fourth connecting branch 3d to reduce the amount of refrigerant in the refrigeration system 300 . Due to the reduction of the amount of refrigerant in the refrigeration system 300, the load of the compressor 1 can be reduced to reduce the suction pressure and the discharge pressure of the compressor 1, so that the trip of the protector of the compressor 1 can be avoided, thereby ensuring the The operation of the refrigeration system 300 under normal working conditions is further beneficial to ensure the refrigeration effect of the low-temperature storage device.

In the refrigeration system 300, the detection device 7c may have the following structure: As shown in FIG. 6, the detection device 7c includes: a pressure sensor 71, which is configured to detect the pressure value p; a controller 72, which is configured to When the pressure value p is greater than or equal to the threshold value p ₀ , the control valve 7a is opened so that at least a part of the refrigerant flowing out of the air outlet 23 can flow into the expansion vessel 7b along the fourth connection branch 3d. The control valve 7a is controlled by the controller 72, so that the controller 72 can more accurately control the opening and closing of the control valve 7a according to the pressure value p fed back by the pressure sensor 71.

Of course, in addition to the above structure, the detection device 7c may also not include the controller 72, the pressure sensor 71 is connected to the control valve 7a, and the signal fed back by the pressure sensor 71 is used to trigger the opening and closing of the control valve 7a, that is: when When the pressure value p is greater than or equal to the threshold value _p0 , the pressure sensor 71 sends a trigger signal to open the control valve 7a.

Among them, the pressure sensor 71 can be arranged at the air outlet 23 of the dispenser 2 (as shown in FIG. 6 ), or at a position close to the control valve 7a (as shown in FIG. 7 ), and the details can be more according to the actual situation. Depends.

In the refrigeration system 300, the low-temperature refrigerant entering the fourth connecting branch 3d from the air outlet 23 of the liquid separator 2 has a relatively high pressure because it has not undergone the evaporation process. Entering the suction port 11 of the compressor 1 will cause a certain impact to the compressor 1, and it is easy to damage the compressor 1. In order to avoid the impact of the high-pressure low-temperature refrigerant in the fourth connecting branch 3d on the compressor 1 7, the refrigeration system 300 further includes a third throttling device 6c, the third throttling device 6c is arranged on the fourth connecting branch 3d, and is located at the connection point between the expansion vessel 7b and the fourth connecting branch 3d downstream side. By arranging the third throttling device 6c, the temperature and pressure of the low-temperature refrigerant vapor on the fourth connecting branch 3d can be lowered, so that the low-temperature refrigerant with higher pressure can be prevented from directly entering the suction port 11 to the compressor. 1, which is beneficial to prolong the life of the compressor 1.

The third throttling device 6c may be a throttling capillary (as shown in FIG. 6 ) or a throttling valve, which is not specifically limited herein.

In the refrigeration system 300, the type of the first heat exchanger 4a is not unique. For example, as shown in FIG. 2 and FIG. 4, the first heat exchanger 4a may be a casing heat exchanger. As shown in FIG. The heat exchanger 4 a includes an inner tube 401 and an outer tube 402 sleeved outside the inner tube 401 . The inner tube 401 forms a first flow path 41 , and the gap between the inner tube 401 and the outer tube 402 forms a second flow path 42 . When the refrigeration system 300 works, the high temperature refrigerant in the inner pipe 401 exchanges heat with the low temperature refrigerant in the gap between the inner pipe 401 and the outer pipe 402 through the pipe wall of the inner pipe 401 .

In the embodiment in which the first heat exchanger 4a is a casing heat exchanger, the positions of the first flow path 41 and the second flow path 42 can also be reversed, that is, the second flow path 42 is formed in the inner pipe 401, and the inner pipe The gap between 401 and the outer tube 402 forms the first flow path 41 .

In addition to being a jacket-and-tube heat exchanger, the first heat exchanger 4a can also be a shell-and-tube heat exchanger. The first heat exchanger 4a includes a shell and a heat exchange pipeline arranged in the shell. The heat exchange tube The passage forms a first flow passage 41, and a second flow passage 42 is formed between the heat exchange pipe and the inner wall of the casing.

In order to improve the cooling effect of the refrigeration system 300, as shown in FIG. 7, the refrigeration system 300 further includes a second heat exchanger 4b, and the second heat exchanger 4b has a third flow path 43 and a fourth flow path capable of heat exchange 44; the third flow path 43 and the fourth flow path 44 are all arranged in the third connecting branch 3c, and the third flow path 43 is located between the second flow path 42 and the second throttle device 6b, and the fourth flow path 44 is located between the evaporator 5b and the first flow path 41 . When the refrigeration system 300 is in operation, the low-temperature refrigerant flows out from the second flow path 42 of the first heat exchanger 4a, and then enters the third flow path 43 of the second heat exchanger 4b to become a supercooled liquid state The low temperature refrigerant passes through the second throttling device 6b, enters the evaporator 5b, and then flows into the fourth flow path 44 of the second heat exchanger 4b, and uses the waste heat of the evaporator 5b to cool the low temperature stage refrigerant in the third flow path 43. The refrigerant cools down, and finally the low-temperature-grade refrigerant flowing out from the fourth flow path 44 and the liquid high-temperature-grade refrigerant merge in the first flow path 41 of the first heat exchanger 4a, and flow along the third connecting branch 3c to the compression The suction port 11 of the machine 1. By arranging the second heat exchanger 4b, the low temperature refrigerant evaporated by the evaporator 5b in the fourth flow path 44 can be used to exchange heat with the low temperature refrigerant in the third flow path 43, so as to reduce the third The temperature of the low-temperature refrigerant in the flow path 43 can be reduced, so that the temperature of the low-temperature refrigerant at the inlet of the evaporator 5b can be lowered, so as to improve the cooling effect of the evaporator 5b, so that the refrigerating space of the low-temperature storage device can reach a higher temperature. low temperature.

Wherein, the second heat exchanger 4b can be a casing heat exchanger (as shown in Figures 2 and 4), the casing heat exchanger includes an inner heat exchange tube and an outer casing sleeved outside the inner heat exchange tube, A third flow path 43 is formed in the inner heat exchange tube, and a fourth flow path 44 is formed between the inner heat exchange tube and the outer sleeve; Three flow path 43 . In addition, the second heat exchanger 4b can also be a shell-and-tube heat exchanger, the shell-and-tube heat exchanger includes a shell and a heat exchange pipeline arranged in the shell, and the heat exchange pipeline forms a third flow path 43, A fourth flow path 44 is formed between the heat exchange pipeline and the inner wall of the casing.

In order to facilitate the separation of the mixed refrigerant in the liquid separator 2, as shown in FIG. 7, the refrigeration system 300 further includes a third heat exchanger 4c, and the third heat exchanger 4c has a fifth flow path 45 capable of heat exchange and a first heat exchanger 4c. Six flow paths 46; the fifth flow path 45 is arranged on the first connecting branch 3a, and is located between the condenser 5a and the liquid separator 2; the sixth flow path 46 is arranged on the second connecting branch 3b, and is located in Between the first heat exchanger 4a and the intake port 11 . By providing the third heat exchanger 4c, the mixed refrigerant with a higher temperature after condensation by the condenser 5a can generate heat in the fifth flow path 45 and the mixed refrigerant with a lower temperature in the sixth flow path 46 exchange to reduce the temperature of the mixed refrigerant in the fifth flow path 45, so that after the fifth flow path 45 flows out of the liquid separator 2 where the mixed refrigerant enters, the mixed refrigerant with a lower temperature is more likely to occur in the liquid separator 2 Gas-liquid separation, so that the separated low-temperature refrigerant can maintain a relatively low temperature and enter the first heat exchanger 4a, which is conducive to the heat exchange, so that the exchange rate of the first heat exchanger 4a can be improved. Thermal efficiency.

Wherein, the third heat exchanger 4c can be a casing heat exchanger (as shown in Figures 2 and 4), the casing heat exchanger includes an inner heat exchange tube and an outer casing sleeved outside the inner heat exchange tube, A fifth flow path 45 is formed in the inner heat exchange tube, and a sixth flow path 46 is formed between the inner heat exchange tube and the outer sleeve; or a sixth flow path 46 is formed in the inner heat exchange tube, and a sixth flow path 46 is formed between the inner heat exchange tube and the outer sleeve. Five flow paths 45 . In addition, the third heat exchanger 4c can also be a shell-and-tube heat exchanger, the shell-and-tube heat exchanger includes a shell and a heat exchange pipeline arranged in the shell, and the heat exchange pipeline forms the fifth flow path 45, A sixth flow path 46 is formed between the heat exchange pipeline and the inner wall of the casing.

In the low-temperature storage device according to the embodiment of the present invention, as shown in FIG. 1 and FIG. 2 , the box 100 includes an outer shell 110 , an inner container 120 and a heat insulating layer between the outer shell 110 and the inner container 120 , and the inner container 120 is used to form The refrigerating space; the inner tank 120 includes: a bottom wall 121 and a top wall 122 spaced along the height direction H of the box body 100; two side walls 123 spaced apart along the width direction X of the box body 100; rear wall 124 .

Among them, as shown in FIG. 1 and FIG. 2 , the width direction X of the box body 100 is a direction perpendicular to the height direction H and the depth direction Y of the box body 100 , and the depth direction Y of the box body 100 is when the door body 200 is closed. In the case of a refrigerated space, the direction is parallel to the thickness direction of the door body 200 .

In order to improve the cooling effect of the evaporator 5b on the refrigeration space, as shown in FIG. 2 , the evaporator 5b includes a heat exchange tube 51 , and the heat exchange tube 51 is arranged on the outer surfaces of the top wall 122 , the rear wall 124 and the two side walls 123 . . By arranging the heat exchange tubes 51 on the outer surfaces of the top wall 122, the rear wall 124 and the two side walls 123, the contact area between the heat exchange tubes 51 and the inner tank 120 is increased, and the The heat exchange efficiency of the refrigerating space inside the bladder 120 is beneficial to make the refrigerating space reach a lower temperature, so as to improve the use range of the low-temperature storage device.

As shown in FIG. 7 , the refrigeration system 300 further includes an oil separator 8. The oil separator 8 is arranged on the first connecting branch 3a and located between the compressor 1 and the condenser 5a. The oil separator 8 has an oil return port. 81. The oil return port 81 is connected to the compressor 1 through the oil return pipe 82. By setting the oil separator 8, the lubricating oil in the vapor of the high-pressure mixed refrigerant discharged from the compressor 1 can be separated, so as to improve the heat exchange effect of the refrigerant in the condenser 5a and the evaporator 5b.

As shown in FIG. 7 , the refrigeration system 300 further includes a first drying filter 9a, and the first drying filter 9a is disposed on the second connecting branch 3b and located between the liquid separator 2 and the first throttling device 6a. By arranging the first dry filter 9a, the first dry filter 9a can remove water and impurities in the high-temperature refrigerant in the second connecting branch 3b, so as to avoid water corrosion to the first throttle device 6a and other components , and at the same time, the blockage of the first throttling device 6a by impurities is avoided, thereby ensuring the normal operation of the refrigeration system 300 .

As shown in FIG. 7 , the refrigeration system 300 further includes a second drying filter 9b, which is disposed on the third connecting branch 3c and located between the liquid separator 2 and the second throttling device 6b. By arranging the second dry filter 9b, the second dry filter 9b can remove water and impurities in the low-temperature refrigerant in the third connection branch 3c, so as to avoid water corrosion to the second throttle device 6b and other components , and at the same time, the blockage of the second throttling device 6b by impurities is avoided, thereby ensuring the normal operation of the refrigeration system 300 .

Wherein, as shown in FIG. 7 , the second drying filter 9b may be disposed between the second heat exchanger 4b and the second throttling device 6b.

In a second aspect, an embodiment of the present invention provides a control method for the low-temperature storage device in the first aspect, including the following steps: as shown in FIG. 7 and FIG. 8 ;

S1. After the refrigeration system 300 starts to work, obtain the pressure value p in the fourth connecting branch 3d upstream of the control valve 7a;

Wherein, the main body performing this step S1 may be the pressure sensor 71;

S2. When the pressure value p is greater than or equal to the threshold value p ₀ , open the control valve 7a, so that at least a part of the refrigerant flowing out of the air outlet 23 of the liquid separator 2 flows into the expansion vessel 7b along the fourth connecting branch 3d.

Wherein, the main body performing this step S2 may be the controller 72 .

The technical problem solved and the technical effect obtained by the control method of the low-temperature storage device provided by the embodiment of the present invention are the same as the technical problem solved and the technical effect obtained by the low-temperature storage device in the first aspect, and are not repeated here.

For the features that are the same or similar to those in the product embodiments of the low-temperature storage device that appear in the control method embodiment of the low-temperature storage device, reference may be made to the description in the product embodiment of the low-temperature storage device, which will not be repeated here. .

In the description of this specification, the particular features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (9)

1. A low-temperature storage device, comprising: a box body, the box body is used to form a refrigeration space; a refrigeration system, the refrigeration system is used to cool the refrigeration space; It is characterized in that, the refrigeration system includes: a compressor, the compressor has a suction port and a discharge port; a liquid distributor, the liquid distributor has a liquid inlet, a liquid outlet and an air outlet, the liquid outlet is located at the bottom of the liquid distributor, and the air outlet is located at the top of the liquid distributor; a first connecting branch, one end of the first connecting branch is connected with the exhaust port, and the other end is connected with the liquid inlet; a condenser, which is arranged on the first connecting branch; a second connecting branch, one end of the second connecting branch is connected with the liquid outlet, and the other end is connected with the suction port; a first heat exchanger, the first heat exchanger has a first flow path and a second flow path capable of heat exchange, and the first flow path is arranged on the second connecting branch; a first throttling device, the first throttling device is arranged on the second connecting branch, and is located between the inlet end of the first flow path and the liquid separator; a third connecting branch, the first end of the third connecting branch is connected to the air outlet, and the second end is connected to the inlet end of the first flow path or the middle of the first flow path; the The second flow path is arranged on the third connecting branch; an evaporator, which is arranged on the third connecting branch and located on the downstream side of the second flow path; a second throttling device, the second throttling device is disposed on the third connecting branch, and is located between the second flow path and the evaporator; a fourth connection branch, one end of the fourth connection branch is connected with the air outlet, and the other end is connected with the air inlet; a control valve, which is arranged on the fourth connecting branch; an expansion vessel, the expansion vessel is connected to the fourth connection branch on the downstream side of the control valve; detection means configured to detect a pressure value in the fourth connection branch upstream of the control valve, and to open the control valve when the pressure value is greater than or equal to a threshold value, so that At least a part of the refrigerant flowing out of the air outlet flows into the expansion container along the fourth connection branch. 2. The cryogenic storage device according to claim 1, characterized in that, The detection device includes: a pressure sensor configured to detect the pressure value; a controller configured to open the control valve when the pressure value is greater than or equal to the threshold value, so that the refrigerant flowing out of the air outlet flows into the fourth connection branch to the in the expansion vessel. 3 . The low-temperature storage device according to claim 1 , wherein the refrigeration system further comprises a third throttling device, and the third throttling device is arranged on the fourth connecting branch and located on the The downstream side of the connection point of the expansion vessel and the fourth connection branch. The low-temperature storage device according to any one of claims 1 to 3, wherein the first heat exchanger is a sleeve heat exchanger, and the first heat exchanger comprises an inner tube and a sleeve an outer tube outside the inner tube; The first flow path is formed in the inner tube, and the second flow path is formed by the gap between the inner tube and the outer tube; Alternatively, the second flow path is formed in the inner pipe, and the first flow path is formed by the gap between the inner pipe and the outer pipe. 5 . The low-temperature storage device according to claim 1 , wherein the refrigeration system further comprises a second heat exchanger, the second heat exchanger having a third heat exchanger capable of heat exchange. 6 . a flow path and a fourth flow path; The third flow path and the fourth flow path are both arranged in the third connection branch, and the third flow path is located between the second flow path and the second throttle device, The fourth flow path is located between the evaporator and the first flow path. 6 . The low-temperature storage device according to claim 1 , wherein the refrigeration system further comprises a third heat exchanger, and the third heat exchanger has a fifth heat exchanger capable of heat exchange. 7 . flow path and sixth flow path; The fifth flow path is arranged on the first connecting branch, and is located between the condenser and the liquid separator; The sixth flow path is arranged on the second connecting branch, and is located between the first heat exchanger and the suction port. 7. The low-temperature storage device according to any one of claims 1 to 3, wherein The box body includes an outer shell, an inner container, and a heat insulating layer between the outer shell and the inner container, and the inner container is used to form the refrigeration space; The liner includes: a bottom wall and a top wall spaced apart along the height direction of the box body; two side walls spaced apart along the width direction of the box body; a rear wall at the rear side of the refrigerated space; The evaporator includes a heat exchange tube disposed on the top wall, the rear wall and the outer surfaces of the two side walls. 8. The cryogenic storage device according to any one of claims 1 to 3, wherein the refrigeration system further comprises at least one of an oil separator, a first drying filter, and a second drying filter; Wherein, the oil separator is arranged on the first connecting branch, and is located between the compressor and the condenser, and the oil separator has an oil return port, and the oil return port is connected to the oil return pipe through an oil return pipe. connected to the compressor; The first drying filter is arranged on the second connecting branch, and is located between the liquid separator and the first throttling device; The second drying filter is arranged on the third connecting branch, and is located between the liquid separator and the second throttling device. 9. A control method for the cryogenic storage device according to any one of claims 1 to 8, characterized in that it comprises the following steps: After the refrigeration system starts to work, obtain the pressure value in the fourth connecting branch upstream of the control valve; When the pressure value is greater than or equal to the threshold value, the control valve is opened, so that at least a part of the refrigerant flowing out of the air outlet of the liquid separator flows into the expansion container along the fourth connection branch.

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