A cooling device for stem cell storage

Abstract

The utility model discloses a cooling device for stem cell storage, including liquid nitrogen storage jar, the inside support subassembly of liquid nitrogen storage jar is provided with, the left side of liquid nitrogen storage jar is provided with cooling assembly, through programmable logic controller control liquid nitrogen generator work and make liquid nitrogen solenoid valve open, can make the liquid nitrogen generator of liquid nitrogen that manufactures through import pipe and flow into liquid nitrogen storage jar to stem cell storage test tube carries out low temperature cryopreservation, makes stem cell to be able to keep high activity under very low temperature, through pulling out the location pin and to the top seal cover is carried out and pulls, can stem cell storage test tube from liquid nitrogen storage jar pulls out and carries on taking and placing, and bottom sealing plate will carry out the plugging of the sealing jar cover through the blocking cavity to avoid staff in stem cell storage test tube taking and placing process, the liquid nitrogen in liquid nitrogen storage jar escapes to the outside upwards, to this guarantee staff stem cell storage test tube taking and placing convenience.

Description

Technical Field

[0001] This utility model relates to the field of stem cell storage technology, specifically a cooling device for stem cell storage. Background Technology

[0002] Stem cells are a type of cell with unlimited or immortal self-renewal capacity and can produce at least one type of highly differentiated daughter cells. In the process of storing test tubes containing stem cells, a cooling device is needed to cool the storage tank so that the test tubes containing stem cells can be stored at low temperatures.

[0003] In the prior art, a stem cell storage device with the publication number "CN214453562U" facilitates the storage and retrieval of stem cells through the cooperation of a mounting plate and a storage rack, effectively preventing frostbite caused by the user during retrieval, and effectively preventing the loss of cold air during the storage and retrieval of stem cells.

[0004] However, the above technical solutions and existing technologies have the following drawbacks:

[0005] Firstly, the storage device uses a refrigeration system to cool the cold storage compartment. However, compared to liquid nitrogen cryopreservation, this cooling method results in relatively low stem cell activity, and the recovery of cell activity after thawing is slower, thus the refrigeration effect is not good. Secondly, after the storage racks are pulled out, the staff needs to immediately put the lids back on the tanks; otherwise, the cold air inside the tanks will quickly escape. When removing multiple storage racks, the staff needs to repeatedly put the lids back on. Therefore, this method of removal is not convenient enough in actual use and its practicality is poor. Utility Model Content

[0006] The purpose of this invention is to provide a cooling device for stem cell storage to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A cooling device for stem cell storage includes a support substrate, a liquid nitrogen storage tank, a sealed lid, and stem cell storage tubes. The liquid nitrogen storage tank is fixedly connected to the right side of the upper end face of the support substrate. The sealed lid is installed on the upper end face of the liquid nitrogen storage tank. Multiple stem cell storage tubes are inserted into the liquid nitrogen storage tank. A support assembly is provided inside the liquid nitrogen storage tank, and the support assembly is used to extend the multiple stem cell storage tubes into the liquid nitrogen storage tank. A cooling assembly is provided on the left side of the liquid nitrogen storage tank, and the cooling assembly is used to cool the liquid nitrogen storage tank.

[0009] Preferably, the support assembly includes a limiting ring, a test tube support plate, a connecting rod, a top sealing cap, a bottom sealing plate, a bottom support, and a placement cavity. The bottom support is fixedly connected to the lower side of the liquid nitrogen storage tank. The bottom sealing plate is placed on the upper surface of the bottom support. The connecting rod is connected to the middle position of the upper surface of the bottom sealing plate. The test tube support plate is provided on the annular side of the connecting rod. The placement cavity is opened on the upper surface of the test tube support plate. The top sealing cap is connected to the upper end of the connecting rod. The limiting ring is fixedly connected to the upper surface of the sealed tank cover.

[0010] Preferably, the top sealing cover has a first positioning through hole inside, the connecting rod has a second positioning through hole on its lower side inside, and the limiting ring has a positioning pin inserted inside, and the positioning pin matches the first positioning through hole and the second positioning through hole respectively.

[0011] Preferably, the cooling assembly includes a cryogenic liquid level sensor, a liquid nitrogen solenoid valve, a liquid nitrogen generator, a support plate, legs, a control box, a programmable logic controller (PLC), and an inlet pipe. The inlet pipe is fixedly connected to the upper side of the left end face of the liquid nitrogen storage tank. The legs are fixedly connected to the left side of the upper end face of the support base plate. The support plate is fixedly connected to the upper end of the legs. The liquid nitrogen generator is mounted on the upper end face of the support plate. A liquid nitrogen solenoid valve is connected between the outlet end of the liquid nitrogen generator and the inlet end of the inlet pipe. The control box is fixedly connected to the left side of the upper end face of the support base plate. The PLC is installed inside the control box. The cryogenic liquid level sensor is mounted on the left side of the upper end face of the sealed tank cover.

[0012] Preferably, a first sealing inner liner ring is embedded in the annular side of the limiting ring, a blocking cavity is opened on the lower end face of the sealing can cover, and the blocking cavity matches the bottom sealing plate, and a second sealing inner liner ring is embedded in the annular side of the blocking cavity.

[0013] Preferably, the lower end face of the sealed tank cover is provided with a first heat insulation layer, and the annular side of the liquid nitrogen storage tank is provided with an external heat insulation sleeve.

[0014] Preferably, the upper end face of the top sealing cover is provided with a lifting handle, the lower end face of the top sealing cover is provided with a second heat insulation layer, and the inner diameter of the limiting ring is the same as the outer diameter of the top sealing cover.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] 1. By controlling the liquid nitrogen generator and opening the liquid nitrogen solenoid valve through a programmable logic controller (PLC), the liquid nitrogen generated by the generator flows into the liquid nitrogen storage tank through the inlet tube to cryopreserve stem cell storage tubes. This allows the stem cells to maintain high activity at extremely low temperatures. The PLC also monitors the liquid nitrogen level in the storage tank in real time through a cryogenic level sensor. When the liquid nitrogen level exceeds the preset maximum value, it controls the liquid nitrogen generator and the liquid nitrogen solenoid valve to close, preventing excessive liquid nitrogen in the storage tank. When the liquid nitrogen is consumed to the point where the level falls below the preset minimum value, it controls the liquid nitrogen generator to operate again and opens the liquid nitrogen solenoid valve to automatically replenish the liquid nitrogen in the storage tank, resulting in excellent refrigeration performance.

[0017] 2. By removing the positioning pin and lifting the top sealing cap, the top sealing cap, via the connecting rod, will lift the test tube support plate and the bottom sealing plate together, thus lifting the stem cell storage test tube from the liquid nitrogen storage tank for handling. By inserting the positioning pin into the second positioning through hole, the connecting rod can be locked in place, preventing it from falling back. The bottom sealing plate will block the sealing tank lid through the blocking cavity, and the second sealing inner liner ring will further improve the seal between the blocking cavity and the bottom sealing plate, thereby preventing liquid nitrogen in the liquid nitrogen storage tank from escaping to the outside during the handling of the stem cell storage test tube, ensuring the convenience of handling the stem cell storage test tube. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the main structure of this utility model;

[0019] Figure 2 This is a structural diagram showing the support component being lifted to the outside in this utility model;

[0020] Figure 3 This is a front cross-sectional view of the support component and the cooling component in this utility model;

[0021] Figure 4 This is a partial structural diagram of the support component in this utility model;

[0022] Figure 5 This is a circuit block diagram of the cooling component in this utility model.

[0023] In the diagram: 1. Supporting base plate; 2. Liquid nitrogen storage tank; 21. External insulation sleeve; 3. Sealed tank lid; 31. First insulation layer; 4. Support assembly; 41. Limiting ring; 42. Positioning pin; 43. Test tube support plate; 44. Connecting rod; 45. First positioning through hole; 46. Top sealing cap; 461. Lifting handle; 462. Second insulation layer; 47. First sealing inner ring; 48. Second sealing inner ring; 49. Second positioning through hole; 411. Bottom sealing plate; 412. Bottom support; 413. Placement cavity; 414. Blocking cavity; 5. Cooling assembly; 51. Low temperature liquid level sensor; 52. Liquid nitrogen solenoid valve; 53. Liquid nitrogen generator; 54. Support plate; 55. Support leg; 56. Control box; 57. Programmable logic controller; 58. Inlet tube; 6. Stem cell storage test tube. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] Please see Figures 1-5 This utility model provides a technical solution:

[0026] Example 1:

[0027] A cooling device for stem cell storage includes a support base plate 1, a liquid nitrogen storage tank 2, a sealing lid 3, and stem cell storage tubes 6. The liquid nitrogen storage tank 2 is fixedly connected to the upper right side of the support base plate 1. The liquid nitrogen storage tank 2 can store a certain amount of liquid nitrogen for cryopreserving multiple stem cell storage tubes 6 inserted inside. The sealing lid 3 is installed on the upper surface of the liquid nitrogen storage tank 2, sealing the opening at the upper end of the liquid nitrogen storage tank 2. The sealing lid 3 is detachable for easy cleaning and maintenance of the interior of the liquid nitrogen storage tank 2. Multiple stem cell storage tubes 6 are inserted inside the liquid nitrogen storage tank 2. The cell storage tube 6 is made of cryotube material, and the stem cell storage tube 6 made of cryotube material can store stem cells. The lower end face of the sealed lid 3 is provided with a first heat insulation layer 31, which is made of aerogel felt. The first heat insulation layer 31 made of aerogel felt reduces the thermal conductivity of the sealed lid 3, preventing external heat from being easily conducted to the liquid nitrogen storage tank 2 through the sealed lid 3. The annular side of the liquid nitrogen storage tank 2 is provided with an external heat insulation sleeve 21, which is made of heat insulation cotton. The external heat insulation sleeve 21 made of heat insulation cotton improves the heat insulation of the liquid nitrogen storage tank 2, preventing the low temperature in the liquid nitrogen storage tank 2 from rapidly escaping to the outside.

[0028] The liquid nitrogen storage tank 2 is equipped with a support component 4. The support component 4 can not only insert multiple stem cell storage tubes 6 into the liquid nitrogen storage tank 2, but also facilitate the staff to lift out the stem cell storage tubes 6 from the liquid nitrogen storage tank 2 for handling. The liquid nitrogen storage tank 2 is equipped with a cooling component 5 on the left side. The cooling component 5 is used to cool the liquid nitrogen storage tank 2 so that the liquid nitrogen storage tank 2 can freeze the stem cells.

[0029] Cooling assembly 5 includes a cryogenic liquid level sensor 51, a liquid nitrogen solenoid valve 52, a liquid nitrogen generator 53, a support plate 54, a support leg 55, a control box 56, a programmable logic controller 57, and an inlet pipe 58. An inlet pipe 58 is fixedly connected to the upper side of the left end face of the liquid nitrogen storage tank 2, allowing liquid nitrogen discharged from the liquid nitrogen solenoid valve 52 to be introduced into the liquid nitrogen storage tank 2. A support leg 55 is fixedly connected to the left side of the upper end face of the support base plate 1, and a support plate 54 is fixedly connected to the upper end of the support leg 55, providing support for the support plate 54. The support plate 54 is fixed to provide stable support for the liquid nitrogen generator 53. The liquid nitrogen generator 53 is installed on the upper surface of the support plate 54. When working, the liquid nitrogen generator 53 can produce cryogenic liquid nitrogen. A liquid nitrogen solenoid valve 52 is connected between the outlet end of the liquid nitrogen generator 53 and the inlet end of the inlet pipe 58. The liquid nitrogen solenoid valve 52 facilitates the programmable logic controller 57 to control the opening and closing of the inlet pipe 58. A control box 56 is fixedly connected to the left side of the upper surface of the support base plate 1. The control box 56 can store and protect the programmable logic controller 57.

[0030] The control box 56 houses a programmable logic controller (PLC) 57. The PLC 57 can store instructions for performing logical operations, sequential control, timing, counting, and arithmetic operations. It can not only receive and process data transmitted from the cryogenic level sensor 51, but also automatically control the operation of the liquid nitrogen solenoid valve 52 and the liquid nitrogen generator 53. A cryogenic level sensor 51 is installed on the left side of the upper surface of the sealed tank cover 3. The cryogenic level sensor 51 can measure the liquid nitrogen level in a cryogenic environment and transmit the measured data to the PLC 57 in real time. The electrical connections of the cryogenic level sensor 51, the liquid nitrogen solenoid valve 52, and the liquid nitrogen generator 53 are as follows: Figure 5 As already shown in the diagram, the internal detailed structure and working principle of the cryogenic liquid level sensor 51, the liquid nitrogen solenoid valve 52, and the liquid nitrogen generator 53 are all relatively mature technologies in the existing field, so they will not be described in detail here.

[0031] Example 2:

[0032] Based on Embodiment 1, in this embodiment, by removing the positioning pin 42 and lifting the top sealing cover 46, the top sealing cover 46 can be lifted together with the test tube support plate 43 and the bottom sealing plate 411 via the connecting rod 44, thereby lifting the stem cell storage test tube 6 out of the liquid nitrogen storage tank 2 for handling. By inserting the positioning pin 42 into the second positioning through hole 49, the connecting rod 44 can be locked in place, preventing it from falling back. The bottom sealing plate 411 will block the sealing tank cover 3 through the blocking cavity 414, and the second sealing inner liner ring 48 will improve the sealing between the blocking cavity 414 and the bottom sealing plate 411, thereby preventing liquid nitrogen in the liquid nitrogen storage tank 2 from escaping to the outside during the handling of the stem cell storage test tube 6, thus ensuring the convenience of handling the stem cell storage test tube 6.

[0033] The support assembly 4 includes a limiting ring 41, a test tube support plate 43, a connecting rod 44, a top sealing cap 46, a bottom sealing plate 411, a bottom support 412, and a placement cavity 413. The bottom support 412 is fixedly connected to the lower side of the liquid nitrogen storage tank 2. The bottom support 412 is connected to the liquid nitrogen storage tank 2, the control box 56, and the support leg 55 by welding. The bottom support 412 can support the liquid nitrogen storage tank 2, the control box 56, and the support leg 55 respectively. The bottom sealing plate 411 is placed on the upper surface of the bottom support 412. The bottom sealing plate 411 can not only support the connecting rod 44, but also seal the sealing tank cap 3 after moving up into the blocking cavity 414, so as to prevent the liquid nitrogen in the liquid nitrogen storage tank 2 from escaping during the process of lifting and placing the stem cell storage test tube 6.

[0034] A connecting rod 44 is connected to the middle of the upper surface of the bottom sealing plate 411. The connecting rod 44 is connected to the bottom sealing plate 411, the test tube support plate 43, and the top sealing cover 46 by welding. The connecting rod 44 not only supports the test tube support plate 43, but also facilitates the synchronous lifting and lowering of the bottom sealing plate 411 by the top sealing cover 46. The test tube support plate 43 is provided on the annular side of the connecting rod 44. The upper surface of the test tube support plate 43 has a placement cavity 413, which matches the bottom of the stem cell storage test tube 6. The upper surface of the test tube support plate 43 has a placement cavity 413. The test tube support plate 43 of cavity 413 can support and limit the stem cell storage test tube 6, preventing the stem cell storage test tube 6 from shaking and slipping during cryopreservation. The upper end of the connecting rod 44 is connected to the top sealing cap 46, which can seal the limiting ring 41. The upper end of the sealing container lid 3 is fixedly connected to the limiting ring 41. The limiting ring 41 and the sealing container lid 3 are an integral structure. The inner diameter of the limiting ring 41 is the same as the outer diameter of the top sealing cap 46. The limiting ring 41 can support the positioning pin 42 and the first sealing inner liner ring 47 respectively.

[0035] The top sealing cover 46 has a first positioning through hole 45 inside, and the connecting rod 44 has a second positioning through hole 49 on its lower side inside. A positioning pin 42 is inserted into the limiting ring 41, and the positioning pin 42 matches the first positioning through hole 45 and the second positioning through hole 49 respectively. The first positioning through hole 45 facilitates the positioning pin 42 in positioning the descending top sealing cover 46, and also facilitates the positioning pin 42 in positioning the ascending connecting rod 44. The inner annular side of the limiting ring 41... The first sealing inner ring 47 is embedded in the can. The first sealing inner ring 47 is made of polytetrafluoroethylene. The first sealing inner ring 47, made of polytetrafluoroethylene, not only improves the sealing performance between the top sealing cover 46 and the limiting ring 41, but also has good low temperature resistance. The lower end face of the sealing can cover 3 is provided with a blocking cavity 414, and the blocking cavity 414 matches the bottom sealing plate 411. The blocking cavity 414 can block and limit the rising bottom sealing plate 411, preventing the bottom sealing plate 411 from slipping upward.

[0036] A second sealing liner ring 48 is embedded in the annular side of the blocking cavity 414. The second sealing liner ring 48 is made of polytetrafluoroethylene (PTFE). The PTFE material of the second sealing liner ring 48 not only improves the sealing performance between the bottom sealing plate 411 and the blocking cavity 414, but also enhances its low-temperature resistance. A lifting handle 461 is provided on the upper surface of the top sealing cover 46. The lifting handle 461 and the top sealing cover 46 are an integral structure. The lifting handle 461 facilitates the operator to move the top sealing cover 46 up and down by hand. A second heat insulation layer 462 is provided on the lower surface of the top sealing cover 46. The second heat insulation layer 462 is made of aerogel felt. The aerogel felt material of the second heat insulation layer 462 reduces the thermal conductivity of the top sealing cover 46, preventing external heat from being easily conducted to the liquid nitrogen storage tank 2 through the top sealing cover 46.

[0037] Working principle: (Reference) Figure 1After the stem cell storage tube 6 is placed into the liquid nitrogen storage tank 2, the operator controls the liquid nitrogen generator 53 to operate and open the liquid nitrogen solenoid valve 52 via the programmable logic controller 57. At this time, the liquid nitrogen generated by the generator 53 flows into the liquid nitrogen storage tank 2 through the inlet pipe 58 to cool it down, thus cryopreserving the stem cell storage tube 6 in the tank 2. During this process, the cryogenic level sensor 51 monitors the liquid nitrogen level inside the tank 2 in real time. When the programmable logic controller 57... When the cryogenic liquid level sensor 51 detects that the liquid nitrogen level in the liquid nitrogen storage tank 2 has reached the preset maximum value, it will control the liquid nitrogen generator 53 and the liquid nitrogen solenoid valve 52 to close, so as to prevent excessive liquid nitrogen in the liquid nitrogen storage tank 2. When the liquid nitrogen in the liquid nitrogen storage tank 2 is consumed to the point that the liquid level is lower than the preset minimum value, the programmable logic controller 57 will control the liquid nitrogen generator 53 to work again and open the liquid nitrogen solenoid valve 52, so as to automatically replenish liquid nitrogen in the liquid nitrogen storage tank 2, so that the liquid nitrogen storage tank 2 can maintain the low temperature for cryopreservation of stem cell storage test tubes 6.

[0038] When it is necessary to remove the stem cell storage tube 6 from the liquid nitrogen storage tank 2, the operator first removes the positioning pin 42 and lifts the top sealing cover 46 using the lifting handle 461. This causes the top sealing cover 46 to rise along with the tube support plate 43 and the bottom sealing plate 411 via the connecting rod 44. The tube support plate 43 then lifts the stem cell storage tube 6, thus pulling the stem cell storage tube 6 out of the liquid nitrogen storage tank 2. During this process, when the bottom sealing plate 411 rises into the blocking cavity 414, the blocking cavity 414 will block the bottom sealing plate 411, preventing the top sealing cover 46 from moving further upward. Then, the positioning pin 42 is inserted into the second positioning through hole 49 to lock the connecting rod 44 in place (see reference). Figure 2 To prevent the connecting rod 44 from falling back, the staff can then remove the stem cell storage tube 6 from the test tube support plate 43. Simultaneously, the bottom sealing plate 411 seals the sealing tank lid 3 through the blocking cavity 414, and the second sealing inner ring 48 further improves the seal between the blocking cavity 414 and the bottom sealing plate 411. This prevents liquid nitrogen in the liquid nitrogen storage tank 2 from escaping upwards to the outside during the handling of the stem cell storage tube 6, reducing liquid nitrogen consumption and preventing frostbite from direct contact with liquid nitrogen. After the stem cell storage tube 6 is removed, simply pull out the positioning pin 42 again and quickly lower the top sealing cover 46 to re-insert the stem cell storage tube 6 into the liquid nitrogen storage tank 2 for continued freezing. Once the top sealing cover 46 is in place, insert the positioning pin 42 into the first positioning through hole 45 to lock the top sealing cover 46 (see reference). Figure 3 To prevent the top sealing cap 46 from loosening or shifting during use, the embedded first sealing inner ring 47 improves the sealing between the limiting ring 41 and the top sealing cap 46, so that the top sealing cap 46 can better seal the sealing can lid 3.

[0039] It should be noted that the circuits, electronic components, and driving devices involved in this utility model are all existing technologies, which can be fully implemented by those skilled in the art, and need not be elaborated upon. The content protected by this utility model does not involve improvements to the software and methods. At the same time, the power connection methods of each electrical device are existing mature technologies, which are well known to those skilled in the art, and will not be elaborated upon here.

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A cooling device for stem cell storage, comprising a support substrate (1), a liquid nitrogen storage tank (2), a sealed tank lid (3), and stem cell storage tubes (6), characterized in that: A liquid nitrogen storage tank (2) is fixedly connected to the right side of the upper end face of the support substrate (1). A sealed tank cover (3) is installed on the upper end face of the liquid nitrogen storage tank (2). Multiple stem cell storage tubes (6) are inserted inside the liquid nitrogen storage tank (2). A support component (4) is provided inside the liquid nitrogen storage tank (2), and the support component (4) is used to insert multiple stem cell storage tubes (6) into the liquid nitrogen storage tank (2). A cooling component (5) is provided on the left side of the liquid nitrogen storage tank (2), and the cooling component (5) is used to cool the liquid nitrogen storage tank (2).

2. The cooling device for stem cell storage according to claim 1, characterized in that: The support assembly (4) includes a limiting ring (41), a test tube support plate (43), a connecting rod (44), a top sealing cover (46), a bottom sealing plate (411), a bottom support (412), and a placement cavity (413). The bottom support (412) is fixedly connected to the lower side inside the liquid nitrogen storage tank (2). The bottom sealing plate (411) is placed on the upper surface of the bottom support (412). The connecting rod (44) is connected to the middle position of the upper surface of the bottom sealing plate (411). The test tube support plate (43) is provided on the annular side of the connecting rod (44). The placement cavity (413) is opened on the upper surface of the test tube support plate (43). The top sealing cover (46) is connected to the upper end of the connecting rod (44). The limiting ring (41) is fixedly connected to the upper surface of the sealed tank cover (3).

3. A cooling device for stem cell storage according to claim 2, characterized in that: The top sealing cover (46) has a first positioning through hole (45) inside, the connecting rod (44) has a second positioning through hole (49) on the lower side inside, and the limiting ring (41) has a positioning pin (42) inserted inside, and the positioning pin (42) matches the first positioning through hole (45) and the second positioning through hole (49) respectively.

4. A cooling device for stem cell storage according to claim 1, characterized in that: The cooling assembly (5) includes a cryogenic liquid level sensor (51), a liquid nitrogen solenoid valve (52), a liquid nitrogen generator (53), a support plate (54), a support leg (55), a control box (56), a programmable logic controller (57), and an inlet pipe (58). The inlet pipe (58) is fixedly connected to the upper side of the left end face of the liquid nitrogen storage tank (2). The support leg (55) is fixedly connected to the left side of the upper end face of the support base plate (1). The support plate (54) is fixedly connected to the upper end of the support leg (55). The liquid nitrogen generator (53) is installed on the upper end face of the support plate (54). The liquid nitrogen solenoid valve (52) is connected between the outlet end of the liquid nitrogen generator (53) and the inlet end of the inlet pipe (58). The control box (56) is fixedly connected to the left side of the upper end face of the support base plate (1). The programmable logic controller (57) is installed inside the control box (56). The cryogenic liquid level sensor (51) is installed on the left side of the upper end face of the sealed tank cover (3).

5. A cooling device for stem cell storage according to claim 2, characterized in that: The inner annular side of the limiting ring (41) is fitted with a first sealing inner liner ring (47), and the lower end face of the sealing can cover (3) is provided with a blocking cavity (414), and the blocking cavity (414) matches the bottom sealing plate (411). The inner annular side of the blocking cavity (414) is fitted with a second sealing inner liner ring (48).

6. A cooling device for stem cell storage according to claim 1, characterized in that: The lower end face of the sealed tank cover (3) is provided with a first heat insulation layer (31), and the annular side of the liquid nitrogen storage tank (2) is provided with an external heat insulation sleeve (21).

7. A cooling device for stem cell storage according to claim 2, characterized in that: The top sealing cover (46) is provided with a lifting handle (461) on its upper end face, and a second heat insulation layer (462) is provided on its lower end face. The inner diameter of the limiting ring (41) is the same as the outer diameter of the top sealing cover (46).

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