Liquid nitrogen tank

Abstract

The invention discloses a liquid nitrogen tank which comprises a liquid nitrogen tank body and further comprises a storage unit. And the adjusting unit comprises a main adjusting assembly which is rotationally arranged in the liquid nitrogen tank body and used for driving the storage unit away from the tank opening to integrally rotate, and a secondary adjusting assembly which is arranged in the main adjusting assembly and used for driving the storage unit close to the tank opening to locally rotate. When a sample is taken out of a liquid nitrogen tank body, if a storage unit corresponding to a target sample is far away from a tank opening, a main adjusting assembly is rotated firstly, so that the main adjusting assembly transfers the storage unit corresponding to the sample to the tank opening, and if the storage unit corresponding to the sample is located under the tank opening, the storage unit is directly pulled out through the tank opening; and if the storage unit corresponding to the sample deviates from the position under the tank opening, the secondary adjusting assembly is rotated, so that the storage unit corresponding to the sample is moved to the position under the tank opening, the other storage units are kept not rotating, and the situation that the samples in all the storage units are disordered in the repeated adjusting process is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of liquid nitrogen tank sampling, in particular to a liquid nitrogen tank. Background Art

[0002] Liquid nitrogen tanks are commonly used for low-temperature storage of biological samples, cells, tissues, and certain special materials. They maintain the activity and stability of the stored items through the low-temperature environment of liquid nitrogen. However, there are many problems with liquid nitrogen tanks in actual use that make sampling inconvenient.

[0003] The existing liquid nitrogen tank design has a relatively complex internal structure, and numerous sample storage racks and storage compartments are often submerged in liquid nitrogen. When a specific sample needs to be removed, it is usually necessary to rotate the rotating shaft used to drive the storage rack to switch positions so that the storage rack is moved to the opening of the liquid nitrogen tank, and then the storage rack is moved out of the liquid nitrogen tank. During this process, due to the liquid nitrogen covering the storage racks in the liquid nitrogen tank, it is difficult to accurately locate the target sample. In addition, the existing storage racks are fixed to the rotating shaft, resulting in the need to rotate and adjust all the storage racks in the liquid nitrogen tank when removing the sample corresponding to the liquid nitrogen tank opening. Due to the small opening of the liquid nitrogen tank, when rotating and removing the storage racks from the liquid nitrogen tank, the rotation angle of the storage rack to be removed is often too large or too small, causing the storage rack to deviate from the bottom of the tank opening. In order to smoothly remove the storage rack from the tank opening, it is necessary to repeatedly fine-tune the position of the storage rack by switching the rotation direction of the rotating shaft. The operation process is complicated, and repeatedly switching the rotation direction of the rotating shaft will cause further confusion among the samples in all the storage racks.

[0004] The above content is only used to assist in understanding the technical solution of the present invention and does not mean that the above content is the closest prior art. Summary of the Invention

[0005] The object of the present invention is to provide a liquid nitrogen tank to solve the problem of the prior art of removing samples from the liquid nitrogen tank mentioned in the background art, in which the target sample is difficult to be accurately located due to the covering of the storage rack by the liquid nitrogen, and the storage rack needs to be repeatedly switched in the rotation direction of the rotating shaft when removing the storage rack from the opening of the liquid nitrogen tank, causing confusion among all the samples in the storage rack.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A liquid nitrogen tank, comprising a liquid nitrogen tank body, and further comprising:

[0008] A storage unit is provided inside the liquid nitrogen tank body for storing samples;

[0009] The regulating unit includes a main regulating component which is rotatably arranged inside the liquid nitrogen tank body and is used to drive the storage unit away from the tank opening to rotate as a whole, and a secondary regulating component which is arranged inside the main regulating component and is used to drive the storage unit close to the tank opening to rotate partially.

[0010] Furthermore, the main adjustment component includes:

[0011] A main rotating shaft is rotatably connected to the interior of the liquid nitrogen tank body and is coaxial with the liquid nitrogen tank body;

[0012] A main rotating rod, fixedly connected to the upper end of the main rotating shaft, for adjusting the rotation of the main rotating shaft;

[0013] The clamping mechanism is arranged at the upper end of the liquid nitrogen tank body and is used to clamp the main shaft.

[0014] Furthermore, the clamping mechanism includes:

[0015] A fixed block is fixedly connected to the upper end of the liquid nitrogen tank body, and a retreat groove is formed on the upper end of the fixed block;

[0016] A slider, slidably inserted into the retreat groove;

[0017] A clamping shaft is fixedly connected to one end of the slider, and a hole for guiding the movement of the clamping shaft is provided inside the fixing block and outside the clamping shaft;

[0018] The jack is arranged at an equal angle on the outside of the main shaft and is used to cooperate with the clamping shaft to lock the main shaft.

[0019] Furthermore, the secondary adjustment component includes:

[0020] A secondary rotating shaft is provided in multiple groups and is rotatably connected to the inside of the main rotating shaft, and the secondary rotating shaft corresponds to the storage unit one by one;

[0021] A secondary rotating rod, fixedly connected to the upper end of the secondary rotating shaft, for adjusting the rotation of the secondary rotating shaft;

[0022] a gear fixedly connected to the lower end of the secondary shaft and located inside the main shaft;

[0023] There are multiple sets of arc-shaped racks, which are slidably arranged inside the main shaft. The side of the arc-shaped rack with teeth is engaged with the gear. The main shaft is provided with a guide groove for accommodating the arc-shaped rack and the gear;

[0024] A limiting mechanism, provided on the outside of the main shaft, for limiting the rotation of the arc-shaped rack;

[0025] an extension rod fixedly connected to a side of the arc-shaped rack opposite to the gear;

[0026] The vertical rod is fixedly connected to one end of the extension rod opposite to the arc-shaped rack and is used to limit the storage unit.

[0027] Furthermore, the limiting mechanism includes:

[0028] A support ring, fixedly sleeved on the outside of the main shaft and located below the extension rod;

[0029] Arc grooves, multiple groups of which are provided inside the support ring, and the arc grooves correspond one to one with the extension rods. The lower end of the extension rod is fixedly connected to a guide shaft, and the guide shaft extends into the arc groove and is used to cooperate with the guide groove to limit the movement of the arc rack;

[0030] A limiting ring is fixedly mounted on the outside of the main shaft and located at the upper end of the support ring. The horizontal plane where the upper end of the limiting ring is located is higher than the horizontal plane where the lower end of the arc-shaped rack is located. It is used to limit and guide one side of the arc-shaped rack relative to the gear. The curvature of the limiting ring is adapted to the curvature of the arc-shaped rack.

[0031] Furthermore, the storage unit includes:

[0032] A lifting block, one side of which is provided with multiple groups of storage slots at equal intervals from top to bottom for storing samples;

[0033] A clamping sleeve is fixedly connected to one side of the lifting block, and the clamping sleeve is slidably sleeved on the outer side of the vertical rod;

[0034] A lifting block is fixedly connected to the upper end of the lifting block and is used for taking the lifting block.

[0035] Furthermore, the height of the upper end of the lifting block is close to the height of the tank mouth;

[0036] The height of the upper end of the vertical rod is close to the height of the tank mouth.

[0037] Furthermore, a plurality of first marking blocks are provided on the upper end of the main shaft, and the first marking blocks correspond one to one with the lifting blocks, and are used to digitally mark the corresponding lifting blocks;

[0038] One side of the lifting block is provided with a second marking block corresponding to the storage slots one by one, and is used to mark the types of samples in the storage slots.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention is that when taking out a sample from a liquid nitrogen tank body, if the storage unit corresponding to the target sample is far away from the tank opening, the main adjustment component is first rotated so that the main adjustment component transfers the storage unit corresponding to the sample to the tank opening. If the storage unit corresponding to the sample is located directly below the tank opening, it is directly pulled out through the tank opening. If the storage unit corresponding to the sample is offset from being directly below the tank opening, the secondary adjustment component is rotated so that the storage unit corresponding to the sample is moved directly below the tank opening, while the remaining storage units remain unchanged, thereby avoiding confusion of the samples in all the storage units during the repeated adjustment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0042] Figure 2 This is a schematic diagram of the internal structure of the liquid nitrogen tank body of the present invention;

[0043] Figure 3 This is a schematic structural diagram of the clamping mechanism of the present invention;

[0044] Figure 4 This is a schematic diagram of the storage unit structure of the present invention;

[0045] Figure 5 This is a schematic structural diagram of the main regulating assembly of the present invention;

[0046] Figure 6 For the present invention Figure 5 Enlarged view of point A in the middle;

[0047] Figure 7 This is a schematic diagram of the process of removing the storage unit from the tank mouth of the present invention.

[0048] Reference numerals: 100, liquid nitrogen tank body; 1001, tank mouth; 1002, limiting groove; 101, tank cover; 1, adjustment unit; 11, main adjustment assembly; 111, main rotating shaft; 1111, insertion hole; 1112, guide groove; 1113, limiting plate; 1114, receiving hole; 112, main rotating rod; 113, clamping mechanism; 1131, fixing block; 1132, retreat groove; 1133, slider; 1134, clamping shaft; 114 , first marking block; 12, secondary adjustment assembly; 121, secondary rotating shaft; 122, secondary rotating rod; 123, gear; 124, limiting mechanism; 1241, supporting ring; 1242, arc groove; 1243, limiting ring; 125, arc rack; 126, extension rod; 1261, guide shaft; 127, vertical pole; 2, storage unit; 21, lifting block; 22, storage slot; 23, ferrule; 24, lifting block; 25, second marking block. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] See also Figure 1-7 , the present invention provides a technical solution:

[0051] A liquid nitrogen tank includes a liquid nitrogen tank body 100 and further includes:

[0052] The storage unit 2 is provided inside the liquid nitrogen tank body 100 and is used to store samples;

[0053] The adjustment unit 1 includes a main adjustment component 11 that is rotatably arranged inside the liquid nitrogen tank body 100 and is used to drive the storage unit 2 away from the tank opening 1001 to rotate as a whole, and a secondary adjustment component 12 that is arranged inside the main adjustment component 11 and is used to drive the storage unit 2 close to the tank opening 1001 to rotate locally.

[0054] It should be noted that: when it is necessary to take out a sample from the liquid nitrogen tank body 100, if the storage unit 2 corresponding to the target sample is away from the tank mouth 1001, the main adjustment component 11 is rotated first so that the main adjustment component 11 transfers the storage unit 2 corresponding to the sample to the tank mouth 1001. If the storage unit 2 corresponding to the sample is located directly below the tank mouth 1001, it is directly pulled out through the tank mouth 1001. If the storage unit 2 corresponding to the sample is offset from being directly below the tank mouth 1001, the secondary adjustment component 12 is rotated so that the storage unit 2 corresponding to the sample is moved directly below the tank mouth 1001, while the remaining storage units 2 remain unchanged, so as to avoid confusion among the samples in all the storage units 2 during the repeated adjustment process.

[0055] As an improvement, Figure 1-3 As shown, the main adjustment component 11 includes:

[0056] A main rotating shaft 111 is rotatably connected to the interior of the liquid nitrogen tank body 100 and is coaxial with the liquid nitrogen tank body 100;

[0057] A main rotating rod 112 is fixedly connected to the upper end of the main rotating shaft 111 and is used to adjust the rotation of the main rotating shaft 111;

[0058] The clamping mechanism 113 is provided at the upper end of the liquid nitrogen tank body 100 and is used to clamp the main shaft 111 .

[0059] Further, such as Figure 3 As shown, the clamping mechanism 113 includes:

[0060] A fixing block 1131 is fixedly connected to the upper end of the liquid nitrogen tank body 100 , and a retreat groove 1132 is formed on the upper end of the fixing block 1131 ;

[0061] The slider 1133 is slidably inserted into the retreat groove 1132;

[0062] The clamping shaft 1134 is fixedly connected to one end of the slider 1133 . A hole for guiding the movement of the clamping shaft 1134 is provided inside the fixing block 1131 and outside the clamping shaft 1134 .

[0063] The insertion hole 1111 is provided at an equal angle to the outside of the main shaft 111 and is used to cooperate with the clamping shaft 1134 to lock the main shaft 111;

[0064] The lower end of the main rotating shaft 111 is fixedly connected to a limiting plate 1113. The diameter of the limiting plate 1113 is larger than the diameter of the main rotating shaft 111 and is used to limit the main rotating shaft 111. The limiting plate 1113 is rotatably connected to the bottom of the liquid nitrogen tank body 100. A limiting groove 1002 for accommodating the limiting plate 1113 is provided inside the liquid nitrogen tank body 100 and on the outside of the limiting plate 1113.

[0065] As an improvement, Figure 5-6 As shown, the secondary adjustment component 12 includes:

[0066] The secondary rotating shafts 121 are provided in multiple groups and are rotatably connected to the inside of the main rotating shaft 111. The secondary rotating shafts 121 correspond to the storage units 2 one by one;

[0067] An accommodating hole 1114 for accommodating the secondary rotating shaft 121 is provided inside the main rotating shaft 111 and outside the secondary rotating shaft 121;

[0068] A secondary rotating rod 122 is fixedly connected to the upper end of the secondary rotating shaft 121 and is used to adjust the rotation of the secondary rotating shaft 121;

[0069] The gear 123 is fixedly connected to the lower end of the secondary shaft 121 and is located inside the main shaft 111;

[0070] There are multiple sets of arc-shaped racks 125 and they are slidably arranged inside the main shaft 111. The side of the arc-shaped rack 125 with teeth is engaged with the gear 123. The main shaft 111 is provided with a guide groove 1112 for accommodating the arc-shaped rack 125 and the gear 123.

[0071] A limiting mechanism 124 is provided on the outside of the main shaft 111 and is used to limit the rotation of the arc-shaped rack 125;

[0072] An extension rod 126 is fixedly connected to a side of the arc-shaped rack 125 opposite to the gear 123;

[0073] The vertical rod 127 is fixedly connected to one end of the extension rod 126 opposite to the arc-shaped rack 125 and is used to limit the storage unit 2.

[0074] Further, such as Figure 5-6 As shown, the limiting mechanism 124 includes:

[0075] A support ring 1241 is fixedly mounted on the outside of the main shaft 111 and below the extension rod 126;

[0076] Multiple groups of arcuate grooves 1242 are provided inside the support ring 1241. The arcuate grooves 1242 correspond one-to-one to the extension rods 126. The lower end of the extension rod 126 is fixedly connected to a guide shaft 1261. The guide shaft 1261 extends into the arcuate groove 1242 and is used to cooperate with the guide groove 1112 to limit the movement of the arcuate rack 125.

[0077] The limiting ring 1243 is fixedly mounted on the outside of the main shaft 111 and is located at the upper end of the support ring 1241. The horizontal plane where the upper end of the limiting ring 1243 is located is higher than the horizontal plane where the lower end of the arc-shaped rack 125 is located. It is used to limit and guide one side of the arc-shaped rack 125 relative to the gear 123. The curvature of the limiting ring 1243 is adapted to the curvature of the arc-shaped rack 125.

[0078] Furthermore, Figure 4 , Figure 7 As shown, the storage unit 2 includes:

[0079] A lifting block 21, one side of which is provided with multiple groups of storage slots 22 at equal intervals from top to bottom for storing samples;

[0080] A clamping sleeve 23 is fixedly connected to one side of the lifting block 21, and the clamping sleeve 23 is slidably sleeved on the outside of the vertical rod 127;

[0081] A lifting block 24 is fixedly connected to the upper end of the lifting block 21 and is used to take the lifting block 21;

[0082] It should be supplemented that the storage slot 22 can be used to directly place samples therein, or a drawer containing samples can be inserted into the storage slot 22 .

[0083] Among them, Figure 2 , Figure 7 As shown, the height of the upper end of the lifting block 24 is close to the height of the tank mouth 1001;

[0084] The height of the upper end of the vertical rod 127 is close to the height of the tank mouth 1001;

[0085] The tank mouth 1001 is inserted into the tank cover 101 for sealing the interior of the liquid nitrogen tank body 100 .

[0086] In addition, a plurality of first marking blocks 114 are provided on the upper end of the main shaft 111. The first marking blocks 114 correspond to the lifting blocks 21 one by one and are used to number the corresponding lifting blocks 21.

[0087] A second marking block 25 corresponding to each storage slot 22 is provided on one side of the lifting block 21 for marking the type of sample in the storage slot 22 .

[0088] It should be noted that if Figure 2 , Figure 4 , Figure 7 As shown, the first marking block 114 in the present invention is marked with Arabic numerals, and a query directory is attached to the upper end of the liquid nitrogen tank body 100. The query directory records the type of sample stored in the lifting block 21 corresponding to each first marking block 114, and also records the name of the sample corresponding to the second marking block 25 on one side of each storage slot 22 of each lifting block 21. When the sample is taken out from the liquid nitrogen tank body 100, the type of the sample is first searched in the query directory to determine the Arabic numeral label corresponding to the specific first marking block where the sample is located, and then the Arabic numeral label is used to find the layer number of the corresponding second marking block 25. In this way, the target sample can be quickly found and taken out from the liquid nitrogen tank body 100.

[0089] It should be noted that: in the specific implementation process of the present invention, Figure 2-4 As shown, initially, one end of the clamping shaft 1134 is inserted into the insertion hole 1111, so that the main rotating shaft 111 is locked. When the target sample needs to be taken out from the liquid nitrogen tank body 100, the first marking block 114 and the second marking block 25 corresponding to the target sample are found respectively;

[0090] like Figure 2-4As shown, if the lifting block 21 where the target sample is located is away from the tank mouth 1001, the slider 1133 is pulled to move along the retreat groove 1132, so that the card shaft 1134 is disengaged from the socket 1111, and the main rotating rod 112 is rotated. The main rotating rod 112 drives all the extension rods 126 to rotate synchronously through the main rotating shaft 111, and the extension rod 126 drives the lifting block 21 to rotate to the bottom of the opening of the tank mouth 1001 through the vertical rod 127. In this process, the position of the lifting block 21 inside the liquid nitrogen tank body 100 relative to the tank mouth 1001 is judged by observing the position of the first marking block 114 corresponding to the lifting block 21 for storing the target sample relative to the tank mouth 1001. 1001, then, open the tank cover 101, pull the lifting block 24 upward by hand, and the lifting block 24 drives the card sleeve 23 to move upward along the vertical rod 127 through the lifting block 21, so that the storage tank 22 containing the target sample is taken out from the tank mouth 1001. At this time, check the second marking block 25 to determine the storage tank 22 where the target sample is located. Then, take the target sample out of the storage tank 22, and lower the lifting block 24 into the liquid nitrogen tank body 100, and cover the tank cover 101, so as to overcome the covering of the liquid nitrogen on the storage tank 22, and can quickly and accurately take the target sample out of the liquid nitrogen tank body 100;

[0091] like Figure 5-7 As shown, if the lifting block 21 where the target sample is located is close to the bottom of the tank mouth 1001 at the beginning or the lifting block 21 deviates from the bottom of the tank mouth 1001 during the process of rotating to the main shaft 111, the clamping shaft 1134 is inserted into the insertion hole 1111 so that the main shaft 111 is positioned, and the secondary rotating rod 122 corresponding to the tank mouth 1001 is rotated. The secondary rotating rod 122 drives the gear 123 to rotate through the secondary rotating shaft 121, and the gear 123 drives the arc-shaped rack 125 to rotate along the limit ring 1243. The arc-shaped rack 125 rotates along the limit ring 1243. The extension rod 126 drives the vertical rod 127 to rotate, and the vertical rod 127 drives the lifting block 21 to be fine-tuned to the bottom of the tank mouth 1001 through the clamping sleeve 23, and then the lifting block 21 is taken out from the tank mouth 1001, so that only the lifting block 21 near the tank mouth 1001 needs to be adjusted in position separately, and there is no need to switch the rotation direction of all the lifting blocks 21 through the main rotating shaft 111, so as to avoid the samples in the storage slots 22 corresponding to all the lifting blocks 21 from being offset and confused due to the inertia of the samples themselves during the rotation adjustment.

[0092] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0093] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A liquid nitrogen tank, comprising a liquid nitrogen tank body (100), characterized in that: Also includes: A storage unit (2) is provided inside the liquid nitrogen tank body (100) and is used for storing samples; The regulating unit (1) comprises a main regulating assembly (11) rotatably arranged inside a liquid nitrogen tank body (100) for driving a storage unit (2) away from a tank opening (1001) to rotate as a whole, and a secondary regulating assembly (12) arranged inside the main regulating assembly (11) for driving a storage unit (2) close to the tank opening (1001) to rotate partially.

2. A liquid nitrogen tank according to claim 1, characterized in that: The main regulating assembly (11) comprises: A main rotating shaft (111) is rotatably connected to the interior of the liquid nitrogen tank body (100) and is coaxial with the liquid nitrogen tank body (100); A main rotating rod (112) is fixedly connected to the upper end of the main rotating shaft (111) and is used for rotating and adjusting the main rotating shaft (111); The clamping mechanism (113) is provided at the upper end of the liquid nitrogen tank body (100) and is used for clamping the main rotating shaft (111).

3. A liquid nitrogen tank according to claim 2, characterized in that: The clamping mechanism (113) comprises: A fixed block (1131) is fixedly connected to the upper end of the liquid nitrogen tank body (100), and a retreat groove (1132) is provided on the upper end of the fixed block (1131); A slider (1133) is slidably inserted into the retreat groove (1132); A clamping shaft (1134) is fixedly connected to one end of the slider (1133); a hole for guiding the movement of the clamping shaft (1134) is provided inside the fixed block (1131) and outside the clamping shaft (1134); The insertion hole (1111) is arranged at an equal angle on the outside of the main rotating shaft (111) and is used to cooperate with the clamping shaft (1134) to lock the main rotating shaft (111).

4. A liquid nitrogen tank according to claim 2, characterized in that: The secondary adjustment component (12) comprises: Secondary rotating shafts (121) are provided in multiple groups and are rotatably connected to the interior of the main rotating shaft (111), and the secondary rotating shafts (121) correspond one to one to the storage units (2); A secondary rotating rod (122) is fixedly connected to the upper end of the secondary rotating shaft (121) and is used for rotating and adjusting the secondary rotating shaft (121); a gear (123) fixedly connected to the lower end of the secondary rotating shaft (121) and located inside the main rotating shaft (111); A plurality of arc-shaped racks (125) are provided and are slidably arranged inside the main rotating shaft (111); a toothed side of the arc-shaped racks (125) is engaged with the gear (123); and a guide groove (1112) for accommodating the arc-shaped racks (125) and the gear (123) is provided inside the main rotating shaft (111); A limiting mechanism (124) is provided outside the main shaft (111) and is used to limit the rotation of the arc-shaped rack (125); an extension rod (126) fixedly connected to a side of the arc-shaped rack (125) opposite to the gear (123); The vertical rod (127) is fixedly connected to one end of the extension rod (126) opposite to the arc-shaped rack (125) and is used to limit the storage unit (2).

5. A liquid nitrogen tank according to claim 4, characterized in that: The limiting mechanism (124) includes: A support ring (1241) is fixedly sleeved on the outside of the main shaft (111) and located below the extension rod (126); A plurality of arc-shaped grooves (1242) are provided inside the support ring (1241), the arc-shaped grooves (1242) corresponding one to the extension rods (126), the lower end of the extension rods (126) being fixedly connected with a guide shaft (1261), the guide shaft (1261) extending into the arc-shaped grooves (1242) and used to cooperate with the guide grooves (1112) to limit the movement of the arc-shaped rack (125); A limiting ring (1243) is fixedly sleeved on the outside of the main rotating shaft (111) and located at the upper end of the supporting ring (1241); the horizontal plane where the upper end of the limiting ring (1243) is located is higher than the horizontal plane where the lower end of the arc-shaped rack (125) is located, and is used to limit and guide one side of the arc-shaped rack (125) relative to the gear (123); the curvature of the limiting ring (1243) is adapted to the curvature of the arc-shaped rack (125).

6. A liquid nitrogen tank according to claim 4, characterized in that: The storage unit (2) comprises: A lifting block (21), wherein a plurality of storage slots (22) are provided on one side of the lifting block (21) at equal intervals from top to bottom for storing samples; A clamping sleeve (23) is fixedly connected to one side of the lifting block (21), and the clamping sleeve (23) is slidably sleeved on the outside of the vertical rod (127) in an upward and downward manner; A lifting block (24) is fixedly connected to the upper end of the lifting block (21) and is used for taking the lifting block (21).

7. A liquid nitrogen tank according to claim 6, characterized in that: The height of the upper end of the lifting block (24) is close to the height of the tank mouth (1001); The height of the upper end of the vertical rod (127) is close to the height of the tank mouth (1001).

8. The liquid nitrogen tank according to claim 6, characterized in that: A plurality of first marking blocks (114) are provided at the upper end of the main rotating shaft (111), wherein the first marking blocks (114) correspond to the lifting blocks (21) one by one and are used to digitally mark the corresponding lifting blocks (21); A second marking block (25) corresponding one to one with the storage slot (22) is provided on one side of the lifting block (21) and is used to mark the type of sample in the storage slot (22).

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