Stem cell long-acting low-temperature refrigerator and cryopreservation method

Abstract

The invention discloses a stem cell long-acting low-temperature refrigerator and a cryopreservation method, and belongs to the technical field of cell freezing mechanisms and preservation methods, the stem cell long-acting low-temperature refrigerator comprises a freezing box, a refrigerator matched with the freezing box is installed on the freezing box, and a refrigeration opening extending into the freezing box is formed in the refrigerator; and the dehumidifying and cleaning mechanism comprises a double-shaft motor fixed to the inner wall of the freezing box, the output end of the double-shaft motor is connected to a driving wheel, the driving wheel and a driven wheel are in transmission connection through a conveying belt, and one end of the driving wheel penetrates through the cover body and extends to a fixing block provided with a convex notch. The technical problems that the humidity in the box body is relatively high, an ice crystal phenomenon can be generated in the cooling and freezing process, a dry environment for stem cells is not facilitated, and meanwhile, a solidification phenomenon can be possibly generated between a bag body outside the stem cells and a panel, so that subsequent taking-out work is not facilitated are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of cell freezing mechanisms and preservation methods, and in particular relates to a long-term low-temperature freezer for stem cells and a cryopreservation method. Background Art

[0002] Stem cells are a type of cell with unlimited or immortal self-renewal ability, capable of producing at least one type of highly differentiated daughter cells. Generally speaking, there is an intermediate progenitor cell population called "committed progenitor cells" between stem cells and their terminally differentiated daughter cells, which have limited expansion capacity and restricted differentiation potential. The function of these cell populations is to increase the number of differentiated cells produced after each division of stem cells.

[0003] Stem cell cryopreservation is a technology that places cells in a low-temperature environment to reduce cell metabolism for long-term storage. In existing cryopreservation technology, if the humidity in the box is high, ice crystals will be generated during the cooling and freezing process. On the one hand, it is not conducive to maintaining a dry environment for stem cells. On the other hand, during the crystallization process, the bag outside the stem cells may solidify between the panel, which is not conducive to subsequent removal work. In addition, the existing dehumidifier design cost is relatively high. It uses fan evaporation dehumidification and requires an independent ventilation hole shielding mechanism to open or close it, which consumes a lot of energy and is not conducive to cost reduction and environmental protection. Summary of the invention

[0004] The purpose of the present invention is to provide a long-term low-temperature freezer and a freezing preservation method for stem cells to solve the technical problem that the humidity in the box is high, ice crystals will be generated during the cooling and freezing process, which is not conducive to maintaining a dry environment for stem cells. At the same time, the bag body outside the stem cells may solidify between the panel, which is not conducive to the subsequent removal work.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] Stem cell long-term cryogenic freezer, including:

[0007] A freezer box, wherein a refrigerator adapted thereto is installed on the freezer box, and a refrigeration port extending to the interior of the freezer box is provided on the refrigerator;

[0008] A dehumidification cleaning mechanism, the dehumidification cleaning mechanism comprises a double-shaft motor fixed on the inner wall of the freezer, one output end of the double-shaft motor is connected to the driving wheel, and the other end is connected to the first reciprocating screw, the driving wheel and the driven wheel are connected by a conveyor belt transmission, one end of the driving wheel passes through the cover and extends to a fixed block with a convex notch;

[0009] Among them, one end of the driven wheel is fixedly connected to a first bevel gear, the outer wall of the first bevel gear is meshed and driven with a second bevel gear fixed on a second reciprocating screw, the second reciprocating screw is spirally driven with a first slider, the first slider and the baffle plate are fixedly connected by a cross beam, a ventilation hole is provided on the outer wall of the freezer under the baffle plate, and the fixed block and the ventilation hole are connected by a cleaning assembly.

[0010] Furthermore, the cleaning assembly includes a filter that is detachably installed at the ventilation hole, a scraper is installed on one end of the filter close to the outer wall of the freezer, and a blade is connected to the other end, the scraper and the blade are distributed in a circular array, and the central axis of the scraper passes through the filter and extends to the blade, one end of the central axis is connected to a push block through a compression spring, the top of the push block is integrally connected to a first inclined plate that can be inserted into the convex groove, and a second inclined plate fixed on the shielding plate is provided directly above the first inclined plate.

[0011] Furthermore, both the first inclined plate and the second inclined plate are arranged with their openings inclined outward, and their inclined parts are kept parallel. Both ends of the second inclined plate are connected to guide wheels through sliding parts, and both sides of the top of the outer wall of the push block are provided with slopes connected to the guide wheels.

[0012] Furthermore, the sliding member includes a central rotating tooth placed in the inner groove of the second inclined plate, and the upper and lower ends of the central rotating tooth are engaged with gear plates that move in the opposite direction. The gear plates at both ends are L-shaped, and the extension of one end of the gear plate is connected to a guide wheel through a bearing.

[0013] Furthermore, one end of the gear plate is connected with a strip groove along the length direction of the inner wall of the second inclined plate, and the edge of the outer wall of the guide wheel is provided with a rolling groove placed on the bearing. As the dual-axis motor is started, the crossbeam drives the baffle plate to open the ventilation hole, and at the same time the second inclined plate moves upward, and the push block is inserted into the convex groove under the elastic recovery action of the compression spring, and drives the blades and scrapers to rotate synchronously.

[0014] Furthermore, it also includes a pressing mechanism, which includes a second slider that is spirally driven and placed on the first reciprocating screw, and a pressure roller is movably connected to the downward extension of the second slider. A support plate placed inside the freezer is provided below the pressure roller, and a slide groove connected to the second slider is provided on the support plate, and the pressure rollers are connected by a synchronization rod.

[0015] Furthermore, telescopic rods are installed at diagonal positions on one side of the outer wall of the support plate, and the telescopic rods are connected to the side wall of the freezer by plugging, and the support plates are kept parallel.

[0016] A method for long-term cryopreservation of stem cells comprises the following steps:

[0017] S1.1. Place the bag containing stem cells on the support plate of the freezer, start the dual-axis motor, and under the action of mechanical transmission, move the shielding plate upward and open the vent hole. At this time, the compression spring moves toward the inside of the freezer under elastic recovery and is inserted into the convex notch of the fixed block;

[0018] S1.2. The driving wheel drives the central shaft to rotate, and drives the blades and scrapers on the filter to rotate at the same time. The rotation of the blades can accelerate the air flow, thereby accelerating the evaporation and dehumidification of water. Together with the blades, the scrapers can effectively remove the particulate impurities on the filter;

[0019] S1.3. After the dual-axis motor of step S1.1 is started, it can drive the rotation of the first reciprocating screw. Under the action of the spiral transmission, the second slider drives the pressing roller to press the bag body to ensure the flatness of the bag body. Finally, the refrigerator is turned on to cool the inside of the freezer through the compressor refrigeration technology.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] (1) A refrigerator is set up to discharge cold air into a freezer through compressor refrigeration technology, and the low-pressure gas is raised to high-pressure gas through the compressor, thereby realizing the refrigeration cycle process, which can effectively realize the cryopreservation of stem cells.

[0022] (2) A dehumidification and cleaning mechanism is provided. After the dual-axis motor is started, it can drive the rotation of the driving wheel and drive the rotation of the driven wheel through the conveyor belt. Through the meshing transmission of the gears, the horizontal rotation force can be converted into the vertical rotation force. With the help of the spiral transmission, the baffle plate can move upward and open the ventilation hole. At this time, the compression spring can insert the push block into the convex groove of the fixed block under the elastic recovery action, so that the driving wheel can drive the central shaft to rotate synchronously. During the rotation of the central shaft, the scraper and the blades can be driven to rotate. In this way, on the one hand, the dehumidification work inside the freezer can be realized, and on the other hand, the impurities on the filter can be removed. Moreover, the filter itself can further keep the ventilation hole clean, thereby ensuring the normal operation of the device and facilitating effective dehumidification and cleaning work.

[0023] (3) A cleaning component and a sliding member are provided. When the shielding plate moves downward, the ventilation hole is closed. The second inclined plate is inserted into the gap between the first inclined plate and the fixed block, so that the first inclined plate drives the pushing block to move outward. The guide wheels at both ends of the sliding member can prevent the pushing block from deviating from its position during movement. Moreover, the movement is carried out by rolling friction, which can reduce the friction damage between the structural parts and improve the service life of the device. At the same time, the guide wheel is connected with a center gear through a gear plate, which can ensure the synchronization of the centering movement of the guide wheel and further ensure the accuracy of the movement of the guide member.

[0024] (4) A pressing mechanism is provided. After the dual-axis motor is started, it can drive the rotation of the first reciprocating screw. Under the action of the spiral transmission, the pressing roller on the second slider can press the surface of the bag body, so that the bag body can ensure a certain degree of flatness and prevent wrinkles, which is not conducive to the cryopreservation of stem cells. At the same time, the support plate is connected to the freezer by telescopic plug-in, which can achieve rapid installation, facilitate personnel operation, and improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the structure of the long-term low-temperature freezer for stem cells of the present invention;

[0027] Figure 2 is a schematic diagram of the interior of the freezer of the present invention;

[0028] Figure 3 is a front view of the interior of the freezer of the present invention;

[0029] Figure 4 The present invention Figure 1 A magnified image of point A;

[0030] Figure 5 The present invention Figure 3 A magnified view of point B;

[0031] Figure 6 The present invention Figure 3 Enlarged view of point C;

[0032] Figure 7 The structure of the cleaning assembly of the present invention is shown in FIG. Figure 1 ;

[0033] Figure 8 The structure of the cleaning assembly of the present invention is shown in FIG. Figure 2 ;

[0034] Fig. 9 The present invention Figure 8 The enlarged view of point D;

[0035] Fig.10 It is a schematic diagram of the meshing transmission of the center rotating gear of the present invention;

[0036] Fig.11 It is a schematic diagram of the process of the long-term low-temperature freezing storage method of stem cells of the present invention.

[0037] Figure numerals: 1. freezer; 2. refrigerator; 3. dehumidification cleaning mechanism; 4. double-axis motor; 5. driving wheel; 6. first reciprocating screw; 7. driven wheel; 8. conveyor belt; 9. convex notch; 10. fixed block; 11. first bevel gear; 12. second reciprocating screw; 13. second bevel gear; 14. first slider; 15. shielding plate; 16. crossbeam; 17. cleaning assembly; 18. filter; 19. scraper; 20. blade; 21. compression spring; 22. push block; 23. first inclined plate; 24. second inclined plate; 25. sliding member; 26. guide wheel; 27. slope; 28. center gear; 29. ​​gear plate; 30. pressing mechanism; 31. second slider; 32. pressure roller; 33. support plate; 34. synchronization rod; 35. telescopic plug rod. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0039] Reference Manual Attached Figure 1 , Figure 2 and Figure 3 As shown, the stem cell long-term cryogenic freezer includes:

[0040] A freezer box 1, on which a refrigerator 2 adapted thereto is mounted, and a refrigeration port extending to the interior of the freezer box 1 is provided; a dehumidification and cleaning mechanism 3, which includes a double-axis motor 4 fixed to the inner wall of the freezer box 1, wherein one output end of the double-axis motor 4 is connected to a driving wheel 5, and the other end is connected to a first reciprocating screw 6, the driving wheel 5 and the driven wheel 7 are connected via a conveyor belt 8, and one end of the driving wheel 5 passes through the cover body and extends to a fixed block 10 provided with a convex notch 9.

[0041] A refrigerator 2 is provided to discharge cold air into the freezer 1 through compressor refrigeration technology, and the low-pressure gas is increased to high-pressure gas through the compressor, thereby realizing the refrigeration cycle process, which can effectively realize the cryopreservation of stem cells.

[0042] Among them, one end of the driven wheel 7 is fixedly connected to a first bevel gear 11, the outer wall of the first bevel gear 11 is meshed with a second bevel gear 13 fixed on a second reciprocating screw 12, the second reciprocating screw 12 is spirally driven with a first slider 14, the first slider 14 and the baffle plate 15 are fixedly connected by a cross beam 16, a ventilation hole is provided on the outer wall of the freezer 1 below the baffle plate 15, and the fixed block 10 and the ventilation hole are connected by a cleaning assembly 17.

[0043] Specifically, under normal circumstances, the ventilation holes on the freezer 1 are closed by the baffle plate 15. When the inside of the freezer 1 is to be dehumidified, the dual-axis motor 4 is started and drives the driving wheel 5 to rotate. Under the transmission action of the conveyor belt 8, the driven wheel 7 rotates synchronously, so that the first bevel gear 11 on the driven wheel 7 can drive the second reciprocating screw 12 on the second bevel gear 13 to rotate, and the meshing transmission of the bevel gears can achieve reversal adjustment of the power direction, so that the first slider 14 is lifted and lowered under the action of the spiral transmission and drives the baffle plate 15 on the crossbeam 16 to move synchronously. During the movement of the baffle plate 15, the structural components can close and open the ventilation holes.

[0044] refer to Figure 3 , Figure 5 , Figure 6 and Figure 7 The cleaning assembly 17 includes a filter 18 which is detachably mounted at the ventilation hole, a scraper 19 is mounted on one end of the filter 18 close to the outer wall of the freezer 1, and a blade 20 is connected to the other end. The scraper 19 and the blade 20 are distributed in a ring array, and the central axis of the scraper 19 passes through the filter 18 and extends to the blade 20. A push block 22 is connected to one end of the central axis through a compression spring 21. A first inclined plate 23 which can be inserted into the convex groove 9 is integrally formed on the top of the push block 22, and a second inclined plate 24 fixed on the shielding plate 15 is provided directly above the first inclined plate 23.

[0045] A dehumidification and cleaning mechanism 3 is set up. After the dual-axis motor 4 is started, it can drive the rotation of the driving wheel 5, and drive the rotation of the driven wheel 7 through the conveyor belt 8. Through the meshing transmission of the gears, the horizontal rotation force can be converted into the vertical rotation force. With the help of the spiral transmission, the baffle plate 15 can move upward and open the ventilation hole. At this time, the compression spring 21 can insert the push block 22 into the convex groove 9 of the fixed block 10 under the elastic recovery effect, so that the driving wheel 5 can drive the central axis to rotate synchronously. During the rotation of the central axis, the scraper 19 and the blade 20 can be driven to rotate. In this way, on the one hand, the dehumidification work inside the freezer 1 can be realized, and on the other hand, the impurities on the filter screen 18 can be removed, and the filter screen 18 itself can further maintain its cleanliness at the ventilation hole, thereby ensuring the normal operation of the device, which is conducive to effective dehumidification and cleaning work.

[0046] Both the first inclined plate 23 and the second inclined plate 24 are opened outwardly and tilted, and the inclined parts of the two are parallel. Both ends of the second inclined plate 24 are connected to guide wheels 26 through sliding members 25. Both sides of the top of the outer wall of the push block 22 are provided with slopes 27 connected to the guide wheels 26.

[0047] The shape setting of the first inclined plate 23 and the second inclined plate 24, on the one hand, can make the pushing block 22 move horizontally outward and move to the ventilation hole during the downward movement of the second inclined plate 24, so as to ensure that the shielding plate 15 normally closes the ventilation hole. On the other hand, a gap can be left at the connection between the second inclined plate 24 and the fixed block 10 to facilitate the downward insertion of the first inclined plate 23. In addition, it can also facilitate the first inclined plate 23 to be inserted into the convex groove 9 of the fixed block 10, so as to facilitate the subsequent driving wheel 5 to drive the rotation of the central axis.

[0048] Specifically, during the upward movement of the baffle plate 15, the second inclined plate 24 can be driven to move upward. At this time, the second inclined plate 24 is separated from the first inclined plate 23. Since the first inclined plate 23 is fixed on the pushing block 22, one end of the pushing block 22 can be inserted into the convex groove 9 matched with it under the elastic recovery action of the compression spring 21. Moreover, when the convex groove 9 is inserted between the first inclined plate 23 and the pushing block 22, a multi-point limit connection can be formed, so that the two are not easy to separate. The connection has strong stability, and the rotational force of the driving wheel 5 can be effectively and stably transmitted to the central axis. In addition, the internal and external designs of the blades 20 and the scraper 19 at both ends of the filter 18 can not only prevent external particulate impurities from entering the freezer 1, but also can effectively discharge the scraped impurities to the outside of the freezer 1 under the action of wind energy.

[0049] refer to Figure 2 , Figure 8 , Fig. 9and Fig.10 The sliding member 25 includes a central rotating tooth 28 placed in the inner groove of the second inclined plate 24. The upper and lower ends of the central rotating tooth 28 are meshed with gear plates 29 that move in the opposite direction. The gear plates 29 at both ends are both L-shaped, and the extension of one end of the gear plate 29 is connected to the guide wheel 26 through a bearing.

[0050] One end of the gear plate 29 is connected with a strip groove along the length direction of the inner wall of the second inclined plate 24, and the outer wall edge of the guide wheel 26 is provided with a rolling groove placed on the bearing. As the dual-axis motor 4 is started, the beam 16 drives the baffle plate 15 to open the ventilation hole, and at the same time the second inclined plate 24 moves upward, and the push block 22 is inserted into the convex groove 9 under the elastic recovery action of the compression spring 21, and drives the blade 20 and the scraper 19 to rotate synchronously.

[0051] A cleaning component 17 and a sliding member 25 are provided. When the shielding plate 15 moves downward, the ventilation hole is closed, and the second inclined plate 24 is inserted into the gap between the first inclined plate 23 and the fixed block 10, so that the first inclined plate 23 drives the pushing block 22 to move outward. The guide wheels 26 at both ends of the sliding member 25 can prevent the pushing block 22 from deviating from its position during the movement. Moreover, the movement is carried out by rolling friction, which can reduce the friction damage between the structural parts and improve the service life of the device. At the same time, the guide wheel 26 is connected with a center gear 28 through a gear plate 29, which can ensure the synchronization of the centering movement of the guide wheel 26 and further ensure the accuracy of the movement of the guide member.

[0052] During the downward movement of the second inclined plate 24, the sliding member 25 can be driven to move downward synchronously. The setting of the sliding member 25 can effectively prevent the pushing block 22 from deviating from its position during the translation process. Moreover, during the downward movement of the guide wheel 26, the setting of the slopes 27 at both ends of the pushing block 22 can not only increase the contact area with the guide wheel 26 and prevent a large resistance force from being generated during collision, so that the force can be dispersed, but also allow the guide wheel 26 to correct its position in time even when a certain position deviation occurs, so that the guide wheel 26 can accurately correct the position of the pushing block 22. Moreover, the gear plate 29 and the center gear 28 on the guide wheel 26 move synchronously, which has the effect of automatic position correction, thereby further ensuring that the accuracy of the movement of the transmission member can be automatically guaranteed.

[0053] The stem cell long-term low-temperature freezer also includes a pressing mechanism 30, which includes a second slider 31 that is spirally driven and placed on the first reciprocating screw 6. A pressing roller 32 is movably connected to the downwardly extending portion of the second slider 31. A support plate 33 placed inside the freezer 1 is provided below the pressing roller 32. A slide groove connected to the second slider 31 is provided on the support plate 33, and the pressing rollers 32 are connected by a synchronization rod 34. Telescopic rods 35 are installed at the diagonals on one side of the outer wall of the support plate 33. The telescopic rods 35 are connected to the side wall of the freezer 1 by plugging, and the support plates 33 are kept parallel.

[0054] Specifically, the pressing mechanism 30 is mainly to drive the rotation of the first reciprocating screw 6 after the dual-axis motor 4 is started, and then under the action of the spiral transmission, the pressing roller 32 presses the surface of the bag back and forth to maintain the flatness of the bag and prevent wrinkles, which is not conducive to the placement of the bag.

[0055] A pressing mechanism 30 is provided. After the dual-axis motor 4 is started, it can drive the rotation of the first reciprocating screw 6. Under the action of the spiral transmission, the pressing roller 32 on the second slider 31 can press the surface of the bag body, so that the bag body can ensure a certain flatness to prevent wrinkles, which is not conducive to the cryopreservation of stem cells. At the same time, the support plate 33 is connected to the freezer 1 by a telescopic plug-in method, which can achieve rapid installation, facilitate personnel operation, and improve work efficiency.

[0056] refer to Fig.11 , a method for long-term cryopreservation of stem cells, comprising the following steps:

[0057] S1.1. Place the bag containing stem cells on the support plate 33 of the freezer 1, start the dual-axis motor 4, and under the action of mechanical transmission, move the shielding plate 15 upward and open the vent hole. At this time, the compression spring 21 moves toward the inside of the freezer 1 under elastic recovery and is inserted into the convex notch 9 of the fixed block 10;

[0058] S1.2, the driving wheel 5 drives the central shaft to rotate, and drives the blades 20 and the scraper 19 on the filter 18 to rotate at the same time. The rotation of the blades 20 can accelerate the air flow, thereby accelerating the evaporation and dehumidification of water. In conjunction with the blades 20, the scraper 19 can effectively remove the particulate impurities on the filter 18;

[0059] S1.3. After the dual-axis motor 4 of step S1.1 is started, it can drive the rotation of the first reciprocating screw 6. Under the action of the spiral transmission, the second slider 31 drives the pressing roller 32 to press the bag body to ensure the flatness of the bag body. Finally, the refrigerator 2 is turned on to cool the inside of the freezer 1 through the compressor refrigeration technology.

[0060] The above-mentioned stem cell freezing operation method has a strong integrated structural design and high precision. It can effectively realize dehumidification and cleaning operations at the same time, and can automatically correct the position of the transmission parts to prevent external dust particles from entering the interior of the freezer 1. It does not require an additional power source, which is beneficial to environmental protection. Moreover, the entire operation process is simple and reasonable, which is convenient for personnel to operate and greatly improves work efficiency.

[0061] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0062] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A long-term low-temperature freezer for stem cells, characterized in that: include: A freezer box (1), wherein a refrigerator (2) adapted thereto is installed on the freezer box (1), and the refrigerator (2) is provided with a refrigeration port extending into the interior of the freezer box (1); A dehumidification cleaning mechanism (3), the dehumidification cleaning mechanism (3) comprising a double-shaft motor (4) fixed on the inner wall of the freezer (1), one output end of the double-shaft motor (4) being connected to a driving wheel (5), and the other output end being connected to a first reciprocating screw (6), the driving wheel (5) and the driven wheel (7) being connected by a transmission belt (8), one end of the driving wheel (5) passing through the cover and extending to a fixed block (10) having a convex notch (9); One end of the driven wheel (7) is fixedly connected to a first bevel gear (11); the outer wall of the first bevel gear (11) is meshed with a second bevel gear (13) fixed to a second reciprocating screw (12); the second reciprocating screw (12) is spirally driven with a first slider (14); the first slider (14) and the baffle plate (15) are fixedly connected via a crossbeam (16); a ventilation hole is provided on the outer wall of the freezer (1) below the baffle plate (15); and the fixed block (10) and the ventilation hole are connected via a cleaning assembly (17).

2. The stem cell long-term cryogenic freezer according to claim 1, characterized in that: The cleaning assembly (17) includes a filter (18) that is detachably mounted at the ventilation hole, a scraper (19) being mounted on one end of the filter (18) close to the outer wall of the freezer (1), and a blade (20) being connected to the other end, the scraper (19) and the blade (20) being arranged in a circular array, and a central axis on the scraper (19) passing through the filter (18) and extending to the blade (20), one end of the central axis being connected to a push block (22) via a compression spring (21), the top of the push block (22) being integrally formed with a first inclined plate (23) that can be inserted into the convex groove (9), and a second inclined plate (24) fixed to the shielding plate (15) being provided directly above the first inclined plate (23).

3. The stem cell long-term cryogenic freezer according to claim 2, characterized in that: The first inclined plate (23) and the second inclined plate (24) are both arranged with their openings tilted outwards, and their tilted portions are arranged parallel to each other; both ends of the second inclined plate (24) are connected to guide wheels (26) via sliding members (25); and both sides of the top end of the outer wall of the pushing block (22) are provided with slopes (27) connected to the guide wheels (26).

4. The stem cell long-term cryogenic freezer according to claim 3, characterized in that: The sliding member (25) comprises a central rotating tooth (28) disposed in an inner groove of the second inclined plate (24); the upper and lower ends of the central rotating tooth (28) are meshed with a gear plate (29) that moves in the opposite direction; the gear plates (29) at both ends are both L-shaped, and a guide wheel (26) is connected to an extension of one end of the gear plate (29) via a bearing.

5. The stem cell long-term cryogenic freezer according to claim 4, characterized in that: One end of the gear plate (29) is connected with a strip groove along the length direction of the inner wall of the second inclined plate (24), and the outer wall edge of the guide wheel (26) is provided with a rolling groove placed on the bearing. When the dual-axis motor (4) is started, the crossbeam (16) drives the shielding plate (15) to open the ventilation hole, and at the same time the second inclined plate (24) moves upward, and the push block (22) is inserted into the convex groove (9) under the elastic recovery action of the compression spring (21), and drives the blade (20) and the scraper (19) to rotate synchronously.

6. The stem cell long-term cryogenic freezer according to claim 1, characterized in that: The invention also comprises a pressing mechanism (30), wherein the pressing mechanism (30) comprises a second slider (31) which is placed on the first reciprocating screw (6) and is driven by a screw, and a pressing roller (32) is movably connected to the downwardly extending portion of the second slider (31), and a support plate (33) which is placed inside the freezer (1) is provided below the pressing roller (32), and a slide groove which is connected to the second slider (31) is provided on the support plate (33), and the pressing rollers (32) are connected to each other via a synchronization rod (34).

7. The stem cell long-term cryogenic freezer according to claim 6, characterized in that: A telescopic plug rod (35) is installed at a diagonal position on one side of the outer wall of the support plate (33), and the telescopic plug rod (35) is connected to the side wall of the freezer (1) by plugging, and the support plates (33) are kept parallel to each other.

8. A method for long-term cryopreservation of stem cells, according to the long-term cryopreservation machine for stem cells according to any one of claims 1 to 7, characterized in that: The steps include: S1.

1. Place the bag containing stem cells on the support plate (33) of the freezer (1), start the dual-axis motor (4), and under the action of mechanical transmission, move the shielding plate (15) upward and open the ventilation hole. At this time, the compression spring (21) moves toward the inside of the freezer (1) under elastic recovery and is inserted into the convex notch (9) of the fixed block (10) to limit the position; S1.2, the driving wheel (5) drives the central shaft to rotate, and drives the blades (20) and the scraper (19) on the filter (18) to rotate simultaneously. The rotation of the blades (20) can accelerate the air flow, thereby accelerating the evaporation and dehumidification of water. In conjunction with the blades (20), the scraper (19) can effectively remove the particulate impurities on the filter (18); S1.3, after the dual-axis motor (4) of step S1.1 is started, it can drive the first reciprocating screw (6) to rotate. Under the action of the spiral transmission, the second slider (31) drives the pressing roller (32) to press the bag body to ensure the flatness of the bag body. Finally, the refrigerator (2) is turned on to cool the inside of the freezer (1) through the compressor refrigeration technology.

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