Sample cooling and storage method

Abstract

The present invention relates to a sample cooling and storage method. A programmed cooling method is divided into multiple stages of cooling methods corresponding to a standard environmental cooling curve. Each cooling stage, by means of determining whether or not an actual environment temperature T1 is equal to a target environment temperature w, determines whether or not the sample requires heating or cooling, causing the actual environment temperature T1 to be consistent with the target environment temperature w until the actual environment temperature T1 is consistent with the target temperature T2 of the cooling stage. After a sample has been subjected to each stage of cooling treatment in sequence, the required temperature for cryogenic storage is finally achieved, and the sample is directly stored in a liquid nitrogen storage box. The sample cooling and storage method of the present invention can implement programmed cooling and sample storage, and facilitates handling of single-layer samples.

Description

A method for cooling and storing a sample Technical Field

[0001] The present invention relates to a biological sample storage method, and in particular to a sample cooling and storage method. Background Art

[0002] In order to improve the survival rate of frozen cells, the temperature of the cells needs to be gradually reduced to a predetermined temperature through programmed cooling before storage. Curve A in Figure 1 is the standard environmental cooling curve set by the programmed cooling requirements, and curve B is the actual cooling curve of the sample. As can be seen from the figure, the programmed cooling process is divided into several stages. For this purpose, it is necessary to set up multiple independent cooling devices to cool the cells in stages. In order to achieve the above purpose, the Chinese patent with publication number CN 217509762U discloses a sample programmed cooling device, which connects multiple independent low-temperature storage boxes in series through a conveying system, so that cells can be transported between multiple low-temperature storage boxes, and cooled to the target temperature in each low-temperature storage box according to the specific cooling rate of a certain programmed cooling stage, thereby finally achieving the purpose of programmed cooling.

[0003] As can be seen from the above description, this sample programmed cooling device requires multiple independent dedicated cooling devices to cool the samples. After cooling, the samples must be transferred to independent low-temperature storage facilities for storage. This is effective when processing large batches of biological samples. However, when processing single-layer samples, the separation of programmed cooling and sample storage requires multiple dedicated devices during the cooling process, making operation more cumbersome and inconvenient for single-layer sample processing, resulting in poor performance.

[0004] To this end, a programmed cooling and storage method needs to be designed to simultaneously achieve programmed cooling and sample storage, thereby improving the convenience of single-layer sample processing.

[0005] Summary of the Invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a sample cooling and storage method that can simultaneously achieve programmed cooling and sample storage, and is convenient for processing single-layer samples.

[0007] The sample cooling and storage method of the present invention includes the steps of placing the sample in a liquid nitrogen storage box. The sample cooling and storage method uses a lifting device to lift the sample in the liquid nitrogen storage box, performs programmed cooling on the sample, and directly stores the sample in the liquid nitrogen storage box after the programmed cooling. The programmed cooling method includes the following steps:

[0008] The programmed cooling is divided into several stages corresponding to the standard ambient cooling curve and executed in sequence. Each stage of cooling includes the following steps:

[0009] S1: Set the target ambient temperature w in real time according to the standard ambient cooling curve;

[0010] S2: Get the actual ambient temperature T1;

[0011] S3: Compare the target ambient temperature w and the actual ambient temperature T1 and control the rise and fall of the sample;

[0012] If the target ambient temperature w is higher than the actual ambient temperature T1, the sample is lowered to a predetermined height;

[0013] If the target ambient temperature w is lower than the actual ambient temperature T1, the sample is raised to a predetermined height;

[0014] If the target ambient temperature w is equal to the actual ambient temperature T1, then determine whether the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage.

[0015] If the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage, then the cooling in this stage is terminated.

[0016] If the actual ambient temperature T1 is not equal to the target temperature T2 for cooling in this stage, steps S1 to S3 are executed in a loop until the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage.

[0017] Furthermore, in the cooling and storage method of the sample of the present invention, during the cooling process at each stage, the programmable controller controls the output of the servo motor through the PID algorithm, and the operation adjustment equation of the PID algorithm is as follows:

[0018] Among them, Δy is the output value of the PID algorithm; K P is the proportional gain, s is the Laplace operator, b is the proportional action weight, w is the set target ambient temperature, x is the actual ambient temperature of the sample, K i is the integral action time, a is the differential delay coefficient, K d is the differential action time, and c is the differential action weight.

[0019] Furthermore, in the sample cooling and storage method of the present invention, the lifting device is a linear displacement driver driven by a servo motor.

[0020] Furthermore, in the method for cooling and storing samples of the present invention, the liquid nitrogen storage box is arranged in a sample storage device, the sample storage device includes a tank body, a tank cover is provided on the top of the tank body, a rotating frame is provided in the inner cavity of the tank body, the rotating frame includes a frame body and a rotating main shaft connected to the frame body, the bottom end of the rotating main shaft is provided on the bearing seat in the center of the bottom of the tank body, the top end of the rotating main shaft passes through the tank cover and is connected to the output shaft of the rotation drive device, the body of the rotation drive device is fixed on the tank cover, the liquid nitrogen storage box is connected to the frame body, the surface of the tank cover is provided with a transfer port corresponding to the liquid nitrogen storage box, and a tank plug is provided at the transfer port.

[0021] Furthermore, in the sample cooling and storage method of the present invention, the liquid nitrogen storage box is a rectangular box body with an open top, and a plurality of liquid nitrogen storage boxes are arranged on the frame body around the rotating main axis.

[0022] Furthermore, in the sample cooling and storage method of the present invention, a basket-type sample storage rack is provided in the liquid nitrogen storage tank, and the basket-type sample storage rack is adapted to the liquid nitrogen storage box. The basket-type sample storage rack includes a storage rack body, and a connector connected to the output end of the lifting device is provided at the top of the storage rack body. The storage rack body is provided with several layers of storage tanks with front end openings from top to bottom, and a single layer of samples is placed in the storage tanks.

[0023] Furthermore, in the sample cooling and storage method of the present invention, the origin in the liquid nitrogen storage box is 250 mm away from the liquid surface.

[0024] Furthermore, in the sample cooling and storage method of the present invention, the rotation drive device includes a drive motor and a reducer, the output shaft of the drive motor is connected to the input shaft of the reducer, the output shaft of the reducer is connected to the rotating central axis, the reducer is a right-angle reducer, and its body is fixed on the fixing bracket on the surface of the tank cover, and the fixing bracket is fixed on the surface of the tank cover.

[0025] Furthermore, in the sample cooling and storage method of the present invention, bearings are provided between the top end of the rotating central shaft and the tank cover, and between the bottom end of the rotating central shaft and the bearing seat at the bottom of the tank body.

[0026] Furthermore, in the sample cooling and storage method of the present invention, the top end of the reducer output shaft is also connected to a turntable.

[0027] Furthermore, in the sample cooling and storage method of the present invention, a shielding piece is provided on the turntable, a vertical plate is provided on one side of the reducer, a U-shaped photoelectric switch is provided on the top of the vertical plate, and the bottom end of the vertical plate is fixed on the fixed frame, and the shielding piece can pass through the U-groove of the U-shaped photoelectric switch.

[0028] Furthermore, in the sample cooling and storage method of the present invention, the frame includes a top frame plate, a bottom frame plate and several connecting vertical plates connecting the top frame plate and the bottom frame plate, and the middle part of the top frame plate and the middle part of the bottom frame plate are respectively fixedly connected to the rotating central axis.

[0029] Furthermore, in the sample cooling and storage method of the present invention, the top end of the liquid nitrogen storage box is connected to the edge of the top frame plate by bolts, and the edge of the top frame plate is provided with a positioning slot adapted to the liquid nitrogen storage box.

[0030] The present sample cooling and storage method divides programmed cooling into several stages corresponding to a standard ambient cooling curve. Each stage determines whether the actual ambient temperature T1 is equal to the target ambient temperature w, determining whether the sample needs to be raised or lowered to bring the actual ambient temperature T1 and the target ambient temperature w into alignment. This process continues until the actual ambient temperature T1 matches the target temperature T2 for that stage. After sequentially cooling through each stage, the sample ultimately reaches the desired cryogenic storage temperature and is directly stored in a liquid nitrogen storage box.

[0031] Compared with the existing programmed cooling and sample storage methods, this sample cooling and storage method achieves programmed cooling of the samples by raising and lowering the samples in a liquid nitrogen storage box. After reaching the deep-cold storage temperature, the samples are directly stored in the liquid nitrogen storage box. The cooling and preservation process only involves a single programmed cooling and preservation device, which is very convenient for programmed cooling and preservation operations of single-layer samples.

[0032] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement them in accordance with the contents of the specification, the embodiments of the present invention are described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 shows the standard environment cooling curve and the actual cooling curve of the sample;

[0034] FIG2 is a graph showing the ambient temperature from the origin to 600 mm in the liquid nitrogen storage box;

[0035] FIG3 is a flow chart of the program cooling of the sample;

[0036] FIG4 is a flow chart of the stage cooling of the sample;

[0037] FIG5 is a front view of the sample storage device;

[0038] FIG6 is a cross-sectional view of a sample storage device;

[0039] FIG7 is a perspective view of a sample storage device;

[0040] FIG8 is a connection diagram of the rotating frame and the rotation drive device;

[0041] FIG9 is a perspective view of the rotary drive device;

[0042] FIG10 is a perspective view of a liquid nitrogen storage box;

[0043] FIG11 is a perspective view of a basket-type storage rack;

[0044] FIG12 is another cross-sectional view of the sample storage device;

[0045] FIG13 is a diagram showing the connection between the sample storage device and the housing.

[0046] Among them, there are liquid nitrogen storage box 1, tank body 2, tank cover 3, frame 4, rotating spindle 5, bearing seat 6, transmission port 7, tank plug 8, storage frame 9, connector 10, storage slot 11, drive motor 12, reducer 13, fixing frame 14, turntable 15, shielding piece 16, vertical plate 17, U-shaped photoelectric switch 18, top frame plate 19, bottom frame plate 20, connecting vertical plate 21, positioning slot 22, and casing 23. DETAILED DESCRIPTION

[0047] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0048] 1 to 13 , the sample cooling and storage method of this embodiment includes the steps of placing the sample in a liquid nitrogen storage box. The sample cooling and storage method uses a lifting device to lift the sample in the liquid nitrogen storage box, performs programmed cooling on the sample, and directly stores the sample in the liquid nitrogen storage box after the programmed cooling. The programmed cooling method includes the following steps:

[0049] The programmed cooling is divided into several stages corresponding to the standard ambient cooling curve and executed in sequence. Each stage of cooling includes the following steps:

[0050] S1: Set the target ambient temperature w in real time according to the standard ambient cooling curve;

[0051] S2: Get the actual ambient temperature T1;

[0052] S3: Compare the target ambient temperature w and the actual ambient temperature T1 and control the rise and fall of the sample;

[0053] If the target ambient temperature w is higher than the actual ambient temperature T1, the sample is lowered to a predetermined height;

[0054] If the target ambient temperature w is lower than the actual ambient temperature T1, the sample is raised to a predetermined height;

[0055] If the target ambient temperature w is equal to the actual ambient temperature T1, then determine whether the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage.

[0056] If the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage, then the cooling in this stage is terminated.

[0057] If the actual ambient temperature T1 is not equal to the target temperature T2 for cooling in this stage, steps S1 to S3 are executed in a loop until the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage.

[0058] The present sample cooling and storage method divides programmed cooling into several stages corresponding to a standard ambient cooling curve. Each stage determines whether the actual ambient temperature T1 is equal to the target ambient temperature w, determining whether the sample needs to be raised or lowered to bring the actual ambient temperature T1 and the target ambient temperature w into alignment. This process continues until the actual ambient temperature T1 matches the target temperature T2 for that stage. After sequentially cooling through each stage, the sample ultimately reaches the desired cryogenic storage temperature and is directly stored in a liquid nitrogen storage box.

[0059] Compared with the existing programmed cooling and sample storage methods, this sample cooling and storage method achieves programmed cooling of the samples by raising and lowering the samples in a liquid nitrogen storage box. After reaching the deep-cold storage temperature, the samples are directly stored in the liquid nitrogen storage box. The cooling and preservation process only involves a single programmed cooling and preservation device, which is very convenient for programmed cooling and preservation operations of single-layer samples.

[0060] The liquid nitrogen storage box is used to store liquid nitrogen, and can be an independent liquid nitrogen storage device, or be arranged in a sample storage device.

[0061] In this embodiment, a liquid nitrogen storage box 1 is a rectangular box with an open top, which is installed in a sample storage device. The sample storage device includes a tank body 2, a tank cover 3 is installed at the top of the tank body, and a rotating frame is installed in the inner cavity of the tank body. The rotating frame includes a frame body 4 and a rotating spindle 5 connected to the frame body. The bottom end of the rotating spindle is installed on a bearing seat 6 at the center of the bottom of the tank body. The top end of the rotating spindle passes through the tank cover and is connected to the output shaft of the rotation drive device. The body of the rotation drive device is fixed to the tank cover. The liquid nitrogen storage box is connected to the frame body. The surface of the tank cover is provided with a transfer port 7 corresponding to the liquid nitrogen storage box, and the transfer port is provided with a tank plug 8.

[0062] During specific implementation, multiple liquid nitrogen storage boxes are arranged on the frame around the rotating main shaft. The rotating main shaft drives the rotating frame to rotate under the drive of the rotating drive device, so as to rotate the corresponding liquid nitrogen storage box to the bottom of the transmission port for subsequent lifting device to operate on the sample.

[0063] To improve thermal insulation, the tank is double-layered, storing liquid nitrogen. Liquid nitrogen in the tank flows through a channel into the liquid nitrogen storage box. The liquid nitrogen storage box has a smaller cross-section than the tank itself, resulting in virtually uniform temperature differences within the box at the same level. However, due to the tank's larger size, temperatures vary significantly at different locations within the same level, making it unsuitable for programmed cooling.

[0064] In order to facilitate the lifting and lowering operations of single-layer samples, a basket-type sample storage rack is provided in the liquid nitrogen storage tank. The basket-type sample storage rack is adapted to the liquid nitrogen storage box and includes a storage rack body 9. A connector 10 connected to the output end of the lifting device is provided on the top of the storage rack body. The storage rack body is provided with several layers of storage slots 11 with front end openings from top to bottom, and single-layer samples are placed in the storage slots.

[0065] In this embodiment, the origin of the liquid nitrogen storage box is 250 mm from the liquid surface. Figure 2 shows the ambient temperature curve from the origin to 600 mm. As can be seen from the figure, the ambient temperature changes little from the origin to the 250 mm position, remaining essentially below -180°C. As the position increases from 250 mm to 600 mm, the ambient temperature rises from -180°C to 5°C. The 600 mm position is located at the exit of the transfer port. When the basket-type storage rack reaches its lowest point, the 22nd storage slot is at the origin.

[0066] Among them, the rotation drive device is used to drive the rotating central axis to rotate, thereby driving the frame and the liquid nitrogen storage box thereon to rotate, so that the corresponding liquid nitrogen storage box rotates to the bottom of the transfer port, so that the lifting device can operate the basket-type storage rack and the samples thereon.

[0067] In this embodiment, the rotation drive device includes a drive motor 12 and a reducer 13. The output shaft of the drive motor is connected to the input shaft of the reducer, and the output shaft of the reducer is connected to the rotating central axis. The reducer is a right-angle reducer, and its body is fixed on a fixing bracket 14 on the surface of the tank cover, and the fixing bracket is fixed on the surface of the tank cover.

[0068] During operation, the output shaft of the drive motor drives the reduction motor to rotate, thereby driving the rotating central shaft at the output end of the reducer to rotate.

[0069] Bearings are provided between the top end of the rotating central shaft and the tank cover, and between the bottom end of the rotating central shaft and the bearing seat at the bottom of the tank body to reduce friction.

[0070] The top end of the speed reducer output shaft is also connected to a turntable 15, and a scale is provided on the surface of the turntable to facilitate the operator to observe the position of the rotating frame.

[0071] In order to limit the rotating frame, a shielding piece 16 is provided on the turntable, a vertical plate 17 is provided on one side of the reducer, a U-shaped photoelectric switch 18 is provided on the top of the vertical plate, and the bottom end of the vertical plate is fixed on the fixed frame. The shielding piece can pass through the U-groove of the U-shaped photoelectric switch.

[0072] The U-shaped photoelectric switch and shielding plate limit the rotating frame. Specifically, the turntable rotates under the drive of the reducer output shaft, which in turn drives the shielding plate on it. When the shielding plate reaches the U-slot of the U-shaped photoelectric switch, the light path of the U-shaped photoelectric switch is blocked, causing it to generate a corresponding pulse signal. The external control circuit uses this pulse signal to stop the drive motor and reducer and issue a warning message to alert the operator.

[0073] Preferably, the frame includes a top frame plate 19, a bottom frame plate 20, and several connecting vertical plates 21 connecting the top and bottom frames. The middle portions of the top and bottom frames are respectively fixedly connected to the central axis of rotation. The top and bottom frames are each provided with several hollow holes to reduce their weight. The top end of the liquid nitrogen storage box is bolted to the edge of the top frame plate. The edge of the top frame plate is provided with a positioning slot 22 adapted to the liquid nitrogen storage box to achieve positioning of the liquid nitrogen storage box.

[0074] The lifting device is used to drive the sample to move up and down in the liquid nitrogen storage box, and realizes programmed cooling and preservation of the sample through the corresponding control program.

[0075] In this embodiment, the lifting device is a linear actuator driven by a servo motor. The linear actuator is mounted on the output of the three-dimensional motion mechanism, which is housed within a housing 23 above the tank. A manipulator is connected to the output of the linear actuator, which corresponds to the connector at the top of the basket lifter.

[0076] During operation, the three-dimensional moving mechanism moves the lifting device to the top of the transmission port, and then the linear displacement driver drives the manipulator and the basket-type storage rack connected to it to descend under the drive of the servo motor. After that, the external controller cools down and stores the sample according to the above-mentioned program cooling method. After the storage is completed, all components are reset and ready for the next work.

[0077] In this embodiment, according to the standard ambient cooling curve, programmed cooling is divided into five stages, corresponding to the five stage cooling line segments a, b, c, d, and e of curve 1 in FIG1 , which are close to straight lines. The temperature control equations for each stage cooling are as follows:

[0078] w=Kx+b;

[0079] Among them, w is the set target ambient temperature, x is the cooling time, k is the cooling rate, and b is the starting point temperature of this curve.

[0080] Step S1 sets the target ambient temperature w in real time according to the standard ambient cooling curve. The standard ambient cooling curve is the stage cooling curve corresponding to the current stage, corresponding to the aforementioned temperature control equation. Real time here refers to a short interval, such as 1 second, and is determined based on system accuracy and other requirements.

[0081] The actual ambient temperature T1 of step S2 can be obtained by setting a temperature sensor at the location of the single-layer sample of the basket-type storage rack to obtain the actual ambient temperature T1 of the environment where the sample is located.

[0082] In step S3, the predetermined height for lifting the sample can be a fixed height set manually, such as 1 cm, or can be automatically set by the system according to the temperature gradient so that the sample can reach the actual ambient temperature as quickly as possible.

[0083] In step S3, the target temperature T2 of the stage cooling is the end temperature of the stage cooling line segment corresponding to each stage cooling on the standard ambient cooling curve.

[0084] During the cooling process at each stage, the programmable controller controls the output of the servo motor through the PID algorithm. The calculation and adjustment equation of the PID algorithm is as follows;

[0085] Among them, Δy is the output value of the PID algorithm; K P is the proportional gain, s is the Laplace operator, b is the proportional action weight, w is the set target ambient temperature, x is the actual ambient temperature of the sample, K i is the integral action time, a is the differential delay coefficient, K d is the differential action time, c is the differential action weight;

[0086] Among them, K P ,b,K i ,a,K d The specific reference of c is set manually or automatically by the system according to the requirements of accuracy and stability.

[0087] The output of the servo motor is controlled by the PID algorithm, and the lifting device is used to control the lifting of the basket storage rack and the sample, which can achieve precise lifting of the sample and complete the programmed cooling.

[0088] In the PID algorithm, P refers to the proportional controller, I refers to the integral controller, and D refers to the differential controller. In the proportional controller, the regulation rule is that the controller's output signal u is proportional to the deviation e (deviation e = set value w - process value x), and its equation is as follows: u = K P e=K P (wx)

[0089] In the differential controller, the regulation rule is that the deviation e (deviation e = set value w - process value x) is integrated by the integral controller to obtain the controller output signal u, and its equation is as follows:

[0090] In differential control, the regulation rule is that the deviation e is differentially controlled by the differential controller to obtain the output signal u of the controller, that is, the rate of change of the output u of the control and the deviation The equation is as follows:

[0091] Proportional, integral and differential controllers each have their own advantages and disadvantages. In the temperature control system of the basket lifting program cooling, using only one controller cannot achieve the expected effect. It is necessary to combine the three, that is, the output of the control signal u=P+I+D, and reasonably optimize K P , K i , K d And other related parameters. The final PID regulator equation is as follows;

[0092] Right now

[0093] The PID operation adjustment equation obtained by derivation and limit operation of the above formula is as follows:

[0094] The above is only a preferred embodiment of the present invention, which is used to assist those skilled in the art to implement the corresponding technical solutions, and is not used to limit the scope of protection of the present invention, which is defined by the appended claims. It should be pointed out that for those skilled in the art, a number of equivalent improvements and variations can be made based on the technical solution of the present invention, and these improvements and variations should also be regarded as the scope of protection of the present invention. At the same time, it should be understood that although this specification is described in accordance with the above-mentioned embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions of each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for cooling and storing a sample, comprising the step of placing the sample in a liquid nitrogen storage box, characterized in that: The method for cooling and storing a sample comprises lifting and lowering the sample in a liquid nitrogen storage box by a lifting device, performing programmed cooling on the sample, and directly storing the sample in a liquid nitrogen storage box after the programmed cooling. The programmed cooling method comprises the following steps: The programmed cooling is divided into several stages of cooling corresponding to the standard ambient cooling curve and executed in sequence, and each stage of cooling includes the following steps; S1: Set the target ambient temperature w in real time according to the standard ambient cooling curve; S2: Get the actual ambient temperature T1; S3: Compare the target ambient temperature w and the actual ambient temperature T1 and control the rise and fall of the sample; If the target ambient temperature w is higher than the actual ambient temperature T1, the sample is lowered to a predetermined height; If the target ambient temperature w is lower than the actual ambient temperature T1, the sample is raised to a predetermined height; If the target ambient temperature w is equal to the actual ambient temperature T1, then determine whether the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage. If the actual ambient temperature T1 is equal to the target temperature T2 of this stage of cooling, then the cooling of this stage is terminated; If the actual ambient temperature T1 is not equal to the target temperature T2 for cooling in this stage, steps S1 to S3 are executed in a loop until the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage.

2. The method for cooling and storing a sample according to claim 1, characterized in that: During the cooling process at each stage, the programmable controller controls the output of the servo motor through the PID algorithm. The calculation and adjustment equation of the PID algorithm is as follows: Among them, Δy is the output value of the PID algorithm; K P is the proportional gain, s is the Laplace operator, b is the proportional action weight, w is the set target ambient temperature, x is the actual ambient temperature of the sample, K i is the integral action time, a is the differential delay coefficient, K d is the differential action time, and c is the differential action weight.

3. The method for cooling and storing a sample according to claim 1, characterized in that: The lifting device is a linear displacement driver driven by a servo motor.

4. The method for cooling and storing a sample according to claim 3, characterized in that: The liquid nitrogen storage box is arranged in a sample storage device, which includes a tank body, a tank cover is arranged on the top of the tank body, a rotating frame is arranged in the inner cavity of the tank body, the rotating frame includes a frame body and a rotating main shaft connected to the frame body, the bottom end of the rotating main shaft is arranged on a bearing seat at the center of the bottom of the tank body, the top end of the rotating main shaft passes through the tank cover and is connected to the output shaft of a rotating drive device, the body of the rotating drive device is fixedly arranged on the tank cover, the liquid nitrogen storage box is connected to the frame body, the surface of the tank cover is provided with a transmission port corresponding to the liquid nitrogen storage box, and a tank plug is provided at the transmission port.

5. The method for cooling and storing a sample according to claim 4, characterized in that: The liquid nitrogen storage box is a rectangular box body with an open top, and a plurality of liquid nitrogen storage boxes are arranged on the frame body around a rotating main axis.

6. The method for cooling and storing a sample according to claim 4, characterized in that: A basket-type sample storage rack is provided in the liquid nitrogen storage tank. The basket-type sample storage rack is adapted to the liquid nitrogen storage box. The basket-type sample storage rack includes a storage rack body. A connector connected to the output end of the lifting device is provided at the top of the storage rack body. The storage rack body is provided with several layers of storage tanks with front end openings from top to bottom, and a single layer of samples is placed in the storage tanks.

7. The method for cooling and storing a sample according to claim 4, characterized in that: The origin in the liquid nitrogen storage box is 250 mm away from the liquid surface.

8. The method for cooling and storing a sample according to claim 4, characterized in that: The rotation drive device includes a drive motor and a reducer, the output shaft of the drive motor is connected to the input shaft of the reducer, the output shaft of the reducer is connected to the rotating central axis, the reducer is a right-angle reducer, and its body is fixed on a fixing frame on the surface of the tank cover, and the fixing frame is fixed on the surface of the tank cover.

9. The method for cooling and storing a sample according to claim 8, characterized in that: Bearings are arranged between the top end of the rotating central axis and the tank cover, and between the bottom end of the rotating central axis and the bearing seat at the bottom of the tank body.

10. The method for cooling and storing a sample according to claim 8, characterized in that: The top end of the reducer output shaft is also connected with a turntable.

11. The method for cooling and storing a sample according to claim 10, characterized in that: The turntable is provided with a shielding piece, a vertical plate is provided on one side of the reducer, a U-shaped photoelectric switch is provided on the top of the vertical plate, the bottom end of the vertical plate is fixed on the fixing frame, and the shielding piece can pass through the U groove of the U-shaped photoelectric switch.

12. The method for cooling and storing a sample according to claim 4, characterized in that: The frame body comprises a top frame plate, a bottom frame plate and a plurality of connecting vertical plates connecting the top frame plate and the bottom frame plate. The middle part of the top frame plate and the middle part of the bottom frame plate are respectively fixedly connected to the rotating central axis.

13. The method for cooling and storing a sample according to claim 12, characterized in that: The top end of the liquid nitrogen storage box is connected to the edge of the top frame plate by bolts, and the edge of the top frame plate is provided with a positioning slot adapted to the liquid nitrogen storage box.

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