A method for cooling and storing samples

Abstract

This invention relates to a method for cooling and storing samples. The programmed cooling method is divided into several stages corresponding to a standard environmental cooling curve. Each stage determines whether sample temperature needs to be raised or lowered by judging whether the actual environmental temperature T1 equals the target environmental temperature w, until the actual environmental temperature T1 matches the target environmental temperature w, until the actual environmental temperature T1 matches the target temperature T2 of that stage. After sequentially undergoing each stage of cooling, the sample finally reaches the temperature required for cryogenic storage and is directly stored in a liquid nitrogen storage container. This invention's sample cooling and storage method can simultaneously achieve programmed cooling and sample storage, facilitating the processing of single-layer samples.

Description

Technical Field

[0001] This invention relates to a method for storing biological samples, and more particularly to a method for cooling and storing samples. Background Technology

[0002] To improve the survival rate of cryopreserved cells, the cells need to be gradually cooled to a predetermined temperature before storage. Figure 1 Curve A represents the standard environmental cooling curve set for the programmed cooling requirement, while curve B represents the actual cooling curve of the sample. As can be seen from the figures, the programmed cooling process is divided into several stages, requiring multiple independent cooling devices to cool the cells in stages. To achieve this, Chinese Patent Publication No. CN 217509762U discloses a sample programmed cooling device that connects multiple independent cryogenic storage boxes in series via a transport system. This allows cells to be transported between the boxes and cooled to the target temperature within each box according to a specific cooling rate for a particular stage of the programmed cooling process, ultimately 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 also need to be transferred to independent low-temperature storage devices for storage. This method is effective when processing large batches of biological samples. However, when processing single-layer samples, because the programmed cooling and sample storage are separated, and multiple dedicated devices are involved in the cooling process, the operation is cumbersome, inconvenient for processing single-layer samples, and the overall effect is poor.

[0004] Therefore, a programmed cooling and storage method needs to be designed to simultaneously achieve programmed cooling and sample storage, thereby improving the convenience of processing single-layer samples. Summary of the Invention

[0005] To address the aforementioned technical problems, the purpose of this invention is to provide a method for cooling and storing samples that can simultaneously achieve programmed cooling and sample storage, facilitating the processing of single-layer samples.

[0006] The sample cooling and storage method of the present invention includes the step of placing the sample into 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 to perform programmed cooling of the sample, and after programmed cooling, the sample is directly stored in the liquid nitrogen storage box. The programmed cooling method includes the following steps.

[0007] The cooling process is divided into several stages that correspond to the standard ambient cooling curve and are executed sequentially. Each stage of cooling includes the following steps.

[0008] S1: Set the target ambient temperature W in real time according to the standard ambient cooling curve;

[0009] S2: Obtain the actual ambient temperature T1;

[0010] S3: Compare the target ambient temperature w with the actual ambient temperature T1 and control the rise and fall of the sample.

[0011] If the target ambient temperature w is higher than the actual ambient temperature T1, then the sample will be lowered to the predetermined height.

[0012] If the target ambient temperature w is lower than the actual ambient temperature T1, then increase the predetermined height of the sample.

[0013] 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 this cooling stage.

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

[0015] If the actual ambient temperature T1 is not equal to the target temperature T2 for cooling in this stage, then repeat steps S1 to S3 until the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage.

[0016] Furthermore, in the sample cooling and storage method of the present invention, during each stage of cooling, the programmable controller controls the output of the servo motor through a PID algorithm. The calculation and adjustment equation of the PID algorithm is as follows.

[0017]

[0018] Where Δy is the output value of the PID algorithm; K P Here, s represents the proportional gain, b represents the proportional gain weight, w represents the target ambient temperature, x represents the actual ambient temperature of the sample, and K represents the proportional gain weight. i Let K be the integral action time, a be the differential delay coefficient, and K be the integral action time. 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 sample cooling and storage method of the present invention, the liquid nitrogen storage box is disposed in a sample storage device, the sample storage device includes a tank, a tank cover is disposed at the top of the tank, a rotating frame is disposed in the inner cavity of the tank, 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 disposed 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 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, and 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.

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

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

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

[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, and the output shaft of the reducer is connected to the rotation central shaft. The reducer is a right-angle reducer, and its body is fixed on a fixing frame on the surface of the can lid. The fixing frame is fixed on the surface of the can lid.

[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 can lid, and between the bottom end of the rotating central shaft and the bearing seat at the bottom of the can body.

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

[0027] Furthermore, in the sample cooling and storage method of the present invention, the turntable is provided with a shielding plate, 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 fixed frame, and the shielding plate 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 a plurality of connecting vertical plates connecting the top frame plate and the bottom frame plate, wherein the middle part of the top frame plate and the middle part of the bottom frame plate are respectively fixedly connected to the rotation central axis.

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

[0030] The present invention discloses a sample cooling and storage method that divides the programmed cooling process into several stages corresponding to a standard environmental cooling curve. Each stage determines whether the sample needs to be cooled or cooled further by judging whether the actual environmental temperature T1 equals the target environmental temperature w, until the actual environmental temperature T1 matches the target environmental temperature w, until the actual environmental temperature T1 matches the target temperature T2 of that stage. After sequentially undergoing each stage of cooling, the sample finally reaches the temperature required for cryogenic storage and is directly stored in a liquid nitrogen storage container.

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

[0032] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the following describes the embodiments of the present invention in detail. Attached Figure Description

[0033] Figure 1 The graph shows the standard environmental cooling curve and the actual cooling curve of the sample.

[0034] Figure 2 It is a temperature curve of the liquid nitrogen storage box from the origin to 600 mm.

[0035] Figure 3 This is the overall process flow chart for the sample's cooling procedure;

[0036] Figure 4 This is a flowchart of the phased cooling process for the sample;

[0037] Figure 5 This is the main view of the sample storage device;

[0038] Figure 6 This is a cross-sectional view of the sample storage device;

[0039] Figure 7It is a 3D view of the sample storage device;

[0040] Figure 8 This is a connection diagram of the rotating frame and the rotation drive device;

[0041] Figure 9 It is a three-dimensional view of the rotation drive device;

[0042] Figure 10 This is a 3D view of the liquid nitrogen storage box;

[0043] Figure 11 It is a 3D view of a basket-style storage rack;

[0044] Figure 12 This is another cross-sectional view of the sample storage device;

[0045] Figure 13 This is a diagram showing the connection between the sample storage device and the casing.

[0046] The components include: 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 rack 9, connector 10, storage tank 11, drive motor 12, reducer 13, fixed frame 14, turntable 15, shielding plate 16, upright plate 17, U-shaped photoelectric switch 18, top frame plate 19, bottom frame plate 20, connecting vertical plate 21, positioning slot 22, and housing 23. Detailed Implementation

[0047] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0048] See Figures 1 to 13 The sample cooling and storage method of this embodiment includes the step of placing the sample into 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 to perform programmed cooling of the sample, and after programmed cooling, the sample is directly stored in the liquid nitrogen storage box. The programmed cooling method includes the following steps.

[0049] The cooling process is divided into several stages that correspond to the standard ambient cooling curve and are executed sequentially. 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: Obtain the actual ambient temperature T1;

[0052] S3: Compare the target ambient temperature w with 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, then the sample will be lowered to the predetermined height.

[0054] If the target ambient temperature w is lower than the actual ambient temperature T1, then increase the predetermined height of the sample.

[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 this cooling stage.

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

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

[0058] The present invention discloses a sample cooling and storage method that divides the programmed cooling process into several stages corresponding to a standard environmental cooling curve. Each stage determines whether the sample needs to be cooled or cooled further by judging whether the actual environmental temperature T1 equals the target environmental temperature w, until the actual environmental temperature T1 matches the target environmental temperature w, until the actual environmental temperature T1 matches the target temperature T2 of that stage. After sequentially undergoing each stage of cooling, the sample finally reaches the temperature required for cryogenic storage and is directly stored in a liquid nitrogen storage container.

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

[0060] The liquid nitrogen storage box is used to store liquid nitrogen. It can be a stand-alone liquid nitrogen storage device or be installed inside a sample storage device.

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

[0062] In practice, multiple liquid nitrogen storage boxes are arranged around the rotating main shaft on the frame. Driven by the rotation drive device, the rotating main shaft drives the rotating frame to rotate so that the corresponding liquid nitrogen storage box is rotated directly below the transfer port, so that the subsequent lifting device can operate on the sample.

[0063] To improve insulation, the tank is a double-walled structure. Liquid nitrogen is stored inside the tank and then flows into a liquid nitrogen storage box through designated channels. Compared to the tank, the liquid nitrogen storage box has a smaller cross-section, resulting in virtually no temperature difference within the liquid nitrogen at the same level. In contrast, the tank itself, due to its larger volume, exhibits significant temperature differences at different locations at the same level, making it unsuitable for programmed cooling.

[0064] To facilitate lifting and lowering of single-layer samples, a basket-type sample storage rack is provided inside the liquid nitrogen storage tank. The basket-type sample storage rack is compatible with the liquid nitrogen storage box and includes a storage rack body 9. The top of the storage rack body is provided with a connector 10 that connects to the output end of the lifting device. The storage rack body has several layers of storage slots 11 with front openings arranged sequentially from top to bottom. A single-layer sample is placed in the storage slot.

[0065] In this embodiment, the origin is located 250 mm above the liquid surface inside the liquid nitrogen storage box. Figure 2 The graph shows the ambient temperature curve from the origin to 600 mm. As can be seen, from the origin to 250 mm, the ambient temperature changes little, remaining generally below -180℃. When the position increases from 250 mm to 600 mm, the ambient temperature rises from -180℃ to 5℃. The 600 mm position is located at the outlet of the transmission port. When the basket-type storage rack is lowered to its lowest point, the 22nd storage compartment is located at the origin.

[0066] The rotation drive device is used to drive the central axis to rotate, which in turn drives the frame and the liquid nitrogen storage box on it to rotate, so that the corresponding liquid nitrogen storage box rotates to the position directly below the transfer port, so that the lifting device can operate the basket-type storage rack and the sample on it.

[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 rotation center shaft. The reducer is a right-angle reducer, and its body is fixed on a fixing frame 14 on the surface of the can lid. The fixing frame is fixed on the surface of the can lid.

[0068] During operation, the output shaft of the drive motor drives the geared motor to rotate, which in turn drives the rotating central shaft at the output end of the geared motor to rotate.

[0069] Bearings are installed between the top of the rotating shaft and the can lid, and between the bottom of the rotating shaft and the bearing seat at the bottom of the can body, to reduce friction.

[0070] The top of the reducer output shaft is also connected to a turntable 15, and the surface of the turntable is marked with scales to facilitate the operator to observe the position of the rotating frame.

[0071] To limit the rotation of the frame, a baffle plate 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 baffle plate can pass through the U-groove of the U-shaped photoelectric switch.

[0072] The U-shaped photoelectric switch and the blocking plate limit the rotation of the rotating frame. Specifically, the turntable rotates under the drive of the reducer output shaft, which in turn drives the blocking plate on it to rotate. When the blocking plate rotates to the U-slot of the U-shaped photoelectric switch, the light path of the U-shaped photoelectric switch is blocked, thereby generating a corresponding pulse signal. The external control circuit can control the drive motor and reducer to stop rotating based on this pulse signal and issue a corresponding warning message to remind 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 frame plate and the bottom frame plate. The middle parts of the top frame plate and the bottom frame plate are respectively fixed to the rotating central axis. Both the top frame plate and the bottom frame plate are provided with several hollow holes to reduce their weight. The top 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 groove 22 adapted to the liquid nitrogen storage box to achieve positioning of the liquid nitrogen storage box.

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

[0075] In this embodiment, the lifting device is a servo motor-driven linear displacement actuator. The body of the linear displacement actuator is installed at the output end of the three-dimensional moving mechanism, which is located inside the housing 23 above the tank. A robotic arm is connected to the output end of the linear displacement actuator, and the robotic arm corresponds to the connecting piece at the top of the basket-type lifter.

[0076] During operation, the three-dimensional moving mechanism moves the lifting device above the transmission port. Then, the linear displacement driver, driven by the servo motor, drives the robotic arm and the basket-type storage rack connected to it to descend. After that, the external controller cools and saves the sample according to the above-mentioned cooling method. After saving, all components are reset, ready for the next operation.

[0077] In this embodiment, based on the standard ambient cooling curve, the programmed cooling is divided into five stages, each corresponding to... Figure 1 The five cooling segments a, b, c, d, and e of curve one are close to straight lines. The temperature control equations for each cooling segment are as follows:

[0078] w = Kx + b;

[0079] Where w is the set target ambient temperature, x is the cooling time, k is the cooling rate, and b is the starting temperature of the curve segment.

[0080] Step S1 involves setting 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 this stage of cooling, and corresponds to the aforementioned temperature control equation. Here, "real time" refers to a short interval, such as 1 second, and the specific time is determined based on the system's accuracy requirements.

[0081] The actual ambient temperature T1 in step S2 can be obtained by setting a temperature sensor at the location of the single-layer sample in 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 sample lifting can be a fixed height set manually, such as 1 cm, or it can be automatically set by the system according to the temperature gradient so that the sample can reach the actual ambient temperature as soon as possible.

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

[0084] During each stage of cooling, 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]

[0086] Where Δy is the output value of the PID algorithm; K P Here, s represents the proportional gain, b represents the proportional gain weight, w represents the target ambient temperature, x represents the actual ambient temperature of the sample, and K represents the proportional gain weight. i Let K be the integral action time, a be the differential delay coefficient, and K be the integral action time. d is the differential action time, and c is the differential action weight;

[0087] Among them, K P b, K i a, K d The specific value of 'c' is set manually or automatically by the system according to the accuracy and stability requirements.

[0088] By controlling the output of the servo motor through a PID algorithm, and then controlling the lifting and lowering of the basket-type storage rack and samples through a lifting device, precise lifting and lowering of samples can be achieved, thereby completing the programmed cooling.

[0089] In the PID algorithm, P refers to the proportional controller, I refers to the integral controller, and D refers to the derivative controller. In the proportional controller, the regulation law is that the output signal u of the controller is proportional to the deviation e (deviation e = set value w - process value x), and its equation is as follows.

[0090] u=K P e = K P (wx)

[0091] In a differential controller, the regulation law is that the deviation e (deviation e = setpoint w - process value x) is integrated by the integral controller to obtain the controller's output signal u, and its equation is as follows:

[0092]

[0093] In derivative control, the regulation law is that the deviation e, after being differentiated by the derivative controller, yields the controller's output signal u, which is the ratio of the control output u to the rate of change of the deviation. It is directly proportional, and its equation is as follows:

[0094]

[0095] Proportional, integral, and derivative controllers each have their advantages and disadvantages. In a temperature control system for basket-type cooling, using only one type of controller will not achieve the desired effect; all three need to be combined, i.e., the output of the control signal u = P + I + D, and K needs to be reasonably optimized. P K i K d And other relevant parameters. The final equation of the PID controller is as follows;

[0096]

[0097] Right now

[0098] The PID control equation is obtained by differentiating and limiting the above formula as follows:

[0099]

[0100] The above description is merely a preferred embodiment of the present invention, used to assist those skilled in the art in implementing the corresponding technical solutions, and is not intended to limit the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims. It should be noted that, for those skilled in the art, several equivalent improvements and modifications can be made based on the technical solutions of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Furthermore, it should be understood that although this specification describes the embodiments as described above, not every embodiment contains only one independent technical solution. This descriptive method is merely for clarity. Those skilled in the art should consider 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 into a liquid nitrogen storage box, characterized in that: The sample cooling and storage method involves raising and lowering the sample within the liquid nitrogen storage box using a lifting device to perform programmed cooling, and then directly storing the sample in the liquid nitrogen storage box after programmed cooling. The liquid nitrogen storage box is installed in the sample storage device. The process of cooling down includes the following steps; The cooling process is divided into several stages that correspond to the standard ambient cooling curve and are executed sequentially. 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: Obtain the actual ambient temperature T1; S3: Compare the target ambient temperature w with 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, then the sample will be lowered to the predetermined height. If the target ambient temperature w is lower than the actual ambient temperature T1, then increase the predetermined height of the sample. 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 this cooling stage. If the actual ambient temperature T1 is equal to the target temperature T2 for this cooling stage, then the cooling stage ends. If the actual ambient temperature T1 is not equal to the target temperature T2 for cooling in this stage, then repeat steps S1 to S3 until the actual ambient temperature T1 is equal to the target temperature T2 for cooling in this stage. During each stage of cooling, 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; ； Where Δy is the output value of the PID algorithm; K P Here, s represents the proportional gain, b represents the proportional gain weight, w represents the target ambient temperature, x represents the actual ambient temperature of the sample, and K represents the proportional gain weight. i Let K be the integral action time, a be the differential delay coefficient, and K be the integral action time. d is the differential action time, c is the differential action weight; the lifting device is a linear displacement actuator driven by a servo motor; the liquid nitrogen storage box is set in the sample storage device, the sample storage device includes a tank, the top of the tank is provided with a tank cover, the inner cavity of the tank is provided with a rotating frame, the rotating frame includes a frame and a rotating main shaft connected to the frame, the bottom end of the rotating main shaft is provided on a bearing seat at the center of the bottom of the tank, 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, 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; The liquid nitrogen storage box is a cuboid box with an open top, and multiple liquid nitrogen storage boxes are arranged on the frame around the main axis of rotation. The liquid nitrogen storage tank is equipped with a basket-type sample storage rack, which is compatible with the liquid nitrogen storage box. The basket-type sample storage rack includes a storage rack body, and the top of the storage rack body is provided with a connector that connects to the output end of the lifting device. The storage rack body has several layers of storage slots with front openings from top to bottom, and a single layer of sample is placed in the storage slot.

2. The method for cooling and storing samples according to claim 1, characterized in that: The origin is located 250 mm above the liquid surface inside the liquid nitrogen storage box.

3. The method for cooling and storing samples according to claim 2, 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, and the output shaft of the reducer is connected to the rotation central shaft. The reducer is a right-angle reducer, and its body is fixed on a fixed frame on the surface of the can lid. The fixed frame is fixed on the surface of the can lid.

4. The method for cooling and storing samples according to claim 3, characterized in that: Bearings are installed between the top of the rotating central shaft and the can lid, and between the bottom of the rotating central shaft and the bearing seat at the bottom of the can body.

5. The method for cooling and storing samples according to claim 3, characterized in that: A turntable is also connected to the top of the output shaft of the reducer.

6. The method for cooling and storing samples according to claim 5, characterized in that: The turntable is equipped with a shielding plate, and 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 a fixed frame. The shielding plate can pass through the U-groove of the U-shaped photoelectric switch.

7. The method for cooling and storing samples according to claim 1, characterized in that: 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. The middle part of the top frame plate and the middle part of the bottom frame plate are respectively fixedly connected to the rotation axis.

8. The method for cooling and storing samples according to claim 7, characterized in that: The top of the liquid nitrogen storage box is bolted to the edge of the top frame plate, 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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