Self-stability-maintaining biological liquid nitrogen device and method

Abstract

The invention belongs to the technical field of biological sample freezing, and mainly relates to a self-stability-maintaining biological liquid nitrogen tank device which comprises a biological liquid nitrogen tank, a conveying device and a cooling capacity circulating device used for re-condensing nitrogen in the biological liquid nitrogen tank. Wherein a bottom plate is arranged at a tank opening of the biological liquid nitrogen tank, and a conveying device is arranged at a tank body; the bottom plate is used for bearing the bottom of a tank opening pipe picking area of the biological liquid nitrogen tank, a heat exchange device is arranged on one side in the thickness direction, and the heat exchange device is connected with the cooling capacity circulating device through a pipeline; the conveying device is communicated with the inner cavity of the biological liquid nitrogen tank and used for being communicated with the nitrogen supply device; and the cooling capacity circulating device is connected with the inner cavity of the biological liquid nitrogen tank through a metal pipeline. Through the self-stability-maintaining design, after liquid nitrogen is introduced into the liquid nitrogen tank, liquid nitrogen does not need to be supplemented, and meanwhile the temperature of a tank opening is controlled; meanwhile, the invention further relates to a self-stability-maintaining method of the biological liquid nitrogen device, and the cryopreservation effect of the biological liquid nitrogen tank is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of biological sample freezing, and mainly relates to a self-stabilizing biological liquid nitrogen device and method. Background Art

[0002] In the fields of biomedicine, life sciences, genetic engineering, etc., a large number of biological samples need to be stored at low temperatures for a long time to ensure their activity and stability. Liquid nitrogen tanks have become important equipment for preserving biological samples (such as cells, tissues, blood, DNA samples, etc.) because they can provide an ultra-low temperature environment close to -196°C. Preserving samples in liquid nitrogen tanks can effectively prevent samples from degrading or losing activity over a long period of time. Therefore, liquid nitrogen tanks are widely used in scientific research laboratories, hospitals, biological sample banks, and other occasions.

[0003] At present, liquid nitrogen tanks on the market usually rely on external liquid nitrogen replenishment to maintain the low temperature environment in the tank. These devices will encounter many technical problems during operation. For example, during the storage process, liquid nitrogen will inevitably evaporate gradually due to heat infiltration and the influence of external temperature, resulting in a decrease in the amount of liquid nitrogen in the tank and an increase in temperature, which in turn affects the safety of biological samples. The evaporated nitrogen is usually discharged to the outside and is difficult to recycle; in addition, in order to maintain the low temperature environment in the liquid nitrogen tank, operators need to replenish liquid nitrogen regularly, which not only increases the complexity of operation, but also brings high costs for the use of liquid nitrogen. In addition, interruptions in the supply of liquid nitrogen or untimely replenishment may cause the sample temperature to get out of control, which in turn has an adverse effect on the quality of the sample.

[0004] In the relevant technical field, there are some liquid nitrogen tank technologies that attempt to solve the problems of liquid nitrogen evaporation loss and temperature stability in the tank. For example, CN106081363B discloses a biological sample storage device with zero liquid nitrogen loss, which reduces the volatilization of liquid nitrogen by condensing nitrogen. However, this technology still has deficiencies in terms of automation and nitrogen recycling, and cannot achieve efficient reliquefaction of nitrogen, and lacks precise control means for the tank mouth temperature.

[0005] Based on this, there is an urgent need for a self-stabilizing biological liquid nitrogen device and method to solve the above technical defects. Summary of the invention

[0006] One of the purposes of the present invention is to provide a self-maintaining biological liquid nitrogen device to address the deficiencies of the prior art, thereby solving the technical problem that the prior art cannot achieve efficient liquefaction of nitrogen and temperature control of the tank port.

[0007] In order to achieve the above-mentioned invention objectives, this application implements the following technical solutions:

[0008] A self-stabilizing biological liquid nitrogen device comprises: a biological liquid nitrogen tank, a conveying device for filling the biological liquid nitrogen tank with liquid nitrogen, and a cold circulation device for recondensing nitrogen in the biological liquid nitrogen tank;

[0009] Among them, the biological liquid nitrogen tank is provided with a bottom plate at the tank mouth and a conveying device at the tank body;

[0010] The bottom plate is used to bear the bottom weight of the tank mouth pipe extension area of ​​the biological liquid nitrogen tank. A heat exchange device is provided on one side in the thickness direction. The heat exchange device is connected to the cold circulation device through a pipeline.

[0011] A conveying device is communicated with the inner cavity of the biological liquid nitrogen tank and is used to connect to a nitrogen supply device, and the nitrogen supply device is used to provide liquid nitrogen;

[0012] The cold circulation device is connected to the inner cavity of the biological liquid nitrogen tank through a metal pipeline.

[0013] The above technical solution produces at least the following technical effects:

[0014] This application fully considers the property that liquid nitrogen will evaporate into nitrogen gas after being heated (because the density of nitrogen gas is lower than that of liquid nitrogen, and it absorbs heat during the evaporation process, resulting in a relatively high temperature, so the nitrogen gas will rise to the top area of ​​the liquid nitrogen tank, that is, near the tank mouth). In the traditional liquid nitrogen tank design, these nitrogen gases usually accumulate in the tank mouth area and eventually dissipate into the external environment, resulting in the loss of liquid nitrogen. Furthermore, this application installs a bottom plate in the pipe-lifting area of ​​the biological liquid nitrogen tank, and connects the heat exchange device in the bottom plate with the liquid nitrogen circulation system, so that the cold energy is directly transferred to the tank mouth area, thereby quickly liquefying the nitrogen gas floating at the tank mouth.

[0015] This design not only reduces the loss of nitrogen, but also greatly shortens the liquefaction time and improves the operating efficiency of the liquid nitrogen tank. In addition, the bottom plate of the liquid nitrogen tank mouth not only serves as the main carrier of cold conduction, but also as a load-bearing plate in the pipe picking area. When the pipe is picked up at the tank mouth, the bottom plate can maintain the low temperature of the tank mouth area, prevent the ambient temperature from rising instantly when the sample is taken out, and ensure the safety of the sample.

[0016] As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, the heat exchange device is a cold screen with fins and a copper tube, the input end of the heat exchange device is connected to one end of the pipeline, and the output end of the heat exchange device is connected to the other end of the pipeline.

[0017] As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, the copper tube is an annular tube, and the cold shield with fins is connected to the copper tube by welding or crimping.

[0018] As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, a temperature sensor is provided in the tank opening and / or the inner cavity of the biological liquid nitrogen tank; the temperature sensor is electrically connected to the control terminal;

[0019] The control terminal is electrically connected to the cold circulation device, and controls the start and stop of the cold circulation device according to whether the data monitored by the temperature sensor reaches a first threshold.

[0020] As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, a liquid level sensor is provided in the inner cavity of the biological liquid nitrogen tank;

[0021] The control terminal controls the start and stop of the cold circulation device according to whether the data monitored by the liquid level sensor reaches a second threshold value.

[0022] As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, the control terminal includes a display for displaying temperature data and liquid level data of the biological liquid nitrogen tank.

[0023] As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, the surface of the bottom plate on one side facing the inner cavity of the biological liquid nitrogen tank is covered with a polymer hydrophobic coating.

[0024] As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, the cold circulation device includes a refrigerator;

[0025] The refrigerator is a Stirling refrigerator, which performs heat exchange at different temperatures at the input end and the output end, wherein the metal pipeline is connected to the input end and the output end of the Stirling refrigerator respectively.

[0026] As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, the cold circulation device also includes an expander and a capillary tube.

[0027] The second purpose of the present invention is to provide a method for self-stabilization of a biological liquid nitrogen tank in view of the shortcomings of the prior art, so as to solve the technical defect that the prior art cannot realize efficient self-stabilization control of the biological liquid nitrogen tank.

[0028] In order to achieve the above technical objectives, this application implements the following technical solutions:

[0029] A method for self-stabilizing a biological liquid nitrogen tank, comprising any of the self-stabilizing biological liquid nitrogen devices described above, and the steps are as follows:

[0030] S101, supplying initial liquid nitrogen to the biological liquid nitrogen tank through a conveying device, and confirming according to the display that the liquid nitrogen in the biological liquid nitrogen tank reaches the initial temperature and liquid level requirements;

[0031] S201, when the temperature sensor detects that the temperature at the mouth of the biological liquid nitrogen tank or in the cavity has risen to a first threshold, a signal for controlling the start of the cold circulation device is sent to the control terminal;

[0032] The cold circulation device condenses the nitrogen in the biological liquid nitrogen tank, and cools the tank opening of the biological liquid nitrogen tank by passing the condensed liquid nitrogen through the heat exchange device;

[0033] S301, when the temperature sensor detects that the temperature at the mouth of the biological liquid nitrogen tank or in the cavity drops below a first threshold, a signal is sent to the control terminal to control the refrigeration circulation device to shut down;

[0034] S401, when the liquid level sensor detects that the liquid nitrogen level in the biological liquid nitrogen tank drops to a second threshold, a signal for controlling the start of the cold circulation device is sent to the control terminal;

[0035] The cold circulation device condenses the nitrogen in the biological liquid nitrogen tank and returns the liquid nitrogen to the tank through the metal pipeline;

[0036] S501. When the liquid level sensor detects that the liquid nitrogen level in the biological liquid nitrogen tank rises above a second threshold, a signal for controlling the refrigeration circulation device to be closed is sent to the control terminal.

[0037] The above technical solution produces at least the following technical effects:

[0038] The biological liquid nitrogen tank self-stabilization method provided by the present invention realizes real-time monitoring and precise control of the temperature and liquid level in the biological liquid nitrogen tank, thereby ensuring the stability and safety of biological samples during storage. The specific technical effects are as follows:

[0039] The above technical solution of this application can timely detect the changes of temperature and liquid level in the biological liquid nitrogen tank through real-time monitoring of temperature sensors and liquid level sensors, so as to quickly respond and start or shut down the cold circulation device, effectively avoiding damage to biological samples caused by abnormal temperature or liquid level. At the same time, the control terminal of this application is integrated with a display, which can intuitively display the temperature data and liquid level data of the biological liquid nitrogen tank, making it convenient for operators to grasp the status of the tank in real time and make timely adjustments and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0041] Figure 1 This is a schematic diagram of the structure of Example 1 of the present invention;

[0042] Figure 2 This is a flow chart of Example 1 of the present invention;

[0043] Figure 3 This is a schematic diagram of the structure of a heating device according to Example 1 of the present invention;

[0044] Figure 4 This is a flow chart of Example 2 of the present invention;

[0045] Figure 5 It is a schematic structural diagram of a refrigeration circulation device according to Example 3 of the present invention;

[0046] in:

[0047] 1- Biological liquid nitrogen tank;

[0048] 11- bottom plate;

[0049] 111- heat exchange device;

[0050] 12- Temperature sensor;

[0051] 13-Liquid level sensor;

[0052] 2- conveying device;

[0053] 3- Refrigeration circulation device;

[0054] 31-Pipeline;

[0055] 32-Metal pipeline;

[0056] 33-Refrigerator;

[0057] 34- expander;

[0058] 35-capillary;

[0059] 4- Nitrogen supply device;

[0060] 5-Control terminal;

[0061] 51-Display. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0063] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the claims. Any technical personnel in this field may make several possible changes and modifications without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

[0065] The present invention is further described in detail below in conjunction with specific implementation methods, but the embodiments of the present invention are not limited thereto.

[0066] Example 1

[0067] It is known that liquid nitrogen evaporates after being heated to produce nitrogen. The density of nitrogen is smaller than that of liquid nitrogen, and because it absorbs a certain amount of heat when evaporating, the temperature is relatively high, so the nitrogen will rise to the top area of ​​the liquid nitrogen tank, that is, the tank mouth. In traditional liquid nitrogen tanks, these nitrogens usually float in the tank mouth area and eventually escape to the outside, causing the loss of liquid nitrogen. In the prior art, the nitrogen at the tank mouth is difficult to quickly condense into liquid nitrogen because it is far away from the low-temperature liquid nitrogen in the tank and is easily heated by contact with the outside air. Therefore, the nitrogen floats in the tank mouth area for a long time, increasing the volatilization loss.

[0068] In the prior art, patent number CN106081363B describes a liquid nitrogen zero-loss biological sample storage device, the core innovation of which is to re-liquefy nitrogen into liquid nitrogen through a condensing heat exchanger and a Stirling refrigerator, thereby achieving zero loss of liquid nitrogen. The main advantage of this design is that it reduces the consumption of liquid nitrogen and ensures the long-term preservation of biological samples without frequent replenishment of liquid nitrogen. However, it does not solve the problem of nitrogen floating at the mouth of the tank, but only extracts and processes the nitrogen in the inner cavity of the tank through a condensing heat exchanger.

[0069] So according to the above principle, if Figure 1-3 As shown, in order to solve the above technical defects, the present application specifically provides a self-stabilizing biological liquid nitrogen device, including: a biological liquid nitrogen tank 1, a conveying device 2 for filling the biological liquid nitrogen tank 1 with liquid nitrogen, and a cold circulation device 3 for recondensing the nitrogen in the biological liquid nitrogen tank 1.

[0070] Furthermore, the biological liquid nitrogen tank 1 is provided with a bottom plate 11 at the tank mouth, and a conveying device 2 is provided at the tank body; the bottom plate 11 is used to bear the bottom of the tank mouth pipe area of ​​the biological liquid nitrogen tank 1, and a heat exchange device 111 is provided on one side in the thickness direction, and the heat exchange device 111 is connected to the cold circulation device 3 through a pipe 31. Among them, the cold circulation device 3 directly transmits the cold to the heat exchange device 111 through the pipe 31. The setting of the heat exchange device 111 enables the nitrogen at the tank mouth to quickly contact the low-temperature heat exchange surface. After the nitrogen is cooled to -196°C at the tank mouth, it is immediately liquefied into liquid nitrogen and quickly refluxed into the tank. This design greatly shortens the time from evaporation to reliquefaction of nitrogen and reduces the volatilization loss of nitrogen. Moreover, since the temperature of the tank mouth bottom plate 11 is extremely low, nitrogen does not need to float at the tank mouth for a long time waiting for natural condensation, and the liquefaction process is significantly accelerated. The rapid liquefaction and reflux of liquid nitrogen reduce the chance of nitrogen escaping to the outside world and improve the overall efficiency of the system. In addition, the tank mouth bottom plate 11 is made of a high thermal conductivity material (such as aluminum alloy or copper), thereby increasing the supporting force of the bottom plate 11 and further alleviating the load-bearing pressure of the tank mouth pipe extension area.

[0071] Furthermore, the conveying device 2 is in communication with the inner cavity of the biological liquid nitrogen tank 1, and is used to connect to the nitrogen supply device 4; the nitrogen supply device 4 is used to provide liquid nitrogen. The conveying device 2 includes a pipeline connected to the nitrogen supply device 4 and a pipeline in communication with the inner cavity of the biological liquid nitrogen tank 1, which is used to transport liquid nitrogen from the nitrogen supply device 4 to the biological liquid nitrogen tank 1. The conveying device 2 also includes at least one control valve, which can automatically adjust the delivery amount of liquid nitrogen according to the temperature and liquid level data in the biological liquid nitrogen tank 1 to ensure the stability of the environment in the tank.

[0072] Furthermore, the cold circulation device 3 is connected to the inner cavity of the biological liquid nitrogen tank 1 through a metal pipe 32, thereby realizing the extraction and treatment of nitrogen in the cavity of the biological liquid nitrogen tank 1. In the specific implementation process, the metal pipe 32 can be a gravity siphon, which uses gravity to introduce the condensed nitrogen into the tank without the need for external power. The gravity siphon can be made of a low-temperature resistant non-metallic material (such as PTFE), which can withstand the deep low temperature environment of liquid nitrogen and has sufficient flexibility.

[0073] Furthermore, the heat exchange device 111 is a cold screen with fins and a copper tube, the input end of the heat exchange device 11 is connected to one end of the pipeline, and the output end of the heat exchange device 111 is connected to the other end of the pipeline. One end of the pipeline 31 is used to transport the cold energy generated by the cold energy circulation device 3 to the heat exchange device 111, and the other end of the pipeline 31 is used to transport the nitrogen cooled by the heat exchange device 111 back to the biological liquid nitrogen tank 1. Through this design, it can be ensured that the nitrogen will not escape into the external environment before being condensed into liquid nitrogen, thereby further reducing the loss of liquid nitrogen.

[0074] In actual operation, a dense cold screen with fins is laid on the bottom surface of the bottom plate 11 of the liquid nitrogen tank mouth, and is connected to the copper pipe pipeline. Coolant circulates in the copper pipe, and its distribution is annular, which can evenly cover the entire tank mouth area. The cold energy of the cold circulation device 3 is first transmitted through the copper pipe, and then diffused to the inside of the liquid nitrogen tank through the cold screen with fins to ensure the consistency of the temperature at the bottom of the tank mouth. In addition, unlike the traditional single condenser structure, the use of a double-layer heat exchange structure (including fins and copper pipes) can extend the path of cold energy transfer and increase the heat dissipation area, thereby further improving the efficiency of cold energy transmission.

[0075] Specifically, the tube picking area usually refers to a specific area in a liquid nitrogen tank or a biological sample freezing device, which is mainly used for accessing biological samples. In a liquid nitrogen tank, samples are generally stored in freezing tubes or freezing racks, and the tube picking area is the working area where operators take out or put back freezing tubes. In actual operation, the improvement of the base plate 11 in the present application allows operators to take out or put back freezing tubes or freezing racks stored in the tank in the tube picking area, while ensuring that the stability of the low-temperature environment in the tank is not significantly affected. In actual operation, the liquid nitrogen tank mouth base plate 11 is usually installed at the bottom of the liquid nitrogen tank mouth as a load-bearing and heat exchange component. It must be firmly connected to the liquid nitrogen tank mouth through a sealing ring fastening device (such as bolts, buckles or other locking structures) to ensure that the low-temperature environment in the tank is not disturbed by the outside world and maintain efficient heat exchange performance. In order to facilitate maintenance or replacement, it is an ideal choice to design the base plate 11 to be detachable. However, in most cases, the base plate 11 will remain fixed and will only be disassembled when maintenance or special operations are required. In addition, the joint between the bottom plate 11 and the tank opening is usually designed with an efficient sealing structure to prevent cold air leakage and external gas intrusion. This can be achieved by using an elastic sealing ring or a composite sealing gasket, while ensuring that the integrity of the seal is maintained in the closed or operating state.

[0076] Furthermore, the copper tube in the above-mentioned heating device is an annular tube, and the cold screen with fins is connected to the copper tube by welding or crimping. During the specific implementation of the case, in order to ensure the stability and durability of the heating device, the connection between the copper tube and the cold screen with fins adopts a welding process to ensure a close connection between the two. The welding process not only improves the heat exchange efficiency, but also ensures that there will be no loosening or leakage during long-term operation.

[0077] During the use of the liquid nitrogen tank, operators in the tube picking area need to frequently perform sample storage and retrieval operations. In order to ensure the safety of the operators, the present application designs an anti-skid structure on the surface of the bottom plate 11 of the liquid nitrogen tank mouth, such as an uneven surface or an anti-skid coating, to reduce the risk of operators slipping when performing tube picking operations. At the same time, in order to prevent operators from directly contacting the low-temperature surface and causing frostbite, the surface of the bottom plate 11 is also covered with a layer of insulating material, such as a polytetrafluoroethylene (PTFE) coating, which not only ensures heat exchange efficiency but also improves operational safety.

[0078] Furthermore, the surface of the bottom plate 11 facing the inner cavity of the biological liquid nitrogen tank 1 is covered with a polymer hydrophobic coating. The hydrophobic coating design prevents liquid nitrogen from accumulating on the bottom plate 11, ensures efficient conduction of cold, and avoids local overcooling caused by liquid nitrogen accumulation in traditional liquid nitrogen tanks.

[0079] In summary, the above technical solution has made further improvements to the self-maintaining stability of the biological liquid tank, including the structural optimization of the bottom plate 11 of the liquid nitrogen tank mouth, the innovative design of the heat exchange device 111 and the control of the conveying device 2. These improvements have significantly improved the storage efficiency and operational safety of liquid nitrogen.

[0080] Example 2

[0081] like Figure 1-4 As shown, the difference from Example 1 is that: the present application aims to further enhance the control effect of the self-stabilization treatment of liquid nitrogen. Furthermore, a temperature sensor 12 is provided in the tank mouth and / or the inner cavity of the biological liquid nitrogen tank 1; the temperature sensor 12 is electrically connected to the control terminal 5. In the specific implementation process, the temperature sensor 12 is provided at the tank mouth because the liquid nitrogen will float directly at the tank mouth after vaporization, and when the liquid nitrogen in the tank body vaporizes to a certain amount, the temperature change can also be detected in the cavity of the biological liquid tank. The control terminal 5 automatically adjusts the working state of the cold circulation device 3 according to the data provided by the temperature sensor 12 to ensure that the temperature of the tank mouth area remains within the set range. (In the specific implementation process, the control terminal 5 can be a microprocessor or a computer system with data processing and control functions) In this way, the system can monitor and adjust the working parameters of the cold circulation device 3 in real time, thereby realizing precise control of the tank mouth temperature.

[0082] Furthermore, in order to improve the response speed and control accuracy of the system, the temperature sensor 12 can use a highly sensitive thermocouple or thermal resistor. These sensors can quickly respond to temperature changes and transmit data to the control terminal 5. The control terminal 5 calculates the optimal working state of the cold circulation device 3 through an algorithm based on the received temperature data to ensure the temperature stability of the tank mouth area. When the temperature sensor 12 detects that the temperature in the tank mouth area rises, the control terminal 5 will instruct the cold circulation device 3 to increase the cold output, thereby quickly reducing the temperature in the tank mouth area; conversely, when the temperature sensor 12 detects that the temperature in the tank mouth area is too low, the control terminal 5 will reduce the cold output to avoid energy waste caused by overcooling.

[0083] Furthermore, the control terminal 5 is electrically connected to the cold circulation device 3, and controls the start and shut down of the cold circulation device 3 according to whether the data monitored by the temperature sensor 12 reaches the first threshold. In the specific implementation process, when it is detected that the tank mouth temperature rises to a preset first threshold (for example, -190°C, it should be noted in this application that the first threshold is a temperature value rather than an absolute value, that is, when the temperature is greater than -190°C (such as -189°C), it is judged to exceed the first threshold or be greater than the first threshold), the control terminal 5 will activate the cold circulation device 3 to refrigerate and condense nitrogen, and at the same time transfer the cold to the tank mouth through the heat exchange copper tube in the heat exchange device 111. Once the tank mouth temperature falls back to the set safety range (for example, around -196°C), the control terminal 5 will shut down the liquid nitrogen circulation system and the heat exchange equipment it controls, thereby achieving energy saving.

[0084] Furthermore, a liquid level sensor 13 is provided in the inner cavity of the biological liquid nitrogen tank 1; specifically, the control terminal 5 controls the start and stop of the cold circulation device 3 according to whether the data monitored by the liquid level sensor 13 reaches the second threshold. In the specific implementation process, when the liquid level sensor 13 detects that the liquid nitrogen level drops to the preset second threshold (for example, 70% of the tank height), the control terminal 5 will start the cold circulation device 3 to replenish it to ensure sufficient supply of liquid nitrogen. The liquid level sensor 13 usually adopts an ultrasonic or capacitive sensor, which can accurately measure the liquid level height in the liquid nitrogen tank. The control terminal 5 automatically adjusts the supply of liquid nitrogen according to the data provided by the liquid level sensor 13 to maintain the stability of the liquid level in the liquid nitrogen tank.

[0085] Furthermore, in order to ensure the efficient operation of the cold circulation device 3, the control terminal 5 also has a fault diagnosis function. In the specific implementation process, the control terminal 5 will monitor the working parameters of the cold circulation device 3, such as pressure, flow rate and temperature, in real time. Once abnormal data is found, the control terminal 5 will immediately issue an alarm and automatically execute fault handling measures according to a preset program, such as switching to a backup system, adjusting working parameters or stopping equipment operation. This can effectively avoid liquid nitrogen supply interruptions caused by equipment failures and ensure the safe storage of biological samples. As a further improvement to the self-stabilizing biological liquid nitrogen device of the present invention, the control terminal 5 includes a display 51 for displaying temperature data and liquid level data of the biological liquid nitrogen tank 1.

[0086] Specifically, the display 51 can also be used for the real-time monitoring of the initial nitrogen supply data of the biological liquid nitrogen tank 1 by the nitrogen supply device 4 through the transmission device, and the real-time display of the working state of the cold circulation device 3. Through this design, the operator can conveniently view the current temperature and liquid level data, as well as the working state of the cold circulation device 3, so as to better understand the operation of the biological liquid nitrogen tank 1.

[0087] Furthermore, the control terminal 5 also has a remote communication function. Through the Internet or a dedicated network, the control terminal 5 can transmit the temperature data, liquid level data of the biological liquid nitrogen tank 1 and the working status of the cold circulation device 3 to the remote monitoring center in real time. In this way, the management personnel can monitor the operation of the biological liquid nitrogen tank 1 in real time in the office or any place with network coverage, and find and deal with problems in time.

[0088] The other details that are the same as those in Example 1 are not described in detail in this example.

[0089] Example 3

[0090] like Figure 1-5 As shown, different from Example 1, in order to further illustrate the working principle of the nitrogen condensation and heat exchange device 111 of the present application for cooling the tank mouth, specifically, the cold circulation device 3 of the present application includes a refrigerator 33;

[0091] Further, the refrigerator 33 is a Stirling refrigerator 33, which performs heat exchange at different temperatures at the input end and the output end, wherein the metal pipe 32 is connected to the input end and the output end of the Stirling refrigerator 33 respectively. Among them, the working principle of the Stirling refrigerator 33 is: heat is exchanged between two different temperature ends through the compression and expansion of the gas. The compression heating and expansion cooling processes of this gas are relatively balanced and alternately carried out. Specifically: the gas (nitrogen in this application) is compressed at the compression end, the volume decreases, and the temperature rises. The increased temperature causes the gas to transfer heat to the external environment or the regenerator (heat exchange device), so that when the gas enters the expansion end in the next cycle, the temperature drops. The gas expands at the expansion end, the volume increases, and the temperature drops. At this time, the gas absorbs heat from the surrounding environment to achieve cooling. The expanded gas can reach a lower temperature and transfer the cold to the liquid nitrogen tank or other cooling targets.

[0092] Among them, the regenerator in the Stirling refrigerator 33 is a very important component, which is used to store the heat released when the gas is compressed and return the heat to the system when the gas expands. The presence of the regenerator makes the Stirling cycle more efficient and reduces energy waste. Therefore, compared with the existing traditional liquid nitrogen tanks and automated biological sample libraries, the biological sample storage device in the present invention, equipped with the above-mentioned Stirling refrigerator 33, can directly introduce the cold in the 77k temperature zone into the biological sample library, directly providing a cold source for the biological sample library.

[0093] Furthermore, the cold cycle device 3 also includes an expander 34 and a capillary tube 35; specifically, the expander 34 is connected to the refrigerator 33 through the capillary tube 35. In the specific implementation process, although the expansion container is not a necessary component of the Stirling refrigerator 33, it can provide more space for the expansion of the gas and optimize the expansion process. The function of the expander 34 is to improve the efficiency and stability of the gas expansion, but in general, the Stirling refrigerator 33 can complete the compression and expansion cycle by relying on the internal piston system.

[0094] In addition, the capillary tube 35 and the expander 34 play an important role in regulating the nitrogen flow rate and controlling the expansion and compression cycle in the operation of the Stirling refrigerator 33. They work together in the entire condensation and reuse process to ensure that the gas flows smoothly, the pressure is properly controlled, and the condensation efficiency is improved. Among them, the capillary tube 35 is directly connected to the Stirling refrigerant, which can control the flow rate and pressure of the gas entering the refrigerator 33, ensuring that the nitrogen enters the condensation system at a stable speed and appropriate pressure. The expander 34 acts on the rear end of the capillary tube 35, further assisting the expansion, cooling and condensation of the gas, helping to control the volume and temperature of the gas after expansion, so that the nitrogen quickly reaches the liquefaction condition after expansion.

[0095] The other details that are the same as those in Example 1 are not described in detail in this example.

[0096] Example 4

[0097] like Figure 1-5 As shown, different from Examples 1-3, in order to further improve the self-stabilization control of the biological liquid nitrogen tank 1 of the present application, the present application designs a method for self-stabilization of the biological liquid nitrogen tank 1, including any of the above-mentioned self-stabilizing biological liquid nitrogen devices, and the steps are as follows:

[0098] S101, supplying initial liquid nitrogen to the biological liquid nitrogen tank 1 through the conveying device 2, and determining whether the liquid nitrogen in the biological liquid nitrogen tank 1 reaches the initial temperature and liquid level requirements according to the display 51; in the specific implementation process, this step can be performed automatically or manually. In the automatic mode, the conveying device 2 automatically opens according to the preset program and injects liquid nitrogen into the biological liquid nitrogen tank 1 until the display 51 shows that the initial temperature and liquid level are reached. The manual mode requires the operator to manually control the switch of the conveying device 2 according to the instructions of the display 51 to ensure the injection amount of liquid nitrogen.

[0099] S201, when the temperature sensor 12 detects that the temperature at the mouth or in the cavity of the biological liquid nitrogen tank 1 rises to a first threshold, a signal for controlling the refrigeration circulation device 3 to start is sent to the control terminal 5;

[0100] The cold circulation device 3 condenses the nitrogen in the biological liquid nitrogen tank 1, and cools the tank opening of the biological liquid nitrogen tank 1 by passing the condensed liquid nitrogen through the heat exchange device 111;

[0101] S301, when the temperature sensor 12 detects that the temperature at the tank opening or in the cavity of the biological liquid nitrogen tank 1 drops below a first threshold, a signal is sent to the control terminal 5 to control the refrigeration circulation device 3 to be turned off;

[0102] S401, when the liquid level sensor 13 detects that the liquid nitrogen level in the biological liquid nitrogen tank 1 drops to the second threshold, a signal for controlling the refrigeration circulation device 3 to start is sent to the control terminal 5; the refrigeration circulation device 3 condenses the nitrogen in the biological liquid nitrogen tank 1 and returns the liquid nitrogen to the tank through the metal pipe 32;

[0103] S501. When the liquid level sensor 13 detects that the liquid nitrogen level in the biological liquid nitrogen tank 1 rises above the second threshold, a signal for controlling the refrigeration circulation device 3 to be closed is sent to the control terminal 5.

[0104] In the above steps, through the cyclic operation of steps S201-S501, the biological liquid nitrogen tank 1 can achieve self-stabilizing control of temperature and liquid level, ensuring that the biological samples can be stored for a long time under the best storage conditions.

[0105] Furthermore, in order to improve the stability and reliability of the system, this embodiment also introduces a fault detection and alarm mechanism. Specifically, the control terminal 5 has a built-in intelligent diagnostic program that can monitor the working status of key components such as the cold circulation device 3, the temperature sensor 12, and the liquid level sensor 13 in real time. Once an abnormal situation is detected, such as sensor failure, abnormal operation of the cold circulation device 3, etc., the control terminal 5 will immediately issue an alarm signal and notify the management personnel through the remote communication function. The management personnel can quickly take corresponding measures, such as dispatching maintenance personnel for on-site inspection and maintenance, to ensure the normal operation of the biological liquid nitrogen tank 1.

[0106] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A self-stabilizing biological liquid nitrogen device, comprising: A biological liquid nitrogen tank (1), a conveying device (2) for filling the biological liquid nitrogen tank (1) with liquid nitrogen, and a cold circulation device (3) for recondensing nitrogen in the biological liquid nitrogen tank (1), characterized in that: The biological liquid nitrogen tank (1) is provided with a bottom plate (11) at the tank mouth and a conveying device (2) at the tank body; The bottom plate (11) is used to bear the bottom weight of the tank mouth pipe extension area of ​​the biological liquid nitrogen tank (1), and a heat exchange device (111) is provided on one side in the thickness direction, and the heat exchange device (111) is connected to the cold circulation device (3) through a pipeline (31); The conveying device (2) is in communication with the inner cavity of the biological liquid nitrogen tank (1) and is used to be connected to a nitrogen supply device (4), and the nitrogen supply device (4) is used to provide liquid nitrogen; The cold circulation device (3) is connected to the inner cavity of the biological liquid nitrogen tank (1) via a metal pipeline (32).

2. A self-stabilizing biological liquid nitrogen device according to claim 1, characterized in that: The heat exchange device (111) is a cold screen with fins and a copper tube. The input end of the heat exchange device (111) is connected to one end of the pipeline (31), and the output end of the heat exchange device (111) is connected to the other end of the pipeline (31).

3. A self-stabilizing biological liquid nitrogen device according to claim 2, characterized in that: The copper tube is an annular tube, and the cold shield with fins is connected to the copper tube by welding or crimping.

4. A self-stabilizing biological liquid nitrogen device according to any one of claims 1 to 3, characterized in that: A temperature sensor (12) is provided in the tank opening and / or the inner cavity of the biological liquid nitrogen tank (1); the temperature sensor (12) is electrically connected to the control terminal (5); The control terminal (5) is electrically connected to the cold circulation device (3) and controls the start and stop of the cold circulation device (3) according to whether the data monitored by the temperature sensor (12) reaches a first threshold value.

5. A self-stabilizing biological liquid nitrogen device according to claim 4, characterized in that: A liquid level sensor (13) is provided in the inner cavity of the biological liquid nitrogen tank (1); The control terminal (5) controls the start and stop of the cold circulation device (3) according to whether the data monitored by the liquid level sensor (13) reaches a second threshold value.

6. A self-stabilizing biological liquid nitrogen device according to claim 5, characterized in that: The control terminal (5) comprises a display (51) for displaying temperature data and liquid level data of the biological liquid nitrogen tank (1).

7. A self-stabilizing biological liquid nitrogen device according to claim 1, characterized in that: The surface of the bottom plate (11) on the side facing the inner cavity of the biological liquid nitrogen tank (1) is covered with a polymer hydrophobic coating.

8. A self-stabilizing biological liquid nitrogen device according to claim 1, characterized in that: The cold cycle device (3) comprises a refrigerator (33); The refrigerator (33) is a Stirling refrigerator, which performs heat exchange at different temperatures at the input end and the output end; wherein the metal pipeline (32) is respectively connected to the input end and the output end of the refrigerator (33).

9. A self-stabilizing biological liquid nitrogen device according to claim 8, characterized in that: The cold circulation device (3) also includes an expander (34) and a capillary tube (35).

10. A method for self-stabilizing a biological liquid nitrogen tank, comprising the self-stabilizing biological liquid nitrogen device according to any one of claims 1 to 9, characterized in that: Here are the steps: S101, supplying initial liquid nitrogen to the biological liquid nitrogen tank (1) through the conveying device (2), and confirming according to the display that the liquid nitrogen in the biological liquid nitrogen tank (1) reaches the initial temperature and liquid level requirements; S201, when the temperature sensor (12) detects that the temperature at the mouth of the biological liquid nitrogen tank (1) or in the cavity thereof has risen to a first threshold value, a signal for controlling the refrigeration circulation device (3) to start is sent to the control terminal (5); The cold circulation device (3) condenses the nitrogen in the biological liquid nitrogen tank (1), and cools the tank opening of the biological liquid nitrogen tank (1) by passing the condensed liquid nitrogen through a heat exchange device (111); S301, when the temperature sensor (12) detects that the temperature at the mouth of the biological liquid nitrogen tank (1) or in the cavity thereof drops below the first threshold, a signal is sent to the control terminal (5) to control the refrigeration circulation device (3) to be turned off; S401, when the liquid level sensor (13) detects that the liquid nitrogen level in the biological liquid nitrogen tank (1) drops to a second threshold value, a signal is sent to the control terminal (5) to control the start of the cold circulation device (3); The cold circulation device (3) condenses the nitrogen in the biological liquid nitrogen tank (1) and returns the liquid nitrogen to the tank through a metal pipeline (32); S501: When the liquid level sensor (13) detects that the liquid nitrogen level in the biological liquid nitrogen tank (1) rises above a second threshold value, a signal is sent to the control terminal (5) to control the refrigeration circulation device (3) to be turned off.

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