Liquid nitrogen self-exhausting biological sample bank drying and pressure maintaining device

Abstract

This invention discloses a liquid nitrogen self-venting biobank drying and pressure-maintaining device, comprising a liquid nitrogen refrigeration and storage device, a compressor refrigeration and storage device, and a drying device. The drying device is connected to multiple sets of liquid nitrogen refrigeration and storage devices and compressor refrigeration and storage devices. The drying device can receive drying gas from multiple sets of liquid nitrogen refrigeration and storage devices, and the drying gas in the drying device can dehumidify and dry the multiple sets of compressor refrigeration and storage devices. The beneficial effects of this invention are: the dried liquid nitrogen gas volatilized in multiple sets of liquid nitrogen refrigeration and storage devices is used to dehumidify and dry the sample chambers or sample transport chambers in multiple sets of compressor refrigeration and storage devices through the self-venting drying component. This device uses liquid nitrogen self-venting as the main gas source, without the need for additional continuous gas supply; and when the gas source of the self-venting drying component is insufficient or malfunctions, a backup drying gas component is activated to dry and dehumidify the compressor refrigeration and storage devices.

Description

Technical Field

[0001] This invention relates to the field of biobank technology, and in particular to a liquid nitrogen self-venting biobank drying and pressure-maintaining device. Background Technology

[0002] Traditional biobank liquid nitrogen storage equipment and ultra-low temperature freezers are susceptible to external humid air entering the equipment and sample storage chamber during operation, leading to increased humidity in the sample storage environment, which affects sample stability and equipment lifespan. Conventional dehumidification methods require an additional independent air source, which is energy-intensive, has an intermittent air supply, and has inconsistent interfaces between different brands and models of equipment, making modification and expansion difficult.

[0003] To address this, the inventors designed a liquid nitrogen self-venting biobank drying and pressure-maintaining device. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a liquid nitrogen self-venting biobank drying and pressure-maintaining device. This solves the problems of existing biobank compressor refrigeration storage equipment where moisture is mixed in during daily sample storage and retrieval, leading to internal frost formation, and the high energy consumption of traditional independent gas supply dehumidification solutions, as well as the waste of resources caused by the ineffective utilization of the natural evaporation of waste gas from liquid nitrogen storage equipment.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: The first aspect of the present invention provides a liquid nitrogen self-venting biobank drying and pressure-maintaining device, including a liquid nitrogen refrigeration storage device, a compressor refrigeration storage device, and a drying device; the drying device is connected to multiple sets of liquid nitrogen refrigeration storage devices and compressor refrigeration storage devices, the drying device can receive drying gas from multiple sets of liquid nitrogen refrigeration storage devices, and the drying gas in the drying device can dehumidify and dry multiple sets of compressor refrigeration storage devices.

[0006] As a preferred embodiment of the liquid nitrogen self-venting biobank drying and pressure-maintaining device of the present invention, the drying device includes a self-venting drying component; the drying gas in multiple sets of liquid nitrogen refrigeration and storage devices dehumidifies the humid gas in multiple sets of compressor refrigeration and storage devices through the self-venting drying component.

[0007] As a preferred embodiment of the liquid nitrogen self-venting biobank drying and pressure-maintaining device of the present invention, the self-venting drying component includes a receiving component, a filtering component, and a conveying component; the receiving component is connected to the conveying component through the filtering component, the receiving component is connected to multiple sets of liquid nitrogen refrigeration and storage devices, and the conveying component is connected to multiple sets of compressor refrigeration and storage devices.

[0008] As a preferred embodiment of the liquid nitrogen self-venting biobank drying and pressure-maintaining device of the present invention, the receiving component includes a receiving branch pipe, a first one-way valve, and a receiving main pipe; the receiving main pipe is connected to multiple sets of receiving branch pipes, each receiving branch pipe is equipped with a first one-way valve, and the multiple sets of receiving branch pipes are connected to multiple sets of liquid nitrogen refrigeration and storage equipment.

[0009] As a preferred embodiment of the liquid nitrogen self-venting biobank drying and pressure-maintaining device of the present invention, the conveying component includes a conveying pipe and an exhaust pipe; the conveying pipe is connected to a filtering component and multiple sets of compressor refrigeration and storage devices respectively; the drying gas conveyed by the conveying pipe dries the multiple sets of compressor refrigeration and storage devices, the exhaust pipe is connected to the multiple sets of compressor refrigeration and storage devices, and the multiple sets of compressor refrigeration and storage devices discharge humid gas through the exhaust pipe.

[0010] As a preferred embodiment of the liquid nitrogen self-venting biobank drying and pressure-maintaining device of the present invention, the conveying pipe includes a main conveying pipe, conveying branch pipes and a second valve; the main conveying pipe is connected to multiple sets of conveying branch pipes, the conveying branch pipes are equipped with a second valve, and the multiple sets of conveying branch pipes are connected to the compressor refrigeration and storage equipment.

[0011] As a preferred embodiment of the liquid nitrogen self-venting biological sample bank drying and pressure-maintaining device of the present invention, the exhaust pipe includes an exhaust main pipe, exhaust branch pipes and a third valve; the exhaust main pipe is connected to multiple sets of exhaust branch pipes, the exhaust branch pipes are provided with a third valve, and the multiple sets of exhaust branch pipes are connected to a compressor refrigeration and storage device.

[0012] As a preferred embodiment of the liquid nitrogen self-venting biobank drying and pressure-maintaining device of the present invention, the liquid nitrogen refrigeration and storage device is further provided with a micro positive pressure control module and a humidity module. The humidity module can detect the humidity of the liquid nitrogen refrigeration and storage device, and the positive pressure control module can control the drying gas in the liquid nitrogen refrigeration and storage device to dehumidify the compressor refrigeration and storage device through the self-venting drying component.

[0013] As a preferred embodiment of the liquid nitrogen self-venting biobank drying and pressure-maintaining device of the present invention, the filtering component includes a filter that can filter foreign matter in the drying gas inside the receiving component.

[0014] As a preferred embodiment of the liquid nitrogen self-venting biobank drying and pressure-maintaining device of the present invention, the drying device further includes a backup drying gas component, which can dehumidify and dry the compressor refrigeration storage equipment.

[0015] A second aspect of the present invention provides a method for drying and maintaining pressure in a liquid nitrogen self-venting biobank, using the aforementioned liquid nitrogen self-venting biobank drying and pressure maintaining device, comprising the following steps: The micro-positive pressure control module reads feedback values ​​from humidity sensors and micro-differential pressure sensors in multiple sets of liquid nitrogen refrigeration and storage devices and compressor refrigeration and storage devices according to a set cycle; The average micro-pressure difference, minimum micro-pressure difference, and maximum relative humidity characteristics of multiple sets of compressor refrigeration and storage equipment are extracted, and the operating status of the pipeline is determined by combining the micro-pressure difference feedback value of the liquid nitrogen refrigeration and storage equipment. Based on the determined pipeline operating status, calculate the gas source compensation intervention amount of the standby drying gas assembly and generate the corresponding adjustment command signal; The adjustment command signal is sent to the solenoid valve of the standby dry gas assembly to control its conduction state and adjust the gas flow rate discharged into the common header. Establish a fluid pressure difference within the common header; The first check valve opens when the pressure on the liquid nitrogen refrigeration and storage equipment side is higher than the pressure on the common header side. When the standby drying gas assembly supplies gas to the common header, causing the pressure on the common header side to be high, the first one-way valve closes under the action of reverse pressure difference. The internal high-pressure drying gas drives the second valve to conduct to the compressor refrigeration and storage equipment, and drives the third valve to discharge the humid gas.

[0016] Furthermore, the specific steps for extracting feature quantities, determining the operational status, and calculating compensation intervention quantities are as follows: From the feedback values ​​of each node of the compressor refrigeration and storage equipment, the maximum relative humidity is extracted as the highest relative humidity characteristic quantity, the minimum micro pressure difference is extracted as the global minimum micro pressure difference, and the average value of the micro pressure difference is calculated as the global average micro pressure difference. If the highest relative humidity characteristic is greater than or equal to the preset high humidity alarm upper limit, it is determined to be a high humidity abnormal state. The gas source compensation intervention amount is set to the maximum design flux, a digital full-load start command signal is generated and the steady-state algorithm is overridden until the highest relative humidity characteristic is continuously lower than the high humidity reset threshold. If the highest relative humidity characteristic value is less than the high humidity alarm upper limit, and the global minimum micro pressure difference is less than or equal to the safe pressure holding lower limit, or the global average micro pressure difference is less than the air pressure intervention trigger value, combined with the condition that the micro pressure difference on the liquid nitrogen side is lower than the preset gas source usable threshold, it is determined to be a gas source attenuation state, and the prediction compensation calculation is triggered: retrieve the global average micro pressure difference at the current moment and calculate the difference with the historical value at the previous sampling moment, divide it by the time interval to obtain the pressure difference attenuation slope; The target pressure setting is multiplied by the single pressure deviation of the current global average micro pressure difference by the proportional gain coefficient, combined with the cumulative sum of historical pressure deviations in the sampling period by the integral gain coefficient, and the pressure difference attenuation slope is multiplied by the differential gain coefficient. The above three items are logically summed to calculate the dynamic gas source compensation intervention amount. If the highest relative humidity characteristic value is less than the high humidity alarm upper limit, and the global minimum micro pressure difference is greater than the safe pressure holding lower limit, and the global average micro pressure difference is greater than or equal to the air pressure intervention trigger value, it is determined to be in the normal pressure holding state. The air source compensation intervention amount is set to zero, and a zero opening adjustment command signal is generated to put the device in the passive pressure holding natural operation state.

[0017] Furthermore, the physical evolution steps involved in establishing a fluid pressure difference, driving valves, and venting within the common header include: During the process of establishing a fluid pressure difference in the common header, based on the gas state equation, the fluid static pressure value inside the common header is composed of the initial pipeline filling pressure plus the cumulative definite integral of the difference between the gas mass inflow rate and outflow rate over the corresponding time period. This cumulative definite integral is directly proportional to the absolute temperature of the gas and inversely proportional to the effective volume. The high-pressure gas is transmitted to the front end of the second or third valve, and a pressure difference is formed between the internal fluid static pressure and the external environmental back pressure. This pressure difference is multiplied by the effective force-bearing cross-sectional area to obtain the physical driving force. When this physical driving force is greater than the sum of the preload of the mechanical return spring inside the valve and the frictional resistance of the mechanical seal, the valve is driven to disengage from the sealing seat. When the high-pressure dry gas enters the compressor refrigeration and storage equipment through the second valve, it uses the fluid pressure difference to mechanically squeeze and purge the humid and cold air mixed in with the pipeline network, and pushes the humid gas along the exhaust branch pipe and the third valve into the external environment within the set fluid replacement response cycle.

[0018] Furthermore, the specific method by which the micro-positive pressure control module acquires signals and outputs commands is as follows: The clock trigger unit inside the micro positive pressure control module synchronously sends power signals to each group of devices according to a set time period. After receiving the power signal, the sensors inside the devices return the environmental physical parameters at the current sampling time, which are then mapped to the underlying variable parameter set of the control model after analog-to-digital conversion. When the micro-positive pressure control module receives the zero-opening adjustment command signal, it cuts off the power supply to the solenoid valve's excitation coil to keep it off. When an analog opening adjustment command signal is received, a pulse width modulation signal with a continuously adjustable duty cycle is output to adjust the opening and closing duty cycle of the solenoid valve per unit time. When a digital full-load opening command signal is received, a continuous high-level drive signal is output to enable the solenoid valve to open the physical air passage in full-bore state.

[0019] This invention provides a liquid nitrogen self-venting biobank drying and pressure-maintaining device. It has the following beneficial effects: 1. This invention constructs a modular drying device and pipeline topology to collect and transport the naturally volatilized dry nitrogen generated in multiple sets of liquid nitrogen refrigeration and storage devices to multiple sets of compressor refrigeration and storage devices, thereby realizing the cascade utilization of gas sources and waste gas utilization among heterogeneous devices. Liquid nitrogen self-exhaust is used as the main gas source for the replacement dehumidification and micro-positive pressure maintenance of the sample chamber. Under normal conditions, no additional independent continuous gas supply and power equipment are required, thereby reducing the overall energy consumption and operating cost of the biobank.

[0020] 2. This invention uses a micro-positive pressure control module combined with a humidity module and a micro-differential pressure sensor to extract multi-modal features of pipeline physical parameters through real-time feedback. When the system determines that the gas source is insufficient or the humidity is abnormally high, the control algorithm dynamically adjusts and automatically switches to backup dry gas based on the differential pressure attenuation slope, achieving uninterrupted dehumidification and ensuring system stability. At the same time, by utilizing the automatic locking characteristic of the first one-way valve under reverse differential pressure, it effectively prevents high-pressure gas backflow caused by the backup gas source intervention, ensuring the safe operation of the liquid nitrogen refrigeration equipment under multi-gas source switching conditions.

[0021] 3. This invention establishes a passive response mechanism based on hydrostatic pressure evolution and mechanical valve core force balance. When the accumulated dry gas generates physical driving pressure, it can overcome mechanical resistance and automatically open the end valve group. The high-pressure dry gas generates mechanical compression and fluid purging effect on the invading humid airflow. After moisture intrusion occurs during routine sample storage, it can quickly rely on physical pressure difference to discharge moisture and rebuild a micro-positive pressure gas phase environment, effectively isolating external humid air, preventing frost formation inside the equipment, and improving sample storage safety.

[0022] 4. The pipes and drying components of this invention adopt a standardized quick-connect interface design, which is highly modular and compatible with various types of refrigeration and storage equipment, making the subsequent system modification and expansion extremely convenient. Attached Figure Description

[0023] Figure 1 This is a three-dimensional schematic diagram of a liquid nitrogen self-venting biobank drying and pressure-maintaining device.

[0024] Figure 2 This is another schematic diagram of a liquid nitrogen self-venting biobank drying and pressure-maintaining device.

[0025] Figure 3 A top view of a liquid nitrogen self-venting biobank drying and pressure-maintaining device; Figure 4 This is a schematic diagram of the system architecture of the present invention; Figure 5 This is a schematic diagram of the method flow of the present invention; Figure 6 This is a schematic diagram illustrating the multimodal boundary delineation of data acquisition and operational status in this invention. Figure 7This is a schematic diagram of the gas source compensation intervention decision based on multimodal operating conditions according to the present invention; Figure 8 This is a schematic diagram of the hardware drive control and gas path physical response of the present invention; Figure 9 This is a schematic diagram of the pipeline fluid dynamics evolution and directional dehumidification logic of the present invention; Figure 10 This is a schematic diagram comparing the system dynamic timing response and dehumidification effect of the present invention.

[0026] The components include: 1. Liquid nitrogen refrigeration and storage equipment; 2. Compressor refrigeration and storage equipment; 3. Drying device; 31. Self-exhausting drying assembly; 311. Receiving component; 312. Filtering component; 313. Conveying component; 3111. Receiving branch pipe; 3112. First one-way valve; 3113. Receiving main pipe; 3131. Conveying fitting; 3132. Exhaust fitting; 31311. Conveying main pipe; 31312. Conveying branch pipe; 31313. Second valve; 31321. Exhaust main pipe; 31322. Exhaust branch pipe; 31323. Third valve; 3121. Filter; 32. Backup drying gas assembly. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] See attached document Figure 1 -Appendix Figure 3 A liquid nitrogen self-venting biobank drying and pressure-maintaining device is provided, which includes a liquid nitrogen refrigeration storage device 1, a compressor refrigeration storage device 2, and a drying device 3; the drying gas discharged from the liquid nitrogen refrigeration storage device 1 dehumidifies and dries the compressor refrigeration storage device 2 through the drying device 3.

[0029] Specifically, it includes a liquid nitrogen refrigeration and storage device 1, a compressor refrigeration and storage device 2, and a drying device 3; the drying device 3 is connected to multiple sets of liquid nitrogen refrigeration and storage devices 1 and compressor refrigeration and storage devices 2, the drying device 3 can receive drying gas from multiple sets of liquid nitrogen refrigeration and storage devices 1, and the drying gas in the drying device 3 can dehumidify and dry multiple sets of compressor refrigeration and storage devices 2.

[0030] Furthermore, the drying device 3 includes a self-exhausting drying component 31; the drying gas in the multiple sets of liquid nitrogen refrigeration storage devices 1 dehumidifies the humid gas in the multiple sets of compressor refrigeration storage devices 2 through the self-exhausting drying component 31.

[0031] The self-exhausting drying assembly 31 can receive the dry liquid nitrogen gas volatilized in multiple sets of liquid nitrogen refrigeration and storage devices 1, and can also transport this dry nitrogen gas to the sample chamber or sample transfer chamber in multiple sets of compressor refrigeration and storage devices 2 to achieve dehumidification and drying of the chamber.

[0032] Furthermore, the self-exhaust drying assembly 31 includes a receiving component 311, a filtering component 312, and a conveying component 313; the receiving component 311 is connected to the conveying component 313 through the filtering component 312, the receiving component 311 is connected to multiple sets of liquid nitrogen refrigeration and storage devices 1, and the conveying component 313 is connected to multiple sets of compressor refrigeration and storage devices 2.

[0033] Preferably, the receiving component 311 can receive the dry gas from several sets of liquid nitrogen refrigeration storage devices 1, and the receiving component 311 conveys the gas to the sample chamber or sample storage and transfer chamber of several sets of compressor refrigeration storage devices 2 through the filtering component 312 and the conveying component 313, so as to achieve dehumidification and drying inside the chamber.

[0034] Furthermore, the receiving component 311 includes a receiving branch pipe 3111, a first one-way valve 3112, and a receiving main pipe 3113; the receiving main pipe 3113 is connected to multiple sets of receiving branch pipes 3111, the receiving branch pipes 3111 are equipped with the first one-way valve 3112, and the multiple sets of receiving branch pipes 3111 are connected to multiple sets of liquid nitrogen refrigeration and storage devices 1.

[0035] Preferably, by setting the receiving branch pipes 3111 into several groups, each group of receiving branch pipes 3111 can be connected to a group of liquid nitrogen refrigeration storage devices 1, so as to collect the dry gas in the several groups of liquid nitrogen refrigeration storage devices 1 and filter it through the filter component 312.

[0036] Furthermore, the conveying component 313 includes a conveying pipe 3131 and an exhaust pipe 3132; the conveying pipe 3131 is connected to the filter component 312 and the multiple sets of compressor refrigeration and storage devices 2 respectively; the dry gas conveyed by the conveying pipe 3131 dries the multiple sets of compressor refrigeration and storage devices 2, and the exhaust pipe 3132 is connected to the multiple sets of compressor refrigeration and storage devices 2, and the multiple sets of compressor refrigeration and storage devices 2 discharge humid gas through the exhaust pipe 3132.

[0037] Preferably, several sets of compressor refrigeration and storage equipment 2 can be dehumidified and dried through the conveying pipe 3131, and the humid gas can be discharged through the exhaust pipe 3132.

[0038] Furthermore, the conveying pipe fitting 3131 includes a main conveying pipe 31311, a branch conveying pipe 31312, and a second valve 31313; the main conveying pipe 31311 is connected to multiple sets of branch conveying pipes 31312, and the branch conveying pipes 31312 are equipped with second valves 31313; the multiple sets of branch conveying pipes 31312 are connected to the compressor refrigeration storage equipment 2.

[0039] Furthermore, the exhaust pipe 3132 includes an exhaust main pipe 31321, an exhaust branch pipe 31322, and a third valve 31323; the exhaust main pipe 31321 is connected to multiple sets of exhaust branch pipes 31322, the exhaust branch pipes 31322 are provided with a third valve 31323, and the multiple sets of exhaust branch pipes 31322 are connected to the compressor refrigeration storage device 2.

[0040] Preferably, the receiving component 311, the filtering component 312, and the conveying component 313 are designed as modular components for easy assembly, with standardized quick-connect interfaces, compatible with various types of equipment, and convenient for modification and expansion.

[0041] Furthermore, the liquid nitrogen refrigeration storage device 1 is also equipped with a micro positive pressure control module and a humidity module. The humidity module can detect the humidity of the liquid nitrogen refrigeration storage device 1, and the positive pressure control module can control the dry gas in the liquid nitrogen refrigeration storage device 1 to dehumidify the compressor refrigeration storage device 2 through the self-exhausting drying component 31.

[0042] It should be noted that the humidity module and the micro-positive pressure control module can maintain the dryness of the liquid nitrogen refrigeration storage device 1 by applying a micro-positive pressure, and control the opening or closing of the first one-way valve 3112.

[0043] Furthermore, the filtering component 312 includes a filter 3121, which can filter foreign objects in the dry gas within the receiving component 311.

[0044] Furthermore, the drying device 3 also includes a backup drying gas assembly 32, which can dehumidify and dry the gas in the compressor refrigeration storage device 2.

[0045] It should be noted that when the dry gas inside the liquid nitrogen refrigeration storage device 1 is insufficient or when the liquid nitrogen refrigeration storage device 1 malfunctions, the backup dry gas assembly 32 can be used to continuously dehumidify and dry several sets of compressor refrigeration storage devices 2.

[0046] In summary, this invention utilizes the evaporated dry liquid nitrogen gas within multiple sets of liquid nitrogen refrigeration storage devices 1, and dehumidifies and dries the sample chambers or sample transport chambers within multiple sets of compressor refrigeration storage devices 2 via a self-exhausting drying assembly 31. This device uses liquid nitrogen self-exhaust as the primary gas source, eliminating the need for additional continuous gas supply, thus reducing energy consumption and operating costs. Furthermore, when the gas source of the self-exhausting drying assembly 31 is insufficient or malfunctions, a backup drying gas assembly 32 is activated to dry and dehumidify the compressor refrigeration storage devices 2. This achieves automatic switching between multiple gas sources, uninterrupted dehumidification, and strong system stability. A micro-positive pressure control module continuously maintains dryness, effectively isolating external humid air and improving sample storage safety. The device uses a standardized quick-connect interface, making it compatible with various types of equipment and facilitating modification and expansion.

[0047] To achieve pressure balance monitoring, dynamic airflow switching, and closed-loop control of the micro-positive pressure state under the aforementioned multi-gas source architecture, this embodiment further incorporates the attached... Figure 1 To be continued Figure 4 The underlying pipeline topology and sensor hardware layer of the liquid nitrogen self-venting biobank drying and pressure-maintaining device are described in detail: Humidity sensors and micro-differential pressure sensors are installed in the gas phase space, exhaust port, sampling branch, or detection chamber connected to the inside of each liquid nitrogen refrigeration and storage device 1. Humidity sensors and micro-differential pressure sensors are installed in the sample chamber, sample transfer chamber, exhaust port, sampling branch, or detection cavity connected to the inside of the compressor refrigeration and storage device 2 of each set of compressor refrigeration and storage device 2. The drying device 3 is equipped with a common main pipe, which is the gas supply main pipe downstream of the filter component 312 and connected to the main delivery pipe 31311. The dry nitrogen generated by the natural evaporation of the liquid nitrogen refrigeration storage device 1 enters the common main pipe after passing through the receiving branch pipe 3111, the first one-way valve 3112, the receiving main pipe 3113 and the filter component 312. The standby dry gas assembly 32 is connected to the common main pipe through a solenoid valve. The inlet of multiple sets of receiving branch pipes 3111 is connected to multiple sets of liquid nitrogen refrigeration and storage equipment 1, and the outlet is connected to a common main pipe. The first one-way valve 3112 is installed on the receiving branch pipe 3111 and has a mechanical structure that allows one-way flow from the liquid nitrogen refrigeration storage device 1 toward the receiving main pipe 3113 or the common header pipe. When the pressure on the common header side is higher than the pressure on the liquid nitrogen refrigeration and storage device 1 side, the first one-way valve 3112 is locked under the physical action of the reverse pressure difference and blocks the physical path of the backup dry gas to the liquid nitrogen refrigeration and storage device 1. The inlet end of the multiple sets of conveying branch pipes 31312 is connected to the common main pipe and the outlet end is connected to the multiple sets of compressor refrigeration and storage equipment 2 respectively; The second valve 31313 is installed on the conveying branch pipe 31312. The second valve 31313 is a micro-differential opening valve, a one-way valve or a pressure-controlled conducting valve, and it conducts towards the compressor refrigeration storage device 2 when a predetermined micro-positive pressure is formed in the common header. The inlet ends of multiple sets of exhaust branch pipes 31322 are respectively connected to multiple sets of compressor refrigeration and storage equipment 2; The third valve 31323 is installed on the exhaust branch pipe 31322. The third valve 31323 is an exhaust check valve, a pressure relief valve or a micro-pressure differential opening valve, and when the internal pressure of the compressor refrigeration storage device 2 reaches the preset exhaust pressure differential, it is directed to the exhaust main pipe 31321 or the external environment to discharge humid gas. The standby dry gas assembly 32 is connected to the common main pipe via a pipeline. The standby dry gas assembly 32 includes at least one of a standby nitrogen cylinder, a nitrogen generator, or other dry inert gas source and is equipped with a pressure reducing valve, a pressure regulating valve, a flow limiting valve, or a safety pressure relief device to keep the pressure and flow rate of the dry gas entering the common main pipe within a preset safe range. The solenoid valve is installed on the connecting pipeline between the standby dry gas assembly 32 and the common header; The input terminal of the micro positive pressure control module is electrically connected to the humidity sensor and micro differential pressure sensor in each group of liquid nitrogen refrigeration storage equipment 1, the input terminal of the micro positive pressure control module is electrically connected to the humidity sensor and micro differential pressure sensor in each group of compressor refrigeration storage equipment 2, and the output terminal of the micro positive pressure control module is electrically connected to the solenoid valve. The micro differential pressure sensor outputs the pressure difference signal corresponding to the internal pressure of the device, the sampling branch or the detection chamber relative to the external environment, the exhaust end or the common header.

[0048] See attached document Figure 5 The present invention provides a method for drying and maintaining pressure in a liquid nitrogen self-venting biobank, comprising the following steps: S1, the micro positive pressure control module reads the feedback values ​​of the humidity sensor and micro differential pressure sensor inside the liquid nitrogen refrigeration storage device 1 according to the set time cycle, and at the same time reads the feedback values ​​of the humidity sensor and micro differential pressure sensor inside the compressor refrigeration storage device 2. S2, the micro positive pressure control module performs mathematical calculations on the collected feedback values, extracts the average micro pressure difference, minimum micro pressure difference and maximum relative humidity characteristic values ​​of multiple sets of compressor refrigeration storage devices 2, and combines the micro pressure difference feedback values ​​of multiple sets of liquid nitrogen refrigeration storage devices 1 to extract the physical state indicators of the liquid nitrogen natural exhaust gas source and thus identify the operating status of the pipeline. S3, the micro positive pressure control module calculates the gas source compensation intervention amount of the standby dry gas component 32 based on the determined pipeline operation status and generates the corresponding adjustment command signal. S4, the micro positive pressure control module sends the adjustment command signal to the solenoid valve, controls the conduction state of the solenoid valve, and adjusts the physical quantity of the airflow discharged from the standby dry gas assembly 32 into the common header. S5, the gas discharged into the common header changes the static pressure of the fluid inside the common header. The device establishes a fluid pressure difference outward based on the change in static pressure inside the common header. When the pressure on the liquid nitrogen refrigeration storage device 1 side is higher than the pressure of the common header, the first one-way valve 3112 is opened towards the common header. When the standby dry gas assembly 32 replenishes the common header and makes the pressure of the common header higher than the pressure on the side of the liquid nitrogen refrigeration storage device 1, the first one-way valve 3112 is locked under the action of reverse pressure difference. The dry gas in the common header drives the second valve 31313 to conduct towards the compressor refrigeration storage device 2 through the fluid pressure difference, and drives the third valve 31323 to discharge the humid gas that has been replaced in the compressor refrigeration storage device 2 to the outside, thus performing directional airflow transmission and dehumidification operation on the compressor refrigeration storage device 2.

[0049] See attached document Figure 6 Steps S1 and S2, in their specific implementation, include the following steps: S11, the clock trigger unit inside the micro positive pressure control module synchronously sends power signals to multiple sets of liquid nitrogen refrigeration and storage devices 1 and multiple sets of compressor refrigeration and storage devices 2 according to the set time period. After receiving the power signal, the humidity sensor and micro differential pressure sensor inside each device return the environmental physical parameters corresponding to the current sampling time. The analog-to-digital conversion and communication protocol of the humidity sensor and micro differential pressure sensor execute the underlying data transmission logic set by the fieldbus standard. S12, after receiving the aforementioned discrete physical parameters, the micro-positive pressure control module maps them to the variable space of the control model, and sets the number of liquid nitrogen refrigeration storage devices 1 managed by the micro-positive pressure control module to be... And the number of compressor refrigeration storage devices 2 is , and All are natural numbers greater than or equal to 1, at any consecutive sampling time The system constructs a set of underlying variable parameters and defines them. Indicates the first The liquid nitrogen refrigeration and storage device 1 provides real-time feedback of the micro-pressure difference value. Values ​​range from 1 to positive integers, and define Indicates the first The compressor refrigeration storage device 2 provides real-time feedback of the micro-pressure difference value and defines it. Indicates the first The relative humidity value is fed back in real time by the compressor refrigeration and storage device 2. Values ​​range from 1 to The positive integers indicate that the micro-positive pressure control module stores the real-time collected underlying variable parameters in its internal cache unit to complete the construction of the system status data for the current cycle.

[0050] S21, the micro-positive pressure control module retrieves the set of underlying variable parameters in the internal cache unit and performs mathematical model calculations of the spatial global feature parameters. Based on the physical topology characteristics of the parallel pipeline network, the pressure loss or moisture intrusion of local nodes changes the global aerodynamic balance. The minimum micro-pressure difference corresponds to the worst local sealing node in the system, the average micro-pressure difference corresponds to the global air supply abundance of the common main pipe, and the highest relative humidity corresponds to the extreme value of local moisture intrusion caused by equipment door opening operation. The micro-positive pressure control module obtains the aforementioned three core feature parameters through feature quantity extraction calculations and characterizes the boundary conditions of the overall pipeline network. The micro-positive pressure control module calculates the global minimum micro-pressure difference, global average micro-pressure difference, and maximum relative humidity characteristic for multiple sets of compressor refrigeration and storage devices 2, and calculates the average micro-pressure difference or minimum micro-pressure difference on the liquid nitrogen side for multiple sets of liquid nitrogen refrigeration and storage devices 1, and characterizes the availability status of the liquid nitrogen natural exhaust gas source; the formula for the micro-positive pressure control module to calculate the global minimum micro-pressure difference is: ; The formula for calculating the global average differential pressure is: ; The formula for calculating the characteristic value of the highest relative humidity is: ; In the formula, For a moment The global minimum differential pressure value; The function is for finding the minimum value; For a moment No. Measured micro-pressure difference values ​​at each pressure sensor node; For a moment The global average differential pressure value; This represents the total number of pressure sensor nodes distributed within the system. This is the discrete summation operator; This is an independent sequence number variable for the pressure sensor node; For a moment No. Measured micro-pressure difference values ​​at each pressure sensor node; This is the current sampling time; For a moment The global maximum humidity value; This is a function to find the maximum value. For a moment No. The measured relative humidity values ​​at each humidity sensor node.

[0051] S22, the micro-positive pressure control module uses the extracted spatial global feature parameters to perform numerical comparison with the preset system threshold matrix and executes the boundary division logic of the pipeline multi-modal operation status. The safety pressure holding lower limit value included in the system threshold matrix is ​​set according to the mechanical conduction pressure difference calibration of the second valve 31313. The air pressure intervention trigger value is set to be greater than the safety pressure holding lower limit value and the difference between the air pressure intervention trigger value and the safety pressure holding lower limit value corresponds to the redundancy buffer zone of the control algorithm. The high humidity alarm upper limit value is set according to the drying standard of the biological sample storage environment. The logic judgment unit inside the micro-positive pressure control module performs condition matching calculation on the aforementioned feature parameters and corresponding thresholds and outputs the corresponding operation status result. When executing the boundary division logic, the micro-positive pressure control module first determines whether the highest relative humidity characteristic is greater than or equal to the high humidity alarm upper limit. If the highest relative humidity characteristic is greater than or equal to the high humidity alarm upper limit, the micro-positive pressure control module executes the over-authority judgment logic, blocks the current differential pressure value judgment condition, and directly determines that the device has entered the high humidity abnormal state. If the highest relative humidity characteristic value is less than the high humidity alarm upper limit, the micro positive pressure control module determines the pressure difference condition; when the global minimum micro pressure difference is less than or equal to the safety pressure holding lower limit or the global average micro pressure difference is less than the air pressure intervention trigger value, the micro positive pressure control module combines the micro pressure difference feedback value on the liquid nitrogen refrigeration storage device 1 side to execute the judgment logic. When the micro-pressure difference on the liquid nitrogen side is lower than the preset gas source availability threshold or the pressure on both sides of the compressor refrigeration storage device is in a continuous decreasing state, the micro-positive pressure control module determines that the device is in a gas source attenuation state. If the highest relative humidity characteristic is less than the high humidity alarm upper limit and the global minimum micro-pressure difference is greater than the safe pressure holding lower limit, while the global average micro-pressure difference is greater than or equal to the gas pressure intervention trigger value, the micro-positive pressure control module determines that the current device is in a normal pressure holding state. The pipeline operation status result obtained by the determination is solidified as a decision variable in the memory stack of the current control cycle and passed to the subsequent instruction calculation stage. The micro-positive pressure control module has a high humidity reset threshold that is lower than the high humidity alarm upper limit. When the highest relative humidity characteristic is lower than the high humidity reset threshold and continues to reach the preset sampling cycle number, the micro-positive pressure control module determines that the high humidity abnormal state is resolved.

[0052] See attached document Figure 7 Step S3, in its specific implementation, includes the following steps: S31, the micro-positive pressure control module reads the pipeline operation status results stored in the memory stack of the current control cycle and performs matching branch operation. When the device is in the normal pressure holding state, the micro-positive pressure control module determines the flow rate of nitrogen generated by the natural evaporation of liquid nitrogen refrigeration storage device 1 according to the preset logical mapping relationship to maintain the micro-positive pressure boundary of the pipeline network. The algorithm unit inside the micro-positive pressure control module assigns the gas source compensation intervention amount of the standby dry gas component 32 to zero and generates a zero opening adjustment command signal accordingly. The zero opening adjustment command signal is transmitted to the end actuator through the hardware driver layer as the control output of the current cycle and the corresponding device is in the passive pressure holding natural operation state.

[0053] S32, when the device is in a gas source attenuation state, the micro-positive pressure control module triggers a predictive compensation calculation based on the differential pressure attenuation slope. The micro-positive pressure control module retrieves the global average micro-differential pressure values ​​from multiple consecutive historical sampling periods to calculate the differential pressure attenuation slope at the current moment. The calculation formula is as follows: ; In the formula, For a moment The second differential pressure attenuation slope parameter at the location; This is the current sampling time; For the current moment Real-time calculation of global average micro-pressure difference; This refers to a time point that is shifted forward by one sampling period from the current moment; This represents the historical value of the global average micro-pressure difference at the previous sampling time; In this embodiment, the time interval between adjacent sampling moments is determined based on the hardware clock of the control system. The value range is from 10ms to 100ms; The micro-positive pressure control module obtains the continuous decay rate of pipeline fluid pressure through differential calculation, reflecting the dynamic evolution trend of pressure loss within the pipeline network.

[0054] S33, after extracting the differential pressure attenuation slope, the micro-positive pressure control module executes a discrete proportional-integral-differential algorithm to solve for the dynamic gas source compensation intervention amount, and sets a target pressure holding setpoint that is greater than the gas pressure intervention trigger value and less than the upper limit of the safe pressure holding value allowed by the compressor refrigeration storage device 2 and the pipeline network. The formula for calculating the pressure deviation value by the micro-positive pressure control module is: ; In the formula, To set the time within the accumulation period Calculated values ​​of pressure deviation at the location; In this embodiment, the target holding pressure is set to a certain value. The value range is from 200 Pa to 800 Pa; For the current moment The global average differential pressure value; This is the current sampling time; The formula for calculating the gas source compensation intervention amount is: ; In the formula, For a moment The gas source compensation intervention volume adjustment command value; This is the current sampling time; In this embodiment, the proportional gain coefficient of the control system is... The value range is from 0.5 to 5.0; For the current moment The calculated value of the single pressure deviation; In this embodiment, the integral gain coefficient of the control system is... The value range is from 0.01 to 0.5; This is the discrete summation operator; The cumulative variable is the number of steps in the discrete sampling period; In this embodiment, to control the total number of cumulative sampling steps set in the control logic, The value range is from 10 to 100; For the first Calculated value of single pressure deviation for each sampling period; In this embodiment, the time interval between adjacent sampling moments is determined based on the hardware clock of the control system. The value range is from 10ms to 100ms; In this embodiment, the differential gain coefficient of the control system is... The value range is from 0.1 to 2.0; For a moment The second differential pressure attenuation slope parameter at the location; The micro-positive pressure control module establishes a proportional function by combining the rated drive voltage of the solenoid valve with the maximum design throughput of the standby dry gas assembly 32. Based on the proportional function, the micro-positive pressure control module maps the gas source compensation intervention amount to generate a corresponding analog quantity opening adjustment command signal.

[0055] S34, when the device is in a high humidity abnormal state, the micro positive pressure control module is interrupted and overrides the aforementioned steady-state adjustment algorithm. The micro positive pressure control module determines that the current system pipeline is encountering the intrusion of external humid and cold airflow and is in a non-steady-state condition of reconstructing the pressure barrier based on the physical boundary conditions of the high humidity abnormal state. The micro positive pressure control module sets the gas source compensation intervention amount of the backup dry gas component 32 to the maximum design throughput of the hardware system and generates a digital full-load start command signal accordingly. The digital full-load start command signal is used as the highest execution priority parameter in the logic judgment unit to override the steady-state numerical solution result and as the preferred control output of the current control cycle. When the highest relative humidity characteristic value is lower than the preset high humidity reset threshold for several consecutive sampling cycles and the global average micro pressure difference recovers to the target pressure holding range, the micro positive pressure control module exits the high humidity abnormal state and switches to the gas source attenuation state or the normal pressure holding state according to the current pressure state.

[0056] See attached document Figure 8 Step S4, in its specific implementation, includes the following steps: S41, the micro positive pressure control module converts the calculated adjustment command signal into a physical drive signal and sends it to the control port of the solenoid valve through an electrical hard wire. When the device transmits the zero opening adjustment command signal to the hardware layer, the micro positive pressure control module cuts off the power supply to the excitation coil of the solenoid valve. The solenoid valve remains in the cut-off state under the action of the internal reset spring, so that the physical quantity of the airflow discharged from the standby dry gas component 32 into the common header is maintained at zero flow. The external gas supply is interrupted and the pressure balance of the bottom layer of the pipeline is maintained by the natural exhaust of the liquid nitrogen refrigeration storage device 1. S42, when the hardware layer receives the analog opening adjustment command signal, the micro positive pressure control module outputs a pulse width modulation signal with continuously adjustable duty cycle to the drive circuit of the solenoid valve. By controlling the opening and closing duty cycle of the solenoid valve per unit time, the equivalent average gas flow rate of the standby dry gas assembly 32 into the common header is adjusted. The dry gas stored inside the standby dry gas assembly 32 is discharged into the common header according to the calculated gas source compensation intervention amount and a fluid distribution boundary is established in the pipeline network. The fluid medium discharged into the common header fills the deficiency of the natural exhaust volume of the liquid nitrogen refrigeration storage device 1 and constructs a corresponding dynamic pressure compensation area in the pipeline network. S43, when the device sends a digital full-load start command signal to the hardware layer, the micro positive pressure control module outputs a continuous high-level drive signal to the excitation coil of the solenoid valve. The valve core of the solenoid valve overcomes the internal mechanical resistance to reach the maximum mechanical stroke and conducts the physical gas path from the backup dry gas assembly 32 to the common header in the full-bore state. The dry gas stored inside the backup dry gas assembly 32 is discharged into the common header in this state at the maximum flow rate and maximum calibration pressure set by the hardware. The influx of large flow gas changes the hydrostatic pressure balance inside the common header within the set response period and establishes a directional expansion fluid high-pressure boundary condition within the entire pipeline system. During the period when the backup dry gas assembly 32 intervenes to replenish gas, the pressure of the common header increases and is higher than the pressure on the side of the liquid nitrogen refrigeration storage device 1. The first one-way valve 3112 remains closed under the action of reverse pressure difference and prevents the gas in the common header from flowing back into the liquid nitrogen refrigeration storage device 1. When the pressure of naturally volatilized nitrogen on the side of the liquid nitrogen refrigeration storage device 1 is higher than the pressure of the common header again and reaches the opening pressure difference of the first one-way valve 3112, the first one-way valve 3112 resumes the one-way conduction state towards the common header.

[0057] See attached document Figure 9 Step S5, in its specific implementation, includes the following steps: S51, the solenoid valve releases dry gas according to the full-load opening command transmitted from the hardware layer, and allows the dry gas to enter the common header. The fluid medium entering the common header undergoes a process of fluid kinetic energy conversion to fluid static pressure under the combined effect of the sudden change in pipe cross-sectional area and the pipe wall obstruction effect. The evolution mechanism of the pipeline static pressure variable is set according to the gas state equation as follows: ; In the formula, For public mother management at all times The internal hydrostatic pressure value at the location; This is the current time when integration ends; Fill in the initial pressure values ​​for the pipeline network before fluid introduction; From the initial moment Up to the current moment The definite integral operator; This is the universal gas constant; The absolute temperature of the gas inside the pipe; The effective internal volume of the common header is determined based on its structural dimensions. For a moment Gas mass inflow rate determined based on the mechanical diameter of the solenoid valve; For a moment The gas mass outflow rate resulting from natural leakage through the system's micropores; It serves as a time auxiliary variable in the definite integral operation process; Integral infinitesimal element with time as an auxiliary variable; The high-flow-rate continuous airflow provided by the standby dry gas assembly 32 makes the mass inflow rate higher than the mass outflow rate and drives the hydrostatic pressure inside the common header to rise continuously. S52, the continuously accumulated fluid static pressure inside the common header forms a local high-pressure potential energy zone in the bottom layer of the pipeline network. The local high-pressure potential energy zone is physically transmitted along the inner wall of the common header to each end branch of the device pipeline in the form of pressure waves. As the mechanical diameter of the solenoid valve 321 continues to conduct, the fluid static pressure value in the common header gradually approaches and reaches the opening critical pressure threshold of the passive mechanical valve group of each branch of the pipeline network. The opening critical pressure threshold is set by the spring stiffness coefficient inside the passive mechanical valve group in combination with the initial compression preload. The high-pressure fluid medium flows along the distribution direction of the pressure drop gradient to the relatively low-pressure far end pipeline and fills the physical path of the gas source distribution. The gas conduction process converts the local gas source compensation intervention into the physical state of the whole system fluid dynamic response and accumulates fluid static pressure driving force at the end face of each passive mechanical valve group.

[0058] S53, when the high-pressure gas flowing along the pipeline reaches each terminal branch, the hydrostatic pressure carried by the high-pressure gas directly acts on the valve core end face of the passive mechanical valve group in the closed state. The physical driving force is calculated according to the principle of force balance using the following formula: ; In the formula, The physical driving force applied by the gas to the valve core; The internal fluid static pressure before the high-pressure gas is transmitted to the designated mechanical valve; The ambient back pressure applied after the specified mechanical valve by the external atmospheric environment; This refers to the effective force-bearing cross-sectional area of ​​the valve core facing the fluid in a corresponding mechanical valve. When the high-pressure gas is conducted to the main delivery pipe 31311 and the exhaust side of the compressor refrigeration storage device 2, the pressure difference between the common main pipe and the compressor refrigeration storage device 2 acts on the mechanical seal of the second valve 31313 and causes the second valve 31313 to open towards the compressor refrigeration storage device 2. The exhaust pressure difference formed after the compressor refrigeration storage device 2 is replaced by dry gas acts on the mechanical seal of the third valve 31323 and causes the third valve 31323 to open towards the exhaust main pipe 31321 or the external environment. The first one-way valve 3112 is unidirectionally open or reversely closed according to the pressure difference between the liquid nitrogen refrigeration storage device 1 side and the common main pipe side and prevents the gas in the common main pipe from flowing back to the liquid nitrogen refrigeration storage device 1.

[0059] S54, when the physical driving force of the gas acting on the valve core is greater than the sum of the preload of the internal mechanical return spring and the frictional resistance of the mechanical seal, the valve cores of the second valve 31313 and the third valve 31323 disengage from the sealing valve seat under the action of the front-end fluid pressure. Each branch valve group undergoes mechanical displacement under the drive of the fluid pressure difference and opens the air intake and exhaust channels of the corresponding physical area of ​​the pipeline network. The first one-way valve 3112 does not serve as the exhaust channel when the common header is replenished with gas and performs one-way conduction or reverse blocking according to the pressure difference between the liquid nitrogen refrigeration storage equipment 1 side and the common header side. The high-pressure dry gas in the common header passes through the main conveying pipe 31311 and the branch conveying pipe 31312. The second valve 31313 enters the compressor refrigeration storage device 2 and pushes the humid gas in the compressor refrigeration storage device 2 to be discharged to the external environment through the exhaust branch pipe 31322, the third valve 31323 and the exhaust main pipe 31321. When the high-pressure dry gas flows through the branch pipe network, it exerts mechanical compression and fluid purging effect on the humid and cold airflow mixed in the branch pipe network. The high humidity gas trapped in the pipe network is discharged into the external environment along the exhaust channel under the direct push of the high-pressure dry airflow at the front end. The device discharges the internal moisture within the fluid replacement response period calculated based on the total volume of the pipe network and the calibrated exhaust flow rate and establishes a micro-positive pressure gas phase environment composed of pure dry gas in the pipe network.

[0060] To aid in understanding the technical solution of this invention, the following provides an application example of a liquid nitrogen self-venting biobank drying and pressure-maintaining device.

[0061] The system target pressure setting is 400Pa, the safety pressure lower limit is 80Pa, the air pressure intervention trigger value is 200Pa, the high humidity alarm upper limit is 45% relative humidity, and the high humidity reset threshold is 35% relative humidity.

[0062] At the sampling time corresponding to the normal pressure holding state, the micro-positive pressure control module extracted the highest relative humidity characteristic of the 6 compressor refrigeration storage devices as 18.5%. The highest relative humidity characteristic is less than the upper limit of the high humidity alarm. The micro-positive pressure control module calculated that the global minimum micro-pressure difference is 285.3 Pa, which is greater than the lower limit of the safe pressure holding. The global average micro-pressure difference is 312.4 Pa, which is greater than the gas pressure intervention trigger value. The internal algorithm unit of the micro-positive pressure control module sets the gas source compensation intervention amount to zero and outputs a zero opening adjustment command signal. The solenoid valve remains de-energized and the backup dry gas source does not intervene in the common main pipe.

[0063] After several consecutive cycles of gas source attenuation, the system calculates that the global average micro-pressure difference drops to 165.8 Pa, which is lower than the gas pressure intervention trigger value. The highest relative humidity characteristic is 21.2%. The micro-positive pressure control module retrieves historical data and calculates that the current pipeline pressure is decreasing at a rate of 6.5 Pa per second. The micro-positive pressure control module calculates the pressure deviation between the target pressure setting and the current average value. The micro-positive pressure control module combines the attenuation slope to perform proportional-integral-differential operations and maps the calculated dynamic gas source compensation intervention amount into an analog quantity opening adjustment command signal with a duty cycle of 38%. The solenoid valve is in a dynamic conducting state, allowing the standby dry nitrogen to flow into the common header and raising the global average micro-pressure difference to between 390 Pa and 410 Pa.

[0064] When the doors of the two compressor refrigeration and storage devices are opened, the highest relative humidity characteristic reaches 72.4%, which is greater than the high humidity alarm limit. The micro positive pressure control module executes the over-authorization judgment logic and determines that the device has entered the high humidity abnormal state. The micro positive pressure control module sends a digital full-load opening command signal to the hardware layer. The solenoid valve excitation coil receives a high level, causing the valve core to reach its maximum stroke and conduct through the entire diameter. The backup gas source enters the common header. The static pressure of the fluid in the common header rises to 850Pa within 5 seconds. The pressure on the side of the common header is higher than the pressure on the side of the liquid nitrogen refrigeration and storage device, causing the first one-way valve to close under the reverse pressure difference. The physical driving force generated by the 850Pa high-pressure airflow along the pipeline is greater than the preload force of the reset spring, causing the second valve of the corresponding device to open. The high-pressure dry gas enters the compressor refrigeration and storage device, squeezing the humid gas and discharging it into the external environment through the third valve until the relative humidity is below 35% for 10 consecutive cycles.

[0065] This experiment selected 12 cryogenic compressor refrigeration and storage devices of the same model and divided them into two groups, which were connected to independent test pipelines. The experimental group was equipped with a micro positive pressure control module and connected to the liquid nitrogen receiving main pipeline, common header, solenoid valve and mechanical valve group. The control group was equipped with a constant flow nitrogen direct supply pipeline.

[0066] In the initial experimental environment, the internal temperature of both groups of equipment was pre-cooled to -80 degrees Celsius, and the maximum relative humidity of the initial environment was confirmed to be 16% and the initial average micro pressure difference of the pipeline network was 390 Pa. At the 0th second of the experimental timing, the doors of the three devices in each of the experimental and control groups were opened completely and kept open for 40 seconds before all doors were closed simultaneously. The system continuously recorded and extracted the global average micro pressure difference and maximum relative humidity characteristics of each group during the experimental period through the bus data acquisition system.

[0067]

[0068] From Table 1 and Appendix Figure 10It can be seen that: after the door is closed at the 40th second, the experimental group triggers the digital full-load opening command, causing the average micro pressure difference of the pipeline network to reach 894.7 Pa at the 45th second. The experimental group uses fluid driving force to open the branch valve of the corresponding equipment and discharge the humid gas. The highest relative humidity of the experimental group drops to 30.5% at the 110th second. The control group, due to the constant flow of gas supply, has a slow rise in pipeline pressure difference, resulting in a highest relative humidity of 48.2% at the 200th second.

[0069] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A liquid nitrogen self-venting biobank drying and pressure-maintaining device, characterized in that: It includes a liquid nitrogen refrigeration storage device (1), a compressor refrigeration storage device (2), and a drying device (3); the drying device (3) is connected to multiple sets of liquid nitrogen refrigeration storage devices (1) and compressor refrigeration storage devices (2), the drying device (3) can receive the drying gas from multiple sets of liquid nitrogen refrigeration storage devices (1), and the drying gas in the drying device (3) can dehumidify and dry multiple sets of compressor refrigeration storage devices (2).

2. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to claim 1, characterized in that: The drying device (3) includes a self-exhausting drying component (31); the drying gas in the multiple sets of liquid nitrogen refrigeration storage devices (1) dehumidifies the humid gas in the multiple sets of compressor refrigeration storage devices (2) through the self-exhausting drying component (31).

3. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to claim 2, characterized in that: The self-exhausting drying assembly (31) includes a receiving component (311), a filtering component (312), and a conveying component (313); the receiving component (311) is connected to the conveying component (313) through the filtering component (312), the receiving component (311) is connected to multiple sets of liquid nitrogen refrigeration storage devices (1), and the conveying component (313) is connected to multiple sets of compressor refrigeration storage devices (2).

4. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to claim 3, characterized in that: The receiving component (311) includes a receiving branch pipe (3111), a first one-way valve (3112), and a receiving main pipe (3113); the receiving main pipe (3113) is connected to multiple sets of receiving branch pipes (3111), and the receiving branch pipes (3111) are equipped with a first one-way valve (3112). The multiple sets of receiving branch pipes (3111) are connected to multiple sets of liquid nitrogen refrigeration storage devices (1).

5. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to claim 3, characterized in that: The conveying component (313) includes a conveying pipe (3131) and an exhaust pipe (3132); the conveying pipe (3131) is connected to the filter component (312) and multiple sets of compressor refrigeration storage devices (2) respectively; the dry gas conveyed by the conveying pipe (3131) dries the multiple sets of compressor refrigeration storage devices (2), and the exhaust pipe (3132) is connected to the multiple sets of compressor refrigeration storage devices (2), and the multiple sets of compressor refrigeration storage devices (2) discharge humid gas through the exhaust pipe (3132).

6. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to claim 5, characterized in that: The conveying pipe fitting (3131) includes a main conveying pipe (31311), a branch conveying pipe (31312), and a second valve (31313); the main conveying pipe (31311) is connected to multiple sets of branch conveying pipes (31312), and the branch conveying pipes (31312) are equipped with a second valve (31313). The multiple sets of branch conveying pipes (31312) are connected to the compressor refrigeration storage equipment (2).

7. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to claim 5, characterized in that: The exhaust pipe fitting (3132) includes an exhaust main pipe (31321), exhaust branch pipes (31322), and a third valve (31323); the exhaust main pipe (31321) is connected to multiple sets of exhaust branch pipes (31322), and the exhaust branch pipes (31322) are provided with a third valve (31323), and the multiple sets of exhaust branch pipes (31322) are connected to the compressor refrigeration storage device (2).

8. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to any one of claims 2 to 7, characterized in that: The liquid nitrogen refrigeration storage device (1) is also equipped with a micro positive pressure control module and a humidity module. The humidity module can detect the humidity of the liquid nitrogen refrigeration storage device (1). The micro positive pressure control module can control the dry gas in the liquid nitrogen refrigeration storage device (1) to dehumidify the compressor refrigeration storage device (2) through the self-exhausting drying component (31).

9. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to claim 3, characterized in that: The filtering component (312) includes a filter (3121) that can filter foreign matter in the dry gas in the receiving component (311).

10. The liquid nitrogen self-venting biobank drying and pressure-maintaining device according to any one of claims 2 to 7, characterized in that: The drying device (3) also includes a backup drying gas assembly (32), which can dehumidify and dry the compressor refrigeration storage device (2).

11. A method for drying and maintaining pressure in a liquid nitrogen self-venting biobank, using the liquid nitrogen self-venting biobank drying and pressure maintaining device as described in claim 1, characterized in that, Includes the following steps: The micro-positive pressure control module reads the feedback values ​​of humidity sensors and micro-differential pressure sensors in multiple sets of liquid nitrogen refrigeration storage devices (1) and compressor refrigeration storage devices (2) according to a set cycle; The average micro-pressure difference, minimum micro-pressure difference and maximum relative humidity characteristic values ​​of multiple sets of compressor refrigeration storage equipment (2) are extracted, and the operating status of the pipeline is determined by combining the micro-pressure difference feedback value of liquid nitrogen refrigeration storage equipment (1). Based on the determined pipeline operating status, calculate the gas source compensation intervention amount of the standby dry gas assembly (32) and generate the corresponding adjustment command signal; The adjustment command signal is sent to the solenoid valve of the standby dry gas assembly (32) to control its conduction state and adjust the gas flow rate discharged into the common header. Establish a fluid pressure difference within the common header; When the pressure on the liquid nitrogen refrigeration storage device (1) side is higher than the pressure on the common header side, the first check valve (3112) is opened; When the standby dry gas assembly (32) replenishes gas to the common header, making the pressure on the common header side higher, the first one-way valve (3112) is locked under the action of reverse pressure difference. The internal high-pressure dry gas drives the second valve (31313) to conduct to the compressor refrigeration storage device (2) and drives the third valve (31323) to discharge the humid gas.

12. The method for drying and maintaining pressure in a liquid nitrogen self-venting biobank according to claim 11, characterized in that, The specific steps for extracting feature quantities, determining operational status, and calculating compensation intervention quantities are as follows: From the feedback values ​​of each node of the compressor refrigeration storage device (2), the maximum relative humidity is extracted as the highest relative humidity characteristic quantity, the minimum micro pressure difference is extracted as the global minimum micro pressure difference, and the average value of the micro pressure difference is calculated as the global average micro pressure difference. If the highest relative humidity characteristic is greater than or equal to the preset high humidity alarm upper limit, it is determined to be a high humidity abnormal state. The gas source compensation intervention amount is set to the maximum design flux, a digital full-load start command signal is generated and the steady-state algorithm is overridden until the highest relative humidity characteristic continues to be lower than the high humidity reset threshold. If the highest relative humidity characteristic is less than the high humidity alarm upper limit, and the global minimum micro-pressure difference is less than or equal to the safe pressure holding lower limit, or the global average micro-pressure difference is less than the air pressure intervention trigger value, combined with the condition that the micro-pressure difference on the liquid nitrogen side is lower than the preset gas source availability threshold, it is determined to be a gas source attenuation state, and a prediction compensation calculation is triggered: The difference between the current global average micro-pressure difference and the historical value at the previous sampling time is calculated, and then divided by the time interval to obtain the pressure difference attenuation slope. The target pressure setting is multiplied by the single pressure deviation of the current global average micro pressure difference by a proportional gain coefficient, combined with the cumulative sum of historical pressure deviations in the sampling period by an integral gain coefficient, and then superimposed with the pressure difference attenuation slope multiplied by a differential gain coefficient. The dynamic gas source compensation intervention amount is calculated by logically summing the above three items. If the highest relative humidity characteristic value is less than the high humidity alarm upper limit value, and the global minimum micro pressure difference is greater than the safe pressure holding lower limit value, and the global average micro pressure difference is greater than or equal to the air pressure intervention trigger value, it is determined to be a normal pressure holding state. The air source compensation intervention amount is assigned to zero, and a zero opening adjustment command signal is generated to put the device in a passive pressure holding natural operation state.

13. The method for drying and maintaining pressure in a liquid nitrogen self-venting biobank according to claim 11, characterized in that, The physical evolution steps involved in establishing a fluid pressure difference, driving valves, and venting air within the common header include: During the process of establishing a fluid pressure difference in the common header, the configuration is based on the gas state equation. The fluid static pressure value inside the common header is composed of the initial pipeline filling pressure plus the cumulative definite integral of the difference between the gas mass inflow rate and outflow rate in the corresponding time period. This cumulative definite integral is directly proportional to the absolute temperature of the gas and inversely proportional to the effective volume. The high-pressure gas is conducted to the front end of the second valve (31313) or the third valve (31323) to form a pressure difference between the internal fluid static pressure and the external environmental back pressure. This pressure difference is multiplied by the effective force-bearing cross-sectional area to obtain the physical driving force. When the physical driving force is greater than the sum of the preload of the mechanical return spring inside the valve and the frictional resistance of the mechanical seal, the valve is driven to disengage from the sealing seat. When the high-pressure dry gas enters the compressor refrigeration storage device (2) through the second valve (31313), it uses the fluid pressure difference to generate mechanical compression and fluid purging effect on the wet and cold air mixed in the pipeline network, and pushes the humid gas along the exhaust branch pipe (31322) and the third valve (31323) into the external environment within the set fluid replacement response cycle.

14. The method for drying and maintaining pressure in a liquid nitrogen self-venting biobank according to claim 11, characterized in that, The specific method by which the micro-positive pressure control module performs signal acquisition and command output is as follows: The clock trigger unit inside the micro positive pressure control module synchronously sends power signals to each group of devices according to a set time period. After receiving the power signal, the sensors inside the devices return the environmental physical parameters at the current sampling time, which are then mapped to the underlying variable parameter set of the control model after analog-to-digital conversion. When the micro-positive pressure control module receives the zero-opening adjustment command signal, it cuts off the power supply to the excitation coil of the solenoid valve to keep it off. When an analog opening adjustment command signal is received, a pulse width modulation signal with a continuously adjustable duty cycle is output to adjust the opening and closing duty cycle of the solenoid valve per unit time. When a digital full-load start command signal is received, a continuous high-level drive signal is output to enable the solenoid valve to open the physical air passage in full-bore state.

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