Cold-chain logistics box and sealing control method thereof

Abstract

The invention discloses a cold-chain logistics box which is provided with a box body, a box door and a refrigeration unit and is characterized in that an elastic sealing strip and an inflatable sealing strip are arranged between the box body and the box door, a magnetic strip is arranged in the elastic sealing strip, a sealing system comprises the elastic sealing strip and the inflatable sealing strip, and the magnetic strip is arranged in the elastic sealing strip; the device further comprises an inflation valve, an air pump, a first air pressure sensor, a second air pressure sensor, a third air pressure sensor, a displacement sensor, a first temperature sensor, a second temperature sensor, a controller, a power-off opening valve and an energy accumulator. By means of multi-layer composite sealing and inflation pressure compensation, the ultra-low leakage rate, multi-layer redundancy, high reliability, long service life and ultra-wide temperature zone coverage are achieved, air tightness can still be kept in the ultra-low temperature environment, the cold leakage rate is smaller than 3% / h, real-time response, accurate compensation and energy efficiency optimization can be achieved, and the application range is wide. The problem that cold leakage of an inflatable sealing strip occurs under complex working conditions in a traditional sealing mode is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cold chain logistics equipment, and particularly to a cold chain logistics box and a sealing control method thereof. Background Art

[0002] A cold chain logistics box is a device used to keep goods at a low temperature or constant temperature during the logistics transportation process, and is widely used in industries such as food, medicine, and chemical industry. Its types include passive refrigeration, active refrigeration, and dry ice refrigeration, etc. For the cold chain logistics box of the active refrigeration type, a refrigeration unit is configured, which is mainly applicable to long-distance transportation, precise temperature control requirements, and can continuously refrigerate and maintain a constant temperature condition. However, the traditional cold chain logistics box has the following problems: (1) The sealing of the traditional active cold chain logistics box depends on a single rubber strip, and cold leakage (leakage rate > 10% / h) occurs due to the low-temperature shrinkage or long-term extrusion deformation of the box door or box body; (2) In a dynamic environment (such as when the change amount of the door gap becomes larger, pressure difference, sudden temperature change, etc.), it lacks the ability to adjust the adaptive sealing pressure, and there is a risk of sealing failure when power is off, and thus it cannot meet the requirements of low leakage rate (such as leakage rate ≤ 5% / h) for special materials (such as food, medicine, vaccines, etc.). Summary of the Invention

[0003] The present invention provides a cold chain logistics box to solve the technical problems that the sealing of the existing traditional cold chain box depends on a single rubber sealing strip, cold leakage (leakage rate > 10% / h) occurs due to the low-temperature shrinkage or long-term extrusion deformation of the box door or box body, it lacks the ability to adjust the adaptive sealing pressure in a dynamic environment (such as when the change amount of the door gap becomes larger, pressure difference, sudden temperature change, etc.), and there is a risk of sealing failure when power is off, and thus it cannot meet the requirements of low leakage rate for special materials (such as food, medicine, vaccines, etc.).

[0004] In order to achieve the above-mentioned purpose, the technical solution of the present invention is: a cold chain logistics box, comprising a box body, a box door and a refrigeration unit, characterized in that: an elastic sealing strip and an inflation sealing strip are arranged between the box body and the box door, and a magnetic strip is arranged in the elastic sealing strip; it also includes an inflation valve, an air pump, a first air pressure sensor, a second air pressure sensor, a third air pressure sensor, a displacement sensor, a first temperature sensor, a second temperature sensor and a controller; the first air pressure sensor is used to detect the pressure inside the cold chain logistics box and send a signal to the controller; the second air pressure sensor is used to detect the pressure outside the cold chain logistics box and send a signal to the controller; the third The air pressure sensor is used to detect the current pressure inside the inflatable sealing strip and send a signal to the controller; the displacement sensor is used to detect the change in the door gap between the box door and the box body and send a signal to the controller; the first temperature sensor is used to detect the temperature inside the cold chain logistics box and send a signal to the controller; the second temperature sensor is used to detect the temperature outside the cold chain logistics box and send a signal to the controller; the inflatable sealing strip is connected to the air pump pipeline through the inflation valve, and the controller is used to dynamically control the working status of the inflation valve or the air pump according to the obtained signal; the inflatable sealing strip is also connected to the accumulator pipeline by opening the valve through power off.

[0005] The above solution is adopted: First, since a magnetic strip is provided in the elastic sealing strip, the elastic sealing strip is in a compressed state (e.g., a compression rate of 20-30%) when the box door is closed, and the box body is quickly adsorbed by magnetic force. The strong magnetic force of the magnetic strip is utilized to adsorb the box body at the moment the box door is closed, eliminating the sealing of macroscopic gaps, thereby increasing the sealing speed, preventing the door gap from being misaligned due to transportation vibration, and resisting vibration and falling off. The elastic sealing strip has sufficient elasticity to fill the gap between the door and the box body, compensate for manufacturing tolerances and deformation, fill the deformation gap, compensate for box body processing errors, low-temperature shrinkage, buffer vibration impact, and process macroscopic gaps. The elastic material absorbs vibration energy and reduces sealing surface wear. Secondly, the sealing ring is expanded by inflating the inflatable sealing strip, filling the microscopic gaps and providing a tighter seal. Therefore, the technical problem that the existing traditional cold chain box sealing relies on a single rubber sealing strip, resulting in low-temperature shrinkage of the box door or box body or long-term extrusion deformation leading to cold leakage (leakage rate > 10% / h) can be solved. Secondly, in order to effectively address the problem of reduced sealing performance caused by temperature fluctuations, mechanical vibrations, deformation, power outages, etc. during the transportation of cold chain logistics boxes, the present invention also constitutes an inflation system for the inflatable sealing strip through an inflation valve, an air pump, a first pressure sensor, a second pressure sensor, a third pressure sensor, a displacement sensor, a power-off opening valve, an accumulator, and a controller. By real-time monitoring of parameters such as pressure, temperature, and door gap change amount, and dynamically adjusting the inflation pressure of the inflatable sealing strip according to the parameters, it can adapt to different environmental changes. For example: (1) When the temperature inside the box drops suddenly (such as -150°C), the gas inside the box will contract, resulting in a pressure drop. The dynamic adjustment system can immediately increase the pressure (for example, from 8 psi to 12 psi), offsetting the increased gap caused by the contraction of the elastic sealing strip (1), and achieving self-sealing compensation when the temperature drops suddenly; (2) When an accident occurs or the road is uneven and there is severe vibration (known from the change in δ), the inflation pressure can be controlled to increase, offsetting the instantaneous cold leakage caused by the vibration; the periodic cold leakage caused by vibration can be offset by the adaptive pressure compensation method (such as real-time compensation of the pressure fluctuations caused by temperature / vibration through a pressure sensor and a PID algorithm); (3) Since it is controlled in a dynamic change mode, the air pump is only started when a deviation in pressure (or temperature, etc.) is detected, which can save 40%-50% energy compared to the continuous gas supply mode; (4) Dynamic control can avoid overpressure (resulting in fatigue cracking) or underpressure (resulting in friction and wear) of the inflatable sealing strip for a long time, and can extend the service life of the inflatable sealing strip; (5) When a power outage occurs, the power-off opening valve (10) automatically switches to the accumulator for gas supply, becoming an emergency mode, avoiding the situation of insufficient pressure in the inflatable sealing strip after a sudden power outage. When a power outage occurs, the accumulator can still maintain a certain time (such as the inflation pressure ≥ 4 hours to meet the compliance requirements of the pharmaceutical cold chain).

[0006] Therefore, through the dynamic adjustment of the inflatable sealing strip, the inflation system of the present invention realizes real-time response, precise compensation, and energy efficiency optimization, and solves the pain point problem of cold leakage in the inflatable sealing strip of the traditional sealing system under complex working conditions.

[0007] Furthermore, the elastic sealing strip includes a connecting chuck, a transverse main body, and a deformable main body. A deformation cavity is formed inside by the enclosure of the transverse main body and the deformable main body; there is an inner folded lip on each side of the transverse main body; there is an arched part on each side of the deformable main body part, and a rectangular frame part is provided in the middle of the deformable main body part; the magnetic strip is arranged inside the rectangular frame part.

[0008] Furthermore, the width of the cross-section of the magnetic strip is 10-20 mm, the thickness is 3-5 mm, and the adsorption force is ≥ 50 N / m.

[0009] Furthermore, the power-off opening valve adopts a normally open solenoid valve.

[0010] Furthermore, the inflation valve adopts an electromagnetic proportional valve.

[0011] The present invention also discloses an inflation and sealing pressure control method, which uses the cold chain logistics box described in any one of the above technical solutions, and is characterized by including the following steps: S10. Obtain the change amount δ of the door gap of the cold chain logistics box, the temperature Tin inside the box, the temperature Tout outside the box, the pressure Pin inside the box, and the pressure Pout outside the box; S20. Calculate the target pressure Ptarget in the multimode; S30. Real-time adjust the air pump speed or the opening degree of the inflation valve through the PID algorithm; S40. When the power is cut off, the power-off opening valve opens, and the air supply is switched to the accumulator.

[0012] Furthermore, the formula relationship of the target pressure (P target ) in step S20 is: ; P base : The basic pressure required for static sealing; δ: The change amount of the door gap detected in real time; KT: Temperature-pressure conversion coefficient; r: Sealing material stiffness coefficient; n: Nonlinear index; ΔT: Temperature difference inside and outside the box = Tin - Tout; Pin: Pressure inside the box; Pout: Pressure outside the box; α: Differential pressure sensitivity coefficient.

[0013] Furthermore, the real-time adjustment of the air pump speed or the opening degree of the inflation valve through the PID algorithm in step S30 includes: S301. Initialize the control parameters: set the proportional coefficient Kp, the integral coefficient Ki, the differential coefficient Kd, and the maximum adjustment amount Umax; S302. Loop and execute the following steps: S3021. Real-time collect the current pressure value Pa(k) inside the inflation sealing strip; where, the Pa(k) represents the current pressure value at the kth sampling moment; S3022. Calculate the current pressure deviation value e(k) = = Ptarget - Pa(k), where Ptarget is the target pressure; S3033. Output the adjustment amount Δu(k) according to the incremental PID algorithm; ; Kp, Ki, Kd: Proportional coefficient, integral coefficient, differential coefficient; S3034. Limit the adjustment amount Δu(k) within the range of ±Umax; S4035. Output corresponding control of the inflation valve opening or the air pump speed according to the final adjustment amount Δu(k) to adjust the internal pressure of the inflatable sealing strip; S4036. Update the historical deviation value e(k - 1) = e(k), and wait to enter the next control cycle. Further, the sampling interval of the control cycle is Δt = 0.1 s; Further, the maximum adjustment amount Umax is used to prevent the instantaneous overload of the air pump or the inflation valve, and its value range is 5% - 20%.

[0014] First, due to the elastic compression strip of the elastic sealing strip in the present invention compensating for larger gaps and deformations, it can adapt to different assembly errors; while the inflatable sealing strip deals with finer gaps and dynamically adjusts to cope with environmental changes, complementing each other to ensure reliability under different working conditions. For example, when encountering vibrations during transportation, the elastic sealing strip can absorb the vibrations, while the inflatable sealing strip realizes dynamic pressure adjustment to prevent seal failure. When the temperature changes, the inflatable sealing strip can compensate for the thermal expansion and contraction of the material to maintain the seal; Second, the present invention can improve the redundancy of the sealing system. If a certain layer fails temporarily, other layers can still provide a certain degree of sealing, reducing the overall failure risk. For example, if the inflation system fails to work due to a fault or power outage, the elastic sealing strip with a magnetic strip can still maintain a basic seal until the problem is solved; Third, the present invention constitutes an inflation system for dynamically controlling the inflatable sealing strip through an inflation valve, an air pump, a first air pressure sensor, a second air pressure sensor, a third air pressure sensor, a displacement sensor, a first temperature sensor, a second temperature sensor, and a controller; when the temperature inside the box changes in a dynamic environment (such as when the change amount of the door gap becomes larger, the pressure difference, the temperature changes suddenly, etc.), the pressure can be dynamically adjusted through the inflation system to maintain the seal. At the same time, the inflatable seal can cope with the microscopic unevenness (Ra ≤ 10 μm), and form a global seal through the "one static and one dynamic" combination of the elastic sealing strip and the inflatable sealing strip; Fourth, the present invention can achieve the complementary of their respective sealing functions, providing a multi-level and dynamically adaptable sealing solution, which is suitable for the complex and changeable cold chain transportation environment, improving the reliability and service life of the seal. By adopting magnetic attraction, elastic compression and inflatable sealing, "magnetic attraction + elastic compression + inflation" composite sealing can be realized, so that the leakage rate of the cold chain logistics box at low temperature can be controlled within < 3% / h; through the collaborative design of the magnetic, elastic and inflatable three layers, the cold chain logistics box realizes full-scale sealing from millimeter level to micron level, which is beneficial to the high-standard logistics transportation of modern temperature-sensitive materials; Fifthly, the cold chain logistics box of the present invention adopts a composite sealing structure, which can effectively reduce leakage and the influence of the external environment. By combining the multi-modal target pressure Ptarget with the real-time adjustment of the air pump speed or the opening degree of the inflation valve through the PID algorithm, the upgrade from "passive leakage prevention" to "active leakage prevention" can be achieved, improving the adaptability to dynamic environments, control accuracy, and stability. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic structural diagram of a cold chain logistics box in the present invention.

[0015] Figure 2 is Figure 1 the enlarged view of part A in

[0016] Figure 3 is a cross-sectional view of the elastic sealing strip.

[0017] Figure 4 is the cross-sectional view of the inflatable sealing strip before inflation.

[0018] Figure 5 is the cross-sectional view of the inflatable sealing strip after inflation.

[0019] Figure 6 is the working principle diagram of the inflation system in the present invention.

[0020] Figure 7 is the flowchart of the operation of a method for controlling the inflation seal pressure in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The present invention will be further described below in conjunction with the drawings and embodiments: Embodiment 1: Refer to Figure 1-7 , a cold chain logistics box, which has a box body, a box door, a refrigeration unit, and an inflation system. The refrigeration unit is used to control the temperature of the cold chain logistics box during transportation and storage and maintain a low-temperature environment; specifically, the box body, the box door, and the refrigeration unit can all adopt existing technologies, so they will not be elaborated here.

[0022] The key lies in: An elastic sealing strip 1 and an inflatable sealing strip 3 are provided between the box body and the box door, and a magnetic strip 2 is arranged inside the elastic sealing strip 1. Refer to Figure 2 .

[0023] Refer to Figure 3 , in this embodiment, the elastic sealing strip 1 includes a connecting chuck 1-1, a transverse main body 1-2, and a deformed main body 1-3. A deformation cavity 1-4 is formed inside by the enclosure between the transverse main body 1-2 and the deformed main body 1-3; One inner folding lip 1-21 is provided on each side of the transverse main body 1-2; One arched part 1-31 is provided on each side of the deformed main body part 1-3, and a rectangular frame part 1-32 is provided in the middle of the deformed main body part 1-3; The magnetic strip 2 is arranged inside the rectangular frame part 1-32.

[0024] The elastic sealing strip 1 is preferably made of silicone or EPDM. Its compression deformation (20%-30% strain) compensates for processing errors and low-temperature shrinkage, filling gaps of at least 0.1mm. The inflatable sealing strip 3 covers even microscopic surface irregularities ≤0.1mm, achieving full sealing. If any sealing layer fails partially, the remaining layers can still maintain basic sealing performance (for example, after the inflatable sealing layer fails, the leakage rate of the magnetic and elastic layers is ≤5% / h).

[0025] Specifically, the width of the lateral body 1 - 2 and the deformation body 1 - 3 as a whole is 25-30 mm, the thickness is 8-12 mm, and the Shore hardness is 40±5.

[0026] See Figure 2 , wherein the horizontal body 1-2 is used to fit with the door or the installation surface of the box body; the deformable body 1-3 is used to fit with the box body or the door or the contact surface.

[0027] See Figure 2 The transverse main body 1-2 of the elastic sealing strip 1 is used to fit with the mounting surface to provide basic sealing support, while the inner folded lips 1-21 on both sides of the transverse main body may be used to strengthen the two mounting grooves with the mounting surface and be embedded in them to maintain stability, greatly improving the edge and overall fitting effect and sealing performance with the mounting surface.

[0028] See Figure 3 The deformable main body 1-3 of the elastic sealing strip 1 serves as the deformation and compression part, and after compression and deformation, it elastically contacts the contact surface. At the same time, a curved arch portion 1-31 and a rectangular frame portion 1-32 are respectively provided on both sides to form three-segment contact with the contact surface. The magnetic strip 2 is arranged in the rectangular frame portion 1-32 and is adsorbed and sealed with the contact surface. The transverse main body 1-2 and the deformable main body 1-3 are surrounded to form a deformation cavity 1-4 inside; this enables the sealing strip to have good elastic deformation ability and extrusion space when under pressure, thereby enhancing the sealing effect to adapt to different sealing gaps and contact surface shapes and roughness conditions.

[0029] See Figure 3, with the above structural design, the elastic sealing strip 1 can achieve multi - part collaborative sealing. Through the left and right arched parts 1 - 31 of the deformable main body 1 - 3, the middle rectangular frame part 1 - 32, the transverse main body 1 - 2 and its inner - folded lip part 1 - 21, it contacts the sealing interface from different directions and angles, which can comprehensively improve the overall sealing effect and the anti - seismic and anti - detachment performance; at the same time, structures such as the left and right arched parts 1 - 31, the left and right inner - folded lip parts 1 - 21, and the deformation cavity 1 - 4 enable the elastic sealing strip 1 to undergo elastic deformation when subjected to external extrusion, adapt to different installation clearances and the unevenness of the sealing surface, and return to its original state after the pressure is removed. Meanwhile, it can maintain long - term stable sealing performance, enabling it to give full play to the advantages of each part in a complex usage environment and improve the overall sealing reliability.

[0030] See Figure 3 , specifically, the width of the cross - section of the magnetic strip 2 is 10 - 20 mm, the thickness is 3 - 5 mm, and the adsorption force ≥ 50 N / m. This can ensure that there is sufficient adsorption force between the elastic sealing strip 1 and the fitting surface of the box door or the box body and maintain sealing contact, generating anti - detachment pressure.

[0031] See Figure 2 , during use, when the box door is closed and the door lock is locked, the elastic sealing strip 1 is compressed and deformed by the box body and the box door, and its compression rate is required to be 20 - 30%. The elastic sealing strip 1 can elastically compensate for the cold shrinkage deformation or manufacturing tolerance of the box body or the box door, prevent cold air from leaking, and resist vibration and detachment.

[0032] Among them, the volume of the box body is 50 L, the length L of the elastic sealing strip 1 and the inflatable sealing strip 3 is 2 m, and the total adsorption force F of the magnetic strip is 100 N. The total length of the magnetic strip 2 is also 2 m, so the total adsorption force is equal to 100 N, which is equivalent to 10 kg - force.

[0033] See Figure 6 , the inflation system includes an inflation valve 4, an air pump 5, a first pressure sensor 6, a second pressure sensor 7, a third pressure sensor 8, a displacement sensor 9, a first temperature sensor 10, a second temperature sensor 11 and a controller 12; Among them, the first pressure sensor 6 is used to detect the internal pressure Pin of the cold - chain logistics box and send a signal to the controller 12. The model can be selected as MS5803 - 14BA.

[0034] Among them, the second pressure sensor 7 is used to detect the external pressure Pout of the cold - chain logistics box and send a signal to the controller 12; the model can be selected as MS5803 - 14BA.

[0035] The third air pressure sensor 8 is used to detect the current pressure Pa in the inflatable sealing strip 3 and send a signal to the controller 12; the optional model is MS5803-14BA.

[0036] The displacement sensor 9 is used to detect the change in the gap δ between the door and the box body and send a signal to the controller 12; the model that can be used is LVDT-050.

[0037] Among them, the first temperature sensor 10 is used to detect the temperature Tin inside the cold chain logistics box and send a signal to the controller 12; the optional model is PT1000.

[0038] Among them, the second temperature sensor 11 is used to detect the temperature Tout outside the cold chain logistics box and send a signal to the controller 12; the optional model is PT1000.

[0039] The inflatable sealing strip 3 is connected to the air pump 5 through the inflatable valve 4, and the controller 12 is used to dynamically control the working state of the inflatable valve 4 or the air pump 5 according to the acquired signal; the inflatable sealing strip 3 is also connected to the accumulator 14 through the power-off opening valve 13. Figure 6 The inflation valve 4, air pump 5, first air pressure sensor 6, second air pressure sensor 7, third air pressure sensor 8, displacement sensor 9, first temperature sensor 10, second temperature sensor 11, and power-off opening valve 13 are all connected to the controller 12 circuit.

[0040] Specifically, the controller may be of the STM32H7 model.

[0041] Preferably, the power-off opening valve 13 is a normally open electromagnetic valve. Under normal conditions, the controller 12 controls the power-off opening valve 13 to be in a closed position, and when power is off, the normally open electromagnetic valve is in a normally open position and is freely opened.

[0042] The pressure maintenance time after power failure is calculated as follows: For example, the accumulator capacity Vacc = 2L, the maximum pressure Pmax = 15ps, the minimum pressure Pmin = 8psi; the system leakage rate Qleak = 0.05L / min, that is, the volume of fluid leaked from the cold chain logistics box system per minute. Then, we calculated t=280min, which means the pressure maintenance time after power failure is 4.67 h.

[0043] Preferably, the inflation valve 4 is an electromagnetic proportional valve.

[0044] At the beginning, the air pump starts, and the inflatable sealing strip expands to fill the remaining microscopic gaps. After the pressure of the inflatable sealing strip stabilizes (for example, when it is detected that the current pressure Pa rises to the target pressure value Pset = 6 ± 0.1 psi and remains unchanged for 5 s), the pump automatically stops.

[0045] In this embodiment, first, since a magnetic strip is provided in the elastic sealing strip 1, when the box door is closed, the elastic sealing strip 1 is in a compressed state (for example, the compression rate is 20 - 30%), and it quickly adsorbs the box body through magnetic force. By using the strong magnetic force of the magnetic strip 2, it adsorbs instantly when the box door is closed, eliminating the sealing of macroscopic gaps, which can improve the sealing speed, prevent the misalignment of the door seams caused by transportation vibration, and resist vibration and shedding; and the elastic sealing strip 1 has sufficient elasticity to fill the gap between the box door and the box body, compensating for manufacturing tolerances and deformations, filling the deformation gap, compensating for the machining errors of the box body, low-temperature shrinkage, buffering vibration and shock, dealing with macroscopic gaps, and the elastic material absorbs vibration energy, reducing the wear of the sealing surface; second, the inflatable sealing strip is inflated to expand the sealing ring, filling the microscopic gaps and providing a tighter seal. Therefore, it can solve the technical problem that the existing traditional cold chain box depends on a single rubber sealing strip for sealing, resulting in cold leakage (leakage rate > 10% / h) due to the low-temperature cold shrinkage or long-term extrusion deformation of the box door or the box body. Secondly, in order to effectively deal with the problems of decreased sealing performance caused by temperature fluctuations, mechanical vibrations, deformations, power outages, etc. during the transportation of the cold chain logistics box. The present invention also constitutes an inflation system for the inflatable sealing strip 3 through an inflation valve 4, an air pump 5, a first air pressure sensor 6, a second air pressure sensor 7, a third air pressure sensor 8, a displacement sensor 9, a power-off opening valve 10, an accumulator 11 and a controller 12. By real-time monitoring of parameters such as pressure, temperature, and the change amount of the door seam, and dynamically adjusting the inflation pressure of the inflatable sealing strip 3 according to the parameters, it can adapt to different environmental changes.

[0046] For example: (1) When the temperature inside the box drops suddenly (such as -120 °C), the gas inside the box body will contract, resulting in a pressure drop. The dynamic adjustment system can immediately increase the pressure (for example, from 8 psi to 12 psi), offsetting the increase in the gap caused by the contraction of the elastic sealing strip 1, and realizing self-sealing compensation when the temperature drops suddenly: (2) When an accident occurs or the road is uneven and there is severe vibration (known from the change in the δ value), the inflation pressure can be controlled to increase, offsetting the instantaneous cold leakage caused by the vibration; for the periodic cold leakage caused by vibration, it can be offset by the adaptive pressure compensation (such as real-time compensation of the pressure fluctuations caused by temperature / vibration through the air pressure sensor and the PID algorithm) method to offset the effects of vibration and temperature; (3) Since it is controlled in a dynamic change mode, the air pump is only started when a deviation in pressure (or temperature, etc.) is detected. Compared with the continuous gas supply mode, it can save 40% - 50% of energy; (4)Dynamic control can avoid overpressure (resulting in fatigue cracking) or underpressure (resulting in friction and wear) of the inflatable sealing strip for a long time, and can extend the service life of the inflatable sealing strip; (5)When power is off, the power-off open valve (normally open solenoid valve) loses the electromagnetic suction effect and automatically switches to the accumulator for air supply, becoming an emergency mode, avoiding the situation of insufficient pressure in the inflatable sealing strip after sudden power-off. When power is off, the accumulator still maintains a certain time (such as the inflation pressure ≥ 4 hours to meet the compliance requirements of the pharmaceutical cold chain). Comparison Dimension Single Seal (Rubber Strip) Single Inflatable Seal Composite Seal (Magnetic + Elastic + Inflatable) Sealing Performance Higher Leakage Rate (10% - 15% / h) Medium Leakage Rate (5% - 8% / h) Extremely Low Leakage Rate (1% - 3% / h) Environmental Adaptability Narrow Temperature Range (-20°C to +60°C) Relatively Wide Temperature Range (-40°C to +80°C) Extremely Wide Temperature Range (-120°C to +120°C) Vibration Resistance Poor, vibration easily leads to seal failure Average, dynamic pressure compensation adjustment is required Excellent, the influence of vibration is offset by inflatable pressure compensation Redundancy Design No redundancy, high risk of single-point failure No redundancy, relying on the stability of the inflation system Multi-layer redundancy, basic sealing can still be maintained even if any sealing layer fails Service Life Short (2 - years) Medium (3 - 5 years) Long (8 - 10 years) Typical Application Scenarios Normal Temperature and Fresh Food Distribution, Short-distance Transportation Medium and Low Temperature Medical Transportation, Community Group Buying Ultra-low Temperature Transportation, Long-distance Transportation of Vaccines / Biological Samples Energy Efficiency No Energy Consumption Requirement Continuous gas supply is required, high energy consumption (1.0 - 1.5 kWh / day) Adjustable on demand, significant energy saving (0.5 - 0.8 kWh / day) Through the above composite design, through multi-layer coordination and inflation pressure compensation, the present invention achieves extremely low leakage rate, multi-layer redundancy, high reliability, long life and ultra-wide temperature range coverage, which is the optimal solution for high-end cold chain logistics scenarios such as medicine and food research. At the same time, the cold chain logistics box can still maintain airtightness in extremely low temperature environments (such as ΔT = -100 °C), and the cold leakage rate < 3% / h, far exceeding the performance of the existing single-layer sealing structure (usually > 10% / h).

[0047] Therefore, the inflation system of the present invention realizes real-time response, precise compensation and energy efficiency optimization through dynamic adjustment of the inflatable sealing strip, and solves the pain point problem of cold leakage of the inflatable sealing strip in the traditional sealing system under complex working conditions.

[0048] Example 2: Refer to Figure 6-7 , an inflatable seal pressure control method, using the cold chain logistics box described in Example 1, which includes the following steps: S10. Obtain the door gap change amount δ, the temperature Tin inside the box, the temperature Tout outside the box, the pressure Pin inside the box and the pressure Pout outside the box of the cold chain logistics box; S20. Calculate the target pressure Ptarget in the multi-modal state; S30. Adjust the air pump speed or the opening degree of the inflation valve in real time through the PID algorithm; S40. When the power is off, the power-off open valve opens and switches to the accumulator for air supply.

[0049] Among them, in step S10, specifically, each of the above sensors collects signals once every Δt seconds (such as 0.1 s), and then converts them into digital signals through an A / D converter and sends them to the controller.

[0050] Among them, the formula relationship of the target pressure (P target ) in step S20 is: ; P base : The basic pressure required for static sealing; δ: The door gap change amount (mm) detected in real time; KT: Temperature-pressure conversion coefficient; r: Stiffness coefficient of the sealing material n: Nonlinear exponent; ΔT: Temperature difference between inside and outside of the box = Tin - Tout; Pin: Pressure inside the box (kPa or psi); Pout: Pressure outside the box (kPa or psi); α: Differential pressure sensitivity coefficient.

[0051] Wherein, is the temperature compensation term (absolute value), is the differential pressure compensation term (absolute value), is the compensation term for the change in the door gap (absolute value), and the influence weight analysis of each compensation term: compensation term for the change in the door gap > temperature compensation term > differential pressure compensation term. The compensation term for the change in the door gap is affected by factors such as filling the door gap (e.g., transportation vibration); the temperature compensation term offsets the influence of thermal expansion and contraction effects, and the differential pressure compensation term balances the influence of the internal and external differential pressures. The following is an example: For example, it is determined according to the material and performance of the inflatable sealing strip (such as silicone): r = 26.8, KT = 0.01, n = 1.5, α = 0.2, Pbase = 6 psi.

[0052] First, input the collected parameters: δ = 0.2 mm (positive for increase, negative for decrease), Tin = -80 °C, Tout = 20 °C, Pin = 101 kPa, Pout = 80 kPa (when the altitude increases, Pout decreases, forming a negative pressure); Calculate the target pressure Ptarget: Differential pressure compensation term = ∣0.2 * (101 - 80) ∣ = 4.2 kPa ≈ 0.6 psi; Temperature compensation term = ∣0.01 * (-80 - 20) ∣ = 0.01 * 100 = 1 psi; Compensation term for the change in the door gap = ∣26.8 * (0.2) 1.5 ∣≈ 2.4 psi; Target pressure Ptarget = 6 + 0.6 + 1 + 2.4 = 10 psi.

[0053] Specifically, in step S30, the real-time adjustment of the air pump speed or the opening degree of the inflatable valve by the PID algorithm includes: S301. Initialize the control parameters: set the proportional coefficient Kp = 0.8, the integral coefficient Ki = 0.05, the differential coefficient Kd = 0.1, and the maximum adjustment amount Umax = 10%; S302. Loop and execute the following steps: S3021. Collect the current pressure value Pa(k) inside the inflatable seal strip in real time, where Pa(k) represents the current pressure value at the k-th sampling moment. S3022. Calculate the current pressure deviation value e(k) = Ptarget - Pa(k), where Ptarget is the target pressure. S3033. Output the adjustment amount Δu(k) according to the incremental PID algorithm. ; Kp, Ki, Kd: proportional coefficient, integral coefficient, derivative coefficient. S3034. Limit the adjustment amount Δu(k) within the range of ±Umax. S4035. Output the corresponding control of the opening degree of the inflatable valve or the rotational speed of the air pump according to the final adjustment amount Δu(k) to adjust the pressure inside the inflatable seal strip. S4036. Update the historical deviation value e(k - 1) = e(k), and wait to enter the next control cycle. The sampling interval of the control cycle is Δt = 0.1s. Among them, the maximum adjustment amount Umax is used to prevent the instantaneous overload of the air pump or the inflatable valve, and its value range is 5% - 20%. In this example, the maximum adjustment amount Umax is taken as 10%. In this way, by setting the change limit of the maximum adjustment amount Umax, the instantaneous overload of the air pump or the inflatable valve can be effectively prevented, the service life of the equipment can be extended, and the equipment failure and maintenance costs caused by overload can be reduced. [[ID=…]]

[0054] Among them, through the incremental PID algorithm, the control amount increment is calculated according to the pressure error, and the precise adjustment of the pressure inside the inflatable seal strip can be realized, and the pressure can be maintained stable near the target value.

[0055] Among them, the output direction of the control amount increment Δu(k) is determined by the sign of the pressure error e(k). A positive value increases the pressure, and a negative value relieves the pressure. The logic is clear and reasonable, and the control direction is clear, ensuring that the pressure control operation meets the actual requirements; and then by executing the control steps in a cycle with a sampling interval of Δt = 0.1s, the pressure data and the control amount are updated in real time, and the pressure change can be responded to in a timely manner, realizing the continuous and stable control of the pressure of the inflatable seal strip.

[0056] For example, when calculating the target pressure Ptarget = 10 psi in the multi-modal state Initial state: Pa(0) = 8 psi, Ptarget = 10 psi, e(0) = Ptarget - Pa(0) = 2 psi. The process of incremental PID adjustment is as follows (sampling period Δt = 0.1s) in the following table (Table 2): ; As can be seen from the above table, the adjustment time can be achieved to be 0.4 s (from 8 psi to 10 psi), with an overshoot of 0%; the steady-state error is ±0.1 psi.

[0057] Index Switch Control Traditional PID This Embodiment Adjustment Time (s) >5.0 1.2 0.4 Pressure Fluctuation (psi) ±2.0 ±0.5 ±0.1 Energy Consumption (kWh / day) 1.5 1 0.7 Index Traditional Single-mode Control Multi-mode + Incremental PID Dynamic Regulation Improvement Effect Leakage Rate 5%-10% / h 1%-3% / h Reduced by 70% - 90% Response Speed 2 - 5 seconds 0.5 - 1 second Improved by 2 - 10 times Energy Consumption High (continuous full load) Low (adjustable on demand) Energy Saving of 40% - 50% Environmental Adaptability Can only be optimized for a single working condition Full Working Condition Coverage (-196°C - +80°C) Extended Application Scenarios by 5 times The method of the present invention combines parameters such as temperature, vibration, and pressure difference to correct Ptarget, reducing the influence of single-sensor error on control. Moreover, the PID only starts to adjust when a pressure deviation is detected. Compared with continuous full-load operation, the energy consumption of the air pump can be greatly reduced. At the same time, dynamic pressure management avoids long-term overpressure (resulting in fatigue cracking) or underpressure (resulting in friction and wear) of the sealing ring, which can extend its service life.

[0058] The method of the present invention calculates the target pressure Ptarget under multimodal conditions, integrates multi-sensor data such as temperature, vibration, and pressure difference, and dynamically adjusts the target pressure in real time, enabling dynamic change environments such as low-temperature compensation and vibration cancellation. For example, when the temperature inside the box drops suddenly, Ptarget can be automatically increased to offset the sealing contraction effect; when transportation vibration is detected and the change amount of the door gap becomes larger, Ptarget can be automatically increased for sealing compensation, reducing cold leakage. At the same time, an incremental PID is adopted for fast response. According to the calculated current pressure deviation value e(k) = Ptarget - Pa(k), the rotational speed of the air pump or the opening increment of the inflation valve is calculated in real time to ensure that the pressure quickly converges to the target value, with an adjustment time < 1 s, and the leakage rate is controlled < 3% / h. Through real-time cyclic control, precise adjustment of the sealing target pressure (error ≤ ±0.1 psi) is achieved, and the inflation pressure is dynamically adjusted to ensure that the inflatable sealing strip 3 always fits the box body or the box door, meeting the technical requirement that the leakage rate is always < 3% / h.

[0059] The sealing structure and control method of the cold chain logistics box of the present invention combine composite sealing and incremental PID dynamic adjustment, achieving the technical effects of high sealing performance, strong environmental adaptability, long service life, and low energy consumption, and upgrading the traditional passive leak prevention to active adjustment, providing a highly reliable and low-cost temperature-controlled transportation solution for fields such as medicine, vaccines, and scientific research. At the same time, it also solves the problems of slow response, large overshoot, and poor robustness of the traditional sealing system under complex working conditions.

[0060] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A cold chain logistics box, comprising a box body, a door, and a refrigeration unit, characterized in that: An elastic sealing strip and an inflatable sealing strip are provided between the box body and the box door, and a magnetic strip is provided inside the elastic sealing strip; It also includes an inflation valve, an air pump, a first air pressure sensor, a second air pressure sensor, a third air pressure sensor, a displacement sensor, a first temperature sensor, a second temperature sensor and a controller; the first air pressure sensor is used to detect the pressure inside the cold chain logistics box and send a signal to the controller; the second air pressure sensor is used to detect the pressure outside the cold chain logistics box and send a signal to the controller; the third air pressure sensor is used to detect the current pressure in the inflation seal strip and send a signal to the controller; the displacement sensor is used to detect the change in the door gap between the box door and the box body and send a signal to the controller; the first temperature sensor is used to detect the temperature inside the cold chain logistics box and send a signal to the controller; the second temperature sensor is used to detect the temperature outside the cold chain logistics box and send a signal to the controller; the inflation seal strip is connected to the air pump pipeline through the inflation valve, and the controller is used to dynamically control the working state of the inflation valve or the air pump according to the acquired signal; the inflation seal strip is also connected to the accumulator pipeline by turning off the power to open the valve.

2. The cold chain logistics box according to the claim is characterized in that: The elastic sealing strip includes a connecting clamp, a transverse body and a deformable body, and a deformation cavity is formed inside the transverse body and the deformable body; an inner folded lip portion is provided on each side of the transverse body; an arch portion is provided on each side of the deformable body, and a rectangular frame portion is provided in the middle of the deformable body; the magnetic strip is arranged in the rectangular frame portion.

3. The cold chain logistics box according to claim 1 or 2, characterized in that: The width of the magnetic strip cross section is 10-20 mm, the thickness is 3-5 mm, and the adsorption force is ≥50 N / m.

4. The cold chain logistics box according to claim 1, characterized in that: The power-off opening valve (13) is a normally open electromagnetic valve.

5. A cold chain logistics box according to claim 1, characterized in that: The inflation valve adopts an electromagnetic proportional valve.

6. An inflatable sealing pressure control method, which uses the cold chain logistics box described in any one of claims 1-5, and is characterized in that, The following steps are involved: S10. Obtain the door gap change δ, the temperature inside the box Tin, the temperature outside the box Tout, the pressure inside the box Pin, and the pressure outside the box Pout of the cold chain logistics box; S20, calculating the target pressure Ptarget under the multi-mode; S30, real-time adjustment of the air pump speed or the inflation valve opening through the PID algorithm; S40: When the power is cut off, the power-off valve opens and switches to supplying gas to the accumulator.

7. The cold chain logistics box according to claim 6, characterized in that: In step S20, the formula relationship of the target pressure (P target ) is as follows: P base : the basic pressure required for static sealing; δ: Real-time detection of door gap change; KT: temperature-pressure conversion coefficient; r: sealing material stiffness coefficient; n: nonlinear index; ΔT: Temperature difference between inside and outside the box = Tin − Tout; Pin: pressure inside the box; Pout: pressure outside the box; α: pressure difference sensitivity coefficient.

8. A pneumatic seal pressure control method according to claim 7, characterized in that: The step S30 of adjusting the air pump speed or the inflation valve opening in real time by using the PID algorithm includes: S301, initializing control parameters: setting the proportional coefficient Kp, integral coefficient Ki, differential coefficient Kd and maximum adjustment amount Umax; S302, loop through the following steps: S3021. Collect the current pressure value Pa(k) inside the inflatable sealing strip in real time; wherein Pa(k) represents the current pressure value at the kth sampling moment; S3022. Calculate the current pressure deviation value e(k) = Ptarget - Pa(k); where Ptarget is the target pressure. S3033. Output the adjustment amount Δu(k) according to the incremental PID algorithm; ; Kp, Ki, Kd: proportional coefficient, integral coefficient, derivative coefficient; S3034. Limit the adjustment amount Δu(k) within the range of ±Umax. S4035. Output the corresponding control of the inflation valve opening or the air pump speed according to the final adjustment amount Δu(k) to adjust the pressure inside the inflatable seal strip. S4036. Update the historical deviation value e(k - 1) = e(k), and wait to enter the next control cycle.

9. The inflatable seal pressure control method according to claim 8, wherein: The sampling interval of the control cycle is Δt = 0.1 s.

10. A pneumatic sealing pressure control method according to claim 8, characterized in that: The value range of the maximum adjustment amount Umax is 5% - 20%.

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