Development Of Vehicle Temperature Monitoring System For Vaccine Cold Chain Transportation

Vaccine is a commonly used temperature-sensitive immune drug,its whole life cycle cold chain temperature is generally required to be within 2~8?,exceeding this range can have a serious impact on vaccine quality.This paper focuses on the transportation link of vaccine cold chain which is most prone to over temperature during its whole life cycle,studied and analyzed the temperature distribution characteristics in the incubator and refrigerated compartment,designed and developed a set of vehicle temperature measuring system for vaccine cold chain transportation.The system includes a temperature measurement module and a communication monitoring platform,which can monitor,store and upload the multi-point temperature in the incubator and refrigerated compartment,to ensure the temperature monitoring requirements of cold chain storage and transportation of vaccines.The main work and achievements of this paper are as follows:1.Studied the temperature distribution characteristics in the incubator and refrigerated compartment,and the best temperature measurement points for refrigerated storage compartment of vaccines can be reasonably selected.According to internal structure of the incubator and the cold storage compartment and the way of refrigeration and heat preservation,the use of ANSYS software to establish the incubator and refrigerated compartment finite element model,and FLUENT software is used to calculate the internal temperature field of the incubator and refrigerated compartment,and obtain the internal temperature distribution.The accuracy of the simulation model is verified by testing the internal temperature field of the incubator in the laboratory environment.Through the simulation results,the specific number and optimal location distribution of temperature measuring points in the insulation box and refrigerated compartment are determined.2.Reasonable selection of temperature sensitive sensors and low power devices,through circuit design and optimization of sampling frequency,developed a special low-power temperature measurement module suitable for long-term use in cold chaintransportation of vaccines.Through the actual temperature comparison test,the average temperature measurement error of the module within of 2~8? and 0~20?the extended temperature range is within ±0.3?,which conforms to the provisions of the specifications for storage and transportation management of vaccines that the temperature measurement error is within ±0.5?.By designing ZigBee communication circuit and radio frequency antenna,the module has ZigBee communication function.After completing the PCB design of the module,the measurement calculation shows that the length and width of the module are about 39 mm and 31 mm,and the cost is about 43 yuan,which meets the design requirements of miniaturization of structure and low cost of hardware.3.Designed and developed an on-board temperature monitoring platform that is compatible with the special temperature measurement module,realizing the functions of synchronous reception of cold storage temperature,real-time monitoring,background storage and over-temperature alarm.The ZigBee technology is used to realize network communication between multiple modules and temperature receivers.To ensure the safety of temperature control in cold chain transportation of vaccines,special warning of low temperature at 3 and high temperature at 7 is provided for the management to monitor,analyze and deal with the problem in time.According to the laboratory and transport vehicle tests,the module power consumption is 0.29 J,and the communication success rate of the system under non-line-of-sight condition is100%,which meets the technical requirements of temperature monitoring in cold chain transportation of vaccines.