基于小型脉冲管制冷机的计量用低温恒温器设计与性能研究OA

When metrology laboratories employ the comparative method in cryogenic calibration systems,the thermostat frequently utilizes cryogenic fluid as the cold source.This kind of thermostat has the defects of large consumption of cryogenic fluid,short durations of single constant temperature maintenance and inconvenience for use in non-fixed places.These factors result in high operating costs and fail to meet the needs of rapid and continuous calibration of thermometers in industrial production.To address these issues,this study introduces a system that uses a small pulse tube refrigerator as the cold source and establishes a heat transfer and control model to achieve rapid evaluation of PID parameters.The system's well thermostatic structure is used to optimize the adiabatic performance of the system.The system achieves continuous temperature control in a wide temperature range of 90～290 K.The temperature fluctuation of the system is less than±0.030 K/30 min and the axial temperature uniformity is better than 0.010 K,fulfilling the traceability requirements of conventional industrial-grade cryogenic temperature sensors below 200 K.