Research On The Detection System Of Thermostatic Refrigerant Expansion Valves

In recent years,with the rising popularity of air conditioning,people have higher requirement on the performance of the air conditioning.As one of four major components in air conditioning refrigerating system,the performance of the thermal expansion valve will directly affect the operation of the air conditioning system.The performance of the thermal expansion valve is good or bad,which is mainly evaluated by some parameters,such as the gas tightness,internal leakage,working life and static superheat.At present,the equipment for testing the above several parameters exist some defects,such as the low degree of automation,low precision,complicated detection process and high expenses.So this paper proposes the internal leakage detection based on the principle of direct pressure and the gas tightness based on the principle of differential external pressure,and improves the detection scheme for the working life of the thermal expansion valve.Through the theoretical analysis and research,design the testing air path for the thermal expansion valve,built the detection platform for testing the internal leakage of the thermal expansion valve and the detection platform for testing the gas tightness and working life of the thermal expansion valve,do some experimental research and evaluate the performance of the test platform.The main research contents of this article including:(1)Through analyzing characteristics of the structure and working of the thermal expansion valve and the principle of the direct pressure and the differential external pressure,design the testing air path of the internal leakage detection based on the principle of direct pressure and the gas tightness based on the principle of differential external pressure.Improve the testing scheme of the working life of the thermal expansion valve in the current standard and design the air path of the working life detection.(2)According to the air path for testing the internal leakage,the gas tightness and the working life of the thermal expansion valve,design and build the testing platform to detect parameters of the thermal expansion valve automatically.(3)Design the software system of the internal leakage detection platform and the gas tightness and working life detection platform and the man-machine interface based on the touch screen,to control the platform automatically.(4)Based on the detection platform of the internal leakage and the detection platform of the gas tightness and the working life,do some experimental study on testing the internal leakage,the gas tightness and the working life of the thermal expansion valve.Analyze the change trend of the pressure and temperature of the gas path in the testing process.Verify the accuracy of the internal leakage test,air tightness test and static superheat detection and the efficiency of the working life detection.Analyze the repeatability of the testing results of two detection platforms.Evaluate the performance of the two detection platforms through various experiments.