Research On Control System For Alternative Pressure Test

The air conditioner components in the cars or domestic coolers are all used under alternative pressure and hot circumstance,such as compressors,condensers,evaporators,accumulators,dryers,tubes and other similar parts.The reach about alternative pressure is to detect the fatigue limits of parts that working under the imitation circumstance,such as the alternative pressure of circle liquid,cabinet temperature,the cabinet humidity and circle liquid temperature.Not only the types of alternative pressure curves can be imitated,such as sine wave,triangle wave, ladder-shaped wave and wantonly irregular pressure waves,but also the peak of alternative pressure,the valley of alternative pressure,frequency of pressure curves and working temperature can be imitated.The alternative pressure test is normally carried out on the closed system.The actual precision is affected by the type of closed system.It is important to pay attention to the volume and structure of the closed system.The character of circle liquid is anther important impact,such as modulus of elastic and flow character.This article is to research a compute control system about alternative pressure.The limit control pressure is 3∽13 MPa,the limit control frequency is 0∽1 Hz and the limit control temperature is 60℃∽150℃.It is suitable to be used for high pressure,high frequency and high temperature test,such as the coolers that use CO₂ for circle liquid.This article describes the based types of alternative pressure test,the working theory of different type test and the structure of each type.It point out the strong and weak points of different test based on the introducing about servo hydraulic control system,the electric control system and experiment researches.It is useful to improve the inland research about alternative pressure tests.The best match is the key of hydraulic control system.The modulus of elastic,the flow characters of circle liquid,the air capacity of circle liquid and the structure of tubes are especially important.The reliability design is the most important impact of electric control system.The suitable structure of electric control system and the high quality of each component are due necessary.The variable coefficient PID control method and high speed communication technology are useful to improve the control precision.This article provides a complete design and control method according to the theory calculate and analyse of experiments.It is useful to improve the research about alternative pressure test.