Research Of Volume-Compensation Leak Detector And The Feature Of Charging And Discharging Procession

Tightness is an important standard of judging the quality and performance of a sealing device, it determines the quality of the products. In the industries of car, gas appliances, and aviation, leakage detection is the essential link in the production processing. It can not only reduce the intensity of workers’work, but also can improve the quality of the product and the efficiency to research an automatic leak detector of high precision and efficiency, especially in mass production.The principle of air-pressure method of leak detection is introduced in this paper, and proposed the volume-compensation method of leak detection base on the differential-pressure method. This thesis main work and research results are as follows:1. This thesis has introduced the research status and the development trends of leak detection technology, and analysis the principle of various methods of leak detection.2. In order to study the effect of temperature on leak detection, I researched the system on thermodynamic, and established a mathematical model of the leak detection, then simulating in MATLAB/SIMULINK. Through the simulation, we can clearly understand the procession of temperature changing, and know how parameters influence the temperature.3A leak detector which is based on the volume-compensation method is designed. The system is designed into symmetrical structure in order to reduce the effect of temperature. And an electrical-pneumatic proportional valve is used to control the charging or discharging mode, time and pressure of the leak detector in the place of air intake. It has adopted a high-precision differential-pressure sensor of Honeywell company and a data acquisition card of16-bit conversion accuracy in order to improve the accuracy of leakage detection.4. The leak detector is controlled by a computer, a program which can display the data and control the leak detector was wrote by the VC++/MFC in the VS2005software. 5. The curves of changing temperature were drew on different charging and discharging parameters through the experiments. And then find the best charging and discharging time of different pressure. The volume-compensation method is proved to be rational by the experiment of testing the leakage rate of measured container on different pressure.