High Pressure Leak Detection System Based On External Pressure Differential Pressure Method

As the main quality performance parameters of sealing products airtightness more and more get the attention of the sealing productsmanufacturers. Air tightness test plays a very important role to guarantee thequality performance and the use security of sealing products. With thecontinuous development of science and technology level, the traditional waterdetection method in industry is used to gradually replace by dry air tightnessdetection method. Dry air tightness test methods mainly include direct pressuredrop method and internal pressure differential method. The two methods areall used to detect the internal pressure (differential pressure) of tested pieces tocalculate the leakage flow rate, so detection accuracy easily affected by thechange of external environment. Especially about the detection of highpressure vessel, the influence of the pneumatic cut-off valve and leakage ofgas pipeline for precision is obvious， sometime it even leads to error fordetection system. In view of the defects existing within the direct pressure anddifferential pressure method, this paper proposes an air tightness test methodbased on differential external pressure method, and the theoretical andexperimental research of this air tightness test method has been conducted.This article firstly expounds the basic principle of air tightness testmethod based on differential external pressure method. Secondly, themathematical model about the filling process and testing process of this testsystem is established, and the MATLAB software is used to simulate themathematical model. Through the analysis of simulation results, the mainfactors affecting the test precision are summarized, and theoreticallycalculation formula of leakage rate of this test method is deduced. Thirdlybased on the testing method, a set of high-pressure gas tightness test system isdesigned, and the system hardware and software design process are brieflyintroduced. Finally, the test system is employed to make certain experiments,and the experiments presented to illustrate the validity and feasibility of this test method.