Differential Pressure Leak Detector Development And Study On The Method Of Optimization Compensation

Sealing devices are widely used in modern industrial production, andsealing performance is a key technical indicator closed the device. Therefore leakagedetection is one of the most critical means to ensure the sealing performance, whichis the guarantee of product quality, production and life safety. Common methods forleak detection are including bubble method, coating method, tracer gas leak detectionmethod, flow method, ultrasonic method and the pressure variation method etc.Wherein, the differential pressure change detection method is widely used because itssymmetry can eliminate the effects of some environmental factors. However, atpresent, the domestic differential pressure detector are difficult to match with abroadeither in the detection accuracy or the test efficiency.In this paper, through the analysis of simulation and experimental research onthe temperature of two cavity detection process, a new set of differential pressureleak detection equipment was developed, which has been optimized mainly in theonline measurement, temperature compensation, equipment portability and otheraspects. The following tasks were completed:Firstly, mathematical models of the inflation process and differential detectionprocess were found base on the gas thermodynamic theory. The gas pressure,temperature and ambient temperature effect on cavity leakage rate during thedetection process were studied by numerical simulation.Secondly, the differential pressure leak detection system experiment platformwas designed and built. System control software was developed based on LabVIEWsoftware platform, which can achieve the function of performance test, dataacquisition, data storage and so on. The temperature change of cavity and thestandard cavity by the testing process is studied experimentally.Thirdly, online automatic measurement program of vessel volume was designedaccording to gas dynamics and energy conservation. Several experiments has beenperformed to test the feasible of the scheme. And the test result shows that the errorrange remains within2.5%. Finally, a scheme of temperature compensation was designed based on theresults of theoretical and experimental, then the leakage rate detection experimentwas conducted and the repeatability and accuracy test has been evaluated. Testingresults got by calculating the relative standard deviation show that the instrumentreproducibility is within10%, which conformed to the detection equipmentrequirements. The accuracy of instrument was achieved according to relativeindication error. experiments were performed on a certain leakage rate workpiece,before temperature compensation, the relative indication error is15.34%. aftertemperature compensation,the relative indication error is2.11%. Therefore，thedetection accuracy of instrument improves significantly with temperaturecompensation.