Leak Detection Methods vtechonline（vtechonline泄漏检测方法）.pdfVIP

Leak Detection Methods: A Comparative Study of Technologies and Techniques Short version Table of Contents 1 Introduction 3 2 Leak testing methods 3 2.1 Water immersion bubble test method 4 2.2 Soap solution bubble test 6 2.3 Pressure decay test 6 2.4 Vacuum decay test or Pressure rise test 8 2.5 Tracer gas leak testing 9 2.5.1 Sniffing 10 2.5.2 Accumulation leak testing 10 2.5.3 Vacuum chamber inside-out leak testing 11 2.5.4 Outside-in leak testing 11 2.6 Applications 12 2.6.1 Halogen leak detectors 12 2.6.2 Inside-out helium sniffer detectors 13 2.6.3 Outside-in helium spraying 14 2.6.4 Outside-in helium leak testing 15 2.6.5 Inside-out helium vacuum chamber leak testing 16 2.6.6 Inside-out hydrogen sniffer detectors 17 3 How to Choose the Test Method 18 4 Conclusion 20 1 Introduction In the refrigeration industry, components and systems must be leak tested to ensure that refrigerant leakages are below specified limits. The three basic functions of leak testing are 1) determining if there is leakage or not (detection), 2) measurement of leak rate and 3) leakage location. There are many methods and types of test equipment for solving these problems, but unfortunately there is no single technique that fits every situation. Each test method is suitable only for a specific leak rate or for fixed forms and technologies. In most instances where leak detection is used, explicit leak rate measurement is not required, but the system must be able to recognize if the leak rate is above or below a specified level. This reference limit depends on the maximum acceptable le