Leak Detection Systems
Leak detection systems are installations for testing products, either manually, semi- or fully automated, if they fulfill reasonable leak rates to guarantee their functionality over the lifetime or to fulfill regulatory obligations. For the automotive mobility market, the range of specimen includes safety, drivetrain or fuel system parts, like airbag ignitor caps, torque converters or fuel pumps, and much more. With the rise of the e-mobility market even more applications must be covered, e.g. assembled battery packs or fuel cell stacks or their respective housings. These specimens are made of a broad range of materials and will be filled with different kind of media like conventional fuel, liquid or gaseous hydrogen, cooling liquids or air, respectively. Therefore, the range of leak sizes or leak rates to be detected will vary strongly depending on the final application. Pfeiffer Vacuum can supply all components needed for thoroughly set-up leak detection systems based on the tracer gases He, forming gas or air.
- Short measurement times
- Long maintenance intervals
- High reliability
- High reproducibility
How does it work?
For the unit under test (UUT) a reasonable leak rate has to be defined and the correct measurement direction and methodology must be chosen, i.e. the specimen or the surrounding chamber/accumulation hull will be filled with a defined pressure of the selected tracer gas. The latter must be chosen carefully as temperature variances of the UUT itself or of the surrounding atmosphere can strongly influence the results if air as a test medium is chosen. Further, depending on the specimen properties not every possible testing pressure can be applied without damaging the product. This is mentioned here as the testing pressure influences directly the magnitude of the defined leak rate or the required measurement time. Finally, the specimen can be tested, and the leak detector will state whether the specimen is leak tight or not.
Vacuum and leak detection requirements
Vacuum is not necessary for all methods, for example micro-flow or bubble test measurement depict methods based solely on air under ambient atmosphere. However, air-based methods do reach limitations or difficulties if leakage rates smaller than 10-5 mbar*l/s have to be detected. For even higher leakage rate requirements integral vacuum methods can be used, including the air-based mass extraction methods. Besides this, for many leak detection processes within in the automotive industry very short testing times are required, down to some seconds, to reach pressures in the range of 10-2 to 10-3 hPa. This is often necessary to reduce the background signal to a reasonable level.
Pfeiffer Vacuum offers a complete portfolio for leakage detection systems with vacuum pumps, e.g. rotary vane pumps of HenaLine or the universal HiLobe Roots pump for high flexibility, modular leakage detectors for He or H2 detection (ASI 35) or Air based (E-PDQ) as well as other vacuum components. Furthermore, a HiPace turbopump can be utilized to shorten either the pump down or measurement time drastically.