Vacuum Technology

Leak Testing Applications

There are several leak testing methods. Below of are a list of possible leak testing methods for your application.

HARD VACUUM TEST

This method allows for leak detection down to 1 x 10-9 atmcc/sec. Leaks in the test part can be measured inside-out or outside-in.

  • For inside-out leak detection, the test part is either filled and sealed with helium inside, bombed with helium after it is sealed, or temporarily pressurized with helium during the test. The part is placed in a vacuum chamber and the chamber is evacuated.
  • For outside-in leak detection, the test part is evacuated and helium is sprayed on the outside of the part. The helium leaking from the part is sampled through the vacuum line by the helium mass spectrometer leak detector.
DIFFERENTIAL VACUUM TEST This method is similar to the hard vacuum test. However, the vacuum system is designed to control the differential pressure across the part under test. This is achieved by evacuating both the vacuum chamber and the test part to a desired vacuum level. This test is ideal for leak testing components that cannot be safely exposed to full vacuum such as automobile fuel tanks.
ONE STEP HARD VACUUM TEST This method achieves very fast cycle times for small test parts. With a properly designed vacuum circuit and parts smaller than 10 cc, cycle times as low as 3 seconds can be reached.
ATMOSPHERIC SNIFFING TEST This method allows for leak detection down to 1 x 10-6 atmcc/sec. The test part is pressurized with helium and leakage out of the part is measured using a sniffer probe which is attached to the helium mass spectrometer leak detector. This technique can utilize any number of sniffer probes strategically located to measure leak rate and locate leaks.
ATMOSPHERIC ACCUMULATION TEST This method is similar to the sniffing test. However, the helium escaping the part is allowed to accumulate in a chamber or enclosure that surrounds the part at atmospheric pressure. The accumulated helium is mixed and sampled by the helium leak detector. The accumulation test has the advantage that it does not require a vacuum chamber or vacuum pumps. It also tests for global part leakage unlike the sniffing method. This test method is capable of detecting leaks down to 1 x 10-5 atmcc/sec depending on part size and required cycle time.
MULTI-GAS LEAK TESTING There are times when helium is not the ideal tracer gas for a particular leak testing application. The test part may already have another gas present, filling with helium may be too costly, not possible, or be harmful to the product. Under these conditions we implement many of the traditional helium leak testing methods utilizing gas sensors capable of measuring other gases. Sensitivities of this method are as low as 1 x 10-7 atmcc/sec in production environments. Some common test gases are R134a, SF6, Argon, Hydrogen, Nitrous Oxide, CO2.
AIR LEAK TESTING Air leak testing involves a family of several test methods including pressure decay and mass flow using air as the test gas. These techniques are capable of measuring leakage outside-in or inside-out under vacuum or pressure conditions. Leakage is measured by creating a pressure differential across the test part and measuring the pressure rise or drop using a pressure transducer or the actual flow using a mass flow meter. This method is capable of detecting leaks down to 0.01 atmcc/sec depending on part size, part construction, and cycle time.
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Vacuum Technology

APPLICATIONS