What is helium leak detection?
Helium leak detection refers to the process of identifying leaks in an enclosed or sealed system using helium as a tracer gas. Helium is an ideal choice of tracer gas to find leaks because it is non-toxic, non-flammable, non-condensable, and its presence in the atmosphere is limited to 5ppm. Helium can pass easily through leaks because of its small atomic size. Additionally, helium is safe to use because it does not react with materials of parts being tested.
Overview of sniffer probe leak detection
Sniffer leak testing is a common tracer gas leak detection method that uses a sniffer probe to detect the presence of tracer gas and identify an area that is leaking. Under sniffer probe helium leak detection, helium is used as a tracer gas in combination with instrumentation to detect the presence of helium and more precisely an increase in helium due to the leaking part.
The prime objective behind conducting a sniffer probe leak detection test is to locate leaks in parts or systems so that they can be identified and repaired. The part or system is first pressurized with the tracer gas and then systematically scanned with a sniffer probe so as to detect possible leaks. Sniffer probe leak detection cannot be considered as a quantitative leak detection technique because the test results may vary depending on skill of the operator and the technique used. However, with the use of calibrated instruments, calibrated leak standards, and well-trained operators, quantitative results may be achieved. Sniffer leak testing is considered as an economical leak detection method that involves relatively low tool cost investment depending on the tracer gas used. Although sniffer probe leak testing is very effective in locating micro leaks, it may not be an ideal choice in high volume production environment.
How does sniffer probe leak detection work?
Sniffer probe leak testing begins by first filling the test object with tracer gas. The pressure inside the test object is increased to a pre-determined rate in order to create a differential in pressure. The outside of the test object is scanned using a sniffer probe that is connected to a leak detector. Because of the innate properties of helium, it readily penetrates through leaks and is sucked into the sniffer probe. The leak rate meter shows a display of the signal. On reaching maximum leak rate display, leak is located. Although the sniffer probe leak detection technique is very sensitive, its accuracy can be affected due to the amount of helium present in the atmosphere.
Advantages of Sniffer Probe leak detection
- Sniffer probe is very effective in locating minute leaks.
- Does not require expensive fixtures or test chambers and can be employed at low cost.
- Useful in testing small parts as well as complex systems.
- Higher test sensitivity can be achieved by increasing tracer gas pressure.
- Capable of detecting leaks in the range of 1.6x10-1 to 1x10-5 scc/s.
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