Testing with a tracer gas is one of the most effective methods for detecting and measuring leaks.
Helium is the most commonly used tracer gas for leak testing, because it is the lightest of the inert gases and mass spectrometers are extremely sensitive to trace amounts. However, mass spectrometers can be delicate and expensive to maintain. The instrument’s pumps must be regularly checked and serviced. In addition, the helium itself can cause problems. Helium is expensive and highly viscous. If it spills, it can be difficult to clear from the testing equipment. It also tends to cling to surfaces.
More recently, hydrogen has emerged as an alternative to helium. The lightest and least viscous of all gases, hydrogen spreads quickly throughout the test object. It readily penetrates the smallest leak, and it vents away much easier than other tracer gases. Hydrogen is environmentally friendly and much less expensive than helium.
In the right concentration, hydrogen can be safely used for leak testing. According to the ISO 10156 standard, any hydrogen-nitrogen mixture containing less than 5.7 percent hydrogen is nonflammable.
Although hydrogen-based testing is not as sensitive as helium-based testing, the equipment is substantially less expensive. Equipped with microelectronic sensors, hydrogen detectors have a high sensitivity and selectivity to hydrogen.
One of the newest hydrogen leak testing instruments on the market is the H6000 from ATEQ Corp. The compact instrument is available in two versions. A fixed version is designed to be installed in automated test systems or standalone workstations. A portable version is designed for manual inspection of components with a sniffer probe at the end of an assembly line.
The device uses a mixture of 5 percent hydrogen and 95 percent nitrogen, which is available from most gas suppliers.
The instrument can detect leaks as small as 0.05 standard cubic centimeter per minute—about 80 times smaller than what is typically possible with an air-based test.
Features include programmable suction control, IP 54 protection, visual and audible pass-fail signals, and the ability to store 128 leak test programs. The portable unit is powered by a lithium battery and can run eight hours on a charge.
For more information on leak test instruments, click https://atequsa.com/ or visit the company’s booth at The ASSEMBLY Show South, which will be held April 30-May 2, 2024, at the Music City Center in Nashville, TN.
Besides test and inspection technology, you’ll find some 150 suppliers of automation, robotics, parts feeders, fastening tools and other assembly technologies. For more information, visit www.assemblyshowsouth.com.
