With rising helium costs and no slowdown in sight, many users of helium leak detection equipment are looking for ways to keep costs in control. Additionally, some gas suppliers are asking customers to implement helium consumption reduction plans, even while helium usage may be rising due to growth in production. Alternate tracer gases or test methods are not available for many applications. Thus, the option of eliminating helium is often not practical. The opportunities to reduce helium consumption can be reduced to the following five strategies.
- Reducing helium waste from leaks and improper installation
- Reducing helium waste due to poor equipment design
- Reducing helium waste from unused helium left over in gas storage bottles
- Reducing helium consumption through dilution of helium gas
- Reclaiming used helium for re-use
LEAK TESTING YOUR HELIUM SUPPLY
Simply ensuring that there are no leaks in the helium supply piping is a good place to start. Leak surveys should be conducted from the helium supply bottle all the way to the point where the device under test is charged with helium. Additionally, all hoses and piping should be designed for helium use. Because helium is a small gas molecule, it permeates materials much more readily than most other gasses. Rubber or plastic hoses are normally not suitable for helium supply manifolds, particularly when used at higher gas pressures.
CHECK FOR PROPER LEAK MANIFOLD INSTALLATION
Poor design of helium charge manifolds on production leak testing equipment can waste significant amounts of helium. In some cases, the volume of helium wasted due to poor manifold design is greater than the amount of helium actually used inside the part under test. Piping diameters and lengths should be minimized and the placement of valves should be optimized to reduce helium consumption for each test cycle.
REMOVE ALL HELIUM FROM BOTTLES
Many users purchase helium either in standard, high pressure gas storage bottles or in packs or pallets of bottles. Typically, bottle pressures from the gas suppliers are in the range of 2,500 to 3,000 psi. Gas regulators are used to reduce the pressure to the desired value for the test. If, for example, an application requires the part under test to be filled to 300 psi, then once the supply bottle pressure reaches near 300 psi remaining it is no longer usable for the application. If returned to the gas supplier in exchange for a new bottle, the supplier will not give any credit for the remaining helium in the bottle. In this example, the user would be wasting approximately 10% of the gas. Two strategies can be implemented to minimize this waste. First, if a user has more than one application where helium is used he might transfer partially depleted bottles to applications that require lower pressures. For example, an application that requires spraying of helium for leak testing could use bottles that have depleted to low pressures because spraying helium can be done with very low helium bottle pressures. Second, a pneumatically operated gas booster can be used between the gas bottle and the leak testing system to boost gas to the desired test pressure. These gas boosters, normally driven by compressed air, are easy to implement. Using our example above, a gas booster capable of a 10:1 pressure ratio could boost the gas from 30 to 300 psi. This would significantly reduce waste from approximately 10% to 1%.
We will address the final two strategies for reducing helium consumption in our next article.