Specialized Gas Equipment for Speciality Gases
Often a Specialty Gas representative is challenged by an end user regarding the appropriate specialty gas pressure regulators, manifolds valves, etc. that should be used with the specialty gases they are purchasing. I can assure you that after 27 years in the gas industry that there is an immense difference in the quality of industrial gas equipment and specialty gas equipment.
An industrial gas regulator will have a leak integrity of “bubble tight”, sport a couple of large neoprene diaphragms, and be made of a forged brass body. A well constructed specialty gas regulator on the other hand will have a leak integrity designed to pass an inboard helium leak-rate of 1 x 10 to the minus 9, sport dual stainless steel diaphragms, and be made of a machine polished brass body. While this may all sound somewhat technical, what it means to an end user is that the ultra high purity (UHP) gas in the cylinder that was purchased will be delivered to his / her application with the same integrity as it exists in the cylinder.
Using UHP Helium as an example, there should be less than 2 ppm of Moisture, less than 1 ppm Oxygen and less than 0.5 ppm Total Hydrocarbons in this gas to meet the criteria of a Grade 5.0 gas. If we utilize an industrial regulator with this gas, we will deliver atmospheric Oxygen and Moisture to the gas stream due to the low leak integrity and we will deliver Hydrocarbons to the gas stream via the large neoprene diaphragms. So we deliver the same contaminants to the gas stream (in abundance) that the gas company removed from the gas to make it Ultra High Purity in the first place.
The investment in the UHP gas has been lost and the application that is expecting to receive a UHP gas will receive a heavily contaminated gas costing additional dollars in failed analysis and repeat processes. If you invest in UHP Specialty Gases, nurture your investment by using the appropriate gas delivery equipment. Also, never swap regulator use from one gas to another because serious cross contamination can occur as well as significant safety issues.