How to Chose a Proper Gas Pressure Regulator (Governor)?

Many factors should be considered when choosing a proper gas pressure regulator(gas controller).

From the angle of gas type:

1.General Gas Use. For general use, regulators of brass construction with elastomeric diaphragms will give good service in noncorrosive service where slight contamination or diffusion from an elastomeric diaphragm is not important. Brass regulators with stainless steel diaphragms prevent air diffusion and adsorption of gases on the diaphragm. This is particularly important with low concentration mixtures of hydrocarbons in which the trace component may be adsorbed on the elastomeric diaphragm.

The gas regulator must be constructed using materials suited to the application. Industrial general purpose regulators are often constructed with either Buna-N or Neoprene diaphragms. Regulators with Buna-N or Neoprene diaphragms are not suitable for GC analysis that can be affected by the diffusion of atmospheric oxygen through the elastomer diaphragm or the outgassing of monomers and dimers from the elastomer. In fact, laboratories that perform temperature programmed analysis are faced with excessive baseline drift and large unresolved peaks due to this diffusion and outgassing.

 High-Purity Gas Service. 
The ideal construction for high-purity gas service is a gas regulator that has a stainless steel diaphragm. Such regulators are not contaminating and assure satisfactory use for all applications of noncorrosive and mildly corrosive gases. Regulators for corrosive gases must be selected from those recommended with each gas listing.

A gas regulator equipped with a stainless steel diaphragm has several advantages over the elastomeric type. It does not outgas organic materials and it also prevents the diffusion of atmospheric oxygen into the carrier gas. Both Buna-N and Neoprene diaphragms are permeable to oxygen. The chemical potential of oxygen between the carrier gas and the atmosphere provides sufficient driving force for oxygen to intrude the carrier gas through a permeable diaphragm.