What is the difference between a single-stage and a dual-stage regulator?

Single-stage regulators reduce pressure in one step to deliver pressure within a defined range. Regulators crafted in this manner will show a slight variation in delivery pressure as the cylinder pressure falls during use. Because of this, single-stage regulators are best suited for applications where a constant outlet pressure is not crucial, where an operator can supervise and readjust pressure, or where inlet pressure is steady.

Dual-stage regulators provide the same function as single-stage regulators. However, delivery pressure holds constant as cylinder pressure decreases. Increased accuracy in pressure control is maintained because the pressure reduction is performed in two steps. Dual-stage regulators are favored for applications calling for a constant outlet pressure throughout the life of a gas cylinder.