The regulator will also maintain a steady working pressure as the cylinder pressure drops from use. Basically, regulators work by admitting the high cylinder pressure through a valve which is operated by a flexible diaphragm. By turning the regulator adjusting knob or screw in or out causes a spring in the regulator to operate the diaphragm which opens or closes a valve in the regulator. This in turn regulates the outlet pressure and flow. By turning the adjusting knob in you increase the flow and pressure, out decreases the flow and pressure.
Most regulators have two gauges.
There are two general types of regulators, single stage and two stage. Both perform the same function but the two stage regulator will supply a more constant pressure as the cylinder pressure falls by compensating for any drop in cylinder pressure better than will the single stage unit. Also, two stage regulators are usually more heavy duty in construction and will last longer in heavy duty use and require less maintenance than the single stage units. Two stage regulators can be identified by their second pressure chamber where single stage units have only one. Oxygen and Acetylene regulators connect differently to their cylinders so they can not be mixed up.