This article covers the Two-stage Pressure Regulator Principle , Two-stage Pressure Regulator diagram, operation, advantages & disadvantages.
Two stage regulators are two single stage regulators in one that operate to reduce the pressure progressively in two stages instead of one.
Two-stage Pressure Regulator
The first stage, which is preset, reduces the pressure of the supply gas to an intermediate stage; gas at that pressure passes into the second stage.
The gas now emerges at a pressure (working pressure) set by the pressure adjusting control knob attached to the diaphragm.
Two stage regulators have two safety valves, so that if there is any excess pressure there will be no explosion.
Also Read Single-stage Pressure regulator principle - click here
A major objection to the single stage regulator is the need for frequent adjustment. If the supply pressure falls, the outlet pressure may change, necessitating adjustment.
In the two stage regulator, there is improved compensation for any drop in the supply pressure.