ABSTRACT
Gas governors are basically pressure reducing valves. Their most common role is as a constant pressure device to give a constant outlet pressure from a higher and possibly varying inlet pressure, over a range of throughputs. Low pressure governors normally handle low inlet pressures up to about 0.34 bars, and give a range of outlet pressures from about 3 to 80 mbar. High-low governors, high pressure governors for use on district governors, and zero pressure governors are increasingly being used. Zero pressure governors are used principally in pressure air injection systems such as the air blast system. They are also used in the backloaded mode with pressure divider type of ratio control system. Any increase in outlet pressure raises the diaphragm and partially closes the valve, so tending to restore the outlet pressure to zero gauge pressure. Conversely, any suction at the outlet partially opens the valve and again restores equilibrium between the atmospheric and the outlet gas pressures.
