Mason patent steam pressure reducing valve, 1886

Mason patent 1886, standard steam pressure reducing valve for 1" diam. steam pipe, in quarter section

This is an example of the steam pressure reducing valve patented by the Mason Regulator Co., U.S.A., in 1886. In it the main valve is not operated directly by the steam acting on a diaphragm connected with it, as in the earlier reducing valves, but the diaphragm moves a small regulator that admits high- pressure steam behind a piston which then lifts the valve.