GB173256A - Fluid-operated stop-gear for boiler pumps and the like - Google Patents

Abstract

173,256. Marks, E. C. R., (Veenschoten, V. V.). July 26, 1920. Addition to 172,355. Stop-gear.-In apparatus normally operated by the difference in pressure between two fluids, as described in the parent Specification, a modified valve is arranged to admit one fluid to both ends of the apparatus when the difference in pressure between the two fluids falls to a predetermined amount. The Figure shows the steam supply valve 12 of a boiler feed-pump operated by a piston 16, the upper end of which is connected to the feed-water pipe by pipes 25, and 19, while the lower end is connected to the steam pipe by pipes 30 and 20. The pipes 25, 19, 30, and 20 are connected to a casing 14 containing a valve 22, the upper surface of which is acted on by the feed-water pressure, while the lower surface is acted on by the steam pressure. In the event of failure of the feed-water pressure, the steam pressure raises the valve 22 and passes to the upper end of the piston 16 while a valve 27 on the spindle of the valve 22 shuts off the steam supply to the lower end of the piston 16 and opens it to exhaust through the pipe 30 and a port 28. In order to regulate the difference of pressure necessary to open the valve 23 the valve spindle may be acted on by a spring below the valve 27 or by a spring 35 above the valve 22, or by both. The tension of both springs can be regulated by means of screws. In order to facilitate the seating of the valves the valve 27 may have lost motion on the spindle. A check-valve and a valve controlled by the level of the water in the boiler are arranged in the feedwater pipe.