GB230966A - Improvements in or relating to fire-extinguishing dry-pipe sprinkler systems - Google Patents

Abstract

230,966. Cross, J. W., and Fawcett, J. Feb. 16, 1924. Fluid-actuated valves. - An accelerator for a dry-pipe valve system, in which the air pressure is adapted more quickly to open the differential valves, comprises two diaphragms f, g a piston valve i working in a chamber j, and an air valve k, all mounted on a spindle e held in its uppermost position by a spring e<2>. On charging the installation the air under pressure passes through flanged pipes b<3> to the accelerator chamber and, by a loosely fitting bored spindle d<1> having holes d, to a chamber b<1> above the diaphragms. The upper end of the bored spindle passes through a Muntz metal washer d<2> and enters a screwed-on thimble d<3>. When the air pressure falls, due to a sprinkler acting, the valve k, moved from its seating under the influence of the diaphragms, allows the air under pressure to escape from below the piston valve i so that it falls till its holes i<1> are in alignment with holes j<1> in the valve chamber. The air under pressure then escapes into the vessel b<2> and through pipes l<1>, l<2> actuates the differential valves and may also pass to an alarm. An atmospheric chamber h is located between the diaphragms f, g. The diaphragm g is larger than the diaphragm f to allow the air pressure to maintain the valve k against its seating in normal circumstances. An air-release valve m and a water-release valve n are fitted at the upper and lower parts of the accelerator casing respectively.