GB318049A - Improvements in or relating to fire-extinguishing sprinkler systems and more particularly to automatic alarm apparatus therefor - Google Patents

Abstract

318,049. White, A. E., (Automatic Sprinkler Co. of America). Nov. 6, 1928. Alarms operated by flowing liquid.-In an alarm arrangement for automatic sprinkler systems, the flow of water to the alarm mechanism is controlled by a pilot valve adjustable so that false alarms due to water-hammer are prevented. and a fluid-pressurerespansive retarding device is also associated with the alarm mechanism. In the dry pipe system shown, the main water valve 18 is adjustably carried by an arm 21 which is loosely pivoted in the casing 16 at 25 in bearings having enlarged bores, the position of the pivot pin within the bores being controlled by a spring 31, so as to prevent lost motion at the pivot. A pilot valve 34, co-operating with a tubular seat member 37 which admits water to the alarm mechanism when the valve 18 opens, is so carried at the free end of the arm 21 that the latter can lift slightly, under water-hammer or the like, without lifting the valve 34, the extent of this free motion being adjustable by removing a plug and adjusting the member 37. An opening 48 in the casing 16 gives access to the pilot valve, and a pipe 47 conveying water to the alarm mechanism is screwed into an opening 46. The pipe 47 connectswith a chamber 55, Fig. 3, in a casing 56 on which is bolted a second casing 58, a pressure-responsive diaphragm 60 being clamped between the casings. When the pilot valve opens, water passes to the chamber 55, and thence, by a strainer 71 and restricted opening 72, to a chamber 66. If the pilot valve immediately re-closes, as after water-hammer, the water drains away through a still smaller opening 74 and chamber 76. If the pilot valve remains open, as when a sprinkler head has opened, most of the water from chamber 66 passes by a passage 67 to the casing 58. building up pressure above the diaphragm 60. The latter is connected by a stem 90, Fig. 1, to a valve 82 in a chamber 78 which is connected by a pipe 87 to the main water pipe 10. When the pressure in chamber 60 is sufficient to overcome that in the chamber 78, the valve 82 is opened, and water from the main is free to pass to a chamber 79 and thence by a pipe 93 to the alarm mechanism. The pipe 93 leads to a water wheel 106, Fig. 2, which drives, by means of a shaft 107, a wheel 99 carrying centrifugal elements 100 adapted to strike a gong 97. In addition to this alarm, or as an alternative, water from the pipe 93 may pass to a casing 118, Fig. 1, containing a diaphragm 119 adapted to move a switch 110 to close an electric circuit containing a bell and a lamp. A cover 69 in the casing 56 gives access to the members containing the apertures 72. 74 so that these may be replaced by members having apertures of different sizes, so as to vary the degree of retardation. The pipes 47 and 87 are provided with stop cocks, so that the alarm mechanism may be rendered inoperative without putting the sprinkler out of action.