GB778318A - Improvements in or relating to temperature responsive signalling device - Google Patents

Abstract

778,318. Temperature alarms; warning horns. FYR-LARM CO., Inc. Jan. 11, 1955, No. 814/55. Class 13 and 118 (1). A reed horn 30, Fig. 2, may be sounded by pressure fluid escaping from a cylinder 10 if the ambient temperature rises to a predetermined degree, as on fire condition, to melt a readily releasable fusible plug 20, a safety valve 34 releasing fluid from the chamber 26 if the pressure therein rises above say 2 lb. per sq. inch. A metal plug 12 having an expansion chamber 18 opening to the horn is provided with a passage 15 leading to the. interior of the cylinder, and a metering hole 16 formed by an annular shoulder 16a and normally closed by the fusible metal plug 20. A skirt 21 with vent holes 22 surrounds the cylinder 10 to direct air around the plug 12. In a modification, Fig. 7, the safety valve comprising a movable reed plate 29<SP>1</SP> and a spring 37 is at the other end of the horn, and the protecting screen 31 may be replaced by a thin disc of metal 39 normally held over the end of the horn by a fusible ring 40, which ring melts before the plug 20 and allows the disc to fall off.