GB1395174A - Fire protection system - Google Patents

Abstract

1395174 Sprinkler systems FACTORY MUTUAL RESEARCH CORP 27 July 1972 [8 Sept 1971] 35142/72 Heading ASA A fixed fire protection system has at least one extinguishant discharge head and means for connecting the head(s) to a source of extinguishant wherein the or each head comprises a body member 12 having an inlet for a source of extinguishant under pressure, an outlet 16 for discharging the extinguishant, a plug means 24 disposed in the body member for preventing the discharge of extinguishant from the outlet, and detent means for retaining the plug relative to the body member to close the outlet and constrained to release the plug from the body member to open the outlet in response to a pressure acting on the plug which is greater than a predetermined extinguishant pressure in the body member to permit the discharge of extinguishant from the outlet. The detent means comprises at least one spring-loaded element which may have means for adjusting the load on the element to change the value of the predetermined extinguishant pressure. The plug means may have a rod 22 and a head portion; the spring-loaded element may be a ball 60 having a portion extending into groove 69 formed in the rod 22; and the adjusting means may comprise sleeve 56 mounted in the body member in a concentric relationship with and adapted to receive an end portion of the rod, the sleeve having a bore 62 formed in the wall thereof for receiving ball 60 and spring 64 for the ball, the bore being aligned with the groove when the detent means retains the plug relative to the body member. A further ball 66 slidably supported in bore 62 and engaging spring 64, and a cup 70 concentrically disposed relative to sleeve 56 and in threaded engagement therewith, an inner wall of cup 70 having a tapered surface 74 which engages ball 66, whereby rotation of the cup changes the position of ball 66 in the bore and thus changes the resulting compression of the spring and the resulting load on ball 60. A plurality of the balls 60 and associated springs 64 and further balls 66 may be supported in respective bores in the sleeve, all the balls 60 engaging rod 22, whereby rotation of cup 70 effects a uniform change in the load on balls 60. As shown, latching means for retaining the plug in the body member comprises a rod 32 extending into tapered hole 36 in rod 22. A fusible member 44, responsive to a predetermined temperature in the vicinity of the discharge head activates spring 48 to retract rod 32 to release the plug. The plug is forced downwardly in proportion to the extinguishant pressure providing the pressure exceeds the predetermined locking force of balls 60, thus limiting the number of nozzles activated. The discharge is given a swirling motion by spiral vanes 18a, 18b.