GB1307095A - Dual nozzle sprinkler heads - Google Patents

Abstract

1307095 Automatic fire fighting systems FACTORY MUTUAL RESEARCH CORP 20 Oct 1970 49811/70 Heading ASA A method of fire-fighting comprises automatically discharging two extinguishant streams, one of relatively fine and the other of relatively coarse droplets. The method may be embodied in a fixed automatic sprinkler system involving either dual-nozzle sprinkler heads or a conventional single-nozzle head arrangement in which the fine and coarse sprinklers are interspersed. The nozzles are thermally actuated independently or simultaneously as required. Preferably the fine droplets are less than 1 mm in diameter, and the coarse greater than 2 mm. Figs. 3-5 illustrate alternative dual-nozzle sprinkler heads. In Fig. 3 the fine nozzle is jet nozzle 10 normally closed by quartz bulb 16, and the coarse nozzle is pendant nozzle 17 formed with discharge opening 18 and serrated distributor plate 20 and normally closed by cap 26 co-operating with link lever 22 and fuse 24. Both nozzles communicate with T-fitting 12 whose inlet is connected to water supply pipe 14, and a restricted orifice is situated upstream of outlet 18 to reduce the velocity and thus the pressure of the extinguishant issued from coarse nozzle 17. Bulb 16 may be adapted to release at a lower temperature than fuse 24. In Fig. 4 the water supply line 30 is horizontal, and X-type fitting 32 communicates with pendant coarse nozzle 17 and radial spray or fog nozzle 38 equipped with link lever fuse release 40. In Fig. 5 both nozzles are actuated by release 42. Valve 44 having serrated skirt 46 and stem 48 is seated against supply line 14. On actuation, the valve moves down so that skirt 46 rests on orifice plate 28, thereby opening both nozzles. Figs. 6-7 (not shown) illustrate an arrangement of separate interspersed fine and coarse sprinkler heads.