Patent GB-1450058-A (GB)
Title: Fire extinguishers
IPC: A62C13/70
Filed: 1972-12-11
Abstract: 1450058 Fire extinguisher MERRYWEATHER & SONS Ltd 5 Dec 1973 [11 Dec 1972] 57160/72 Heading A5A In a fire extinguisher comprising a hollow body 1 provided with outlet means for dispensing the extinguishant therefrom, the operating means for the extinguisher include a plunger 5 having an inoperative position in which it is held by engagement between projections 30 on the body closure member 4 and recesses 29 in the plunger, and an operative position to which it is rotatable, in which projections 30 and recesses 29 are disengaged and the plunger is axially movable in both directions from its axial inoperative position. Fig. 1 shows an extinguisher of the type in which water or foam is discharged by compressed gas from a cylinder, Fig. 9 a powder/ compressed gas extinguisher and Fig. 10 a chemical foam-producing extinguisher. In Fig. 1 the extinguisher body 1 is of steel and has neck opening 3 in which is received an assembly of plastic closure member 4 and plastic operating plunger 5. Closure 4 is formed with stepped bore 9, annular recess 10 surrounding 9, and passage 11 leading into passage 12 in lateral projection 13. Handle 14 is provided on the opposite side of 4 to projection 13. Cylinder 15, e.g. of compressed CO 2  is screwed to the foot of bore 9 and is closed by frangible diaphragm 17 mounted adjacent to piercing member 20 on the end of plunger shaft 21, which is slidably and rotatably received in bore 9. Shaft 21 is provided with flange 22 and seal 23 and at its outer end is screwed into bore 24 in shaft 25 of plunger knob 26. Knob 26 is formed with outer cricular flange 27 from which depend two diametrically opposite members 28 each provided with recess 29 engageable, on rotation of knob 26, with projections 30 on 4, the latter being aligned with projection 13 and handle 14 and formed with stops 31 against which members 28 abut to limit rotation of knob 26. In the inoperative position of the extinguisher the knob is positioned with projections 30 engaged in recesses 29, thus limiting axial movement of shaft 21 to the extent that piercer 20 does not touch diaphragm 17. The knob may be thus retained by a wire passing through it and member 4 and sealed at the ends. To operate the extinguisher, knob 26 is rotated through 90‹ relative to member 4 to release recesses 29 from projections 30, and to clear the lower ends of 28 from projection 13 and handle 14 so that knob 26 can be depressed to move piercer 20 against diaphragm 17. CO 2  from 15 enters body 1 via radial passages 35, 36 in in member 4 and forces water or foam out through pipe 37, passages 11, 12, flexible hose 38 and nozzle 46. When manual pressure on knob 26 is withdrawn, the knob is urged outwardly by helical spring 32 acting on the base of shaft 25 and by a gas pressure on. flange 22 to apply seal 23 to the step in bore 9 to seal off vent 39. Spring 32 also acts to move shaft 21 outwardly and away from diaphragm 17 should knob 26 be acidentally rotated. Free end 41 of handle 14 may be formed with a transparent cover over a recess in which an information label may be stored, and plastics nozzle 46 may contain an embedded magnet so that hose 38 may be normally stored coiled round the metal extinguisher. The Fig. 9 extinguisher is a modification of the Fig. 1 extinguisher for dispensing powder, compressed gas cylinder 15 being surrounded by outer tube 54 provided with apertures 56 in lower end 55. The Fig. 10 extinguisher is also a modification of Fig. 1 for discharging foam produced on admixing acid and alkaline liquids. In this embodiment the piercer and diaphragm arrangement is replaced by valve 61, 62 acting on seat 63. In each case knob shaft 25 may be provided with means preventing, after operation, inadvertent reversion to the inoperative position, e.g. members which, when free of bore 9, move outwardly to form abutments. Alternatively or in addition spring 32 may be arranged to exert a torque on knob 26 relative to member 4 to bias 26. in the direction of engagement of recesses 29 with projections 30.