US 3259194 A
Description (OCR text may contain errors)
July 5, 1966 P. M cRossAN 3,259,194
LIGHT-WEIGHT PORTABLE FIRE EXTINGUISHERS Filed April 20, 1964 2 Sheets-Sheet 1 W w (g INVENTOR 'PA-TR m I: Mc Qeo s s 6! BY JK A TTOE'NEYS y 5, 1956 P. MGCROSSAN 3,259,194
LIGHT-WEIGHT PORTABLE FIRE EXTINGUISHERS Filed April 20, 1964 2 Sheets-Sheet 3 2; A /M W A T TORNEYS United States Patent 3,259,194 LIGHT-WEIGHT PORTABLE FIRE EXTINGUISHERS Patrick McCrossan, Haywards Heath, Sussex, England, assignor to Stoppafire Limited, Manchester, England Filed Apr. 20, 1964, Ser. No. 360,995 8 Claims. (Cl. 169-31) The present invention relates to fire extinguishers, and particularly, although not exclusively, to the portable kind known as water type (gas pressure) extinguishers. A general description of extinguishers of this kind will be found in British Standards Institute specification No. 1,382 (1948).
The invention is suitable also for use with other types of extinguisher such as those using carbon tetrachloride, or soda-acid extinguishers and foam extinguishers.
In water (gas pressure) extinguishers a high pressure gas cartridge is screwed into the head of the container which is filled to a required level with Water. The extinguisher is operated by striking a knob. This breaks or pierces the gas cartridge and the gas is released into the extinguisher which then discharges a jet of water to a distance generally of about 40 ft.
Due to the high internal pressure the container has to withstand (normally up to 500 psi), known containers have been constructed of metal, either copper or specially treated steel. The ancillary parts such as the cap and hose fitment are also normally constructed of metal. This adds considerably to the weight of the extinguisher and also introduces the risk of corrosion.
According to the present invention there is provided a method of making a container for a fire extinguisher comprising the steps of producing, by moulding a thermosetti-ng resin, two cups one of which is formed with a pair of apertures at or near its otherwise closed end, sealing into the apertures a striker mechanism and a hose fitment respectively, loading the apertured cup with fire extinguishing accessory apparatus such as a gas cartridge and sealing the cups together at their open ends.
According to a further feature of the invention, there is provided a fire-extinguisher container comprising two cups made of thermosetting resin sealed together at their open ends, one cup being formed with two spaced apertures at or near its otherwise closed end, a striker mechanism and a hose fitment being sealably fitted in the two apertures respectively.
The material used for the container must have a high tensile strength. It is therefore preferred not to use thermoplastic resins which generally retain some thermal stress after moulding and are liable to soften and lose shape at above average atmospheric temperatures. Many known types of thermosetting resin are now known which would be suitable when reinforced, as will be apparent to those skilled in the moulding of plastics. Particularly suitable materials are the group known as Dough Moulding Compounds (D.M.C.) which comprise a base of polyester or epoxide resin in which is dispersed a high content of filler or reinforcement material, which in the preferred compounds includes glass fibre of various lengths.
Such compounds are suitably moulded by compression. A male tool is brought down upon a female mould containing the D.M.C. (with the addition if necessary of a catalyst or hardener) in suitable quantity and the viscous material is forced to fill the space in between and allowed to set.
An example of a suitable D.M.C. compound is the product sold under the registered trade mark Rockite K-50l, which is a glass fibre rein-forced polyester resin. This has a specified tensile strength of 7,000-10,000 p.s.i.
3,259,194 Patented July 5, 1966 ice It has also other propetries of particular advantage in the present invention, namely:
(1) Good impact strength over a wide temperature range.
(2) Flexural and tensile strengths which do not vary appreciably with temperature.
(3) Ability to withstand exposure without too high a degree of ageing. Y
(4) Low water absonption.
(5) High thermal stability.
It will be appreciated however, that many other materials having similar properties are now commercially available, in particular they are common to nearly all compounds of the D.M.C. group. Preferred reinforced synthetic resin compounds should have a tensile strength of over 5,000 p.s.i.
A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying diagrammatic drawings, in which:
FIG. 1 is a longitudinal cross-section through a water gas pressure) fire extinguisher of the invention, including a hose connection, and
FIG. 2 is a view partly in cross-section of the combined hose and connector and nozzle holder on a larger scale.
The illustrated fire extinguisher container 1 is moulded in two parts, each Otf cup-like shape, namely an upper cup 2, and a lower cup 3, both being formed from Rockite K5 01. The cups are formed with male and female screw threads, respectively, at their open ends and the thickness of the walls is suitably increased to take these threads. Preferably an industrial adhesive is applied to the threads before the two cups are joined so that a verystrong sealed joint is formed. The formation of the container in two parts as illustrated in FIG. 1 makes the moulding operation much easier and also aids the fitting of the internal accessory parts which are preferably fitted before the two cups are joined. The completed container 1 has a slight barrel shape which adds to its strength and which also allows easy access to the interiors of the two cups 2 and 3 before they are joined.
The upper container cup 2 is moulded with an aperture in a screw-threaded neck 4 to hold a screw cap 5. The screw cap 5 is also advantageously moulded from synthetic resin material and D.M.C. is preferred. The screw cap is formed with a bore 6 to hold a metal striker mechanism comprising a rod 7 which is fitted with a knob 8 of synthetic resin material. D.M.C. is again suitable, or nylon. The striker rod has a pointed lower end and is adapted to pierce a gas cartridge (not shown) in conventional manner when the knob 8 is struck. The protruding part of the striker rod 7 and the knob 8 are covered when not in use by a protective cap 9 which is suitably moulded from polyethylene of medium density.
The upper container cup 2 is also formed with an apertured thickened shoulder portion 10 to hold a mounting ring 11 for a hose fitment indicated generally at 15. The mounting ring 11 is shown moulded into the shoulder portion 10. It is itself preferably moulded from D.M.C. and may be formed integrally with the upper container cup 2. Alternatively it may take the form of an externally threaded tube retained upon the container cup 2 by nuts and washers, the container cup 2 being moulded with a flat, thickened portion to provide an air tight seal.
A tube 12, preferably of polyethylene, extends inside the container from the mounting ring 11 to a point near the bottom of the container and is provided at its lower end with a filter rose 13. The tube 12 is held in place on the mounting ring 11 by means of an inner sleeve 14.
A hose stem 16 is joined to the mounting ring 11 from the outside. The stem 16 has one end threaded both internally and externally. This end is screwed on to a portion of the inner sleeve 14 which protrudes through the mounting ring 11, a washer 17 being provided to form a good seal. A retaining nut 18 is threaded on the outside of the stem 16.
The other end of the hose fitting 15, i.e. the end remote from the container 1, is formed with a union joint 19 (FIG. 2). The end of the union joint containing the bore for the fire-extinguishing liquid is formed in suitable manner as illustrated to retain a low density polythene hose 20, a hose connector 21 being provided to hold the hose 20 firmly in position. The other end of the hose is provided with a nozzle 22 which for convenience is held in a socket 23 at the back of the union joint 19, so that it is protected from being clogged with dirt or damaged. The hose may conveniently be wound around the extinguisher.
The Whole of the hose fitting, including the stem 16, union joint 19 and hose connector 21, is preferably moulded from D.M.C. These parts are not required to be of such high tensile strength as the container, but they must have a high impact strength so as to be resistant to wear and tear over extended periods. The hose nozzle 22 is preferably moulded in medium density polyethylene. The container may have a capacity for convenient use of about two gallons.
Portable fire extinguishers according to the invention, such as the one illustrated, are very much lighter than metal extinguishers in current use, and consequently may be handled much more quickly. This adds greatly to their fire-fighting efificiency, and enables small models to be used by people of slight strength such as school children.
What we claim is:
1. A container for a portable fire extinguisher comprising tWo cups moulded from thermosetting resin, one of which cups is formed with a pair of apertures at its otherwise closed end, a striker mechanism sealed into one of said apertures and a hose fitting sealed into the other of said apertures, said fitting including a combined hose connector and nozzle retaining socket, and means sealing the cups together releasably at their open ends.
2. A container for a portable fire extinguisher comprising two cups made of thermosetting resin reinforced with glass fibers and removably sealed together at their open ends, one cup being formed with two spaced apertures at its otherwise closed end, a striker mechanism and a stem fitting being sealably fitted into the two apertures respectively, said stern fitting terminating in a joint unit.
carrying a hose connector and a nozzle holding socket, a hose having a coupling at one end, a nozzle at the other end and means securing said coupling end of the hose to the connector and said nozzle and temporarily in said nozzle holding socket.
3. A container for a portable fire extinguisher adapted to receive a high pressure gas cartridge and wherein the container must withstand high internal pressure up to approximately 500 p.s.i. comprising two molded cups each formed of reinforced thermosetting resin of high tensile strength, said two cups being interconnected with one another by male and female threads formed on the respective cups at the open ends thereof, said two cups when in assembled relationship defining a generally barrel-shaped outer configuration for the container with its maximum dimension at an intermediate portion of the container adjacent said threaded ends of the cups, one of said cups having a generally dome-shaped closed end and defining a strengthened bottom for the container, the other of said cups including a heavy shoulder portion spaced a substantial distance from the threads formed thereon, said shoulder portion joining with a relatively narrow neck having an open end, a cap closing off the open end of said neck, a striker mechanism movably supported by said cap and being adapted to reach a vulnerable part of a high pressure gas cartridge supported by the container, said shoulder having a recess formed therein, a mounting ring snugly disposed within said recess and sealed with respect to said container, said ring having a bore formed therethrough, and a tubular member extending through the bore in said mounting ring and sealed with respect thereto for discharging liquid from the interior of said container outwardly of said tubular member.
4. Apparatus as defined in claim 3 including a rupturable adhesive between the male and female threads formed on the respective cups.
5. Apparatus as defined in claim 3 wherein said striker mechanism comprises a rod slidably supported by said cap.
6. Apparatus as defined in claim 3 wherein said thermosetting resin consists of a polyester resin.
7. Apparatus as defined in claim 3 wherein said thermosetting resin consists of an epoxide resin.
8. Apparatus as defined in claim 3 wherein said resin is reinforced with glass fibers.
References Cited by the Examiner UNITED STATES PATENTS 2,105,487 1/1938 Lozon.
2,204,015 6/1940 Iftiger et al.
2,426,024 8/1947 Jones et al. 16931 2,571,877 10/1951 HenshaW 169-31 EVERETT W. KIRBY, Primary Examiner.
J. HUSSER, Assistant Examiner.