US3028918A - Inner charge container for fire extinguishers - Google Patents

Description

April 10, 1962 c. K. HUTHSING, SR 3,028,918

INNER CHARGE CONTAINER FOR FIRE EXTINGUISHERS Filed Jan. 29, 1959 44 ny Y 44 I a l INVENTOR.

United States Patent @fifice 3,928,918 Patented Apr. 10, 1962 3,tl28,918 INNER CHARGE CONTAINER'FOR FKRE EXTlNGUISI-IERS Charles K. Huthsing, Sn, Culver City, Caiifi, a'ssignor to The General Fire Extinguisher Co. of Pennsylvania,

Philadelphia, Pa e corporation of Pennsylvania Filed Jan. 29', 1959, Ser. Ne. 789,873 1 Claim. (Cl. 169-32) The present invention pertains to an improved fire extinguisher construction and more particularly to an improved container of molded plastic construction especially suited for use in a pressure generating type fire extinguisher for holding a liquid reagent therein.

One important object of the present invention is to provide an improved fire extinguisher container of high- 1y corrosion resistant and long lasting yet inexpensive construction.

Other objects of the invention are: to provide an improved container for use in a pressure generating type fire extinguisher, which is long wearing, and highly corrosion resistant, yet inexpensive to manufacture; to provide an improved elongated tubular container of molded construction and method of making it, the container having an integrally molded closure at one end and an in tegrally molded inturned flange at its other end; to provide an improved elongated tubular container of molded plastic construction comprising two end-to-end slightly tapered tubular portions sealingly spliced together by means of a molded adapter ring, the container being relatively inexpensive to manufacture, and corrosion resistant to any desired degree, depending upon the material of which it is molded.

The foregoing and other objects and advantages of the present invention will become apparent in the following detailed description of a preferred embodiment thereof, taken in conjunction with the drawing, wherein:

FIGURE 1 is an exploded perspective view of a molded plastic inner container for use in a first extinguisher according to the present invention;

FIG. 2 is a cross-sectional view, partly in elevation showing the container installed in an otherwise conventional pressure generating type fire extinguisher; and

FIG. 3 is a fragmentary cross-sectional view partly in elevation showing the extinguisher illustrated in FIG. 2 in an inverted position.

The pressure generating type fire extinguisher shown in the drawing includes a molded plastic inner container it} according to a preferred embodiment of the invention supported within an outer casing, or pressure vessel 12, which as shown is of entirely conventional construction. Normally, the outer casing 12 is filled with a water solution of soda, and a liquid reagent such as a solution of aluminum sulfite, capable of rapidly generating gas when mixed with the soda solution, is placed within the inner container 10. The fire extinguisher is normally stored in an upright position, as shown in FIG. 2. In the event of a fire, the extinguisher is usually inverted, whereupon the reagent within the inner container flows out of the inner container 10, and mixes and reacts with the soda solution in the outer casing 12, generating gas under relatively high pressure, which acts to drive the soda solution and the spent reaction mixture out of the casing 12 through the nipple 14 and the hose 16.

A fire extinguisher is ordinarily emergency equipment, and is kept on stand-by for long periods of time, during which it must retain its ability to generate pressure, so that when an emergency arises and the extinguisher is put to use, it will be effective for its purpose. it is important, therefore, that the inner container 14} be im pervious to liquids, and corrosion resistant, so that the reagent contained within the inner container 13 does not leak out duringstand-by, periods and become mixed with the soda solution in the outer casing 12, thereby dissipat ing theability of the extinguisher to develop pressure when it is called into service. The inner container It therefore, must be leakproof and must be able to withstand the corrosive eifects of the soda solution 12 and of the foam generating reagent stored within the inner container 10 for long periods of time without developing even so much as a pinhole leak;

The inner container of fire extinguishers of this type have heretofore been made of sheet metal coated with a waterproofing and corrosion preventive material. It has been relatively difficult to make such sheet :metal containers water-tight and sufficiently corrosion resistant to retain their water-tight characteristics over relatively long periods of time. In the sheet metal construction, the container is made from a flat piece of. sheet metal, and includes a longitudinal seam extending for its full length, which must be soldered or welded, and a separate bottom member, which also must be soldered in place. The seams and joinings increase the difiiculty of applying a uniform protective coating and thereby serve to promote corrosion and leakage, besides involving a relatively high manufacturing cost.

According to the present invention the inner container 11'! is formed of noncorrosive molded plastic or other suitable material, and includes an integrally molded bottom closure 26, and an integrally molded inturned top flange 22 for supporting the stopple 24, which normally closes the upper end of the container 10. The container 10 is molded in four pieces, and includes a bottom portion 26, an upper tubular portion 28, a splice ring 32, and an upper guide portion 30, all of which are cemented together to form a sturdy container. The guide portion 39 guides the stopple 24 when the fire extinguisher is inverted during operation and insures proper return of the stopple to its seated position upon the flange 22 when the extinguisher is returned to its normal upright position.

The container 10 is relatively long and of narrow diameter, and because of its proportions, as well as its integrally molded bottom closure 20 and inturned flange.

22 at its upper end, it is not practical to mold it in a single piece, as the molded one piece container could not be withdrawn from the mold. The bottom portion 26 and the upper portion 28 are, therefore, molded sepa rately and are joined together with or without the adapter, or splice ring 32, by pressing said parts together and by securing and sealing them by means of an appropriate cement (not separately designated). The bottom portion 26 is tapered so that it is of slightly greater diameter at the top than at the bottom, in order to facilitate withdrawal of the molding mandrel, or core member during manufacture, and the upper portion 28is made slightly wider at its lower end than at its upper end for the same reason.

The mating ends of the two portions 26 and 28 are made of substantially the same diameter so that they form a smooth juncture at the middle of the container. The splice ring 32 is provided with an outwardly projecting flange 34 about midway along its length and of a height about equal to the thickness of the wall section of the two portions 26 and 28. The flange 34 acts as a stop when the splice ring 32 is inserted in either one of the portions 26 and 28, and insures that the splice ring I be made of lead or any other desired material. An exterior shoulder 36 and an axially projecting flange 38 are formed at the top of the upper portion 28 for receiving the guide portion 38, the bottom ring 49 of which fits tightly around and is cemented to the flange 38.

The guide portion 30 includes an outwardly extending flange 42 at its upper end for supporting the inner container 10 within the fire extinguisher. The flange 42 rests upon an inwardly projecting flange 46 of the collar 44, which reinforces the top of the outer casing 12. The flange 46 has an inside diameter just greater than the greatest diameter of the container ltl, and thus permits the inner container 10 to be readily inserted into and removed from the outer casing 12,. The flange 42 at the top of the guide portion 30 engages and rests upon the collar flange 46 for supporting the inner container 10 within the fire extinguisher. The handwheel cap 52 fits upon the collar 44 and abuts the top of the flange 42, thereby limiting upward movement of the container 18 and securing it in position.

The side walls 48 of the guide portion 30 are apertured as at 59 to provide ready discharge of the contents of the container 10 into the outer casing 12 when the fire extinguisher is inverted to the position shown in FIG. 3. The side walls 48 of the guide portion serve to hold the stopple 24 when the extinguisher is inverted, and to guide the stopple so that it will fall back properly upon the flange 22 when the extinguisher is restored to its normal upright position.

The inner container 10 may be molded of any desired rnoldable material, such as a synthetic resin, hard rubber or the like, having the desired corrosion resistance and strength properties. Polyethylene has been found to be suitable for most presently known fire extinguisher uses, since it is relatively inexpensive, is easily moldable, and is substantially inert to most presently used chemicals, as well as having excellent physical properties, such as tensile strength and resilience.

What is claimed is:

An elongated tubular container of molded plastic construction for use in a pressure generating type fire extinguisher or the like as the inner charge container thereof comprising a tapered generally tubular bottom portion having an integrally molded bottom closure and an open top, said bottom portion being wider at its top than at its bottom end, a tapered generally tubular upper portion having a relatively wide lower end and a relatively narrow upper end and an inwardly offset axially extending flange near its upper end, the lower end of said upper portion being of substantially the same diameter as the upper end of said bottom portion, a splicing ring fitted within both of said portions and sealed thereto for joining said portions together, and a separately formed stopple guide secured to said axially extending flange and extending upwardly therefrom, said guide being generally tubular in shape and having a perforate circumferential wall to permit lateral flow of fluid therethrough, said guide also having an annular, radially outwardly projecting flange at its upper end for axially supporting said inner container within a conventional fire extinguisher casing.

References Cited in the file of this patent UNITED STATES PATENTS 1,170,927 Moore Feb. 8, 1916 1,646,226 White Oct. 18, 1927 1,788,375 Banfil Jan. 13, 1931 1,973,734 Thomas et al. Sept. 18, 1934 2,751,025 Austin June 19, 1956 2,838,261 Amos et al. June 10, 1958 FOREIGN PATENTS 34,569 Norway Apr. 3, 1922 535,840 Great Britain Apr. 23, 1941

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