US1499631A - Fire extinguisher - Google Patents

Description

July 1 1924.

R. w. AUSTIN 'FIRE EXTINGUISHER Filed Sebt. 20. 1922 l H! II II ,I l l l l l 11in d; abIe Patented July 1, 1924.

UNITED STATES PATENT OFFICE.

Application filed September 20, 1922. Serial Il'o. 588,855.

To all'whom it may concern:

Be it known that I, RALPH W. AUSTIN, a citizen of the UnitedStates, residin at Quincy, in the county of Norfolk and tate of Massachusetts, have invented certain new and useful Improvements in Fire Extinguishers; and I do hereby'declare the followin to be a full, clear, and exact descriptlonof the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a fire extinguisher.

The invention has for an object to provide a novel and improved fire extinguisher of the type employing liquid chemicals for the generation of the gas pressure for exthe extinguishing li uid, which is of operating with 'gh efliciency at ow temperatures.

A further object of the invention is to provide a fire extinguisher of the character specified which is capable of operating under all conditions of use atmaximum etficienc Wit these ob'ects in view the invention consists in the lire extinguisher and comunds for use in a fire extinguisher, heremafter described and particularly defined in the claims at the end of the specification.

The drawing illustrates an extinguisher embodying the present invention and in which Fig. 1 is a vertical section and Fig.

2 is a detail on line 2-2 of F 1.

In the usual form' of fire extin isher at present upon the market, the car on dioxide "gas utilized for expelling the extinguishin liquid is generated by the reacphuric acid upon a solution of bicarbonate of soda. The soda and acid solutions are normally isolated from one another to be capable of mixture when the extinguisher is inverted. When such form of extinguisher is exposed to low temperatures, even the ordinary low temperatures encountered in the use of the extinguisher concentration of the soda decreases, the hquid soon freezes, causing rupture of the outer container At zero F. the extinguisher is in fact actually inoperative.

'The only approved form of anti-freezing fire extinguisher at present -u n the market utilizes chemicals in solid orm for generating the gas pressure to expel an antifreezing extinguishin liquid such. as con-- centrated calcium 0 orlde solution. In practice this form of fire extinguisher has not met with 'favor by the trade, being regarded unsatisfactory for various reasons, particularly because of the explosive nature of the solid chemicals employed and theuncertainty of the reaction between the:

chemicals. Attempts have also been made to produce a commercial anti-freezing extinguisher employing liquid chemicals, but at the present time so far as I am aware, with the one tion of an extinguisher embodying the eatures of the present invention, no anti-freezinglextinguishers employing li uid chemicals ave been ap roved by the ational Board of Fire Un erwriters or are found upon the market at the present time. p

In approaching the problem of the production of a commercial anti-freezing extinguisher employing liquid chemicals, potassium carbonate was selected as the basic chemical for the roduction of'the carbon dioxide gas for t e reason that of all of the soluble carbonates, ammonium carbonate, sodium carbonate, and potassium carbonate, the latter possessed a eutectic point in the pure form of -'36 C. whereas the eutectic point of the sodium carbonate was 2 C. Ammonium carbonate or bicarbonate because of their volatility and in-- stability under slight heat and pressure, were foundto be entirely unsuitable for practical use in an extinguisher. The National Board of Fire Underwriters require for an A-l rating that the extinguisher be capable not only of withstanding a temperature as low as 40 C. but that it should be capable of, operating with high efliciency at such temperature and be able' to develop pressure suflicient to throw an extinguishing stream at least 40 feet.

In practice with the commercial grades of tassium carbonate obtainable, it was. found impossible to obtain a potassium carbonate solution which would remain fluid at the temperature corresponding to the theoretical sium carbonate itself coul eutectic point, while the character of the crystallization occurri was such that the mass assumes a sort 0 semi-viscous state lacking the characteristic expansion of ice, and which as the temperature was lowered, becomes granular. This characteristic of the potassium carbonate solution of itself eliminates the liability of subjecting the extinguisher to bursting strains, thus contributing to the durability of the extinguisher. A large number of reagents were experimented with in the attempt to find one which when dissolved in the potassium carbonate solution would produce a composition having a eutectic point -40 C. All the organic materials which were suitable in this respect were found to require, because of their high molecular weights, the use of such a large quantity of the reagent as to preclude the possibility ofusing them in fire extinguishers of the size commonly used in practice. Of the inorganic reagents, all of those experimented with, with the exception of tha hydroxides, were found unsuitable for.

either one of tworeasons that the either formed an insoluble precipitatein t e form of a carbonate or hydroxide, examplesof such reagents being copper chloride, calcium chloride, iron chloride and zinc chloride, or

for the additional reason that they reacted with the carbonate to form the soluble chloride or salt such as otassium chloride, the eutectic points of w ich solutions were relatively high. The eutectic point of potassium chloride being 11 0., it is obvious that the eutectic oint of. potasd not be lowered by reagents which form salts,'such as potassium chloride, in the solution.

lPotassium hydroxide having a eutectic point of t35 (3., was round to lend itself admirably for use with potassium carbonate solutions, not only because of its low eutectic point but also because of the fact that it produced a common ion in solution, eliminating the formation of objectionable salts such as potassium chloride. ln addition, as

v will be pointed out, the potassium hydroxide assists materially in producing an extremely rap1d reaction between the acid and the carbonate at the low temperatures, thus assisting the instantaneous development or" high pressure at low temperatures and enabling the extinguisher to operate with high eficiency.

. For the production of an anti-freezingextinguisher, it is necessary to employ an acid which is likewise capable of withstanding the low temperatures without freezing, and it has been found that sulphuric acid of concentrations by weight between the limits of 55.25% and 74.5% possess freezin points of -40 C. and lower. It is pre erred to employ a suficient quantity of sulphuric acid of a concentration by weight of 74.5%,

In the referred form of extinguisher, an .extinguis ing liquid comprising a solution of ca um chloride of sufiicient concentration to be capable of remaining liquid when exposed to a temperature of 40 C. is employed. The carbonate solution is preferably made up in proportions corresponding to'2 lbs. ofpotassium carbonate dissolved in 3 lbs. of water and to which i lb. of potassium hydroxide is added. A suflicient'quantity of 74.5% by weight sulphuric acid is preferably employed. The carbonate and acid solutions are normally isolated and may be contained in separate containers.

Referring to the drawing, the extinguisher illustrated therein comprises a metal container 10 of usual shape having the usual opening 12 in the top thereof through which the charge of extinguishing materials are introduced, and having an outlet or discharge nozzle 14 of usual construction. The opening 12 is normally closed by a metal cap (not shown) screwedupon the threaded neck of the container 10. The container 10 is normally filled to approximately the indicated level with an anti-freezing solution, which may and preferably will comprise a water solution of calcium chlorideof suficient concentration to withstand temperatures be tween 40 F. to 55 F.

The carbonate solution, preferably potassium carbonate solution, containing the potassium hydroxide, and the sulphuric or other acid necessary for the generation of the gas pressure for the operation of the extinguisher are normally maintained within the container 10 in separate containers 22, 24, the latter being supported within the former and both being normally maintained in a position such as to prevent mixture as long as the'extinguisher is held upright or in the position illustrated in Fig. 1. The container 22 comprises an annular metal receptacle of the shape illustrated in Fig. 1, preferably of brass, and which is secured to and supported by a ring 21 resting upon a shelf 25 projecting inwardly from the neck of the container as shown. A cap member 28 is screwed into the ring 21, normally closing the container 22. In the preferred manner of construction, the container 22 comprises a brass tube within which the second tube 23 is positioned, the latter being sup orted at its bottom upon a tube 30, sol cred or otherwise secured to the bottoms of the tubes 22, 23, and arranged to register with preformed holes in the bottoms of these tubes to form 1 passage from the interior of the tube 23 through the lower art of the tube 22, for a purpose to be descri ed. The sulphuric acid is contained in a separate container 24, preferably compmsmg the usual bottle, and which is supported by indentures 26 projecting from the tube 23, and retained in a centralized position by similar indentures 29 arranged to engage the sides of the bottle. The sulphuric acid bottle 24 is provided with the usual form of lead stopper to normally close the mouth thereof while the extinguisher is in upright position. The stop er is provided wlth the usual shank extended down into the bottle and of suflicientlen h to center the stopper when the extinguis er is inverted and the stopper has fallen a ainst the bottdm of the cap 28.

Guard mem ers 36 arearranged to depend from the bottom of the cap 28 and to engage the body of the sulphuric-acid bottle in order to removably retain it within its container. The ends of arms 37 extended laterally from the guard members 36 are arranged to hook over the tube 23 to support the top thereof. The tubes 22, 23, bottle 24, cap 28 and ring 21 constitute a unitary structure, which may be easily removed from the extinguisher. casing. These parts are normally retained in position upon the shelf by gravity and by the extinguisher cover (not shown) which is screwed onto the neck of the extinguisher.

From the description thus far, it will be observed that the carbonate solution forming the basis from which the carbon dioxide gas is generated is retained in such position that w en the extinguisher is inverted the carbonate solution flows downwardlyfrom the interior of the container 22 through the annular passage surrounding the, tube 23 into a chamber 38 which may be regarded as a mixin chamber. The sulphuric acid from the bott e 24 at the same time flows directly into this mixing chamber 38. As the carbon dioxide gas is generated, it is caused to pass through the annular passage between the interior of the tube 23 and the sides of the bottle 24 and thence throughthe tube 30 to the bottom of the extinguisher, it being understood, of course, that the extinguisher in an inverted position, the carbon bein ' dioxide gas rises in the manner described through the space between the bottle 24 and tube 23 through the tube 30 into the air space above the extin ishing liquid within the container 10. e development of a large gas pressure above the extinguishin iiquid servestoeffectively force it throug the outlet nozzle 14 in the desired stream. With this construction it will be observed that the mixing of the sulphuric acid and carbonate solution is caused to take place in a chamber separated from the outlet or discharge nozzle 14 so that there is no liability of the extinguishing stream issuing the nozzle 14 containing any sulphuric acl In the operation of the extinguisher and particularly at very low temperatures, when .which would otherwise be formed from a hydroxide, the concentration of the suphuric the extinguisher is inverted as the acid flows into contact with the carbonates and hyaction between the acid and the hydroxide according to the following equation? The development of this large quantity of heat immediately raises the temperature of the reacting materials, causing the rate of the reaction between the acid and the carbonate to be raised to a point such that the desired gas pressure'is almost instantaneously built'up within the extinguisher, thus enabling the extinguisher to o rate immediately after it has been inverte with maximum efficiency. The presence of the potassium hydroxide in the carbonate solution is also important in that it retains the carbonate in solution even when the extinguisher is exposed to extremely low temperatures such as. are encountered in the northern countries, such as Canada.

While it is referred to em loy potassium carbonate an basic chemical or reaction with an acid to produce carbon dioxide gas in the extinguisher, it is not desired to limit the invention in this respect for the reason that the use of a hydroxide in connection withv sodium carbonate is of advantage in respect to the development of heat by the reaction of-the acid and hydroxide and which results in increasing the rapidity of the reaction between the acid and the carbonate, thus enabling the desired gas presure to be built up instantaneously. In addition, of course, the development of the heat within the extinguisher operates to increase the pressure given quantity of reacting materials, so that m this respect the extinguisher is enabled to throw a stream a eater distance than otherwise would be t e case were not the hydroxide to be used.

Having thus described the invention, what is claimed is 1. In a fire extin isher, an anti-freez' extinguishing liqui capable of withstan ing a temperature of 40 F. without freezing, and chemicals in liquid form for expelling the extinguishing liquid comprising a normally isolated solution of sul huric acid and a normally isolated. solution of V potassium carbonate containing potassium acid solution and the proportions of potassium carbonate and potassium hydroxide in the carbonate solution being such that both.

solutions remain fluid at a temperature of -40 F.

2. In a fire extinguishenan'extinguishing liquid capable t: wi hstanding a otassium hy roxide as the.

'ture of -40 F. without freezing, a normally isolated acid solution capable of Withstancling a temperature of -40 F. without freezing, and a normally isolated solution of potassium carbonate containing potassium hydroxide in the proportions of 2 lbs. of potassium carbonate and lb. potassium hydroxirie in 3 lbs. of Water.

3. In a fire extinguisher, an anti-freezing extinguishing liquid, and chemicals for expelling the extinguishing liquid including a normally isolated acid solution capable of withstanding a' low temperature Without freezing and a normally isolated potassium carbonate solution containing a potassium hydroxide solution.

in a fire extinguisher, in combination, an anti-freezing extinguishing liquid, a normally isolatecl sulphuric acid solution of a concentration between 74.5% and 65.25%

by weight, and a normally isolated mixture 5. In a fire extinguisher, a normally isolated. acid solution and a normally isolates;

carbonate solution containing an hydroxide in solution.

6. A carbonate solution for fire extinguishers comprising as essential ingreclients, gotassium carbonate and potassium hyroxide said ingredients being in suiiicinet amounts that the carbonate solution will not freeze at about 40 F.

7. A carbonate solution for fire extinguishers comprising as essential ingredients otassium carbonate and potassium hyclrcav ide substantially in the proportions of 3 to 1.

RALPH W. AUSTIN.

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