GB2161379A - Hand-grenade type fire extinguisher - Google Patents

Abstract

A hand-grenade type of fire extinguisher comprises a hollow sealed vessel adapted to break on impact, charged with an aqueous solution containing ammonium chloride and an alkali metal carbonate in a molar ratio of over 1.5:1 and at an ammonium chloride concentration of at least 13% by weight. In a preferred embodiment a predetermined quantity of an inorganic mixture consisting of 52% of ammonium chloride, 6% of sodium bicarbonate, 31% of potassium carbonate and 11% of diammonium hydrogen phosphate, by weight, is dissolved in a quantity of water of a weight of between about 2.5 to about 2.8 times that of the mixture, at a temperature of between 45 DEG C to 50 DEG C, and a predetermined quantity of the resultant solution is transferred and packed light-tightly into a thin rectangular container of a synthetic resin shaped with due regard to the weatherability and breakability thereof.

Description

SPECIFICATION Hand-grenade type fire extinguisher Background of the invention Heretofore known fire extinguishers of the so-called "hand grenade" type are mostly manufactured by packing powder chemicals into a container or shell of an appropriate shape, and are said to be extremely easy to use. However, it seems doubtful that their shapes and fire-extinguishing chemicals are chosen for their durability, or are based upon a clarification of the mechanism of how these shapes and chemicals exhibit an effective fire-extinguishing action on combustible materials through the physical and chemical changes thereof that occur when they are used in practice.

Summary of the invention The present invention relates generally to a fire-extinguisher of the hand grenade type formed by packing a solution of fire-extinguishing chemicals into a thin, rectangular resin container. More particularly, the present invention makes use of a solution prepared by dissolving a mixture of potassium and calcium compounds and ammonium salts in water as a fire-extinguishing agent, a predetermined quantity of this solution is packed into a thin rectangular vinyl container of an easy-to-throw shape so that when the container is thrown into the base of a fire, the container will break and the liquid agent will decompose and diffuse thereby to deprive combustible materials of heat and oxygen, and ensure that the fire is extinguished in its initial stages.

Brief description of the drawings The accompanying drawings illustrate one embodiment of the present invention, in which: Figure 1 is a front view of a hand-grenade type of fire extinguisher; and Figure 2 is a section therethrough.

Description of the preferred embodiment Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

(1) The fire-extinguishing agent is prepared in the following way. The following components (a) through (d) are charged at 45 to 50"C and at predetermined intervals in the order named into a solution tank which has a capacity of 500 ç and is equipped with a stirrer, and which contains between 300 to 350 ( water: (a) NH4Cf ... 76.5 kg (b) NaHCO3 ... 9.0 kg (c) K2CO, ... 45.0 kg (d) (NH4)2HPO4 ... 15.8 kg The stirring time varies according to the solubility of each solute. The time required for the dissolving is about 30 minutes for component (d), and between about 50 to 60 minutes for the others. A homogeneous solution is formed within 3 to 4.5 hours, and no precipitate remains within the solution tank.Thereafter, between 100 to 150 { of water is charged into the tank to dilute the solution to provide a total of between 400 to 450 4 thereof. The resultant solution is then transferred into a container 1 (see Figure 1).

The liquid phase is colorless and transparent, its specific gravity is 1.15, and its pH is between 9 to 10.

1,000 cc of this solution contains 100 g of K2CO3 (anhydride), 170 g of NH4C4, 35 g of (NH4)2HPO4 and 20 g of NaHCO2. The reaction produced by the dissolving of the raw materials is expressed by the following formula: 2NH,Ct + K2CO3 > 2KCf + 2NH4CO3 Within burning materials the NH4CO3 rapidly decomposes, as expressed by the following formula: 2NH4CO; < 2NH3 + 2CO2 + H2O In other words, the ammonium chloride and potassium chloride react with each other, although slightly, at normal temperatures as expressed by the formula below, and generates a weak smell of ammonia:: 2NH4CI t K2CO, < 2NHs + CO2 + 2KCI + H2O.

This reaction proceeds more rapidly as temperature rises, and vigorously in a fire. The resultant ammonia reacts further with oxygen and is decomposed as expressed below: 4NH3 + 30 - 2N2 + 6H2O Accordingly, the air (oxygen) is rapidly removed as Cho2, N2, NH3 and H2O (steam) gases, thereby suppressing combustion.

Diammonium hydrogen phosphate is generally known as a flame retardant, and is used in fire extinguishers. In the present invention, this compound contributes further to effective fire extinguishing as a result of the synergistic effects of the above reactions. Sodium bicarbonate restricts the reactions and functions as a stabilizer at normal temperatures, but at higher temperatures, it is decomposed to generate CO?, and thus contributes to the fire extinguishing.

Among the chemicals that are released after the fire-extinguishing agent of the present invention is thrown into a fire, the remaining materials which are not gasified, the chlorides, phosphates, etc., cover combustible materials and prevent them igniting again. They also prevent the spread of fire. Needless to say, the enormous heat of vaporization (endothermy) of the water in which these chemicals are dissolved, and the removal of the air by the resultant steam, exhibit an effective fire-extinguishing action.

The solution tank is made of a thick sheet of stainless steel or a rigid resin material, and is equipped with a lid. The attached stirrer is of a 100 V 100 W, 300 r.p.m. type.

(2) A 0.8 -1.0 mm thick sheet of red vinyl ch vride ("Compound", trade name) is used for the main contained body. The container is a rectangular bottle 1 whose base 4 is 80 mm by 80 mm square and whose height is 160 mm. An L-shaped curved portion 2 continues a filler port 3 at the top thereof. Protuberances a b, c, d, e, which project 2 mm from the peripheral surfaces, are formed so as to encompass the rectangular bottle, while recesses d', e' are defined within the container at positions corresponding to the protuberances. The width of each protuberance is 12 mm for a, 10 mm for b, 8 mm for c, 10 mm for d, and 12 mm for e, so that the protuberances b, c, and d at the center are narrower than the protuberances a and e. This arrangement makes it easier to grip and throw the container.The corners at which the peripheral surface and the protuberances meet are rounded to provide a smooth feel. Its color (red) is familiar as that of fire prevention equipment, so is used so that anyone can easily notice the container and throw it. The cap of the container is made of white polypropylene ("Alon compound", trade name) and packing is made of polyethylene ("Softlon", trade name) of a natural color.

A predetermined quantity, i.e., 800 cc, of the fire-extinguishing solution is charged into the rectangular container and is hermetically sealed therein. The temperature at which the container can be stored is between -10-C to 50"C All the chemicals are of food-additive grade, and hence are completely harmless.

The chemicals can be used effectively for more than five years, so long as no strong physical impact is applied to their container.

The following are results (except) of test on the performance of the fire extinguishing hand grenade of the present invention, done by Nippon Fire Prevention Equipment Safety Center (Tokyo).

Date of test: September 7, 1983 Water content of Wood: 15% Prototype of fire model: No. 2 prototype Pre-burning time: 3 minutes No. Number of Throw Thrower throws time (age) Result 1 3 12 sec male, 48 Not extinguished 2 3 19 " ", 75 Extinguished 3 3 14" ",75 " Remarks: One sample in the first trial did not hit the fire.

Table 2 Results of weatherability tests (1) Exposure tests Period: September 8, 1983 -October 7, 1983 (2) Breakage tests Samples before exposure test Samples after exposure test Sample No. Breakage pressure Sample No. Breakage pressure 1 2.8kg 4 2.8 kg 2 2.5" 5 2.8" 3 3.0" 6 2.8" Fire extinguishers and fire-extinguishing equipment (which replace buckets filled with water) are all directed to extinguishing indoor fires at an initial stage, and various types such as installed types, throwable types, jet types, etc., are available. However, all of them require a mechanical procedure. Once confronted with a fire, however, people are likely to temporarily lose presence of mind, and more often than not, they can not utilize such fire extinguishers effectively. Since the fire extinguisher of the present invention is an entirely novel type which can be operated simply by picking up the container and throwing it into the fire, not only adults but also children can easily handle the fire extinguisher. In comparison with conventional devices, the fire extinguisher of the present invention has a better construction and effect, exhibits a reliable fire-extinguishing effect in any fire (indoor fire), and can prevent the spread of fire.

Claims (9)

1. A fire extinguisher of the "hand-grenade" type comprising a hollow sealed vessel adapted to break on impact, charged with an aqueous solution containing ammonium chloride and an alkali metal carbonate in a molar ratio of over 1.5:1 and at an ammonium chloride concentration of at least 13% by weight.

2. An extinguisher according to claim 1, in which the solution further contains an alkali metal bicarbonate at a concentration of at least 1.5% by weight.

3. An extinguisher according to claim 1 or claim 2, further containing another fire-retardant component.

4. An extinguisher according to any of claims 1 to 3, in which the solution further contains diammonium hydrogen phosphate at a concentration of at least 2.5% by weight.

5. A hand-grenade type of fire extinguisher according to any of claims 1 to 4 produced by dissolving a predetermined quantity of an inorganic mixture consisting of 52% of ammonium chloride, 6% of sodium bicarbonate, 31% of potassium carbonate and 11% of diammonium hydrogen phosphate, by weight, in a quantity of water which is between about 2.5 to about 2.8 times the weight of said mixture at a temperature of 45" to 50", and transferring a predetermined quantity of the resultant solution into a light-tight thin rectangular vessel of a synthetic resin the container being durable, easy to throw and suitably breakable.

6. An extinguisher according to any of claims 1 to 5, in which the vessel is constructed of a breakable vinyl chloride resin.

7. An extinguisher according to claim 6, in which the vessel is a bottle of approximately square cross section with moulded transverse ribs to aid hand grip.

8. An extinguisher substantially as described with reference to the drawings.

9. An extinguisher according to claim 1 and substantially as herein described.