Fire extinguishers – Portable vessels – Gas pressure
Reexamination Certificate
1999-06-03
2001-03-20
Morris, Lesley D. (Department: 3752)
Fire extinguishers
Portable vessels
Gas pressure
C169S046000, C169S054000
Reexamination Certificate
active
06202755
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates broadly to an agent usable as an extinguishant, a method of preparing the fire extinguishing agent, and several uses of the fire extinguishing agent.
2. State of the Art
It is well known that halogenated hydrocarbons, or halons, are very effective fire extinguishing agents. Halon 1301 (CF
3
Br) has been in widespread use for “total flood” applications; that is, applications in which the agent is stored and discharged into occupied spaces such as computer facilities and restaurant kitchens, often by an automatic discharge or sprinkler system. Halon 1211 (CF
2
ClBr) has slightly greater toxicity but, due to its effectiveness, is extensively used for hand-held tank and outdoor mobile “streaming” applications, particularly for jet fuel fires. Halon 1211 and Halon 1301 have also been mixed together to provide a multipurpose extinguishing agent.
The halons operate as fire extinguishants by a complex chemical reaction involving the disruption of free-radical chain reactions to effectively remove oxygen from the fire and extinguish a fire. In addition, the halons are clean as well as effective, because they leave no residue and because they do not damage equipment or facilities to which they are applied.
However, the halons have several limitations. First, it has been determined that the halons have an ozone depleting effect. The halons break down into chlorofluorocarbon components which react with and thereby remove ozone from the atmosphere. Therefore, there has recently been a push away from halons and toward finding alternatives which are as effective. However, although a large amount of research has been conducted to find a replacement, none of the candidates has proven to be as effective as halons, and at the same time harmless to the environment.
Second, due to the complex chemical reaction which occurs during extinguishment, the halons operate best in either a closed space, where there is a contained oxygen supply, or in very close proximity to the fire. They are not as effective in outdoor use where the oxygen supply surrounding the fire is abundant, particularly when sprayed from large distances toward a fire. Therefore, they are not particularly effective in extinguishing fires when sprayed at a distance from the flames.
Third, even the halons do not provide as effective an extinguishment as desired. For example, while the halons extinguish the flames of a fire, they do not permit timely re-entry of a previously burning building or timely handling of a previously burning object due to the remaining heat. Moreover, the halons do not prevent reignition of a fire at the location of a previously extinguished fire.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a fire extinguishing agent which is more effective than using either Halon 1211 and Halon 1301.
It is another object of the invention to provide a fire extinguishing agent which extinguishes a fire, removes heat from a fire, and retards reignition of the fire.
It is a further object of the invention to provide a fire extinguishing agent which is relatively safe for the environment.
It is an additional object of the invention to provide a fire extinguishing agent which can be used indoors or outdoors.
It is also an object of the invention to provide a fire extinguishing agent has relatively low toxicity.
It is still another object of the invention to provide a fire extinguishing agent which may be used in a great number of applications.
In accord with these objects, which will be discussed in detail below, a preferred fire extinguishing agent includes an oxygen depleting agent, a heat removing (endothermic) agent, and a flame retarding agent. According to a preferred embodiment of the invention, the oxygen depleting agent is preferably a halon gas mixture of equal parts Halon 1211 and Halon 1301, the endothermic agent is preferably carbon dioxide, and the flame retarding agent preferably includes an aqueous solution of baking soda (potassium chloride), a liquid flame retardant, or a combination thereof. The fire extinguishing agent, which may be provided in gas, liquid, or powder form, is preferably pressurized with nitrogen or another inert gas. More particularly, the agent preferably comprises forty percent halon gas mixture of equal parts Halon 1211 and Halon 1301, twenty percent carbon dioxide, and forty percent flame retarding agent consisting essentially of a liquid flame retardant and small amount of the aqueous solution of baking soda.
The fire extinguishing agent extinguishes a fire, removes heat from the fire and material which was burning, and retards reignition of the fire. As a result, the area of an extinguished fire may be occupied immediately subsequent to use of the fire extinguishing agent. In addition, the agent is suitable for both indoors and outdoor use, and effectively extinguishes a fire even when streaming flames from a distance.
According to a preferred aspect of the invention, the components of the agent are provided under pressure of the pressurant gas into an aqueous solution in a container, e.g., a fire extinguisher tank. According to a preferred aspect of the invention, the Halon 1211 and Halon 1301 are forced through a filter, and preferably a diesel fuel filter, prior to entering the pressurized container. The filter removes and collects reactive chlorofluorocarbon constituents from the halon gases. As a result, the fire extinguishing agent, upon dispersion from the container into a fire, is relatively more environmentally friendly than prior fire extinguishing agents.
The fire extinguishing agent may be used in a variety of fire extinguishing applications. In addition to hand-held fire extinguishing tanks, which may be used in the home, computer rooms, kitchens, airplanes, etc., the fire extinguishing agent may be used in flood and streaming applications, may be used to fight forest fires, and may be used in a tanker truck, among other applications. Furthermore, the fire extinguishing agent is suitable for extinguishing A-class (solid), B-class (liquid), and C-class (electrical) fires.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.
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Fidelity Holdings Inc.
Gallagher Thomas A
Gordon David P.
Jacobson David S
Morris Lesley D.
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