US2311884A - Fire extinguishing - Google Patents

Description

OR 293119884 R Feb. 23, 1943. F. H. $T ElNlCKE FIRE EXTINGUISHING Filed Feb. 27, 1940 Seam m IZVENTORE BY M ATTO EY$ Patented Feb. 23, 1943 bediCil mum FIRE EXTINGUISHING Frank H. Steinicke, Elmira, N. Y., assignor to American-La France-Foamite Corporation, Elmira, N. Y., a corporation of New York Application February 27, 1940-, Serial No. 321,001

3 Claims.

The object of the invention is to safeguard the fireman against the danger of electrical shock, or even electrocution, in the event his hose stream contacts a live power line. In such case, current flows down the hose stream, passing through the firemans body to the ground. To guard against this consequence, it is customary to hold off the water until the power has been shut off, even though this may give the fire greater headway. To avoid such delay, it has been proposed to insulate the nozzle thus protecting the fireman, but that is of little use when it is wet, and any such nozzle is likely to be dangerous. It has also been proposed to weave copper wire into the hose fabric thus to provide an easier path for the current to reach the ground, avoiding the fireman, but none of these proposals has been accepted and the invariable custom is to shut off the current first and put the fire out afterwards. There is thus always a delay, often serious, in getting the water on the fire when electrical power lines are involved.

This invention enables the fireman to apply water to the fire without any uncertainty as to his own safety and therefore without any of the delay referred to.

I have found that if the nozzle of the fire hose is designed to deliver the water in a dispersed or finely broken-up condition, that is, in the form of spray rather than a solid stream, its electrical resistance is thereby so enormously increased that even in the case of very high potentials any current transmitted to the fireman is so little as to be harmless and further that the degree of dispersion necessary for obtaining this result is not so great as to impair objectionably the range of the delivered stream, so that the fireman can have an efiective stream to deliver on the fire and also a perfectly safe stream so far as electric shock is concerned.

For example, I have discovered that a nozzle giving a working stream of from to 85 feet in length, which can be produced within the range of water pressures commonly available, can be made perfectly safe for the fireman under all electrical conditions likely to be encountered. Such a spray stream has been tested with live wire potentials up to 250,000 volts and at distances from nozzle to live wire of as little as two or three feet and at varying water pressures, from the least that will produce any spray at all up to the highest available from a pumper, and in all cases was found to transmit much less than 3 milliamperes of current to the nozzle, which is the accepted safe maximum that the average human body can withstand without risk or discomfort.

The accompanying drawing shows a nozzle suitable for the purpose, partly in longitudinal section. It is threaded at its base end to screw on a standard fire-hose coupling and at its tip is provided with an orifice and a spreader l permanently fixed in a bridge 2 and so related to the orifice as to deliver the water as a spray cone which is initially hollow but which changes in a few feet where its cross section becomes more or less homogeneously filled with small water drops. The sufilcient degree of dispersion is obtained when a nozzle of this type delivers a spray cone with an included angle preferably of about 3U and not less than 25. Under a pressure as low as 25 pounds such a nozzle in the standard (2 /2 inch) size gives a 40 foot range of stream and at 100 pounds gives feet and at this pressure 16o gallons per minute are delivered on the fire. The electric resistance is so high that at a distance of 6 feet a live wire at 250,000 volts produces only 0.2 milliampere flowing through a grounded nozzle. At 10 feet which is perhaps the minimum likely distance, and only 20 pounds nozzle pressure, the current at the nozzle was recorded as zero, from which it will be observed that the resistance is high enough to reduce any current fiow to less than the danger point of 3.0 milliamperes.

I prefer that the spray nozzle be non-adjustable and therefore the spreader is permanently fixed to the bridge in the predetermined position. While no accident could occur from permitting its adjustment to give wider cone angles or greater dispersion, it is safer to have it nonadjustable and thus avoid the possibility of confusion with other nozzles of the adjustable type the improper use of which might involve serious danger. Thus with a nozzle built to give only the safe and longest range of spray stream, there is the least confusion and the least delay in making up the line. To the same end, the new nozzle is desirably configured or conspicuously marked in some way so as not to be confusibie with solid-stream nozzles. This is accomplished in the present case by the disposition of the holding loop or handle 3 at the base of the tip and by the presence of the spreader which is always visible at the orifice.

I am of course aware that spray nozzles have heretofore been proposed for extinguishing fires, the well-known sprinkler-head being one example, but the purpose in such and other nozzles has had no reference to the transmission of current of dangerous amperage and, so far as I am aware, they have not been available or utilized for the protection of human beings against electrical shock, nor for the elimination of the delay above referred to, which are the object and result of this invention.

I claim:

1. The method of protecting firemen from dangerous electric shock from current passing from high potential objects through the hose stream to the nozzle held by the fireman, which consists in converting such stream into a spray stream of finely divided water particles having such range and degree of subdivision as is produced by a spray cone of about 30 degrees, included angle, under a pressure of or upwards of about 20 pounds per square inch, and playing said stream upon a fire involving said objects.

2. The method of protecting firemen from dangerous electric shock from current passing from high potential objects through the hose stream to the nozzle heldby-the fireman, which consists in passing such stream through-a spray nozzle giving a spray cone angle of not less than about 25 at a pressure of-not less than about 20 pounds per square inch and thereby converting such stream into a spray stream of finely divided water particles having substantially uni form particle distribution throughout its crosssection and an electrical resistance capable of reducing current flow to less than 3 milliamperes at 10 feet, when the potential difference is 250,000 volts, and playing said stream upon a fire involving said objects.

3. The method of safely extinguishing fires involving objects at dangerous electric potentials, which consists in passin a stream of water under pressure through a suitable nozzle and thereby transforming it into a stream of fine spray particles, said particles being uniformly dispersed throughout the stream cross section and sufiiciently finely divided to give the stream an electric resistance substantially completely obstructing-current flow from said object to said nozzle, maintaining the lateral dimension of said stream within an included angle of about 30 and maintaining the pressure at least about 20 pounds and playing such stream upon the fire involving said objects of dangerous electric potential.

FRANK H. STEINICKE.

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