Page:Popular Science Monthly Volume 47.djvu/626
610 THE POPULAR SCIENCE MONTHLY.
zle is generally wound with cord to give better holding surface, and again the solid body is replaced by a flexible pipe made of cotton-lined rubber wound with wire. This device enables the fireman to change the direction of the pipe when at close quarters. Spray and shut-off nozzles are used that can instantly reduce the size of the stream or change it into a fine spray. The ball nozzle is one of the latest inventions in this direction. A funnel-shaped opening contains a ball that, when not in use, is held in place by a light staple. When the stream is playing, however, the ball is forced into the opening by outside pressure and an extensive spray is the result. The cellar pipe is a modification of an ordi- nary nozzle. Being bent and in some cases formed in the shape of a letter S, it can be thrust through the floor and the stream easily delivered in any direction. A similar contrivance is used to extinguish a blaze between the ceiling and roof of a flat-roofed building. The distributing nozzle consists of a metal globe pro- vided with several nozzlelike outlets. This globe is attached to the end of a line of hose, and the force of the stream causes it to revolve and distribute a number of small powerful streams in every direction. This is especially efficient when hung in a sub- basement that is filled with smoke. There are also small sprin- kling nozzles used to clear a smoky room.
The enormous force of a fire stream renders it a difficult mat- ter to retain control, and many are the accidents reported of fire- men who have been disabled by failing to hold the nozzle. The Perfection nozzle holder, manufactured by Samuel Eastman & Company, of East Concord, N. H., is composed of two bars be- tween which the nozzle lies securely strapped. Two handles are on each side, and a removable bar is carried, that can be let down to the ground as a brace. An inner ring at the end of the nozzle, called the Hopkins patent, destroys the twisting tendency, and the ground brace carries off; any electric current with which the stream may come in contact. One man can safely direct a stream that ordinarily would require two or three to hold it.
Breaks in hose are mended by strapping a prepared sleeve to the injured part, or inserting a convex brass plate under the break and clamping to it a corresponding concave plate from the out- side. To facilitate pulling hose up a ladder, through a window, or over the edge of a roof, a simple hook-shaped frame, provided with rollers, called the Bresnan hose hoist, is used.
The absolute shut-off nozzles can not be used without bursting the hose, unless the engine or hydrant is provided with an auto- matic relief valve that will open and allow the water to run back into the suction pipe. The valve can be regulated to suit the pressure that the hose will stand. During the sixties several valves were tried, the first very successful one being that invented