A Catechism of the Steam Engine

by C. E. John Bourne

A, steam pipe leading from the boiler. B, a perforated tube or cylinder, through which the steam passes into the space b. C screwed rod for regulating the passage of steam through the annular conical space c, and worked by the handle d/. E, suction pipe, leading from the tank or hot well to small chamber m. F, annular conical opening or discharge pipe, the size of which is regulated by the movement of the tube or cylinder B. G, hand wheel for actuating the cylinder B. H, opening, in connection with the atmosphere, intervening between discharge pipe F and the receiving pipe through which the water is forced. I, tube through which the water passes to the boiler. K, valve for preventing the return of the water from the boiler when the injector is not working. L, waste or overflow pipe. M, nut to tighten the packing rings g and upper packing i in cylinder B. N, lock nut to hold M.

The pipe A is connected with the steam space of the boiler at its highest part, to obtain as dry steam as possible. The passage of the steam into A is controlled by a cock, as is also the feed pipe to the boiler. In working, both are opened, the steam passes through A into the space b, and issuing through the nozzle c with the pressure due to its head, and a partial vacuum by its contact with the feed water, it drives this water in connection with the jet through the pipe F into the pipe I in connection with the water space of the boiler.

Method of Working.--Turn the wheel so as to permit a small quantity of water to flow to the instrument. Open the steam cock connecting the apparatus with the boiler. Turn slightly the handle, which will admit a small quantity of steam to the apparatus; a partial vacuum is thus produced, causing the water to enter through the supply pipe. As soon as this happens, which can be observed at the overflow pipe, the supply of steam or water may be increased as required, up to the capacity of the instrument, regulating either by means of the wheel and handle, so as to prevent any overflow. The quantity of water delivered into the boiler, may be varied by means of the stop cocks on the steam and water pipes, without altering the handles on the injector; a graduated cock on the water supply pipe is very convenient for this purpose.

The machines are manufactured by Wm. Sellers & Co. Philadelphia.

As an example of Portable Steam Engines, of which there are large numbers in this country of different manufacturers, we give the representation (fig. 67) of one made by J.C. Hoadley, of Lawrence, Mass.

In these machines, the rules and proportions of the locomotive engine are adapted to the requirements of stationary power, for all purposes under forty horse power. The leading ideas are: high velocity, high pressure, good valve motion, large fire-box, numerous and short flues, and steam blast. The characteristic features are: great strength of boiler, fully adequate to bear with safety 200. lbs. pressure per sq. in., great compactness and simplicity, large and adjustable wearing surfaces, and the entire absence of all finish, or polish, for mere show.

The cylinder is placed over the centre of the boiler, at the fire-box end, so that the strain due to the engine is central to the boiler (which serves as bed plate); the starting valve is under the hand of the engineer when at the fire door; and both ends of the crank shaft are available for driving pulleys.

For the sake of compactness, the cylinders are set low, by means of a depression in the boiler between the stands of the crank shaft, to admit of the play of the crank and connecting rod. All the parts are attached to the boiler, which is made of sufficient strength to bear all extra strain due to the working of the engine.