A represents the receiver, made either of wood or metal. B B B wooden or cast-iron pipes for conveying the water to the receiver, and thence to the pen stock or cistern C. D the water-wheel. E the boiler; F the hot well for supplying the boiler with water. G G two cisterns under the level of the water, in which the lesser pipes, B B, and the condenser, are inserted. H H H the surface of the water with which the engine and the water-wheel are supplied. a a, the steam-pipe to convey the steam from the boiler to the receiver; b the feed-pipe, to convey hot water to the boiler from the hot well F. c c c, condens * apparatus • d d, the pipe which conveys the hot water from the condenser to the hot well. e e e, valves for admitting and excluding the water. f f, the injection-pipe; g the injection cock, and A the condenser. Before any water can be delivered on the wheel D, the receiver, the cistern 0, and all the pipes must be previously filled : the valve c is opened, and the steam rushing from the boiler into the receiver A, the water descends through the first pipe B, and pass ing the valve e, ascends through the second pipe B into the cistern C. The communication between the boiler and the receiver A being closed (by a valve not shown in the engraving,) the steam enters the condensing-pipe c, and in its passage meets with a jet of cold water from the injection-cock g, by which it is condensed ; and a vacuum being made by this means in the receiver, the water is driven up by atmospheric pressure into the pipe B, and becomes in like manner operated upon by opening the receiver valve. The water thus raised into the cistern C, falling through tlfe escapement pipe at the bottom upon the fans of D, gives.motion to the wheel.
The advantages possessed by an engine so constructed are stated the in ventor to be these :—That it is subject to little or no friction • has every facility which may be attributed to Bolton and Watt's engines by condensing out of the receiver, either in the cistern or at the level of the water; that the water in the upper part of the pipe which adjoins the receiver acquiring, by its frequent con tact with the steam, a heat nearly equal to that of boiling water, is kept uniformly hot, as in the case of Bolton and Watt's engines; and that a very small stream of wateris sufficient to supply this engine even where there is no fall, all the water raised by it being returned into the reservoir H H. There is, however, this de fect:—That as the surface of the water in the pipe becomes heated by the steam, and as it is impossible to form a perfect vacuum on the surface of boiling water, the effective power of the engine is by so much diminished. Nevertheless, it is a very simple, cheap, and serviceable machine.
To avert the loss which was consequent upon the escape of steam around the sides of the piston, to make the escape steam effectively available, and to reduce the consumption of fuel, Mr. Joss Roesnrsom, of Glasgow, contrived, and, in 1801, obtained a patent for, an engine which has, in practice, realized considerable portion of the inventor's expectations. It differs little in con
struction from many other engines, except that in place of one working cylin der in this, there are two, the lesser one n being placed upon and forming a continuation with the larger is. To each cylinder there is a piston fitted and connected together by the internal cylinder D: or this cylinder is so made as to have the pistons in one piece with it. This cylinder is made so that it may nearly fill the small cylinder ti, and without actual contact between the two surfaces. The working handles, with the valves, are to be placed in such a manner that steam from the boiler may have free access through the pipes and cylinders into the condensing vessel, to free the whole of the air, as in the usual manner. When this is done, the engine is set to work by the valves b and c being shut, and by that of a left open, and water let into the condensing ves sel c, when a vacuum takes place in it by means of the condensation of the steam, and also in the under part of the large cylinder m below its piston (there being a communication from the condensing vessel by the pipe F) ; at the same tame the steam from the boiler has free access through the pipe A and valve a into the small cylinder n, above its piston h, and exerts its force upon it, and presses it downwards with as much force as in the usual manner. But as it is found from experience that a considerable quantity escapes past the piston, this piston is in part detained by the secondary piston g, and exerts its force on that part or annular section s s that is contained betwixt the cylinders is and D, and assists in forcing the whole downwards; while, at the same time, the steam which in this annular space s s, and the cylinder D, prevents so great a quantity from escaping put the first piston, as would otherwise be the cue where there is no secondary ton, and the vacuum is much more complete below the first piston ; quently, there is a greater power duced from a smaller quantity of steam than with a single piston. During the time of the piston's descent, the valve a is shut, and the elasticity of the steam within the cylinders carries the pistons forward to near the bottom of these cylinders, when the valves b and c are opened by the handles and work, admitting the steam to pass from the upper sides of both pistons through the pipes B and E to the condensing vessel C, while the counter weight at the other end of the bum, or this nected with a fly-wheel, raises the tons again, when the valves b and c are shut, and that of a opened by the work, when the engine makes another stroke, as before. The piston-rod R joins the working-beam in any of the usual modes, and, in other respects, the engine is much the same as in common practice. The specification of this tent describes the ingenious furnace of this inventor. See article Fee ters.