ENGINE, fire, by Rowntree. We have selected an engine by this maker to give a drawing and description, as it is greatly superior to the common engine with two force pumps. As that kind of engine has so often been described by various au thors, and its principles so essily compre hended from the description of a force pump, we judge it unnecessary to give any drawing pf it.
The fire engine by Rowntree is a dou ble force-pump, of a peculiar construc tion, similar in its action to the beer en gine, (described under that article,) but as it is on a much larger scale, its con structions, are of course varied. Plate Rowntree's engine, fig. 1 and 2, are two elevations at right angles to each other, of the external part of the engine mount ed on four wheels. Fig. 3 and 4, are two sections, perpendicular to each other, of the body of the engine or pump : fig. 5 and 6, are parts of the engine. The same letters are used as far as they apply in all the figures, A, A, A, A ; fig. 3 and 4, is a cast-iron cylinder truly bored ; it is ten inches diameter and fifteen long, it has a flanch at each end, whereon to screw two covers, with stuffing boxes, a, a, in their centres, through which the spindle, B, B, of the engine passes, and being tight packed with hemp round the collar, makes a tight joint ; the piston, H, is affixed to the spindle within the cylinder, and fits it tight all round by means of leathers, applied as described in the beer engine ; at E, fig. 4, a partition, called a saddle, is fixed in the cylinder, and fits against the back of the spindle tight by a leather.
We have now a cylinder divided by the saddle, E, and piston, into two parts, whose capacity can be increased and di minished by moving the piston, with pro per passages and valves to bring and con vey away the water : this will form a pump. These passages are cast in one piece with the cylinder : one, d, for bring ing the water, is square, and extends about -1 round the cylinder ; it connects at bottom with a pipe, e; at its two upper ends opens into two large chambers, f g, extending near the whole length of the cylinder, and closed by covers, h h, screwed on : i k, are square openings (shown by dotted squares in fig. 3.) in the cylinder, communicating with the cham bers f g, I m, are two valves, closing their ends of the curved passage, d, and preventing any water returning down the passage, d: n o, are two passages from the top of the cylinder, to convey away the water ; they come out in the top ofthe cylinder, which, together with the top of the chambers, f, g, form a large, flat sur face, and are covered by two valves, p q, to retain the water which has passed through them. A chamber, K, is screw ed over these valves : and, has the air vessel k, fig. 1 and 2, screwed into its top ; from each side of this chamber a pipe, c, w, proceeds, to which a hose is screwed, as shown in fig. 1. Levers, x x, Are fixed to the spindle at each end, as shown in fig. 1, and carry the handles,
H H, by which men work the engine. `When the piston moves, as shown by the .arrow in fig. 4, it produces a vacuum in chamber, f, and that part of the cylinder contiguous to it ; the water in the pipe, then opens the valve, m, and fills the cylinder. The same motion forces the water contained in the other part of the cylinder through the valve, q, into cham ber, K, and thence to the hose through the pipe, ; the piston being turned the -other way reverses the operation, with respect to the valves, though it continues the same in itself. The pipe, e, is screw ed by a flanch to an upright pipe, P, fig. 5, connected with another square iron pipe, fastened along the bottom of the chest of the engine : a curved brass tube, G, comes from this pipe, through the end of the chest, and is cut into a screw, to fit on the suction hose, when it can be used; at,other times a close cap is screw ed on, and another brass cap at H, within the chest, is screwed upwards on its socket, to open several small holes made in it, and allow the water to enter into the pipe ; in this case the engine chest must be kept full of water by buckets. The valves are made of brass, and turn upon hinges. The principal advantage of the engine is the facility with which it is cleaned from any sand, gravel, or other obstructions, which a fire-engine will al ways gather when at work.
The chambers, f, g, being so large, al low sufficient room to lodge a greater quantity of dirt than is likely to be accu mulated in the use of the engine at any one fire ; and if any of it accidently falls into the cylinder, it is gently lifted out again into the chambers by the piston, -without being any obstruction to its mo tion: to clear the engine from the dirt, two circular plates, r r, five inches diame ter, are unscrewed from the lids, h h, of the chambers/ g, and when cleaned are screwed on again : these screw covers fit perfectly tight without leather, and can be taken out, the engine cleared, and enclosed again in a very short time, even when the engine is in use, if found ne cessary.
The two upper valves, p q, and cham ber, K, can also be cleared with equal ease, by screwing out the air vessel, k k, fig. 1, which opens an aperture of five inches, and fits air-tight, without leather, when closed. The valves may be repair. ed through the same openings. The use of the air-vessel k k, fig. 1 and 2, is to equalize the jet from the engine during the short intermittence of motion at the return of the piston stroke : this it does by the elasticity of the compressed air within it, which forces the water out con tinually, though not supplied quite regu larly from the engine.
The engine from which our drawing was taken was made for the Sun Fire Insurance Company, in London, and from some experiments made by their agent, Mr. Samuel Hubert, appears to answer purpose.