The Book of Trades, Or, Circle of the Useful Arts (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1846 Excerpt: ...descends into the cistern, and is terminated with a valve v. The apparatus is so adjusted, that this valve is always close when the water is at the proper height in the boiler; but whenever the water gets in the least degree below the requisite level, the float P sinks, and by raising the opposite arm of the lever, opens the valve at the bottom of the cistern, and the deficiency is immediately supplied by the water trickling down through the pipe which proceeds from the bottom of the cistern into the boiler. In short, so nice is the adjustment, that the water proceeds into the boiler precisely at the rate necessary to compensate for the waste. A second important appendage of the steam engine is the selfregulating damper. A damper is a sliding iron plate, applied to a flue or chimney, in order to regulate its draught and govern the intensity of the fire. The damper commonly employed in connexion with the steam engine is selfregulating, and we shall endeavour to explain how it is rendered so. In the adjoining figure D is an iron plate sufficient in size entirely to close the flue E. This iron plate, or damper, is connected with the weight p, by means of a chain passing over the two pulleys p p. The weight t is made a little heavier than the damper, so that when the engine is not at work, the damper will always be drawn up, leaving the flue quite open. But whenever steam is generated in the boiler, it will press on the surface of the water there, and force it up the tube to the weight F, which, thus becoming immersed in water, is buoyed up, and the damper will descend more or less according to the force of the steam, and thus check the intensity of the Are. If the steam becomes weaker than required, the water in the pipe descends, and along with it the weight ...