A practical treatise on high pressure steam boilers; including results of recent experimental tests of boiler materials, with a description of ... injectors and economizers in actual use

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. 1880 Excerpt: ...Boilers--Arrangement and number of Tubes--Proportions for Shells--Grate Area--Coal required per hour--Tube Area--Evaporative Power of Tubular Boilers--Compound Tubular Boiler. Externally fired boilers--The simplest form of a boiler is a plain cylinder set in brick work. This type of boiler is largely used in sections of the country where coal is cheap, or in the lumber regions, where sawdust and slabs are used as fuel. In many cases where fuel is abundant and cheap, the feed water hard and apt to form a troublesome scale, cylinder boilers recommend themselves as being at once easily managed, easily cleaned, offering, with the exception of the sphere, the strongest possible form to resist bursting, and affording the readiest facility for examination and repairs; and, for a given weight or efficiency of heating surface, the lowest priced boiler that is now in the market. These boilers steam well, and prime less than any other form. In mining and lumber regions they are especial favorites, and it would be difficult to displace them, especially if the feed water is impure. They are also extensively used at blast furnaces, and less so, perhaps, in rolling mills. An argument used against externally iired boilers is, that the plates immediately over the furnace arc liable to become overheated either by too hard firing or by the accumulation of scale in the boiler; the pressure being internal, the tendency to rupture being that of bursting. The plates are none too strong to begin with, and being further weakened by overheating they become dangerous iu the extreme, and are thus liable to explode at any time when overworked. There ia much of a showing of truth in the statement, but fortunately it has not been verified in actual experience. That explosions of exernall...