The Science and Art of the Manufacture of Portland Cement; With Observations on Some of Its Constructive Applications (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. 1877 Excerpt: ...and receives a series of frequently recurring blows from the revolving blocks, and when reduced sufficiently passes out at apertures in the side of the tub or casing. This machine is costly in character, and was represented as competent to reduce gold quartz to the size of coarse gravel at the rate of 200 tons in twenty-four hours. The size or quality of the products from this machine was capable of regulation by the form and extent of the perforations at the circumference of the casing. The machine was a complicated one, and if metal could have been procured durable enough to withstand the shock and concussion of a so violently propelled mass of metal, its success might have been secured. The result, however, of all this ingenuity was that the machine, while reducing minerals, could not prevent its own degradation, which became so great as practically to render it useless. The " Carr's Disintegrator," in use for reducing minerals of various kinds, and even grain, obtains its value from the violence of the action produced by bars revolving in opposite directions, against and between which the materials under treatment are forced, coming also into contact with each other, the high speed of this machine, as well as the American one, producing draught or ventilation, thus expelling the finely comminuted particles as they become small enough to pass out. This class of machine is not, however, reliable enough for cement-making purposes, and the high speed at which they must of necessity be driven incurs liability to accidents accompanied by excessive wear and tear. What the cement maker requires is a machine competent to perform in a united shape the work of a "breaker," "crusher," and "grinder," and the author feels assur...