Steam; Its Generation and Use with Catalogue of the Manufactures of the Babcock and Wilcox Company (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. 1902 Excerpt: ...horse-power, is a fair one for both boilers and engines, and has been favorably received by the Am. Soc. of Mech. Engineers and by steam users, but as the same boiler may be made to do more or less work with less or greater economy, it should be also required that the rating of a boiler be based on the amount of water it will evaporate at a high economical rate. For purposes of economy the amount of heating surface should never be less than one, and generally not more than two, square feet, for each 5,000 British thermal units to be absorbed per hour, though this depends somewhat on the character and location of such surface. The range given above is believed to be sufficient to allow for the different conditions in practice, though a far greater range is frequently employed. As, for instance, in torpedo boats, where everything is sacrificed to lightness and power, the heating surface is sometimes made to absorb 12,000 to 15,000 B.T.U. per square foot per hour, while in some mills, where the proprietor and his advisers have gone on the principle that "too much is just enough," a square foot is only required to absorb 1000 units or less per hour. Neither extreme is good economy. Square feet of heating surface is no criterion as between different styles of boilers--a square foot under some circumstances being many times as efficient as in others; but when an average rate of evaporation per square foot for any given boiler has been fixed upon by experiment, there is no more convenient way of rating the power of others of the same style. The following table gives an approximate list of square feet of heating surface per H. P. in different styles of boilers, and various other data for comparison: --HORSE-POWER OF DIFFERENT NATIONS. Most nations have a s...