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. 1863 Excerpt: ... Short pieces of pipe of different lengths are sometimes employed to connect the large end of the nose-pipe to the blast-pipe. They maintain the taper of the nose-pipe, but as their employment increases the number of joints for leakage, and causes obstructions to the free delivery of the blast, they should be, if ...
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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. 1863 Excerpt: ... Short pieces of pipe of different lengths are sometimes employed to connect the large end of the nose-pipe to the blast-pipe. They maintain the taper of the nose-pipe, but as their employment increases the number of joints for leakage, and causes obstructions to the free delivery of the blast, they should be, if possible, avoided. A better mode of adjusting the distance between the tuyere and fixed blast-pipe is by a telescope pipe properly fitted with a ring piston working air-tight in a cylinder, as delineated in PI. XV. Fig. 88, PL XXXII., Fig. 169. Pipes of this description have now been in use for several years at the Dowlais works, and for facility of working and economy of blast are probably unequalled. Their first cost is greater than the usual fixed pipe, but the numerous advantages which they possess amply compensate for the outlay. The breadth of the hearth should be considered in determining the taper of the nose-pipe, a wide hearth requiring less taper than a narrow one. With the old hearths the shape of the pipes was of less importance, as they were usually not more than 3 feet across. A pipe which would answer well for a hearth 3 feet wide, and supply sufficient air to all the fuel it held, would be totally unsuitable to one of 6 feet in width. The diameter of the nose is usually determined by the quantity of atmospheric air intended to be delivered, and with regard to the taper, from numerous observations, we are of opinion that for modern-sized hearths the large end should be one-fourth greater than the small for each foot in length. By this rule the outer end of a 4-inch nose-pipe, 18 inches long, would be 5J inches in diameter. If the metal in the end of the connecting pipe is very thick a socket should be made on the nose-pipe to go ove...
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