Transactions . etected. The glass does not become coated with dirt, likemica. Since good running of furnaces is shown by a bright tuyere,it is necessary to have a good eye-piece to examine them. To detach the pipe, a man lifts the weights, the side rods are thenslipped off the bell crank under the quarter turn, the link under thebelly-pipe is unhooked, and the pipe carried away. The same pro-cess is reversed to put the pipe together. The nozzle is changed by taking off the cap, G, drawing the noz-zle through the belly-pipe, and inserting another. In this way thechange can be made quickly, with
Transactions . etected. The glass does not become coated with dirt, likemica. Since good running of furnaces is shown by a bright tuyere,it is necessary to have a good eye-piece to examine them. To detach the pipe, a man lifts the weights, the side rods are thenslipped off the bell crank under the quarter turn, the link under thebelly-pipe is unhooked, and the pipe carried away. The same pro-cess is reversed to put the pipe together. The nozzle is changed by taking off the cap, G, drawing the noz-zle through the belly-pipe, and inserting another. In this way thechange can be made quickly, without taking down the pipe. On the old tuyere pipe bolts with brass nuts were used, Avhichburned up and gave trouble. In other cases key-bolts were used,making it difficult to adjust the pipe. Bolts make too rigid a joint, and there is no provision for move-ment from contraction or expansion. As the temperature of theblast increases there is more expansion, and where rigid joints are IMPROVED PIPE AND TUYERE. 163. 164 IMPROVED PIPE AND TUYERE. used they must be eased up, or leakage will start at some otherpoint. What is required is sufficient force to hold the joints to-gether and have them flexible and yielding at the same time. Therods and levers give this flexibility to the pipe, dispense with thebolts, and allow for expansion. After two years trial this system of lev^ers and links for holdingthe pipe together has been found to do well. It especially recom-mends itself for quickness in taking down and putting up the pipe. The loss from transmission and radiation of tuyere-pipe has re-ceived but little attention. Take the case of the old tuyere-pipe,which averaged 11 square feet of surface, used in connection with a4-inch nozzle. This would deliver 1700 feet of air per minute, sayat 1200°, with a total loss of heat of 8 per cent. This loss, in thecase of the new pipe, is 3J per cent., and the difference between thetwo represents a loss of 105 tons of coal per year for a 17-foo
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
