. American engineer and railroad journal . Fourteenth. Double nozzles should be located with reference tothe stack tbe same as single nozzles. Conclusions from the Von Borries-Troske tests (see AmericanEngineer, Car Bdilder and Railroad Journal for March andMay, 1896) on the effect of various lengths of conical and cylindri-cal stacks. Fifteenth. The maximum height of stack, measured from the ex-haust nozzle, if the diameter at the choke is properly chosen, neednot exceed five times this diameter. For cylindrical stacks theratio of diameter to height is the same. SUcteenth. The vacuum increase
. American engineer and railroad journal . Fourteenth. Double nozzles should be located with reference tothe stack tbe same as single nozzles. Conclusions from the Von Borries-Troske tests (see AmericanEngineer, Car Bdilder and Railroad Journal for March andMay, 1896) on the effect of various lengths of conical and cylindri-cal stacks. Fifteenth. The maximum height of stack, measured from the ex-haust nozzle, if the diameter at the choke is properly chosen, neednot exceed five times this diameter. For cylindrical stacks theratio of diameter to height is the same. SUcteenth. The vacuum increases as the stack is shortened andmore rapidly with cylindrical than with conical stacks. Seventeenth. The decrease in vacuum due to shortening tbestack within certain limits can be nearly overcome by lowering thenozzle. The amount which the nozzle should be lowered withcylindrical stacks is almost equal to the amount the stack is short-ened. With conical stacks the nozzle should be lowered abouttwo-thirds as much as the stack is Plate - Plate 48 shows the arrangement of exhaust pipe, nozzle, petticoatpipe and stack, which gave the best general results as to vacuumand efficiency in the committees tests. An inspection of the re-sults of the tests in Part II. will show that certain variations fromthe above change but slightly the effectiveness of the draft appli-ance. The limits within which the different parts experimentedwith can be changed without materially affecting the efficiency ofthe apparatus as a whole are as follows: First. Height of the bridge should not be lower than that shown,although lowering it decreases the efficiency but little. Second. Distance of the nozzle from the choke of the stack canbe from 49 inches to 39 inches, preferably nearer the former thanthe latter. Third. The area of each opening at the choke of pipe can be de-creased below the area of the nozzle as much as 20 per cent., with-out greatly decreasing the efficiency at speeds and cut-offs
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
