. American engineer and railroad journal . ars in Fig. 4, reference beingmade to several letters. A corresponds to the extreme front end of travel, and at B thefull pri ssure is registered on the indicator at the end of the pipe,and the curve falls from the friction of rest to the friction of mo-tion. From G to D the valve becomes partly balanced by the por-tion overhanging steam port iV, and reduces the friction. From Dto £ port jV closes, the steam expands, reducing the balance, andthe friction rises slightly. From £^ to F the steam in port N ex-pands more, slightly increasing the friction.
. American engineer and railroad journal . ars in Fig. 4, reference beingmade to several letters. A corresponds to the extreme front end of travel, and at B thefull pri ssure is registered on the indicator at the end of the pipe,and the curve falls from the friction of rest to the friction of mo-tion. From G to D the valve becomes partly balanced by the por-tion overhanging steam port iV, and reduces the friction. From Dto £ port jV closes, the steam expands, reducing the balance, andthe friction rises slightly. From £^ to F the steam in port N ex-pands more, slightly increasing the friction. From F to O com-pression begins in port 31, increasing the balance and diminishingthe friction slightly. From O to // the steam in port N is ex-hausted, diminishing the balance and increasing the friction. Fromi?to /the admission of steam in port M increases the balance andthe friction drops, and from / to ./ the valve moves from off port Afand the friction increases. From J to K, the end of travel, theconditions remain nearly Plate from Dynamometer. It would require too much time and space to thus analyze all thediagrams, but those who wish to s^udy the effects closely can pro-ceed as indicated above. The committee found it was unable to determine the stuffing-boxfriction, but this would probably be constant. It is found that theunbalanced valve requires twice as much work to move it as thebalanced valves, and your committee believer that this will repre-sent the average results in ordinary railroad practice. Of course,by balancing a large area, the friction could be still further re-duced, but the danger of the valves lifting off its seat would berather great. Your committee, therefore, recommends thefolow-ing rule for balancing slide valves : Area of balance = area of exhaust port + area of two bridges +area of one steam port. The above is to obtain tor both Allen and plain valves. Your committee had hoped to be able to give the results of someexperi
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
