Identifier: diseasesofairbra00synn (find matches)
Title: Diseases of the air brake system; their causes, symptoms and cure
Year: 1894 (1890s)
Authors: Synnestvedt, Paul
Subjects: Air-brakes
Publisher: Chicago, The W. F. Hall Printing Company
Contributing Library: Northeastern University, Snell Library
Digitizing Sponsor: Northeastern University, Snell Library

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em by the trainmen. Equalizing Valve of 1888. Plate 28 is taken from Westinghouse temporary cata-logue for 1888, plate C. 7, and was about the first formof the present equalizing valve put into service. Mostof those sent out have since been removed, so that, notso much with a view to practical usefulness, as in thelight of an item of interest, we here insert a few wordsconcerning it. It differed from the later style in the arrangement forpermitting the air, in the release of the brakes, to passto the train pipe directly through the equalizing piston,the ports (shown in the plate) being closed after equal-ization, by the cup valve 20, held to its seat by thespring 17. The main difficulty v/ith this arrangementwas that, if from any dirt or imperfection, the valve 20failed to seat properly, whatever pressure was reducedfrom the cavity above the piston in service applicationswas supplied by air leaking back from the train pipe, theequalizing valve therefore failing to open. PUMP GOVERNOR.
Text Appearing After Image:
(104) Plate 29. Diseases of the Air Brake System. 105 One noticeable thing about this valve was that on shorttrains it did not blow from the service exhaust when thehandle was thrown to release position, the reason forwhich will be obvious on a moments study. Old Style Governor. Plate 29 is a sectional view of a pump governor manyhundred of which are still in use, and which for conven-ience we shall call the Old Style Governor. Theywere never ver)^ satisfactory, and in fact, but very few ofthose coming under the writers personal observationwere of any value at all. They were defective in theoryand consequently a total failure in practice. The major-ity of them never would stop the pump at all. In oper-ation they depended to a certain extent on back pressurefrom the pump, acting upwards on valve 10, and of courseas soon as this back pressure disappeared, nothingremained to hold valve 10 shut» It seems reasonable to suppose that if a good stiffspring were substituted for the spindle 9

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