. American engineer and railroad journal . attachment applied to one or both main steam cylin-ders of the locomotive, whereby they are made to compress airinto the main reservoir for temporary relief of the air bral<opump. The originator, Thomas Sweeney, is a locomotive en-gineer on the Southern Pacific, and his purpose was to pro-vide means for maintaining air pressure in the train pipe incase of failure of the air pump and in recharging when de-scending long mountain grades. The device consists of a pipe connecting the top or side ofthe steam chest with the main air reservoir, the passage
. American engineer and railroad journal . attachment applied to one or both main steam cylin-ders of the locomotive, whereby they are made to compress airinto the main reservoir for temporary relief of the air bral<opump. The originator, Thomas Sweeney, is a locomotive en-gineer on the Southern Pacific, and his purpose was to pro-vide means for maintaining air pressure in the train pipe incase of failure of the air pump and in recharging when de-scending long mountain grades. The device consists of a pipe connecting the top or side ofthe steam chest with the main air reservoir, the passage be-tween the two being controlled by a stop coclt at the steamchest and a check valve near the reservoir. A pop valve setto open at a pressure of 90 pounds, is mounted in the pipe andthe apparatus is completed by a connection from the stop cockand the cab, whereby the engineer may open or close it. When it is necessary to use the device, steam being shut reverse lever is placed slightly back of center notch and |! ^ liPipe iffBnPi, ?lFbp fa/rr 4 CutOutCoch. The Sweeney Air Compressor. the cylinder cocks left open for three or four revolutions ofthe engine to allow water that may be in the cylinders to es-cape; then the stop cock is opened and the brake valve placedin charging position. The reverse lever must be left back ofthe center notch at least fifteen seconds after full pressurehas been indicated on the air gauge. Before the reverse leveris moved forward the brake valve is placed on lap; and, in casethe air pump is not working, the stop cock should be closed,as the pistons will draw air from the main reservoir beforethe check valve closes. By placing the brake valve on the larand closing the stop cock before moving the reverse leverforward, sufficient pressure will be retained in the main reser-voir ot release the brake. After the cylinders have ceased towork as air compressors the brake valve should be left on thelap at least five seconds, so that t
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
