. The science of railways . ing valve, with the latter inthe position when the engine is either startingor being run as a single-expansion 183 shows the same section with the inter-cepting valve in compound position. R is thereceiver port; *S is a connection from the mainsteam pipe; L is a port leading to the low-press-ure steam chest, and i? is a reducing valve. Theintercepting valve is composed of the four pistons,1, 2, 3 and 4, of which the last works in an oildash-pot C. 580 vol 12 297 298 ENGINEERS AND FIREMENS MANUAL. If the engine had stopped after running com-pound with
. The science of railways . ing valve, with the latter inthe position when the engine is either startingor being run as a single-expansion 183 shows the same section with the inter-cepting valve in compound position. R is thereceiver port; *S is a connection from the mainsteam pipe; L is a port leading to the low-press-ure steam chest, and i? is a reducing valve. Theintercepting valve is composed of the four pistons,1, 2, 3 and 4, of which the last works in an oildash-pot C. 580 vol 12 297 298 ENGINEERS AND FIREMENS MANUAL. If the engine had stopped after running com-pound with the valve, as in Fig. 183, and the en-gine throttle were then opened, live steam fromthe pipe S would force the intercepting valveinto simple position as shown in Fig. 182, becausepiston 2 is larger than piston L In this latterposition small port D is open and steam from Spasses through it and the reducing valve B tothe low-pressure side. Piston 3 has now closed thecommunication with the receiver R in which one ^^^^s^^^^ss. or two exhausts from the high-pressure cylindersoon produces sufficient pressure to react on thispiston 3, bearing the intercepting valve to theleft against the differential pressures on pistons1 and 2 acting in the opposite direction, and thevalve is shifted to compound position, as in , in which position no more live steam canpass through port D to the low-pressure side, and OPERATION OF COMPOUND LOCOMOTIVES. 299 the receiver R is connected through port L withthe low-pressure steam chest, for which it formsthe supply thereafter, as indicated by the arrows. The port leading from the live steam supi^ly Sinto the intercepting valve, is larger than itappears from the illuvStrations, as it extends partlyaround the circumference of the valve. The separate exhaust valve shown in Figs. 184and 185 is placed on the receiver m the smoke- m s^ h >V^T^i777^
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectrailroa, bookyear1900
