. Locomotive text for engineers and firemen; a complete treatise on the engine, electric head-light and standard code of train rules . arting valve open andreverse lever down. Then open the cylinder cocks anda<imit steam, and move the engine slowly. Note the cross- 276 COMPOUND LOCOMOTIVES. head as it nears the end of its stroke, and if steam is ad-mitted too early for that end of cylinder it indicates thatring No. 5 or 6 is broken. When either No. 7 or 8 valve ring is broken, it willcause a blow just before the exhaust takes place, and willalso cause a light and early exhaust. This can be
. Locomotive text for engineers and firemen; a complete treatise on the engine, electric head-light and standard code of train rules . arting valve open andreverse lever down. Then open the cylinder cocks anda<imit steam, and move the engine slowly. Note the cross- 276 COMPOUND LOCOMOTIVES. head as it nears the end of its stroke, and if steam is ad-mitted too early for that end of cylinder it indicates thatring No. 5 or 6 is broken. When either No. 7 or 8 valve ring is broken, it willcause a blow just before the exhaust takes place, and willalso cause a light and early exhaust. This can be deter-mined by watching the crosshead and noting from whichend of the cylinder the light exhaust comes. A broken admission ring No. 1 or 2 in the high pres-sure valve gives too early a port opening to the highpressure cylinder and cuts off the steam too late. Thisallows too much steam to be admitted to the high pressurecylinder and when the steam is exhausted to the atmos-phere it will be indicated by a heavy exhaust. Plate 126shows a sectional view of the valve placed centrally onits seat and the arrangement of the ports. fidfl. PLATE 126. When testing for a valve blow in a tandem compound,the engine should be placed on the quarter, the brake set,the ports covered, the cylinder cocks on the high pressurecylinder blocked open, and the engine given a full headof steam. If no steam appears at the cylinder cocks itindicates that the two admission rings are in good con- COMPOUND LOCOMOTIVES. 277 dition. If, however, the steam blows out of either orboth cylinder cocks, it indicates that the rings are leakingor broken. To test the low pressure valves, the startingvalve should be opened, the cylinder cocks on the lowpressure cylinder opened and steam admitted. If thereis a blow past the inside admission rings, it will show atthe cylinder cocks. If the valve has exhaust clearanceit will also blow to the stack. The cylinder cock fromwhich the steam appears indicates the end of the valve
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