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Rotary Valve. Release Position
Copyright, 1909, by The Norman W. Henley Publishing Co.
Fig. 35.—S-6 Independent Brake-Valve. Top view of transparent
rotary valve, and plan view of rotary-valve seat. Release posi-
ent application is made. The long, radial groove, g, in the face of the rotary valve is now connecting the "application-cylinder” port in the seat with the atmospheric exhaust-port h in the center of the valve seat,
thus discharging the pressure from the application cylinder of the distributing valve at the independent brake-valve, and releasing the locomotive brake under any circumstances of its application, regardless of the position of the automatic brake-valve handle. The small “warning port” through the rotary valve is now in register with the similarly designated port in the seat, providing a slight discharge of reducing-valve pressure to the atmosphere, the noise from which serves to warn the engineer that the independent brake-valve is in a position in which the locomotive brake would immediately release after any manner of automatic application; the warning feature acting as a safeguard in case the return spring should become broken.
It will be noticed that the route of the distributingvalve release pipe from distributing valve to automatic brake-valve is broken in this position, by the separation of the two ports in the seat indicated as the independent brake-valve terminals of the piping—the sections leading to distributing valve, and automatic brake-valve, respectively.
In Fig. 36 the return spring has rotated the INDEPENDENT BRAKE-VALVE to Running Position; in this, the second operative position, ports e in the rotary valve, and b in the seat, are still in connection to provide the supply of reducing-valve pressure above the rotary
Rotary Valve. Running Position
valve; but the "application-cylinder” port and “warning port” in the seat are now blanked under the face of the rotary valve.
No positive work is performed by the independent
Fig. 36.-S-6 Independent Brake-Valve. Top view of transparent
rotary valve, and plan view of rotary-valve seat. Running position.
brake-valve in this position; in ordinary switching : service it is used to release the locomotive brake, but this is not positive, and depends upon the automatic brake-valve also being in running position. It is the
regular carrying position of the handle, featured as the only position in which the distributing-valve release pipe has an open route through the independent brake-valve to the automatic brake-valve, the channel, f, in the face of the rotary valve of the former now connecting the two ports in the seat leading, as indicated, to the two sections of the pipe running to the distributing valve, and automatic brake-valve, respectively. As it is only through this port connection that locomotive-brake release can occur when the automatic brake-valve is placed in running position, it is very important that the independent brake-valve shall be carried in running position, always, when not being used.
It is apparent that the INDEPENDENT BRAKE-VALVE can release the locomotive brake in one position under any circumstances, and in two positions when the automatic brake-valve is in running position; in the latter case, after an independent application the return of the independent brake-valve to running position permits the application-cylinder pressure—which at that time is in the distributing-valve release pipe as far as the INDEPENDENT BRAKE-VALVE—to pass through the continuation of that pipe to the automatic brake-valve, and through its rotary valve to the atmosphere; brakecylinder pressure being equally discharged at the exhaust port of the distributing valve. The third position of the INDEPENDENT BRAKE
VALVE is Lap, as represented in Fig. 37. This is a negative position, in which all ports are closed-except, of course, the ports for the reception and passage of reducing-valve pressure to the top of the rotary valve.
Fig. 37.—S-6 Independent Brake-Valve. Top view of transparent
rotary valve, and plan view of rotary-valve seat. Lap position.
The distributing-valve release pipe is again cut off and blanked at the rotary valve, by the switching of the groove, f, in the face of the rotary away from the port "to automatic brake-valve' in the seat.