Injector Water Supply Valves

[Fender]

My mogul has two injectors, which are mounted low per common practice. The normal operating procedure is to open the water supply valve on the tender, then open the steam valve to the injector, then throttle the supply valve to stop water from coming from the overflow. Shutting off the injector requires closing the steam valve, then closing the supply valve on the tender. If a guest engineer forgets this last step, then water continues flowing out the overflow, until the tender tank is empty (of course, I would NEVER make this mistake myself ).
This got me thinking about putting a steam-actuated valve in the water supply line upstream from the injector. This would need to be a normally-closed valve with a pneumatic actuator. When the steam valve to the injector is opened, it would also feed the actuator to the water valve (via a syphon to prevent steam from getting into the actuator) thus opening the valve. When the steam valve is closed, the water valve would also close, stopping the overflow. The water valve on the tender could be left open.
Has anyone tried something like this? Clippard
Offers a number of inexpensive normally-closed two-way valves and compatible actuators.

[SZuiderveen]

Dick Bagley published a design for a one lever injector in Live Steam, December 1983. This shot is from my bound volume. If you cannot find it at home, I will have to find a loose copy to properly scan the “gutter.”

Steve

[Berkman]

Keep in mind many times you need to throttle the water going into the injector.
Also independent water control is nice to be able to cool the injector down if needed.

A floor mounted lever control valve would be cool though for water control. Take a like by the engineer seat of many steam locomotives.

[Fender]

Agree that the water needs to be regulated (throttled) and this setting varies somewhat depending on boiler steam pressure. But, if there is a separate shutoff valve from the regulating valve, and the engineer can maintain a consistent boiler pressure, then the regulating valve could usually be left alone. I have one Ohlenkamp and one Superscale injector, and they are both very reliable.

[Soot n' Cinders]

Just mount the injector in the lifting position with a vacuum breaker on the overflow! Works great on the shay. When over 100psi in the boiler, all I have to do is hit the steam and off it goes. I leave the water valve fully open unless the boiler pressure gets under 100, then the water supply needs throttling. But being in the lifting position, water stops flowing when the injector stops sucking.