Clack Valve

Spencer Sutton asked "Whereabouts is the Clack Valve and what is it used for ?"

Good question. I had to go and look up the answer to this as while I've heard of a clack valve, it's exact purpose hasn't been that important to me. The answer can be found on here.

Essentially the clack valve is part of the injector and normally found on the backhead (the back of the boiler/firebox, above the door coal is shovelled into) of a steam engine. Operated by the fireman (normally) the injector allows water from the tanks or tender into the boiler. The clack valve is a non-return valve that makes sure water only flows one way.

The name by the way, comes from the noise the valve makes when operating.