Martin Evans Midland Single

In the Martin Evans Midland single there are 2 injectors, one of which has a combined clack for both the injector and the pump.

The drawings give no dimensions.

Does anyone have dimensions for this?

Brian

For "Princess of Wales" Martin Evans gives the dimensions of 2 clacks for the boiler backhead. They're on p436 of ME 7th. May 1971. There's nothing else AFAIK apart from 2 injector steam valves shown on the steam manfold. I don't recall any mention at all of a pump, builders are on their own. I'm not quite that far with my build.

Many thanks for the reply Clive, If I find any further information I'll be sure to let you know. I'm just wondering how the boiler is filled before a steam-up.

Brian

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Hello Bill, I've only just seen your reply and I'm sure you are right but this isn't my engine. Martin Evans mentions a drawing but says that he is not going to describe it as he has done it many times before and that's the problem; trying to find where he described it before.

As I understand it, there is a combined clack on the boiler for a hand pump and injector and the engine builder would like a drawing so that he can make it.

Brian

I've just re-read Martin Evans build notes. As said, he mentions providing a drawing but doesn't do so. However, googling "double clack" produced a thread on this forum with an outline design which should be useful here

Too late to edit my post above, but Martin Evans does show a pipework sketch with a double check valve separate from the boiler clack. This implies that the injector has to feed through two check valves in series, which might not be a good thing. The appearance of the backhead would be more "scale" though.

There is no detail in the Evans sketch and I'm not aware of any published design for a double check valve that is not boiler mounted and would suit this arrangement.

Edited By Clive Brown 1 on 05/02/2022 11:16:10

Many thanks Clive, I've passed the details on to the builder.

I've been trying to find out details of the check valve that Martin Evans says he is not going to describe on the grounds that he had described them many times before.

Brian