On Sat, 16 Jul 2011 20:49:23 +0100, Clive wrote:

In message , Andy Breen
writes
The pet-cock,
Any similarity between this and the modern clack valve?

As I understand it, the pet-cock was for bleeding steam off from the
pump: "by opening (the pet-cock) the steam in the pump was let out, and
the action renewed" (Marshall, again).

I'd not expect a direct similiarity to anything on a "modern" steam engine,
as even the ones that use hot feed and pumps have the pump well away
from the boiler (and seals are much better, anyway)

--
From the Model M of Andy Breen, speaking only for himself