On Sun, 17 Jul 2011 19:11:47 +0100, Andy Champ wrote:

On 16/07/2011 13:09, Andy Breen wrote:

Use of vacuum as an important part of the working cycle wasn't banished
by Trevithick either: his most effective and longest-lasting engine
type, the Cornish mine engine, used high-pressure steam on one side of
the piston and vacuum on the other - made it a very efficient power
source for its day.


It's lasted a bit longer than that.

You know those big cooling towers on power stations? The turbine
exhaust is into a partial vacuum...


More assistive than providing 50% or so of the power output, though.

I did think of mentioning the use of condensers to assist the efficiency
and output of stationary and marine HP machinery, including turbines,
but decided not to as there seemed to be enough confusion about
the workings of simple pistons machinery...

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