On Sun, 17 Jul 2011 17:49:27 +0100, Charles Ellson wrote:

On Sun, 17 Jul 2011 16:25:57 +0000 (UTC), Andy Breen
wrote:

On Sun, 17 Jul 2011 17:15:30 +0100, Charles Ellson wrote:

On Sun, 17 Jul 2011 08:48:47 -0700 (PDT), harry
wrote:

On Jul 17, 4:23Â*pm, Charles Ellson wrote:
On Sat, 16 Jul 2011 23:28:13 -0700 (PDT), harry
wrote:

On Jul 16, 9:27Â*pm, Andy Dingley wrote:
On Jul 16, 7:07Â*pm, harry wrote:

The staem was used to flush air out of the cylinders.

Er no, the air was displaced by the steam being fed into the
cylinder. Get your intentions and consequences in the right order.

So where exactly is the diffence?

"Flushing" is generally the deliberate rather than consequential
purging of a substance from somewhere. If you are referring to the
animation at the top of the above Wonkypaedia article then no such
process is shown but if any does take place then it will (except at
startup) be "expired" steam that is flushed rather than air.

Opening a valve to admit steam to the cylinder seems deliberate enough
to me.

It's fairly clear from his own writings that Mr Savery was of the same
opinion:

"Then skrew in the faid pipes again as tight as possible. Then lightthe
fire at B No.1. When the water in L boyles, the handle of the regulator
mark'd Z, must be thrust from you as far as it will go, which makes all
the steam rifting from the water in L, pass with irriftible force
through O No.1 into P No.1 pushing out all the air before it, through
the clack R No.1 making a noise as it goes."

'The Miner's Friend, or, An Engine To Raise Water By Fire', Thomas
Savery, S. Crouch, 1702, available on-line at:

http://library.thinkquest.org/C00601...am%2Fsavery%2F

To me, that implies a very deliberate use of the steam to flush out the
air in the working vessel..

That device looks distinctly different to the one in the Wikipaedia
article.

What? Counting on Wikipedia as an authority here?

Rather than using a piston it seems to use alternative positive
and negative pressure (relative to atmosphere) in a vessel with valves
arranged so that water is sucked in from below then discharged up to the

Yes. Newcomen's engine was essentially a combination of ideas from
Papin (piston-in-cylinder) and Savery (use of condensation of steam
to create a vacuum to raise water). The working principles, in
terms of the use of steam to expel the air from the working vessel
and then condensation to provide the working force, however, were
the same as Newcomen's machine - a fact recognised by Newcomen
himself, as he conceded that his machine was covered by Savery's
patent (the small number of Newcomen engines installed before
the expiry of Savery's patent was a result of this - the patent
royalties made them even more expensive).

surface. As often occurs, older descriptions can be somewhat simplistic;
the purpose is clearly to propel water while any propulsion of air is
consequential to some being present but not necessary for the ongoing
process.

The text clearly shows that Savery understood that his engine worked
by replacing the air in the working vessel with steam which could then
be condensed to create a vacuum, with the latter being used to raise
water (exactly the same principle as was adopted to a cylinder/piston
and separate boiler by Newcomen).

Maintaining otherwise shows a disregard for primary evidence which
surprises me in your case (I'd expect it from Michael, or Bruce
in recent years, but not you).

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