Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

I've always been under the impression that routing the exhaust
back into the boiler is not a wise thing to do.  There is an
engine on German EBAY that does this, and it appears to be done
by one of the owners. What happens in this circumstance, besides
dropping the value?

www.ebay.de/itm/154512828772?hash=item23f9aea964:g:T7IAAOSwyGBgnPaX

Wayne

Gosh, I did not think of the counterpressure.  I was just thinking
of the boiler water becoming fouled w/cylinder oil.  I'd like to
see it steamed up - by someone else.

Wayne

  So, if I was to make a standing tank for the exhaust the oil will
stay on top (lighter than water?) and the relatively clean water
could be pumped back into the boiler and reused.  I presume the
feed pump would be crank driven and working all the time, like on
those old-timey German engines w/feed-pump I'm still waiting to score.
Ditto for a dynamo steam plant.

  Then again, I've never run an engine long enough for a function
like this to serve a purpose other than proving it works. 

Thanks for the replies,
Wayne

I think it's just the angle of the shot that is making it look like both lines are attached to the boiler. If you look at the 5th picture, in the upper right corner, it looks like the line from the side of the valve block ends just above the point where the other line is connected.

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Hello Paula,

you are right. Obviously some people here, including me, need one or a new pair of glasses.

  So, if I was to make a standing tank for the exhaust the oil will
stay on top (lighter than water?) and the relatively clean water
could be pumped back into the boiler and reused.  I presume the
feed pump would be crank driven and working all the time, like on
those old-timey German engines w/feed-pump I'm still waiting to score.
Ditto for a dynamo steam plant.

  Then again, I've never run an engine long enough for a function
like this to serve a purpose other than proving it works. 

Thanks for the replies,
Wayne

Hi Wayne, It doesn't always work this way with steam cylinder oil because it is designed to mix well with water and steam and thus will stay in suspension for a much longer time than regular motor or vegetable oil. It is great for the cylinder but not for the boiler.