Max,

The use is possibly interesting if you understand it.

These and many other engines and turbines were used for a very simple
reason:
It is cheaper to make high pressure steam than low. This is a curious
aspect of steam, the transition for liquid to gas take fewer BTUs per
pound as pressure increases.

So- why not make high pressure steam and then let the pressure down
before you send it off to heat buildings?
- Good Idea -
If you try to simply reduct the pressure you end up with velocity
problems. But, if you use the steam in something and then exhaust it at
the desired presure and temperature, you just got the steam qaulity you
wanted and some mechanical work done for the price of the steam.

The reason engines like this were contracted well into the 20th century
is also simple:
Turbines Want Superheated Steam.
Superheat is when something is heated to greater than the saturated
temperature at that pressure (15psi heated to 250F 212).
This requires an extras part in the boiler (steam generator) called a
superheater (-duh) and makes the operation of the plant much more critical.
Reciprocating engines find little value in superheat.

If the engine runs a generator (like this one did) it can offset the
elecric load required for any large facility. One place I worked years
ago had two of these side by side. Was very much like the pictured
unit. The other had a directly conected air compressor.

Matt Colie - Again

Maxprop wrote:



This is strictly out of my bailiwick, Scott, but I am very curious--what are
such engines used for? What sort of installations? And where in the
Hoosier State did it go?

Max