Compound Beam Engine

Down in Taunton last week, we found this beam engine in the museum. It had been used to power a local silk mill.

I have not seen a twin cylinder, compound beam engine before. The high pressure cylinder has both a smaller diameter and stroke, compared with the low pressure cylinder. If I didn't have 20 other projects on the go, it looks like a good subject for a model.

Some of the Cornish Tin Mines used compounds for pumping, although, by modern standards, ,pressures were low.

James Watt used his patents to keep a hold, on engines in Cornwall, and elsewhere.

It was Richard Trevithick who believed in using "Strong steam" ( 40 psi vs Watts 5 psi ), so compounding would have greater benefits with higher pressures.Wolff was an exponent of compounding, in Cornwall mine engines.

Howard

There are a few of the Woolf compounds about, Preston's has one if I remember rightly.

More about this one on Grace's

Another one at the London Museum of Water and Steam near Kew Bridge.

Handy for us in the region!

Easton & Amos

Edited By V8Eng on 03/08/2022 18:46:48

Thanks for the link, Jason. I was not aware of that web site. Seems the compound beam engine was more common than I thought!

Bolton steam museum have at least one.

A better method of adding a HP cylinder to a beam engine is to put it at the crank side of the beam pivot as in McNaught engines. This reduces the bending load in the beam compared with both the same side. A lot of one cylinder beam engines were retrofitted with a second HP cylinder .

Not forgetting this lovely example of an Easton and Anderson compound at the Forncett Steam Museum.

Always thought this would make for a lovely model project too

Bit late in the day for me now though

Tug

The pumping engine at Western Springs in Auckland NZ is a compound. It actually has four cylinders and two beams, all connected to a single flywheel with a crank on each side. The HP bore and stroke are smaller than the LP, as with the engines above. Two pumps were driven, one from each beam.

The Hamilton beam engines in Hamilton Ontario are similar, except that there are two flywheels, making two separate engines with two cylinders each. Another difference is that the Hamilton engines have Watt's parallel motion where the Auckland engine has slides.

Actually once each cylinder would have been referred to as an engine, I'm not sure when that would have changed. The Hamilton engines are 1857-59, the Western Springs one was 1860's

John