Triple expansion engine

A triple expansion engine, reputedly built by the eminent engineer Professor Sir Charles Inglis.

Rarer than their marine cousins, non-reversing triple expansion engines were built for applications such as pumping and generating, where the high efficiency of compounding was required but the engines were only ever required to run in one direction.

An imposing size model, nearly two feet long on its base, it weighs just over half a hundredweight.

Like many models of this age - we suspect it's coming up to ninety years old or more - there appears to have been more than one hand involved in its build.

The bottom end is very finely constructed, with one-piece crank - a fine, intricate piece of turning - and elegantly proportioned connecting rods, Machining is very crisp, the bearing caps, crossheads and guides fitted with a good deal of precision - the engine turns over without tight spots.

The two high pressure cylinders are complete with pistons and piston valves - the low pressure cylinder has piston but is missing the slide valve. Top covers are marked for orientation. There is small part of the low pressure cylinder casting broken at the top of the steam passage as it enters the bore, we suspect not big enough to affect running,

The condenser, fabricated in brass, requires innards and end covers. There is a bag of loose wooden cylinder cladding - not complete, but enough to serve as a pattern, giving an idea of what was in the builder's mind.

An interesting project - it would be wonderful, after so long in gestation, to see this one run.

Professor Sir Charles Inglis O.B.E., M.A., LL.D., Hon.M.I.Mech.E., F.R.S., 1875-1952

Professor Inglis was an eminent civil engineer - a Fellow of the Royal Society, he was associated with the Institutions of Mechanical, Civil and Waterworks Engineers respectively during his working life. He sat on the board of inquiry into the loss of the R101 airship and was chairman of the post-war railway modernisation committee.

He spent his later years developing theories on the education of engineers, writing a textbook on Applied Mechanics, a copy of which is included with the engine.

Described as the greatest teacher of engineering of his time, from 1919 to 1943 he was Professor of Mechanical Sciences at Cambridge University, the Engineering Department's Inglis Building there named in his honour.

Professor Inglis had a pragmatic approach to engineering problem solving, one not requiring learning for learning's sake.

As he so eloquently stated:

"Mathematics [required by engineers] though it must be sound and incisive as far as goes, need not be of that artistic and exalted quality which calls for the mentality of the real mathematician. It can be termed mathematics of the tin-opening variety, and in contrast to real mathematicians, engineers are more interested in the contents of the tin than in the elegance of the tin-opener employed."