The design and drawings were produced by the late Arnold Throp C. Eng., M.I.Mech. E. who served as an apprentice with Cole Marchent & Morley, a Bradford firm of engine builders who in their day turned out amongst others, Corliss valve engines. George Corliss had his works in Rhode Island U.S.A and this type of valve became very popular with engine builders not only in America but in Europe due to its capability of a very fine speed control required for spinning. They lasted till the end of steam. They ranged from a single cylinder to triples and twin tandem compounds and from quite small powers up to 3000 H.P.
Fortunately there are a number of these engines that have been preserved and can be seen in steam. One of the features of this valve is that most builders used their own design of trip gear, often patented, which of course is controlled by the governor. The engines rarely ran much over 90 R.P.M. due to the limitations of this trip gear. “A mechanism as beautiful as a human hand releases or retains its grasp of the feeding valve, and gives a greater or lesser dose of steam in nice proportion to each varying want’ Scott Russell reporting on the Paris Exposition of 1867. There are a number of examples of Corliss engines in preservation and in occasional steam in the country:- the London & Manchester science museums; Bancroft Mill at Barnoldswick; Coldharbour Mill at Uffculme, Devon; Mill Meece, Staffs.; Ellenroad Mill, Milnrow, by exit 21 on the M62, Markham Grange Nurseries, Brodsworth, Doncaster (steamed every Wednesday) to name a few.
Arnold Throp described his engine, though not the making of it, in the Model Engineer of the second issues of August and September 1982. It is thought that this engine is now in a museum in Australia.
It is a reasonably large model, so the trip valve gear is capable of working, often a fault on model Corliss valve engines. Typical of the medium size engines the flywheel is cast in two halves and bolted together, also typical of the type the barring rack is cast in on one side of the wheel. We are supplying the following cylinder arrangements:
(Finished size, less air pump.)
|Single cylinder Corliss||21 in.||11 in.|
|Tandem Compound, HP Corliss & LP slide valve.||26 in.||12 in.|
|Cross Compound, HP Corliss & LP slide valve||21 in.||16 in.|
|Twin Tandem Compound, 2 x HP Corliss 2 x LP slide valve (The castings with this engine include two flywheels)||26 in.||19 in.|
|Cross Compound all Corliss||21 in.||17 in.|
|H.P. Corliss cylinder bore||1 l/8in.|
|L.P. Corliss & slide valve cylinder bores||1 5/8in.|
|Flywheel||l0in. dia. x 2 1/4 in. wide (as cast).|
All of them can be supplied with or without a condenser/air pump, however in full size practice an air pump, as it was always called, was fitted for economy, and really the model would look wrong without one. Add 7 inches to the length if an air pump is fitted. No.4 the Twin Tandem engine should have 2 air pumps, one for each side.
Before ordering any castings we advise customers to have the drawings first and sort out which engine they would like to build.
Although there are other combinations of engines shown on the drawings, at the moment we are only supplying castings for the above layouts.