This Corliss Steam Engine model was built from a casting kit produced by Coles Power Models, Inc. of Ventura, California. Coles Power Models has been producing this casting kit since the early 1940s. This model was built by Charles DeFord of Battle Creek, Michigan. The build date is unknown. It represents a Corliss engine from 1887.
Specifications
Base 22" x 14", Bore 1-1/4", Stroke 2-1/2", Flywheel 8" diameter and weight complete about 75 lbs.
Coles Power Models Catalog from 1960
The model shown in the Coles Power Models catalog was built by Mr. A.W. Ray of Akron, Ohio. This engine took first prize at the 1942 Philadelphia Model Show.
Notes on the Corliss Valve Gear Design
The Corliss valve gearpossesses the following important advantages: 1. Reduced clearance volume and clearance surface, owing to the shortness of the admission and exhaust passages obtained by placing the valves close to the ends of the cylinders. In such cylinders the clearance will vary from 3 to 5% of the piston displacement. 2.Separate valves are used for steam and exhaust, the steam valves being at the top corners of horizontal cylinders and the exhaust valves at the bottom corners, by which means, during the flow of the steam from the cylinder, the exhaust surfaces are swept clear of water and a natural system of drainage is thus provided. This advantage applies more especially to horizontal cylinders. 3. It maintains a wide opening during admission of steam with a sudden return of the valve at cut off, thus preventing wire drawing of the steam during admission. 4. It permits of independent adjustment of admission and cut off, release and compression. 5.It provides an easy and effective method of governing engines of large power, by regulation of the cut off, through the action of a governor on the comparatively light working parts of the valve disengaging gear. It is frequently claimed for the employment of separate steam and exhaust valves that condensation is reduced because the entering steam coming through a separate passage, and not through that through which the steam is exhausted, does not come into contact with surfaces which have just been cooled down by the comparatively cold exhaust steam, as is the case when the port is common to both admission and exhaust; but this claim is only valid if the area of clearance surface be reduced by the arrangement of separate valves, because in any case, all the surface up to the exhaust valve must be heated up each stroke whether the steam is admitted through the same of through a separate port. One important objectionto the Corliss valve gear is the limitation of the speed of rotation of engines fitted with it owing to its action being dependent upon the engagement and tripping of catches.
