VIEW OF SIMPLE CYLINDER.
(J. I. Case Threshing Machine Co.)
The steam engine was invented by James Watt, in England, between 1765 and 1790, and he understood all the essential parts of the engine as now built. It was improved, however, by Seguin, Ericsson, Stephenson, Fulton, and many others.
Let us first consider:
THE STEAM CYLINDER, ITS PARTS AND CONNECTIONS.
The cylinder proper is constructed of a single piece of cast iron bored out smooth.
The cylinder heads are the flat discs or caps bolted to the ends of the cylinder itself. Sometimes one cylinder head is cast in the same piece with the engine frame.
The piston is a circular disc working back and forth in the cylinder. It is usually a hollow casting, and to make it fit the cylinder steam tight, it is supplied on its circumference with piston rings. These are made of slightly larger diameter than the piston, and serve as springs against the sides of the cylinder. The follower plate and bolts cover the piston rings on the piston head and hold them in place.
