THE GREENE GRIDIRON VALVE ENGINE

Greene gridiron valve engine

Courtesy of John P. Wilcox, 47 Deland Ave., Columbia, Ohio 43214. Frame of the Greene gridiron valve engine in storage awaiting restoration. Cylinder is !2 x 30 bore and stroke, flywheel (not shown) is 10 foot diameter by 17 face. Built by the Providence

John P. Wilcox

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47 Deland Ave. Columbus, Ohio 43214

Last summer we were so fortunate as to become the owner of the ancient Greene steam engine that powered the Cheraw Sash Door and Lumber Co. of Cheraw, South Carolina for many years. After two long truck trips over the mountains and some on-the-scene 'head scratching' over how to get the ten-foot flywheel up out of its pit, all her parts are now home, cleaned, and greased. The accompanying picture shows the frame in storage awaiting restoration at Trail Run Station, Monroe County, Ohio.

The Greene engine was patented in 1855 by Mr. Noble T. Greene, six years after George Corliss received his basic patents. Like the Corliss, it has a drop cut-off valve gear with dashpots, and the separate inlet and exhuast valves are located at the four corners of the cylinder. There the similarity ends, however, as the valves are of the flat 'gridiron' type and the arrangement of the mechanism that works them is entirely different. The inlet valves are tripped by a 'plug-tree' mechanism similar to that used on the early Newcomen and Cornish engines. An eccentric on the crankshaft works a slide on the side of the cylinder through the usual reciprocating rods. To open the valves, lugs projecting from the top of the slide engage fingers hanging from the ends of the two rock shafts running to the upper part of the cylinder. As the slide continues it motion, the ends of the fingers are swung up until they slip off the lugs, allowing the valves to snap shut. In the Greene, the governor varies the height of the lugs to control the point of cut-off. Unlike the single-eccentric Corliss engine, it can cut off at any point from the beginning of the stroke to nearly full stroke.

The exhaust valves slide crosswise under the cylinder and are driven by an oscillating side shaft from a second eccentric.

Mr. Corliss brought suit and managed to halt production of the Greene engine for a time, but its manufacture was resumed at the expiration of the Corliss patents and was continued for several years by the Providence, R.I. Another example is on display in the Ford Museum.

While in Cheraw we viewed an even larger steam engine in another factory there. It was a Murray Corliss, with twelve foot flywheel. A relatively plain engine and with quite a bit of rust damage, but it could be restored if anybody wants a big engine badly enough.