general layout of the valve gear
This type of winding engine was patented early in 1800. The most striking feature (for the time) is the absence of a beam and Watt parallel motion. The winder drum was placed high up over the cylinder and a Z-type arrangement of levers guided the piston rod. Built like this, the typical lever-engine was very high, and with the heavy rope-drum on top, it needed a house of massive construction. Winding drums of up to 20 feet diameter were no exception. With such a winder, at a typical coal pit of the area, only about 10 to 30 revolutions were required to complete a haul. Therefore, although the cylinder had plug-rod operated valves, it was usually run manually.
The present book gives design details of the most important engine parts, analysing notable lever-engines at Harton, Wearmouth, Murton, Seaham, Seaton and Ryhope collieries. This section is well illustrated with contemporary engravings, reproduced large-scale. Furthermore, a fully illustrated step-by-step description of the typical valve-gear and its operation is given. The Z-levers, by the way, could be particularly useful during shaft sinking. By extending one of the levers to protrude over the shaft, it could operate a pump rod.
The second part of the book looks at shaft and engine layout and (static) load counterbalancing. In the early days, single, partitioned, shafts of only 10' diameter were common. Rigid wood guides, usually two, served to prevent damage to the bratticing. Later, of course, shafts were made wider and iron conductors were applied.
The largest part of this book is devoted to short descriptions of all single-cylinder vertical lever-type winding engines the author has been able to trace in the North East. A chronology of all engines discussed; a survey of all sources used; and an index to the collieries where these engines operated, round off this fascinating book.
omvang - vi+100 pp - 20 illus
afmetingen - A4
uitvoering - paperback en hardcover