Search results
Results from the WOW.Com Content Network
The Stephenson valve gear or Stephenson link or shifting link [1] is a simple design of valve gear that was widely used throughout the world for various kinds of steam engines. It is named after Robert Stephenson [ 2 ] but was invented by his employees.
Stephenson valve gear - most common valve gear in the 19th century, normally inside the locomotive frame. William T. James valve gear 1832, used first by Baltimore and Ohio Railroad, United States. Allan valve gear, a straight-link valve gear. It is fitted to 0-4-0WT "Dolgoch", preserved on the Talyllyn Railway.
The valve gear, actuated by connection to the driving wheels, ensures that steam is delivered to the piston with precision. Types are slide valves, piston valves or poppet valves. [2] [3]: 62 Valve chest / Steam chest Valve chamber next to the cylinder (24) containing passageways to distribute steam to the cylinders. [6]: 41 [3]: 75 Firebox
Diagram of Stephenson valve gear controlled by a screw reverser The two pistons of the steam reverser can be seen at the extreme left on this Bulleid Merchant Navy class. In the screw reverser mechanism (sometimes called a bacon slicer in the UK), the reversing rod is controlled by a screw and nut, worked by a wheel in the cab.
The first of these were the link valve gears, particularly the Stephenson link valve gear. This uses a pair of eccentrics with a sliding link mechanism between them that acts as a mechanical adding device. Selecting intermediate positions provides a valve actuation with the effect of increasing cut-off.
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Donate
The usual locomotive valve gears such as Stephenson, Walschaerts, and Baker valve gear, can be used with either slide valves or piston valves. Where poppet valves are used, a different gear, such as Caprotti valve gear may be used, though standard gears as mentioned above were used as well, by Chapelon and others.
They were constructed as saturated steam engines, rebuilt with superheaters later as class B6s, and had Piston valves and Stephenson valve gear. A total of 79 were built by Baldwin and Lima, in addition to Altoona, between 1902 and 1913. [1] The next version built was the B6sa, 55 of which were built at Altoona during 1913–1914.