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Diagram of cylinder and piston valve. The valve is next opened by moving it to the right, allowing the clear space in the middle of the valve to align with the channel in the cylinder above it. Piston valves are one form of valve used to control the flow of steam within a steam engine or locomotive.
Collects steam at the top of the boiler (well above the water level) so that it can be fed to the engine via the main steam pipe, or dry pipe, and the regulator/throttle valve. [2] [5] [6]: 211–212 [3]: 26 Air pump / Air compressor Westinghouse pump (US+) Powered by steam, it compresses air for operating the train air brake system.
In the simple case, this can be a relatively simple task as in the internal combustion engine in which the valves always open and close at the same points. This is not the ideal arrangement for a steam engine, though, because greatest power is achieved by keeping the inlet valve open throughout the power stroke (thus having full boiler pressure, minus transmission losses, against the piston ...
Double-beat poppet valves became widely used during the nineteenth century. Francis Stevens invented the Stevens valve gear, a double beat poppet valve, in 1839. It was used throughout the nineteenth century and in the early years of the 20th, on side-wheel paddle steamer engines, including the grasshopper engine, in the United States. [4]
Galloway uniflow steam engine, now in Thinktank, Birmingham Science Museum. Steam entry is usually controlled by poppet valves (which act similarly to those used in internal combustion engines) that are operated by a camshaft. The inlet valves open to admit steam when minimum expansion volume has been reached at the start of the stroke.
A Corliss steam engine (or Corliss engine) is a steam engine, fitted with rotary valves and with variable valve timing patented in 1849, invented by and named after the US engineer George Henry Corliss of Providence, Rhode Island. Corliss assumed the original invention from Frederick Ellsworth Sickels (1819- 1895), who held the patent (1829) in ...
In the 19th century, most steam locomotives used slide valves to control the flow of steam into and out of the cylinders. In the 20th century, slide valves were gradually superseded by piston valves, particularly in engines using superheated steam. There were two reasons for this: With piston valves, the steam passages can be made shorter.
The valve opens to admit steam to the cylinder just before the start of a piston stroke. The pressure of this steam provides the driving force. Soon before the space on one side of the piston starts to contract, the valve starts to release steam from that space to the atmosphere, so as not to impede the movement of the piston.