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Piston valve (steam engine)
Form of valve within a steam engine or locomotive / From Wikipedia, the free encyclopedia
For other applications of piston valves, see Piston valve.
Piston valves are one form of valve used to control the flow of steam within a steam engine or locomotive. They control the admission of steam into the cylinders and its subsequent exhausting, enabling a locomotive to move under its own power. The valve consists of two piston heads on a common spindle moving inside a steam chest, which is essentially a mini-cylinder located either above or below the main cylinders of the locomotive.
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