Steam Distribution

the automatic control process by which live steam is admitted to the cylinder of a steam engine and exhaust steam is discharged. The steam is admitted and discharged by steam-distributing devices (slide valves, valves, and cocks) that shut off and open the admission and exhaust ports of the cylinder according to the position of the piston. This is done by the piston itself in uniflow (reciprocating) engines. The most common type of steam distribution is slide-valve steam distribution. Steam-distribution units can also provide for reversal when necessary, for example, on steamships and steam locomotives.