Uniflow Steam Engine

A uniflow steam engine is a reciprocating steam engine in which steam moves in only one direction through each half of the cylinder, always entering at the hot ends and exhausting through ports at the cooler middle, rather than reversing direction the way conventional counterflow engines do. This one direction flow keeps the cylinder walls from repeatedly heating and cooling, reducing thermal losses and allowing greater expansion within a single cylinder. Jacob Perkins first used the principle in Britain in 1827, Leonard Jennett Todd patented it in 1885, and the German engineer Johann Stumpf built the first commercial stationary uniflow engine in 1908 and 1909, with the design later finding its widest use in marine engines such as the Skinner Unaflow engines of the late 1930s and 1940s. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/