Newcomen steam engine

Before the Newcomen steam engine steam had been used only in various devices, called steam fountains, for raising water. In 1706 the first successful attempt to combine the ideas of these devices into an economical and convenient machine was made by Thomas Newcomen This machine was called an atmospheric steam engine. It consisted of a boiler A, in which the steam was generated, and a cylinder B, in which a piston moved. When the valve V was opened, the steam pushed up the piston P. At the top of the stroke, the valve V was closed, the valve V' was opened, and a jet of cold water from the tank C was injected into the cylinder, thus condensing the steam and reducing the pressure under the piston. The atmospheric pressure above then pushed the piston down again.

This machine was used to pump water from mines. It consumed a great deal of fuel, because the cold water cooled the cylinder walls so much that when the steam was turned in, much steam condensed before the piston was raised.

See also: Steam engine, Watt steam engine