Thomas Newcomen - Developing The Steam Engine

Developing The Steam Engine

Newcomen's great achievement was his steam engine, developed around 1712, combining the ideas of Thomas Savery and Denis Papin. It is likely that Newcomen was already acquainted with Savery, whose forebears were merchants in south Devon. Savery also had a post with the Commissioners for Sick and Hurt Seamen, which took him to Dartmouth. Savery had devised a 'fire engine', a kind of thermic syphon, in which steam was admitted to an empty container and then condensed. The vacuum thus created was used to suck water from the sump at the bottom of the mine. The 'fire engine' was not very effective and could not work beyond a limited depth of around thirty feet.

Newcomen replaced the receiving vessel (where the steam was condensed) with a cylinder containing a piston. Instead of the vacuum drawing in water, it drew down the piston. This was used to work a beam engine, in which a large wooden beam rocked upon a central fulcrum. On the other side of the beam was a chain attached to a pump at the base of the mine. As the steam cylinder was refilled with steam, readying it for the next power stroke, water was drawn into the pump cylinder and expelled into a pipe to the surface by the weight of the machinery. Newcomen and his partner John Calley built one of the first engines at the Conygree Coalworks near Dudley in the West Midlands. A working replica of this engine can be seen at the Black Country Living Museum nearby.