Thomas Newcomen was born in Dartmouth, Devon in 1663 and established himself as an ironmonger in his home town. Some of his biggest customers were Cornish tin mine owners, who faced considerable difficulties with flooding as mines became progressively deeper. The standard methods to remove the water – manual pumping or teams of horses hauling buckets on a rope – were slow and expensive, and they sought an alternative.
Contemporary engines worked by using condensed steam to make a vacuum, but whereas Thomas Savery’s pump of 1698 had just used the vacuum to pull the water up, Newcomen created his vacuum inside a cylinder and used it to pull down a piston. He then used a lever to transfer the force to the pump shaft that went down the mine. It was the first practical engine to use a piston in a cylinder. Casting the cylinders and getting the pistons to fit was pushing the limit of existing technology, so Newcomen deliberately made the piston marginally smaller than the cylinder and sealed the gap with a ring of wet leather or rope. To avoid infringing Savery’s patent Newcomen was forced to go into partnership with him.
His first working engine was installed at a coalmine at Dudley Castle in Staffordshire in 1712. It had a cylinder 21 inches in diameter and nearly eight feet long, and it worked at twelve strokes a minute, raising ten gallons of water from a depth of 156 feet – approximately 5.5 horse power. The engines were rugged and reliable and worked day and night, but were extremely inefficient.
Newcomen engines were very expensive but were nevertheless very successful. By the time Newcomen died on 5 August 1729 there were at least one hundred of his engines in Britain and across Europe. Edited from Thomas Newcomen (1663 – 1729).