John Smeaton
continued
Steam engines
Smeaton's interests were certainly wide-ranging and he was always aware of what his contemporaries were doing. So, he followed with interest the technical developments in steam engine design — steam engines were the power sources of the age.
Before the Industrial Revolution, keeping mines free of water was a constant problem. In 1698, Captain Thomas Savery (c1650-1715) patented an atmospheric steam engine, which it was hoped could be used for pumping and lifting. A vacuum was created below its piston so the piston moved downwards under the pressure of the atmosphere above. The vacuum was created by condensing low-pressure steam by applying water to the outside of a coal-fired boiler. However, the engine turned out to be ineffective at raising water either from a great depth or in quantity.
In 1712, Thomas Newcomen (1664-1729) made his first successful engine, which prompted condensation by injecting water directly into the cylinder. The moving piston was connected to a beam that rocked up and down, making it excellent for pumping. The engine was easy to construct and power could be increased by using larger cylinders and boilers. Within 20 years there were more than 100 'Newcomen engines' in Britain and Europe, and it is claimed that more than 2,000 existed by 1800.
Smeaton took the Newcomen design and improved it. His first pumping engine was for the New River Company in Islington, London, where Robert Mylne was engineer. Smeaton designed a beam engine that replaced their horse-driven pumps in 1769. However, the results were disappointingly inefficient and he was determined to do better. He amassed data from 15 working engines in the Newcastle area and 12 in Cornwall, expressing the results in terms of their power and efficiency.
He built an experimental engine at Austhorpe in 1770 and began rigorous testing. It had a 250mm (10in) diameter cylinder and developed a little over 0.75kW (1hp). Over the course of some 130 tests, Smeaton altered factors and observed differences, gradually improving performance. After two years' work he drew up a comprehensive table of properties for engines with cylinders of 0.25-1.83m (10-72in) diameters. He designed 13 engines altogether, four of them returning engines with waterwheels.
Then in 1772, Smeaton received a request to design a pumping engine for Long Benton colliery in Northumberland. He suggested one with a 1.32m (52in) diameter cylinder. It began operating in February 1774, and tests in May showed that it developed about 30kW (40hp) — a 25 percent increase on the most efficient steam engine in the country to date.
Smeaton's only overseas commission for a pumping engine was from the Russian naval dockyard at Kronstadt on the River Neva near St Petersburg, where two windmill pumps were used to empty a dry dock. In 1773, he recommended an engine developing 45kW (60hp). However this would be expensive to run and he advised keeping the better of the windmills as backup. The engine became operational in 1777. In 1819, engineer John Farey observed first hand that the engine was still working well.
Another improvement in efficiency was achieved with Smeaton's 1775 steam engine at Chacewater mine in Cornwall, which he designed to develop 54kW (72hp) to replace a pair of engines that together managed only 45kW (60hp).
At Prosperous Pit near Newcastle, Smeaton's arrangement of returning engine, with waterwheel and winding machinery, replaced a horse gin in 1777. The engine had a 660mm (26in) diameter cylinder and lifted 318kg of coal every two minutes from a depth of almost 152m. The 3.05m diameter boiler was fuelled with waste coal from the mine. This worked so well that an identical engine was constructed in 1778, and a larger one in 1785.
The success of these winding engines led Smeaton to design one for the Walker colliery in 1783, this time raising 13.3 tonnes of coal per hour from a depth of 174m. It was to be his last steam engine.
Meanwhile in 1765, James Watt (1736-1819) made a breakthrough that was to change the way steam engines were built. He condensed in a separate vessel instead of inside the piston cylinder. So the cylinder did not need to be heated and cooled, which was safer, and the engine worked faster and more efficiently. Watt joined forces with Birmingham engineer Matthew Boulton (1728-1809) in 1774, and they produced the new engines in Soho in Birmingham from 1776.
Smeaton was aware of this and enjoyed a long series of correspondence with Boulton and Watt. He admired the advances they made, and even recommended their engines to some of his clients. When Watt was elected a Fellow of the Royal Society in 1785, Smeaton's name was first on the proposal form.
All items by John Smeaton  •  Everything built ... 1724 - 1792
main references  BDCE1, DNB, JS
painting of Smeaton  courtesy Institution of Civil Engineers
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John Smeaton
Elevation and plan of the engine for raising water for the coal gin at the Prosperous Pit near Newcastle. Smeaton's arrangement of returning engine, with waterwheel and winding machinery, replaced a horse gin in 1777.
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