Thomas Savery

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Thomas Savery
Personal information
Name Thomas Savery
Nationality English
Birth date c. 1650
Birth place Modbury, Devon, England
Date of death 1715
Work

Thomas Savery (c. 1650 - 1715) was an English inventor, born at Shilstone, a manor house near Modbury, Devon, England.

Savery became a military engineer, rising to the rank of Captain by 1702, and spent his free time performing experiments in mechanics. In 1696 he took out a patent for a machine for polishing glass or marble and another for "rowing of ships with greater ease and expedicion than hitherto beene done by any other" which involved paddle-wheels driven by a capstan and which was dismissed by the Admiralty.

On July 2, 1698 Savery patented an early steam engine, which he demonstrated to the Royal Society on June 14, 1699. The patent has no illustrations or even description, but in 1702 Savery described the machine in his book The Miner's Friend; or, An Engine to Raise Water by Fire[1], in which he claimed that it could pump water out of mines.

Savery's engine had no piston, and no moving parts except from the taps. It was operated by first raising steam in the boiler; the steam was then admitted to the working vessel, allowing it to blow out through a downpipe into the water that was to be raised. When the system was hot and therefore full of steam the tap between the boiler and the working vessel was shut, and if necessary the outside of the vessel was cooled. This made the steam inside it condense, creating a partial vacuum, and atmospheric pressure pushed water up the downpipe until the vessel was full. At this point the tap below the vessel was closed, and the tap between it and the up-pipe opened, and more steam was admitted from the boiler. As the steam pressure built up, it forced the water from the vessel up the up-pipe to the top of the mine.

Savery took great care to stress how powerful his engine was, and was the first to use the term "horsepower". However, his engine had three serious problems. First, every time water was admitted to the working vessel much of the heat was wasted in warming up the water that was being pumped. Secondly, the second stage of the process required high-pressure steam to force the water up, and the engine's soldered joints were barely capable of withstanding high pressure steam and needed frequent repair. Thirdly, the engine could only raise water about {convert|40|ft|m} and as a result had to be installed far down in a mine, and a deep mine would need a series of engines to raise water all the way to the top.

A few Savery engines were tried in mines, an unsuccessful attempt being made to use one to clear water from a mine at Broadwaters in Wednesbury, then in Staffordshire.[2], and one was built to control the water supply at Hampton Court, while another at Campden House in Kensington operated for 18 years. [3].

Savery worked for the Sick and Hurt Commissioners, contracted the supply of medicines to the Navy Stock Company, which was connected with the Society of Apothecaries. His duties on their behalf took him to Dartmouth, which is probably how he came into contact with Thomas Newcomen.

The Fire Engine Act of 1698 had extended Savery's patent to 1733; his patent covered all engines that raised water by fire and Newcomen was forced to go into partnership with Savery. By 1712, arrangements had been made with Newcomen to develop Newcomen's more advanced design of steam engine, which was marketed under Savery's patent. Newcomen's engine worked purely by atmospheric pressure, thereby avoiding the dangers of high-pressure steam, and used the piston concept invented in 1690 by the Frenchman Denis Papin to produce the first steam engine capable of raising water from deep mines.[4]

When Savery died in 1715 a Joint Stock Company was set up, known as 'Proprietors of the invention for raising water by fire' and this issued licences to others for the building and operation of Newcomen engines.

Several later pumping systems may be based on Savery's pump. For example, the twin-chamber pulsometer steam pump was a successful development of it[5]

[edit] External links

[edit] Notes

  1. ^ Savery, Thomas (1702). The Miner's Friend; or, An Engine to Raise Water by Fire. London: S. Crouch. ISBN http://books.google.co.uk/books?id=v_-yJ5c5a98C. 
  2. ^ S. Shaw, History and Antiquities of Staffordshire (1798-1801) II(1), 120
  3. ^ E. I. Carlyle, 'Savery , Thomas (1650?–1715)', rev. Christopher F. Lindsey, Oxford Dictionary of National Biography, Oxford University Press, 2004, accessed 29 April 2006 URL
  4. ^ L. T. C. Rolt and J. S. Allen, The Steam Engine of Thomas Newcomen (Landmark Publishing, Ashbourne 1997).
  5. ^ SPP Pumps