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James Watt's Patent for the Separate Condenser

When
1765–1769
Where
Watt's workplace context at the University of Glasgow (1763); conception site unspecified; British patent process
Episodes
3

In 1769 James Watt secured British Patent No. 913 for his separate condenser, an improvement to the Newcomen steam engine he had conceived in 1765 while an instrument maker at the University of Glasgow. The specification was accepted on 5 January 1769 and enrolled on 29 April 1769, reconciling both dates.

Episodes

  1. 1765 · Watt's workplace context at the University of Glasgow (1763); conception site unspecifiedConception of the Separate Condenser

    Watt conceived the separate condenser in 1765 after repairing a model Newcomen engine at Glasgow, addressing its heat waste.

  2. 5 January 1769 · British patent processPatent Specification Accepted

    The specification of Patent No. 913 for the separate condenser was accepted on 5 January 1769.

  3. 29 April 1769 · British patent processPatent Enrolled

    The patent specification was enrolled on 29 April 1769, completing the patenting of the separate condenser.

Background and detail

Background. James Watt worked as an instrument maker at the University of Glasgow, where he became interested in steam engine technology. In 1763 he was assigned the repair of a model Newcomen engine and noted its inefficiency, observing the significant heat required to warm the cylinder before steam could enter without immediately condensing.

The Separate Condenser. In 1765 Watt conceived the idea of a separate condensation chamber, which he called a "condenser". Because the condenser and working cylinder were separate, condensation occurred without significant loss of heat from the cylinder, eliminating the waste that occurred in Newcomen engines and radically improving power, efficiency, and cost-effectiveness.

Patent No. 913. Watt's patent, No. 913, was titled "A method of lessening the consumption of steam in steam engines" – the separate condenser. The specification was accepted on 5 January 1769 and enrolled on 29 April 1769. Matthew Boulton helped Watt obtain the patent, having cleared his debts and funded a prototype engine at Kinneil House.

People involved

  • James Watt · Scottish inventor who devised the separate condenser and obtained the patent
  • Matthew Boulton · Backer who cleared Watt's debts, funded a prototype, and helped secure the 1769 patent

Sources

  1. James Watt Wikipedia, revision of 2026-08-22
  2. Watt steam engine Wikipedia, revision of 2026-09-20

Machine-drafted from the cited Wikipedia passages and checked by a reviewing model, not by a human editor. Every passage cites the revision it was written from; dates and places follow those passages.