Watt's steam engine indicator

maker:
James Watt
Watt's steam engine indicator, with line diagram Watt's steam engine indicator, with line diagram Watt's steam engine indicator, with line diagram Watt's steam engine indicator, with line diagram Watt's steam engine indicator, with line diagram Watt's steam engine indicator, with  line diagram

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Creative Commons LicenseThis image is released under a CC BY-NC-SA 4.0 Licence

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License this image for commercial use at Science and Society Picture Library

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Creative Commons LicenseThis image is released under a CC BY-NC-SA 4.0 Licence

Buy this image as a print 

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License this image for commercial use at Science and Society Picture Library

License

Creative Commons LicenseThis image is released under a CC BY-NC-SA 4.0 Licence

Buy this image as a print 

Buy

License this image for commercial use at Science and Society Picture Library

License

Creative Commons LicenseThis image is released under a CC BY-NC-SA 4.0 Licence

Buy this image as a print 

Buy

License this image for commercial use at Science and Society Picture Library

License

Creative Commons LicenseThis image is released under a CC BY-NC-SA 4.0 Licence

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License this image for commercial use at Science and Society Picture Library

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Watt's steam engine indicator, with line diagram
Science Museum Group
© The Board of Trustees of the Science Museum

Watt's steam engine indicator, with line diagram
Science Museum Group
© The Board of Trustees of the Science Museum

Watt's steam engine indicator, with line diagram
Science Museum Group
© The Board of Trustees of the Science Museum

Watt's steam engine indicator, with line diagram
Science Museum Group
© The Board of Trustees of the Science Museum

Watt's steam engine indicator, with line diagram
Science Museum Group
© The Board of Trustees of the Science Museum

Watt's steam engine indicator, with line diagram
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Watt's steam engine indicator, with box and 2 line diagrams

This instrument was introduced by engineers Boulton & Watt in 1796 for the purpose of assisting them in adjusting the valves of a steam engine. In Watt's patent of 1782 there is a diagram of the pressures throughout the stroke of an engine working expansively, but this is clearly the result of calculation. The instrument may have been developed from the vacuum gauge (see inv. 1876-1260). By the addition to such an apparatus of a pencil to the piston rod and a sheet of paper moved transversely to it -features attributed to John Southern, one of Watt's staff-the instrument became a recorder of the pressure existing in the cylinder at every point of the stroke, and gave a diagram from which the work done during the stroke was easily determined. The instrument was kept secret, and was entrusted only to the staff of the firm; that exhibited belonged to the agent in Manchester, while the diagram was taken in 1840 by Prof. E. Cowper.

Details

Category:
Motive Power
Object Number:
1890-83
Materials:
brass (copper, zinc alloy) and mahogany (wood)
type:
indicator
credit:
Mr. E.A. Cowper.