| GB Patent: GB-178,401,432 
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| Improvements on Steam or Fire Engines-Three Bar Motion and Steam Carriage | 
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| Patentee: |  |
 | James Watt (exact or similar names) - Birmingham, West Midlands County,  England |  
 
 
 
 
| Manufacturer: |  | Boulton & Watt - Birmingham, West Midlands County,  England |  
 
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| Patent Dates: |  
| Granted: | Apr. 28, 1784 |  Espacenet patent
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                        Joel Havens
 Wikipedia biography of James Watt
 Patent Specification
 "Vintage Machinery" entry for Boulton & Watt
 
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| Description: |  | Note: Early English patents were not originally numbered but they were later assigned consecutive numbers that run from #1 of 1617 to #14359 of September 1852. From Oct 1852 until 1916, patents were numbered by the year and started at patent #1 at the start of each year in January. The patent number used in DATAMP represents the year of issue and the patent number. This patent is #933 issued in the year 1769 
This patent covers aspects of Watt's double-acting engine, where steam pressure was alternately applied to either side of the piston. This was also an "expansive" engine, meaning that it used steam under greater-than-atmospheric pressure. The patent specification also described the concept of the steam hammer, which is believed to be the first time that this idea was ever written down. |  |