![](https://coimages.sciencemuseumgroup.org.uk/54/597/large_thumbnail_1945_0138.jpg)
Kenyon's pistonless steam engine indicator, 1878
- Made:
- 1878-1890
![Kenyon's pistonless steam engine indicator, 1878](https://coimages.sciencemuseumgroup.org.uk/441/199/small_thumbnail_smg00021632.jpg)
![Kenyon's pistonless steam engine indicator, 1878](https://coimages.sciencemuseumgroup.org.uk/302/765/small_thumbnail_smg00021632.jpg)
Kenyon's pistonless steam engine indicator, 1878
In this steam engine indicator, patented in 1878 by Mr. J. W. Kenyon, a Bourdon tube takes the place of piston and spring. The motion, under varying pressure, of the free end of the tube is multiplied by a lever in the ratio of about 5: 1, and the pencil is constrained to move in a straight line by Watt's parallel motion applied as in Richards indicator. The connection between the tube and the parallel motion is by a rod with ball joints which enables the pencil to be drawn back from the paper on the drum when required. The drum is fitted with a stop motion, consisting of a small lever by which it can be raised sufficiently to disengage a short driving peg attached to the cord pulley.