This section is from the book "The English And American Mechanic", by B. Frank Van Cleve. Also available from Amazon: The English And American Mechanic.
Point of Cutting off: | Gain in Fuel. | Initial Pressure Required. | |
Cutting Off; | Full Stroke. | ||
Stroke. | PerCent. | Lbs. | Lbs. |
⅞ | 11.7 | 101 | 1. |
¾ | 22.4 | 103 | 1. |
⅝ | 32. | 109 | 1. |
½ | 41. | 1.18 | 1. |
Point of Cutting Off. | Gain in Fuel. | Initial Pressure Required. | |
Cutting Off. | Full Stroke. | ||
Stroke. | Per Cent. | Lbs. | Lbs. |
3/8 | 49.6 | 1.32 | 1. |
¼ | 68.2 | 1.67 | 1. |
1/8 | 67.6 | 2.6 | 1. |
The* Relative Effect of Steam during Expansion is obtained from the preceding rule.
The Mechanical Effect of Steam in a cylinder is the product of the mean pressure in lbs., and the distance through which it has passed in feet.
The Pressure at the End of a Stroke, or at any Given Point of the Stroke, is obtained by dividing the initial pressure by the portion of the stroke performed when the steam is cut off.
 
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