From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Analysis of pump issues, focusing on spring stress, location, and clearance calculations.
| Identifier | ExFiles\Box 27\1\ Scan251 | |
| Date | 6th July 1929 guessed | |
| -2- Some particles of grit would be sure to get under the valve in the piston head, which immediately would derange the pump. The spring could not possibly be less in diameter as it is already stressed on maximum load to 84,000 lbs.per sq.in. i.e. the safe stress. We might experiment with one of special section in order to give a mean load of 148 lbs. as friction accounts for the loss of about 10 lb./ sq.in. pressure - i.e. the average of six pumps in the test dept. came to a mean pressure of 78 lb/sq.in. instead of 88 lb/sq.in. With regard to the question of spring location the following are particulars. Inside location. Internal dia. of spring= .975 External dia. of piston = .920 Total clearance = .055 Maximum amount of dislocation = .055 / 2 = .0275. Outside location. Effective Internal Dia. of filter = 1.378 Outside diameter of spring = 1.325 Total clearance = .053 Maximum amount of dislocation = .053 / 2 = .0265. For a working job these figures speak for themselves. | ||