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).
Oil pressure figures for Phantom relief valves.
| Identifier | ExFiles\Box 66a\4\ scan0017 | |
| Date | 29th June 1926 | |
| To B.Y. from E.{Mr Elliott - Chief Engineer} for Mr. Shelton. c. to H.S. X 8205 E1/M29.6.26. PHANTOM RELIEF VALVES. X.8205 X.7205 In response to the query you raise concerning the Phantom oil pressure, Mr. Jenner has given me the following figures, which I have arranged in the form of a table :- | Chamber. | Min. pressures assuming all valves just opening. | Max. pressure assuming all valves just fully lifted. | Average pressures. | |----------------------|---------------------------------------------------------------------------------|------------------------------------------------------------------------------------|---------------------------| | Low pressure. | 1.75 lbs. O per sq. in. | 8.3 lbs. 6.6 per. sq. in. | 3.3 lbs. 5.025 lbs/ sq. in. | | Intermediate pressure. | 3 1/2 lbs. O per sq. in. (1.75 lbs/sq.in. spring pressure + 1.75 lbs.sq.in. back pressure.) | 16.6 lbs/ 13.2 sq.in. (8.3 spring pressure + 8.3 lbs. back pressure.) | 6.6 lbs. 10 lbs/ per sq.in. | | High pressure. | 28 1/2 lbs. 18.5 per sq.in. (25 lbs. spring pressure + 3 1/2 lbs. back pressure) | 55.6 lbs. 45.2 per sq.in. (39 lbs. spring pressure + 16.6 lbs. back pressure.) | 31.85 lbs. 42 lbs. per sq. in. | Our average figures as you will notice are above the standard, but of course the pressure will be dependent on the quantity of overflow oil which is passed in a Phantom, and which will vary according to the age of the engine. If this overflow oil is very large our spring pressure must be reduced. The figures underlined shew reduced pressures which might be adopted. Though we should like a lower rating spring worked out for the high pressure valve since this can be done with the use of a lower spring pressure. Another factor which enters into this question is the gauge of the steel used for the bow springs. We should like to make this gauge as light as possible consistent with the practical requirements of the valve. E.{Mr Elliott - Chief Engineer} | ||