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).
Comparison of the performance and limitations of various oil purification units under test.
| Identifier | ExFiles\Box 135\3\ scan0254 | |
| Date | 11th March 1938 guessed | |
| -2- GENERAL During the first 15 hours this unit was under test, the limit of purification was reached more slowly than with either the Smith or the Luber-Finer. Also there was a far greater rate of leakage across the unit, due presumably to the filter element being raised off the joint face by the pressure when the purification limit was reached. The same unit when re-tested using dirtier oil, gave a slightly higher percentage purification increase, whilst the leakage across the unit remained practically constant throughout. A.C. This unit behaved similarly to the General during the first test, but during a retest the percentage purification increase was less than on the first occasion, and the leakage across the unit decreased. ----------------- Considering the functioning of these units under engine conditions when commencing with new oil, the Smith should prove generally the most satisfactory since it combines average percentage purification increase with reasonable capacity, and its limitation of purification is defined by the cessation of flow. It will possibly require slightly earlier renewal than either the General or A.C. types. A false impression is created by the two latter types in that no indication is given as to when the purification limit is reached, consequently the units may appear to be still functioning (on disconnecting the outlet pipe) whereas in fact no useful work is being accomplished. The Luber-Finer appears to lack absorptional capacity. Rm{William Robotham - Chief Engineer}/W.Bell. | ||