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).
Vibration and pressure tests conducted on 16 m.m. and 24 m.m. tubes.
| Identifier | ExFiles\Box 88\5\ scan0201 | |
| Date | 1st August 1929 guessed | |
| 2. E.2861 1. Vibration A sample of each size complete with ends was subjected to vibration in the apparatus shewn on Fig.1. Tube dimensions were not as shewn on this sketch which only shews the principle. The lengths of tube used were 10" and these were bent through 90°. The vibration was applied for a period of 232 hours and during this time the tubes were subjected to an internal pressure of 6 ft. of paraffin (about 2.2 lb.per sq.inch). The outside of the tubes was painted with a mixture of whiting and methylated spirits to show up very small leakages. At the conclusion of this period the pipes were subjected to an internal pressure of paraffin up to 300 lb.per sq.inch in order to cause bursting, serious leakage, or pulling out of the metal tubes from the glands. During this operation the fixed ends of the tubes were freed so that there was no external axial resistance to any tendency of the metal tubes to be forced out of the glands. After this test the 16 m.m. tube, which survived was subjected for a period of 3½ hours to an internal pressure of petrol (80% Aviation Spirit, 20% Benzol) of 50 lb.per sq.inch after which it was cut up for examination. No leakage of this kind was observed during the period of 232 hours (47 million reversals). After this period the pipes were subjected to the following pressures with the results below:- | Pressure | Remarks. 16 m.m. | Remarks 24 m.m. | | :--- | :--- | :--- | | Up to- 200 lb.per sq.in. | No leakage. Satisfactory | No leakage. Satisfactory. | | 210 ' ' | ditto. | Leaking between end adaptor and pipe slightly. | | 250 ' ' | ditto. | Same but worse. | | 300 ' ' | ditto. | Same but still worse. | The rubber packing glands satisfactorily gripped the metal tubes, the only leak being where the adaptor butts against the "Superflexit" and this only on the larger tube. During the petrol pressure test conducted on the 16 m.m. tube after the above treatment, no signs of leakage were visible although it had previously withstood 300 lb.per sq.inch paraffin pressure. When opened up it was noticed that the gland rubber was in excellent condition and the liquid had not penetrated completely through the "cellophane" lining. It / | ||