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).
The failure of the 'B' Side of a 2-B-50 petrol pump.
| Identifier | ExFiles\Box 149\3\ scan0162 | |
| Date | 13th December 1940 | |
| 1268 To Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby} Copy to Rm{William Robotham - Chief Engineer}/Hym. Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby}7/ET.13.12.40. 2-B-50 PETROL PUMP Failure of "B" Side. --------------- This pump is marked 28-G-VI and appears to have been on 2-B-50 for the full 15.656 miles apart from some short tests with A.C. mechanical pumps in June 1939. The pump has diaphragms consisting of two layers of neoprene, with no provision for the swelling of the neoprene. There were no rubber water corners fitted and the drain holes in the cast iron pots were not at the bottom, but between two of the fixing screw holes, one of which was at the bottom. The drain hole is therefore 30° round and there is an arc of 60° at the bottom of the roller chamber with no means of drainage. The car was used for fairly extensive servo tests through splashes and so it was to be expected that there would be some rust. On dismantling, large quantities of rust were found on both sides, but the working parts were not affected. There was some "fluff" on "B" side filter, but the valve seatings were fair. The rollers appeared to have been packed with grease which had become thickened by a black dust presumably from the diaphragms. There was also some rust present, the result being that the rollers stuck and embedded themselves in the diaphragm, which had probably already swelled. It may be that the rollers seized first due to this swelling, and that the black dust only formed from the rollers afterwards, cutting into the diaphragms. On both sides there were very appreciable quantities of sediment at the bottoms of the diaphragm chambers, thus encouraging the sticking of the bottom rollers on the other side of the diaphragms. On both units there was pitting of the contact points, but it was worst on "B" side and was, in this case, accompanied by a large quantity of carbon, the latter being the only important difference between the condition of the two sides. The pump has probably done a good mileage, which fact is enough to excuse the pitting and sooting of the contacts. The rollers are no longer packed in grease and there is no provision for the swelling of the neoprene. The drain holes in the cast iron pots are now located exactly at the bottom and are covered by the new rubber water excluders. Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby} | ||