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 a 20HP water pump failure, identifying three possible causes for end pressure on the rotor spindle.
| Identifier | ExFiles\Box 77\4\ scan0116 | |
| Date | 18th February 1924 | |
| EP.{G. Eric Platford - Chief Quality Engineer} c. SFI. c. Hs.{Lord Ernest Hives - Chair} c. Hm.{Capt. W. Hallam - Head Repairs} +4231 BY6-F19.S.24. 20HP. WATER PUMP. CHASSIS 52.S.3. +4231 EP{G. Eric Platford - Chief Quality Engineer}3/H18.2.24. The failure on the above part is clearly due to end pressure being brought on the rotor spindle from some cause or another. The possible causes as I see them are three:- (1) The suction of the pump would result in the rotor itself tending to move out towards the cover, due to atmospheric pressure on the opposite end of the spindle. (2) The fit of the keys in the boss on the flexible coupling and those on the shaft was probably too tight, with the result that when fitted into position the fabric coupling was pushed out of line because it could not exert force to compel the boss it carries to move to its correct position on the spindle. This again would result on a steady elastic pressure being caused by the fabric coupling in such a direction as to push the rotor on to its lignum vitae thrust piece. (3) The drive and the pump might possibly have been short on the centres, so that the keyed boss carried by the fabric would, under such conditions, reach the end of the keyways on the shaft before it got into correct alignment. It would be of distinct interest if EP{G. Eric Platford - Chief Quality Engineer}, could get possession of the drive to see whether the fit of the keys on the spindle is too tight. Hm{Capt. W. Hallam - Head Repairs}, should be able to by watching the wear of the thrust piece to tell us whether there is a general tendency to wear the block, if so, it is undoubtedly due to the suction effects and modifications will have to be made. So far, our experience does not point this way. I suggest the Works Policy is the best item to charge to. BY.{R.W. Bailey - Chief Engineer} [Signature] | ||