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).
Explaining the suction difference in the Autovac system due to a non-return valve.
| Identifier | ExFiles\Box 68\2\ scan0060 | |
| Date | 13th November 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. Expl. No. +8510 REF: Hs{Lord Ernest Hives - Chair}4/LG13.11.25. To CWB. from Hs.{Lord Ernest Hives - Chair} "AUTOVAC". x8510 x8579 Some considerable time ago you raised the point in connection with one of our reports on the Autovac - Hs{Lord Ernest Hives - Chair}/AJL/LG14.8.25. that the curves showed the suction in the autovac to be higher than the suction in the induction pipe. At the time I could not explain the reason for this. We have however been going over the matter again and we find that this is quite in order and is due to the fact that on the pipe between the induction pipe and the autovac there is a non-return valve so that it is the peak of the suction which is registered in the autovac, whereas the suction measured in the induction is the mean. One can understand that the non-return valve mentioned is not essential on a 6-cyl. engine but would be very necessary when one came to one or two-cyl. engines. Hs.{Lord Ernest Hives - Chair} | ||