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 testing of a special, enlarged Autovac float designed to prevent failures caused by high temperatures.
| Identifier | WestWitteringFiles\U\May1930-July1930\ Scan118 | |
| Date | 4th July 1930 | |
| ORIGINAL To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/AJL. c. Sg.{Arthur F. Sidgreaves - MD} c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} Ey. Mx.{John H Maddocks - Chief Proving Officer} _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Hs{Lord Ernest Hives - Chair}/AJL1/AD4.7.30. x3579 x7510 x5510 AUTOVAC PETROL FEED. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Self Draining Float. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ As the result of our pointing out to the Autovac manufacturers that the self draining float can be made to fail (and does fail in service) due to temperature effects, we have received from them a special Autovac float in which the self draining tube has been enlarged to 7/32" internal diameter; in addition the vent holes in this tube have been opened out proportionately. This is approximately five times larger than the present model. We have tested this under the same conditions where the present type fails viz. the Autovac, fitted with a float having a slight leak at the bottom, is allowed to function normally but the petrol is heated up artificially to 90°C; when this temperature is reached the suction to the Autovac is cut off immediately after the float chamber has been filled. The Autovac is then allowed to cool down, during this process the petrol vapour inside the self draining float condenses and the partial vacuum thus developed is replaced by petrol from the float chamber | ||