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).
Description and list of advantages for a double-acting autovac tank model originating from Germany.
| Identifier | ExFiles\Box 40\3\ Scan056 | |
| Date | 12th March 1926 | |
| X.3575 R.{Sir Henry Royce} from E.{Mr Elliott - Chief Engineer} c. to CJ. c. to DA.{Bernard Day - Chassis Design} c. to Hs.{Lord Ernest Hives - Chair} E1/M12.3.26. DOUBLE ACTING AUTOVAC. We have received from some English agents a patent specification and model of a double acting autovac tank originating from Germany. The model is well made and finished. It is built up where required of plated brass die forgings or castings, and is one taken apparently from manufactured stock. We attach herewith a blue print of Lec.2213 shewing a rough life size drawing of the actual model. DESCRIPTION. It will be seen that the two pumping chambers are concentric with a large float having a spring and ball mechanical bias in the central chamber. The weight of the float is just able to overcome the mechanical bias with certainty in the downward direction, and the buoyancy of the float overcomes the resistance offered in the upward direction. This float operates a double headed valve which throws the suction of the induction pipe (or mechanical pump) on to each chamber in turn. There is also an air inlet ball valve communicating with each pumping chamber which evidently operates automatically by suction when the suction valve is changed over, and opens each chamber to the atmosphere in turn. Each chamber is furnished with an inlet and outlet ball valve communicating with the leads to the fuel tank and carburetter respectively, so that when under suction the carburetter will be automatically cut off and when atmospheric pressure communication with the fuel tank will be automatically cutt off. The outer pumping chamber is also provided with a float and valve for cutting off the suction independently when this chamber is full of petrol. ADVANTAGES. (1) Since the apparatus is double acting in the sense that there are two cycles going on alternatively all the time, then the number of exhausted air and vapour charges receives by the induction pipe would be double in frequency, and contd :- | ||