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 operation of an electrical petrol pump, focusing on pressure, the diaphragm, and current flow.
| Identifier | ExFiles\Box 91\2\ scan0099 | |
| Date | 9th July 1937 | |
| W/P - GWH.{George W. Hancock - Head Chateauroux} 300a 32-EX. Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems}10/JH.9.7.37. The petrol pumps are connected up as you state in your memo. The current does not flow through the coils of the dash pump although the higher pressure of the pump in the frame holds down the delivery valves and prevents it working. In an electrical petrol pump the points do not make unless the pressure drops allowing the diaphragm to move forward and the points to make. This draws the diaphragm back breaking the points and cutting off the current. As the pressure beyond the delivery valve is in excess of that which the dash pump will generate the diaphragm can not move forward and the points remain broken and no current flows. Hence the pump will not work except priming or if the pressure in the line falls below the pressure that the double pump can generate. Rm{William Robotham - Chief Engineer}/J.B.Dixon. | ||