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).
Technical discussion on the design and implementation of a petrol gauge for a fuel tank.
| Identifier | ExFiles\Box 75\2\ scan0114 | |
| Date | 3rd February 1920 | |
| X3891. To R.{Sir Henry Royce} from Bn.{W.O. Bentley / Mr Barrington} Copy to PN.{Mr Northey} Copy to CJ. " " Ck.{Mr Clark} " " Da.{Bernard Day - Chassis Design} " " Hs.{Lord Ernest Hives - Chair} Bn{W.O. Bentley / Mr Barrington}10/W3.2.20. X.3882. X.3891. - RE PETROL GAUGE ON FUEL TANK. X.3451. (Due to head of Petrol) With reference to R1/G28/1/20. We note that the scheme sent through for a Petrol Gauge to mee the four conditions stated has been abandoned by you for the moment, and that we are to fit in the meantime the best gauge that can be purchased, we have arranged with Messrs. Sims to supply us with their standard vertical gauge which will be fitted near the centre of the tank, and will be calibrated to suit its section. This will be fitted in those cases in which customers request a gauge, but we do not propose to fit it as standard on every chassis. X.3891. With regard to the gauge which indicates the petrol level by recording the pressure due to the head of petrol in the tank, we will work on this as you suggest. One of the difficulties originally experienced with this scheme was that different people pumped at different rates and this gave a false reading owing to the resistance of the air pipe from the pump in the tank and in some cases the violent pumping ejected the indicating fluid out of the U. tube. This fault has now been overcome, I believe, by Messrs. Weymann of Paris, who have arranged the pump so that the Plunger is drawn by hand at any speed you like and is merely released when it is returned at a fairly constant rate by means of a spring. The pump is made large enough to give the maximum reading with one movement, of the plunger. My impression is that it was the practice to fit these indicators with a connection from the opposite leg of the U. type to the top of the tank in those cases in which an air pressure supply system was used. We could perhaps yse a simple plate release valve on the Plunger piston to prevent the violent operation of the pump interfering with the proper functioning of the indicator as the scheme adopted by Weymann's is not really a safeguard as it can still be mishandled. We take it that we shall utilise the existing hand pump with a two-way cock. In studying the design sent through which you have abandoned and bearing in mind Mr. Elliott's suggestion that that incorporation of a mirror might help us with simple central gauge, we came to the conclusion that any scheme incorporating a mirror would require artificial lighting by means of a small bulb with current taken from the rear lamp when it was required to ascertain the quantity of petrol in the tank. We have been over a number of ideas but have not found anything very good. In this condition it has occurred to us, however, that the common objection to making a petrol and air joint with a glass window might be overcome providing the window Contd. | ||