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 memorandum discussing fuel tank venting arrangements and gauge head markings.
| Identifier | ExFiles\Box 61\3\ scan0146 | |
| Date | 17th December 1930 | |
| Messrs. Rolls-Royce, Ltd., Date 17.12.30. Page 2 venting arrangement; the bell venting arrangement naturally working in concurrence. It must be remembered however that the vent tube discharges some inches above the last gallon. The rise of the liquid in the gauge, coupled to the circuit, above the height at which the vent tube discharges was negligible, and well within the factor of safety, so that it may be assumed that the set is proof against plus pressures up to the quite unusual figure of 8 lbs. to the square inch, and that negative pressures, owing to the ample venting arrange-ments, will be adequately provided for. It is not possible to estimate exactly from the drawing the amount of clearance which the extreme lower edge of the dome will have around the turret on the tank, upon which the tank unit is fixed. The annulus should be of such an area as not to restrict the venting or overflow requirements. (2). The marking of the gauge head. Our usual practice in the marking of any gauge head is not to show on the dial the last ½ to ¾ of gallon which the tank can hold. By this means the disadvantage of any over-night loss which may occur is practically eliminated in all instances. We have found that the disadvantage of the over-night loss becomes apparent when the tank is filled by a user by calculation in the garage before the car is moved. For example, | ||