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).
Letter discussing the simplification and modification of a gauge and tank unit design.
| Identifier | ExFiles\Box 61\3\ scan0072 | |
| Date | 4th July 1930 | |
| Messrs. Rolls-Royce Ltd., Date 4/7/30. Page 2. as you outline on page 2 of your letter. The necessity for a reservoir, we would submit, will be entirely unnecessary, the reason for this being that with the modified design of tank unit incorporating the small hole in the bell plate and the bell vent tube discharging into the tank vent, both discharging to atmosphere, it is an impossibility for the liquid in the gauge to rise more than 10% above the height of the shimming head, i.e., from datum to height of vent in the tank. Needless to say, we are very pleased indeed to think that the gauge is to be simplified by the abolition of the pressure balance line and pump line, and we have every confidence that we can make up an arrangement which will give infinitely less trouble in installation and service, besides being more economical and practical. For the gauge head we would suggest the following as being absolutely adequate to the situation, and which you can prove yourselves by tests:- In the existing body reduce the scale in the front glass from 2 1/8" to 1 7/8". This will leave more than sufficient glass tube above the scale to provide a safety factor now that we have a bell vent discharging into the tank vent and so to atmosphere, say 1 1/2" above the top of the tank and top of filler. The back tube will extend 1 1/2" below the frame, or 1 5/8" below the body of the gauge. | ||