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).
The development and testing of a water level indicator for an aircraft engine header tank.
| Identifier | ExFiles\Box 179\2\ img011 | |
| Date | 31th December 1931 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Cib. C. EG. MOR. C. EG. S. C. EV.{Ivan Evernden - coachwork} L. EVAPORATIVE COOLING. X4520 WATER LEVEL INDICATOR FOR HEADER TANK. A device has been developed in conjunction with evaporative cooling to be fitted to the header tank, which in the event of a water leak entailing a considerable water loss, warning is given to the pilot by means of a light that the water in the header tank has reached a very low level. Its various application was dealt with and circulated by Lr.{Mr Ellor} in LRL/AM.4.10.31 Water loss indicators on cooling systems in aircraft. Description. The bi-metal scheme DES.1573 is fitted into a "bottle" (as used for the standard transmitting thermometers) and is mounted outside on the top of the tank (see sketch). From the "bottle" two pipes lead into the tank, one pipe is used for defining the minimum water level. When the water level falls below the open end of this pipe steam passes up and around the electrical unit. The end of the second pipe is arranged in the tank outlet pipe mouth so that a slight depression is created just great enough to assist the steam flow around the bottle, but not great enough to lift the water when running normally. Tests Results. The unit was fitted on the R.R. tank and tested under various conditions. The engine was run until the water boiled, then the water was run off the tank until the level fell below the bottom of the indicator pipe and the final setting was arranged so that there was 1 gall. of water left in the header tank when the warning was given, the quantity lost being 2 galls. During the development we found that the scheme was very sensitive to indicator pipe sizes but the final unit was made successful on the test rig with pressures in the tank varying from 1/4 to 2 1/4 lbs/sq.in. The successful operation of the device depends on the following :- (1) Using the correct size of pipe. (2) Having the correct size of holes at the bottom of the ejector pipe, as one effects the other if not correct. | ||