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 to S. Smith & Sons, Ltd. regarding test results and requirements for a radiator Calorstat (thermostat).
| Identifier | ExFiles\Box 39\4\ Scan164 | |
| Date | 25th September 1930 | |
| X3499. Expl. Dept. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson}7/MJ. Sept. 25th.1930. Messrs. S. Smith & Sons, Ltd., Birmingham Works, 173-177, Clifton Road, Aston, BIRMINGHAM. Dear Sirs, Radiator Calorstats. We have now done a complete series of tests on the latest double-acting thermostat which you have supplied to us. We have succeeded in getting a standard freedom of radiator shutter which enables us to open the shutters with a load of 10 lbs. at the Calorstat and close them with a load of 5 lbs. at the Calorstat. With this degree of shutter freedom our shutters are fully open at a temperature of 63° to 65° on the road and closed at a temperature of 45° to 50°. The attached curve that we have taken of a thermostat is approximately what we should expect, allowing a small amount of friction for the bearing leverage etc. We want the shutters to be fully open at about 75°C., and fully closed at about 60°C. and though we can easily do this with a return spring we do not want to use this because Mr. Royce has taken exception to it, presumably because if the bellows punctures the shutters will be closed forcibly. We should like to know if you could supply us with a Calorstat with the liquid having a lower Vapour pressure which will give us this result without a return spring. We appreciate that this will mean that the slope on the closing side of the Calorstat curve will be steeper Cont'd.......... | ||