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).
Analysis of the Smith's Calorstat for Phantom II radiator shutters, detailing operational effort and spring requirements.
| Identifier | ExFiles\Box 39\4\ Scan107 | |
| Date | 3rd April 1930 | |
| To E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/AJL. c. to Hy.{Tom Haldenby - Plant Engineer} c. to Rg.{Mr Rowledge} X3499 HS{Lord Ernest Hives - Chair}/AJL.1/AW.3.4.30. SMITH'S CALORSTAT FOR P.11. RADIATOR SHUTTERS. X3499 X7250 We give herewith curves showing the effort available from the Smith's Calorstat for temperature rise at various positions of shutter opening. The movement of the Calorstat from shutters fully closed to fully open is .325". The effort required to open the shutters against the mechanical friction in the mechanism on the one radiator (23-EX) at present available is 22 lbs. measured at the end of the small lever at which the Calorstat effort is applied. The Calorstat appears to have ample power in hand to do the job. It is necessary to find a suitable return spring for the shutters. The rating of the spring will depend upon the temperature at which it is required to open the shutters and the Calorstat effort available at that temperature. If we say that the shutters should commence to open at 75°C. and be fully open at 90°C, then from the attached curves the spring should be such that it exerts a pressure of 42 lbs. in the shutters closed position and 80 lbs. in the shutters fully open position, the effort being measured at the end of the small lever against which the Calorstat effort is applied. Tests which we have carried out on the Sylphon Thermostat indicate that this instrument is not sufficiently powerful to do the job. The maximum effort available at | ||