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).
Water temperature thermometer made for motor car engines.
| Identifier | ExFiles\Box 40\1\ Scan069 | |
| Date | 30th October 1922 | |
| Report on WATER TEMPERATURE THERMOMETER made for Messrs. ROLLS-ROYCE, Ltd. RECD (30 OCT 22) ANS'D Summary. A sample Transmitting Thermometer suitable for indicating the temperature of the water in motor car engines has been made with a view to producing an instrument of greater reliability and accuracy than the vapour pressure types at present used. From tests made by Negretti & Zambra, it is apparent that in their mercury expansion type, errors due to change of the barometer, hysteresis, vibration, friction, backlash etc. are eliminated. The instrument has an evenly divided scale, and is graduated from 0º C so that in cold weather, when the engine is stationary the freezing points can be noted. Tests were made under actual running conditions, and it was evident the thermometer is more steady under vibration than the vapour pressure. The instrument is constructed in a more robust form than the vapour pressure type. (I) TYPES. Instrument No. T/1617. Rolls-Royce Dr.No.F.51965. Range 0/100º C. Divided every 2º, figured 0, 20 etc. to 100. Dial 2" aperture, black, labelled "Water" Bulb 10.5 mm. dia. x 63 mm. long. Capillary 5 ft. N.P. Weight 1 lb. 2 oz. Bourdon special. (1) Construction. The instrument is constructed on similar lines to the industrial Transmitting Thermometers described in N.& Z. List C.6., where the bulb is of steel and filled with mercury, and is connected to a Bourdon tube through compensated steel capillary tubing. The Bourdon tube is of special formation and operates direct on the axis of the pointer spindle, thus eliminating the quadrant, pinion, lever and hair spring usually fitted. The steel bulb is coated with a heavy deposit of purenickel of 1/100" thickness to prevent corrosion. The steel capillary is protected by well annealed copper tube hermetically sealed at both ends. (2) Tests. Comparative tests were made between the ether vapour type of water temperature thermometer supplied by Messrs. Robls-Royce and the following calibration tests were obtained:- Actual. N.& Z. Inst. No.T/1617. reads. Vapour Pressure Inst. No.29386 reads. up down up down 0º C. 0º C. 0º C. 10 10 10 Not reading below 50ºC. 20 20 20 on account of the low 30 30 30 vapour pressure of 40 40 40 ether. 50 49.9 49.9 50 51.2 60 59.9 59.9 60.7 61.5 ENCLOSURE Nº 252 "JUSTSO" | ||