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).
Page 3 of a letter from The Packless Gland Co. Ltd. discussing bellows and mercury-filled devices.
| Identifier | ExFiles\Box 4\1\ 01-page053 | |
| Date | 30th April 1934 guessed | |
| - 3 - Messrs. Rolls-Royce Ltd. movement throughout the temperature scale unless relatively long bellows and spring are employed, as the rate of bellows is a variable factor and increases as the convolutions become closer together. A mercury filled device would, of course give absolutely linear motion, and in view of the enormous power available could be relied upon to be in any particular position at a certain temperature. Such a device could not, of course, employ bellows unless these were made of steel. Steel bellows are available, but owing to manufacturing difficulties are seldom constant in section, so that if these were used the object of employing mercury would to a large extent be defeated. Sufficient power might be obtainable from a steel Bourdon tube, but it would be necessary to house such mechanism in a petrol type container beneath a jet, so as to avoid the necessity for a gland which will certainly interfere with the satisfactory working of the apparatus. We shall be very pleased to do anything we can to assist you and look forward to hearing from you. Yours truly, THE PACKLESS GLAND CO. LTD. W. Martin-Hurst. Director. | ||