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 from The Chloride Electrical Storage Co. Ltd. regarding design modifications to the Exide Type S.1 Hydrometer.
| Identifier | ExFiles\Box 44\5\ Scan100 | |
| Date | 7th February 1928 | |
| EFC XJ741 COPY THE CHLORIDE ELECTRICAL STORAGE CO.,LTD., CLIFTON JUNCTION, NR. MANCHESTER. ECM/LJ. Messrs.Rolls-Royce, Ltd., DERBY. 7th February, 1928. Dear Sirs, re Exide Type S.1 Hydrometer. We beg to acknowledge receipt of your letter refer-ence BY/MtnS/K 6.2.28 of the 6th instant, and are glad that you have raised the point regarding modification in design of the hydrometers with us, as it gives us the opportunity of bringing to your notice the advantages of the latest design. These might otherwise not have been apparent. As you point out, the provision of spikes on the float was to prevent the float sticking to the sides of the hydrometer barrel, but it was found that to prevent the stem of the float from clinging to the sides of the barrel it was necessary to work with extremely fine tolerances and the amount of electrolyte was thereby restricted. There was consequently a lag in obtaining a quick reading, apart from the trouble through the stem clinging to the sides. In the new design we have dispensed with the spikes and have made the barrel slightly top-or carrot-shaped. This enables us to employ more acid in the portion where the hydro-meter floats, and appreciably increases the distance from the stem of the hydrometer to the wall of the barrel. Yours faithfully, THE CHLORIDE ELECTRICAL STORAGE COMPANY, LTD. (Sgd) E.C.McKinnon Chief Engineer. | ||