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).
Design flaws in Exide hydrometers following a comparative test.
| Identifier | ExFiles\Box 44\5\ Scan074 | |
| Date | 19th May 1924 | |
| To BY/C. from EFC. EFC4/T19.5.24. X3741 X.3741 - EXIDE HYDROMETERS. With reference to the two Exide hydrometers which you handed to us for comparative test, please find attached copy of my assistant's report JB.45. It will be seen from this report that we think the new type is an improvement generally. It appears to us, however, to be an error that the float jams in the narrow part of the neck in the middle of the glass tube. So long as the float jams at this point, the good point referred to in (1) on the attached report, of preventing the float not coming into contact with the top of the glass barrel, does not hold. Another thing, which it is sometimes a nuisance to un-jam the float when it sticks at this point. Presumably the advantage of the narrow parallel bore (where the word 'Exide' is written) is that you get a better head of liquid, otherwise we do not see why the tube should not be made of diameter at this point equivalent to that of the rubber fitting, so that only one change of section (and that a small one) occurs in the tube. We feel that as it is, there is a great tendency for the tube to break at the change of section, especially as the inside bore is actually smaller at this point. On examination there is an ominous line down the tube at this point which though not perhaps actually a crack, is very suggestive of one. EFC. Contd. | ||