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).
Appropriate coarseness of gauze for filters in carburettors to prevent choked petrol jets.
| Identifier | ExFiles\Box 135\2\ scan0069 | |
| Date | 24th August 1925 | |
| 13701 Rr. CC. c. Hs.{Lord Ernest Hives - Chair} BYL/H.{Arthur M. Hanbury - Head Complaints} 24.8.25. RE COARSE GAUZE IN FILTERS. - CARBURETTERS. ------------------------------------- It is evident that you have overlooked the fact that in R4/M.{Mr Moon / Mr Moore} 8.10.24. Petrol Filters on Aero and Other Engines, we were definitely instructed to make the gauze coarser. The wording of the memo is:- "The great point is that these small float chamber "filters should be fitted with suitable coarse "gauze about 30 per inch. Just sufficiently fine to "prevent choked petrol jet is all that is required." We did not go so far as the 30 mesh, as I thought that was too coarse, and instructed instead 50 per inch. Originally the 40/50 had no gauze at all in the jet, but the 20 HP. chassis was fitted with the 160 mesh wire gauze you refer to in your present memo. The complaint in regard to the 20 HP. carburetter was, we were in constant trouble owing to the gauze getting stopped up. It was in connection with such complaints that the recommendation referred to above was made. In dealing with this matter, I would liketo raise a point I intended to write about this week in any case. Since we have been using the vacuum feed we have unquestionably had considerably more trouble in regard to stopped jets than we ever experienced previously. So long as the 40/50 was not worked on the vacuum feed, when it was not fitted with a filter in the carburetter, we had very little trouble indeed with the 40/50 from this particular point, whilst at the same time under exactly similar conditions we were constantly in trouble with the 20 HP. We would like to suggest that possibly a settling chamber would be more effective if it were made of reasonable dimensions, than a gauze filter of any description, the petrol being brought in at the Contd. | ||