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).
Analysis of foreign matter causing choked jets and a comparative test of different filters.
| Identifier | ExFiles\Box 44\1\ Scan110 | |
| Date | 22th September 1929 guessed | |
| contd :- -2- to .0055" square. Therefore particles large enough to obstruct the jet can pass this gauze. (c) Foreign matter causing choked jets. We examined a specimen of fluff actually extracted by Sales from a choked jet. This type of 'fluff' appears by common consent to be the chief cause of trouble at present being encountered. Under the microscope we observed that it consisted of a number of fine hairs varying from .0005" to .003" in dia. in lengths up to .125". The texture could be approximately reproduced by shredding an ordinary felt hat. (d) Zenith filter. This filter appears to be the most promising of any of the tyres at present on the market. It consists of about 50 brass rings assembled in a cage. The cage allows sufficient movement when unscrewed for the filter to be cleaned. The mesh of the filter is provided by the plates which are manufactured with small protuberances on their faces. When tightened up in position, the gap between the plates is .0017" and the distance between different plates is held very consistently. The filtering 'cartridge' is surrounded with a glass bowl, which, as the petrol is fed in from the outside, acts as a settling chamber for dirt and water (see sketch). (e) Comparative test - RR. and Zenith filter. We carried out a comparative test feeding petrol heavily impregnated with a mixture of grit and fluff, through these filters and then through a 40/50 low speed jet. In both cases the filters became completely choked before the low speed jets, the latter however collected a certain -- contd :- | ||