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).
Explaining the features and advantages of the Air-Maze filter compared to other types.
| Identifier | ExFiles\Box 135\4\ scan0095 | |
| Date | 8th February 1926 guessed | |
| The resistance of the different filter cleaners varies over a wide range; the felt filters restricting the most in this respect, and requiring readjustment of the carburetor fuel supply in order to operate with reasonable satisfaction. And now to re-state and emphasize some of the features of the Air-Maze filter, as representing the highest attainment in its field in removing practically 100% of all dust from the air entering an automobile motor: In the first place, as previously indicated, Air-Maze imposes no practical restriction on the carburetor performance, and thus conserves the full horsepower of the engine, and it does not increase the normal dilution of the lubricating oil, in fact by reducing the wear on the piston rings, occasioned by the dirt in the air, this dilution is minimized in the long run. Every Air-Maze, when properly fitted to the car, is guaranteed to remove at least 97% of atmospheric dust from the air at all engine speeds. The mere fact that you can see just what kind of a cleaning job the Air-Maze is doing all of the time, is an advantage possessed by no other cleaner on the market. You look at the dirt accumulation on the outside of the filters, dirt which would have otherwise gone into your engine, and then, by removing the filter from its support, you see absolutely no dirt on the inside of the filter. It takes away all of the guess work as to whether your cleaner is doing its work properly. The question has been raised by people who have not actually tested the Air-Maze on a motor car—and you may ask the same question, to-wit: “Why doesn’t the filter plug if it catches the dirt?” The answer is: that it probably would if you never touched it during the life of the car, or say for 100,000 miles or so. But under normal operating conditions, over a season’s run, the filter does not plug, or even accumulate a reasonable restriction, because of its very large dust carrying capacity, as previously indicated. This dust carry- made with these, or any other 100% material, would not show the practical efficiency of any cleaner. THE ONLY WAY IS TO MAKE A TEST ON A MOTOR CAR IN ACTUAL OPERATING CONDITIONS ON THE ROAD. Under such practical conditions, Air-Maze shows an efficiency of as near 100% as it is possible to get without imposing a filtering medium of prohibitive resistance to the carburetor intake. A misconception is common with regard to the filter type of cleaner; whether screen, cloth or some other material is used in the cleaner. This misconception is to the effect that all such devices act as strainers, i. e.{Mr Elliott - Chief Engineer}, that the opening in the media is smaller than the dust particles collected. This is not so, as will be readily apparent by looking—for instance—at the very large mesh openings of the screen used in the Air-Maze filter—a mesh which is almost identical with the screen you use over your windows in the summer time. You might say that a felt filter was an exception to this statement; but this likewise is wrong, because if you look at the matted threads of the felt, through a good magnifying glass, you will see that the threads are separated a distance considerably greater than the size of the particle of dust collected. There is this difference, however, in the two examples, viz.: while the screen has a good 60% mesh opening, the felt is less than a tenth of this percentage, which accounts for the fact that felt filters have to employ a very large area in order to get within shooting distance of a permissible restriction factor, and they are consequently bulky and cumbersome. All filter cleaners work on what is known as the “baffling impingement” principle; the same principle which operates to keep the dust out of your head and lungs—the dust impinging against and being held by the hairs in your nostrils. It is the most natural and effective principle known, when properly applied, for removing fine dust particles from air or gas. Oil is used to coat the screen wires of the Air-Maze, to increase the dust collecting ability of the filter, on the same basis that the hairs in your | ||