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).
Promotional and informational leaflet from the Air-Maze Corporation about their automotive air filters.
| Identifier | ExFiles\Box 135\4\ scan0093 | |
| Date | 8th February 1926 guessed | |
| only a partial cleaning job is needed, viz.: In wood working plants, sand blast purposes, and similar use where only a rough extraction is required. You now have the “What,” “How” and “Why” of Air Cleaners for Motor Cars, and are in a position to make an intelligent choice when you come to purchase a car, already equipped, or buy a cleaner for your present car. We believe, however, that you will choose a Filter Cleaner rather than a Whirler, and we naturally hope that your choice will be the Air-Maze. The Air-Maze Corporation guarantees you perfect satisfaction when you buy an Air-Maze filter; and I will personally guarantee, in addition, that you will feel the money you spend for an Air-Maze is about the best outlay you ever made of an automobile accessory, and will save its cost several times over in the course of the year on lubricating oil alone. O.{Mr Oldham} V.{VIENNA} GREENE. Printed for distribution by Air-Maze Corporation 1629 Union Trust Building Cleveland, Ohio When you pull out your choke in starting your car, you increase the resistance to the air flow into the carburetor, and cut down the air volume, and at the same time you increase the fuel flow—which facilitates starting. Now, if our whirler cleaner is properly designed, the air stream entering the cleaner will be very thin—probably not over an eighth of an inch thick, and the circumferential velocity will be in the neighborhood of ten thousand feet per minute. Of course such a design means quite a bulky affair, so some of the manufacturers of the whirler types resort to a compromise for the sake of size and make their air stream a half an inch or more thick, with resulting lower efficiency, and a slightly lower resistance. Anyway, you can get an idea of the very large resistance set up at the carburetor intake, in a well designed whirler, by dividing 10,000² by 4000² and multiplying by .60, which gives us 3.76 ounces—just 2.78 times greater than the normal carburetor resistance. It will be readily appreciated that there must be some sort of a change in the carburetor to compensate for this abnormal resistance, and this change usually takes the form of a reduction of the fuel passages in the carburetor. In other words, if you partially close the choke on your car, you’ll get the same effect as the whirler cleaner produces, with the attendant increase of unburned gasoline to mix with—and dilute your lubricating oil. So much for why a whirler cleaner requires a recalibration or readjustment of the gas flow, to “lean down” the mixture, because of the increased draw of this type. This means that the power-performance range is greatly narrowed. Now for the filter type—particularly Air-Maze. There are several sizes of Air-Maze filters to take care of different size engines—from the largest to the smallest. The filter area for each size Air-Maze is so calculated that the maximum actual velocity passing through the filter shall not exceed eight hundred feet per minute (a speed about as fast as a good trot) at maximum engine speed. This means that the resistance to the flow | ||