DURING the war the trend of tractor engine design toward increased efficiency resulted in many improvements and discoveries in accessories, not the least of which is the carbureter air-cleaner. The value of air-cleaners is now fully recognized and they are used as standard equipment on the majority of tractors.
Air-cleaners are classified into groups as follows: (a) cleaners having cloths or screens, or both, to catch dust; (b) inertia cleaners; (c) those employing water or some other liquid to trap dirt and (d) centrifugal or gravity cleaners.
The first class is practically obsolete; illustrations of two of this type are shown. Inertia cleaners are not widely used, but present possibilities. Liquid cleaners of various designs are in considerable use. The author believes that the slight advantage in efficiency of this type over the better class of dry-type cleaners is not sufficient to compensate for their greater size and difficulty of operation. Many wet-type cleaners are employed because the moisture they impart to the carbureter air is necessary on account of improper kerosene engine design. The operation of different forms of wet-type cleaners is illustrated and described. The centrifugal or gravity-type cleaner is most widely known and used. Its small size, simplicity, efficiency, ease of attachment, and the minimum care necessary for its efficient operation, commend it to the majority of tractor builders. An illustrated description of this type is given.