The structure and effjciency of several Japanese threshers. : II. Notes on the winnowing mechanism

From the investigation here described the writer confirmed that the efficiency of Japanese threshers remarkably influenced by the winnowing mechanism. The experiments have been done at the same time as described in the Report 1 ”Notes on the cylinder”. The winnowing apparatus or the cleaning device to cleanse the grains from the impurities of Japanese threshers consists of four main parts, viz.the shoe （to slide down the grains along it into the current of air）,the fan （extending across the entire width of the machine and sending the equal draft of air through all parts of the winnowing,apparatus）,the sieve（to cleanse the grains from the impurities）and the air control device（the doors or openings）. To have a good efficiency of the threshing the careful adjustment of the winnowing apparatus should be done in respeet of the amount of air used,the size of the doors at each side of the fan housing the number of revolution of the fan, etc. The high velocity of the air current and even blast of air against all the under-surface of the shoe－shieve is to be got by the adjustment above described. 1.The velocity of the air current is rather increased by higher speed of rotation than the larger size of tne fan. 2.The size of the doors must be held as large as possible and they must be open equally. If they are too small,the amount of air decreases on the middle part of the alr current, and if they are not open equally, it decreases on the closing side of the doors.ln this case the mean revocity of the air current is low. 3.when the number of revolutions and the size of fan are small,it is disadvantageous to have wide width of the air currcnt.lf the width is yery large, the low velocity and the uneaven blast of air occurr. 4.1n order to obtain the high velocity of the air current,it is necessary to make....