Combine harvester with variable output fan

摘要

The harvester incorporates cutting and feed mechanisms for the crop, together with a threshing mechanism whose concave pref. extends in the travel direction. The fan is mounted before or below the sieve mechanism. The speed of the fan (12) is adjusted dependent on a value, e.g. air speed or pressure, generated by it, typically to an ideal predetermined value dependent on the type of crop and by the driver. Any variation from the desired value can be detected and the speed altered until the variation is within predetermined limits. Variation in the value generated can be detected by a sensor, which emits the appropriate control signal.