Fanner / Ethnography

Before the mill was built, the method of cleaning threshed grain was to toss it in a light wind. The heavier grain fell faster than the lighter chaff which was blown away by the wind. Sieves were used to separate other impurities from the grain.

The hand-operated fanner consisted of a wooden casing forming a ventilation channel and a centrifugal fan casing made of several flat blades and a set of moving screens. A cranked fan directed air into the duct. Above the venting canal, there was a box for the grain that had an adjustable slot through which threshed grain with chaff poured into the canal.

The cleaned grain, falling into the channel, fell on the upper sieves and was simultaneously blown away by the wind generated by the fan. The upper sieves separated the larger debris and the fan then blew away the chaff and lighter waste material. The grain was separated from finer impurities on the lower sieves. In simple constructions, only one upper sieve and one lower sieve were used, though complex versions could have several sieves.