Modern Flour Mill
This illustration shows a cross-section of a modern flour mill. Wheat is received in bin a, and first passes to the separator b, where it falls over vibrating screens, c, c, and a current of air draws light rubbish through pipe e to fan d. Next, in scourer f, it passes through revolving beaters, and meets a current of air. In the brush g, revolving brushes further clean and polish the wheat, which then passes to the ‘cylinder’ h. This revolving cylinder has grooves which pick up any small seeds, carrying them around until near the top of its revolution they drop into trough k and discharge by l at n, while the wheat grains too large for the grooving to affect, fall into the trough m, and are carried by the elevator p to the ‘first break rolls’, o. Here the wheat is partly crushed by rolls q, q, and passed to the ‘scalper’ r. Here, revolving brushes and beaters force the small particles through the fixed cage to the shoot s, while the larger are delivered at the end of the cage and pass to the second pair of rolls, t, and the second scalper, u. The coarse particles from u, chiefly bran, pass through a third set of rolls, v, and then to the ‘bran duster’, w, a cylinder where revolving brushes clean all flour from the bran and force it through perforations towards shoot x, the bran being delivered at y. The flour is carried by elevator p’ to the ‘reel’ z, a finely perforated cylinder which revolves rapidly, an the finer part passes by shoot s’ to the ‘centrifugal’ u’; the coarser part delivered at the end of the cylinder, passes to the ‘purifier’ r’, where a current of air removes light dust as it travels over a moving sieve, and thence to a set of rolls at t’ for further reduction, after which it is delivered to the centrifugal u’. This is a revolving drum, covered with silk, through which the flour is thrown by centrifugal force, and is delivered finished at v’, the offals passing out at the end of the drum to the shoot w’.
John H. Finley ed. Nelson's Perpetual Loose-Leaf Encyclopaedia (vol. 5) (New York, NY: Thomas Nelson and Sons, 1917)