File:NIE 1905 Flour - older flour-mill.jpg

English: Section of an older form of flour mill. The millstones are at a, the lower of which is firmly fixed, and the upper is made to revolve, on a shaft which passes up through the lower one, at a speed of one hundred revolutions per minute, more or less. Motion is communicated by the spur-wheel b, which is driven by a water-wheel or other power. The grain, previously cleaned, is supplied to the millstones by means of the hopper, c, connected with which there is a valve, d, for regulating the supply. Passing through a hole in the centre of the upper millstone, it comes in between the two, where it is ground, and thrown out on all sides by means of the centrifugal force. The millstones are, of course, inclosed, and the flour passes down through the spout, e, to the worm at f, which carries it along to elevators, g. These raise it up to the floor, on which the dressing-machine, h, is placed. This is a cylinder, which was formerly made of wire-cloth of various degrees of fineness, and consequently separated the flour into different qualities, but no part of it large enough in the openings to let through the bran, which passed out at the end. Silk is now preferred to wire-cloth for dressing the flour. Hoppers, i, are placed below the dressing-machine, by means of which the flour and bran are filled into sacks; No. 1 being fine flour; No. 2, seconds; and No. 3, bran.