GB529518A - Improvements relating to the milling of wheat flour - Google Patents

Abstract

529,518. Sifting-apparatus. SIMON, Ltd.; H.. and LOCKWOOD, J. F. May 20, 1939, No. 15081. [Class 117] [Also in Group I] In the milling of wheat flour the first throughs of the scalping screens of the first and second break roller mills a, b, said throughs consisting of chipped endosperm, cut-up bran and cut-up germ, are passed through a purifier or sifter h of which the throughs are reduced in a finely fluted scratch roller mill i whereupon the finer material is sieved out as at j and the overtails treated for separation of the germ from the lighter material by air flotation in an aspirator k using a large volume of air having a velocity of 380-440 feet per minute, the germ being thus recovered, as at m. Also, the first overtails of the scalping screens of the second break roller mill b are passed through the third break roller mill c and then the stock, which passes through a No. 16 fine wire screen and over a finer screen, as at f, for the separation of the finer material is treated for the separation of the germ from the lighter material by air flotation in an aspirator g using a large volume of air having a velocity of 380-440 feet per minute, the germ being thus recovered. As a purifier the part h has a screening cover which allows stock finer than the overtails of a 14 fine wire gauze to pass ; as a sifter it has a 20 fine wire gauze screening cover. In the aspirator the material is preferably subjected to successive aspirations of gradually increasing intensity within the airvelocity range above referred to ; thus, as shown in Fig. 2, material introduced by the duct n is transferred by a roller s to a duct p up which is passing 'aspirating air, and from the duct p the material is transferred in succession to further ducts q, r, up which further currents of aspirating air are travelling. The separated germ leaves at o.