GB535087A - Improvements in or relating to wind-swept grinding or pulverising mills - Google Patents

Abstract

535,087. Ball &c. grinding mills. NEWELL & CO., Ltd., E., and HOWDEN, P. Nov. 8, 1939, No. 29623. [Class 59] In wind-swept grinding mills of the type comprising a rotary ball &c. containing drum partitioned transversely to form a primary grinding chamber 3 and one or more co-axial classifier chambers 4, the material to be reduced being introduced into the grinding chamber through a hollow trunnion 7 at one end of the drum and the reduced material being carried through a hollow trunnion 8 at the other end of the drum by a current of air flowing through the drum, a straight conduit 15 is connected to the trunnion 7, a fan 19 is connected to the conduit, a feed shoot 24 is connected to the oonduit between the fan and the hollow trunnion, a separator 28 is connected to the trunnion 8 and an air pipe 29 connects the separator to the inlet of the fan. The feed shoot 24 extends obliquely, as at 25, into the conduit to set up venturi action therein The chamber 3 is separated from the chamber 4 by an annular baffle 1'2 having one or more passages therethrough at or near the axis and away from the periphery. The entry to the trunnion 8 from the chamber 4 is screened by a conical baffle 13. The shoot 24 receives material from a rotary valve 23 below a conveyer 22 and feed hopper 21. A second feed shoot 33 may be used as an alternative to or in addition to the shoot 4. According to the Provisional Specification, instead of the classifier chambers being provided with ball &c. grinding elements those chambers may be fitted with means for conveying material deposited therein back to the primary grinding chamber.