Gas seal for rotating grinding mill having peripheral discharge

A seal for a rotating mill having a rotatable cylindrical shell and a plurality of apertures arranged in a circumferential row, said seal comprising a first pair of spaced, parallel, planar, circular, rotatable ring members sealably attached to said shell with said circumferential row of apertures lying between said rotatable ring members, each of said rotatable ring members having a circumferential bearing surface at its side remote from said row of apertures, a fixedly mounted annular gas-tight seal housing member arranged around said row of apertures and said first pair of ring members, said housing member having a pair of spaced fixedly mounted ring members arranged adjacent said pair of rotatable ring members, each of said pair of fixedly mounted ring members having a first portion with a circumferential planar bearing surface in sliding contact with a bearing surface of an adjacent rotatable ring member and a second portion with a circumferential surface slightly spaced from said bearing surface of such adjacent rotatable ring member, each said first portion having a circumferential groove adjacent said second portion;

• a plurality of circumferentially spaced gas conduit means communicating with each of said grooves whereby gas introduced into said conduit means enters said grooves and passes between the second portions of said fixedly mounted ring members and the bearing surfaces of said rotatable ring members into said rotating cylindrical shell of said mill.