JAMES R ROBERTS, MD
Medical Practice at Ashley Ave, Charleston, SC

4174728, Nov 20, 1979

Nov 14, 1977

5/851330

George B. Usnick - Birmingham AL
Gene T. Ward - Sylacauga AL
Henry O. Blair - Sylacauga AL
James W. Roberts - Charlotte NC
Terry N. Warner - Wilsonville AL

The United States of America as represented by the United States
Department of Energy - Washington DC

F16K 320

137240

This invention is a novel valve of the slidable-gate type. The valve is designed especially for long-term use with highly abrasive slurries. The sealing surfaces of the gate are shielded by the valve seats when the valve is fully open or closed, and the gate-to-seat clearance is swept with an inflowing purge gas while the gate is in transit. A preferred form of the valve includes an annular valve body containing an annular seat assembly defining a flow channel. The seat assembly comprises a first seat ring which is slidably and sealably mounted in the body, and a second seat ring which is tightly fitted in the body. These rings cooperatively define an annular gap which, together with passages in the valve body, forms a guideway extending normal to the channel. A plate-type gate is mounted for reciprocation in the guideway between positions where a portion of the plate closes the channel and where a circular aperture in the gate is in register with the channel. The valve casing includes opposed chambers which extend outwardly from the body along the axis of the guideway to accommodate the end portions of the gate.