GB803871A - Improvements relating to seals between rotating and stationary parts of pumps - Google Patents

Abstract

803,871. Stuffing-box substitutes. GWYNNES PUMPS, Ltd. March 14, 1957 [March 16, 1956], No. 8279/56. Class 122 (5). A seal between the high-pressure and lowpressure zones 1, 2, Fig. 2, of a liquid pump, is provided by forming a clearance zone between a face 7 on one of two relatively-rotatable parts 12, 13 of the pump and a face 5 on a floating ring 6 which is mounted on the other of these parts and urged toward the face 7 by liquid pressure, liquid being permitted to flow to the clearance zone direct from the high-pressure zone and also under pressure through passage 10 of such constriction in the ring 6 as to result in a condition of balance of pressure acting on the ring with the discharge from the passages substantially limited to the amount necessary to prevent contact between the faces 5, 7. As shown in Fig. 2, the ring 6 is mounted on a support 4 fixed to the stationary casing 12 of a double-inlet centrifugal pump and coacts with the eye 3 of the impeller 13. Liquid can flow from the high-pressure zone 1 to the lowpressure zone 2, both directly between the opposed faces 5, 7 and also through the constricting passages 10 and a discharge cavity 9 in the ring 6 into the clearance zone. Fig. 4 shows an embodiment in which a pump suitable for pumping gritty liquids comprises floating rings 6, 61 on opposite sides of the impeller 13 to seal clearances between it and the stationary parts 12, 12<SP>1</SP>. The floating ring 6 is held against rotation by a pin 17 engaging a recess 18 in the pump casing 4, and a reduced portion 8 of the ring 6 is guided in an annular groove 14 supplied by ducts 15 with clean water which is at such pressure that it flows radially through the constricting passages 10, cavity 9 and the clearance zone to both high and low-pressure zones with the self-adjusting action described above. Secondary seals, to prevent the clean water leaking to the low-pressure zone without passing through the passages 10 in the ring 6, are provided by rubber packing rings 21, 21<SP>1</SP> which bear on the guide portions of the rings. Alternatively, the clean water may be supplied to the passages 10 through either a flexible tube arranged in the groove 14 or a bellows device. In a modification, the cavity 9 in the floating ring may be divided into two or more separate segments each in communication with a passage 10, or the ring may be divided into two or more self-adjusting parts. The Provisional Specification describes the seal as applicable between relatively-rotatable members generally.