CENTRIFUGAL PUMP HAVING A PRELOADED LIP FOR SEALING THE SUCTION-SIDE RADIAL GAP BETWEEN IMPELLER SHROUD AND HOUSING

摘要

The invention relates to an arrangement for sealing a radial gap in a centrifugal pump, comprising a seal element which is made of a rigid main ring (1) and an annular elastic sealing lip (2) connected to the main ring and which is fixed to the inner contour (9) of the pump housing (8). A free end (3) of the sealing lip (2) slides along a sliding surface (7) during the operation of the centrifugal pump, said sliding surface being formed on the outer contour of an impeller (5), and the inner diameter (di) of the sealing lip (2) decreases at the sealing lip free end (3). According to the invention, the inner diameter is smaller at the free end (3) end face (4) facing away from the main ring (1) in the non-assembled state of the seal element than the outer diameter (Da) of the impeller (5) in the region of the sliding surface (7). A suction mouth (6) of the impeller (5) is slanted at the suction mouth end (11) in the direction of the suction mouth central axis (13) at an angle ranging from 15° to 45°. Over 25% to 75% of the length of the sealing lip (2) free end (3), which is pushed over the slanted region (10) onto the sliding surface (7) upon inserting the impeller (5) into the housing (8), rests against the sliding surface (7) during the operation of the centrifugal pump.