1439666 Stuffing box substitutes NERATOOM BV 5 Sept 1973 41855/73 Heading F2B Sealing areas between the suction and delivery sides of a centrifugal pump impeller pumping liquids with abrasive consituents-, are shielded from the abrasive material by centrifugal means operating on liquid leaking through the areas, to eject the material in that liquid towards the delivery side. Leakage paths are formed between sleeves 11, 12 on the housing, Fig. 2, and sleeves 9, 10 on the impeller, the leakage liquid being set into rotation in annular channels 14, 21 which communicate with radial ducts 15, 22 through which the abrasives are ejected to the delivery side. In a more elaborate arrangement, Fig. 3, additional radial ducts 31, 39 open out at the periphery of the impeller and by-pass passages 32, 41 are provided in the housing sleeve portion 24, 34. The free axial end of the impeller sleeve 23 may have serrations, Figs. 4-6 (not shown) to give a preliminary swirling motion to fluid entering the leakage path 25. The seals may serve as bearings in the Fig. 3 arrangement.
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