Reduction of volumetric loss in centrifugal pumps due to innovative balance hole arrangement

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Krzysztof Karaśkiewicz, Łukasz Złoty

    The large axial forces that arise in centrifugal pumps often cannot be completely balanced by bearings. In such
    cases, balance devices are used. One of the cheapest are balance holes. Their presence in the pump impeller is associated with
    leakage due to the pressure difference between the balance chamber and the impeller inlet. This leakage causes volumetric
    loss, ultimately diminishing the overall efficiency of the pump.
    Traditionally, balance holes have featured an axis parallel to that of the impeller. However, with the innovative skew of these
    holes, the pressure force difference between the inlet and outlet of the hole can be partially counteracted by the centrifugal
    force resulting from the rotation of the impeller and the corresponding inclination of the balance hole's axis. This novel
    approach holds the potential to reduce both leakage and volumetric loss.