Submersible Semi-Axial Centrifugal Pump

A submersible semi-axial centrifugal pump for installation in a column and configured for pumping liquid comprising solid matter, comprising:

• an outer pump housing having an axial inlet and an axial outlet, and
• an inner pump core arrangement, comprising:
• a stationary drive unit surrounded at least partly by the pump housing,
• a semi-axial open centrifugal impeller that is suspended from the drive unit and located adjacent the inlet of the pump housing, and
• a plurality of guide vanes extending between and connecting the pump housing and the drive unit of the pump core arrangement,
• wherein the impeller comprises a hub and at least two spirally swept blades connected to the hub and extending in the radial direction from the hub, wherein the hub is essentially cone-shaped tapering towards the inlet of the pump housing, each blade comprising a leading edge facing the inlet of the pump housing, a trailing edge facing the outlet of the pump housing and a lower edge,
• wherein the lower edge extends from the leading edge to the trailing edge, wherein the outer pump housing comprises:
• a diffuser, connected to the stationary drive unit via the radially extending guide vanes, wherein the diffuser comprises the outlet of the pump, and
• an inlet funnel, fixedly connected to the diffuser, wherein the inlet funnel comprises the inlet of the pump,
• wherein the semi-axial centrifugal pump comprises a pump housing liner, located between the outer pump housing and the lower edge of the impeller, wherein the pump housing liner is displaceable in the axial direction in relation to the outer pump housing in order to adjust a radial gap between the pump housing liner and the lower edge of the impeller,
• wherein the pump housing liner comprises a radially extending flange and the diffuser comprises a transversal surface located opposite said radially extending flange,
• the pump housing liner being displaceable in the axial direction in relation to the outer pump housing by means of axially adjustable attachment means that are in threaded engagement with the diffusor at the transversal surface and that are accessible and manipulatable via openings in the inlet funnel,
• the adjustable attachment means comprising a plurality of adjustment screws and a plurality of locking screws, wherein the radially extending flange is clamped between the head of the adjustment screws and the head of the locking screws,
• wherein the maximum distance between the transversal surface and the radially extending flange is defined by the locking screws, and
• wherein the minimum distance between the transversal surface and the radially extending flange is defined by the adjustment screws.