Method for providing axial gap in cutter assembly of grinder pump, and grinder pump comprising shim configured for providing said axial gap

Abstract

The invention relates to a method for providing an axial gap in a cutter assembly of a grinder pump in order to secure an operative shearing action at a shearing interface in said cutter assembly. Theinvention also relates to a grinder pump comprising a cutter wheel (5) connected to and driven in rotation by a drive shaft (16), the cutter wheel (5) comprising a set of cutting edges (13), and a cutter disc (6) stationary connected to a pump housing (3) and having a central hole (24) and a set of cutting holes (12), the drive shaft (16) and the cutter wheel (5) being interconnected via said central hole (24) of the cutter disc (6),wherein the cutter wheel (5) and the cutter disc (6) constitute said cutter assembly. The grinder pump is characterized in that a shim (27), that has a thicknessequal to or greater than 0,05 millimeters and equal to or less than 0,15 millimeters and that is manufactured from degradable paper or plastic material, is clamped between the cutter wheel (5) and thecutter disc (6), wherein the grinder pump further comprises a locking member (26) acting against the cutter wheel (5) and the drive shaft (16) and fixating the axial gap between the cutter wheel (5)and the cutter disc (6) provided by said shim (27), wherein the set of cutting holes (12) of the cutter disc (6) are located radially outside an imaginary circle that is concentric with an axial center axis of the grinder pump and that has a fourth diameter (D4),an outer diameter (Do) of the shim (27) being lesser than said fourth diameter (D4)of the imaginary circle of the cutter disc (6).

Description

technical field

[0001] The present invention generally relates to the field of pumps arranged for pumping liquids containing solid matter. Furthermore, the invention relates to the field of grinding pumps for pumping slurries such as wastewater. More specifically, the present invention relates to a method for providing axial clearance in the cutter assembly of such a grinding pump in order to ensure operational shearing action at the shear interface in said cutter assembly. The cutter assembly includes a cutter wheel and a cutter disc, wherein a shear interface is located between the cutter wheel and the cutter disc. According to the idea of ​​the invention, thin shims are used in the grinding pump to provide axial clearance in the cutter assembly to ensure operational shearing action at the shear interface in said cutter assembly of the grinding pump. Thus shims and lapping pumps are interrelated products of the same inventive concept that need to work together in order to ...

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