Grinder Pump Shim for Axial Gap Control
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Solution Overview
Problem
Grinder pumps face issues with clogging due to improper axial clearance between the cutter wheel and cutter disc, leading to decreased performance and increased wear, which is skill-dependent and difficult to reproduce accurately during mounting.
Innovation Solution
A shim with a predetermined thickness is placed between the cutter wheel and cutter disc during assembly, clamped by a locking member to establish a reproducible axial gap, ensuring proper shearing action and reducing the risk of improper mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an adjustment screw is used to establish axial clearance between the cutter wheel and cutter disc, then the axial gap can be adjusted, but the mounting process becomes skill-dependent and difficult to reproduce accurately
Solution Approach 1:
The patent employs a disposable shim made of compressible material that is inserted between the cutter wheel and cutter disc during assembly. This shim provides the precise axial gap without requiring skillful adjustment, and is later discarded after serving its purpose of establishing the correct clearance. The shim replaces the need for complex adjustment mechanisms and eliminates skill-dependent mounting procedures.
Solution Approach 2:
The shim acts as an intermediary element that temporarily occupies the space between the cutter wheel and cutter disc to establish the correct axial gap. This intermediary component simplifies the assembly process by providing a predetermined clearance, making the mounting procedure straightforward and reproducible without requiring operator skill.
2Ease of operation
If the axial gap between cutter wheel and cutter disc is too big, then assembly is easier, but solid matter accumulates and clogs the interface leading to decreased performance
Solution Approach 1:
The disposable shim provides a controlled axial gap during assembly that prevents excessive clearance, thereby avoiding solid matter accumulation and clogging. After serving its purpose of establishing the correct gap, the shim is discarded, leaving the cutter assembly ready for operation with optimal clearance that maintains high productivity.
3Ease of manufacture
If the axial gap is not accurate, then mounting is simpler, but excessive wear occurs on the cutter disc and increased friction reduces performance
Solution Approach 1:
The shim provides a predetermined accurate axial gap during assembly, eliminating the need for complex adjustment procedures. This ensures proper clearance that prevents excessive wear on the cutter disc and minimizes friction, thereby maintaining cutter assembly reliability while keeping the mounting process simple.
Data Source
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AI summary
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. The invention also relates to a shim suitable for providing said axial gap and a grinder pump () comprising such a shim. The grinder pump comprises 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 thickness equal 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 the cutter 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).