Threaded Impeller Locking Collar for Pump Thrust Retention
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Solution Overview
Problem
Centrifugal pumps face axial thrust forces due to unequal pressure distribution, leading to vibration, power loss, and reduced pump bearing life, with existing solutions either causing stress concentration or increasing complexity with custom machined parts.
Innovation Solution
An impeller locking collar system with threaded portions and a ring element, such as a split ring, is fitted around the shaft to mitigate axial thrust loads, using counter threads and set screws for anti-rotation and secure fitting, keeping the impeller in place without exposing components to fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If existing solutions are used to counter axial thrust forces, then axial thrust mitigation is achieved, but stress concentration occurs or device complexity increases with custom machined parts
Solution Approach 1:
The locking collar is divided into two separate portions: a first portion that fits around the shaft proximal to the impeller base, and a second portion that fits around the shaft distal to the impeller base. These portions are connected through threaded engagement, allowing the assembly to counter axial thrust forces while using standard, off-the-shelf components rather than custom-machined parts.
Solution Approach 2:
The first and second portions of the locking collar are nested around the shaft at different locations, with the first portion positioned proximal to the impeller base and the second portion positioned distal to it. The threaded connection between the portions creates a nested configuration that effectively distributes and counters axial thrust forces without requiring complex custom parts.
2Stability of the object's composition
If the impeller is secured against axial thrust forces, then impeller position stability is improved, but vibration-induced loosening may occur
Solution Approach 1:
The first and second portions of the locking collar utilize asymmetric threaded engagement, where the threads are configured to tighten the connection in response to vibrational forces. This asymmetric design ensures that vibrations during pump operation cause the portions to move toward each other, increasing the clamping force and preventing loosening, while still allowing for easy installation and disassembly.
3Productivity
If critical components are exposed to fluids being transferred by the impeller, then fluid dynamic performance may be affected, but component protection is reduced
Solution Approach 1:
The locking collar assembly (first portion, second portion, and ring element) is strategically positioned and configured to be removed or isolated from the fluid path. The components are located in positions where they do not interfere with the fluid being transferred by the impeller, thereby protecting them from fluid exposure (such as cavitation, erosion, or chemical corrosion) while maintaining optimal pump efficiency and fluid dynamic performance.
Data Source
AI summary
Technologies are generally described for holding an impeller of a pump assembly in place axially with an impeller locking collar by loading the collar against a ring element. In a centrifugal pump assembly, one side of the shaft has a larger diameter for the impeller to abut against. The other side of the shaft may be fitted with an impeller locking collar comprising two portions that can be threaded together and hold the impeller in place by tightening against a ring element such as a split ring or spiral lock. Anti-rotation to avoid loosening of the impeller locking collar may be achieved by providing counter threads against a shaft rotation. Secondary anti-rotation may be provided by one or more set screws in the impeller locking collar.