Threaded Impeller Locking Collar for Axial Thrust Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Centrifugal pumps face axial thrust loads due to unequal pressure distribution across impeller shrouds, 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 or spiral lock, is used to secure the impeller axially, mitigating residual thrust loads and incorporating set screws for anti-rotation, ensuring the collar remains tightened during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If custom machined parts are used to counteract axial thrust, then the axial thrust load is mitigated, but the device complexity increases
Solution Approach 1:
The locking collar is divided into two separate portions: a first portion that engages the shaft and a second portion that engages the impeller. These portions are threaded together to form a complete locking mechanism. This segmentation allows each portion to be simpler in design while collectively addressing the axial thrust load without requiring complex custom-machined parts.
Solution Approach 2:
The second portion of the locking collar is positioned between the first portion and the shaft, creating a nested arrangement where components are housed within cavities of the pump casing. This nesting approach consolidates multiple functions into a compact structure, reducing overall device complexity while maintaining effectiveness in counteracting axial thrust.
2Reliability
If the locking collar components are exposed to fluids, then the impeller can be secured, but the risk of failure from solids increases
Solution Approach 1:
The locking collar components (first portion, second portion, and ring element) are strategically positioned within cavities of the pump casing that are distinct from the waterway cavity. This extraction removes the locking mechanism from direct exposure to the fluid stream and suspended solids, allowing the impeller to be securely held while protecting the locking components from harmful solid particles in the pumped fluid.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The impeller locking collar effectively maintains the impeller's axial position, reducing vibration and stress, enhancing pump reliability and life expectancy while avoiding exposure to fluids and potential failure from solids.
Implementation Method 1
The locking collar may include a first portion configured to be fitted around the shaft, the first portion comprising a first set of threads facing the shaft; a second portion configured to be fitted around the shaft and partially between the first portion and the shaft, the second portion comprising a second set of threads facing the first portion
Data Source
Figure 1
Figure 2
Figure 3
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.