Centrifugal Pump Impeller Sealing for Abrasive Slurry Wear
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Solution Overview
Problem
Conventional slurry pumps face significant maintenance burdens due to wear caused by abrasive particles, particularly in the clearance between the throat bush and impeller, leading to frequent adjustments and increased downtime, and existing flushing mechanisms can cause slurry dilution and additional wear.
Innovation Solution
A centrifugal pump assembly with a shrouded impeller and a restrictor assembly that includes a fluid-activated restrictor body with adjustable fluid pressure, eliminating the need for a throat bush by sealing the space between the impeller and housing using a lantern-type ring restrictor assembly, which promotes even distribution of flushing fluid to prevent abrasive particle ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a throat bush is used to seal the clearance between impeller and housing, then sealing effectiveness is improved, but device complexity and wear susceptibility increase
Solution Approach 1:
The invention removes the throat bush component entirely from the pump assembly. Instead of using a separate throat bush to seal the clearance between the impeller and housing, the patent relies on the impeller shroud directly forming the sealing surface against the housing, thereby eliminating the throat bush and reducing component complexity while maintaining sealing effectiveness
Solution Approach 2:
The invention merges the sealing function previously performed by the throat bush into the impeller shroud structure itself. The impeller shroud is designed to directly contact and seal against the housing internal surface, combining the impeller and sealing functions into a single integrated component rather than using separate throat bush and impeller components
2Reliability
If flushing fluid is injected to prevent abrasive particle ingress, then component protection is improved, but slurry dilution increases
Solution Approach 1:
The invention introduces flushing fluid through restrictors before the abrasive particles can reach and damage the sealing surfaces. The restrictors are positioned to inject clean water into the clearance space between the impeller shroud and housing, creating a protective barrier that prevents particle ingress in advance, thereby protecting components without requiring excessive flushing fluid
Solution Approach 2:
The invention uses restrictors with specific aperture sizes and flow resistance characteristics to control the flushing fluid flow rate. By adjusting the restrictor parameters (aperture size, length, material), the system optimizes the balance between providing sufficient flushing protection and minimizing water addition to the slurry, thereby maintaining slurry concentration while protecting components
3Object-generated harmful factors
If conventional flushing mechanisms are used, then abrasive particle removal is improved, but additional wear and slurry dilution occur
Solution Approach 1:
The invention uses restrictors as intermediary components that control and direct the flushing fluid flow. These restrictors are positioned strategically to inject water at critical locations where abrasive particles threaten to cause wear, creating a controlled barrier that removes particles without the excessive fluid injection that causes dilution and additional wear
Solution Approach 2:
The invention applies flushing fluid locally at specific critical locations rather than throughout the entire pump. Restrictors are positioned to inject water precisely where the clearance between impeller shroud and housing is most vulnerable to particle ingress, providing targeted protection that minimizes overall water addition to the slurry while effectively preventing wear at critical points
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
This solution reduces wear on pump components, minimizes slurry dilution, and extends pump life by effectively sealing the impeller and housing interface, reducing maintenance needs and operational costs.
Implementation Method 1
a fluid-activated restrictor body, the body having a surface arranged for operatively sealing against an opposing surface of the annular conduit when rotating
Implementation Method 2
introducing a fluid for flushing (water)... for proper and effective lubrication
Implementation Method 3
promotes even distribution of flushing fluid to prevent abrasive particle ingress
Implementation Method 4
Centrifugal pump assembly comprising a housing having a suction side inlet and a fluid delivery outlet, a shrouded impeller rotatably mounted therein
Data Source
AI summary
In centrifugal pumps and, in particular, pumps for transferring fluids containing abrasive particles such as slurry pumps, wear of wetted areas is a major maintenance issue. The invention provides for the protection of internal surfaces vulnerable to wear from such particles by providing means for adjusting and controlling distribution of gland fluid for flushing vulnerable areas. The invention extends to a method and a retrofit kit, but provides primarily for a centrifugal pump assembly comprising an impeller rotatably mounted therein and support means operatively arranged for supporting the impeller from its suction side in sealing relationship with the housing. The sealing means may be mechanically adjustable for substantially even distribution of gland fluid to both axial sides of the impeller in the pump housing.