Sump Pump Impeller and Strainer Layout for Slurry Solids Handling
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Solution Overview
Problem
Conventional sump pumps in mining applications face issues with particle buildup in the sump and pump housing, leading to jamming and early failure, as well as reduced flow rates when trying to prevent particle ingress, which can result in overflow.
Innovation Solution
The design incorporates an impeller with inducer elements and flow generating elements that assist in lifting and removing particulate matter, along with a flow directing device that creates a recirculating flow to disturb settled solids and a pump casing with flow distribution vanes to enhance slurry delivery, addressing the issues of particle buildup and flow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strainers are provided at pump inlets to prevent large particulate matter ingress, then impeller damage is reduced, but flow rate is limited which can result in sump overflow
Solution Approach 1:
The pump system is segmented into multiple functional zones: strainers for particle filtration, inducer elements for particle lifting, and pumping vanes for slurry transport. This segmentation allows each component to specialize in one function, enabling the strainers to protect the impeller while other components maintain high flow rates.
Solution Approach 2:
Inducer elements act as intermediary components between the strainers and the main impeller. These elements lift settled particles into the slurry flow before they reach the impeller, preventing particle buildup and jamming while maintaining unrestricted flow through the strainers.
2Reliability
If agitators are provided in the sump pit to prevent particle settlement, then particle buildup is reduced, but agitators wear rapidly which diminishes their efficiency
Solution Approach 1:
The pump system performs self-agitation through its normal operation. The inducer elements and recirculating flow pattern create continuous movement in the sump pit that prevents particle settlement without requiring separate agitator mechanisms, thereby eliminating wear issues while maintaining particle suspension.
Solution Approach 2:
The pump system serves multiple functions simultaneously: it pumps slurry while also agitating the sump contents to prevent particle settlement. The same rotating components that move slurry also create the recirculating flow that keeps particles suspended, eliminating the need for dedicated agitators.
3Reliability
If the lower pump inlet is closed off to prevent particle jamming, then impeller rotation is protected, but flow capacity is reduced which may cause sump overflow
Solution Approach 1:
The harmful function of the lower inlet (particle jamming) is extracted and separated from the useful function (flow intake). The lower inlet is modified to include strainers and inducer elements that remove the jamming risk while preserving the flow capacity, allowing both inlets to remain open for maximum flow.
Solution Approach 2:
Different regions of the pump inlet system are given different functional qualities: strainers are placed at critical locations to filter particles, inducer elements are positioned to lift particles in specific flow zones, and pumping vanes are designed for optimal slurry transport. This local differentiation allows each area to address specific problems without compromising overall flow capacity.
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 solution effectively clears settled solids from the sump pit, reduces wear on agitators, and maintains flow rates by using inducer and flow generating elements to lift and remove particles, and the flow directing device to ensure efficient slurry handling, thereby extending the life of the pump and preventing overflow.
Implementation Method 1
an impeller having a rotational axis and including: a hub, a back shroud extending from the hub, and a front shroud, wherein each of the shrouds has an inner surface and an outer surface, the impeller also having: a plurality of pumping vanes extending between the respective inner surfaces of the shrouds, and an impeller inlet opening in the front shroud coaxial with the rotation axis of the impeller, wherein the impeller includes one or more inducer elements which extend from the inner surface of the front shroud towards the rotation axis and which are positioned adjacent the impeller inlet opening
Implementation Method 2
a flow directing device that creates a recirculating flow to disturb settled solids and a pump casing with flow distribution vanes to enhance slurry delivery
Data Source
AI summary
A pump assembly and components therefor including an impeller which has flow inducer elements on an inner surface of a front shroud thereof, a flow directing device or strainer having passageways for delivering material to the impeller and at least one flow circulating passageway and a pump casing having an intake section with flow distribution vanes in the region of a feed opening adjacent the intake section.