Centrifugal Pump Volute Channels for Solid Shedding
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Solution Overview
Problem
Centrifugal grinder pumps face issues with solid material accumulation on the impeller, seal damage from foreign materials, and inefficiency due to friction and energy consumption, along with high manufacturing and assembly costs.
Innovation Solution
The design includes a rotary impeller with radially extending vanes and a volute with channels that prevent solid material accumulation, a unitary pump volute for reduced assembly costs, and a seal placement that maintains lubrication and protection from solids, along with a cutting assembly that reduces energy consumption through minimized friction and drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long record grooves are formed in the volute base surface to prevent solid material accumulation, then solid material shedding is improved, but the effectiveness is limited for certain types of solid materials
Solution Approach 1:
The volute base surface is segmented into multiple radial channels instead of a single continuous record groove. Each channel is bounded by land portions that create discrete pathways for solid material to be shed. This segmentation allows different channel configurations to address various solid material types and sizes, improving adaptability while maintaining shedding effectiveness.
Solution Approach 2:
The channels are positioned and dimensioned to create specific local flow patterns and shear forces at critical locations where solid material accumulates. The land portions between channels provide localized resistance to prevent material from entering the impeller eye, while the channel geometry creates localized shedding zones that are effective for different solid types.
2Reliability
If a mechanical face seal is used to prevent liquid leakage, then sealing performance is improved, but the seal is damaged by foreign material wrapping and erosion
Solution Approach 1:
A seal shield is introduced as an intermediary component between the mechanical face seal and the harmful foreign material in the slurry. The seal shield is positioned to intercept and deflect solid particles and fibrous strands before they can reach and damage the seal, while allowing the seal to maintain its primary function of preventing liquid leakage. This protective intermediary element resolves the contradiction by protecting the seal without compromising its sealing capability.
3Productivity
If the pump is run without adequate liquid in the volute to maintain seal lubrication, then productivity is maintained, but the seal may be damaged by running dry
Solution Approach 1:
A liquid reservoir is provided in the volute that maintains a predetermined amount of liquid even during reduced flow conditions or temporary shutdowns. This reservoir acts as a cushion, ensuring that the seal remains lubricated and cooled by liquid before damage can occur. The reservoir compensates for liquid level drops and prevents the seal from running dry, allowing the pump to maintain productivity while protecting the seal from dry-running damage.
4Ease of manufacture
If multiple piece pump volute is used, then manufacturing flexibility is improved, but assembly cost and complexity increase
Solution Approach 1:
The pump volute is designed as a single integrated piece rather than multiple separate components. This merging of the volute into one unit eliminates the need for complex assembly operations, reducing assembly cost and complexity. The single-piece construction maintains manufacturing flexibility through various forming processes while avoiding the tolerance accumulation and alignment issues inherent in multi-piece assemblies.
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 enhances pump efficiency, extends seal life, reduces maintenance, and lowers manufacturing and energy costs by effectively shedding solids, protecting the seal, and optimizing the cutting process.
Implementation Method 1
a rotary impeller (100) and a volute (200) having features for causing solid material to be shed from the impeller (100). The impeller (100) is comprised of a flange (110) surrounding a central hub (120). The flange (110) includes a plurality of vanes (130), each vane (130) extending radially from the hub (120)...
Implementation Method 2
Typically a mechanical face seal is used that is comprised of two ground surfaces riding on each other with a very thin layer of liquid between them as a lubricant.
Implementation Method 3
A grinder pump is a pump that reduces the size of solid objects suspended in the liquid. In a typical grinder pump, a cutting or grinding device is incorporated into the suction opening of the pump, which chops or reduces the size of solid objects as the pump moves the liquid.
Data Source
AI summary
A pump for pumping liquids containing entrained solids. The pump is comprised of a volute surrounding an impeller comprising vanes that are self-cleaning. The outer surfaces of the vanes are coplanar and define a first plane and have a leading edge. The volute is comprised of a planar mating surface defining a second plane parallel to the first plane of the rotary impeller. The planar mating surface is proximate to the outer surfaces of the vanes and is comprised of a plurality of channels extending radially from the inner perimeter to the outer perimeter thereof. Each channel includes a forward edge in the direction of impeller rotation. The channels are oriented such that when the impeller is rotated within the volute, for any vane, the leading edge of the vane traverses each channel progressively from the inner end of the channel to the outer end of the channel.