Transfer Chute Design Using Stall Angle for Wear Reduction
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Solution Overview
Problem
Transfer chutes in bulk materials handling operations face challenges with complex ores due to issues like material size variations, moisture content, abrasive nature, and cohesive/adhesive properties, leading to maintenance burdens and production constraints, as existing designs struggle to accurately model and manage dense granular flow effectively.
Innovation Solution
The design of transfer chutes is optimized by utilizing the concept of the stall angle, which is the angle at which material sets in the dense granular flow regime, to control effective friction and flow patterns, incorporating lower wall angles and ledges to create a controlled accumulation and build-up of material, ensuring efficient flow and reduced wear, with the stall angle typically set at 63 degrees for cohesive ores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional transfer chute designs are used, then material flow capacity is maintained, but wear increases and maintenance frequency increases
Solution Approach 1:
The patent changes the geometric parameters of the transfer chute by introducing ledges at specific intervals and optimizing wall angles to match the stall angle of the material (typically 63 degrees for cohesive ores). This parameter optimization creates controlled accumulation zones that reduce direct material-to-chute contact and wear, extending maintenance intervals while preserving flow capacity
Solution Approach 2:
The transfer chute is segmented into multiple sections with ledges positioned at specific intervals along the flow path. These ledges create discrete accumulation zones that break up continuous material flow, reducing impact forces and wear on the chute surfaces while maintaining overall material throughput
2Quantity of substance
If wall angles are reduced to control flow, then material accumulation is improved, but flow turbulence may increase
Solution Approach 1:
The patent optimizes wall angles to match the stall angle of the material (typically 63 degrees for cohesive ores), creating a balanced flow regime. This parameter selection allows controlled material accumulation against the walls while preventing excessive turbulence or uncontrolled buildup, maintaining flow stability
Solution Approach 2:
Different sections of the transfer chute have different wall angles optimized for local conditions. The ledges are positioned at specific locations where accumulation is desired, while other sections maintain smoother walls to prevent turbulence. This localized optimization balances accumulation needs with flow stability
3Object-affected harmful factors
If ledges are added to create accumulation zones, then wear is reduced, but device complexity increases
Solution Approach 1:
The transfer chute is segmented into multiple sections with ledges positioned at specific intervals along the flow path. These ledges create discrete accumulation zones that reduce direct material-to-chute contact and wear, extending maintenance intervals while preserving flow capacity
Solution Approach 2:
The patent changes the geometric parameters of the transfer chute by introducing ledges at specific intervals and optimizing wall angles to match the stall angle of the material (typically 63 degrees for cohesive ores). This parameter optimization creates controlled accumulation zones that reduce direct material-to-chute contact and wear, extending maintenance intervals while preserving flow capacity
4Productivity
If material flow is accelerated to maintain capacity, then productivity increases, but wear increases
Solution Approach 1:
The patent optimizes the geometric parameters of the transfer chute including wall angles set to match the stall angle of the material and ledges positioned at specific intervals. These parameter changes create controlled accumulation zones that allow material to flow at high speeds without direct impact on chute surfaces, maintaining productivity while reducing wear
Solution Approach 2:
The ledges and accumulated material act as intermediaries between the high-speed material flow and the chute surfaces. Instead of material directly impacting the chute walls, the accumulated material layers and ledge structures absorb and dissipate impact forces, protecting the chute from wear while allowing continued high-capacity throughput
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 approach results in a transfer chute that maintains system capacity, reduces wear, and improves material presentation to receiving belts, minimizing maintenance and production downtime by managing complex ore flows effectively through controlled accumulation and flow patterns.
Implementation Method 1
The design of transfer chutes is optimized by utilizing the concept of the stall angle, which is the angle at which material sets in the dense granular flow regime, to control effective friction and flow patterns
Implementation Method 2
the pathway being so designed to create a controlled accumulation and build-up of material, whereby material flowing along the pathway can impinge upon the accumulated material
Data Source
AI summary
A transfer chute (10) for use in bulk materials handling operations, and also a methodology for designing such a transfer chute, a method of constructing the transfer chute, and a method of transferring bulk materials between two locations using the transfer chute. The transfer chute (10) comprises a chute body (11) defining a flow pathway (19), with an upper section (19a) of the flow pathway accommodating accelerating flow to maintain dense granular flow regime, an intermediate section (19b) of the flow pathway providing consolidated flow in which the flow rate is retarded in a controlled manner avoiding creation of flow turbulence, and a lower section (19c) of the flow pathway in which flow is further retarded to create a controlled accumulation and build-up of material upwardly from the lower section.