Curved Pellet Chute for Ore Delivery Speed Control
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Solution Overview
Problem
The existing screening and delivering apparatus for green ore pellets to induration furnaces often results in deagglomeration, leading to inefficient energy use due to random packing and poor heat exchange, as undersize pellets mix with larger ones on the travelling grate, requiring excessive energy to achieve suitable firing.
Innovation Solution
A screening apparatus with a delivery screening deck and curved pellet chutes that reduce the delivery speed of green ore pellets, featuring an input slope greater than the output slope to minimize deagglomeration, and multiple superposed screening decks to segregate pellets by size, ensuring optimal energy distribution based on physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If green ore pellets are delivered quickly onto the travelling grate, then productivity is improved, but deagglomeration occurs causing pellets to break into smaller sizes
Solution Approach 1:
The pellet chute is designed with a curved delivery path instead of a straight path. The curve radius is specifically selected to reduce the delivery speed of green pellets while maintaining high productivity. This curvature allows pellets to follow a gentler trajectory, reducing impact forces and preventing deagglomeration during delivery to the travelling grate.
2Device complexity
If deagglomerated balls are delivered onto the travelling grate, then device complexity is reduced, but energy consumption increases due to random packing
Solution Approach 1:
The system performs preliminary sizing action by screening green pellets before delivery to the travelling grate. Multiple screening decks with different aperture sizes separate pellets into appropriate size ranges (e.g., 8-10mm, 10-12mm, 12-14mm) before induration. This preliminary classification ensures that only properly sized pellets are delivered, preventing deagglomeration and enabling optimal bed packing that reduces firing energy requirements.
3Manufacturing precision
If large and small pellets are mixed in the pellet bed, then manufacturing precision is simplified, but heat exchange efficiency deteriorates
Solution Approach 1:
The screening system is divided into multiple decks (typically 2-4 decks) with progressively different aperture sizes. Each deck segment handles a specific size range, creating segregated size zones in the final pellet bed. This segmentation allows large pellets to be positioned in regions requiring more energy and small pellets in regions requiring less energy, optimizing heat exchange efficiency during induration.
4Productivity
If the pellet chute has a steep slope, then delivery speed increases improving productivity, but deagglomeration increases reducing pellet quality
Solution Approach 1:
The pellet chute incorporates a curved delivery path with an optimized radius that balances delivery speed and pellet integrity. The curve allows pellets to accelerate under gravity while following a smooth trajectory, maintaining productivity without the excessive steep slopes that cause deagglomeration. The curvature acts as a speed-regulating mechanism that preserves pellet quality.
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 reduces deagglomeration, enhances pellet bed permeability, and improves energy efficiency by segregating pellets by size, allowing for more effective heat exchange and reduced energy consumption during the induration process.
Implementation Method 1
the pellet chute defining a curve along a pellet flow direction with an input slope defined at the chute pellet input of the curved delivery path that is greater than an output slope of the chute pellet output of the curved delivery path to reduce a delivery speed of the green ore pellets
Data Source
AI summary
A screening apparatus comprises superposed screening decks with an upper one of the screening decks having a pellet input, and each screening deck ends with an oversize pellet output, the screening decks have screens to screen the green ore pellets from top to bottom, the oversize pellet outputs feeding the travelling grate through pellet chutes with the oversize green ore pellets of one of the upper and the lower one of the screening decks being superposed to oversize green ore pellets of the other one of the lower and the upper one of the screening decks, the pellet chutes defining a curved delivery path with an input slope at the chute pellet input greater than an output slope of the chute pellet output to reduce a delivery speed of the green ore pellets from the oversize pellet output to the travelling grate. There is also provided a method for screening and delivering green ore pellets onto a travelling grate of an induration furnace.