Variable-Speed Bottom Ash Crusher Feed Control for Low-Capacity Conveyors
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Solution Overview
Problem
Existing bottom ash handling systems face challenges in achieving a high turndown ratio due to varying capacities among subsystems, leading to bottlenecks and arching issues, particularly with the use of low capacity conveyors in continuous operations.
Innovation Solution
A system incorporating a variable speed side discharge crusher with an offset conduit and diluting spray pipe, along with a controller that adjusts flow rates based on conveyor signals, effectively turning the crusher into a pumping device to manage ash flow without relying on a bottom gate, and optional orifice plates or extended wear plates to further control the flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bottom gate is used to control ash flow from the hopper, then flow control is achieved, but arching occurs and requires frequent adjustments
Solution Approach 1:
The patent removes the bottom gate control mechanism entirely and replaces it with a variable speed crusher that controls ash flow through its rotational speed. This extraction of the problematic gate mechanism eliminates arching while maintaining flow control capability.
Solution Approach 2:
The patent replaces the mechanical bottom gate system with a variable speed crusher system. The crusher's rotational speed is adjusted to control ash flow rate, substituting the gate's mechanical flow control with a different mechanical approach that avoids arching.
2Adaptability or versatility
If the bottom gate is partially closed to control flow, then flow modulation is achieved, but larger particles block the gate increasing arching risk
Solution Approach 1:
The patent eliminates the bottom gate that is prone to particle blocking by using a variable speed crusher to control flow. The crusher can adjust its rotational speed to match different ash flow conditions without creating the blocking problem associated with partial gate closure.
Solution Approach 2:
The patent employs a variable speed crusher that can dynamically adjust its rotational speed to control ash flow rate. This dynamic adjustment capability allows the system to adapt to varying ash conditions without the static gate mechanism that causes blocking and arching.
3Productivity
If a low capacity conveyor is used in continuous operations, then processing efficiency is improved, but flow control becomes difficult and bottlenecks occur
Solution Approach 1:
The patent implements a feedback control system where the variable speed crusher adjusts its rotational speed based on conveyor load conditions. This feedback mechanism allows the system to maintain optimal flow control despite the low capacity conveyor's limitations in continuous operation.
Solution Approach 2:
The variable speed crusher provides dynamic flow control that can adapt to the low capacity conveyor's requirements during continuous operation. By continuously adjusting the crusher's rotational speed, the system maintains appropriate feed rates without creating bottlenecks or requiring frequent interventions.
4Reliability
If the bottom gate is opened to clear arching, then flow is restored, but overfeeding occurs leading to further arching
Solution Approach 1:
The patent removes the bottom gate mechanism that causes the cycle of arching and overfeeding by using a variable speed crusher to control flow. The crusher can gradually adjust flow rates without creating the sudden overfeeding that occurs when gates are opened to clear arching.
Solution Approach 2:
The variable speed crusher can implement periodic or cyclic control of ash flow, gradually adjusting rotational speed to prevent sudden changes in flow rate. This periodic adjustment prevents the overfeeding condition that results from sudden gate opening to clear arching.
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
Enables continuous operation with improved turndown ratio, reduces arching, and minimizes wear on conveyor components by optimizing flow control through the crusher, ensuring efficient and uninterrupted ash processing.
Implementation Method 1
diluting spray pipe
Implementation Method 2
variable speed side discharge crusher
Implementation Method 3
hopper for collecting the ash, a crusher for grinding the ash
Data Source
AI summary
A system and mechanism for bottom ash flow turndown from a hopper, through a crusher, and to a conveyor, the system including a fixed flow restrictor and a variable speed side discharge crusher to modulate bottom ash flow in the absence of gate or valve flow from a hopper, the conveyor providing a signal corresponding to an overfeed condition to enable a controller to operate the crusher and/or the conveyor to eliminate overfeed conditions.