Wood Chipper Feed Control for Production Rate
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Solution Overview
Problem
Conventional drum-type wood chippers operate at a lower production rate when maintaining uniform chip size due to resistance-induced slowdowns, requiring operators to stop and restart the feed mechanism, leading to inefficiencies in chipping mode, or produce non-uniform chips in grinding mode to avoid stalling.
Innovation Solution
A controller system that adjusts the feed rate of wood to the chipper drum in real-time based on engine operating rate changes, allowing for a higher production rate while maintaining chip size uniformity by determining specific decline rates for feed system speed as engine speed decreases, between chipping and grinding modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the feed mechanism operates continuously at high speed to maximize production rate, then productivity increases, but chip size uniformity deteriorates due to resistance-induced drum slowdowns
Solution Approach 1:
The patent applies dynamics by making the feed mechanism speed variable rather than fixed. The controller dynamically adjusts the feed mechanism speed based on real-time monitoring of chipper drum rotational speed, allowing the system to adapt to changing resistance conditions while maintaining optimal chip size uniformity and maximizing production rate.
Solution Approach 2:
The patent implements feedback control by using sensors to monitor the chipper drum rotational speed and using this information to adjust the feed mechanism speed. The controller receives feedback about drum speed changes and automatically modifies feed rate to compensate for resistance-induced slowdowns, maintaining chip size uniformity without stopping production.
2Manufacturing precision
If the feed mechanism speed is reduced to maintain chip size uniformity during drum slowdowns, then chip size uniformity is maintained, but productivity decreases due to frequent stoppages
Solution Approach 1:
The patent applies continuity of useful action by eliminating the need to stop the feed mechanism. The controller continuously adjusts the feed mechanism speed to match drum speed variations, ensuring that the feed mechanism operates without interruption while maintaining chip size uniformity, thus maximizing productivity.
Solution Approach 2:
The system dynamically adjusts feed mechanism speed in real-time based on drum speed feedback, allowing continuous operation rather than intermittent stopping. This dynamic adjustment maintains chip size uniformity while keeping the production process continuous and efficient.
3Reliability
If the feed mechanism speed is reduced rapidly to prevent engine stalling, then engine reliability is maintained, but chip size uniformity deteriorates due to excessive feed rate reduction
Solution Approach 1:
The patent uses feedback control to monitor drum speed and adjust feed mechanism speed proportionally. The controller receives continuous feedback about drum speed changes and makes corresponding adjustments to feed rate, preventing both engine stalling and excessive feed rate reduction that would compromise chip size uniformity.
Solution Approach 2:
The system changes the feed mechanism speed parameter in response to drum speed changes, but controls the rate and magnitude of this change to maintain both engine reliability and chip size uniformity. The controller adjusts parameters dynamically within optimal ranges to balance these competing requirements.
Data Source
AI summary
A drum-type wood chipper for processing wood includes a chipper drum that is adapted to rotate about a generally horizontal drum axis, a plurality of cutting blades that are disposed around the periphery of the chipper drum, and an engine that is adapted to rotate the chipper drum about the drum axis. The wood chipper also includes a feed system that is adapted to advance wood to be processed towards the chipper drum, and a controller that is operatively connected to the engine and adapted to determine an instantaneous engine operating rate during rotation of the chipper drum. The controller is also operatively connected to the feed system and adapted to control the rate of advance of wood towards the chipper drum. The controller is also adapted to modify the rate of advance of wood towards the chipper drum as the instantaneous engine operating rate changes while the chipper drum is being rotated.