Rope Winch Control for Waste Paper Pulping
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Solution Overview
Problem
The variability in composition and diameter of the plait formed during the processing of waste paper in pulpers often leads to jamming issues in ragger systems, causing disruptions and potential standstills, which can result in further thickening and subsequent faults if not addressed promptly.
Innovation Solution
The contact pressure of the rollers in the ragger winch is controlled based on the movement speed and direction of the plait, with the pressing force reduced when deviations occur, and increased back to normal once the issue is resolved, allowing for continuous or intermittent conveyance and minimizing the risk of jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact pressure of the rollers is increased to prevent the plait from slipping back into the pulper, then the plait is securely conveyed, but the risk of jamming increases when the plait thickens
Solution Approach 1:
The contact pressure of the rollers is made dynamically adjustable rather than fixed. The control unit modifies the contact pressure in real-time based on feedback from the sensor about plait movement speed and direction, allowing the system to adapt to varying plait conditions (normal operation vs. thickening/jamming risk) and resolve the contradiction between preventing slip-back and avoiding jamming
Solution Approach 2:
A sensor detects the movement speed and direction of the plait and provides feedback to the control unit. Based on this feedback, the control unit adjusts the contact pressure accordingly - increasing it when the plait slows or reverses (preventing slip-back) and maintaining or reducing it when normal speed is achieved (preventing jamming), thus dynamically resolving the contradiction
2Productivity
If the pressing force is reduced to allow thickened plait to pass through the press gap, then jamming is avoided, but the plait may slip back into the pulper
Solution Approach 1:
The contact pressure is dynamically adjusted based on real-time plait movement conditions. When thickening is detected (speed deviation), pressure is reduced to allow passage; when plait movement normalizes or reverses, pressure is increased to prevent slip-back, ensuring both productivity and reliability are maintained through adaptive control
Solution Approach 2:
The sensor continuously monitors plait movement and provides feedback to the control unit, which adjusts pressing force accordingly. This closed-loop control ensures that pressure reduction to facilitate thickened plait passage is temporary and automatically reversed when appropriate, preventing both jamming and slip-back
3Measurement precision
If complex methods are used to detect the composition and shape of the braid for control purposes, then accurate detection is achieved, but the system complexity increases
Solution Approach 1:
The invention extracts only the essential control parameter (plait movement speed and direction) from the complex set of possible detection parameters (composition, shape, diameter, etc.). By using a simple sensor to monitor roller rotation and infer plait movement, the system achieves sufficient detection accuracy without the complexity of analyzing multiple braid characteristics
Solution Approach 2:
The invention replaces complex mechanical or optical detection systems that would directly analyze braid composition and shape with a simple rotational sensor that indirectly detects plait conditions through roller rotation speed. This substitution maintains measurement precision for control purposes while dramatically reducing system complexity
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 effectively reduces the likelihood and duration of disruptions, simplifies fault detection and resolution, and ensures smooth operation by adjusting the contact pressure in response to speed deviations, thereby preventing thickening and slipping issues.
Implementation Method 1
the contact pressure of the rollers is controlled as a function of the movement of the braid
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling a rope winch (3) which conveys a rope (1) which is formed from contaminants out of a pulper (2) for defibring fibrous materials which are loaded with contaminants, and is formed by at least two rollers (6, 7) which are pressed against one another and through the pressure nip of which the rope (1) runs. Here, disruptions are to be reduced by the fact that the pressing force of the rollers (6, 7) is controlled in a manner which depends on the movement of the rope (1).