Roll Mill Automatic Control via Laser and Load Sensors
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Solution Overview
Problem
Existing roll mills face challenges in achieving precise automatic control of the distance and pressure between rolls, leading to fluctuations in frictional force, unbalanced loads, and ineffective dispersion due to reliance on displacement control alone, which fails to account for viscosity changes and abnormal loads.
Innovation Solution
A roll mill with a combination of displacement and load control systems, utilizing a laser sensor for distance measurement and a load sensor for pressure feedback, where a servomotor adjusts the roll position to maintain a constant distance and pressure, and a program switches control from displacement to load control during disturbances to ensure continuous operation and prevent machine damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automatic control by servomotor is implemented instead of manual handle, then automation level is improved, but control precision deteriorates due to inability to correctly conduct automatic control with only load control by load sensor
Solution Approach 1:
The patent merges two control approaches: displacement control (using laser sensor to measure distance between rolls) and load control (using load sensor to measure pressing force). The controller integrates both control methods to simultaneously maintain accurate roll distance and pressing force, resolving the contradiction between automation and control precision.
Solution Approach 2:
The system implements feedback control by continuously measuring both displacement (via laser sensor) and load (via load sensor), comparing these measurements to target values, and adjusting the servomotor accordingly to maintain precise control of roll position and pressing force during automatic operation.
2Device complexity
If displacement control alone is used, then device complexity is reduced, but reliability deteriorates due to failure to account for viscosity changes and abnormal loads
Solution Approach 1:
The patent implements load feedback control by installing a load sensor to detect the pressing force between rolls. The controller uses this feedback to adjust the servomotor and maintain constant pressing force, ensuring reliable operation even when material viscosity changes or abnormal loads occur, without significantly increasing system complexity.
3Measurement precision
If load sensor is used for load control, then measurement precision is improved, but device complexity increases due to need for combination of sensors and control programs
Solution Approach 1:
The patent combines displacement measurement (laser sensor) and load measurement (load sensor) into a unified control system. The controller integrates both measurement signals to simultaneously control roll position and pressing force, achieving high measurement precision while managing system complexity through coordinated control of multiple parameters.
4Device complexity
If manual handle is used for roll adjustment, then device complexity is reduced, but productivity deteriorates due to inability to maintain constant distance and pressure during operation
Solution Approach 1:
The patent implements automatic self-adjustment of roll position and pressing force through the controller that continuously monitors displacement and load measurements. The system automatically maintains constant distance and pressure between rolls during operation, eliminating the need for manual adjustment while ensuring consistent dispersion quality, thereby improving productivity without excessive 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 solution enables continuous operation with constant contact force, maintaining dispersion quality and preventing machine damage by accounting for roll self-alignment, viscosity changes, and abnormal loads, resulting in improved particle size distribution and reduced human intervention.
Implementation Method 1
a laser sensor being disposed between the fixed roll and the transfer roll for measuring the distance between the rolls
Implementation Method 2
a load sensor for measuring a pressing force between the rolls
Implementation Method 3
the transfer roll being slightly movable in a direction perpendicular to the fixed roll by a servomotor and a ball screw
Implementation Method 4
the pressing side roll and the fixed side roll are rotated at different speeds (i.e., the numbers of revolutions of the rolls are different from each other) so that a frictional force is generated between the rolls
Data Source
AI summary
A roll mill for a milling-dispersing treatment has a fixed roll fixed to a frame, and a transfer roll displaceable into and out of contact with the fixed roll in a direction perpendicular to the fixed roll by a servomotor and a ball screw. A laser sensor disposed between the fixed roll and the transfer roll measures the distance between the rolls, and a load sensor measures a pressing force between the rolls. An electronic automatic control device maintains a constant distance and a constant pressing force between the fixed roll and the transfer roll by feedback of detection signals sent from the respective sensors, wherein the servomotor is driven by the electronic automatic control device to adjust the position of the transfer roll.