Pull Roll Apparatus for Glass Sheet Tension Control
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Solution Overview
Problem
Traditional pull roll apparatuses in glass manufacturing struggle to control cross-draw tension and down-draw tension consistently, leading to residual stress and inconsistent flatness in glass sheets, due to instantaneous force variability and variable ribbon load effects.
Innovation Solution
A pull roll apparatus featuring a first and second stub roll pair, controlled by a programmable logic controller, which can adjust the tilt angle and torque of rolls to manage cross-draw and down-draw tensions, using either vertically downtilted or horizontally level rolls, to maintain consistent tension and reduce residual stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional pull roll apparatus is used to draw glass sheet, then glass sheet can be manufactured, but cross-draw tension and down-draw tension cannot be controlled consistently, leading to residual stress and inconsistent flatness
Solution Approach 1:
The pull roll apparatus is divided into multiple independent roll pairs (first and second stub roll pairs) that can be controlled separately. Each roll pair handles specific portions of the glass sheet edges, allowing independent adjustment of cross-draw and down-draw tensions to achieve consistent control and reduce residual stress
Solution Approach 2:
The invention employs dynamically adjustable roll configurations where the tilt angle and torque of each roll can be modified during operation. The programmable logic controller enables real-time adjustments to maintain optimal tension control, transforming static rolls into dynamic, adaptive components that respond to varying glass sheet conditions
2Reliability
If traditional pull roll apparatus with fixed rolls is used, then apparatus structure is simple, but instantaneous force variability and variable ribbon load effects cannot be compensated
Solution Approach 1:
The programmable logic controller implements feedback control by monitoring the positions and torques of the stub roll pairs and automatically adjusting them to maintain consistent tension. This closed-loop control system compensates for instantaneous force variability and variable ribbon load effects, ensuring stable tension control despite increased system complexity
Solution Approach 2:
The invention changes multiple parameters simultaneously including roll tilt angles, roll torques, and roll positions to optimize tension control. By dynamically adjusting these parameters through the control system, the apparatus compensates for load variations and maintains reliable tension control throughout the glass sheet drawing process
Data Source
AI summary
A pull roll apparatus and method are described herein that can control a cross-draw tension and a down-draw tension of a glass sheet while manufacturing the glass sheet. In one embodiment, the pull roll apparatus includes a first driven stub roll pair, a second driven stub roll pair and a control device (e.g., PLC) that controls the first and second driven stub roll pairs while a first edge portion of the glass sheet is drawn between two vertically downtilted rolls associated with the first driven stub roll pair and while an opposing second edge portion of the glass sheet is drawn between two vertically downtilted rolls associated with the second driven stub roll pair. If desired, the pull roll apparatus may include a pulling roll assembly (located below the first and second driven stub rolls) or another set of driven stub roll pairs (located below the first and second driven stub roll pairs).