Tension Half-Ring Sensor for Nip Roll Deformation
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Solution Overview
Problem
Existing technologies struggle to reliably measure and characterize the deformation of nip rolls in paper and board machines, which leads to vibration and fluctuation in nip force, affecting the quality of the end-product.
Innovation Solution
A sensor device comprising a tension half-ring with strain gages in a Wheatstone bridge configuration is attached to the supporting frames of the rolls, measuring deformation by detecting variations in the axial distance between them without directly measuring the distance, using a weakly bent beam type tension half-ring equipped with strain gages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gages are attached directly to the roll surface to measure deformation, then measurement precision is improved, but the complexity of the device and difficulty of installation increase
Solution Approach 1:
The patent introduces a tension half-ring as an intermediary element attached to the supporting frames of the rolls. This half-ring deforms in response to changes in the axial distance between the rolls, and strain gages attached to the half-ring measure this deformation. The intermediary converts the difficult-to-measure roll surface deformation into an easily measurable tension ring deformation, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If complex measurement systems are used to accurately characterize roll deformation, then measurement precision is improved, but the cost and ease of manufacture worsen
Solution Approach 1:
The patent employs a simple tension half-ring structure with strain gages that can be manufactured at low cost using standard components. The half-ring itself can be made from inexpensive materials, and the strain gages are commercial off-the-shelf items. This approach achieves accurate deformation measurement without requiring expensive specialized equipment, resolving the contradiction between measurement precision and ease of manufacture.
3Measurement precision
If direct distance measurement between rolls is implemented, then measurement precision is improved, but the device complexity and disruption to machine operation increase
Solution Approach 1:
The patent attaches the tension half-ring to the supporting frames of the rolls in advance, so that the measurement system is already in place and operational when the rolls begin to deform. The half-ring continuously tracks the axial distance changes without requiring active measurement actions or interruptions to the rolling process, resolving the contradiction between measurement precision and ease of operation.
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
Provides accurate and reliable measurement of nip roll deformations, determining periodicity and magnitude of deformations causing unwanted oscillations, without disrupting the operation of the machine and at a lower cost.
Implementation Method 1
four strain gages attached pairwise on outer and inner surfaces of the tension half-ring and coupled into a Wheatstone bridge configuration
Implementation Method 2
four strain gages attached pairwise on outer and inner surfaces of the tension half-ring and coupled into a Wheatstone bridge configuration
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3C
AI summary
The present invention relates to sensor device for detecting deformation of a surface of at least one of two rolls which form a nip between said two rolls, as well as on a method of detecting such deformation. The sensor device comprises a frame part comprising a tension half-ring attached at its ends between two straight portions, and four strain gages attached pairwise on outer and inner surfaces of the tension half-ring and coupled into a full bridge configuration. The sensor device is configured to be attached to supporting frames of the two rolls such that the longitudinal central axis of the frame part is parallel with a straight line traveling via central rotation axes of the two rolls and the nip therebetween.