Nip Force Control Using Stationary Pressure Sensor
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Solution Overview
Problem
Existing methods for measuring and controlling nip forces between rotating rolls in paper manufacturing processes are complex, prone to disturbances, and require cumbersome calibration, especially when dealing with rubberized or elastomeric roll covers, which can lead to thermal issues and inconsistent product quality.
Innovation Solution
An apparatus comprising a fixed roll, a pivoting roll, a load cylinder, and an adjustable stop with a pressure sensing device and controller, allowing for precise measurement and adjustment of nip forces by adjusting the position of the adjustable stop relative to the rolls, enabling on-line measurement and easier calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional signal transfer devices (glide rings, telemetry equipment) are used to transfer signals from rotating rolls, then signal transfer is achieved, but the devices become complicated and susceptible to disturbance
Solution Approach 1:
The patent extracts the signal transfer function from the rotating roll system by using a stationary pressure sensing device that measures nip force directly at the nip point. This eliminates the need for complex signal transfer devices like glide rings and telemetry equipment that were required to transmit signals from rotating components, thereby simplifying the overall system while maintaining reliable measurement capability.
2Productivity
If pressure sensing devices are placed on rotating rolls for on-line measurement, then continuous monitoring is achieved, but the devices become susceptible to thermal changes and require frequent calibration
Solution Approach 1:
The patent introduces a stationary pressure sensing device as an intermediary that measures the nip force at the contact point between rolls without being attached to the rotating rolls themselves. This mediator approach allows continuous on-line measurement while avoiding the thermal issues and calibration problems that arise when sensors are mounted directly on rotating, heat-generating roll surfaces.
3Measurement precision
If manual calibration and adjustment of nip force measurement systems is performed, then measurement accuracy can be maintained, but equipment downtime increases
Solution Approach 1:
The stationary pressure sensing device provides continuous, automatic measurement of nip force without requiring manual calibration or adjustment. The system self-maintains measurement capability by continuously monitoring the actual nip force at the roll contact point, eliminating the need for periodic shutdowns and manual calibration procedures that cause equipment downtime.
4Manufacturing precision
If rubberized or elastomeric roll covers are used, then desirable product characteristics are achieved, but thermal issues arise leading to inconsistent quality
Solution Approach 1:
The stationary pressure sensing device provides real-time feedback on the actual nip force being applied between rolls. This feedback mechanism allows the control system to detect and compensate for variations caused by thermal changes in rubberized or elastomeric roll covers, maintaining consistent product quality despite temperature fluctuations that would otherwise lead to inconsistent measurements and product characteristics.
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 provides accurate and efficient monitoring and control of nip forces, reducing downtime due to thermal changes and enabling rapid product changes, resulting in more uniform product characteristics and reduced operational costs by minimizing the need for manual adjustments and equipment downtime.
Implementation Method 1
The pressure sensing device is capable of measuring a pressure exerted by the pivoting roll upon the adjustable stop
Data Source
AI summary
An apparatus for controlling the nip force between a fixed roll having a first longitudinal axis and a pivoting roll pivotable about a pivot axis and having a second longitudinal axis is disclosed.