Refiner Beating Gap Sensor With Wear-Protected Calibration Head
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Solution Overview
Problem
Current sensor devices for measuring the beating gap between refining discs in paper pulp production are prone to precision issues due to wear and tear of the measuring head, leading to inaccurate measurements and potential misalignment during calibration.
Innovation Solution
A sensor device with a non-magnetic measuring head that abuts the refining disc during calibration, coupled with a magnetic pole and coil assembly, allows for precise gap measurement by generating a magnetic field and converting it into electrical signals, while maintaining the magnetic pole's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the measuring head is made of magnetic material to enable calibration contact with the refining disc, then calibration can be performed, but the magnetic pole is subject to wear and tear leading to reduced measurement precision
Solution Approach 1:
The measuring head is segmented into two distinct parts: a non-magnetic outer end for calibration contact and a magnetic inner part for field generation. This segmentation allows each part to perform its specific function without suffering from the drawbacks of the other material type.
Solution Approach 2:
A non-magnetic outer end acts as an intermediary element between the magnetic pole and the refining disc during calibration. This intermediary protects the magnetic pole from direct contact and wear while still enabling the calibration process to occur.
2Manufacturing precision
If the measuring head contacts the refining disc during calibration, then calibration position can be established, but wear occurs on the measuring head components
Solution Approach 1:
The non-magnetic outer end is designed as a consumable component that can wear during calibration without affecting the permanent magnetic pole. This allows the calibration function to be performed repeatedly while protecting the critical magnetic field-generating components from wear.
Solution Approach 2:
The non-magnetic outer end serves as a sacrificial intermediary that absorbs the wear during calibration contact, protecting the magnetic pole from material loss while enabling accurate calibration positioning.
3Ease of operation
If the measuring head is made of magnetic material for calibration, then it can be brought into contact with the refining disc, but it may cause misalignment due to abutment at wrong positions
Solution Approach 1:
The measuring head has different material properties at different locations: the outer end is non-magnetic for calibration contact while the inner part is magnetic for field generation. This local differentiation ensures that calibration contact occurs at the correct position without interference from magnetic attraction at wrong locations.
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
Ensures accurate and cost-effective calibration by preventing wear on the magnetic pole, ensuring reliable gap measurement and efficient operation of the refiner apparatus.
Implementation Method 1
a coil assembly arranged around the magnetic pole
Implementation Method 2
transducers of magnetic type, preferably working according to the reluctance principle
Data Source
AI summary
The present invention concerns a sensor device (1) comprising a transducer (3) adapted to generate a magnetic field (MF), the sensor device (1) is configured to measure a beating gap (G) between a first (5) and a second (7) refining disc of a refiner apparatus (9) and is configured to be mounted in the first refining disc (5), the sensor device (1) comprises a magnetic pole (13), a coil assembly (15) and a measuring head (11′), which measuring head (11′) is configured to be set in calibration position relative to the second refining disc (7) for calibration of the sensor device (1). The measuring head (11′) comprises an outer end (10′) made of a non-magnetic material configured to be positioned in abutment with the second refining disc (7) in a calibration sequence. The present invention also concerns a method of calibration of said sensor device (1).