Offset Magnetic Field Orientation Sensors for Scanner Head Gap Measurement
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Solution Overview
Problem
In paper machines and similar systems, accurately measuring the Z gap distance between scanner heads is challenging due to interference from opaque web materials, limiting the use of optical sensors and requiring expensive inductive coil technologies.
Innovation Solution
A magnetic field orientation sensor system is used, with at least one sensor offset from the centerline to measure both displacement and gap separation, allowing for accurate Z gap measurements without relying on costly inductive coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are used for measuring Z gap distance, then measurement precision is improved, but the system becomes sensitive to interference from opaque web materials
Solution Approach 1:
The patent introduces magnetic field orientation sensors as an intermediary measurement mechanism that indirectly measures Z gap distance through magnetic field orientation changes rather than direct optical measurement. This mediator approach allows measurement through opaque materials by using magnetic fields that are not blocked by the web material.
Solution Approach 2:
The patent replaces the optical sensing system with a magnetic sensing system. Instead of using light-based optical sensors that are blocked by opaque materials, the system uses magnetic field orientation sensors that generate and detect magnetic fields, which can penetrate opaque web materials to measure gap distances.
2Measurement precision
If inductive coil technologies are used for absolute Z gap measurement, then measurement precision is improved, but device cost increases significantly
Solution Approach 1:
The patent replaces expensive inductive coil technologies with cheaper magnetic field orientation sensors. The magnetic field orientation sensors provide the necessary measurement capability at a lower cost, making the system more economically viable while maintaining measurement precision through clever use of sensor positioning and magnetic field characteristics.
Solution Approach 2:
The patent changes the measurement parameter from direct inductive coupling to magnetic field orientation detection. By measuring the orientation of magnetic field lines rather than using inductive coils, the system achieves absolute Z gap measurement capability with lower-cost sensors. The offset positioning of sensors creates a measurable relationship between magnetic field orientation and gap distance.
3Measurement precision
If magnetic field orientation sensors are placed on the centerline, then displacement sensing in X and Y directions is accurate, but Z gap measurement capability is lost
Solution Approach 1:
The patent deliberately positions magnetic field orientation sensors at an offset from the centerline, creating an asymmetric configuration. This asymmetric positioning is key to the invention because it creates a magnetic field geometry where the orientation of field lines becomes sensitive to both Z gap distance and X-Y displacement, allowing simultaneous measurement of both parameters with a single sensor type.
Solution Approach 2:
The patent makes the magnetic field orientation sensor multi-functional by positioning it off-center. The same sensor that measures displacement in X and Y directions also provides Z gap measurement capability through its sensitivity to magnetic field orientation changes. This universal sensor approach eliminates the need for separate sensors for different measurement functions.
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 approach maintains constant alignment of scanner heads, reduces costs, and provides accurate displacement sensing in the Z direction, while being insensitive to variations in the X and Y directions within a defined displacement range.
Implementation Method 1
a magnet that generates a magnetic field that extends through space
Implementation Method 2
multiple magnetic field orientation sensors that measure the orientation of magnetic flux lines produced by the magnet
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
A gap and displacement magnetic sensor system for scanner heads in paper machines or other systems includes a multiple-sensor assembly (414b). The multiple-sensor assembly includes multiple magnetic field orientation sensors (514x-514z) configured to capture measurements of a magnetic field (550 552) in order to identify (i) a displacement of first and second scanning sensor heads in a first direction (X-Direction), and (ii) a gap separation of the first (410a) and second scanning sensor heads (410b) in a second direction (Z-Direction), and (iii) a displacement of the first and second scanning sensor heads in a third direction (Y- Direction). At least one of the magnetic field orientation sensors (514z) is disposed offset from a centerline (552) of the magnetic field such that an output from the at least one magnetic field orientation sensor indicates a combination of the gap separation and the displacement in either the first direction or the third direction.