Valve Position Sensing With Multi-Sensor Magnetic Calibration
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Solution Overview
Problem
Existing position sensors for valve members in fluid flow control devices face accuracy issues due to magnetic field degradation over time and temperature changes, especially in remote locations like subterranean or subsea settings, requiring frequent recalibration which is costly and impractical.
Innovation Solution
A fluid flow control device with a magnet mounted on the valve member and multiple magnetic field sensors on the housing, allowing for accurate position determination through changes in the magnetic field strength and angle, with automatic calibration capabilities for field degradation, using a plurality of sensors to enhance measurement accuracy and reduce the need for recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single magnetic field sensor is used to determine valve member position, then the device complexity is reduced, but the measurement precision deteriorates due to magnetic field degradation over time and temperature changes
Solution Approach 1:
The single magnetic field sensor is segmented into multiple sensors (at least two) positioned at different locations relative to the magnet. This segmentation allows the system to measure magnetic field strength from multiple perspectives, enabling more accurate position determination even when the magnet's field strength degrades over time or with temperature changes. The multiple measurements can be processed to compensate for field degradation without requiring recalibration.
2Measurement precision
If regular recalibration of the magnetic field sensor is performed, then the measurement precision is maintained, but the loss of time and operational disruption increase
Solution Approach 1:
The system performs preliminary calibration during the manufacturing process, establishing the relationship between magnetic field strength and valve member position before the magnet undergoes significant degradation. This preliminary calibration data is stored and used as a reference throughout the valve's operational life, eliminating the need for frequent recalibration and avoiding operational disruption.
Solution Approach 2:
The multiple magnetic field sensors provide continuous feedback about the magnetic field strength at different positions. By analyzing the pattern of magnetic field measurements from multiple sensors, the system can detect and compensate for gradual magnet degradation in real-time, maintaining measurement precision without requiring external recalibration interventions.
3Measurement precision
If a magnet with strong magnetic field is used, then the measurement precision is improved, but the sensitivity to temperature changes and field degradation increases
Solution Approach 1:
Instead of relying on a single strong magnet that is highly sensitive to degradation, the system segments the measurement function across multiple magnetic field sensors. This allows the use of a magnet with moderate field strength while achieving high measurement precision through multiple measurements. The segmented approach reduces the impact of temperature changes and field degradation on overall system reliability.
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
The solution provides a more accurate and economical means to determine the position of the valve member, maintaining precision over time and temperature changes without the need for frequent recalibration, suitable for remote installations.
Implementation Method 1
a magnet mounted on or relative to the valve member, wherein the magnet is arranged to be displaced by the displacement of the valve member in a direction parallel to the direction of displacement of the valve member; and a plurality of magnetic field sensors mounted at a plurality of different positions on the valve housing
Data Source
AI summary
A device for controlling the flow of a fluid through a conduit from an upstream side of the device to a downstream side of the device. The device includes a valve housing having defined therein a valve aperture, a valve member movably mounted relative to the valve aperture. The valve member is arranged to be displaced reciprocally in a direction to selectively open and close the valve aperture. The device also includes a magnet mounted on or relative to the valve member, with the magnet being displaced by displacement of the valve member. A plurality of magnetic field sensors are mounted on the valve housing.