Battery-Free Flow Meter With Nested Wiegand Sensors
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Solution Overview
Problem
Existing battery-free meters for flowing media face challenges such as lack of redundancy, susceptibility to external magnetic interference, and unsuitability for aggressive media due to exposed moving parts and magnetic coupling issues.
Innovation Solution
A design featuring a rotating sleeve with permanent magnets generating a transverse magnetic field that penetrates two Wiegand sensors inside a housing, allowing for redundant systems, shielding from external interference, and eliminating the need for external power, with Hall sensors for rotation direction detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single Wiegand sensor is used outside the flowing medium, then the device complexity is reduced, but the reliability is insufficient due to lack of redundancy
Solution Approach 1:
The patent divides the sensing function into multiple independent Wiegand sensors (at least two) arranged in the housing, each capable of independently detecting the rotating magnetic field. This segmentation allows redundancy while keeping each sensor simple and independent, resolving the contradiction between device complexity and reliability.
Solution Approach 2:
The patent implements redundant Wiegand sensors as a backup system before failure occurs. If one sensor fails, the other continues to provide measurement capability, cushioning against the harmful effect of sensor failure and maintaining system reliability without requiring complex active monitoring.
2Force
If permanent magnets are exposed outside the housing, then the magnetic field strength is improved, but the system becomes susceptible to external magnetic interference
Solution Approach 1:
The patent nests the permanent magnets inside the housing, with the magnetic field penetrating through the housing wall to reach the Wiegand sensors. This nested arrangement protects the magnets from external magnetic interference while maintaining sufficient field strength for sensor operation, resolving the contradiction between magnetic field strength and susceptibility to interference.
3Device complexity
If moving parts are arranged outside the flowing medium, then the measurement function is simplified, but the system becomes vulnerable to manipulation and wear
Solution Approach 1:
The patent places the rotating component with permanent magnets inside the sealed housing, nested within the flowing medium environment. The magnetic field passes through the housing wall to the sensors, keeping moving parts protected from external manipulation and wear while maintaining the measurement function.
Solution Approach 2:
The patent replaces direct mechanical contact between moving parts and sensors with magnetic field coupling. The Wiegand sensors detect the rotating magnetic field without mechanical contact, eliminating wear and vulnerability to manipulation while maintaining measurement capability.
4Ease of operation
If magnetic coupling is used to transmit rotation across the medium boundary, then the measurement function is achieved, but the system becomes easily influenced by external magnetic fields
Solution Approach 1:
The patent extracts the Wiegand sensors from the external magnetic coupling arrangement and places them inside the housing where they directly detect the rotating magnetic field from the permanent magnets. This eliminates the intermediate magnetic coupling stage that is vulnerable to external interference, achieving measurement while reducing susceptibility to external magnetic fields.
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 design enhances reliability, reduces wear, and prevents external manipulation, enabling accurate flow measurement in aggressive media without batteries or calibration, while minimizing housing size and external exposure.
Implementation Method 1
a disc (1) fitted with permanent magnets and driven in rotation by the fluid flow
Implementation Method 2
The Wiegand sensor required to generate electrical energy
Implementation Method 3
The Wiegand sensor required to generate electrical energy
Implementation Method 4
a housing part sealingly engaging in the interior of the pipeline transversely to the longitudinal axis of the pipeline
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Battery-free meter for flowing media, in which a rotor body (sleeve 4) which is fitted with permanent magnets (6, 7) and is driven in a rotary fashion by the medium is arranged in the pipeline (34) carrying the flowing medium (8) and in which the rotating magnetic field generated by this acts on at least one Wiegand sensor (25, 26), which is arranged outside the flowing medium in the area around the meter, wherein a housing part (15) which is open on at least one side sealing to the interior of the pipeline (34) engages with the pipeline (34) and around which the flowing medium at least partially flows, such that the external periphery of the housing part (15) is at least partially embraced by the rotor part (sleeve 4) which is driven in a rotary fashion and generates the rotating magnetic field and that at least one Wiegand sensor (25, 26) is arranged in the housing part (15).