Magnetostrictive Sensor for Hydraulic Fan Blade Position
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Solution Overview
Problem
Existing mechanical position indicators for hydraulic displacement mechanisms in axial-flow fans are imprecise and prone to wear due to mechanical connections.
Innovation Solution
A magnetostrictive displacement-measuring device is integrated into the hydraulic displacement mechanism, comprising a sensor housing, wave guide, sensor head, and annular magnet, which provides precise, absolute measurements without contact and wear, adapted for the hub space of axial-flow fans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical position indicator is used to indicate blade position, then the structure is simple and easy to install, but the measurement precision deteriorates due to mechanical connection wear
Solution Approach 1:
The patent replaces the mechanical position indicator system with a magnetostrictive displacement measuring device. The mechanical connection between the position indicator and the displacement mechanism is substituted by a non-contact magnetostrictive sensor that measures displacement through magnetic field interaction, eliminating wear and improving both precision and reliability.
Solution Approach 2:
The patent introduces a magnetostrictive waveguide as an intermediary element between the displacement mechanism and the sensor. The waveguide transmits displacement information through magnetostrictive deformation caused by magnetic field changes, enabling non-contact measurement while maintaining accuracy and eliminating mechanical wear.
2Reliability
If a mechanical connection is used to convey position information, then the device complexity is low, but wear occurs in the connecting parts
Solution Approach 1:
The patent eliminates mechanical connections by replacing them with a magnetostrictive sensing system. The sensor detects displacement through non-contact magnetic field interaction with the displacement mechanism, removing wear-prone mechanical links while maintaining functional capability.
Solution Approach 2:
The magnetostrictive waveguide serves multiple functions simultaneously: it acts as both the sensing element and the transmission medium for displacement information. The system is self-contained, requiring no external mechanical connections or additional components, thereby reducing overall device complexity while improving reliability.
3Measurement precision
If a mechanical position indicator is used, then the installation is straightforward, but the measurement values are not absolute and require reference marks
Solution Approach 1:
The patent replaces the mechanical indicator system with a magnetostrictive sensor that provides absolute displacement measurements. The sensor measures the actual displacement distance from a defined zero point without requiring mechanical reference marks or periodic calibration, enabling absolute measurement while maintaining ease of installation through non-contact coupling.
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 offers high precision, low linearity tolerance, and reproducible measurements, eliminating wear and ensuring accurate blade position adjustments in axial-flow fans.
Implementation Method 1
a magnetostrictive displacement-measuring device (24) that includes a sensor housing (25) having a wave guide (26), a sensor head (27), and an annular magnet (28), wherein the displacement mechanism is coupled to the displacement-measuring device
Data Source
AI summary
A device for measuring the displacement travel of a hydraulic displacement mechanism for blades of an impeller of an axial-flow fan, wherein the displacement mechanism includes as components a displacement cylinder and a piston rod having a piston, one of the components being axially displaceable and the other component not being axially displaceable. Respective spindles of the blades are secured to a displacement disk to which is connected the axially displaceable component of the displacement mechanism. An oil transfer element surrounds an extension of the piston rod that extends out of the displacement cylinder. A magnetostrictive displacement-measuring device that includes a sensor housing with a wave guide, sensor head, and an annular magnet is coupled to the displacement mechanism. The sensor housing and the sensor head are connected to the oil transfer element. Either the oil transfer element or one of the displacement mechanism components is axially displaceable relative to the other component. The magnet is connected to that component for which the axial displacement relative to the oil transfer element exists.