A wireless flow sensor based on magnetic higher-order harmonic fields

Document Type

Article

Publication Date

11-9-2009

Abstract

The design and fabrication of a wireless, passive flow sensor based on changes in magnetic higher-order harmonic fields is described. The sensor consisted of a flow channel, a permanent magnetic strip (biasing element) and a magnetically soft ferromagnetic strip (sensing element). The biasing element was attached on the channel's wall in parallel to the flow direction, while the sensing element was applied on the opposite wall at a small angle to the flow direction. Flowing water in the channel created a pressure on the sensing element's surface, causing a deflection that varied its separation distance from the biasing element. The change in the separation distance in turn altered the biasing field experienced by the sensing element, causing a shift in its higher-order harmonic fields that could be measured remotely through a magnetic coil. The novelty of this sensor is its wireless, passive nature, which is ideal for applications where wire connections are prohibited. In addition, this sensor can be used on a disposable basis due to its simple design and relatively low material cost. © 2009 IOP Publishing Ltd.

Publication Title

Smart Materials and Structures

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