Sensor technology apples acoustic surface waves to measure torque

February 11, 2014 // By Christoph Hammerschmidt
Under the brand name TorqueSense, measurement technology company Althen (Kelkheim, Germany) is launching a torque sensor product family, based on IP from British company Sensor Technology.

Intended for use in industrial applications, the technology consists of an element that detects acoustic surface waves; a ceramic substrate excited at a nominal frequency. Torque changes cause this frequency to change, providing the detected parameter which is then signal-processed. The output signal - a current, voltage, RS232 or USB signal - is transferred contactlessly from the rotating shaft to the receiver. Complex and failure-prone installation of strain gauges can be eliminated.

TorqueSense offers a significantly lower signal noise level than strain gauges which typically use collector (slip) rings for signal transmission. TorqueSense offers a very broad measurement range from 1 to 13,000 Nm and is usable at rotational speeds up to 30,000 rpm.

First applications have been installed in fields such as power measurement of motors and testing of pumps of various sizes. In other applications the torque measurement is used to derive other physical values. For instance, it is used in research labs where the viscosity of substances is determined by means of stirrers, with a torque sensor attached to the stirrer shaft. Other application fields range from torque measurements at underwater turbines to the safe screw connection of medicine bottles.


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