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The detection of bearing wear and leaks in gate valves and can be improved by means of
a new micromechanical silicon sensor. Both defects cause ultrasonic vibrations in the
structure.
Equipment defects, wear and the need for maintenance are easily revealed when a vibration
sensor is embedded in the device. Slightly thicker than a button battery, the sensor can
be used for dozens of different applications.
The new sensor is well suited to equipment self-diagnosis and remote condition monitoring
applications. Based on silicon-fabricated capacitance, it is lighter, smaller, more
sensitive and more robust than the piezoelectric sensors currently in use. The power
consumption of the sensor is low and it is economic to mass-produce.
Manufactured to be application-specific, the sensor detects vibrations at frequencies as
low as 1 MHz. The sensor's reading technology is so good that the accuracy of the device
is limited only by spontaneous vibration of the micromechanical membrane, i.e. Brownian
motion.
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The sensor has been made as a collaboration involving VTT Automation, VTT Electronics
and VTT Manufacturing Technology. The work has been funded by the National Technology
Agency (Tekes), Neles Automation and Fortum Service, and the project forms part of Tekes's
"Reliability as a Competitive Factor" technology programme. A follow-up project
is under way to commercialise the sensor.
Additional information: VTT Automation, Aarne Oja, tel. +358 9 456 6526 or 040 510
2487.