An optical-based differential pressure (DP) flow sensor has been developed
for an optically-powered hydraulic valve monitoring and feedback control sy
stem. The DP sensor employs two optical fibre single-mode Bragg grating ele
ments, which are mounted on either side of the DP sensing diaphragm. The fl
uid flow-rate signal is obtained in the form of differential optical wavele
ngth shift, and temperature compensation is provided. The sensor has been t
ested at fluid flow-rates from 0 to 800 cm(3)/s with temperature varying fr
om 25 to 75 degreesC. The optically-powered hydraulic valve using the DP fl
ow sensor as a monitoring system has been tested with hydraulic oil with a
flow-rate up to 6 cm(3)/s at a pressure of 700 kPa. (C) 2001 Elsevier Scien
ce B.V. All rights reserved.