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Proceedings Paper

Long-life fiber optic pressure sensors for monitoring and control of gas machinery
Author(s): Tom Poorman; Jacob Arnold; Terry Coleman; Marek T. Wlodarczyk
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Paper Abstract

In a robust, durable, and low-cost design Optrand pressure sensors utilize the principle of light intensity changes, transmitted by two optical fibers, upon reflection from a specially shaped, metal diaphragm deflecting under the effect of pressure. The non-contact detection principle combined with the diaphragm design optimized for infinite fatigue life translates into a sensor with extraordinary lifetime. The sensor's signal conditioner contains one LED and one photodiode and is permanently attached to the fibers. The electronic circuitry provides the auto- referencing function compensating for the effects of fiber bending, fiber-to-optoelectronics coupling changes, sensor thermal drift, as well as temperature and aging effects of the LED and the photodiode. The results of several along- term test in two key gas machinery applications are reported here: continuous and intermittent monitoring of power and compressor cylinders. In the longest application to date, hundreds of combustion pressure sensors have demonstrated over 12,000 hours or 500-million pressure-cycle lifetime. Dynamic pressure sensors for compressor monitoring have already demonstrated the lifetime of 1 billion cycles and target 5 billions. In compressor applications the sensor demonstrate typical +/- 0.25 percent accuracy while combustion pressure sensor accuracy is typically +/- 1 percent. For almost two years tens of indicator valve- mounted combustion sensor have been monitored for calibration stability demonstrating better than +/- 0.1 percent performance over a 6-month period.

Paper Details

Date Published: 11 January 1999
PDF: 8 pages
Proc. SPIE 3538, Process Monitoring with Optical Fibers and Harsh Environment Sensors, (11 January 1999); doi: 10.1117/12.335754
Show Author Affiliations
Tom Poorman, Optrand, Inc. (United States)
Jacob Arnold, Optrand, Inc. (United States)
Terry Coleman, Optrand, Inc. (United States)
Marek T. Wlodarczyk, Optrand, Inc. (United States)

Published in SPIE Proceedings Vol. 3538:
Process Monitoring with Optical Fibers and Harsh Environment Sensors
Michael A. Marcus; Michael A. Marcus; Anbo Wang, Editor(s)

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