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Proceedings Paper

Fiber optic liquid level sensors for shipboard applications
Author(s): Henry K. Whitesel; John K. Overby; Christopher Peter Nemarich; Francois X. Desforges; Patricia A. Tatem; Carl P. Jacobson
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Paper Abstract

This paper discloses a new fiber optic differential pressure sensor for liquid level measurement and control. The intended application is for US Navy use in automated shipboard machinery control and monitoring and damage control systems. The sensor has been developed in response to the need for an inexpensive, yet rugged and reliable liquid level sensor, compatible with advanced automated control systems, and suitable for use in hostile and difficult environments. The sensor is developed from an existing commerical design of a low- finesse, short-cavity Fabry-Perot pressure sensor. The sensor consists of a glass micro-chip etched with a shallow, optical cavity capped by a pressure sensitive silicon diaphragm. The Fabry-Perot cavity is vented to the chip base so that a differential pressure can be developed across the diaphragm. The micro-chip is fused to the optical fiber and housed in a protective capillary tube. The differential pressure developed across the diaphragm changes the depth of the Fabry-Perot cavity. This is sensed by measuring the shift in the reflected spectrum of the source LED using a dichroic ratio technique. Experimental models of the senosrs have been evaluated successfully on a US Navy test ship, the ex-USS SHADWELL. Since it is a true differential pressure sensor, it can be used in both pressurized and unpressurized fluid tanks. The sensor's performance and cost attributes should make this technology suitable for many industrial process and control applications.

Paper Details

Date Published: 25 September 1995
PDF: 12 pages
Proc. SPIE 2510, Fiber Optic and Laser Sensors XIII, (25 September 1995); doi: 10.1117/12.221694
Show Author Affiliations
Henry K. Whitesel, Naval Surface Warfare Ctr. (United States)
John K. Overby, Naval Surface Warfare Ctr. (United States)
Christopher Peter Nemarich, Naval Surface Warfare Ctr. (United States)
Francois X. Desforges, Photonetics, Inc. (United States)
Patricia A. Tatem, Naval Research Lab. (United States)
Carl P. Jacobson, Naval Sea Systems Command (United States)

Published in SPIE Proceedings Vol. 2510:
Fiber Optic and Laser Sensors XIII
Ramon P. DePaula; John W. Berthold, Editor(s)

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