Inventors:
Robert J. Bardoorian - New Britain CT
Assignee:
National Magnetic Sensors Inc. - Plantsville CT
International Classification:
G02B 636
G02B 726
Abstract:
A fiber optic liquid level sensor having a vertical tube which may be placed in a vessel containing the liquid to be sensed. Disposed for free movement along the exterior of the tube is an annular float equipped with a magnet. A fiber optic cable containing two optical fibers is attached to the top of the tube and the optical fibers extend to a selected point where it is desired to sense the liquid level. There the fibers terminate facing a movable mirror to which a magnet is attached. With a rising liquid level, the mirror is carried upward by the magnetic linkage of the magnet on the float and the magnet to which the mirror is attached. When the mirror reaches the focal point of the optical fibers, the light circuit is closed and an electrical signal derived therefrom may be used to open or close a switch. When the liquid level falls so that the mirror drops below the focal point of the optical fibers, the light circuit will be opened. The optical fibers are completely isolated from the environment of the liquid and, thus, the sensor may be used in hazardous locations.
