Fluorescent optical liquid level sensor

Patent · 31 December 2000

OSTI ID:873488

Weiss, Jonathan D ^[1]

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1. Albuquerque, NM

A liquid level sensor comprising a transparent waveguide containing fluorescent material that is excited by light of a first wavelength and emits at a second, longer wavelength. The upper end of the waveguide is connected to a light source at the first wavelength through a beveled portion of the waveguide such that the input light is totally internally reflected within the waveguide above an air/liquid interface in a tank but is transmitted into the liquid below this interface. Light is emitted from the fluorescent material only in those portions of the waveguide that are above the air/liquid interface, to be collected at the upper end of the waveguide by a detector that is sensitive only to the second wavelength. As the interface moves down in the tank, the signal strength from the detector will increase.

• Research Organization: SANDIA CORP
• DOE Contract Number: AC04-94AL85000
• Assignee: Sandia Corporation (Albuquerque, NM)
• Patent Number(s): US 6172377
• OSTI ID: 873488
• Country of Publication: United States
• Language: English

Related Subjects

/250/
air
below
beveled
collected
comprising
connected
containing
detector
emits
emitted
excited
fluorescent
fluorescent material
increase
input
input light
interface
internally
internally reflected
level
level sensor
light
light source
liquid
liquid interface
liquid level
material
moves
optical
portion
portions
reflected
sensitive
sensor
sensor comprising
signal
signal strength
source
strength
tank
totally
transmitted
transparent
upper
waveguide
wavelength