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US 4,979,797 AGranted
Multi-level fiber-optic liquid-level sensing system
AssigneeIMO Industries, Inc.
InventorFrank A. Nemeth
Life of this patent
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AssigneeIMO Industries, Inc.
InventorFrank A. Nemeth
Estimating the term…
Plural sensor prisms and associated opticalfiber circuits are arrayed as a single vertical stem by which the individual prisms serve for response to each of a plurality of different liquid levels. Each prism is formed of light-transmitting plastic material which can be injection-molded to precision dimensions. The body configuration is such as to adapt to arrayed interconnection with tubular members, also of plastic, and bonded at telescoping fit of each prism to the tubular member or members to which it is connected. The prism configuration relied upon for sensed response to the presence of immersing liquid (as compared to air) is a solid region having an exterior profile which includes a downwardly convergent conical surface portion at least at spaced locales which are at equal but opposite offset from the cylindrical body axis, wherein the geometric apex angle of downward convergence is 90 degrees. As long as a given prism is exposed to air, a large amount of light is transmitted (by reflection within the prism) from a transmission optical fiber to a receiving optical fiber. But when immersed in a liquid, a portion of the light from the transmitting fiber is refracted into the liquid, resulting in a clearly detectable decrease in the amount of light coupled to the receiving fiber.
A multi-level fiber-optic liquid-level sensing system, comprising upper and lower elongate tubular suspension members, an upper-level sensor connected to the lower end of said upper member and to the upper end of the said lower member, a lower-level sensor connected to the lower end of said lower member, and means for suspending the connected members and sensors from the upper end of said upper member, said sensors each being a solid cylindrical body of light-transmitting material with an exterior profile which includes a downwardly convergent surface portion at least at spaced locales which are at equal but opposite offset from the cylindrical body axis, the geometric apex angle of downward convergence being 90 degrees;
A liquid-level sensor body for use in a multi-level fiber-optic liquid level sensing system, said body being generally cylindrical and of light-transmitting material and adapted for suspension with its central axis in vertical orientation, there being intermediate upper and lower ends of said body an exterior profile reduction which is downwardly convergent at least at spaced locales which are at equal but opposite offset from the cylindrical body axis, the geometric apex angle of downward convergence being 90 degrees, the upper end of said body having a first pair of upwardly open like bores for optical-fiber reception on diametrically opposed axes that are parallel to the cylindrical body axis, the geometric downward projection of each of said bores having incidence with a different one of said spaced locales, said body having at least one through-bore at radial offset from a direct diametrically extending path between said spaced locales, and said body having a connection formation concentric with the cylindrical body axis at each of the upper and lower ends of said body.
A multi-level in-line fiber-optic liquid-level sensing system, comprising an interconnected array of generally cylindrical upper and lower sensor elements with interposed tubular connecting members, all on a single axis and adapted for vertical suspension, each of said sensors being a solid cylindrical body of light-transmitting material with an exterior profile which includes a downwardly convergent surface portion at least at spaced locales which are at equal but opposite offset from said single axis, the geometric apex angle of downward convergence being 90 degrees;
Dependencies are inferred from the claim text.