US 5,142,909 AGranted

Material level indicator

OwnerJames S. Baughmaninventor

Life of this patent

Estimating the term…

Loading patent…

Abstract

A system for indicating level of material in a vessel comprising a probe which includes a plurality of electrically discrete probe elements of electrically conductive construction position within a material vessel in a spaced array extending height-wise of the vessel. Each probe element has electrical characteristics which vary as a function of proximity of material thereto within the vessel. In one embodiment, the probe elements comprise capacitive elements responsive to varying dielectric characteristics as material approaches each element. In another embodiment, having particularly utility in fuel level sensing applications, the probe elements comprise resistance elements responsive to cooling through immersion in fuel for varying voltage drop thereacross. Electonic circuitry is coupled to the several probe elements for detecting material level as a function of electrical characteristics of the probe elements. Preferably, such level detection is accomplished in discrete steps corresponding to separation between probe elements.

Claims8

Dependent claims

A system for indicating level of material in a vessel comprising:

resistance probe means including a plurality of electrically discrete resistor probes of electrically conductive construction positioned within the vessel in a spaced array extending height-wise of the vessel, said probes being characterized by having electrical resistances which vary as a function of heat dissipative coupling with material in the vessel,
said resistance probe means comprising a continuous layer of resistance material on a planar rectangular substrate, said resistance layer being of serpentine contour height-wise of the vessel, and first and second opposed electrical contact means positioned in alternate undulations of said resistive layer height-wise of the vessel, said resistance layer and said contact means being carried on one face of said substrate,
said first contact means comprising a first array of contacts extending from one edge of said substrate and being interconnected by an electrical bus which extends along said edge, said second contact means comprising discrete second contacts extending from an opposing edge of said substrate,
first circuit means individually connected to said discrete probes and being responsive to variation of said electrical characteristics, and
second circuit means coupled to said first circuit means and responsive to total variation of said electrical characteristics collectively at said probes for indicating level of material in the vessel adjacent to said probes.

2 more elements

A system for indicating level of material in a vessel comprising:

a probe which includes a continuous strip of electrical resistance material on a substrate and extending height-wise of the vessel, and first and second arrays of electrical contacts disposed along opposite sides of said strip on said substrate, contacts of said first and second arrays being electrically alternately connected to said strip height-wise of the vessel,
first circuit means including means connecting all contacts of said first array to a source of electrical power, means individually coupled to contacts of said second array and responsive to electrical resistance characteristics of individual sections of said strip between said alternately-connected contacts of said first and second arrays as a function of heat dissipative coupling of said strip sections to material in the vessel, and
second circuit means coupled to said first circuit means and responsive to total variation of said resistance characteristics of said strip section connected in parallel to said first circuit means for indicating level of material in the vessel adjacent to said probe.

Dependencies are inferred from the claim text.