Patent ID: 6761066
Filing Date: 2004-07-13
Classification: G01F

Abstract:
A level indicator which is intimately affixed to the outside surface of the outside wall of a container for use in determining the level of the interface between a mass of flowable material and the void volume above said mass of flowable material within a container;wherein said flowable material within the container has fluidic properties, and said flowable material has a faster rate of heat transfer than said void volume above it within the container; said level indicator being in the form of an elongated strip, vertically extending along the height of the container, wherein said level indicator conforms to the contour of the outside surface of the outside wall of the container such that said level indicator is in intimate heat transfer relationship with the outside wall of the container; wherein said at least two thermochromatic materials are directly applied to the outside surface of the outside wall of the container; wherein at least a portion of the outside surface of the outside wall of the container which underlies said level indicator has been treated by an application method chosen from the group consisting of anodizing, anti-oxidizing, rust-proofing, and combinations thereof, so as to provide at least that portion of the outside surface of the outside wall with a light absorbing property, prior to the direct application of said level indicator to the outside surface of the outside wall of the container; wherein said level indicator includes a thermochromatic layer, said thermochromatic layer has at least two thermochromatic materials, and said at least two thermochromatic materials are arranged in at least two regions; wherein each of said at least two regions of thermochromatic materials is arranged in an individual area, and each of said thermochromatic materials responds chromatically within a different operating temperature range; and wherein said regions of said at least two thermochrornatic materials are disposed in arrays thereof arranged along the length of said level indicator.