US 2002/0157464 A1 · External liquid level gauge

Abstract

An external liquid level gauge may be provided for determining the level of the interface between a mass of flowable material and the void volume above it within a container. The external liquid level gauge is adapted to be affixed vertically to the outside wall of the container, extending along substantially the entire height. It is in the form of an elongated strip and comprises a layer of base material and a layer of thermochromatic materials. The thermochromatic layer further comprises a light absorbing background and at least two regions of thermochromatic materials which are arranged upon the light absorbing background. The regions of at least two thermochromatic materials are disposed in arrays thereof and are arranged entirely along the length of the external liquid level gauge. Moreover, each of the thermochromatic materials is arranged in an individual area and each thermochromatic material responds chromatically within a different operating temperature range. The theory is that the rate of heat transfer is different between a mass of flowable material and the void volume above it such that for any container with a modest heat conducting capability, the container wall experiences a temperature gradient which is most pronounced at and below the interface of the contents. Thus, with the use of thermochromatic materials, a vivid color change occurring at and below the interface will permit an observer to obtain a direct reading of the level of the flowable material within a container.

Claims21

Dependent claims

An external liquid level gauge which is adapted to be affixed vertically to the outside wall of a container for use in the determination of 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 external liquid level gauge is adapted to extend along substantially the entire height of the 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 external liquid level gauge being in the form of an elongated strip which comprises a layer of base material and a layer of thermochromatic material;
wherein said layer of base material is adapted to be secured to the outside wall of a container in intimate heat transfer relationship with the outside wall of a container;
wherein said thermochromatic layer overlies said layer of base material;
said thermochromatic layer comprising a light absorbing background, and at least two regions of thermochromatic materials being arranged upon said light absorbing background;
wherein each of said at least two regions of thermochromatic materials is arranged in an individual area upon said light absorbing background and each of said thermochromatic materials responds chromatically within a different operating temperature range;
and
wherein said regions of said at least two thermochromatic materials are disposed in arrays thereof arranged entirely along the length of said external liquid level gauge in the vicinity between the bottom end of said gauge and the top end of said gauge.

6 more elements

A method of 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 using an external liquid level gauge;

wherein said flowable material within said container has fluidic properties;
and said flowable material has a faster rate of heat transfer than said void volume above it within said container;
wherein said external liquid level gauge is affixed vertically to the outside wall of said container;
wherein said external liquid level gauge extends along substantially the entire height of said container;
said external liquid level gauge being in the form of an elongated strip comprises a layer of base material and a layer of thermochromatic material;
wherein said layer of base material is secured to said outside wall of said container in intimate heat transfer relationship with said outside wall of said container;
wherein said thermochromatic layer overlies said layer of base material;
said thermochromatic layer comprising a light absorbing background, and at least two regions of thermochromatic materials being arranged upon said light absorbing background;
wherein each of said at least two regions of thermochromatic materials is arranged in an individual area upon said light absorbing background and each of said at least two thermochromatic materials responds chromatically within a different operating temperature range;
wherein said regions of thermochromatic materials are disposed in arrays thereof arranged entirely along the length of said external liquid level gauge in the vicinity between the bottom end of said gauge and the top end of said gauge;
said method comprising the steps of:
(i) inducing heat transfer between said external liquid level gauge and said mass of flowable material within said container;
(ii) discerning visually a color change in said at least one region of said array of said external liquid level gauge;
(iii) wherein said region which responds chromatically to a temperature change is contiguous to said mass of flowable material within said container;
wherein step (i) is achieved by any of the steps chosen from the group of steps consisting of:
(a) spraying a liquid onto the entire surface of said external liquid level gauge affixed to said outside wall of said container;
(b) wetting the entire surface of said external liquid level affixed to said outside wall of said container with a moistened cloth or sponge;
(c) pouring a liquid down the entire surface of said external liquid level gauge affixed to said outside wall of said container;
(d) trickling a liquid down the entire surface of said external liquid level gauge affixed to said outside wall of said container;
and
(e) applying an electrically energized source along the entire length of said external liquid level gauge affixed to said outside wall of said container.

18 more elements

Dependencies are inferred from the claim text.

External liquid level gauge

Life of this patent

External liquid level gauge

Life of this patent

Abstract

Claims21