초록 ▼

Device for indicating a critical temperature, such as, for example, the freezing point of a liquid. The device comprises a sheet which is a layer having a multiplicity of micropores therein and a mixture comprising at least two liquids, said mixture incapable of wetting said sheet at a given tempera

Device for indicating a critical temperature, such as, for example, the freezing point of a liquid. The device comprises a sheet which is a layer having a multiplicity of micropores therein and a mixture comprising at least two liquids, said mixture incapable of wetting said sheet at a given temperature, but capable of wetting said sheet when the temperature of said mixture reaches a critical value, such as the freezing point of one of the liquids in the mixture. The micropores, or voids, in the microporous layer cause scattering of transmitted light, causing the microporous layer to appear opaque. When the voids are filled with a liquid having substantially the same index of refraction as the material of the microporous layer, the filled voids do not scatter transmitted light, thus rendering the microporous layer transmissive to visible light. A visible indicator is associated with the layer of microporous film such that at a temperature above the freezing point of the liquid composition, the visible indicator is masked by the layer of microporous film, but at a temperature at or below the freezing point of the liquid composition, the liquid wets out the layer of microporous film, thereby allowing the visible indicator to be seen through the layer of microporous film.

대표청구항 ▼

A device for indicating the freezing point of a liquid comprising: a. a layer of film having a multiplicity of micropores therein, b. a barrier layer sealed to said layer of microporous film at the periphery thereof to form a receptacle between said barrier layer and said layer of microporous film,

A device for indicating the freezing point of a liquid comprising: a. a layer of film having a multiplicity of micropores therein, b. a barrier layer sealed to said layer of microporous film at the periphery thereof to form a receptacle between said barrier layer and said layer of microporous film, c. a liquid composition disposed in said receptacle, said composition comprising at least two liquids, one of said liquids having a surface energy sufficiently low that it is capable of wetting out the micropores of said microporous layer, the other of said liquids having a surface energy insufficiently low that it is incapable of wetting out the micropores of said microporous layer, whereby above the freezing point of said liquid having insufficiently low surface energy, the mixture will not wet out the micropores of said microporous layer, but at or below the freezing point of said liquid having insufficiently low surface energy, the mixture will wet out the micropores of said microporous layer.