# US 5,707,590 A · Detergent container with thermo-chromatic level indicator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,590 A - Document ID: US5707590A - Status: Granted - Kind: A - Application number: 08/538,734 - Filed: 1995-10-03 - Granted: 1998-01-13 - Earliest claimed: 1993-08-25 - Assignees: Ecolab Inc. - Inventors: John E. Thomas; Jody A. Toetschinger; John E. McCall, Jr.; Eric R. Balz - Web page: https://patentgrep.com/patent/US5707590A ## CPC - G01F 23/22: by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water (involving the use of floats G01F23/30) - A47L 15/4436: {in the form of a detergent solution made by gradually dissolving a powder detergent cake or a solid detergent block} - B01F 21/22: {using additional holders in conduits, containers or pools for keeping the solid material in place, e.g. supports or receptacles} - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - A47L: DOMESTIC WASHING OR CLEANING (brushes A46B; cleaning quantities of bottles or of other hollow articles of one kind B08B9/00; laundry D06F); SUCTION CLEANERS IN GENERAL (cleaning in general B08) - B01F: MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING (mixing paints B44D3/06) ## Abstract Disclosed is an indicator (15, 35) for determining the level of contents in an opaque, plastic container (10, 30, 40). The container (10, 30, 40) is filled with a solid chemical (11), such as a detergent. A spray of warm or hot water (19) impinges upon the eroding surface (16) of the solid chemical (11) to produce a chemical solution. The container (10, 30, 40) is provided with a thermo-chromatic strip (15, 35) or thermo-chromatic surface (41) for detecting the level of solid chemical (11) within the plastic capsule (10). A method of manufacturing the dispensing container (10, 30, 40) is also disclosed. ## Claims ### Claim 1 A detergent-containing article of commerce having internal and external surfaces, comprising: (a) a container being made of an opaque plastic material, said container having an internal layer and an external layer, both of said layers being made of a plastic material; (b) a solid chemical within said container, said chemical being a detergent, said container surrounding and in contact with the detergent on all but one surface thereof, said one surface being an eroding surface; and (c) a thermo-chromatic substance dispersed throughout said external layer of said container, said thermo-chromatic substance being selected so as to exhibit a color change of said external layer at the level of said eroding surface responsive to a warm water spray onto said eroding surface of said chemical and onto said internal surface of said container. ### Claim 2 (depends on 1) The article of claim 1, wherein said internal layer and said external layer are formed by a coextrusion process. ### Claim 3 (depends on 1) The article of claim 1, wherein said inner layer extends across all internal surfaces of said container. ### Claim 4 (depends on 1) The article of claim 1, wherein the color change of said thermo-chromatic additive is reversible. ### Claim 5 (depends on 1) The article according to claim 1, wherein said water spray has a temperature of about 120.degree. F. or greater. ### Claim 6 (depends on 1) The article according to claim 1, wherein said thermo-chromatic substance has a temperature activity point ranging from about 100.degree. F. to 180.degree. F. ### Claim 7 (depends on 1) The article according to claim 1, wherein said thermo-chromatic additive has a mesomorphic range of approximately 104.degree. F. to 122.degree. F. ### Claim 8 (depends on 1) The article according to claim 1, wherein said thermo-chromatic additive has a mesomorphic range of approximately 111.degree. F. to 136.degree. F. ### Claim 9 A method of manufacturing a container which contains a solid block of chemical within an upper portion of said container, said container having at least one internal surface, said solid chemical being a detergent for the washing of dishes, ware, laundry or hard surface, the method comprising the steps of: (a) providing a first plastic material, approximately ten percent of said first material comprising a thermo-chromatic additive; (b) providing a second plastic material containing no thermo-chromatic additive; (c) combining said first and second plastic materials as outer and inner layers, respectively, in a coextrusion process so as to form a hollow container; and (d) filling said container with the solid chemical, said chemical having an eroding surface, said thermo-chromatic additive being selected so as to exhibit a color change at the level of said eroding surface responsive to a warm water spray. ### Claim 10 (depends on 9) The method according to claim 9, wherein said second plastic material forms said inner layer which extends across said internal surfaces of said container.