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Method of using a thermo-chromatic detergent level indicator

  • US 5,385,044 A
  • Filed: 08/25/1993
  • Issued: 01/31/1995
  • Est. Priority Date: 08/25/1993
  • Status: Expired due to Term
First Claim
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1. A method of monitoring the level of a solid block of chemical which is positioned within an upper portion of an opaque container and which includes an eroding surface within said container, said container being made of a plastic material and having an internal surface and an external surface, said container including a thermo-chromatic substance, said thermo-chromatic substance being an additive to the plastic material from which said container is formed, the method comprising the steps of:

  • (a) spraying warm water within said container onto said eroding surface of said solid block of chemical and onto said internal surface, said thermo-chromatic substance being selected so as to exhibit a color change of said container at the level of said eroding surface responsive to said step of spraying with warm water; and

    (b) observing said color change of said container to determine the level of said eroding surface and thereby determine when said container is substantially empty.

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