Patent · US Expired

Humidity indicators

US6753184B1 · kind B1 · utility

3Cited by
7References
19Claims
0Family size

Assignee

Inventors

Key dates

Filing dateOct 22, 2001
Grant dateJun 22, 2004
Priority date—
Expiry dateOct 22, 2021

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG01N31/222
  • WIPO fieldMeasurement
  • WIPO sectorInstruments

Abstract

Silica-based carrier impregnated with iron(III) or iron(II) salts functions as a humidity indicator giving a yellow/amber to nearly colourless colour change as the carrier humidifies.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.