End of life indicator for automatic toilet cleaning devices
US4800066A · kind A · utility
14Cited by
16References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1986 |
| Grant date | Jan 24, 1989 |
| Priority date | — |
| Expiry date | Jul 21, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N31/22
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An end of life indicator for use in a toilet cistern with an ambient solution containing an active disinfectant component. The end of life indicator comprises a core of water soluble dyestuff surrounded by a polymer resistant to bleaching by said disinfectant solution. Upon the depletion of the active disinfectant component surrounding the end of life indicator, the alkalinity of the solution increases to a predetermined level whereupon hydrolysis of the polymer coating continues until water penetrates or dissolves the coating sufficiently to come into contact with the water soluble dye.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.