Multifunctional time-temperature indicator
US5057434A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 1989 |
| Grant date | Oct 15, 1991 |
| Priority date | — |
| Expiry date | Aug 29, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S252/962
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An accurate monitoring of the conditions of a perishable product is achieved by integrating two indicator types - a primary indicator which develops a color change as a result of cumulative time-temperature exposure and a threshold second indicator - into a single device. The combination of the two indicators in the same indicator device provides a human readible signal that gradually and irreversibly develops color as a function of time and temperature and more closely monitors the actual condition of a deteriorative product than does a single indicator. Important features of this integrated monitoring device are reliability and printability. The primary indicator in the system is assisted in color development by the secondary indictor that is set to trigger at a predetermined temperature. When this temperature is reached or exceeded both indicator mechanisms function in an additive mode to cause a break in the typical Arrhenius curve, which a primary indicator alone produces. This can be used to signal actual rather than an apparent the end of a product life. The secondary indicia can be formulated to change very rapidly as would be needed to detect the thawing of a frozen produc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.