The irreversible temperature indicators are based on a fusible heat-sensitive wax technology. The technology basically consists of a series of temperature-sensitive elements sealed between heat-resistant layers which, in turn, contain transparent windows to reveal the colour changes.
Each element changes colour when its calibration temperature is exceeded. The changes are irreversible, so they provide a temperature record of the surface being monitored. The labels are not damaged when peeled off and can be attached to an inspection report to serve as proof of the temperature reached. They are normally used for industrial applications.
How do irreversible temperature indicators work?
The heat-sensitive elements built into these strips are phase-change indicators made from organic chemical substances whose melting points have been carefully defined to provide unique, highly accurate colour changes.
Each temperature uses a different chemical component and, in turn, each component is sealed with a coating that isolates it on a special absorbent paper substrate, normally black. When each calibration temperature is exceeded, the chemical substance in question melts and is absorbed by the substrate, causing the final black colour. Up to 10 elements can be combined in a single strip (THERMAX 10 Levels).
