| 摘要 |
A sealed tube (1) contains an ampoule (4) and a granular indicating layer (5). The ampoule contains, for example, ethylene glycol on silica gel and the indicating layer (5) consists of chromosulphuric acid on silica gel. The glass tube (1) has a predetermined breaking point (8) and is covered with a shrunk-on flexible tube (9) which maintains the tube sealed. On bending the glass tube the ampoule is simultaneously broken and nascent ethylene glycol vapours enter the indicating layer (5) causing a progressive discolouration which is a measure of temperature and time. If the ambient temperature is known, the duration of temperature loads may be ascertained or, if the monitoring period is known, an average temperature may be ascertained. <IMAGE> |
