| 摘要 |
<p>A temperature recorder, e.g. for indicating the length of time that frozen food has been defrosted, comprises a reservoir 22 of coloured liquid which breaks upon freezing, and a track 20 arranged for the indicator liquid to migrate along when the liquid subsequently thaws. The position to which the liquid migrates along the track 20 gives an indication of the length of time for which the temperature of the frozen food has been above the melting point of the indicator liquid.</p> |
