| abstract |
This invention comprises a reusable temperature recording telltale for cryogenic refrigerators, and in particular a telltale for use in a cryogenic refrigerator with racks for the storage of ampules, vials or other containers. The telltale device consists of an ampule, vial or other similar container which contains a liquid which has a melting-freezing point at a definite known temperature. This contained liquid within the ampule is frozen in a first orientation, and placed in the cryogenic refrigerator in a second orientation, but since frozen, it maintains its first orientation. However, if the cryogenic refrigerator achieves a temperature above the melting-freezing point of the contained liquid, it takes up the second orientation, recording the temperature excursion. Further, when a series of ampules containing liquids have varying meltingfreezing points, the temperature excursion can be closely calculated, and when used in combination with a rack which maintains the orientation within the refrigerator, there is no possibility of an erroneous reading. |