Irreversible Warmup Indicators.

摘要

Irreversible warmup indicators indicating in the 10 -15 c region were developed and prototypes manufactured. The device comprises a gelatin capsule filled with an organic liquid which freezes at the temperature to be indicated. The liquid contains a dye and the capsule is maintained in contact with absorbent paper. When frozen the contraction of the liquid draws air in through the joint in the capsule and upon thawing a portion of the liquid is exuded through the joint, coloring the paper and thereby providing the desired indication. Practical tests, including attachment to blood bags, establish a reliability of better than 98%. (Author)