초록 ▼

A freeze and thaw indicator is provided utilizing the expansion characteristics of water when it undergoes a change from the liquid state to the solid state. An ampul having one side made weaker than its opposite side is substantially filled with water. Indicator paper having ink printed on one side

A freeze and thaw indicator is provided utilizing the expansion characteristics of water when it undergoes a change from the liquid state to the solid state. An ampul having one side made weaker than its opposite side is substantially filled with water. Indicator paper having ink printed on one side is situated adjacent to the ampul. The indicator paper and ampul are housed in a blister pack plastic container for protecting the ampul from breakage. When the temperature around the indicator reaches the freezing point of water, the ampul breaks. During a subsequent thawing, the water flows on to the indicator paper causing the ink which is printed on one side to wick up, thereby indicating that the freeze or thaw has taken place.

대표청구항 ▼

A device for indicating that an environment has reached or passed through the temperature near a freezing point of a liquid comprising: a frangible sealed ampul, a liquid being enclosed in said ampul, said liquid having the characteristic of expanding in volume at or near its freezing point, said am

A device for indicating that an environment has reached or passed through the temperature near a freezing point of a liquid comprising: a frangible sealed ampul, a liquid being enclosed in said ampul, said liquid having the characteristic of expanding in volume at or near its freezing point, said ampul having at least a first and a second face, said first face having an indentation projecting relatively close to but spaced from said second face inside of said ampul, said indentation forming a sharp acute angle inside of said ampul, said indentation performing the dual function of providing a site for encouraging crystal growth when said liquid is at or near its freezing point and further providing a mechanism for strengthening said first face of said ampul relative to said second face whereby said frangible, sealed ampul will consistently break upon the expansion of said liquid, thereby indicating that the environment has reached or passed through a temperature near the freezing point of said liquid. A freeze-thaw indicator comprising: a frangible ampul; a porton of the inner surface of said ampul being irregular for promoting crystal growth; a material in said frangible ampul adapted to undergo a phase change at a predetermined temperature, said material undergoing volumetric expansion as it passes below said predetermined temperature in going to a solid phase rupturing said ampul; a nucleating agent contained by said ampul for further promoting crystal growth; a blister pack including a top portion and a bottom portion, said top portion of said blister pack including at least one raised portion, said frangible ampul being contained by said blister pack; said raised portion protecTing said ampul from mechanical shock.