Freeze-thaw indicator with a liquid-filled frangible ampul
CA 1095340 A · Owner: Akzona Incorporated · Inventors: Couch, Thomas W.; Harvey, James A.; Mercer, Howard A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
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, …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted February 10, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 10, 1998.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.