The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 11, 1995
Filed:
Mar. 15, 1993
Andrew P Murphy, Littleton, CO (US);
Abstract
An indicator device indicates that the temperature in a location in which the device is placed has exceeded a predetermined maximum temperature value. The he device includes a liquid receptacle comprising frangible bulb portion and an integral capillary portion and an absorbent card to which said receptacle is secured. The bulb portion contains a first liquid and the capillary portion contains a second liquid which is insoluble in said first liquid. The second liquid has a freezing point higher then that of the first liquid and close to but greater than the predetermined temperature value so that when the device is placed in a location which has temperature lower than the predetermined value and in which the predetermined value is to be maintained, the second liquid freezes in the capillary tube and prevents the first liquid from expanding. Thus, if the temperature in the monitored location increases such that expansion of the first liquid causes breakage of the frangible bulb and the release of the first liquid that liquid will cause staining of the absorbent card to provide an indication that the predetermined value has been exceeded within the location.