Patent ID: 9279732
Filing Date: 2016-03-08
CPC Classification: G01K

Claim Text:
1. A temperature indicator comprising: a) a hollow tubular structure having an outer wall interposed between a first end and a second end, the outer wall defining a hollow interior having an inside wall; b) a float releasably held in place at a point on the inside wall of the tubular structure at or near the first end by a temperature dependent holding material that melts at or about a critical temperature, the temperature dependent holding material interposed between the first end and the second end, the float having a first density, wherein the temperature dependent holding material is a coating on the float that attaches the float to the inside wall of the tubular structure; and c) a fluid within the hollow interior, the fluid interposed between the second end and the float, the fluid having a second density that is greater than the first density, the fluid being a material different than the temperature dependent holding material, wherein when the temperature indicator is heated to or about to the critical temperature, the temperature dependent holding material melts and releases the float from the inside wall, whereby the float floats through the fluid towards the second end, and wherein the float is visible at or near the second end as an indicator that the critical temperature has been reached.