Patent ID: 6968804
Filing Date: 2005-11-29
Classification: G01K

Abstract:
1. A detector for detecting and measuring the exposure of an object to a predetermined temperature, said detector comprising: a substantially flat housing, said housing having a lower face and an upper face, said faces defining a propagation space located between said faces, said upper face being one of transparent and having holes therein; an enclosure operatively associated with said propagation space; a temperature responsive substance disposed in said enclosure, said substance changing states at a predetermined temperature; a porous opaque strip disposed in said propagation space, said strip becoming transparent when impregnated with said substance, said strip movable within said propagation space between first, non-enabled, position and a second, enabled, position; and a movable member secured to said porous strip, said porous strip selectively movable from said first non-enabled position preventing contact of said porous strip with said temperature responsive substance, to said second enabled position permitting contact of said porous strip with said temperature responsive substance, said enclosure enabled to communicate with said propagation space, whereby, when so enabled, said substance, upon changing states, impregnates a portion of said porous strip by capillary action at a predetermined speed and causes the impregnated portion of said strip to become transparent to thereby provide a quantitative indication of the duration and exposure of the detector to a temperature above said predetermined temperature.