Abstract: A time temperature indicator for measuring elapsed time after reaching a threshold temperature includes a reservoir containing an indicator fluid that may be solid below the threshold temperature and that liquefies above the threshold temperature. Activation enables a flow of liquid from the reservoir to reach a migration medium so that when the temperature of the indicator exceeds the threshold temperature after activation liquid migrates through the migration medium producing a colour change therein. A narrow passage is foldable along and parallel to a longitudinal axis thereof so as to form a barrier to liquid migration when the passage is folded while permitting liquid migration through the passage when the passage is unfolded. A micro-fluid valve may be likewise constructed for regulating a flow of liquid between an inlet and an outlet coupled by a narrow passage foldable along and parallel to a longitudinal axis thereof.

Abstract: A device for indicating that an ambient temperature has fallen to or below a predetermined lower threshold temperature. The device includes: a porous membrane having first and second spatially separate zones; a first freezable liquid infused in the porous membrane, the first freezable liquid having a freezing point corresponding to the predetermined lower threshold temperature; a second liquid for contacting the first zone of the porous membrane, the second liquid being immiscible with the first liquid; and an indicator window for indicating migration of the second liquid from the first zone to the second zone. The membrane infused with the first liquid is impervious to the second liquid above the threshold temperature and is permeable to the second liquid at or below the threshold temperature. The device is useful in applications where products degrade below a certain lower threshold temperature.

Abstract: The invention provides an electronic printed chromatic elapsed time indicator device comprising a switch, a power source and a power driven elapsed time display for indicating the elapse of a limited predetermined segment of time upon activation of the switch and irrespective of the actual time of activation thereof, wherein the components are functionally interconnected and are printed on at least one substrate.

Abstract: A time indicator comprising a first reservoir (13), a migration medium (11) and activating means for bringing liquid from the first reservoir (13) in contact with the migration medium (11) so that after activation the liquid migrates through the migration medium (11) producing a colour change therein. The activating means comprises a second reservoir (16) connected between the first reservoir (13) and the migration medium (11) whereby after activation the liquid travels relatively rapidly from the first reservoir (13) to the second reservoir (16) and then migrates relatively slowly along the length of the migration medium (11) over time.

Abstract: The invention provides an electronic printed chromatic elapsed time indicator device comprising a switch, a power source and a power driven elapsed time display for indicating the elapse of a limited predetermined segment of time upon activation of the switch and irrespective of the actual time of activation thereof, wherein the components are functionally interconnected and are printed on at least one substrate.