Time-temperature monitor and recording device and method for using the same

Claim 1

A time and temperature monitor for indicating the amount of accumulated time during which the ambient temperature adjacent to said monitor is above a predetermined temperature, said monitor comprising: a viscous, non-Newtonian fluid wherein said viscosity of said fluid: (i) has a first value, when said viscous fluid's temperature is below said predetermined temperature, that prevents said viscous fluid from flowing under the influence of a biasing force, and (ii) has a second value, when said viscous fluid's temperature is above said predetermined temperature, that allows said viscous fluid to flow under the influence of said biasing force; means for defining a flow path for a portion of said viscous fluid wherein said means for defining a flow path is adapted to inhibit said viscous fluid from flowing at temperatures below said predetermined temperature, and also creates a terminal end portion of said viscous fluid; means for biasing said viscous fluid within said means for defining a flow path so as to provide said biasing force on said viscous fluid; means for viewing said terminal end portion of said viscous fluid; means for indicating a relative position of said terminal end portion over a plurality of time intervals, wherein said indicating means are disposed adjacent to said means for defining a flow path and further wherein said indicating means are calibrated so as to indicate the passage of time as a function of the rate of flow of said viscous fluid through said means for defining a flow path; and means for regulating the flow of said viscous fluid, disposed in fluid communication with said means for defining a flow path, said means for regulating the flow of said viscous fluid being adapted to provide a shearing force to said viscous fluid so as to constrain the flow thereof at temperatures above said predetermined temperature.

Claim 22

A method for monitoring the amount of accumulated time during which the ambient temperature adjacent to temperature sensitive item is above a predetermined temperature, said method comprising the steps of: (A) providing a time-temperature monitor comprising: a viscous, non-Newtonian fluid wherein said viscosity of said fluid: (i) has a first value, when said viscous fluid s temperature is below said predetermined temperature, that prevents said viscous fluid from flowing under the influence of a biasing force, and (ii) has a second value, when said viscous fluid's temperature is above said predetermined temperature, that allows said viscous fluid to flow under the influence of said biasing force; a transparent conduit comprising a first open end, a second open end, and a tapered central passageway adapted to inhibit said viscous fluid from flowing at temperatures below said predetermined temperature, and including a portion of said viscous fluid disposed within said passageway and having at least a terminal end portion of said viscous fluid visible therein, said conduit further comprising indicia positioned adjacent to the outer surface of said conduit, said indicia being adapted for indicating intervals of time; a chamber disposed adjacent to said second open end of said tapered conduit in sealed and pressurized fluid communication with said portion of said viscous fluid disposed within said tapered conduit, said viscous fluid being biased within said tapered conduit by a pressurized elastic fluid disposed within said chamber and said passageway; and a nozzle comprising an orifice adapted to apply a shearing force to said viscous fluid so as to control the flow of said viscous fluid out of said tapered conduit at temperatures above said predetermined temperature, said nozzle being disposed within a fluid receptacle disposed in fluid communication with said first open end of said tapered conduit, and further wherein an actuation pin is releasably engaged within said fluid receptacle and said orifice prior to activation of said monitor, said pin extending through, and sealingly engaging said orifice so that when said pin is withdrawn therefrom, said viscous fluid is free to flow through said tapered conduit, out of said orifice, and into said fluid receptacle under the influence of said pressurized elastic fluid; (B) conditioning said time-temperature monitor wherein said monitor is exposed to a temperature below said predetermined temperature for a time sufficient to establish thermal equilibrium therein and thereafter removing said conditioned monitor from said conditioning environment; (C) activating said monitor whereby said pin is removed from said orifice; (D) recording the position of said terminal end portion of said viscous fluid relative to said indicia; (E) placing said monitor adjacent to said perishable items; (F) transporting said perishable items; and (G) noting again the position of said terminal end portion of said viscous fluid relative to said indicia.

Claim 23

A method for monitoring the amount of accumulated time during which the ambient temperature adjacent to temperature sensitive item is above a predetermined temperature, said method comprising the steps of: (A) providing a time-temperature monitor comprising: a viscous, non-Newtonian fluid wherein said viscosity of said fluid: (i) has a first value, when said viscous fluid s temperature is below said predetermined temperature, that prevents said viscous fluid from flowing under the influence of a biasing force, and (ii) has a second value, when said viscous fluid's temperature is above said predetermined temperature, that allows said viscous fluid to flow under the influence of said biasing force; a transparent conduit comprising a first open end, a second open end, and a tapered central passageway adapted to inhibit said viscous fluid from flowing at temperatures below said predetermined temperature, and including a portion of said viscous fluid disposed within said passageway and having at least a terminal end portion of said viscous fluid visible therein, said conduit further comprising indicia positioned adjacent to the outer surface of said conduit, said indicia being adapted for indicating intervals of time; a chamber disposed adjacent to said second open end of said tapered conduit in sealed and pressurized fluid communication with said portion of said viscous fluid disposed within said tapered conduit, said viscous fluid being biased within said tapered conduit by a pressurized elastic fluid disposed within said chamber and said passageway; and a nozzle comprising an orifice adapted to apply a shearing force to said viscous fluid so as to control the flow of said viscous fluid out of said tapered conduit at temperatures above said predetermined temperature, said nozzle being disposed within a fluid receptacle disposed in fluid communication with said first open end of said tapered conduit, and further wherein an actuation pin is releasably engaged within said fluid receptacle and said orifice prior to activation of said monitor, said pin extending through, and sealingly engaging said orifice so that when said pin is withdrawn therefrom, said viscous fluid is free to flow through said tapered conduit, out of said orifice, and into said fluid receptacle under the influence of said pressurized elastic fluid; (B) conditioning said time-temperature monitor wherein said monitor is exposed to a temperature below said predetermined temperature for a time sufficient to establish thermal equilibrium therein and thereafter removing said conditioned monitor from said conditioning environment; (C) activating said monitor whereby said pin is removed from said orifice; (D) recording the position of said terminal end portion of said viscous fluid relative to said indicia; (E) placing said monitor adjacent to said perishable items; (F) transporting said perishable items; and (G) noting again the position of said terminal end portion of said viscous fluid relative to said indicia.