Patent ID: 7429126

Claim:
A residual lifetime device for a perishable consumer product, comprising a material which displays a property variable with varying temperature in accordance with a given function; actuating means which acts on said material so as to make it exhibit said property; and indicator means linked to said material and said actuating means, said indicator means indicating the residual lifetime relative to an expiry date of the product; wherein said material is a fluid ( 102 ; 114 ) having a viscosity variable as a function of the temperature; said material flows in a first pipe ( 2 , 212 ; 4 , 134 ) having a cross-section; said actuating means comprises a device ( 311 , 601 , 411 , 701 ; 313 , 203 , 113 , 204 ) capable of applying an essentially constant pressure on said fluid ( 102 , 114 ), the flow of said fluid being linked to said indicator means ( 701 , 413 ); and said indicator capable of applying a constant pressure on said fluid ( 102 , 114 ) comprises a solvent/solution osmotic couple ( 311 , 411 ; 313 ; 113 ) separated by a semipermeable membrane ( 601 ; 203 ) and connected, via mobile separation means ( 302 , 701 ; 204 , 304 ) positioned at the ends of containing means ( 301 , 401 ; 403 , 303 , 103 ) of said osmotic couple ( 311 , 411 ; 313 ; 113 ), to the two ends of the first pipe ( 2 ; 4 ) in which the fluid ( 102 ; 104 ) having variable viscosity is placed.