Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
  • G01K11/06—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using melting, freezing, or softening
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K3/00—Thermometers giving results other than momentary value of temperature
  • G01K3/02—Thermometers giving results other than momentary value of temperature giving means values; giving integrated values
  • G01K3/04—Thermometers giving results other than momentary value of temperature giving means values; giving integrated values in respect of time

Definitions

• the present invention concerns systems for the assessment of the influence of variations in temperature on perishable products and in particular concerns a residual lifetime indicator device for consumer products, in particular for food products.
• a time-temperature indicator is described wherein a small bar of a given material is subjected to a traction load, for example from a spring, and the given material is capable of varying its response to the traction depending on the temperature.
• a traction load for example from a spring
• the stretchable material and the means for subjecting it to a traction load it is possible to obtain a device which provides information concerning the residual lifetime of the product to which the said device was linked.
• this type of solution presents a series of difficulties connected mainly with the selection of the materials in question; in the first place, considerable difficulties in calibrating the indicator can also arise.
• the purpose of the present invention is thus to provide a device which is capable of providing an indication, easily readable by the consumer, of the residual life-time of the production with indication of the expiry date, adaptable to products of varying nature, capable of providing a reliable and non-reversible indication, and of low production cost; further, the device must be made of non-toxic materials, must be of modest size and difficult to tamper with.
• the object of the present invention is thus a residual lifetime indicator device for perishable consumer products, comprising a material which displays a property variable with variation of the temperature according to a given function, actuating means which act on the said material so as to make it exhibit the aforesaid property, and indicator means linked to the material/ actuating means combination, said indicator means indicating the residual lifetime with respect to the expiry date of the product; said material is a fluid of viscosity varying as a function of the temperature, which flows in a pipe of a given cross-section, the actuating means comprising a device capable of applying an essentially constant pressure onto said fluid, the flow of said fluid being linked to said indicator means.
• Said device capable of applying a constant pressure on said fluid can comprise a solvent/solution osmotic couple separated by a semipermeable membrane and connected, via two mobile means of separation located at its ends, to the two ends of the pipe in which the fluid of variable viscosity is located.
• the said indicator device comprises a chamber which contains: a saline solution separated from the solvent by a semipermeable membrane, and connected, via an impermeable mobile partition, to the said fluid of variable viscosity; means capable of causing a localised pressure drop which open into a pipe connected to the end of the said chamber in which the solvent is located, a mobile and impermeable partition being positioned between said fluid of variable viscosity and said solvent; the mobile partition positioned between the saline solution and the fluid of variable viscosity can function as an indicator means.
• the fluid of variable viscosity is a fluid of high viscosity, of the order of thousands of centipoises.
• the fluid of variable viscosity is immiscible with the osmotic couple, and the interface between the immiscible phases can constitute the indicator means.
• Figure 1 is a schematic representation in plan of a first practical form of the indicator device according to the present invention
• Figure 2 is a view in plan of a second practical form of the device of the invention; and Figure 3 is a perspective view of the device illustrated in Figure 2.
• FIG. 1 a first practical form of the device according to the present invention is shown schematically: 1 indicates a container, equipped at its ends with two apertures 101 and 201 connected to the pipe 2.
• the container 1 is subdivided within into a series of chambers; the semipermeable membrane 601 separates the chamber 301 , in which the pure solvent 31 1 is contained, from the saline solution 41 1 contained in the chamber 401.
• the partition 302 which represents the other end of the chamber 301 is mobile and its other face is turned towards the chamber 21 1 connected to the aperture 201 turned towards the pipe 2.
• the partition 701 which defines the chamber 401 is also mobile, and bounds the chamber 501 in which the viscous fluid 102 is contained, which is connected, via the septum 202, to the chamber 1 1 1 and hence to the pipe 2 via the aperture 101.
• the purpose of the indicator device of the invention is to provide a measurement of the passage of time assigning different weightings to the intervals of time passed at different storage temperatures of the product to which the device is attached.
• the mobile partition 701 located between the chamber 401 and the chamber 501 is displaced towards this latter chamber by the osmotic pressure caused by the passage of the solvent 311 towards the saline solution 41 1.
• the displacement of the mobile partition 701 is also a function of the viscosity of the fluid 102, which is pushed, by the action of the mobile partition 701 , through the channels or the channel 212 of the partition 202 into the pipe 2.
• the fluid must display a considerable variation in viscosity with varying temperature, so that its flow is appreciably affected by even minimal variations; the viscosity must decrease with increasing temperature, such that the indicator, namely the mobile partition 701 , moves more quickly when the temperature increases.
• the said fluid must moreover have a viscosity which is at any rate very high, of the order of several thousands of centipoises, so that the forward movements of the indicator are very slow.
• the fluids which display higher viscosity values are also those which undergo the effect of increasing temperature to a greater extent; in the cases illustrated here, the use of glycerine, which displays viscosity values lying between 1 1 ,000 centipoises at 0°C and 950 centipoises at 25°C was preferred.
• Vw specific molar volume of the solvent
• T temperature
• L length of the minichannel 212 of the partition 202
• r radius of the minichannel 212
• the practical form of the device described above in fact has a number of disadvantages: in the first place, the mobile partition which functions as the indicator could be subject to friction in its movement, and hence the indication provided could be less accurate than theoretically predicted. Moreover, it can be difficult to find the saline solution under saturation conditions which is appropriate to the duration for each specific product, bearing in mind also the non-toxicity requirements that the device will have to meet.
• a second practical form of the indicator device according to the present invention is shown schematically: in the support sheet 10, preferably of pressable material, a chamber 103 is formed, which contains a saline solution 113, connected via a semi-permeable membrane 203 to a chamber 303 containing the solvent 313 of the same solution, in this case water.
• the chamber 303 is connected via an aperture 323 to the pipe 403, in which is positioned the mobile indicator 413, in this case an air bubble.
• a flexible membrane 204 is located, which transmits the variations in pressure in the chamber 103 to the viscous fluid 104, which flows from the portion 144 of the chamber 103, via the aperture 104 and the capillary duct 134 made in the septum 124, into the pipe 4.
• an expansion chamber 404 subdivided into two parts by the flexible membrane 304, which in fact separates the viscous fluid 114 from the solvent 313 contained in the pipe 403, which is connected to the chamber 404 via the aperture 423.
• the pressure is transferred from the osmotic couple to the viscous fluid and from this again to the solvent of the osmotic couple, but this time across flexible membranes.
• These membranes i.e. the membranes 204 and 304, must be capable of presenting minimal resistance to the pressure exerted on them, and hence must display an essential zero tension.
• the indicator 413 can be created, as described, as an air bubble inserted into the solvent, which can be suitably coloured to provide an appropriate means of contrast.
• the chamber 404 can be filled, from the part facing the pipe 403, with a liquid immiscible with water, and preferably coloured, in such a manner that the interface between the two liquids functions as an indicator for the device according to the present practical form of the invention.
• the velocity of displacement of the indicator in the pipe 403 can be calculated according to the following equation: 2RA C S V»ST v. (2 )
• the indicator will move in the pipe at a velocity comparable to that found for the device according to the first practical form of the invention.
• the geometry utilised in this practical form makes it possible to obtain a practically constant osmotic effect without the need to use a saline solution under saturation conditions.
• the initial volume of the saline solution is much greater than the volume of water displaced in the complete travel of the indicator, which may be about 3-8% of the initial volume of the solution. Consequently, the fall in osmotic pressure due to the dilution of the saline solution is of the order of about 3-8% relative to the osmotic pressure measurable at the start.
• This effect can confidently be regarded as negligible, with the consequence that any saline solution can be used at the desired concentration: this allows a more manageable and wider calibration range for the device.
• FIG 3 an indicator device created in accordance with the practical form described above is illustrated: the same numbers correspond to the same components.
• the chamber 303 for the solvent, the chamber 103 for the solution, the compensating chamber 404 and the pipes 4 and 403 have been pressed in a single operation in the sheet 10 of pressable material.
• the chamber 303 is semicylindrical, just as the chamber 103 is a semicylindroid which at one end has a hemi-spherical segment; the chamber 404 is hemispherical and the pipes 4 and 403 are semicylindrical.
• the semi-permeable membrane 203 and the flexible membranes 204 and 304 are inserted in the appropriate positions.
• the semicylindrical septum 124 in which the capillary 134 is created eccentrically, is located at the entrance of the pipe 4.
• a graduated reference scale 1 1 In the plane of the sheet 10, close to the edge of the pipe 403, executed in one piece with the sheet 10 or applied onto the same, is located a graduated reference scale 1 1 , so as to improve the readability of the indication provided.
• a layer of rigid, transparent material 12 is then positioned, which provides protection and renders tampering with the said device almost impossible.
• the viscous fluid is immiscible both with the solvent and with the solution used in the indicator device of the invention; in this case it will be possible to avoid installing the mobile impermeable partitions intended to separate the viscous fluid from the solvent/solution couple.
• the interface between the viscous fluid and the solvent will itself constitute the indicator means, and for this purpose the solvent or the viscous fluid can be given an appropriate colouration, so as subsequently to make the indication provided prominently visible.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Measuring Temperature Or Quantity Of Heat (AREA)
• Measuring Fluid Pressure (AREA)
• General Preparation And Processing Of Foods (AREA)
• Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
• Packages (AREA)
• Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
• Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=36617376

Family Applications (1)

Country Status (7)

Cited By (3)

Families Citing this family (5)

Citations (4)

Family Cites Families (12)

• 2005
  • 2005-06-03 IT IT000037A patent/ITGE20050037A1/it unknown
• 2006
  • 2006-03-21 WO PCT/EP2006/060908 patent/WO2006128746A1/en not_active Ceased
  • 2006-03-21 AT AT06725195T patent/ATE509259T1/de not_active IP Right Cessation
  • 2006-03-21 EP EP06725195A patent/EP1886108B1/en not_active Not-in-force
  • 2006-03-21 CN CN200680019586XA patent/CN101203736B/zh not_active Expired - Fee Related
  • 2006-03-21 JP JP2008514040A patent/JP4707741B2/ja not_active Expired - Fee Related
• 2007
  • 2007-11-22 US US11/944,455 patent/US7429126B2/en not_active Expired - Fee Related

Patent Citations (4)

Non-Patent Citations (1)

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