Thermal measuring and testing – Transformation point determination
Patent
1990-07-24
1991-11-12
Cuchlinski, Jr., William A.
Thermal measuring and testing
Transformation point determination
374 25, 436147, G01N 2504
Patent
active
050642944
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a process for investigating and controlling changes of state of a liquid or gelled medium--for example of the gelling of a liquid fluid or the liquefaction of a gel, by differential measurement of thermal characteristics of the involved medium.
The invention is also aimed at a device for making use of this process. This invention applies more particularly to food industries.
BACKGROUND
A process for the application of the hot wire anemometry principle to follow milk coagulation is described in document EP-A-0-144,443. This method makes it possible more generally to follow a liquid-gel transition under isothermal conditions. In fact, energy is introduced into initially liquid medium in the form of heat by means of a platinum wire, after which a measurement of the temperature of this wire is carried out. In a liquid medium, natural convection produces an equilibrium of heat transfers between the wire and the product so that the wire temperature is constant, slightly higher than that of the surrounding medium. If the medium coagulates or gels, the change in the structure of this medium is accompanied by a change in the thermal regime with a changeover from natural convection to conduction. This is reflected in an increase in the temperature of the platinum wire, which corresponds to a change in the heat transfer coefficient in the medium, since the heat conductivity of the latter remains constant. In the food industry field, firstly, the isothermal state is never perfectly achieved and, secondly, many cases of gelling or of coagulation are coupled with a temperature change, for example the gelling of gelatin, of polysaccharides and, more generally, the manufacture of sauces and of jams, as also is the coagulation on heating of milk to which rennet has been added when cold, etc. In the cases set out above the perturbations introduced by the temperature change do not allow the sensor proposed in the abovementioned patent to display the coagulation phenomenon.
SUMMARY OF THE INVENTION
An object of the present invention is to take into account temperature changes in the medium which is capable of being coagulated or gelled in order to control and to investigate the changes of state of this medium.
Another object of the present invention is to employ these characteristics to obtain information relating solely to the coagulation phenomena in the strict meaning of the term.
The subject of the present invention is therefore a process for investigating and controlling the phenomena of gelling of a liquid fluid or of liquefaction of a gel by differential measurement of the thermal characteristics of the said medium, characterized in that the measurement of the temperature of the medium is carried out by means of a first probe delivering a first signal indicating the temperature of this medium, while contributing energy in the form of heat to the said medium by means of a second probe which is sufficiently far away from the first probe not to disturb the latter through the temperature changes, this second probe delivering a signal corresponding to its temperature, after which the signals emitted by the probes are processed, after amplification and correction, in an electrical data processing unit, using the medium temperature measurement signal to correct the signal supplied by the second heat quantity probe, so as to make the data contained in the signal relate to the coagulation phenomena in the strict meaning of the term.
The invention also extends to a device for sensing the thermal characteristics of a liquid fluid in the course of gelling, more particularly intended for making use of the abovementioned process, this device being characterized by the coupling of a first probe ensuring the measurement of the temperature of the liquid fluid and of a second probe intended to contribute energy in the form of heat to the medium, these two probes delivering signals which are transferred, after amplification and correction, to an electrical data processing uni
REFERENCES:
patent: 2922304 (1960-01-01), Lees et al.
patent: 3643491 (1972-02-01), Dell et al.
patent: 3675465 (1972-07-01), Sommer et al.
patent: 4040288 (1977-08-01), Kotelnikov et al.
patent: 4255962 (1981-03-01), Ashman
patent: 4567849 (1986-02-01), Wan
patent: 4601587 (1986-07-01), Mathiprakasam
patent: 4611928 (1986-09-01), Hori et al.
patent: 4663169 (1987-05-01), Hori et al.
patent: 4783174 (1988-11-01), Gmelin et al.
patent: 4812051 (1989-03-01), Paulik et al.
patent: 4967593 (1989-07-01), McQueen
patent: 4971451 (1990-11-01), Hori et al.
patent: 4981369 (1991-01-01), Kumada et al.
White, J. L. et al., "Application of Differential Thermal Colorimetry to Measurements of Stored-Energy Release in Metals", Rev. Scientific Instrum., vol. 34, No. 10, (Oct. 1963).
"Soviet Inventions Illustrated", Week E19, No. 6456 E/19 * SU 851222, 6/23/82.
Antonini Gerard
Cerf Olivier
Pain Jean-Pierre
Cuchlinski Jr. William A.
Gutierrez Diego F. F.
Institut National de la Recherche Agronomique
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