Measuring and testing – Sampler – sample handling – etc. – With heating or cooling
Patent
1997-03-19
1999-08-03
Raevis, Robert
Measuring and testing
Sampler, sample handling, etc.
With heating or cooling
220240, 219756, G01N 100
Patent
active
059328177
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a system for sealing at least one flask of longitudinal axis X-X' which is open at a first end for the introduction of a sample and which is positioned inside a microwave-application cavity with a view to heating the sample.
The invention also relates to apparatus for carrying out a treatment in a wet environment on a number of samples at the same time, the apparatus employing microwave heating of the samples and including such a sealing system.
Such apparatus finds a particularly advantageous use in carrying out chemical reactions such as mineralization, saponification, hydrolysis, speciation, and organic synthesis, for example.
Another particularly advantageous use of the apparatus according to the invention is the extraction under the effect of microwaves in a solvent of organic or inorganic compounds dispersed in soils, sediments, waters, plants, biological products or alternatively polymers.
In particular the invention relates to an improvement to the apparatus described in French patent applications nos 93 157 35 and FR 2 681 431 belonging to the Applicant Company, this apparatus including means for emitting microwaves into a microwave-application cavity of cylindrical shape operating in the open condition.
Already known apparatus of this type which operates in the closed condition, under pressure, generally comprises a microwave-application cavity in which bombs closed by screw-on caps are arranged.
This type of apparatus does, however, have several drawbacks.
This is because the bombs cannot contain large volumes of sample because the greater the volume of the sample, the more gas is given off under pressure when the sample is heated, which does not allow the bomb to work.
Furthermore, such apparatus working with bombs comprising screw-closure devices can work only in one condition, that is to say in the condition closed under pressure. It is not possible first of all to carry out degassing by making the apparatus work in the open condition then to close said apparatus to work under pressure.
The invention proposes a new sealing system which is fitted on a flask in a simple way allowing the flask to work in the open condition or closed condition, this making it possible to treat large volumes of samples by first of all carrying out an initial degassing operation before closing the flask.
More particularly, according to the invention, the sealing system includes: X-X' so as to seal its open end, said associated flask, that part of the stopper which is engaged in said flask including a peripheral skirt which can be pressed in leaktight fashion against the internal wall of the flask under the effect of an overpressure which there is in this flask once the sample has been heated by microwaves.
According to a preferred embodiment of the invention, the means of retaining the sealing system comprise a bearing surface which can be positioned at right angles to the axis X-X' above each stopper, the relative position of the bearing surface and of the stopper allowing the latter to slide inside the flask along the axis X-X' in the direction of the bearing surface so as to come to bear against the latter under the thrusting force induced by the overpressure which there is inside the flask upon heating of the sample.
Furthermore, advantageously, in the sealing system in accordance with the invention, the skirt of each stopper is fitted with a lip capable of pressing in leaktight manner against the internal wall of the associated microwave-heated flask under the effect of the internal overpressure.
In accordance with the preferred embodiment of the sealing system according to the invention, it includes a pressure sensor connected to the bearing surface and capable of recording the overpressure which there is inside said flask through the bearing surface bearing on the stopper.
Furthermore, according to this preferred embodiment, the bearing surface of the sealing system in accordance with the invention carries at least one detector capable of coming into contact with each stopper
REFERENCES:
patent: 2299401 (1942-10-01), Melton
patent: 3635370 (1972-01-01), Romanavskas
patent: 5095886 (1992-03-01), Schmed
patent: 5369034 (1994-11-01), Hargett et al.
patent: 5407641 (1995-04-01), Katschnig et al.
patent: 5427741 (1995-06-01), Bennett
patent: 5496110 (1996-03-01), Geier et al.
patent: 5542576 (1996-08-01), Arment
Raevis Robert
Societe Prolabo
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