FR2811586A1 - Sealed evaporator-condenser for preparing laboratory samples has evaporation and condensing containers arranged in inverted V with interconnecting openings in common plane - Google Patents

Abstract

A sealed evaporator-condenser has an evaporation container (2) and a condensing container (3) arranged in an inverted V-shape with interconnecting openings (2',3') arranged along a separation plane. A heater (7) raises a whole surface of a wall (6) of the evaporator to a higher temperature than a wall (5) of the condensing chamber. Preferred Features: The two containers may be identical translucent or transparent cylinders. The cylinders are removably fitted into the opposite ends of a 30-150 deg , preferably 90 deg elbow that includes the separation plane.

Description

- 1 -

DESCRIPTION

  The present invention relates to the field of laboratory apparatus, especially those used for the preparation of samples

  intended for chemical analysis and in particular that of evaporators-

  condensers. It relates to a device for evaporation and condensation in a closed environment. In qualitative and / or quantitative chemical characterization, particularly solid bodies, it is almost always necessary to prepare the samples before carrying out the analysis.

  proper to determine its composition.

  A conventional preparation process in chemistry is known as a "wet process" and consists in dissolving the organic or inorganic substances to be examined using solvents or suitable reagents in order to "release" the species that can be detected. and measured in physicochemical or isotopic measurement instruments usually employed (HPLC, NMR, IR spectrophotometry, atomic absorption ...). For inorganic solid compounds, particularly concentrated and aggressive inorganic reagents, such as strong acids or mixtures of strong acids, bases or mixtures, are generally used.

  strong bases which, moreover, must sometimes be heated.

  With regard to the solvents usually used to dissolve organic compounds, these are often harmful, even

  toxic for humans and their environment.

  The final result of the dissolution of the sample (and any subsequent chemical steps such as neutralization, filtration, precipitation, solvent substitution ...) is therefore a liquid solution of a greater or lesser volume than is necessary to reduce in order to concentrate the "released" substances to be analyzed. In some cases, it may even be necessary to completely eliminate the liquid (s) used in the sample preparation to obtain what is known as

a dry residue.

  This concentration operation is conventionally carried out by heating said solution in a suitable container and by evaporating the liquids or solvents under an extraction hood and / or using evaporators. Known evaporators are, for example, evaporators fed by a specific gas flow or rotary evaporators which allow to recover and recycle at least a part of

solvents and reagents evaporated.

  Evaporations in an "open" environment, however, pose a lot of problems in terms of safety and respect for the environment because the vapors of the solvents or chemical reagents contained in the solutions to be concentrated are generally harmful for the health of the environment. manipulator, for equipment (pipes, filters ...), even dangerous (risk of fire or explosion) Increasingly stringent environmental standards also imply the implementation of neutralization and filtration devices complexes of solvent-laden air that is sucked by the hoods and / or charged gases

  leaving gas-stream evaporators before being released into the atmosphere.

  In addition, air or gases entering the fume hood or evaporators may pollute the sample to be analyzed, which may lead to subsequent erroneous measurements, particularly when detecting present in trace amounts. In some cases it may thus be necessary to ensure that the air or the incoming gases are adapted to the nature of the solution to be treated and / or particularly pure, which

is neither practical nor economical.

  Although the evaporators fed by a specific gas flow avoid the dissemination of the evaporated reagents in the extraction hood, their use remains constraining in that it involves the

  handling of samples in series.

  Rotary evaporators also have many disadvantages. Relatively sophisticated, they are small, difficult to maintain, fragile to handle and, because of their complexity, relatively expensive. Moreover, they are not suitable for the evaporation of certain particularly corrosive inorganic reagents such as the acid

hydrofluoric, for example.

  The present invention is intended to overcome these disadvantages. For this purpose, it relates to a device for evaporation and condensation in a closed medium consisting essentially of an evaporation vessel, a heating means of said evaporation vessel and a condensation vessel connected in a substantially sealed to said 3 - evaporation vessel, characterized in that said evaporation and condensation vessels are interconnected at their openings, extending on either side of a common separation plane so that the arrangement of said containers substantially forms an inverted "V" with a sharp top and in that substantially the entire surface of the wall forming the evaporation container is carried by said heating means at the same temperature Tl higher than the highest T2 temperature of the wall forming the condensation vessel.

  The invention will be better understood thanks to the following description

  which relates to preferred embodiments, given by way of non-limiting examples, and explained with reference to the appended diagrammatic drawings, in which: FIG. 1 schematically represents a sectional view of a first example of embodiment of the device according to the present invention; Figure 2 shows, schematically, a sectional view of a second embodiment of the device according to the present invention; FIG. 3 schematically represents a perspective view of the device according to FIG. 2, and Figures 4a to 4d show simplified diagrams of the operation of the device according to the present invention; According to the invention, and as can be seen in FIG. 1, the device 1 for evaporation and condensation in a closed medium consists essentially of an evaporation vessel 2, a heating means 7 of said vessel 2 and a condensation vessel 3 substantially sealingly connected to said vessel

Evaporation 2.

  According to a first embodiment shown in section in FIG. 1, the device 1 according to the present invention is characterized in that said evaporation and condensing containers 2 are connected to one another at their openings 2 ', 3 ', extending on both sides of a common plane of separation 4 so that the arrangement of said containers 2, 3 substantially forms a "V" inverted with a bright top and in that substantially all the The surface of the wall 6 forming the evaporation vessel 2 is carried by said heating means 7 at the same temperature T1, which is higher than the highest temperature T2 of the

  wall 5 forming the condensation vessel 3.

  The materials constituting the evaporation vessel 2 and the condensation vessel 3 and / or the realization of the connection between said containers 2, 3 are chosen so as to withstand the reactants and solvents

  used to process the sample to be analyzed.

  The solution S to be concentrated is poured into the evaporation vessel 2 while the condensation vessel 3 is provided to collect the condensate C which accumulates therein as the solution S is evaporated. The device 1 thus makes it possible to condense the reagents or

  solvents just after evaporation.

  Completely insulated from the external environment, the device 1 according to the invention does not use a gas flow sweep on the solution S to be concentrated in order to evacuate the vapors emitted during the evaporation of

  Said solution S containing the substances to be analyzed.

  It thus makes it possible to carry out all the current operations

  evaporation and condensation economically and safely.

  The device 1 according to the invention makes it possible in particular to avoid the emission, in the ambient air of the laboratory and then into the atmosphere, of substances harmful to the health of the manipulator, the technical installations and the environment. The condensation of the solubilization reagents evaporated in the form of condensates C in the condensation vessel 3 makes it possible to recover the latter in a concentrated form for storage or

  of their treatment before disposal or recycling.

  The device 1 according to the invention makes it possible to work, if necessary, under extractor hoods operating at low airflow and does not require or few measures for treating the flow of air evacuated by said hoods. It thus allows an economy in the construction of the laboratories and in their cost of operation. It also reduces the energy consumption of existing hoods that no longer need to run at full speed during such manipulations. In addition, the device 1 according to the invention eliminates the possible contamination of the samples by the air or the gas flow sweeping the

  surface of said samples being evaporated.

  - The device 1 is also easier to use than the existing evaporator and more flexible in that it allows to treat

  the samples to be concentrated individually.

  In a second embodiment shown in FIG. 2, the device 1 according to the present invention is characterized in that the evaporation 2 and condensation 3 containers are connected, at their openings 2 ', 3', by the intermediate of a bent piece 8 to stop

  straight lines in which is the common plan of separation 4 '.

  Unlike the first embodiment described above in which the evaporation 2 and condensation 3 containers were directly connected to each other, for example by screwing, gluing, welding or the like, the evaporation 2 and condensation 3 containers are here connected

  through a bent piece 8.

  This measurement makes it possible, in particular, to mount and dismantle the device 1 more easily, for example to supply, empty, change, repair or clean the evaporation and condensation containers 2 and 3 mentioned above. According to another advantageous characteristic, the surface of the section of the evaporation vessel 2 located near the common separation plane 4, 4 'is less than or equal to the area of said common separation plane 4, 4'. This optimization of the surface of the common separation plane 4, 4 'makes it possible to increase the speed of execution of the operation of

  concentration and thus increase the economic profitability of the device 1.

  As previously mentioned, a particularly preferred embodiment of the present invention is characterized in that the evaporation 2 and condensation 3 containers are removably attached to the bent piece 8, for example by providing screw threads on the walls 6, 5 of said containers 2, 3 and of said bent piece 8. Of course, all the other usual modes of temporary fixing can also be envisaged (snap connection, hooks, fasteners, nuts ...) and the various fasteners may be provided, if necessary, with adequate sealing means, such as seals, membranes or the like. According to another characteristic of the present invention, the device 1 is characterized in that the evaporation 2 and condensation 3 containers are identical. This advantageously makes it possible to invert if necessary or if desired, the evaporation 2 and condensation 3 containers. This feature also makes it possible to reduce the quantities of evaporation 2 and condensation 3 containers stored in reserve. Particularly advantageously, the device according to the invention is characterized in that the angle A existing between the arms of the inverted "V" formed by the longitudinal axes of the evaporation and condensing containers 3 is between 30 and 150, and preferably equal to about 90, which allows for a reasonable space to obtain sufficient flow rates condensates

  C along the walls 5 of the condensation vessel 3.

  According to another characteristic, the evaporation vessel 2 and / or the condensation vessel 3 are in the form of cylindrical tubes. It is thus possible to use standard equipment or sufficiently close to the standard laboratory equipment to handle the solution S or the condensate C before or after the use of the device 1 according to the

present invention.

  As explained above, the cylindrical tube (s) may be provided with means for screwing the tube (s) into the workpiece

bent 8.

  As represented by way of non-limiting examples in FIGS. 1 to 3, the device 1 is still advantageously characterized in that the evaporation container 2 is entirely contained in a thermal enclosure 9, 9 'of adjustable temperature, the common plane 4, 4 'of the evaporation 2 and condensation 3 containers being located at the level and

  in the plane of one of the walls 10 of said thermal enclosure 9, 9 '.

  Thus, the common separation plane 4, 4 'which is common to the evaporation and condensing containers 2 and which delimits the surface from which the evaporated liquid can condense, can be, as can be clearly seen in FIGS. FIGS. 1 to 3, located in the vertical plane of one of the vertical walls of the thermal enclosure 9, 9 ', the coldest part (condensation vessel 3 and unheated portion 8 "of the bent piece 8)

  being located outside said thermal enclosure 9, 9 '.

  As shown in FIG. 2, a particularly advantageous variant of the device 1 is characterized in that the thenrmic enclosure 9 is heat-insulated on at least its wall portion 10 located near the condensation container 3 by means of at least one layer 11 of

  thermally insulating and / or chemically inert material.

  If said at least one layer 11 of insulating material is not sufficiently resistant to chemical attack, it may advantageously be in turn covered by an additional protective layer 12 of said layer 11 made of a chemically

  more suitable, for example a fluoropolymer of the PTFE type.

  In this way, it is avoided to damage the layer 11 by

  insulating material during a possible leakage of steam or aggressive liquid.

  In addition, this extra layer of protection 12 prevents the risks

burns in the user.

  Thanks to this insulation, the evaporation vessel 2 (and possibly the heated part 8 ') are better maintained at the temperature T1. Similarly, the difference between the temperature Ti of the evaporation vessel 2 and the maximum temperature T2 of the vessel 3 can be kept high, which contributes to

  further improve the performance of the device 1.

  The use of the ambient atmosphere as a cooling means for the condensation vessel 3 is particularly advantageous, both economically and conveniently and with regard to the safety of use with respect to any additional cooling device. . The addition of additional cooling means, for example a water cooler or a chemical cooler, remains possible, however, particularly if one wants to

  further improve the performance of said device 1.

  With regard to the material constituting the evaporation container 2 and the heated part 8 'of the bent piece 8, a material resistant to the corrosive chemical substances used in the context of the solubilization of the samples to be analyzed (H2SO4, HNO3) will be chosen. , HF, HCl, H3PO4, NaOH, KOH ...), and preferably a strong material

thermal conductivity.

  The condensation vessel 3 and the unheated portion 8 "of the bent piece 8 will advantageously be made of a resistant material

  also to the corrosive substances mentioned above.

  Materials suitable for making the unheated portion 8 "

  of the bent piece 8 are, for example, quartz, fluorinated polymers ...

  8 - Of course, the bent piece 8 can also be made in one piece in a single chemically resistant and inert material,

  for example a fluoropolymer of the PTFE type.

  FIG. 3 represents a perspective view of an evaporator and condenser device comprising a plurality of devices 1 (which is shown as the visible parts for the sake of clarity) according to the present invention. The four devices 1 are arranged in the form of modules in a single thermal enclosure 9 '. The inside of such a single thermal enclosure 9 'can for example be filled or made from a solid block of a material that conducts the heat traversed by electrical resistors and completely envelops all or substantially all the walls 6 of the device. evaporation vessel 2 (optionally the heated portions 8 'of the bent piece 8) in order to obtain a homogeneous temperature T1 on said walls 6 and parts 8' and inside said evaporation vessel 2. The graphite is, for example, particularly suitable for

  make a solid heating block for a single thermnnic enclosure 9 '.

  As can be seen in FIGS. 4a to 4d, the device 1 according to the present invention operates schematically in the manner

detailed below.

  The solution to be evaporated S is introduced into the evaporation vessel 2 of the device 1 by means of any feed means (not shown) such as an opening

  resealable, a connection to an external tank ...

  In the case where the evaporation container 2 is removable, the liquid to be evaporated can simply be poured manually into said container before being put or put back on the device 1, in particular fixed on the bent piece 8. Containers Removable evaporation 2 and condensation 3 are particularly useful when the nature of the solution to be evaporated is caused to change frequently or when cleaning is necessary. Removable containers 2, 3 also allow easier and faster replacement, for example in the event of deterioration of one of said containers or to adapt the volume or the physicochemical properties of said containers to the quantity or the nature of the solution.

S to evaporate.

  When the solution S is in place in the evaporation container 2, the bent piece 8 provided with the condensation container 3 can be fixed on said evaporation container 2, for example by screwing -9- or clipping, making sure of a good sealing between the different connected elements. The outer wall 6 of the evaporation vessel 2, if appropriate the wall of the heated portion 8 'of the bent piece 8, are then brought into contact over all or substantially all their surface with the means of

heating 7.

  In the non-limiting embodiments illustrated in FIGS. 1 to 4, the evaporation container 2 is introduced into a thermal enclosure 9, 9 'whose inner shape perfectly matches said evaporation container 2, thus ensuring an intimate thermal contact . As can be seen very clearly in FIG. 2, the condensation vessel 3 and the wall of the unheated portion 8 "of the bent piece 8 are not heated by the heating means 7 and are thus located at temperatures below that T1 prevailing in said evaporation vessel 2 when

  said heating means 7 is turned on.

  It should be noted that unlike the evaporation vessel 2, the condensation vessel 3 is not at a single temperature but that a thermal gradient is established inside said condensation vessel 3, whose maximum temperature T2 is less than T1 for

  that condensation since take place.

  The temperature T1 is regulated and regulated by means of the heating means 7 so that the constituents to be extracted from the solution S evaporate, without causing harmful boiling within said solution S. A range of adequate temperatures can, by

  for example, be between 40 C and 300 C depending on the solutions S to be treated.

  As can be seen in FIGS. 4a to 4d, the moderate heating (quivering) of the solution S causes the appearance of drops of

  condensates C on the colder walls of the condensation vessel 3.

  As illustrated, these drops are born only on the left side around the top of the top inverted "V" and slide along the wall of the condensation vessel 3 (more or less quickly depending on the angle of inclination A and the internal constitution of the wall 5 of the condensation vessel 3) to accumulate in the form of a condensate

  C at the bottom of the condensation vessel 3.

  As shown in FIGS. 4c and 4d, the particular geometry in the form of "V" inverted at a sharp angle of the device 1 makes it possible to prevent drops of condensate C formed at the top of the upside-down "V" from falling backwards. under the effect of their own weight in solution S to evaporate. Indeed, the aforementioned sharp angle makes it possible to separate and maintain on either side of the common separation plane 4, 4 ', the condensed drops intended to be collected at the bottom of the condensation vessel 3 and the non-condensed vapors of the 2. The tip of the upside-down "V" therefore forms a kind of upper groove acting as a one-dimensional linear boundary on which

  no (three-dimensional) drop can form.

  Likewise, the sharp angle of the inverted lower "V", close to the bottoms of the evaporation 2 and condensation 3 containers, forms a lower sharp edge acting as a second one-dimensional boundary for the condensed drops that have formed on the left part of the upper groove formed by the upper inverted "V", since these do not

  can only fall on the right side of the common plan of separation 4, 4 ', that is,

  ie in the bottom of the condensation container 3. The process

  evaporation is greatly accelerated.

  Finally, the device 1 according to the present invention also allows greater flexibility in the measure o evaporation can be done on large volumes of solution S. The device 1 of the present invention thus provides a evaporator-condenser both simple and powerful and that is easy and safe

to use and maintain.

  It goes without saying that the device 1 according to the present invention is preferably made of materials meeting the aforementioned requirements for chemical resistance to attack caused by the reagents or chemical solvents that may remain in the solution S to be evaporated and preferably, the usual requirements for

thermal conduction.

  Such materials can be chosen from a varied range such as, for information purposes, different types of glasses, plastics (in particular fluoropolymers such as PTFE), metals or

special alloys ...

  According to another particularly useful characteristic, the material used for the manufacture of the evaporation and / or condensation vessel (s) 2 is a transparent or translucent material.

  allowing a visual control of the levels in said containers 2, 3.

- he -

  Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications are possible, particularly from the point of view of the constitution of the various elements or by substitution of equivalent techniques, without leaving out

  of the field of protection of the invention.

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Claims (11)

  1. Evaporation and condensation device in a closed medium consisting essentially of an evaporation vessel, a heating means of said evaporation vessel and a condensation vessel substantially sealingly connected to said evaporation vessel , characterized in that said evaporation (2) and condensation (3) containers are interconnected at their openings (2 ', 3'), extending on either side of a common separation plane (4, 4 ') so that the arrangement of said containers (2, 3) substantially forms an inverted "V" with a sharp top and in that substantially the entire surface of the wall (6) forming the evaporation container (2) is carried by said heating means (7) at the same temperature T1 higher than the temperature T2   higher wall (5) forming the condensation container (3).   2. Device according to claim 1, characterized in that the evaporation containers (2) and condensation (3) are connected, at their openings (2 ', 3'), through a room elbow (8) with edges   straight lines in which is the common plan of separation (4 ').   3. Device according to claim 1 or 2, characterized in that the surface of the section of the evaporation container (2) located near the common separation plane (4, 4 ') is less than or equal to the surface of said common plan of separation (4, 4 ').   4. Device according to any one of claims 2 or 3,   characterized in that the evaporation (2) and condensation (3) containers   are removably attached to the bent piece (8).   5. Device according to claim 4, characterized in that the   evaporation (2) and condensation (3) containers are identical.   6. Device according to any one of claims 1 to 5,   characterized in that the angle A existing between the arms of the inverted "V" formed by the longitudinal axes of the evaporation (2) and condensation (3) containers is between 30 and 150, and preferably equal to about 90.   7. Device according to any one of claims 1 to 6,   characterized in that the evaporation vessel (2) and / or the vessel of   condensation (3) are in the form of cylindrical tubes. - 13 -   8. Device according to any one of claims 2 to 7,   characterized in that the cylindrical tube or tubes are provided with a means   screwing said one or more tubes into the bent piece (8).   9. Device according to any one of claims 1 to 8,   characterized in that the evaporation vessel (2) is entirely contained in a temperature chamber (9, 9 ') of adjustable temperature, the common separation plane (4, 4') of the evaporation vessels (2) and of condensation (3) being located at and in the plane of one of the walls   (10) of said thermal enclosure (9, 9 ').   10. Device according to claim 9, characterized in that the thermal enclosure (9, 9 ') is insulated on at least its wall portion (10) located near the condensation container (3) by means of at least a layer (11) of thermally insulating material and / or chemically inert.   11. Device according to any one of claims 1 to 10,   characterized in that the material used for the manufacture of the evaporation (2) and / or condensation vessel (s) (3) is a transparent or translucent material allowing a visual control of the levels in said containers (2, 3).