FIELD OF THE INVENTION
The present invention relates to an apparatus used for extraction of materials by liquids under elevated pressures and the process for such extraction.
For the separation of solute from solvent the liquified gas is simply evaporated. The use of sub-critical liquid extraction, hereinafter referred to as SLE, is much simpler than the use of supercritical fluid extraction. It is especially advantageous because it can be performed in one vessel only. Nevertheless, the liquidfied gases yields similar results in the extraction process like supercritical gases and only hardly yields or qualities of the extracts will differ significantly. This is especially true for CO2 . Thus the application of SLE is a cheaper alternative to supercritical gases. SLE can be applied to many practical problems as for leaching of plant materials, soils, polymer etc.
PRIOR ART
U. S. Patent # 4,265,860 Jennings et. al. made use of a normal laboratory scale Soxhlet extractor inside of an autoclave for the extraction of different materials by liquid CO2. This apparatus has been altered by removing the vapor line of the normal Soxhlet and by using windows in the autoclave to control the correct function of the condenser and siphon.
Usually, extraction of the Soxhlet type is a periodical process. In a certain time interval the loaded liquid of the extraction thimble is withdrawn via siphon to the evaporating

by large volume to keep the nearly total liquid content of the extractor.
Therefore, it is an object of the invention to develop a continuous process in which a certain amount of the liquid is continuously evaporated in order to keep the volume of the evaporating part of the autoclave small to use the volume saved in this way for the material to be extracted.
It is another object of the invention that no further high pressure equipment is required.
It is still another object of the invention to increase the yield of the product.
Still another object of the invention is to enable to use the volume of the autoclave much more effectively.
Yet another object of the invention is to allow effective reuse of the solvent and hence minimising the loss of the solvent.
Still another object of the invention is fractionation of materials.
Yet another object is to reduce the cost and to have a cheaper alternative.
According to the present invention there is provided an apparatus for extraction of materials by liquid solvent under elevated pressures comprising:

a high pressure vessel (1) having a top closure member and a bottom closure member, the vessel being divided by a partition member into a upper chamber (3) for the material to be extracted and a lower chamber (2) for the liquid solvent loaded with the extract;
two channels (4,5,) disposed inside the said vessel said first channel (4) being for directing freshly condensed solvent vapour to the bottom of the upper chamber, said first channel configured axially in said vessel with its upper end terminating just below the top closure member and the lower end at a little distance above the partition member, one second channel (5) to conduct said solvent loaded with the extract to the lower chamber and to direct liquid vapours to the condenser (8), said second channel (5) configured parallel to the axis with the upper end at a height lower than the upper end of said first channel and the lower end hydraulically fitting in a corresponding hole in said partition member;
means provided with the said pressure vessel for withdrawing the extract from one vessel and transferring it to another successive vessel enabling the fractionation of the extract; and
a condenser (8) provided at the top end of the pressure vessel (1) for condensing the solvent through any of the channel for reuse of unloaded liquid
a gutter (9) hydraulically connected to condensed solvent into said first channel
a heating source provided in the bottom of the said vessel enabling the liquid solvent to evaporate and cycle.
The subject invention is related to an apparatus to be used for extraction of materials by liquids under elevated pressures

and the method thereof avoiding all the disadvantages of the known state of the art.
The present invention relates to an apparatus for extraction of materials by liquids under elevated pressures and the method thereof overcoming all the drawbacks by developing a continuous process in which a certain amount of the liquid is continuously evaporated in order to keep the volume of the evaporating part of the autoclave small to use the volume saved in this way for the material to be extracted.
An apparatus for the extraction of materials by liquid solvents under elevated pressures comprises an autoclave which is connected with a valve to fill and to discharge the autoclave with the solvent. The autoclave is a cylindrical high pressure vessel with a top closure and a bottom closure.
There is an internal extraction chamber of an apparatus to keep the materials to be extracted with channels in said chamber for the condensed pure liquid and for the loaded liquid and for the vapor.
The apparatus has two separate parts namely an evaporating and a condensing part.
It is the embodiment of the invention that two or more apparatus can be used in a tandem mode enabling the preparation of one of the autoclaves during the extraction time of the other or others.

STATEMENT OF THE INVENTION
According to the present invention there is provided an apparatus for extraction of materials by liquid solvent under elevated pressures comprising:
a high pressure vessel (1) having a top closure member and a bottom closure member, the vessel being divided by a partition member into a upper chamber (3) for the material to be extracted and a lower chamber (2) for the liquid solvent loaded with the extract;
two channels (4,5,) disposed inside the said vessel said first channel (4) being for directing freshly condensed solvent vapour to the bottom of the upper chamber, said first channel configured axially in said vessel with its upper end terminating just below the top closure member and the lower end at a little distance above the partition member, one second channel (5) to conduct said solvent loaded with the extract to the lower chamber and to direct liquid vapours to the condenser (8) , said second channel (5) configured parallel to the axis with the upper end at a height lower than the upper end of said first channel and the lower end hydraulically fitting in a corresponding hole in said partition member;
means provided with the said pressure vessel for withdrawing the extract from one vessel and transferring it to another successive vessel enabling the fractionation of the extract; and
a condenser (8) provided at the top end of the pressure vessel (1) for condensing the solvent through any of the channel for reuse of unloaded liquid
a gutter (9) hydraulically connected to condensed solvent into said first channel

a heating source provided in the bottom of the said vessel enabling the liquid solvent to evaporate and cycle.
According to the present invention there is provided a process for extraction of materials by solvent under elevated pressure in the apparatus as claimed in claim 1 comprisng the steps of charging the upper chamber with the material to be extacted, adding solvent; closing the upper closure member; building up the pressure in the vessel, charging liquid solvent into the upper chamber through the first valve (10) or the second valve (11), the liquid solvent being filled upto a level to submerge the upper end of the second channel, heating the bottom of the lower chamber to evaporate the solvent, withdrawing of extract from lower chamber through valve (7).
According to the other embodiment of the invention wherein the said means for withdrawing the extract is a valve arrangement comprising:
a plurality of valves (7, 10, 11) at least first valve (10)hydraulically connected to the pressure vessel though the top closure member, at least one second valve (11) pneumatically connected to the pressure vessel through the top closure member and at least a third valve (7) hydraulically connected near bottom of the lower chamber.
Still another object of the present invention wherein the said apparatus is a high pressure cylindrical vessel or plurality of cylindrical vessel joined in parallel to each other.

DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to the preferred embodiment, the present invention is illustrated through the following drawings:
Figure 1 illustrates a schematic sketch of an apparatus as one realization of this invention.
Figure 2 illustrates twin apparatus operated under tandem mode.
The autoclave (1) is a cylindrical high pressure vessel in vertical position with a top closure and a bottom closure. This autoclave can be built from suitable steel as for example named by US code 316 or the German code 1.4571.
According to the process involved inside the autoclave is an internal extraction chamber (2) serving as a container for the material to be extracted. This chamber is loaded with the material to be extracted as for example with plant material. The chamber has one channel (4) to direct the freshly condensed liquid to the bottom of the material container. This channel directs the condensed Carbon dioxide in the said container enabling the chamber to be filled with the condensed liquid a little higher than the level to be filled of the plant material thus applying some hydrostatic pressure on the material forcing the liquid through the plant material. In contact with the plant material the liquid CO2 will extract this material. The loaded liquid on top of the plant material flows in the bottom part of the apparatus by a second channel (5).

The bottom is heated by means of heating source provided in the said bottom part which enables the, liquidfied gas to evaporate and the evaporated gas comes back to the chamber. Thus the entire liquified gas is recycled making the process economical and more technically feasible. The extract remains in the lower portion.
In the evaporation part (6) of the apparatus the liquid will be evaporated and the extract of the loaded liquid will remain. The extract is withdrawn to another storage by means of a valve (7) arrangement. A successive withdrawing of the extract enables the fractionation of the extract. The evaporated liquid will flow to a condenser (8) via the same channel (5) as used for the loaded liquid or via a third channel. After condensation the liquid is conducted by a gutter (9) to said first channel to reach the bottom of the plant materials.
Essential for the apparatus is the autoclave, the evaporator, the condenser and channels to separate the streams of pure liquid, of the loaded liquid and of the vapor provided by the internal extraction chamber. It is well possible to operate the apparatus in principle by introducing the solvent as a solid for example dry ice in the same time as the autoclave is loaded with the material to be extracted. However, it will be mostly convenient introducing the solvent via valve (10) or (11) connected with the autoclave. The apparatus can be used if the appropriate amount of solvent is introduced in the autoclave. This can be controlled for example by a balance.
In addition a pressure gauge (12) is provided for controlling the flow of the corbondioxide and thus provides

safety to the apparatus. If the extraction process is finished, the solvent has to be discharged by the valve or eventually solidified by cooling. Hence, it will be advantageous to use the twin apparatus and operating this arrangement in a tandem mode in that event when one apparatus is extracting, the other apparatus is discharging the material to extract and can be recharged with new material. The discharging of the solvent will be done by transferring the gaseous (by valve 10 or liquid by valve 11) solvent to the freshly loaded autoclave by an applied temperature difference, which is causing a corresponding driving pressure difference.
The design can obviously be modified by other arrangements of the channels (4 and 5). Especially it is sometimes e.g. if a cylindrical basket for a plant material is used-advantageous to sue tubes outside the cylinder but connected or welded to the cylinder. Our invention is concerned with continuous extraction. However, a change of the internal extraction chamber to a Soxhlet type arrangement the autoclave itself can of course also be used for periodical extraction.
While particular embodiments of the subject invention have been described, it would be obvious to those skilled in the art that various changes and modifications to the subject invention can be made without departing from the spirit and scope of the invention. It is intended to cover, in the appended claims, all such modifications that are within the scope of the invention.

WE CLAIM;-
1. An apparatus for extraction of materials by liquid solvent under elevated pressures comprising:
a high pressure vessel (1) having a top closure member and a bottom closure member, the vessel being divided by a partition member into a upper chamber (3) for the material to be extracted and a lower chamber (2) for the liquid solvent loaded with the extract;
two channels (4,5,) disposed inside the said vessel said first channel (4) being for directing freshly condensed solvent vapour to the bottom of the upper chamber, said first channel configured axially in said vessel with its upper end terminating just below the top closure member and the lower end at a little distance above the partition member, one second channel (5) to conduct said solvent loaded with the extract to the lower chamber and to direct liquid vapours to the condenser (8), said second channel (5) configured parallel to the axis with the upper end at a height lower than the upper end of said first channel and the lower end hydraulically fitting in a corresponding hole in said partition member;
means provided with the said pressure vessel for withdrawing the extract from one vessel and transferring it to another successive vessel enabling the fractionation of the extract; and
a condenser (8) provided at the top end of the pressure vessel (1) for condensing the solvent through any of the channel for reuse of unloaded liquid
a gutter (9) hydraulically connected to condensed solvent into said first channel
a heating source provided in the bottom of the said vessel enabling the liquid solvent to evaporate and cycle.

2. An apparatus for extraction of materials by liquid solvent
under elevated pressures as claimed in claim 1, wherein the said
means for withdrawing the extract is a valve arrangement
comprising:
a plurality of valves (7, 10, 11) at least first valve (10)hydraulically connected to the pressure vessel though the top closure member, at least one second valve (.11) pneumatically connected to the pressure vessel through the top closure member and at least a third valve (7) hydraulically connected near bottom of the lower chamber.
3. An apparatus for extraction of materials by liquid solvent
under elevated pressures as claimed in claim 1, wherein the said
apparatus is a high pressure cylindrical vessel or plurality of
cylindrical vessel joined in parallel to each other.
4. A process for extraction of materials by solvent under
elevated pressure in the apparatus as claimed in claim 1
comprisng the steps of charging the upper chamber with the
material to be extacted, adding solvent; closing the upper
closure member; building up the pressure in the vessel, charging
liquid solvent into the upper chamber through the first valve
(10) or the second valve (11), the liquid solvent being filled
upto a level to submerge the upper end of the second channel, heating the bottom of the lower chamber to evaporate the solvent, withdrawing of extract from lower chamber through valve (7).
5. A process as claimed in claim 2, wherein the liquid solvent is liquid CO2•

6. A process as claimed in claim 2, wherein the solid solvent is solid CO2.