Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/22—Evaporating by bringing a thin layer of the liquid into contact with a heated surface
  • B01D1/222—In rotating vessels; vessels with movable parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/02—Evaporators with heating coils

Definitions

• the present invention relates to the concentration of active ingredients such as aromatic substances, originating from plant, animal or mineral materials, and in particular an apparatus for evaporating the solvent mixed with these active ingredients after extraction.
• Evaporation of the solvent is usually carried out in evaporators comprising a vertical cylindrical heating enclosure inside which rotates a rotary element provided with blades.
• a rotary element provided with blades.
• the solvent is evaporated and evacuated at the upper end of the enclosure.
• the final product depends entirely on the flow rate of the product introduced into the enclosure and the proper functioning of the rotary element. If this flow rate is too great to allow good evaporation of the solvent, or if the film formed inside the enclosure is too great to allow good evaporation of the solvent, the product scraped by the rotating blades quickly found at the bottom of the enclosure without the solvent being able to be completely evaporated. In these two hypotheses, the residual solvent is too large and the final product does not conform to the desired result. In addition, when the rotary element stops rotating, the product on the wall quickly falls at the bottom of the enclosure and makes unusable the product previously concentrated and already in the lower part.
• the object of the invention is to provide an apparatus for evaporating solvent in which the speed of the rotary element can be adjusted to obtain the best possible result whatever the flow rate.
• Another object of the invention is to provide an apparatus for evaporating the solvent in which the stopping of the rotary element does not lead to an unacceptable increase in the amount of solvent present in the product collected at the outlet of the apparatus.
• the object of the invention is therefore a device for evaporating the solvent of the type comprising a heating chamber into which is introduced in the upper part the product containing the solvent to be evaporated and a rotary element facilitating the evaporation of the solvent and suitable for making lower the product at the same time as there is evaporation of the solvent,
• the rotary element is a heating element comprising a wall whose spacing relative to the wall of the enclosure is constant, and a helical blade integral with the rotary element and constituting a labyrinth around the rotary element filled with the product introduced into the enclosure, the solvent being evaporated thanks to the heating provided by the enclosure and the rotary element as the product descends along the helical thread so that it is practically free of solvent when it is extracted at the bottom of the device.
• the apparatus according to the invention is composed of a conical enclosure 10 in the preferred embodiment, in which there is a rotary element also conical rotating about an axis which is the same as that of the enclosure 10.
• the enclosure 10 comprises an outer casing 14 into which is injected by the inlet nozzle 16, a heating fluid such as water vapor at a vacuum temperature between 50 and 95 °.
• the partly condensed steam is recovered by the outlet nozzle 18 located at the bottom of the enclosure 10.
• the rotary element 12, driven in rotation by a motor 20 comprises a cone 22 whose outer wall has a constant spacing relative to to the inner wall of the enclosure 10.
• the cone 22 is heated internally by a heating fluid such as water vapor as previously at the same temperature as the enclosure, vapor which is introduced through the inlet orifice 22 of a rotary joint 24 in the outer casing 28 of the axial shaft 26 of the rotary element 12. This vapor is therefore introduced into the interior of the cone 22 so as to heat it, and is then recovered by rising inside the axial tube 30 open at its lower end 32 by the outlet orifice 34.
• the cone 22 is provided on its outer wall with a helical thread or a blade in the form of a helix 36, the end of the turns of which is very close to the inner wall of the enclosure 10.
• the distance separating the end of the coils of the enclosure wall can be adjusted by raising or lowering the rotary element 12 along its axis. This distance can thus be precisely adjusted between 0.1 and 0.5 mm.
• the space between the cone 32 and the inner wall of the enclosure 10 thus forms a sort of helical labyrinth whose thickness is equal to the width of the helical thread, ie about 15 mm.
• the mixture of active principle and solvent is introduced through the upper part inlet 40.
• This mixture descends inside the conical enclosure 10 and is entrained in the labyrinth 38 thanks to the rotation of the rotary element 12, rotation which can be between 10 and 30 revolutions / minute.
• the rotation of the rotary element is chosen so that it tends to drag the product in the labyrinth downwards; that is, the rotation is counterclockwise if the thread pitch is on the right and clockwise if the thread pitch is on the left. It should be noted that in continuous mode, the mixture to be treated fills almost completely the labyrinth.
• the rotation of the rotary element 12 has two effects: a first effect is to drive the product located in the labyrinth downwards as we have just seen, but a second effect is to maintain a film of product along the inner wall of the enclosure 10.
• the spacing between two turns may be greater at the top than at the bottom.
• This spacing can for example be 40 mm at the top of the cone while it will only be 15 mm at the bottom of the cone.
• the solvent also evaporates through the film located on the inner wall of the enclosure 10.
• this evaporation only concerns a small percentage of solvent compared to the solvent which evaporates when passing through the product in the labyrinth.
• it is possible to adjust the ratio of these two quantities by raising or lowering the cone along its axis in the enclosure 10 so as to increase or decrease the spacing between the ends of the turns of the helical thread and the inner wall of the enclosure 10. It is thus possible, by increasing the thickness of the film on the wall, to increase the flow rate of entry of the mixture at the inlet 40.
• an increase too high a flow rate will require a maximum thickness of the film and therefore the risk of incomplete evaporation of the solvent.
• He is also at note that the thickness of the film will depend on the viscosity of the mixture to be treated.
• Another parameter is of course the heating temperature of the enclosure 10 and of the cone 22. The higher this temperature, the more the solvent will tend to evaporate quickly.
• a last parameter results from the means used to collect the solvent. Indeed, preferably, the solvent vapors collected in the upper part 46 of the enclosure are transmitted to a condenser 48 operating under vacuum and at low temperature before the solvent is collected at the outlet 50 using an extraction pump. Therefore, it is therefore possible to increase the vacuum level used in the condenser so as to lower the boiling temperature of the solvent. It is therefore clear that the apparatus of the invention has the advantage of being able to regulate the concentration of the final product by playing on several parameters, which was not the case with the apparatuses of the prior art. In addition, during a failure or a rotation stop of the rotary element, the product to be treated remains in the labyrinth and does not come to mix with the product already treated and free of solvent which is at the bottom of the device.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9493354

Family Applications (1)

Country Status (4)

Family Cites Families (5)

• 1996
  • 1996-06-18 FR FR9607825A patent/FR2749769B1/fr not_active Expired - Fee Related
• 1997
  • 1997-06-16 WO PCT/FR1997/001082 patent/WO1997048465A1/fr not_active Ceased
  • 1997-06-16 EP EP97929360A patent/EP0906143A1/de not_active Withdrawn
  • 1997-06-16 AU AU33487/97A patent/AU3348797A/en not_active Abandoned

Non-Patent Citations (1)

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