EP0267932A1 - Mixing device - Google Patents

Mixing device

Info

Publication number
EP0267932A1
EP0267932A1 EP87903132A EP87903132A EP0267932A1 EP 0267932 A1 EP0267932 A1 EP 0267932A1 EP 87903132 A EP87903132 A EP 87903132A EP 87903132 A EP87903132 A EP 87903132A EP 0267932 A1 EP0267932 A1 EP 0267932A1
Authority
EP
European Patent Office
Prior art keywords
mixing device
stationary
mixing
extruder
melt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP87903132A
Other languages
German (de)
French (fr)
Inventor
Bernard Alzner
Desider G. Csongor
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0267932A1 publication Critical patent/EP0267932A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/05—Stirrers
    • B01F27/07—Stirrers characterised by their mounting on the shaft
    • B01F27/074—Stirrers characterised by their mounting on the shaft having two or more mixing elements being concentrically mounted on the same shaft
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/21—Mixers with rotary stirring devices in fixed receptacles; Kneaders characterised by their rotating shafts
    • B01F27/2123—Shafts with both stirring means and feeding or discharging means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/27—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices
    • B01F27/272—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices with means for moving the materials to be mixed axially between the surfaces of the rotor and the stator, e.g. the stator rotor system formed by conical or cylindrical surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F2025/91—Direction of flow or arrangement of feed and discharge openings
    • B01F2025/912—Radial flow

Definitions

  • the present invention relates to a melt mixing device.
  • the most common use is in the area of polymers where mixing of dissimilar materials and additives such as fillers, pigments, and plasticizers is a frequent procedure. Other applications may be in the ceramics and food processing industries.
  • Specific mixing requirements are as varied as the materials to be mixed in terms of specific dispersion and distribution needs. While many effective mixing devices are known in the trade, none provide effective heat exchange capabilities so important in most processes of polymers.
  • the combined application of mixing action and cooling synergistically enhances the efficiency of both. Good, efficient mixing was shown analytically by R.S. Spender and R.M. Wiley, and more recently by L. Erwin to be dependent on frequent interruption and reorientation of melt flow between points of high shear.
  • Intrinsic to the present invention is a 180 degree reversal in flow direction at the end of each cylindrical blade, and the application of shear perpendicular to the main flow direction not available in any of the devices known in the art. Shear and mixing in general is accompanied by the generation of heat which leads to difficulties with heat sensitive materials and processes. This problem is readily controllable in subject invention apparatus while none of the prior art devices provide this feature. Summary of the Invention
  • the present invention maximizes mixing capabilities by virtue of the fact that melt flow is reversed 180 degrees at the end of each cylindrical blade while simultaneously subjecting the melt of shearing forces transverse to the direction of the main stream. This in itself meets the condition for efficient mixing as defined by earlier cited theoreticians on the subject of mixing. Mixing capabilities of the present invention may be further enhanced by varying the clearance in the annular space between cylindrical blades, by interrupted flow channels or ridges, intermeshing pins, blades and similar obstructions variously employed in the art for the explicit purpose of mixing. A most effective mixer configuration is described in U.S. 4,447,156 which combined with the present invention results in a highly effective and efficient mixing and cooling apparatus.
  • the most significant feature of the present invention is in the synergistic enhancement of mixing and thermal control which arises from the fact that virtually every particle within the melt is exposed to the temperature controlled surfaces of the stationary cylinders of subject mixer. This is particularly important with heat sensitive materials and processes.
  • the mixing apparatus of this invention may be connected to the exit end of the plasticating extruder with the rotating element attached to the extruder tip and the stationary component to the barrel or die or both. Alternatively, the mixer may be operated as a separate unit having its own motor drive. Description of the Preferred Embodiment
  • Fig. 1 illustrates an embodiment of subject invention apparatus 1 constructed in accordance to subject disclosure. It is connected to the end of an extruder 2 in which the screw performs the essential function of melting, plasticating and pumping the melt to the mixer.
  • the revolving component of the mixer comprised of a multitude of concentrically positioned cylindrical, i.e., bell shaped, blades, is connected to the tip 5 of screw 3.
  • This rotor revolves within a tapered cylinder 6 cored to allow circulating a cooling fluid -through it for precise temperature control of the mixing process 7.
  • the stationary body of concentric cylinders 8 intermeshes with the cylindrical blades 4 of the rotor to form a nestled assembly of cylindrical blades with alternating stationary and revolving elements.
  • the melt is thus forced to flow from the outer cylinder toward the center of the stationary body through the annular space formed by the intermeshing blades being, thereby, subjected to radial shear and axial flow shear simultaneously.
  • Interrupted ridges 10, pins 11, blocks, grooves etc. provide enhanced mixing action as required.
  • Points of high shear may also be incorporated by reducing the clearance in short segments of the annular space formed by the cylindrical blades.
  • Cutting blades 13 revolving within radial channels with small clearance further enhance the mixing action.
  • Melt conveying, i.e., pumping, flights may alternate with mixing elements to provide the desired balance of mixing and pumping.
  • the stationary mixing element 8 is cored 12 to provide close temperature control at the points of high shear, i.e., at points of heat generation. What is claimed is:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)

Abstract

L'appareil décrit est utilisé pour mélanger des fluides visqueux tels que des polymères naturels et synthétiques ainsi que leurs additifs dans des conditions de température contrôlées. A cet effet, le dispositif de mélange comprend une multitude de cylindres en forme de cloche emboîtés de manière co-radiale (4, 8) avec leurs ailettes alternativement stationnaires et rotatives. Le corps rotatif des cylindres est fixé à une source d'énergie extérieure telle qu'une vis (3) entraînée par un moteur d'une extrudeuse de plastification. Le corps stationnaire de cylindres est fixé aux parois de l'enceinte de l'appareil de plastification, c'est-à-dire le cylindre d'extrudeuse, soit faisant partie intégrante de la filière soit pris en sandwich entre la filière et le cylindre d'extrudeuse. Le bloc stationnaire est noyauté pour former un passage (7) pour un fluide de chauffage ou de refroidissement procurant à l'appareil des capacités d'échange thermique efficaces. Les ailettes cylindriques coaxiales peuvent être pourvues d'un nombre quelconque de broches, blocs, lames, canaux (13), etc. destinés à améliorer les caractéristiques de mélange du dispositif par tranchage, cisaillement et mélange du fluide visqueux. Le fluide mixé peut sortir du dispositif de mélange par un canal circulaire (9) ménagé dans la partie centrale du composant stationnaire du mélangeur. Dans le dispositif, le sens d'écoulement est inversé de 180 degrés à l'extrémité de chaque ailette pendant que le fluide est soumis à des actions de cisaillement transversal et chaque côté du courant principal est exposé alternativement aux ailettes cylindriques stationnaires contrôlées en température. L'application combinée et simultanée de cisaillement, mélange et refroidissement permet d'obtenir un échangeur de chaleur et un mélangeur de coulée très efficaces.The disclosed apparatus is used to mix viscous fluids such as natural and synthetic polymers and their additives under controlled temperature conditions. To this end, the mixing device comprises a multitude of co-radially nested bell-shaped cylinders (4, 8) with their alternately stationary and rotating fins. The rotating body of the cylinders is attached to an external power source such as a screw (3) driven by a motor of a plasticizing extruder. The stationary body of cylinders is fixed to the walls of the enclosure of the plasticizer, i.e. the extruder cylinder, either forming an integral part of the die or sandwiched between the die and the cylinder extruder. The stationary block is cored to form a passage (7) for a heating or cooling fluid providing the device with effective heat exchange capacities. The coaxial cylindrical fins can be provided with any number of pins, blocks, blades, channels (13), etc. intended to improve the mixing characteristics of the device by slicing, shearing and mixing the viscous fluid. The mixed fluid can leave the mixing device through a circular channel (9) provided in the central part of the stationary component of the mixer. In the device, the direction of flow is reversed 180 degrees at the end of each fin while the fluid is subjected to transverse shear actions and each side of the main stream is alternately exposed to the stationary temperature-controlled cylindrical fins. The combined and simultaneous application of shearing, mixing and cooling results in a highly efficient heat exchanger and melt mixer.

Description

MIXING DEVICE
Background of the Invention
The present invention relates to a melt mixing device. The most common use is in the area of polymers where mixing of dissimilar materials and additives such as fillers, pigments, and plasticizers is a frequent procedure. Other applications may be in the ceramics and food processing industries. Specific mixing requirements are as varied as the materials to be mixed in terms of specific dispersion and distribution needs. While many effective mixing devices are known in the trade, none provide effective heat exchange capabilities so important in most processes of polymers. The combined application of mixing action and cooling synergistically enhances the efficiency of both. Good, efficient mixing was shown analytically by R.S. Spender and R.M. Wiley, and more recently by L. Erwin to be dependent on frequent interruption and reorientation of melt flow between points of high shear. Intrinsic to the present invention is a 180 degree reversal in flow direction at the end of each cylindrical blade, and the application of shear perpendicular to the main flow direction not available in any of the devices known in the art. Shear and mixing in general is accompanied by the generation of heat which leads to difficulties with heat sensitive materials and processes. This problem is readily controllable in subject invention apparatus while none of the prior art devices provide this feature. Summary of the Invention
The present invention maximizes mixing capabilities by virtue of the fact that melt flow is reversed 180 degrees at the end of each cylindrical blade while simultaneously subjecting the melt of shearing forces transverse to the direction of the main stream. This in itself meets the condition for efficient mixing as defined by earlier cited theoreticians on the subject of mixing. Mixing capabilities of the present invention may be further enhanced by varying the clearance in the annular space between cylindrical blades, by interrupted flow channels or ridges, intermeshing pins, blades and similar obstructions variously employed in the art for the explicit purpose of mixing. A most effective mixer configuration is described in U.S. 4,447,156 which combined with the present invention results in a highly effective and efficient mixing and cooling apparatus.
The most significant feature of the present invention is in the synergistic enhancement of mixing and thermal control which arises from the fact that virtually every particle within the melt is exposed to the temperature controlled surfaces of the stationary cylinders of subject mixer. This is particularly important with heat sensitive materials and processes. The mixing apparatus of this invention may be connected to the exit end of the plasticating extruder with the rotating element attached to the extruder tip and the stationary component to the barrel or die or both. Alternatively, the mixer may be operated as a separate unit having its own motor drive. Description of the Preferred Embodiment
Fig. 1 illustrates an embodiment of subject invention apparatus 1 constructed in accordance to subject disclosure. It is connected to the end of an extruder 2 in which the screw performs the essential function of melting, plasticating and pumping the melt to the mixer. The revolving component of the mixer, comprised of a multitude of concentrically positioned cylindrical, i.e., bell shaped, blades, is connected to the tip 5 of screw 3. This rotor revolves within a tapered cylinder 6 cored to allow circulating a cooling fluid -through it for precise temperature control of the mixing process 7. The stationary body of concentric cylinders 8 intermeshes with the cylindrical blades 4 of the rotor to form a nestled assembly of cylindrical blades with alternating stationary and revolving elements. The melt is thus forced to flow from the outer cylinder toward the center of the stationary body through the annular space formed by the intermeshing blades being, thereby, subjected to radial shear and axial flow shear simultaneously. Interrupted ridges 10, pins 11, blocks, grooves etc. provide enhanced mixing action as required. Points of high shear may also be incorporated by reducing the clearance in short segments of the annular space formed by the cylindrical blades. Cutting blades 13 revolving within radial channels with small clearance further enhance the mixing action. Melt conveying, i.e., pumping, flights may alternate with mixing elements to provide the desired balance of mixing and pumping. The stationary mixing element 8 is cored 12 to provide close temperature control at the points of high shear, i.e., at points of heat generation. What is claimed is:

Claims

1. A mixing device comprised of a stationary and rotating body of concentric cylinders.
2. A mixing device as claimed in Claim 1 wherein both rotating and stationary components comprise a multitude of concentric cylinders.
3. A mixing device as claimed in Claim 1 wherein the rotating and stationary body comprise a nestled assembly of intermeshing cylindrical blades.
4. A mixing device as claimed in Claim 1 wherein rotating component is driven by an external power source or by a screw of a plasticating ext uder.
5. A mixing device as claimed in Claim 1 the stationary body is attached to the die, extruder barrel, or both of a plasticating extruder.
6. A mixing device as claimed in Claim 1 wherein a nestled assembly of cylinders in which rotating and stationary cylindrical blades alternate.
7. A mixing device as claimed in Claim 1 wherein an assembly of concentric, bell shaped cylinders in which the melt is caused to reverse 180 degrees in its flow direction at the end of each cylinder blade as it flows toward the exit 9 channel at the center of the mixer.
8. A mixing device as claimed in Claim 1 wherein the melt is thoroughly mixed and cooled simultaneously.
9. A mixing device as claimed in Claim 1 wherein the mixer barrel as well as the stationary mixer body is cored to provide passage for a cooling media.
10. A mixing device as claimed in Claim 1 wherein mixing elements are embedded deep in the mixed fluid and provided with cooling means for close temperature control of the mixing process.
11. A mixing device as claimed in Claim 1 wherein a melt mixer heat exchanger is operated coaxially with a plasticating extruder.
12. A mixing device as claimed in Claim 1 wherein a melt mixer heat exchanger is operated coaxially with a plasticating extruder.
13. A mixing device as claimed iii Claim 1 wherein a melt mixer heat exchanger is independently driven in tandem with a melt extruder.
EP87903132A 1986-04-25 1987-04-16 Mixing device Withdrawn EP0267932A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US85616386A 1986-04-25 1986-04-25
US856163 1986-04-25

Publications (1)

Publication Number Publication Date
EP0267932A1 true EP0267932A1 (en) 1988-05-25

Family

ID=25322974

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87903132A Withdrawn EP0267932A1 (en) 1986-04-25 1987-04-16 Mixing device

Country Status (2)

Country Link
EP (1) EP0267932A1 (en)
WO (1) WO1987006496A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5813758A (en) * 1993-12-10 1998-09-29 Ahlstrom Machinery Inc. Concentric ring fluidizing mixer
DE19738128A1 (en) * 1997-09-01 1999-03-11 Rolf Dipl Ing Schnause Method and device for centrifuging viscous fluids, in particular viscous plastic melts
DE102004061042A1 (en) * 2004-12-18 2006-06-29 Esa Patentverwertungsagentur Sachsen-Anhalt Gmbh Method and device for separating polymer mixtures

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1670593A (en) * 1923-12-03 1928-05-22 Barrett Co Mixing machine and process
DE582102C (en) * 1930-04-12 1933-08-08 I G Farbenindustrie Akt Ges Device for mixing liquids with one another or of liquids with solid bodies and for producing emulsions
US2555899A (en) * 1949-08-19 1951-06-05 Pernthaler Fritz Centrifugal variety apparatus for mixing and reacting liquid materials
GB891152A (en) * 1957-11-21 1962-03-14 Peter Willems A method and apparatus for continuously changing the structure of substances or mixtures of such substances
US3000618A (en) * 1958-09-03 1961-09-19 Et Oakes Corp Continuous mixer
US3253300A (en) * 1964-01-31 1966-05-31 Black Clawson Co Mixing valve
CH485479A (en) * 1968-09-05 1970-02-15 Supraton Bruchmann & Zucker Kg Device for the production of dispersions or solutions
US3910346A (en) * 1974-01-23 1975-10-07 Braak Bv Geb Mixer

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8706496A1 *

Also Published As

Publication number Publication date
WO1987006496A1 (en) 1987-11-05

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