Maxflow Flow Inducement System

Abstract

A mixer apparatus for the treatment of a polymer material to generate the Maxwell effect therein, at a rotor-stator interface in a mixer. The mixer comprises an alternating series of stators and rotors arranged along an elongated driveshaft supported within an elongated housing. The stators and rotors each having at least one helically arranged channel extending from an upstream end of the stator to an end location near the downstream end of that stator, those helically arranged channels preferably are arranged on the surface of the bore extending through the stator. A further generally radially directed channel from the end location of that helically arranged channel to a peripheral surface discharge at the downstream end of that stator is arranged to supply the polymer passing therethrough, to the upstream end of an adjacent rotor having a plurality of helically directed channels arranged on its outer periphery, those channels being inclined radially outwardly and of tapered dimension from an upstream end to a widened downstream end.

Claims

1. A Maxwell effect generating elongational mixer apparatus for the treatment of a polymer material, comprising: an elongated housing having an upstream feed end for receipt of a polymer material to be treated, and a downstream discharge end, for extruded discharge of a treated polymer material; an elongated rotatably driven driveshaft extending through the elongated housing, the driveshaft having a longitudinal extending axis of rotation; an elongated alternating array of stators and rotors arranged on the driveshaft for treating a polymer material within the elongated housing, wherein at least one stator has a bore formed treatment surface arrangement therewithin, the bore formed treatment surface arrangement comprising a polymer flow treatment channel extending from an upstream end thereof to a downstream end thereof, and wherein at least one rotor has an outer peripheral surface thereon, with a polymer flow treatment channel arrangement extending from an upstream end thereof to a downstream end thereof; and wherein each polymer flow treatment channel arrangement in the at least one rotor and the at least one stator extend in a helical configuration from their respective upstream ends to their respective downstream ends, and each polymer flow treatment channel arrangement in the at least one rotor and in the at least one stator are in a radial misalignment with one another with respect to the axis of rotation of the driveshaft.

2. The Maxwell effect generating elongated mixer apparatus as recited in claim 1, wherein a spacer is disposed about the driveshaft, between the at least one stator and its adjacent rotor, to define an adjustable gap therebetween.

3. The Maxwell effect generating elongated mixer apparatus as recited in claim 1, the at least one stator having polymer flow treatment channel therewithin has an upstream side and a downstream side, and the at least one polymer flow treatment channel extending therethrough has an upstream end and a downstream end, wherein in the downstream end of the polymer flow treatment channel is wider in the stator than the upstream end of the channel thereof.

4. The Maxwell effect generating elongated mixer apparatus as recited in claim 1, wherein the at least one stator has a plurality of polymer flow treatment channels therewithin and wherein the at least one rotor has a plurality of polymer flow treatment channels thereacross, the polymer flow treatment channels within the at least one stator being of a different number than the polymer flow treatment channels arrayed across the at least one rotor.

5. The Maxwell effect generating elongated mixer apparatus as recited in claim 1 wherein the at least polymer treatment channel in the at least one rotor is wider at the downstream end thereof than at its upstream end.

6. The Maxwell effect generating elongated mixer apparatus as recited in claim 1 wherein the at least one polymer treatment channel in the at least one stator has an upstream end and a downstream end of different cross-sectional configuration.

7. The Maxwell effect generating elongated mixer apparatus as recited in claim 6 wherein the at least one polymer treatment channel in the at least one stator has a downstream-directed increasing inclination with respect to the longitudinal axis of rotation of the driveshaft.

8. The Maxwell effect generating elongated mixer apparatus as recited in claim 7, wherein the inclination of the at least one polymer treatment channel increases radially outwardly at the downstream end of the stator.

9. A process of elongating the molecular length of a long chain polymer melt or solution through an elongated polymer treating mixer apparatus having an alternating series of rotors and stators mounted on a driveshaft, each of the rotors having an external periphery with an array of channels thereon, each of the stators having an internal bore therein, with an array of channels cut therein, the process comprising steps of: Introducing a polymer into an upstream end of an elongated polymer treating mixer apparatus; driving the polymer into a first channel of a first rotatable rotor in the upstream end of the mixer apparatus, and pushing out that polymer at a downstream end of the first channel, wherein the upstream end of the first channel is shallower than the downstream end of the first channel; and driving the polymer into a first channel of a first stator downstream of and adjacent to the first rotor in the mixer apparatus, and pushing out that polymer out a downstream end of the first channel in the first stator, wherein the upstream end of the first channel in the first stator has a greater radial depth therein and the downstream depth of the first channel in the first stator has a circumferentially wider and shallower radial depth than at its upstream end, to effect radial displacement of the polymer being treated between adjacent stators and rotors as the adjacent stators and rotors are angularly displaced from one another by rotation of the driveshaft rotating the rotors thereattached.

10. The process as recited in claim 9, including: arranging a spacer between the rotatable rotor and the stator downstream and adjacent to the rotatable rotor to create a gap therebetween within the elongated polymer treating mixer apparatus so as to enable accommodation of various polymers treated thereby.

11. The process as recited in claim 9, wherein the array of channels in the rotors are of helical orientation.

12. The process as recited in claim 9, wherein the array of channels in the stators are of helical orientation.

13. The process as recited in claim 9, wherein the channels in the rotors and the channels in the stators are of different numbers from one another.

14. The process as recited in claim 13, wherein the channels in adjacent rotors and stators are occluded from one another during a portion of their respective angular displacement within the mixer apparatus.

15. The process as recited in claim 13, wherein the channels in the rotors and the channels in the stators are sloped with respect to the longitudinal axis of rotation of the driveshaft.

16. An elongated mixer apparatus having an upstream end and a downstream end, the mixer apparatus arranged to enable the treatment of a polymer material to generate a Maxwell molecular-elongation-effect therein, the mixer apparatus comprising an alternating series of stators and rotors arranged along an elongated rotatable driveshaft, the driveshaft having a longitudinal axis of rotation, the driveshaft being rotatable about that longitudinal axis of rotation, and supported within an elongated housing, the stators and rotors each having a particular channel configuration therein, that channel configuration comprising: at least one longitudinally arranged channel extending from an upstream end of the stator to the downstream end of that stator, and at least one longitudinally arranged channel extending from an upstream end of an adjacent rotor to a downstream end of the adjacent rotor, each of these at least one channels having a helical curve thereto and each of these channels being of tapered dimension from an upstream end to a widened downstream end.

17. The mixer apparatus as recited in claim 16, including an adjustable gap between the adjacent stators and rotors.

18. The mixer apparatus as recited in claim 16, including generally straight elongated channels extending through the stator from an upstream end to a downstream end therein, tapering to a wider dimension at its downstream end.

19. The mixer apparatus as recited in claim 16 wherein the at least one channel in the stator and at least one channel in the rotor is inclined radially outwardly from its upstream end to its downstream end.

20. The mixer apparatus as recited in claim 19, wherein the polymer material being treated within the elongated housing by a spaced-apart series of alternating stators and rotors simultaneously follows a saw tooth path and a helical flow path as it is treated from the upstream end to the downstream end of the within the housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The objects and advantages of the present invention will become more apparent when viewed in conjunction with the following drawings, in which:

[0033] FIG. 1 is a side elevational view, in longitudinal section, of a mixing apparatus constructed according to the principles of the present invention;

[0034] FIG. 2 is a perspective view of the elongated mixer showing the alternating rotors and stators mounted upon a shaft on which shaft, the alternating rotor and stator arrangement is shown within the mixer apparatus housing of FIG. 1;

[0035] FIG. 3 is a perspective view of a rotor showing the external peripheral array of angled, tapered channels;

[0036] FIGS. 4A and 4B are an end view of the upstream end and a sectional view of a stator along B-B, showing the tapering, helical aspect of its internal channels;

[0037] FIG. 5 is a longitudinal sectional view, shown here in perspective, presenting the tapered internal channels of the stator shown in FIG. 4;

[0038] FIG. 6 is a perspective view of a full stator, shown only partially in FIG. 5; and

[0039] FIG. 7 is a side elevational view of a further embodiment of the rotor and stator combination represented in FIGS. 1 and 2.

DESCRIPTION OF THE INVENTION IN DETAIL

[0040] Referring now to the drawings in detail, and particularly to FIG. 1, there is shown the present invention for the development of the Maxwell effect on polymer production through an elongated mixer apparatus 20 (such as for example, the trademarked DMX mixer of DMX, Inc.), which mixer apparatus 20 typically comprises an alternating series of stators 22 and rotors 24 configured about a longitudinally extending rotatable driveshaft 26, having and rotatable about a longitudinal axis of rotation L, arranged within an elongated barrel shaped housing 30. In this mixer apparatus 20, a polymer P is introduced in the upstream end 32 thereof typically via a feed screw arrangement 34.

[0041] The flow path of the polymer and the shape characteristics of that flow path are critical to the development of the Maxwell effect (elongation of polymer molecules) with respect to that polymer P. Such flow path originates at the upstream side of the first or upstreammost stator 36, as best represented in isometric view in FIG. 2. It is to be noted that the elongated driveshaft 26 extends longitudinally and rotatively through a central bore 38 longitudinally arranged through each respective stator 22/36, the bore 38 represented in FIGS. 4, 5 and 6.

[0042] Each rotor 24, shown in FIGS. 1 and 2, but represented most clearly in FIG. 3, preferably includes a hub 40 extending from a downstream side 42 thereof. Each rotor 24 and its connected hub 40 have a central bore 44 extending longitudinally therethrough. The hub 40 of the rotor 24 is arranged to mate within the bore 38 of its downstream adjacent stator 22. That downstream adjacent stator 22 has a further downstream adjacent rotor 24 thereadjacent, as is represented in FIGS. 1 and 2. Each rotor 24 has a keyway 46, as shown in FIG. 3. Each rotor 24 is arranged on the downstream side of the each stator 22 and is securely attached via its keyway 46 to mate with a key (not shown for clarity of figures) onto the central, longitudinally extending driveshaft 26 and hence rotates accordingly therewith.

[0043] Each stator 22 has one or more internal, longitudinally extending, helically arranged channels 50 extending along the wall of its bore 38 from a 1.sup.st size/shape channel 1.sup.st opening 60 at the upstream end 52 of the stator 22 to a 2.sup.nd size/shape channel 2.sup.nd opening 62 at the downstream end 54 of the stator 22, best shown in FIG. 4A, the sectional view B-B of FIG. 4A, as shown as FIG. 4B, and FIGS. 5 and 6, the channels 50 being bordered on its innermost side by the rotatable driveshaft 26, as represented in FIG. 7. Each channel 50 within the wall 33 of the bore 36 widens and preferably inclines radially outwardly, downstream, than its entry opening upstream in that channel, (hence discharging flow more radially outwardly closer to the housing) at the downstream end 54 of the stator 22 with respect to the axis L, and also as is evident form the dashed lines in FIG. 4A, and as represented in a sectional view B-B in FIG. 4B, and as may be seen more clearly in the sectional view of FIG. 5. Such channel(s) 50 are also preferably of helical orientation (at preferably between about 15 to about 30 degrees) between its upstream end and its downstream end, as may be envisioned by line H of slight helical direction, shown in FIG. 5. This assures that the total melt flow in the stator 22 is redirected downstream, and also inclined radially outwardly downstream as far as possible within the housing 30 to deliver the polymer melt P into the rotor stator gap G, as represented in FIG. 7, where the Maxwell effect (molecular elongation) will again take place.

[0044] Each rotor 24 has one or more generally longitudinally extending yet helically disposed channels or conduits 66 (at about 15 to about 30 degrees) extending along the outer periphery 68 of that rotor 24, as may be seen by angle Z in FIG. 3. Each channel 66 helically disposed on the periphery of the rotor 24 widens, and in one embodiment, deepens from its upstream end 70 to its downstream end 72 from a shallow, narrow 1.sup.st size and/or shape channel 1.sup.st opening at the upstream end 70 of the rotor's periphery 68 to a 2.sup.nd size and/or shape channel 2.sup.nd discharge which is a deeper and widened opening at the downstream end 72 on the rotor periphery 68, as may be seen in FIG. 3.

[0045] The depth D1 of the channel 66 cut into the periphery 68 of the downstream end 72 of the rotor 24 is preferably radially greater than the depth DZ of the channel 66 cut into the upstream end 62 of the bore 33 of the stator 22, as evident from FIGS. 4, 5 and 7, thus effecting radially inward flow of polymer P, as shown by arrow I in FIG. 7, as that polymer traverses a gap G going between a rotor 24 to an adjacent downstream stator 22. Rotation of the respective rotors 24 relative to the respective adjacent stators 22 represents alternating opening and closing of the polymer flow path while inducing a Maxwell flow, because of the varying shape and non-alignment between their respective longitudinally adjacent channels 66 and 50. The Maxwell flow of a polymer is regenerated by having the center of mass of each stator discharge channel at a greater radial distance from the axis of rotation L. Thus each stator channel 50 delivers the melt to the outermost perimeter of the rotor-stator gap G to regenerate the Maxwell flow driving it radially inwardly for successive flow into its next downstream rotor channel which is inclined radially slightly outwardly.

[0046] Thus, in one preferred embodiment, the channel 50 at the stator discharge end 54 should be wider and deeper (bottom of channel being radially further from the axis of rotation of the driveshaft 26) than the channel 50 is at the stator flow-receiving (upstream) end 62, thereby transmitting the polymer melt further radially outwardly and then radially inwardly into the gap G next to its downstream adjacent rotor 24. Such radial differential in the flow of the mix promotes good development of Maxwell flow by maximizing tangential velocity (because it is travelling further radially outwardly) between longitudinally adjacent (spaced slightly axially apart) stators and rotors. The axial spacing or gap G between adjacent stators 22 and rotors 24 may be adjusted by the addition or removal of O ring members 76 therebetween, as represented in FIG. 7.

[0047] A further preferred embodiment of the channels 50/66 for each of the stators 22 and rotors 24 is that their cross-sectional areas are preferably generally equal to one another, differing in shape in another embodiment, as for example, of rectilinear shape at their downstream ends. A further preferred embodiment of the channels 50/66 for each of the stator 22 and rotor 24 is that there cross-section may be of U shape, or of rectilinear shape in cross-section. The cross-sectional area of axially adjacent channels in the stators 22 and rotors 24 are preferably not to be in complete longitudinal alignment with one another so as to provide the radial displacement to the downstream flow of polymer P between adjacent rotors 24 and stators 22. A 20% to 40% limited overlap between axially adjacent channels 66 and 50 in adjacent rotors 24 and stators 22 is preferred. Such incomplete alignment thus facilitates the Maxwell effect as the polymer transits the gap G between axially adjacent stators 22 and rotors 24, and rotors 24 and stators 22. The repetitive channel occlusion also induces extensional flow which is very important for the two or multiphase systems.

[0048] The rotation of the respective rotors relative to their respective axially adjacent (but not full radial alignment) stators presents alternating opening and closing (periodic occlusion) of the polymer flow path while inducing radial flow both radially outwardly and radially inwardly during the polymer transit through the elongated mixer apparatus, in what might be described as a saw tooth path.

[0049] In yet a further preferred embodiment of the mixer apparatus of the present invention, the number of channels 66 arranged on the peripheral surface of the rotor 24 is different from the number of channels 50 arranged on the internal surface of the bore 38 of the stator 22.

[0050] To further carry out the Maxwell effect on a polymer so as to enable the forced elongation of the polymer molecules, a pinched waist effect induces increased velocity to the polymers driven through the various conduits. However, this is more costly to machine and may not be worth it. The main elongational flow occurs by repetitive occlusion of the channels as the metal of a rotor channel wall partially blocks the entrance into a downstream stator channel in a variable cyclical and periodic manner.

[0051] The cycle of Maxwell effect inducing polymer molecule elongation may thus continue through to the downstream output or die end of the mixer apparatus through an alternating series of (adjustable, by for example the adding or removing one or more O rings 76 arranged therebetween) axially adjacent rotors 24 and stators 22 on the driveshaft 26, each with their respective stator channels of downstream increasing width and rotor downstream channels increasing depth to effect that polymer transformation.

[0052] The Maxwell effect is hence repetitively generated in the gap G between the respective adjacent rotors 24 and stators 22. It is generated due to the visco-elastic behavior of polymer melts and solutions. The shear field can be controlled by adjustably changing the gap size, the tangential velocity of the rotor 24, and the diameter of the rotor 24 and the stator 22. A high shear field is desirable for the exfoliation of nano-particles such as nano-clays. The melt temperature also has a significant effect since the viscosity decreases exponentially with the increase in absolute temperature. The viscosity also decreases with increasing shear rate, again exponentially for the polymer melts which are power law fluids. It should be noted that the polymer melts undergo viscous frictional shear heating. For small-scale equipment this leads to an isothermal melt temperature in the mixer when the internally generated heat is lost to the surroundings of the mixer under steady-state conditions. For large-scale mixers there is not enough mixer surface area and the mixer goes into an adabiatic mode and the melt temperature increases. The melt temperature can be controlled however by reducing the mixer speed. Scale-up development work is required for each application.