US3443796A - Apparatus for processing viscous fluids - Google Patents

Description

May 13, 1969 c. J. SHEARER APPARATUS FOR PROCESSING VISCOUS FLUIDS Sheet of2 Filed Nov. 28,

C. J. SHEARER INVENTOR:

HIS ATTORNEY May 13, 1969 c. J. SHEARER APPARATUS FOR PROCESSING VISCOUS FLUIDS Sheet 2 of2 Filed Nov. 28, 1967 FIG.

c. J.SHEARER BY HIS ATTORNEY APPARATUS FOR PROCESSING VISCOUS FLUIDS Charles J. Shearer, Yonkers, N.Y., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed Nov. 28, 1967, Ser. No. 686,033 Int. Cl. Blf 7/30 U.S. Cl. 259- 7 Claims ABSTRACT OF THE DISCLOSURE Apparatus for processing viscous fluids comprising a cylindrical casing having a rotary member mounted in the casing with its central longitudinal axis offset from the central longitudinal axis of the casing. The rotary member has extensions integral with it and offset from its central longitudinal axis. A plurality of cylindrical rollers are mounted on both the rotary member and the extensions and remain in continuous contact with the inner wall of the casing as they rotate about their own axes.

BACKGROUND OF THE INVENTION Field of the invention.The invention relates to apparatus for processing fluids; more particularly, it relates to apparatus for processing viscous fluids by circulating the fluids within the cylindrical casing having a rotary member with offset extensions and a plurality of rollers mounted on the rotary member and the extensions.

Description of the prior art.Current equipment for the processing of viscous liquid streams (e.g., polymer melts, elastorners, etc.) do not allow for systematic subdivision and redistribution of the flow streamlines. If the fluids are extremely viscous, much power must be expended to achieve a uniform blending of the so-called fluid streamlines of the fluids. Further, the amount of time the fluids remain in the processing equipment (referred to as residence time) is high resulting in much heat loss, building up of fluid particles on the equipment surfaces, etc.

One such device is disclosed in patent application Serial No. 646,324, filed June 15, 1967; however, its mechanical design is fairly complicated as compared to the apparatus disclosed herein.

SUMMARY OF THE INVENTION It is an object of this invention to provide for a systematic subdivision and redistribution of the flow streamlines of viscous fluids thereby leading to a more eflicient process, with concomitant savings in power, reduced residence times, and less degradation of the fluid materials.

It is a further object to provide heat exchanger apparatus for the cooling of melt at the same time allowing close temperature tolerances and preventing channelling.

These and other objects are carried out by circulating a viscous fluid or fluids within an in-line blender, mixer, reactor or similar apparatus having a cylindrical casing and a rotor mounted in the casing having its central longitudinal axis offset from the central longitudinal axis of the casing. The rotor has a plurality of extensions integral therewith, equidistant from the inner wall of the casing and offset from the central longitudinal axis of the rotor. Rollers are mounted on the rotor and the extensions and are so configured to remain in continuous contact with the inner wall of the casing during rotation. Thus, as the rotor is rotated by any known means, fluids flow between the surfaces of the rollers and the inner wall of the casing providing better subdivision and redistribution of the streamlines of the flowing fluids.

Other objects of this invention will become evident from the following detailed description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principles of this invention and the preferred method of applying these principles.

3,443,796 Patented May 13, 1969 BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a vertical sectional view of the apparatus of the invention;

FIGURE 2 is a plan view of the apparatus of FIGURE 1; and

FIGURES 3 and 4 are pictorial representations of the streamline flow patterns taken along the lines 3-3 and 44 of FIGURE 1, respectively.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, FIGURE 1 shows a stationary outer cylindrical casing 11 which may be part of an in-line blending system, a mixer or a reactor as disclosed in patent application Serial No. 646,324. Casing 11 is preferably provided with a outer jacket 12 for selectively heating and cooling the casing 11. Gearing means 13 are fixedly mounted on the inner wall 14 of casing 11 for reasons to be discussed infra. Gearing means 13 extend circumferentially about the entire inner wall 14 of casing 11. A rotary member 15 is mounted in casing 11 and has a first portion 18 having a longitudinal axis 16 offset from the central longitudinal axis 17 of casing 11. A second portion 19 extends from first portion 18 and is coincident with the central longitudinal axis 17 0f casing 11 for rotating rotary member 15. A branch portion 25 extends perpendicular of first portion 18 and has a pair of extension portions extending parallel to first portion 18. The extension portions 21 and 22 are spaced radially of the central longitudinal axis 17 of casing 11 and are preferably equidistant from the inner wall 14 of casing 11. Extensions 21 and 22 are also offset from the longitudinal axis 16 of the first portion 18 of rotary member 15 and are parallel to both the longitudinal axis 16 of portion 18 of member 15 and the central longitudinal axis 17 of casing 11. A pair of rollers 23 and 24 are mounted on extensions 21 and 22 respectively. Rollers 23 and 24 are mounted so as to rotate with extensions 21 and 2.2. The rollers 23 and 24 are so configured so as to remain in continuous contact with the inner wall 14 of casing 11 as they rotate about their own axes. A like roller 29 is rotatably mounted on first portion 18 of rotary member 15 and is substantially greater in cross-sectional diameter than rollers 23 and 24. Roller 29 is so configured to remain in continuous contact with the inner wall 14 of casing 11 as the rotor 15 is rotated.

All of the rollers are cylindrical, preferably hollow and closed at both ends. However, the rollers may be solid, if desired. Roller 29 has its central longitudinal axis coincident with the longitudinal axis 16 of the first extension portion 18 of rotary member 15. Rollers 23 and 24 have their central longitudinal axes coincident with the central longitudinal axes of extension portions 21 and 22, respectively. All of the rollers have gearing means adapted to mesh with the gearing means 13 on the inner wall 14 of casing 11. However, the apparatus could be used without gearing means, if desired. The viscous fluid or fluids, introduced into the apparatus and allowed to flow in the direction of the arrow in FIGURE 1 will flow between the outer walls of rollers 23, 24 and 29 and the inner wall 14 of the casing 11.

FIGURES 3 and 4 show the streamline flow patterns caused by fluids flowing in the apparatus of FIGURE 1. In FIGURE 3, the roller 29 is moving within casing 11 in the direction of arrow 30. At the same time, roller 29 is rotating about its own axis in the direction of arrow 31. The fluids within the casing 11, adjacent the outer wall of roller 29 and the inner wall 11, are being swept in the direction of the arrow 31 as indicated by arrow 32 on the fluid line 33 of FIGURE 3. Due to the movement of the roller 29 over the stationary inner wall 14, the fluid line 33 (close to the wall of 29) changes direction away from the wall as fluid line 34; similarly, the fluid line 36 (close to the wall of 1 4) changes direction away from the wall as fluid line 35. The material between fiuid lines 33 and 34 is separated from material between fluid lines 35 and 36. Thus, there is a systematic subdivision of the flow streamlines. These streamlines will be further subdivided and redistributed as the fluids flow between the surfaces of rollers 23 and 24 and walls '14 and 28 as can be seen in FIGURE 4. Here, rollers 23 and 24 are moving in the direction of arrow 37. The rollers 23 and 24 are rotating in the direction of arrows 38. At the roller 24, the fluid line 39 is swept in the direct-ion of arrow 40 and at roller 23, the fluid line 44 is swept in the direction of arrow 45. The separation of the material between fluid lines is again obtained, and is seen from the position and direction of the other fluid lines 41, 42 and 43, to the left, and 46, 47 and 48, to the right of FIGURE 4. Thus, there is a continual subdivision and redistribution of the fluid flow lines. The preferred embodiment has been shown as an in-line blender in a pipeline system wherein casing 11 is a pipeline; however, the teachings of this invention can be used in the blenders and reactors suggested in patent application Serial No. 646,324. The apparatus can also be used as a heat exchanger in a polypropylene foam extruder. This heat exchanger will give narrow distribution of residence times which prevents undesirable crystallization of the polypropylene foam. The kneading action of the apparatus produces less heat than existing devices and does not break down large molecular structures. In other words, the fluid processing apparatus of the instant invention can be utilized in the processing applications of blending, heat exchanging and reaction. If the clearance between the rollers and its contact surface is kept small, the viscous liquids will be kneaded and complete mixing to a molecular scale will be obtained. The good mixing characteristics of the device are important in the application of heat exchange. There will be no channelling of the flow and large temperature gradients in the liquid should be absent because the streamlines are constantly being subdivided and redistributed. The rotor and outer casing offer surfaces for heat transfer since there are no stagnant liquid layers on the solids Walls. Viscous dissipation is less than in conventional scraped heat exchangers since the velocity gradients between the roller and rotor casing surf-aces are small.

Obviously, any number, size and arrangement of rollers could be used. For example, a row of rollers 23 and 24 could be followed by a roller 29, then another row of rollers 23 and 24, etc. The size, number and location of the rollers in each row would depend on processing requirements. The drive shaft portion 19 could be driven by any known prime mover means, either mechanical or electrical, hydraulic or pneumatic. As discussed previously, the gearing means may be eliminated with the rollers being mounted on rotary member in a manner such that they can rotate about their own axes and remain in continual contact with walls 14 and 28.

The viscous fluid is kneaded as it flows between the rollers and the contact surfaces on the rotary member and the casing. As a heat exchanger, the rollers provide cleaned surfaces on both the rotary member and the casing. Since the liquid flowing through the apparatus is continually being subjected to the action of the rollers, the rotary member, casing and rollers offer surfaces for heat removal. There are no stagnant layers to act as a barrier to the transport of heat and the length of the path of conduction of the heat is short. Viscous dissipation is less here than in conventional scraped heat exchangers. There should be no channelling because of the good mixing characteristics of the apparatus. The apparatus can also find use as a reactor since, for example, in many polymerization reactions the final molecular weight distribution is dependent on local mixing and temperature conditions inside the reactor. Hence, this apparatus would provide a control over the product quality. Since, as a reactor, it may be desirable to achieve a narrow distribution of residence times (that is, the length of time and fluid remains in the reactor), smooth cylindrical rollers can be provided with gearing means as discussed above. Further, the entire outer surfaces of the rollers can be replaced with gear elements, if desired, with mating gearing means on the inner wall 14 of casing 11.

The promising heat exchange and mixing properties of the apparatus strongly suggest that its most useful application is in the reaction operation with viscous melts where large concentration and temperature gradients have to be avoided. The flow patterns of FIGURES 3 and 4 show the flow reversal at the rollers, the fluid material at the Walls of the rotary member and the casing being transported away from the walls. Therefore, a narrow distribution of residence time can be achieved. Such a control over residence-time distribution should be most effective in controlling the molecular-weight distribution in bulkpolymerization reactions.

I claim as my invention:

1. Apparatus for processing viscous fluids comprising:

a hollow cylindrical casing having an inner wall;

a rotary member mounted in said casing and having its longitudinal axis offset from the central longitudinal axis of said casing;

a plurality of extensions integral with the member and spaced radially of the central longitudinal axis of said casing;

said extensions being offset from the central longitudinal axis of said rotary member;

all of said extensions being parallel to both the central longitudinal axis of the rotary member and the central longitudinal axis of said casing;

first cylindrical roller means mounted on said rotary member and having its central longitudinal axis coincident with the central longitudinal axis of said rotary member;

second cylindrical roller means mounted on each of said plurality of extensions and having their central longitudinal axes coincident with the central longitudinal axes of said extensions; and

all of said roller means being so configured so as to revolve about their own axes while remaining in continuous contact with the inner wall of said casing during rotation of the rotary member.

2. The apparatus of claim 1 including a drive shaft portion integral with the rotary member and coincident with the central longitudinal axes of said casing.

3. The apparatus of claim 1 wherein said extensions are equidistant from the inner wall of said casing.

4. The apparatus of claim 3 wherein first gearing means are fixedly mounted on the outer walls of all of said roller means; and

second gearing means are fixedly mounted on the inner wall of said casing adapted to mesh with the first gearing means on the outer wall of all of said roller means.

5. The apparatus of claim '3 wherein the outer walls of said roller means and the inner wall of said casing are smooth.

6. The apparatus of claim 1 including selective heating and cooling means operatively engaging said casing for selectively heating and cooling said casing.

7. The apparatus of claim 1 wherein the apparatus is an in-line blender and the casing is open at both ends so as to allow fluids to pass therethrough.

References Cited UNITED STATES PATENTS 1,607,404- 11/ 1926 Low 2 5 95 3,362,793 1/1968 Massoubre 259-5 X ROBERT W. JENKINS, Primary Examiner.

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