Solids mixing apparatus

Abstract

 @ A machine for mixing solids in portable containers has a standard in which a mixing bar extending through the container may be rotably supported. A drive shaft extends from a drive station. The drive shaft rotates about a horizontal axis. The standard has an axis which intersects the logitudinal axis of the container at an angle other than 90 degrees, preferably 60 degrees, such that the longitudinal axis of the container is tilted at an angle, preferably 30 degrees, to the vertical when the container and standard are clamped to the drive shaft with the axis of the standard horizontal and co-indicent with the drive shaft axis. A clamp mechanism in cooperative with the container, standard and drive shaft clamps the container so that its longitudinal axis is tilted to the vertical while it rotates about the horizontal axis of the drive shaft. The continuous tilt while revolving causes the container to execute a symmetric wobble motion for rapid and complete mixing (blending) of particulate material, whether fine or coarse, in the container.

Description

[0001] The present invention relates to solids mixing apparatus for mixing or blending solid particulate material and particularly mixing machines in which solids carried in portable containers may be mixed while in their containers.

[0002] The invention is especially suitable for mixing powders and other solid particulate material, both coarse and fine. The containers may be shipping containers or process containers in which the solids are transported. Liquids may also be mixed with the particulate material in mixing machines in accordance with the invention and vacuum drying with or without heat transfer may be applied.

[0003] Mixing or blending of solids in portable containers has been carried out in containerized solid mixing machines such as described in U.S. Patent No. 4,146,335 issued March 27, 1979. In the course of mixing in such machines, the container is revolved about an axis which is tilted from the horizontal. The axis of rotation is then normal to the longitudinal axis of the container. In some cases such orientation results in compaction of solids in one of the corners of the container. When the axis of rotation makes an angle different from 90 degrees with the longitudinal axis of the container while the axis of rotation is horizontal, a continuous tilt of the containers longitudinal axis with the vertical while the container revolves is maintained. A symmetric wobble motion then results which prevents the development of any stagnation regions in the course of mixing in which solids may be compacted.

[0004] Although various arrangements have been proposed for holding containers'so that they may be revolved, the problem remains of providing a portable container which can be conveniently handled and conveyed between process operations as well as in and as part of a solids mixing machine. Reference may be had to the above mentioned Patent No. 4,146,335 and to Patents Nos. 2,868,519; 3,374,584; and 4,050,580 for various arrangements in which the material being mixed is being tilted while revolved for mixing.

[0005] Accordingly, it is an object of the present invention to provide an improved solids mixing machine.

[0006] It is a further object of the present invention to provide an improved solids mixing machine in which the materials being mixed execute a symmetric wobble motion which prevents the formation of stagnation regions in the container in which the materials are disposed.

[0007] It is a still further object of the present invention to provide improved solids mixing apparatus in which the container may be tilted at an angle other than normal to a horizontal axis about which the container is revolved.

[0008] It is a still further object of the present invention to provide an improved solids mixing machine in which the longitudinal axis of a container for the material being mixed is inclined to the vertical while its axis of rotation is horizontal and through which a process or mixing bar, also rotatable about the horizontal axis, extends.

[0009] It is a still further object of the present invention to provide an improved solids mixing machine which utilizes a container which accepts a mixing bar through the center thereof and is revolved with a tilt about an axis which promotes a motion that causes the particulate material to slide in opposite directions to enable mixing to occur rapidly and thoroughly without the buildup of unmixed material in the corners or other areas of the container.

[0010] Briefly described, solids mixing apparatus in accordance with the invention has a drive station in which a drive shaft is fixed to rotate about a horizontal axis. A portable container in which the solids to be mixed are carried has top, bottom and side walls. The container usually has a cylindrical cross-section, but may also have a rectilinear cross-section. The longitudinal axis of the container extends in a direction between the top and bottom of the container. Clamp means attach the container to the drive shaft for rotation about the horizontal axis. The clamp means incorporates a standard which is connected to the container's side wall and has an axis which intersects the longitudinal axis at an angle less than 90 degrees (such that the longitudinal axis of the container is tilted at an angle other than normal to the horizontal axis while the container revolves about that horizontal axis. The particulate material in the container executes a symmetric wobble motion which is approximately an "X" when the horizontal axis intersects the longitudinal axis midway between the top and bottom of the container. The sliding and spilling action of the material causes rapid thorough mixing (blending) without segregation of any species of material as in the corners of the container. A "Y" motion may be obtained when the horizontal axis intersects the longitudinal axis of rotation at the point offset from the midpoint between the top and bottom of the container.

[0011] The foregoing and other objects, features and advantages of the invention, as well as presently preferred embodiments thereof, will become more apparent from a reading of the following description in connection with the accompanying drawings in which:

FIG. 1 is a view in elevation of a solids mixing machine which embodies the invention;

FIG. 2 is a plan view of the machine shown in FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3;

FIG. 5 is an elevation of a solids mixing machine in accordance with another embodiment of the invention; and

FIG. 6 is an end view of the machine shown in FIG. 5 taken from the left side thereof as viewed in FIG. 5.

[0012] Referring first to FIGs. 1 through 4, there is shown a mixing machine 10 which is adapted to mix particulate material in a container l2. The container 12 is portable and may be a cylindrical drum, for example about 18 inches tall and 12 inches in diameter. The container may be carried manually by handles 14. The container is closed at its bottom and 16 and sealed by a cover at its top end 18. The longitudinal axis 20 of the cylinder is perpendicular to its top and bottom 16 and 18 and extends therebetween.

[0013] The container is revolved by a system of coaxial drive shafts 22 and 24. These drive shafts are driven from a drive station 26 which contains motors, a speed reducer and bearings which provide the necessary support for the drive shaft system. The outer drive shaft 22 which revolves the container is a generally cylindrical bell housing with a collar 28. The collar has alignment pins 30 therein which project horizontally from the end of the collar 28 which faces the container 12. The drive shaft has a horizontal axis 32 and is fixed to rotate about that axis. The rotation may either be clockwise or counter-clockwise.

[0014] In order to attach the container to the drive shaft 12 so that the longitudinal axis 20 of the container is tilted at a certain angle, preferably 60 degrees to the horizontal axis 32 and therefore 30 degrees to the vertical, clamping means 34 is provided. This clamping means is a standard 36 having two sections 36a and 36b which extend from the side wall of the container 12 at diametrically opposite locations. The standards are rectangular in cross sections and have a central axis which is coincident with the horizontal axis 32 when the container is mounted on the drive shaft 22 the end of the standard section 36a is closed by a plate 38. The plate 38 has holes 40 for receiving the alignment pins 30. Stiffener plates 42, connecting the side wall of the container 12 to the top of the standard section 36a, provide additional support. The other standard 36b is also closed by a rectangular plate 44 at its outer end.

[0015] Plates 46 and 48, which are curved along an edge in order to conform to the cylindrical shape of the side wall of the container 12,-are attached to the standard. These plates 46 and 48 are in a horizontal plane coincident with the horizontal axis 32. The plates 46 and 48 have holes 50 and 52. Attached to the drive shaft 22 are plates 54 and 56 on which are mounted toggle linkages including hook links 58 and 60 which are pivotly mounted on actuator links 62 and 64. When the hook links 58 and 60 are inserted into the holes 50 and 52 and the links 62 and 64 brought down, the standards and the containers are pulled towards the shaft 22 and locked thereon. Pins 66 and 68 extend through posts on the plate 54 and 56 so as to hold the lever links 62 and 64 down when the container is in place.

[0016] The container accepts a process or mixing bar 80, best shown in FIG. 3. Mixing impellers 80 and 84 extend radially from the mixer bar 80. The mixer bar has a shaft extension 86 which is keyed at 88 to one- half of a coupling 90. The other half of the coupling 92 is attached to the center shaft 24 of the drive shaft system. The mixer bar is a cylindrical rod which is journaled in bearings 94 and 96 which are attached to the end plates 38 and 44 of the standard sections 36a and 36b. These bearings 94 and 96 may be sleeve bearings, as shown, or ball bearings. A seal assembly 100 is attached inside the standard section 36a to the end plate 38a. A similar seal assembly 102 is attached to the end plate 44 of the other standard section 36b. The seal assembly 100 is typical and includes a collar 104. The end of the collar inside the container 12 has a V seal 106. Another seal 108 surrounds the mixer shaft in the end plate 38.

[0017] The container is still between 60 to 70 percent full as measured along its central longitudinal axis 20. When the container is placed on the shaft and the standard 36 aligned, the coupling section 90 and 92 fit together. The container is then revolved about the horizontal axis. The horizontal axis 32 and the longitudinal axis 20 of the container intersect at a point approximately midway between the top and the bottom 18 and 16 of the container. As it revolves, the container executes a motion which traces an "X" symmetric about the intersection of the axes 20 and 32. If desired the horizontal axis may be offset somewhat, for example 10 to 20 percent of the diameter of the container 12, either above or below the mid-point of the longitudinal axis 20. Then, the symmetric wobble motion of the container has a translational component and the motion traces a "Y". Due to this motion, "X" or "Y", there is a sliding and spilling action internally of the container of the material therein. This causes a rapid blending or mixing of the particles whether fine or coarse. The speed of rotation may be up to the speed at which centrifuging of the particulate material therein occurs. The symmetric wobble motion back and forth prevents any stagnation regions from being set within the container 12. Accordingly, thorough blending or mixing occurs.

[0018] Referring next to FIGS. 5 and 6, the dashed lines 120 indicate the outline of an enclosure for the drive station of the solids mixing machine 122. The drive shaft 126 extends from the drive station and rotates about a fixed, horizontal axis. A bearing housing 128 supports in a cantilever manner, the drive shaft 126 and a speed reducer assembly 130. A structure of I-beams 132, including an angled bracing beam 134 supports the bearing housing. A rod and turnbuckle 136 braces the gear reducer 130.

[0019] A low speed motor 138 and a high speed motor 140 are attached to the reducer 130. Belt and pulley drives 142 and 144 transfer torque from the motors 138 and 140 to the reducer. The reducer is held from rotating by a rod and turnbuckle 136. Shafts in the bearing housing 128 transfer the power from the low speed motor to the outer one of two coaxial shafts of the drive shaft system 126. The high speed motor 140 drives the inner shaft of the shaft assembly 126. The arrangement of shafts in the drive shaft assembly 126 may be similar to that shown in FIG. 3.

[0020] The container 150 of the mixing machine 122 may be much larger than the container 12 of the mixing machine 10 shown in FIGS. 1 through 4. The container 150 may be cylindrical or rectilinear in cross-sectional shape and has top and bottom walls 152 and 154 and side walls 156. Standards 160 and 162 of a design similar to the standards 36a and 36b are integrally attached to the container side walls 156. These standards may be on diametrically opposite locations on the walls 156. The central axis 164 through the standards 160 and 162 extends through the center of the container 156 and intersects the longitudinal axis 166 thereof. A mixing bar similar to the bar 80 may be journaled in the standards 160 and 162. A coupling 168 at the end of the standard 160 is adapted to engage a coupling on the inner drive shaft of the drive shaft assembly 126 when the container is tilted and secured in clamp engagement to the shaft assembly 126.

[0021] In order to secure the container so that it may revolve with its axis tilted, preferably at 30° to the vertical, clamp means are provided in the form of a column 170 having top and bottom flanges 172 and 174. The bottom flange 174 is tilted at 176 to the column 170. The column itself is inclined at the desired angle of tilt to the horizontal axis of the drive shaft assembly 126. This angle of tilt is preferably 30° to the vertical and 60° to the horizontal axis of the drive shaft assembly 126. A post and brace 178 and 180 provide support for the container 150. A link 182 is attached to a crank 184 by a gear mechanism mounted in the shaft assembly 126. When the crank is rotated the link 180 is drawn in thereby tilting the lower flange 174 to the position shown in dash lines.

[0022] The upper flange 172 is reciprocally mounted on the column 170. Further rotation of the crank transfers motion through a gear and rack assembly (not shown) to pull the top flange 170 down to the position shown by the dash lines, after the container is tilted by the pivoting of the lower flange 174. The upper flange then clamps the container in place with its axis at the desired angle to the vertical. The intersection of the drive shaft axis and the longitudinal axis 166 may be at the midpoint between the top and the bottom 152 and 154 of the container so that "X" motion symmetric about the intersection may result. Such symmetric motion may be more preferable to "Y" motion, inasmuch as additional torque and bearing support will be needed for the translational component of force exerted on the drive shaft and bearing housing 128 by the large container 150 loaded with material to be mixed, over what is needed for "X" motion.

[0023] From the foregoing description it will be apparent that it has been provided an improved solids mixing apparatus which is adapted to have a desirable motion for uniform and rapid mixing of particular solid materials of various density and size. The particular angle of tilt with respect to the vertical and the horizontal axis of rotation will depend upon the density, particle size, whether liquids are to be blended with the solids and other environmental conditions. It would be noted that liquid may be added through the mixing bar (80 FIG. 3) if desired. Vacuum may be applied via the mixing bar and a heat transfer jacket may be used. Other variations and modifications of the herein described apparatus, within the scope of the invention, will undoubtedly suggest themselves to those skilled in the art. Accordingly, the foregoing description should be taken as illustrative and not in a limiting sense.

Claims

1. Solids mixing apparatus which comprises a drive station having a drive shaft fixed to rotate about a horizontal axis, a portable container in which the solids to be mixed are carried, said container having a side wall, a top and bottom, the longitudinal axis of said container extending in a direction between the top and bottom of said container, clamp means for attaching said container to said shaft for rotation about said horizontal axis, said clamp means having a standard connected to said container side wall, said standard having an axis which intersects said longitudinal axis at an angle less than 90° such that said longitudinal axis of said container is tilted at a certain angle of less than 90⁰ to said horizontal axis while said container revolves about said horizontal axis.

2. The apparatus according to claim 1 further comprises mixing bar means having an axis, and said standard having means for rotatably mounting said mixing for rotation about the axis of said standard.

3. The apparatus according to claim 2 wherein said drive shaft has coaxial shafts, one of said coaxial shafts and said mixing bar means having couplings attached to each other for rotation of said mixing bar means about said horizontal axis when said clamp means attaches said container to said drive shaft.

4. The apparatus according to claim 3 wherein said standard bar sections attached to said container side wall on diametrically opposite sides thereof, said mounting means comprising bearings in each of said sections rotatably mounting said bar near opposite ends thereof.

5. The apparatus according to claim 4 further comprising seal means in each of said sections extending through said side wall of said container to seal said standard from the interior of said container.

6. The apparatus according to claim 1 wherein said clamp means comprises a plate connected to said standard and disposed in a plane containing the axis of said standard which is horizontal when said container is attached to said drive shaft, cooperative coupling means in said plate and drive shaft for clamping said standard and drive shaft together.

7. The apparatus according to claim 6 wherein said plate has a hole therein, a toggle linkage attached to said drive shaft including a hook engageable with said plate in said hole.

8. The apparatus according to claim 7 wherein said plate has a pair of said holes on opposite sides thereof and a pair of said toggle linkages each attached to said drive shaft on diametrically opposite sides thereof.

9. The apparatus according to claim 1 wherein said clamping mechanism comprises a frame having a column, a top flange and a bottom flange, said column having a longitudinal axis extending in a direction between said top and bottom flanges, said column being connected intermediate the ends thereof to said drive shaft with the longitudinal axis of said column at said certain angle to said horizontal axis, said bottom flange being pivotally mounted on said column for receiving said container when in a horizontal plane and tilting said container to bring its longitudinal axis to said certain angle, said top flange being mounted on said column for reciprocating movement along the longitudinal axis thereof of said column and means for tilting said bottom flange and reciprocating said top flange to clamp said container in said frame with the longitudinal axis of said container tilted at said certain angle while said container revolves with said frame about said horizontal axis.

10. The apparatus according to claims 1 or 9 wherein said horizontal axis of said drive shaft intersects the longitudinal axis of said container where said container clamped to said drive shaft at a point about midway between said top and bottom thereof such that said container executes a wobble motion symmetric about the intersection of said longitudinal container axis and said horizontal axis.

11. The apparatus according to claims 1 or 9 wherein said horizontal axis of said drive shaft and said longitudinal axis of said container intersect at a point offset from a point equidistant from the top and bottom of said container when said container is clamped to said drive shaft such that said container executes a symmetric wobble motion with a translational component corresponding to the length of said offset as it revolves about said horizontal axis.

12. The apparatus according to Claim 1 wherein said certain angle is 600 such that the longitudinal axis of said container is tilted at an angle of 30° to the vertical when clamped to said drive shaft.

13. The apparatus according to Claim 12 wherein said container is filled with solids to be mixed to a level from 60% to 75% of the distance from the bottom to the top thereof measured along the longitudinal axis of said container when the longitudinal axis of said container is vertical.

Drawing