Classifications

• • 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
  • B01F25/80—Falling particle mixers, e.g. with repeated agitation along a vertical axis
  • B01F25/82—Falling particle mixers, e.g. with repeated agitation along a vertical axis uniting flows of material taken from different parts of a receptacle or from a set of different receptacles
  • B01F25/821—Falling particle mixers, e.g. with repeated agitation along a vertical axis uniting flows of material taken from different parts of a receptacle or from a set of different receptacles by means of conduits having inlet openings at different levels

Definitions

• This invention relates to blenders and more specifically to methods and apparatus for thoroughly blending particulate or granular materials, a portion of the unblended material forming a toroidal block, constituting a virtual baffle to the downward flow of any particulate material except that passing through the blending tubes themselves.
• baffle--(noun) a plate, wall, screen, or other device to deflect, check, or regulate flow.
• virtual baf le herein defined as a barrier, formed of particulate material, in combination with a supporting structural matrix, to the downward flow of particulate material, except through blending tubes which penetrate the barrier.
• matrix herein defined as blender walls, metallic plates and cones, blending conduits, all coacting with the particulate material to provide the virtual baffle.
• voussoir (diet . ) one of the wedge-shaped pieces forming an arch or vault. Used herein to graphically describe the cross section of the virtual baffle, at some point on the toroid or segment.
• bridging the tendency of particulate solids, flowing downward through a channel with converging sides, to bridge across the channel, blocking the channel, causing all of the material flowing out of the blender to flow through the blending tubes.
• toroidal block herein, a toroidal mass of particulate material, having a voussoi r-1ike crossection, supported between the outer wall of the blender and the downwardly converging metal baffles of FIGs. 6 and 9. Also called a toroidal or annular "keystone joist.”
• Prior art attempts at a solution to this segregation problem typically included placing perforated blending tubes vertically within the hopper. Such tubes have openings spaced apart along their axes which allow material from all levels within the hopper to enter the tubes. The lower portion of the blending tubes communicate with the outlet nozzle so that a more nearly homogeneous mixture of the material issues from the outlet of the hopper.
• My invention in two preferred embodiments disclosed herein, in combination with a conventional hopper and conventional blending tubes, can effectively blend a batch of particulate material, including the final portion of the batch.
• my invention simulates the operation of tne full size blender, in an adjustable laboratory size model, enabling experimentation with various particulate densities, compactabilities and annular gaps.
• My invention does not require ji separate blending chamber. It utilizes the tendency of particulate solids, flowing downward through a channel with converging sides, to bridge across the channel, blocking the channel, causing all of the material flowing out of the blender to flow through the blending tubes. Thus my invention assures that all of the material discharged from the blender represents a truly typical composite of the blender contents.
• a toroidal block having a voussoir-1ike crosssection, as shown in the blender of FIG. 6, and equivalent supporting structure for bridging by particulate materials, as shown in FIGs. 2, 4, 7, 8 and 10.
• FIG. 1 provides an elevational, sectional view? through the center line of a typical blender of the prior art
• FIG. 2 provides an elevational, sectional view through the center line of one preferred embodiment of the gravity blender of the present invention
• FIG. 3 provides a schematic diagram of the hopper, piping and pumps, if required for extremely uniform blending within the gravity blender of the present invention
• FIG. 4 provides a sectional view from the vertical centerline through the exterior wall of the lower portion of the hopper of an alternate embodiment of the present invention, including a detail of a blending tube and a conduit for exhaust gases, or for structural purposes;
• FIG. 5 is a section of the conduit of FIG. 4, illustrating the knife-like device for preventing accumulation of particulate matter on the top surface of the conduit ;
• FIG. 6 is a more detailed view of Embodiment A of the present invention, as combined with terminations of the conventional blending tubes;
• FIG. 7 is a more detailed view of alternate Embodiments A and C of the present invention as combined with two convex surfaces for better blending of virtually all of the material to be blended;
• FIG. 8 provides an elevational, sectional view through the center line of a gravity blender of an alternate embodiment A of the present invention, in which one basic convex surface is combined with a cylindrical device, developed further in FIG. 12-13, for further blending;
• FIG. 9, Embodiment B provides a vertical, sectional view through the center line of the test apparatus, which substantially duplicates the conditions within, and operations of blending of the present invention?
• FIG. 10 provides a sectional view from the vertical centerline through the exterior wall of the lower portion of the hopper of an alternate embodiment of the present invention, including a detail of a blending tube, but without a venting conduit for exhaust gasesj
• FIG. 11 provides a fragmented elevational hemicy1indrical inside view, through a section in the plane including the vertical centerline of a blender, utilizing a virtual baffle of particulate material, supported partially on a matrix of converging blending tubes, and equipped with a small inverted cone. Two partial sectional details are provided ⁇
• FIG. 11A is a fragmentary section just inside the wall 1112, showing the ends 1114 of the blending tubes 1110 within the toroidal block 1130 of particulate materialj
• FIG. 11B shows various angles of cut off of the discharge ends 1114 of the blending tubes 1110
• Embodiment C provides an elevational hemicylindrical inside view, through a section in the plane including the vertical centerline of a blender, utilizing a virtual baffle of particulate material, supported solely on a matrix of converging blending tubes, without an inverted cone, but with a vertical tubular element ⁇ ⁇ n ⁇
• FIG. 13, Embodiment C provides a generally horizontal sectional view through the blender of FIG. 12, at approximately the level of the virtual baffle of particulate material, supported partially on a matrix of converging blending tubes and the vertical tubular element 1240.
• FIG. 1 is shown a drawing from Patent No. 3,268,215, issued to T.A. Burton for a Blending Apparatus on August 23, 1966.
• Illustrative of this prior art are tank or hopper 10, blending tubes 24, and separate receiver or collector manifold 28.
• FIG. 2 shows the similarities and the differences between the prior art of FIG. 1 and the present invention. Similarities include a cylindrical housing 210 superimposed upon and sealed to a conical structure 211. Downcomer tubes 224 however, terminate in perforations 227 through the inverted generally horizontal baffle ' 225, comprising part of the present invention. This means of termination is a significant improvement over the prior art shown in FIG. 1, in which tubes 24 pass entirely through the hopper 10 and terminate in receiver 28. In the annular area 226, between the converging walls of baffle 225 and structure 211, the accumulation of particulate matter forms a toroidal block to the passage of the particulate matter accumulating above the block.
• FIG. 3 diagrams 302 and 303.
• My invention deals with the problem in novel fashion.
• the blending tubes of which tube 602 is an example, terminate in apertures 603. These apertures are formed in the convex surface 604. This means of termination is a significant departure from the prior art, as shown in FIG. 1, in which tubes 24 pass entirely through the hopper 10 and terminate in receiver 28.
• convex surface 604 is supported upon brackets 606, and is thus spaced away from the exterior cone 610 by an annular gap shown as 605.
• annular gaps 605, and apertures 603, are designed as will be shown in connection with the description of FIG. 9, the material to be blended will begin to fill the hopper 601, but will form a barrier at the annulus 605, past which barrier the particulate material will not descend, until blending tubes are evacuated.
• the level of the material will fall below the seam line 607, and then past a series of apertures 608.
• the discharge of material from the blender will then flow preferentially from the blending tubes 602, with essentially zero flow through the annulus 605 between the inverted cone and the vessel cone. Flow through this annulus 605 cannot occur until the supply of maternal coming from the blend tubes 602 is exhausted.
• FIG. 9 is a diagram of the Test Apparatus, i l ⁇ i ⁇ istratin ⁇ its similarity in construction to the blenders ofurthe present invention.
• Material 901 is cross hatched. or clarity.
• Material 902 is shown crosshatched at ⁇ other angle.
• the inverted cone may be set in a position 911 and provides a smaller annular gap 903 than were it raised to a higher position, say 912.
• Material 901 is first poured into the inverted cone, upright cone and standpipe at the start of test, filling volumes shown as underlined 1,2,3,4 and 5. Material 902 may be then put in to fill the remainder of the vessel and will fill to the annular surface 909, in "keystone fashion," as a toroidal block, or as a voussoir of particulate material.
• Material 902 will not flow out of the vessel until the supply of Material 901 is exhausted.
• a. The flow of material from the center nozzle must be regulated by valve 914 to a rate below that would cause voids to form in material 901.
• b. Flow properties of material 901 and 902 should be similar.
• test procedure if properly performed, can provide valuable information on the dimensions 903, 909, and other critical factors in full-size blender design.
• FIG. 11 illustrates the use of an inverted baffle through which the blending tubes 1110 do not penetrate, but which is positioned in such a manner that a voussoir of particulate material is formed between converging surfaces in close proximity to each other.
• this blender particulate material is entrapped within the matrix of conduits 1110 and small inverted cone 1113 mounted on brackets 1106 within the cone of the outer wall 1112.
• the density, particle shape, compactabi1ity, and a host of indeterminate factors will cooperate to establish a toroidal block of material 1130, thus creating a virtual baffle of particulate material, supported partially on a matrix of converging blending tubes 1110, a small inverted cone 1113, and lower section wall 1112.
• FIG. 12 illustrates the accumulation of particulate material 1230 in this blender, when entrapped within the matrix of conduits 1210, and within the cone of the outer wall 1212.
• This embodiment is not equipped with an inverted cone 1113, but has instead a vertical tubular element 1240.
• a voussoir of particulate material 1230 will be formed, creating a virtual baffle, in the form of a toroidal block, between and among the structural members, including the central tubular structure 1240.
• the diameter of the tube 1240 is drawn too large in comparison with the area 1233 provided for discharge of the particulate material, but the concept is adequately presented.
• the density, particle shape, compactabi 1ity, and a host of indeterminate factors will cooperate to establish the position, volume, and mass of material 1230. These parameters will be those required to obtain a suitable toroidal block, utilizing a virtual baffle of particulate material, supported partially on a matrix of converging blending tubes 1210 and vertical tubular element 1240. It must be understood that this drawing is purely illustrative of the inventive concept, and that other variations are within the scope the following claims.
• FIG. 13 provides a horizontal sectional view through the blender of FIG. 12, at approximately the level of the virtual baffle 1230 of particulate material, supported partially on a matrix of converging blending tubes 1210. Further support is provided by the vertical tubular structure 1240.
• the blender uses a number of blending tubes or channels which terminate at the same elevation adjacent to a small inverted cone 1113 as shown in FIG. 11, or without an inverted cone as shown in FIGs. 12 and 13.
• the converging blending conduits provide only limited support to the blocking accumulation of the particulate material
• the major part of the mass of particulate material is supported by the converging matrix of conduits.
• the entire mass of particulate material is supported by the converging matrix of blending conduits and the vertical tubular element 1240.
• FIG. 11 illustrates an alternate embodiment and a more economical method of construction than that of FIG. 7, achieved by eliminating the large baffle 704, and the "hard" terminations of the blending tubes in apertures in the sides of cone 704.
• Blending tubes 1110 are mounted close to the conical wall 1112. Blending tubes 1110 do not terminate in apertures or hubs in the surface of cone 1113, but terminate in the approximate region delineated as 1114, which has a variable vertical range as shown by the two-headed arrow at 1123.
• the base line of the lower end of cone 1113 may vary above or below a typical position 1114, as shown by bidirectional arrow 1123. If proper proportions are selected, such a grid of blending tubes converging toward plane 1114, in combination with the converging wall 1112 of the lower bin section 1101, can support a voussoir 1130 of particulate material, extending slightly downward or upward from reference plane 1114.
• FIG. 11A various terminations for the blending tubes may be employed.
• the intent of this disclosure is to illustrate the concept of a baffle primarily of particulate material, simpler to build and less costly in material.
• the specific terminations of blending conduits, patterns of the matrix, and use or nonuse of small convex cones are all minor variations contemplated in the general use of this invention.
• FIG. 12 is shown an embodiment which does not use the small inverted baffle or cone 1113, a preferred construction being the structural tubing 1240.
• the conical wall 1112 in combination with the blending tube matrix 1110 may ' support the toroidal blocking mass of material 1120 without member 1240.
• FIG. 13 The section shown in FIG. 13 is typical of many usable designs.
• the intent of this disclosure is to illustrate the concept of a baffle primarily of particulate material, simpler to build and less costly in material.
• the specific terminations of blending conduits, patterns of the matrix, and use or nonuse of small convex cones are all minor variations contemplated in the general use of this invention.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Accessories For Mixers (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Applications Claiming Priority (7)

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• 1992
  • 1992-04-09 WO PCT/US1992/002890 patent/WO1992018229A1/en active IP Right Grant
  • 1992-04-09 DE DE69222920T patent/DE69222920T2/de not_active Expired - Lifetime
  • 1992-04-09 ES ES92910728T patent/ES2109356T3/es not_active Expired - Lifetime
  • 1992-04-09 EP EP92910728A patent/EP0538445B1/de not_active Expired - Lifetime
  • 1992-04-09 AU AU18875/92A patent/AU1887592A/en not_active Abandoned
  • 1992-04-09 CA CA002087178A patent/CA2087178C/en not_active Expired - Lifetime
• 1998
  • 1998-04-09 HK HK98103011A patent/HK1003826A1/xx not_active IP Right Cessation

Patent Citations (4)

Non-Patent Citations (1)

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