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
  • B01F25/30—Injector mixers
  • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
  • B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
  • B01F25/3132—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit by using two or more injector devices
• • 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
  • B01F27/11—Stirrers characterised by the configuration of the stirrers
  • B01F27/112—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades
  • B01F27/1125—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades with vanes or blades extending parallel or oblique to the stirrer axis
• • 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
  • B01F27/50—Pipe mixers, i.e. mixers wherein the materials to be mixed flow continuously through pipes, e.g. column mixers
• • 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
  • B01F27/80—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis
  • B01F27/84—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis with two or more stirrers rotating at different speeds or in opposite directions about the same axis

Definitions

• the invention described herein pertains generally to pulp processing equipment, and more particularly to an apparatus and method for mixing low or medium consistency pulp with at least one chemical reagent.
• a simple, inexpensive mixer for pulp plant bleaching operations which promotes uniform distribution of the bleaching chemicals so that the residence time in the bleaching tower is maximized. It is an object of this invention to provide a high turbulence mixer which uses a vaned hollow cage rotor in combination with a tongued stator.
• Fig. 1 is a perspective view of a hollow cage rotor showing four vanes
• Fig. 2 is a perspective view of a tongued adjustable stator
• Fig. 3 is a side view in partial cross-section showing the hollow cage rotor and stator inline of a mixer wherein the inlet and exit sections are in essentially linear alignment
• Fig. 4 is a side view in partial cross-section showing the hollow cage rotor and stator inline of a mixer wherein the inlet and exit sections are not in linear alignment
• Fig. 5 is a cross-sectional view shown in partial cross-section along line 4- 4 of Fig. 4.
• the mixer 50 of the invention comprises the combination of a hollow cage rotor 10 in association with a tongued adjustable stator 20.
• the hollow cage rotor comprises a variable number of vanes 6 (ranging from at least 2 to 12 in number), the vanes physically connected to a rotor base 8 and a rotor boss 4 at opposed ends of the vanes.
• a rotating shaft 2 is typically affixed to rotor boss 4 centered about the axis of rotation of the rotor.
• the rotor may be pulley or direct-driven depending upon the application.
• the number of vanes is generally dependent upon mixer size, piping capacity and pulp consistency.
• the vanes serve to maintain the coaxial relationship of the rotor boss and rotor base and can have many different geometries.
• the vanes can be perpendicular to the bottom surface of the rotor boss with the longitudinal axis of any one vane in parallel alignment with the longitudinal axis of the rotating shaft, or skewed or even spiraled wherein the vanes are usually equally spaced about the circumference of the rotor boss but for which an axis drawn between the attachment points of the vane to the rotor boss and rotor base would not result in a parallel alignment with the longitudinal axis of the rotating shaft.
• the diameter of the rotor base 8 is essentially the same as that of the rotor boss 4. However, in certain specialized instances, the diameter of the rotor base may be larger or smaller than the rotor boss.
• the vanes may once again, either be in essentially a straight line configuration emanating from the bottom surface of the rotor boss and terminating at the rotor base, or in a skewed or even spiral configuration.
• the stator 20 comprises a tongue 14, which fits inside the rotor cage.
• the stator can be concentric or off-set depending upon the application.
• the tongue of the stator in a preferred embodiment, has at least one tongue foil 16 about the periphery of the tongue.
• the arrangement of the foils can be normal to the surface of the tongue as shown, or the tongue foils can be in a spiral configuration about the stator tongue. While not shown in Fig. 2, it is possible for the stator to also have a rotation shaft in a manner similar to that shown in Fig. 1 for the rotor.
• the high turbulence mixer is positioned in a transverse direction to the inline pulp ⁇ iquor stream 22.
• the flanged piping 26 has an entry section 40, a mixing zone 42 and an exit section 44.
• Pulp ⁇ iquor 22 is received into the entry section 40 and bleaching chemicals are added through chemical entry nozzle 28, optionally fitted with a directional flap 52 for use in channeling the flow of the chemicals into the pulp stream.
• mixing zone 42 wherein a tongued stator 20 is positioned inside of rotating hollow cage rotor 10.
• the mixture of pulp and liquor is subjected to intense turbulence and shear forces in mixing zone 42.
• the stator tongue 14 is concentric or off-set of the longitudinal axis 34 of the hollow cage rotor shaft 2.
• hollow cage rotor rotates about the tongued stator creating two mixing intensities in the same device, i.e., on the outlet side, higher shear forces will be generated due to the smaller gap between the rotor and the stator, while on the inlet side, a milder turbulence will be generated due to the wider gap.
• both the hollow cage rotor and tongued stator rotate.
• the rotation of the hollow cage rotor is opposite to that of the tongued stator.
• Alternative configurations for the mixer 50 are also envisioned. As shown in Fig. 4, the exit section 44 need not be oriented in longitudinal alignment with the entry section 40. It is also within the scope of this invention to have the chemical addition occur at a point other than that identified previously as chemical entry nozzle 28. In some instances, it may be desirable to add the chemicals into the turbulence created at the rotor/stator interface. This type of configuration is shown in Fig. 3 where the chemical addition occurs through orifices 48 positioned either along the longitudinal axis of stator tongue 14 or through orifices 18 on the tongue.
• Fig. 5 shows a cross-section of Fig. 4 taken along line A-A.
• the offset 36 of the tongue 14 in comparison to the longitudinal axis 34 of the stator is evident.
• the distance between the tongue of the stator and the inside of the rotor vanes 6 can be adjusted to suit the target application.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mixers Of The Rotary Stirring Type (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22255208

Family Applications (1)

Country Status (5)

Families Citing this family (5)

Family Cites Families (10)

• 1996
  • 1996-06-03 WO PCT/US1996/008551 patent/WO1997046310A1/en not_active Application Discontinuation
  • 1996-06-03 CA CA002257267A patent/CA2257267A1/en not_active Abandoned
  • 1996-06-03 EP EP96917064A patent/EP0912236A1/de not_active Withdrawn
  • 1996-06-03 JP JP10500511A patent/JPH11511694A/ja active Pending
• 1997
  • 1997-06-03 ID IDP971890A patent/ID17739A/id unknown

Non-Patent Citations (1)

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