EP3793717A1 - Mixing apparatus comprising a rotor and a stator - Google Patents

Mixing apparatus comprising a rotor and a stator

Info

Publication number
EP3793717A1
EP3793717A1 EP19804201.2A EP19804201A EP3793717A1 EP 3793717 A1 EP3793717 A1 EP 3793717A1 EP 19804201 A EP19804201 A EP 19804201A EP 3793717 A1 EP3793717 A1 EP 3793717A1
Authority
EP
European Patent Office
Prior art keywords
rotor
mixing
outlet
stator
fluids
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP19804201.2A
Other languages
German (de)
French (fr)
Other versions
EP3793717A4 (en
Inventor
Mikael Löfgren
Niklas Eriksson
Ruben WETIND
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valmet Technologies Oy
Valmet AB
Original Assignee
Valmet Oy
Valmet AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Valmet Oy, Valmet AB filed Critical Valmet Oy
Publication of EP3793717A1 publication Critical patent/EP3793717A1/en
Publication of EP3793717A4 publication Critical patent/EP3793717A4/en
Pending legal-status Critical Current

Links

Classifications

    • 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
    • B01F27/27—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices
    • B01F27/272—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices with means for moving the materials to be mixed axially between the surfaces of the rotor and the stator, e.g. the stator rotor system formed by conical or cylindrical surfaces
    • B01F27/2722—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices with means for moving the materials to be mixed axially between the surfaces of the rotor and the stator, e.g. the stator rotor system formed by conical or cylindrical surfaces provided with ribs, ridges or grooves on one surface
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C7/00—Digesters
    • D21C7/06—Feeding 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
    • B01F27/111—Centrifugal stirrers, i.e. stirrers with radial outlets; Stirrers of the turbine type, e.g. with means to guide the flow
    • 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
    • B01F27/11252—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 paddle wheels
    • 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
    • B01F27/19—Stirrers with two or more mixing elements mounted in sequence on the same axis
    • B01F27/192—Stirrers with two or more mixing elements mounted in sequence on the same axis with dissimilar elements
    • 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
    • B01F27/27—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices
    • 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
    • B01F27/27—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices
    • B01F27/271—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices with means for moving the materials to be mixed radially between the surfaces of the rotor and the stator
    • B01F27/2712—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices with means for moving the materials to be mixed radially between the surfaces of the rotor and the stator provided with ribs, ridges or grooves on one surface
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30—Defibrating by other means
    • D21B1/34—Kneading or mixing; Pulpers
    • D21B1/342—Mixing apparatus
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F2101/00—Mixing characterised by the nature of the mixed materials or by the application field
    • B01F2101/47—Mixing of ingredients for making paper pulp, e.g. wood fibres or wood pulp

Definitions

  • the present invention relates to a mixing apparatus for mixing media or fluids with different density properties and, in particular to a mixing apparatus for mixing treatment media into a fiber suspension, e.g. lignocellulosic pulp
  • the treatment media added to the fiber suspension may for example be for heating, delignification or bleaching purposes. Often the treatment media are in gaseous or liquid state.
  • Cylindrical mixers are provided in a wide range of configurations.
  • the rotor of the mixer may have a center axis aligned with or arranged perpendicularly to the general flow direction of the media.
  • the outlet and inlet of the mixer may both be positioned axially with respect to the center axis of the rotor, or one of the inlet or outlet may be positioned perpendicularly to the center axis of the rotor.
  • An object of the present invention is to provide an improved mixing apparatus for mixing media or fluids with different density properties.
  • Another object of the present invention is to provide an improved mixing apparatus for mixing treatment media into a fiber suspension, e.g. lignocellulosic pulp suspension
  • a mixing apparatus for mixing fluids, for example, a gaseous medium into a pulp
  • the mixing apparatus comprises a housing having a mixing chamber, at least one inlet opening communicating with the mixing chamber.
  • the inlet opening enables fluids to be fed into the mixing chamber.
  • a drive shaft is connectable to a drive device for rotation of the drive shaft in operation and a rotor is arranged in the mixing chamber and is adapted to be connected to the drive shaft to rotate with the drive shaft.
  • At least one outlet is provided in the housing and is communicating with the mixing chamber. The at least one outlet is communicating with an outlet duct for enabling a discharge of mixed fluids.
  • the rotor has a rotor axis extending through the mixing chamber and being concentric with the drive shaft, wherein the rotor includes mixing elements arranged around the rotor and along its extension.
  • the rotor includes a discharge end arranged with discharging elements for discharging the fluids radially.
  • a stator is arranged in the mixing chamber including stator openings allowing mixed fluids discharged by the discharging elements of the rotor to flow radially through the stator openings from the mixing chamber and further toward the at least one outlet, whereby a tangential movement of the discharged fluids is prevented.
  • the present invention is based on the insight that by, during discharge of the fluids, stopping or preventing the remaining rotation of the fluids, e.g. the pulp suspension, and thus the tangential movement of the fluids by means of the stator, the separation of fluids with different density properties caused by the centrifugal force can be minimized. This effect is also improved by the uniform radial discharge of fluids from the mixing zone within the mixing chamber.
  • a center axis of the outlet duct is perpendicularly, e.g. radially, displaced in a direction towards the at least one outlet in relation to a center axis the rotor.
  • an interior volume of the outlet duct increases in proportion to a volume of the discharged fluid in a flow direction.
  • the stator is shaped as tubular element.
  • stator openings is arranged radially adjacent to and outside the discharging elements of the rotor in a flow direction.
  • stator openings are distributed along the stators entire circumference to provide a symmetric discharge flow of fluid.
  • the mixing elements of the rotor are protrusions with a curved or angled trailing surface in a direction of rotation of the rotor.
  • the mixing elements of said rotor are distributed along substantially entire longitudinal extension of the rotor.
  • the discharging elements of the rotor are protrusions curved or angled in a flow direction.
  • the stator is a stator
  • Fig. 1 illustrates a schematical axial cross-section of a first preferred embodiment of the present invention
  • Fig. 2 illustrates a schematical partly cross-sectional view of a first preferred embodiment of the present invention
  • Fig. 3 illustrates a schematical view of the mixing apparatus and the outlet opening in a direction perpendicular to a center axis of the rotor and shaft;
  • Fig. 4 illustrates a schematical cross-section view of the mixing apparatus in a direction along the extension of the center axis of the rotor and shaft;
  • Fig. 5 illustrates schematically the outside of the housing of the mixing apparatus according to the present invention.
  • longitudinal refers to the direction along which a body, part or element has its greatest extension. Further, when the term longitudinal is used in connection with the axes of shafts or similar, the longitudinal axis corresponds to the rotational axis of the shaft or similar.
  • the mixing apparatus 10 comprises a housing 12, wherein the interior thereof is called a homogenization chamber or mixing chamber 14 with an inlet duct 16 having an inlet 18 into the mixing chamber 14. Further, the mixing apparatus 10 comprises an outlet duct 20 having an outlet 22 from the mixing chamber 14 and a rotor 24 arranged axially with the direction of flow from the inlet opening 18 and transverse to the direction of flow to the outlet 22.
  • the housing 12 is, in this embodiment of the present invention, preferably of a cylindrical, shell or helix shaped design, as shown in Fig. 5.
  • the housing 12 is further provided with an end part or end cap 26.
  • the end cap 26 includes a substantially central opening for a shaft 28 of the rotor 24 with necessary sealing, and possibly bearings for the shaft 28.
  • the substantially cylindrical wall of the housing 12 is, as explained above, provided with inlet and outlet 18, 22.
  • the shape of the inlet opening 18 such that a center axis and an axis of symmetry that is concentric with the center axis RR of the rotor 24 and the shaft 28.
  • the outlet 22 is in some embodiments of the present invention shaped as a rectangle as shown in Fig. 3.
  • Fig. 3 illustrates the mixing apparatus 10 and the outlet 22 schematically in a direction perpendicular to a center axis RR of the rotor 24 and shaft 28.
  • the outlet duct 20 is, according to preferred embodiments of the present invention, shaped such that a center axis R ou of the outlet duct 20 is radially displaced in a direction towards the outlet 22 in relation to the center axis RR of the rotor 24 and such that an interior volume of the outlet duct 20 increases in proportion to a volume of the discharged fluid.
  • the rotor 24 is mounted to the shaft 28 in the mixing chamber 14 and rotates with the drive shaft 28.
  • the shaft 28 is driven by a motor, for example, an electrical motor.
  • the rotor 24 has a number of mixing elements 32 arranged around the rotor and along its longitudinal extension.
  • the rotor 24 includes a discharge end 34 arranged with discharging elements 36 for discharging the fluids in a direction substantially radially, in relation to the center axis RR of the rotor 24 towards to outlet 22 and outlet duct 20.
  • the purpose of the mixing elements 32 is to cause turbulence in the fluids or media and thereby to obtain a homogenization or mixing of the fluids or media and to avoid a separation of, for example, gas from a medium.
  • the shape and design of the mixing elements 32 as well as their number and exact location on the rotor and in relation to the inner wall of the housing, to the inlet opening depend on the medium or media to be treated, the consistency of the medium or media, gas content of media, volume flow through the mixing chamber, amount of gas added to medium or media to mention a few influencing parameters.
  • the mixing elements causes a flow of media through the mixing chamber towards the end part of the rotor, where for example, the flow velocity of the medium or media can be regulated by means of the inter alia the rotational speed of the rotor.
  • the mixing elements 32 can, according to certain embodiments, be distributed along the longitudinal extension of the rotor 24 in a gradually dislocated manner such that each line of mixing elements 32 are arranged with an inclination in relation to the center axis RR of the rotor 24. Further, in certain embodiments, the mixing elements 32 are protrusions with a curved or angled trailing surface in a direction of rotation of the rotor 24 and the discharging elements 36 are
  • protrusions curved or angled in a flow direction.
  • a stator 38 is arranged at the end of the mixing chamber 14 adjacent to the outlet 22.
  • the stator 38 comprises a number of stator openings 40 arranged radially adjacent to and outside the discharging elements 36 of the rotor 24 in a flow direction (indicated with arrows).
  • the stator 38 is shaped as tubular element provided inside the housing, for example as an insert lining or attached to the housing by means of for instance bolts or screws.
  • An important purpose of the stator 38 and the stator openings 40 is, in essence, to function as an end of the mixing zone within the mixing chamber 14 and to stop or prevent a tangential movement of the
  • a common problem in prior art mixing devices is a separation of gas from medium during the outflow or discharge caused by remaining rotation in the media since the centrifugal force acts differently on gases compared to liquids or pulp suspensions, for example. This is a pronounced problem when gas is mixed with pulp suspension.
  • FIG. 4 illustrates a schematical cross-section view of the mixing apparatus in a direction along the extension of the center axis RR of the rotor 24 and shaft 28, i.e. the center axis RR of the rotor 24 points out from the figure.
  • the stator 38 is encircled in a radial direction by a discharge space 42 communicating with the mixing chamber 14 via the stator openings 40 and the outlet duct 20 via the outlet 22.
  • the discharge space 42 is delimited by an interior wall 44 of the housing 12, the discharge end 34 of the rotor 24 and the stator 38.
  • the flow of media is indicated with arrows B, C, and D.
  • Arrow B illustrates the flow of media in the mixing chamber 14, where the rotation of the rotor 24 causes turbulence and rotation of media and thereby homogenization and mixing of the media, for example, gaseous medium and pulp suspension.
  • Arrows C illustrate discharge of media through the stator openings 40 and arrows D illustrate the semi-circular flow of media following the interior wall 44 of the housing 12 towards the outlet 22 and then further to the outlet duct 20.
  • the volume of and the width (seen as a distance between the stator 38 and the interior wall 44 of the housing 12) of the discharge space 42 increases in a flow direction.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Mixers Of The Rotary Stirring Type (AREA)

Abstract

According to the present invention, there is provided a mixing apparatus (10) for mixing fluids. The apparatus comprises a housing (12) having a mixing chamber (14). At least one inlet opening (18) communicates with the mixing chamber (14), wherein the inlet opening (18) enabling fluids to be fed into the mixing chamber (14). At least one outlet (22) is provided in the housing (12) and communicates with the mixing chamber (14). A rotor (24) is arranged in the mixing chamber (14) and is adapted to be connected to a drive shaft (28) to rotate with the drive shaft. The rotor (24) includes mixing elements (32) arranged around the rotor (24) and along its extension, wherein the rotor (24) includes a discharge end (34) arranged with discharging elements (36) for discharging the fluids radially. A stator (38) is arranged in the mixing chamber (14) and includes a number of stator openings (40) allowing mixed fluids discharged by the discharging elements (36) of the rotor (24) to flow radially through the stator openings (40) from the mixing chamber (14) and further toward the at least one outlet (22), wherein a tangential movement of the discharged fluids is prevented.

Description

MIXING APPARATUS COMPRISING A ROTOR AND A STATOR
TECHNICAL FIELD
The present invention relates to a mixing apparatus for mixing media or fluids with different density properties and, in particular to a mixing apparatus for mixing treatment media into a fiber suspension, e.g. lignocellulosic pulp
suspension.
BACKGROUND OF THE INVENTION
In many industrial applications, such as within different chemical industries where various chemicals have to be mixed with different suspensions of raw material or into combinations of raw material, it is of high importance to
homogenize media having different properties such as different densities to obtain homogenous suspensions. Such industries include paint manufacturing and pulp and papermanufacturing.
Within the pulp and paper industry, throughout the fiberline, i.e. the different process steps involved when converting wood chips or other fibrous raw material into pulp, there are several positions where mixing apparatuses are used to mix different kind of media into the pulp suspension. The treatment media added to the fiber suspension may for example be for heating, delignification or bleaching purposes. Often the treatment media are in gaseous or liquid state.
When mixing treatment media into a fiber suspension, it is of high importance for the mixing result that an even or homogenous distribution is achieved.
Cylindrical mixers are provided in a wide range of configurations. For example, the rotor of the mixer may have a center axis aligned with or arranged perpendicularly to the general flow direction of the media. Also, the outlet and inlet of the mixer may both be positioned axially with respect to the center axis of the rotor, or one of the inlet or outlet may be positioned perpendicularly to the center axis of the rotor. In many cylindrical mixer configurations, particularly wherein the outlet is arranged perpendicularly to the inlet and a center axis of the outlet is perpendicular to a center axis of the rotor, or in a tangential direction in relation to the rotor, there is a remaining rotation of the media flowing out from the mixer, e.g. the pulp suspension. This remaining rotation of the pulp suspension may cause a separation of media or fluids when the mixed media have different densities due to the centrifugal force, which is an undesired phenomenon particularly frequent when gaseous media are mixed with media with higher density such as pulp.
Thus, there is a need for improved mixing apparatuses for mixing media or fluids with different density properties and, in particular, for mixing apparatuses for mixing treatment media into a fiber suspension, e.g. lignocellulosic pulp
suspension.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an improved mixing apparatus for mixing media or fluids with different density properties.
Another object of the present invention, is to provide an improved mixing apparatus for mixing treatment media into a fiber suspension, e.g. lignocellulosic pulp suspension
These and other objects are achieved by the present invention by means of a mixing apparatus for mixing media or fluids according to the claims.
According to an aspect of the present invention, there is provided a mixing apparatus for mixing fluids, for example, a gaseous medium into a pulp
suspension. The mixing apparatus comprises a housing having a mixing chamber, at least one inlet opening communicating with the mixing chamber. The inlet opening enables fluids to be fed into the mixing chamber. A drive shaft is connectable to a drive device for rotation of the drive shaft in operation and a rotor is arranged in the mixing chamber and is adapted to be connected to the drive shaft to rotate with the drive shaft. At least one outlet is provided in the housing and is communicating with the mixing chamber. The at least one outlet is communicating with an outlet duct for enabling a discharge of mixed fluids. The rotor has a rotor axis extending through the mixing chamber and being concentric with the drive shaft, wherein the rotor includes mixing elements arranged around the rotor and along its extension. The rotor includes a discharge end arranged with discharging elements for discharging the fluids radially. A stator is arranged in the mixing chamber including stator openings allowing mixed fluids discharged by the discharging elements of the rotor to flow radially through the stator openings from the mixing chamber and further toward the at least one outlet, whereby a tangential movement of the discharged fluids is prevented.
The present invention is based on the insight that by, during discharge of the fluids, stopping or preventing the remaining rotation of the fluids, e.g. the pulp suspension, and thus the tangential movement of the fluids by means of the stator, the separation of fluids with different density properties caused by the centrifugal force can be minimized. This effect is also improved by the uniform radial discharge of fluids from the mixing zone within the mixing chamber.
According to an embodiment of the present invention, a center axis of the outlet duct is perpendicularly, e.g. radially, displaced in a direction towards the at least one outlet in relation to a center axis the rotor.
In embodiments of the present invention, an interior volume of the outlet duct increases in proportion to a volume of the discharged fluid in a flow direction.
According to embodiments of the invention, the stator is shaped as tubular element.
In embodiments of the invention, the stator openings is arranged radially adjacent to and outside the discharging elements of the rotor in a flow direction.
According to embodiments of the invention, the stator openings are distributed along the stators entire circumference to provide a symmetric discharge flow of fluid.
In embodiments of the invention, the mixing elements of the rotor are protrusions with a curved or angled trailing surface in a direction of rotation of the rotor.
According to embodiments of the invention, the mixing elements of said rotor are distributed along substantially entire longitudinal extension of the rotor.
In embodiments of the present invention, the discharging elements of the rotor are protrusions curved or angled in a flow direction.
According to embodiments of the present invention, the stator is
encircled in a radial direction by a discharge space delimited by an interior wall of the housing, the discharge end of the rotor and the stator. The discharge space communicates with the outlet duct via the at least one outlet, wherein, during operation, fluids are forced to flow through the stator openings and in a semi- circular flow in the discharge space towards the at least one outlet and outlet duct. Further advantageous embodiments of the device according to the present invention and further advantages of the present invention emerge from the de- tailed description of embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described, for exemplary purposes, in more detail by way of embodiments and with reference to the enclosed drawings, in which:
Fig. 1 illustrates a schematical axial cross-section of a first preferred embodiment of the present invention;
Fig. 2 illustrates a schematical partly cross-sectional view of a first preferred embodiment of the present invention;
Fig. 3 illustrates a schematical view of the mixing apparatus and the outlet opening in a direction perpendicular to a center axis of the rotor and shaft;
Fig. 4 illustrates a schematical cross-section view of the mixing apparatus in a direction along the extension of the center axis of the rotor and shaft;
Fig. 5 illustrates schematically the outside of the housing of the mixing apparatus according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the drawings, similar or corresponding elements are denoted by the same reference numbers. Generally, in the drawings, arrows indicate the direction of the flow of fluid in the mixing apparatus, into and out of the mixing apparatus.
For the purpose of this disclosure, the term longitudinal refers to the direction along which a body, part or element has its greatest extension. Further, when the term longitudinal is used in connection with the axes of shafts or similar, the longitudinal axis corresponds to the rotational axis of the shaft or similar.
With reference first to Fig. 1 , the mixing apparatus 10 comprises a housing 12, wherein the interior thereof is called a homogenization chamber or mixing chamber 14 with an inlet duct 16 having an inlet 18 into the mixing chamber 14. Further, the mixing apparatus 10 comprises an outlet duct 20 having an outlet 22 from the mixing chamber 14 and a rotor 24 arranged axially with the direction of flow from the inlet opening 18 and transverse to the direction of flow to the outlet 22. The housing 12 is, in this embodiment of the present invention, preferably of a cylindrical, shell or helix shaped design, as shown in Fig. 5. The housing 12 is further provided with an end part or end cap 26. The end cap 26 includes a substantially central opening for a shaft 28 of the rotor 24 with necessary sealing, and possibly bearings for the shaft 28.
The substantially cylindrical wall of the housing 12 is, as explained above, provided with inlet and outlet 18, 22. Preferably, the shape of the inlet opening 18 such that a center axis and an axis of symmetry that is concentric with the center axis RR of the rotor 24 and the shaft 28.
The outlet 22 is in some embodiments of the present invention shaped as a rectangle as shown in Fig. 3. Fig. 3 illustrates the mixing apparatus 10 and the outlet 22 schematically in a direction perpendicular to a center axis RR of the rotor 24 and shaft 28.
The outlet duct 20 is, according to preferred embodiments of the present invention, shaped such that a center axis Rou of the outlet duct 20 is radially displaced in a direction towards the outlet 22 in relation to the center axis RR of the rotor 24 and such that an interior volume of the outlet duct 20 increases in proportion to a volume of the discharged fluid.
Flence, the rotor 24 is mounted to the shaft 28 in the mixing chamber 14 and rotates with the drive shaft 28. The shaft 28 is driven by a motor, for example, an electrical motor. The rotor 24 has a number of mixing elements 32 arranged around the rotor and along its longitudinal extension.
Further, the rotor 24 includes a discharge end 34 arranged with discharging elements 36 for discharging the fluids in a direction substantially radially, in relation to the center axis RR of the rotor 24 towards to outlet 22 and outlet duct 20.
The purpose of the mixing elements 32 is to cause turbulence in the fluids or media and thereby to obtain a homogenization or mixing of the fluids or media and to avoid a separation of, for example, gas from a medium. Flowever, as the skilled person realizes, the shape and design of the mixing elements 32 as well as their number and exact location on the rotor and in relation to the inner wall of the housing, to the inlet opening, depend on the medium or media to be treated, the consistency of the medium or media, gas content of media, volume flow through the mixing chamber, amount of gas added to medium or media to mention a few influencing parameters. In addition to cause turbulence, the mixing elements causes a flow of media through the mixing chamber towards the end part of the rotor, where for example, the flow velocity of the medium or media can be regulated by means of the inter alia the rotational speed of the rotor.
The mixing elements 32 can, according to certain embodiments, be distributed along the longitudinal extension of the rotor 24 in a gradually dislocated manner such that each line of mixing elements 32 are arranged with an inclination in relation to the center axis RR of the rotor 24. Further, in certain embodiments, the mixing elements 32 are protrusions with a curved or angled trailing surface in a direction of rotation of the rotor 24 and the discharging elements 36 are
protrusions curved or angled in a flow direction.
A stator 38 is arranged at the end of the mixing chamber 14 adjacent to the outlet 22. The stator 38 comprises a number of stator openings 40 arranged radially adjacent to and outside the discharging elements 36 of the rotor 24 in a flow direction (indicated with arrows).
Preferably, the stator 38 is shaped as tubular element provided inside the housing, for example as an insert lining or attached to the housing by means of for instance bolts or screws. An important purpose of the stator 38 and the stator openings 40 is, in essence, to function as an end of the mixing zone within the mixing chamber 14 and to stop or prevent a tangential movement of the
discharged fluids when entering into and flowing through the stator openings 40.
A common problem in prior art mixing devices is a separation of gas from medium during the outflow or discharge caused by remaining rotation in the media since the centrifugal force acts differently on gases compared to liquids or pulp suspensions, for example. This is a pronounced problem when gas is mixed with pulp suspension.
Turning now to Fig. 4 which illustrates a schematical cross-section view of the mixing apparatus in a direction along the extension of the center axis RR of the rotor 24 and shaft 28, i.e. the center axis RR of the rotor 24 points out from the figure. As shown in Fig. 4, the stator 38 is encircled in a radial direction by a discharge space 42 communicating with the mixing chamber 14 via the stator openings 40 and the outlet duct 20 via the outlet 22.
The discharge space 42 is delimited by an interior wall 44 of the housing 12, the discharge end 34 of the rotor 24 and the stator 38. In Fig. 4, the flow of media is indicated with arrows B, C, and D. Arrow B illustrates the flow of media in the mixing chamber 14, where the rotation of the rotor 24 causes turbulence and rotation of media and thereby homogenization and mixing of the media, for example, gaseous medium and pulp suspension. Arrows C illustrate discharge of media through the stator openings 40 and arrows D illustrate the semi-circular flow of media following the interior wall 44 of the housing 12 towards the outlet 22 and then further to the outlet duct 20. As can be seen in Fig. 4, the volume of and the width (seen as a distance between the stator 38 and the interior wall 44 of the housing 12) of the discharge space 42 increases in a flow direction.
The invention shall not be considered limited to the embodiments illus- trated, but can be modified and altered in many ways by one skilled in the art, without departing from the scope of the appended claims.

Claims

1. A mixing apparatus (10) for mixing fluids comprising:
a housing (12) having a mixing chamber (14), at least one inlet opening (18) communicating with the mixing chamber (14), said inlet opening (18) enabling fluids to be fed into the mixing chamber (14),
a drive shaft (28) connectable to a drive device for rotation of the drive shaft (28) in operation,
at least one outlet (22) provided in the housing (12) and
communicating with the mixing chamber (14), said at least one outlet (22) communicating with an outlet duct (20) for enabling a discharge of mixed fluids;
a rotor (24) arranged in said mixing chamber (14) adapted to be connected to the drive shaft (28) to rotate with said drive shaft (28), said rotor (24) having a center axis (RR) extending through the mixing chamber (14) and being concentric with said drive shaft (28), said rotor (24) including mixing elements (32) arranged around said rotor (24) and along its extension, wherein said rotor (24) includes a discharge end (34) arranged with discharging elements (36) for discharging the fluids radially; and
a stator (38) arranged in said mixing chamber (14) including stator openings (40) allowing mixed fluids discharged by the discharging elements (36) of the rotor (24) to flow radially through said stator openings (40) from the mixing chamber (14) and further toward the at least one outlet (22), whereby a tangential movement of the discharged fluids is prevented.
2. The mixing apparatus according to claim 1 , wherein a center axis (Rou) of the outlet duct in said housing (12) is perpendicularly displaced in a direction towards the at least one outlet (22) in relation to a center axis (RR) of said rotor (24).
3. The mixing apparatus according to claim 2, wherein an interior volume of said outlet duct (20) increases in proportion to a volume of the discharged fluid in a flow direction.
4. The mixing apparatus according to any one preceding claims, wherein said stator (38) is shaped as tubular element.
5. The mixing apparatus according to any one preceding claims, wherein the stator openings (40) are arranged radially adjacent to and outside said discharging elements (36) of said rotor (24) in a flow direction.
6. The mixing apparatus according to any one of preceding claims, wherein said stator openings (40) are distributed along the stators (38) entire circumference to provide a symmetric discharge flow of fluid.
7. The mixing apparatus according to any one of preceding claims, wherein said mixing elements (32) of said rotor (24) are protrusions with a curved or angled trailing surface in a direction of rotation of the rotor (24).
8. The mixing apparatus according to any one of preceding claims, wherein said mixing elements (32) of said rotor (24) are distributed along
substantially entire longitudinal extension of the rotor (24).
9. The mixing apparatus according to any of the preceding claims, wherein said discharging elements (36) of said rotor (24) are protrusions curved or angled in a flow direction.
10. The mixing apparatus according to any of preceding claims, wherein the stator (38) is encircled in a radial direction by a discharge space (42), said discharge space (42) being delimited by an interior wall (44) of said housing (12), said discharge end (34) of the rotor (24) and said stator (38), said discharge space (42) communicating with the outlet duct (20) via the at least one outlet (22), wherein during operation fluids are forced to flow through the stator openings (40) and in a semi-circular flow in the discharge space (42) towards the at least one outlet (22) and outlet duct (20).
EP19804201.2A 2018-05-18 2019-04-09 Mixing apparatus comprising a rotor and a stator Pending EP3793717A4 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1850579A SE542677C2 (en) 2018-05-18 2018-05-18 Mixing apparatus comprising a rotor and a stator
PCT/SE2019/050326 WO2019221652A1 (en) 2018-05-18 2019-04-09 Mixing apparatus comprising a rotor and a stator

Publications (2)

Publication Number Publication Date
EP3793717A1 true EP3793717A1 (en) 2021-03-24
EP3793717A4 EP3793717A4 (en) 2022-03-02

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EP19804201.2A Pending EP3793717A4 (en) 2018-05-18 2019-04-09 Mixing apparatus comprising a rotor and a stator

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CN (1) CN112118903A (en)
SE (1) SE542677C2 (en)
WO (1) WO2019221652A1 (en)

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Publication number Priority date Publication date Assignee Title
CN115999392A (en) * 2022-12-07 2023-04-25 深圳市尚水智能股份有限公司 Centrifugal dispersing device
CN116020302A (en) * 2022-12-07 2023-04-28 深圳市尚水智能股份有限公司 Shearing and dispersing device and continuous pulping equipment

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SU1331547A1 (en) * 1985-10-31 1987-08-23 Ленинградское Специальное Конструкторское Бюро Всесоюзного Научно-Производственного Объединения Целлюлозно-Бумажной Промышленности Apparatus for mixing fibrous suspension with reagents
US5863120A (en) * 1997-01-31 1999-01-26 Beloit Technologies, Inc. Medium consistency liquid mixture
US6309788B1 (en) * 1998-11-06 2001-10-30 Canon Kabushiki Kaisha Process for producing toner
AUPQ503900A0 (en) * 2000-01-11 2000-02-03 Commonwealth Scientific And Industrial Research Organisation Apparatus for mixing
GB0326233D0 (en) * 2003-11-11 2003-12-17 Power Technologies Invest Ltd System and method for pulverising and extracting mositure
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JP6077469B2 (en) * 2011-02-28 2017-02-08 スルザー ミックスパック アクチェンゲゼルシャフト Dynamic mixer
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US11419451B2 (en) * 2016-08-08 2022-08-23 Plant Tap, LLC Apparatus and method for producing beverages from dry ingredients

Also Published As

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SE1850579A1 (en) 2019-11-19
WO2019221652A1 (en) 2019-11-21
EP3793717A4 (en) 2022-03-02
CN112118903A (en) 2020-12-22
SE542677C2 (en) 2020-06-23

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