Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/20—Mixing gases with liquids
  • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
  • B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring 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
  • B01F27/05—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
  • B01F27/117—Stirrers provided with conical-shaped elements, e.g. funnel-shaped

Definitions

• the invention relates to a stirring device for activated sludge according to the preamble of patent claim 1.
• Such a device is known for example from DE 42 18 027 Al or DE 198 26 098 C2.
• a hyperboloid-like stirring body is attached to a shaft.
• On an upper side of the stirring body a plurality of radially inclined transport ribs are provided.
• a flow directed away from the peripheral edge of the stirring body is generated in a stirring medium surrounding liquid medium.
• the invention is based on the object to provide a stirring device with improved stirring efficiency.
• a flow guiding device surrounding the peripheral edge of the stirring body and relatively fixed to guide the flow generated by the stirring body in a plane extending substantially perpendicular to the shaft.
• the invention is based on the finding that the stirring efficiency increases with an increasing radial range of the flow directed away from the peripheral edge of the stirring body. It has been observed that as a result of the flow, forms a not inconsiderable suction below the stirring body, which causes a reverse flow opposite to the flow. The return flow slows the flow and inhibits the formation of a wide radial range of the same.
• the flow generated by the stirring body is guided in a plane extending substantially perpendicular to the shaft, in particular the formation of flow components directed obliquely to the bottom of the basin is counteracted. A mutual influence of the flow and the return flow is reduced. Thus, the radial range of the flow can be significantly improved.
• the transport ribs expediently form, at least in the region of the peripheral edge with the radial direction, a first skew angle of -30 ° to -90 °, preferably -40 ° to -80 °. With the above-mentioned negative sign before the amount of the first skew angle, it is indicated that this opens with respect to the radial direction opposite to the direction of rotation.
• the flow-guiding device has an annular gap surrounding the peripheral edge, which is formed by lower and upper flow-guiding means arranged coaxially with the shaft.
• the flow-guiding means may be made of plastic, in particular fiber-reinforced plastic, or also of metal, preferably of stainless steel, flat elements.
• the flow-guiding device forms an assembly unit.
• the upper and lower flow guiding means can be connected to each other via connecting means.
• the connecting means may be substantially radially extending walls. The provision of such walls contributes to an improved flow tion in the radial direction and thus further to increase the scope of the flow.
• the connecting means are obliquely extending first inclined walls with respect to the radial direction, which form with the radial direction a second skew angle of + 30 ° to + 90 °, preferably + 40 ° to + 80 °.
• the positive sign used before the magnitude of the aforementioned second skew angle indicates that the second
• Inclination angle with respect to the radial direction in the direction of rotation opens.
• the second skew angle is particularly chosen so that it is directed substantially parallel to the flow generated by the stirring body. As a result, a deflection of the flow is avoided. This can further improve the radial range of the flow.
• the lower flow-guiding means is an annular disc extending substantially parallel to the plane.
• a breakthrough provided in the center of the annular disk allows passage of the liquid medium flowing back at the bottom of the tank into the area of action of the stirring body and thus its acceleration in a radially outward-pointing direction.
• support elements for supporting on a bottom of the basin may be provided, such that a further annular gap is formed between the bottom and the lower fluid.
• the further annular gap allows the substantially unimpeded formation of the return flow in a region below the stirring body.
• the support means may essentially be radially extending further walls. Such other walls set the return flow against a low flow resistance and thus contribute to the formation of a flow with an improved range at.
• the negative sign in front of the amount of the aforementioned third skew angle again indicates that it opens with respect to the radial direction opposite to the direction of rotation of the stirring body.
• the proposed skew of the second inclined walls is chosen in particular so that it runs parallel to the direction of a ground-level return flow. This avoids a deflection of the return flow. As a result, the return flow is counteracted with the least possible resistance, which in turn allows the radial range of the flow to be increased.
• a gap width of the annular gap running essentially parallel to the shaft widens toward the peripheral edge of the stirring body.
• the annular gap forms an annular nozzle with which the flow directed away from the peripheral edge of the stirring body is guided not only in a plane substantially parallel to the pelvic floor, but also accelerated in this plane. This again contributes significantly to the improvement of the radial range of the flow.
• the transport ribs can bend towards the peripheral edge from an approximately radial direction in an opposite to the direction of rotation directed approximately tangential direction. Further, they may extend only in an outer radial portion of the upper side. In this embodiment, one of Peripheral edge of the stirring body directed away flow can be generated at a particularly high speed.
• a plurality of substantially radially extending shear ribs are provided on a further underside opposite the upper side.
• a height of the shear ribs may increase towards the peripheral edge of the stirring body.
• Such shear ribs serve to distribute air, which can be supplied via an air supply line in the region below the stirring body. This can do that
• Stirrer surrounding liquid medium are not only efficiently transported with a high reach in a radial direction, but it can also be mixed with the finest air bubbles.
• 1 is a partial cross-sectional view of a stirring device
• FIG. 2 is a complete cross-sectional view of the stirring device of FIG. 1,
• Fig. 3 is a perspective view of the stirring device
• Fig. 4 is a plan view of another stirring device.
• Fig. 1 shows a side view of a hyperboloid-like stirring body 1, which is fixed to a shaft 2.
• a radially outer portion transport ribs 3 which extend to a peripheral edge UM.
• the transport ribs 3 initially run in a substantially radial direction and then bend counter to a direction of rotation R in an in Substantial tangential direction.
• Shear ribs 4 are provided on an underside U in the vicinity of the peripheral edge UM, the height of which increases in a radially outward-pointing direction.
• the stirring body 1 is formed from a hyperboloid-shaped stirring body wall 5. He therefore has on its underside U a funnel-like recess 6.
• the peripheral edge UM of the stirring body 1 is surrounded by a flow guiding device 7.
• the flow guiding device 7 consists of a lower annular disc 8 and an annular disk-like flow guide element 9 arranged above it, which is held at a distance from the annular disc 8 by means of radially extending walls 10. Between the annular disc 8 and the flow guide 9, an annular gap 11 is formed, which surrounds the peripheral edge UM.
• the flow guiding element 9 is bent upward in a direction pointing toward the shaft 2, so that the annular gap 11 widens in a direction towards the peripheral edge UM.
• the annular disc 8 is over more walls
• the function of the stirring device is the following:
• the return flow RS which is also directed essentially parallel to the bottom B, enters the flow guiding device 7 through the lower annular gap 13 and is then deflected by the action of the stirring body 1 in order to emerge again from the annular gap 11 with the flow S.
• air supply line of the recess 6 air can be supplied.
• the air supply line can extend substantially parallel to the bottom B and bend below the shaft 2 in the direction of the recess 6.
• the medium flowing back according to the return flow RS can be mixed with the supplied air at the exit through the annular gap 11 by means of the shear ribs 4. It then passes through the annular gap 11, a liquid medium containing finest air bubbles.
• the flow S and the return flow RS are guided in parallel planes lying one above the other. This reduces interactions between the two flows S, RS. A radial range of the flow S and thus the efficiency of the stirring device are improved.
• Fig. 4 shows a plan view of another stirring device.
• the reference character ⁇ denotes a first skew angle. net, which is formed between a portion of the transport ribs 3 in the region of the peripheral edge UM and a radial direction RR.
• the first skew angle ⁇ is in a range of -30 ° to -90 °, here about at -45 °.
• the further stirring device differs from the stirring device shown in FIGS. 1 to 3 essentially by an oblique position of the walls 5 and of the further walls 12.
• First oblique walls 10a are indicated in FIG. 4 by long broken lines. They connect the flow guide 9 with the washer 8 arranged underneath.
• the horizontally extending first inclined walls 10a form with a radial direction RR a second skew angle ⁇ of + 30 ° to + 90 °, in this case approximately + 45 °.
• Second inclined walls 12a support the annular disc 8 with respect to the bottom B from.
• the also horizontally arranged second inclined walls 12a form with the radial direction RR a third skew angle Y in the range of -30 ° to -90 °, here about from -45 °.
• the first oblique walls 10a extend approximately perpendicular to the second oblique walls 12a.
• the flow S generated by the stirring body 1 runs approximately parallel to the first inclined walls 10a.
• the return flow RS runs approximately parallel to the second inclined walls 12a.
• first inclined walls 10a are not arranged parallel to one another.
• An annular gap section formed by the first inclined walls 10a widens in the radial direction.
• the velocity of the flow through the annular gap portion decreases in the radial direction.
• an auxiliary wall 10b may be provided, which parallel to the first inclined wall 10a arranged opposite to the direction of rotation R runs and with the next first inclined wall 10a near the peripheral edge UM has a common edge.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mixers Of The Rotary Stirring Type (AREA)
• Excavating Of Shafts Or Tunnels (AREA)
• Treatment Of Sludge (AREA)

Priority Applications (10)

Applications Claiming Priority (2)

Publications (1)

Family

ID=39926580

Family Applications (1)

Country Status (13)

Cited By (2)

Families Citing this family (8)

Citations (6)

Family Cites Families (23)

• 2008
  • 2008-07-18 JP JP2010519353A patent/JP5307812B2/ja not_active Expired - Fee Related
  • 2008-07-18 US US12/452,964 patent/US20100196165A1/en not_active Abandoned
  • 2008-07-18 EP EP08784897A patent/EP2175973B1/de not_active Not-in-force
  • 2008-07-18 ES ES08784897T patent/ES2366873T3/es active Active
  • 2008-07-18 DK DK08784897.4T patent/DK2175973T3/da active
  • 2008-07-18 AT AT08784897T patent/ATE510613T1/de active
  • 2008-07-18 WO PCT/EP2008/005923 patent/WO2009018915A1/de active Application Filing
  • 2008-07-18 BR BRPI0814951A patent/BRPI0814951B1/pt not_active IP Right Cessation
  • 2008-07-18 CN CN2008801026232A patent/CN101778665B/zh active Active
  • 2008-07-18 PL PL08784897T patent/PL2175973T3/pl unknown
• 2010
  • 2010-01-27 ZA ZA201000605A patent/ZA201000605B/xx unknown
  • 2010-01-28 IL IL203596A patent/IL203596A/en active IP Right Grant
  • 2010-02-08 EG EG2010020204A patent/EG25611A/xx active

Patent Citations (6)

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