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WO1995007149A1 - Separateur a air a force centrifuge - Google Patents

Separateur a air a force centrifuge Download PDF

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Publication number
WO1995007149A1
WO1995007149A1 PCT/AT1994/000126 AT9400126W WO9507149A1 WO 1995007149 A1 WO1995007149 A1 WO 1995007149A1 AT 9400126 W AT9400126 W AT 9400126W WO 9507149 A1 WO9507149 A1 WO 9507149A1
Authority
WO
WIPO (PCT)
Prior art keywords
classifying
rotor
outlet
centrifugal air
inlet
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.)
Ceased
Application number
PCT/AT1994/000126
Other languages
German (de)
English (en)
Inventor
Horst Thaler
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.)
PMT GESTEINSVERMAHLUNGSTECHNIK
Original Assignee
PMT GESTEINSVERMAHLUNGSTECHNIK
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 PMT GESTEINSVERMAHLUNGSTECHNIK filed Critical PMT GESTEINSVERMAHLUNGSTECHNIK
Publication of WO1995007149A1 publication Critical patent/WO1995007149A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B7/00—Selective separation of solid materials carried by, or dispersed in, gas currents
    • B07B7/08—Selective separation of solid materials carried by, or dispersed in, gas currents using centrifugal force
    • B07B7/083—Selective separation of solid materials carried by, or dispersed in, gas currents using centrifugal force generated by rotating vanes, discs, drums, or brushes

Definitions

  • the present invention relates to a centrifugal air classifier with a classifier housing, each having one or a common inlet for the classifying material and the classifying gas and an outlet for the coarse material, and with a drivable, cylindrical and hollow classifying rotor mounted in the classifier housing, over its circumference a multiplicity of axially parallel inlet gaps for the entry of the classifying material / classifying gas mixture is distributed and an outlet for the fine material axially adjoins one end thereof and is led out of the classifier housing.
  • An important indicator of the performance of a wind sifter is its discriminatory power, which can be defined, for example, as the residual fine material portion in the coarse material to the fine material portion of the feed material.
  • the selectivity depends on the observance of the separation limit in the wind sifter, which is the grain size above which the mass-dependent centrifugal force acting on the grain predominates and conveys it to the discharge of coarse material, and below which the drag force of the sight gas flow opposite to the centrifugal force predominates and entrains the grain to the fines outlet.
  • the centrifugal force is essentially dependent on the tangential speed of the flow, and the drag force of the flow on its radial speed. From the point of view of an essentially constant tangential speed, as given by the rotor to the flow near the circumference of the rotor, the separation limit therefore depends essentially on the radial speed of the flow.
  • the classifying rotor axis is vertical here, and the classifying material is placed on the top of a plate rotating with the classifying rotor and falls circumferentially into the vertical annular space around the classifying rotor, which is surrounded by the classifying gas supply spiral. give is.
  • the classifying gas is drawn off on the underside of the rotor interior.
  • this document proposes that the classifying gas supply spiral be arranged one above the other with independently adjustable ones
  • Subdivide 10 flaps provided channels, the upper channels are operated with a larger amount of visible gas than the lower.
  • this solution is structurally complex, on the other hand, it does not take into account the flow conditions in the rotor gap and in the rotor interior.
  • Radial velocities of the flow depend on the axial position under consideration. The radial velocity is greatest in the vicinity of the fines outlet and decreases towards the opposite end face. This effect loading • "rests on the self-adjusting over the -Axialerstreckung of the classifying rotor pressure gradient.
  • the invention aims to provide a centrifugal air classifier of the type mentioned, which has 35 improved selectivity. According to the invention, this goal is achieved in that the interior of the viewing rotor is subdivided into a plurality of axial sections which over Coaxial connection spigots running towards the said end face are connected to the common fine material outlet, the effective flow cross sections which are established via an axial section and the associated connection spigot being essentially the same size.
  • This measure allows approximately the same pressure ratios to be set in each axial section, so that only the pressure drops within a single axial section need to be taken into account, which are a fraction of the pressure drop across the entire axial extent of the classifying rotor, so that the maximum occurring change in the radial velocity of the flow is substantially less than in the construction according to the prior art.
  • the separation limit thus varies to a much lesser extent over the axial extent of the rotor, which decisively improves the separation efficiency of the air classifier. As a result, lower separation limits than previously can be achieved and maintained.
  • the optimization case i.e. equal pressure ratios in each axial section can be easily determined empirically.
  • the diameters of the connecting pieces are preferably selected so that the flow cross sections mentioned result.
  • the decoupling of the axial sections can be improved if they are separated from one another by annular partition walls.
  • the flow when the flow passes through an inlet gap, the flow also changes its radial speed via the radial extent of the inlet gap: for example, in the known view rotors composed of axially parallel rotor blades, the passage width increases at a certain axial position over the radial extent of the inlet gap towards the inside because the rotor blades are oriented radially and are therefore closer to the inner circumference of the classifying rotor than to the outer circumference.
  • the radial velocity of the flow increases as it passes through the inlet gap, as a result of which any coarse material that has entered the inlet gap is accelerated towards the inside towards the fine material outlet.
  • the radial increase in radial speed can also be interpreted as resulting in a large number of different separation limits over the radial extension of the inlet gap, which leads to a deterioration in the overall selectivity of the air classifier.
  • the passage width of the inlet gaps increase in the radially inward direction, as a result of which the radial velocity of the flow decreases over the radial extent of the inlet gaps.
  • the decrease in radial speed has the consequence that coarse material particles, which are at most drawn into the inlet gap, leave the outside again due to the decrease in the drag force, instead of being accelerated inwards, as is the case in the prior art the case is.
  • the selectivity of the air classifier is further increased.
  • the inlet gaps are formed between axially parallel rotor blades distributed over the circumference of the classifying rotor, they are tapered radially inwards, the side walls of the rotor blades lying rearward in the direction of rotation of the classifying rotor are essentially radially oriented, or in the case where the inlet gaps are milled into the jacket of the classifying rotor, the front side walls of the inlet gaps are oriented essentially radially in the direction of rotation of the classifying rotor.
  • FIG. 1 shows a centrifugal force air classifier in axial section
  • FIG. 2 shows a classifying rotor according to the prior art in axial section, over which the distribution of the radial speed is schematically plotted
  • FIG. 3 shows the classifying rotor according to the invention in axial section, over which the diagram schematically shows Distribution of the radial velocity is plotted
  • FIG. 4 shows the flow conditions in the inlet gap at a certain axial position using a radial section of a classifying rotor according to the prior art
  • FIG. 5 shows the flow conditions in the inlet gap at a certain axial position in the classifying rotor according to the invention in the same representation as in Fig. 4.
  • the centrifugal force air classifier has a drum-shaped classifier housing 1 which is provided on its upper side with an inlet 2 for the classifying gas / classifying material mixture. It is also possible to provide separate inlets on the circumference of the classifier housing 1 for the classifying material and the classifying gas.
  • a cylindrical, hollow classifying rotor 3 is rotatably supported coaxially via a shaft 4.
  • the sighting rotor 3 has a large number of axially parallel inlet gaps 5 distributed over its circumference, via which the sighting gas / sighting material mixture approaching the sighting rotor 3 in a spiral flow enters the inside of the sighting rotor.
  • At one end of the classifying rotor 3 there is an axial outlet 5 for the fine material.
  • the viewing rotor 3 is set in rotation by a drive, not shown in detail.
  • An outlet 7 for the coarse material is arranged on the underside of the classifier housing 1.
  • the classifying gas is either introduced into inlet 2 with pressure or withdrawn from outlet 6 under reduced pressure.
  • Each particle of the feed material is subject, on the one hand, to the centrifugal force in the vortex flow directed radially outwards and, on the other hand, to the drag force directed radially inwards of the flow.
  • Coarse material migrates to the periphery of the classifier housing and fine material to the center, where it is discharged via outlet 6
  • the inward drag force of the flow depends on the radial speed of the flow in the inlet gaps 5 of the classifying rotor 3. 2 shows these flow conditions in a classifying rotor of the prior art which has axially parallel inlet gaps which have a constant passage width over the axial extent of the classifying rotor 3. Because of the one-sided arrangement of the discharge, ie the fine material outlet 6, on an end face of the classifying rotor 3, a pressure drop occurs over the axial extent of the classifying rotor, which causes different radial intake speeds of the flow in the inlet columns 5. On the side of the fine material outlet 6, the radial speed of the flow is a maximum (V r max) and ⁇ 3 decreases towards the opposite side (V r min). The radial pull-in speed V r is schematically in FIG. 2 above the axial extent of the Visual rotor applied.
  • connection pieces 12, 13 and 14 are attached, which are coaxial to one another and to the shaft 4 of the classifying rotor 3 and open into the fine material outlet 6.
  • the last connector 14 is formed by the mouth of the fine material outlet 6 itself.
  • the effective flow cross-sections which are established via an axial section 7, 8 or 9 and the associated connecting piece 12, 13 or 14 are selected to be of the same size. This is achieved in particular by varying the diameters D, D2 and D3 of the connecting pieces and empirically determining the optimal coordination.
  • any number of axial sections can be provided, the variation of the radial speed v r over the axial extent of the classifying rotor becoming smaller the greater the number of axial sections.
  • the ring-shaped partitions 10, 11 are not absolutely necessary; with a suitable choice of the diameters Di, D2 or D3, they can also be omitted.
  • 4 and 5 deal with a further measure to improve the selectivity of the air classifier.
  • 4 shows the radial flow conditions at a specific axial position in the inlet gap 5.
  • rotor blades 15 are used in such a way that they are oriented radially so that the passage width d decreases in the radially inward direction (upper half of FIG. 4).
  • the radial velocity of the flow thus increases from v ra to v r i, which accelerates any coarse material particles that get into the inlet gap 5 towards the inside of the fine material outlet 6.
  • inlet gaps 5 are shown, which are milled into a jacket 17 of the classifying rotor 3 and whose passage width d remains constant in the radial direction. If the tangential speed is neglected, there is a uniform separation limit, but if this is taken into account, which decreases radially inwards, a decrease in the centrifugal force, what? an accelerated drawing in of any coarse particles that have occurred.
  • the passage width d of the inlet gap 5 increases over the radial extent of the inlet gap 5 (FIG. 5), so that the radial speed v r decreases, which compensates for the decrease in the centrifugal force and leads to the fact that Any coarse material particles that have entered the inlet gap 5 exit again to the outside.
  • Fig. 5 it can be seen that it is the side walls 16 of the rotor blades 15 lying rearward in the direction of rotation P of the classifying rotor 3 which are oriented essentially radially, whereas the opposite side walls run at an angle to the radial direction, i.e. the rejuvenation of the
  • the front walls 16 of the classing inlet 5 in the direction of rotation P of the classifying rotor 3 are accordingly oriented essentially radially.

Landscapes

  • Combined Means For Separation Of Solids (AREA)

Abstract

Séparateur à air à force centrifuge comprenant une enveloppe (1), présentant une entrée (2), soit distincte, pour le matériau à séparer et pour le gaz de séparation, soit commune, et une sortie (7) pour le matériau grossier, et un rotor-séparateur (3) cylindrique et creux, commandé, monté à l'intérieur de l'enveloppe et présentant, réparties sur sa périphérie, une pluralité de fentes d'admission (5) s'étendant parallèlement à l'axe du rotor, pour l'entrée du mélange matériau à séparer/gaz de séparation. A une extrémité dudit rotor est raccordée axialement une sortie (6) pour le matériau fin sortant de l'enveloppe. Le compartiment intérieur du rotor-séparateur (3) est subdivisé en plusieurs sections axiales (7, 8, 9) qui sont en communication avec la sortie commune de matériau fin (6), par l'intermédiaire de tubulures de raccordement (12, 13, 14) s'étendant coaxialement en direction de l'extrémité précitée, et les sections d'écoulement efficaces définies par chaque section axiale et la tubulure de raccordement associée sont de grosseur sensiblement égale.
PCT/AT1994/000126 1993-09-07 1994-09-07 Separateur a air a force centrifuge Ceased WO1995007149A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT180793A ATA180793A (de) 1993-09-07 1993-09-07 Zentrifugalkraft-windsichter
ATA1807/93 1993-09-07

Publications (1)

Publication Number Publication Date
WO1995007149A1 true WO1995007149A1 (fr) 1995-03-16

Family

ID=3521400

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AT1994/000126 Ceased WO1995007149A1 (fr) 1993-09-07 1994-09-07 Separateur a air a force centrifuge

Country Status (2)

Country Link
AT (1) ATA180793A (fr)
WO (1) WO1995007149A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2741286A1 (fr) * 1995-11-21 1997-05-23 Fcb Separateur a air a action centrifuge
EP0818249A1 (fr) * 1996-07-08 1998-01-14 PMT Gesteinsvermahlungstechnik Roue de triage pour séparateur pneumatique
WO2002026405A1 (fr) * 2000-09-07 2002-04-04 Roland Nied Separateur a air
RU2201811C2 (ru) * 2000-12-18 2003-04-10 Шишкин Сергей Федорович Центробежный воздушно-проходной классификатор

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2567777A1 (fr) * 1984-07-17 1986-01-24 Kloeckner Humboldt Deutz Ag Separateur pneumatique a cyclones pour la separation de matiere de granulometries differentes, notamment de ciment
DE8517621U1 (de) * 1985-06-15 1987-02-12 Klöckner-Humboldt-Deutz AG, 5000 Köln Streuwindsichter
DE3808023A1 (de) * 1988-03-10 1989-09-21 Krupp Polysius Ag Sichter
DE4135879A1 (de) * 1991-10-31 1993-05-06 Erich Netzsch Gmbh & Co Holding Kg, 8672 Selb, De Sichterrad

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2567777A1 (fr) * 1984-07-17 1986-01-24 Kloeckner Humboldt Deutz Ag Separateur pneumatique a cyclones pour la separation de matiere de granulometries differentes, notamment de ciment
DE8517621U1 (de) * 1985-06-15 1987-02-12 Klöckner-Humboldt-Deutz AG, 5000 Köln Streuwindsichter
DE3808023A1 (de) * 1988-03-10 1989-09-21 Krupp Polysius Ag Sichter
DE4135879A1 (de) * 1991-10-31 1993-05-06 Erich Netzsch Gmbh & Co Holding Kg, 8672 Selb, De Sichterrad

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2741286A1 (fr) * 1995-11-21 1997-05-23 Fcb Separateur a air a action centrifuge
WO1998046371A1 (fr) * 1995-11-21 1998-10-22 Fcb Separateur a air a action centrifuge
EP0818249A1 (fr) * 1996-07-08 1998-01-14 PMT Gesteinsvermahlungstechnik Roue de triage pour séparateur pneumatique
AT404234B (de) * 1996-07-08 1998-09-25 Pmt Gesteinsvermahlungstechnik Sichtrad für einen windsichter
US5957299A (en) * 1996-07-08 1999-09-28 Keuschnigg; Josef Separator wheel for an air separator
WO2002026405A1 (fr) * 2000-09-07 2002-04-04 Roland Nied Separateur a air
RU2201811C2 (ru) * 2000-12-18 2003-04-10 Шишкин Сергей Федорович Центробежный воздушно-проходной классификатор

Also Published As

Publication number Publication date
ATA180793A (de) 1994-12-15

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