EP0642833B1 - Method of separating solids by means of flotation - Google Patents
Method of separating solids by means of flotation Download PDFInfo
- Publication number
- EP0642833B1 EP0642833B1 EP94110775A EP94110775A EP0642833B1 EP 0642833 B1 EP0642833 B1 EP 0642833B1 EP 94110775 A EP94110775 A EP 94110775A EP 94110775 A EP94110775 A EP 94110775A EP 0642833 B1 EP0642833 B1 EP 0642833B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- flotation
- suspension
- air
- vessel
- clarification chamber
- 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.)
- Expired - Lifetime
Links
- 238000005188 flotation Methods 0.000 title claims description 63
- 238000000034 method Methods 0.000 title claims description 30
- 239000007787 solid Substances 0.000 title claims description 5
- 239000000725 suspension Substances 0.000 claims description 32
- 239000006260 foam Substances 0.000 claims description 16
- 238000005352 clarification Methods 0.000 claims description 13
- 239000000126 substance Substances 0.000 claims description 2
- 238000000926 separation method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000010802 sludge Substances 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000005273 aeration Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000002761 deinking Substances 0.000 description 1
- 230000005686 electrostatic field Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000010893 paper waste Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/14—Flotation machines
- B03D1/1431—Dissolved air flotation machines
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/14—Flotation machines
- B03D1/1418—Flotation machines using centrifugal forces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/14—Flotation machines
- B03D1/1493—Flotation machines with means for establishing a specified flow pattern
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
- B04C3/00—Apparatus in which the axial direction of the vortex flow following a screw-thread type line remains unchanged ; Devices in which one of the two discharge ducts returns centrally through the vortex chamber, a reverse-flow vortex being prevented by bulkheads in the central discharge duct
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
- B04C3/00—Apparatus in which the axial direction of the vortex flow following a screw-thread type line remains unchanged ; Devices in which one of the two discharge ducts returns centrally through the vortex chamber, a reverse-flow vortex being prevented by bulkheads in the central discharge duct
- B04C3/06—Construction of inlets or outlets to the vortex chamber
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/14—Flotation machines
- B03D1/1443—Feed or discharge mechanisms for flotation tanks
- B03D1/1475—Flotation tanks having means for discharging the pulp, e.g. as a bleed stream
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/14—Flotation machines
- B03D1/24—Pneumatic
- B03D1/245—Injecting gas through perforated or porous area
Definitions
- the invention relates to a method for separating solids by Flotation from a suspension according to the preamble of claim 1 and to one Device for performing the method.
- Methods of the type mentioned are used to get out of a suspension at least to excrete a portion of the solid particles suspended therein. The goal this can be done either by removing unwanted components of the suspension or the clarification of polluted wastewater.
- one Flotation is a foam or floating sludge containing the substances to be separated educated.
- a typical application for the use of such a method is Preparation of a suspension made of printed waste paper, in which the Ink particles are already detached from the fibers, making them selective let float (deinking flotation).
- EP-A-0 198 737 shows a flotation device for a process of specified type, in which the suspension during flotation is a Performs rotational movement.
- the devices shown in this publication however, contain annular partitions through which the rotating suspension during the flotation is slowed in its axial movement and guided radially inwards. By this measure and mostly also in that a deflection of the Suspension, viewed axially, is made, the reinforcement takes place Centrifugal fields, however, optimal flotation is not possible.
- Another flotation device is known from DE-A-33 06 600, which already use the acceleration field caused by the rotational movement of the suspension can.
- the flotation foam is there from an overhead pipe Flotation device removed while the cleaned suspension flows off at the bottom.
- Such current routing is also common with hydrocyclones. she leads to a disproportionate increase in centrifugal acceleration Center of the container in the form of a potential vortex.
- WO-A-91/15302 describes a variety of different cylindrical Separating devices shown and described, in which with the help of magnets or electrostatic fields a separation process is to be applied. Doing so only the supplementary application of flotation processes in such devices mentioned, whereby their effect seems insignificant. A highly effective one Flotation processes are not shown in this document.
- the invention had for its object to provide a method which Use of a centrifugal field an even better separation of the suspended Solid particles or the use of relatively compact flotation devices or both allowed.
- the method according to the invention takes place in the flotation space - viewed axially - no change in the direction of foam transport. This will target the Avoid formation of a potential vortex.
- the method is as follows carried out that a transport of the floated shares substantially parallel to Rotation axis 5 and in the same direction as that of the superimposed movement 4 (Arrows 6).
- the floated portions collected in this way are removed from clarification room 1 dissipated, indicated here by the arrows 7, usually together with free, from the air escaping from the suspension foam, arrow 10.
- For flotation required air is either added to the fabric at the inlet, arrow 9, and / or through Openings in the clarification room 1 during the actual flotation, arrows 9 '.
- Fig. 2 shows a simplified section through a flotation tank 12 with which the Procedure can be performed.
- An inlet 13 and an outlet 14 can be seen (shown offset here) and the sludge pipe 15.
- 13 a turbulence generating device 17 may be present, here as a step diffuser formed in the air in the vicinity of the step jump through an air line 16th is pumped in or sucked in.
- step diffusers one above the other in the vertical direction, in the radial direction Direction only one intended.
- Turbulence generation with the help of step diffusers also when entering flotation machines, is known per se, but offers in Connection with the other features of the method according to the invention special advantages. This is related to the task, in the smallest possible space to achieve the best possible flotation effect. Therefore, controlled micro-vertebrae and a force field increased by rotational movement of great benefit.
- Fig. 3 shows the apparatus of Fig. 2 as a view from above and in particular does tangential inlet 13 and outlet 14 visible.
- FIG. 4 shows a slightly conical rather than a cylindrical one Flotation tank 12 '.
- a measure can Rotational motion can be accelerated without adding more energy, which about friction losses could be compensated. It can also be assumed that the total volume of the air flowing out into the center of the flotation tank Suspension becomes lower.
- Fig. 5 shows part of another suitable for performing the method Flotation device, namely the area of the sludge pipe 15 '.
- This is as concentric double tube formed so that two different fractions of im central part of the flotation container can be removed. It can be particularly advantageous to concentrate as much as possible Foam fraction 21 separately from a foam / suspension mixed fraction 22 deduct. A further separation step would then result from the latter To win usable things, e.g. unintentionally removed paper fibers.
- Such a module unit can essentially consist of flotation tanks, as already described.
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Biotechnology (AREA)
- Physical Water Treatments (AREA)
Description
Die Erfindung bezieht sich auf ein Verfahren zur Abtrennung von Feststoffen durch
Flotation aus einer Suspension gemäß Oberbegriff des Anspruchs 1 sowie auf eine
Vorrichtung zur Durchführung des Verfahrens.The invention relates to a method for separating solids by
Flotation from a suspension according to the preamble of
Verfahren der genannten Art werden verwendet, um aus einer Suspension zumindest einen Teil der darin suspendierten Feststoffteilchen auszuscheiden. Die Zielsetzung hierzu kann entweder die Entfernung von unerwünschten Bestandteilen der Suspension oder die Klarung von verschmutztem Abwasser sein. Bekanntlich wird bei einer Flotation ein die auszuscheidenden Stoffe enthaltender Schaum oder Schwimm-Schlamm gebildet.Methods of the type mentioned are used to get out of a suspension at least to excrete a portion of the solid particles suspended therein. The goal this can be done either by removing unwanted components of the suspension or the clarification of polluted wastewater. As is well known, one Flotation is a foam or floating sludge containing the substances to be separated educated.
Ein typischer Anwendungsfall für die Verwendung eines derartigen Verfahrens ist die Aufbereitung von einer aus bedrucktem Altpapier hergestellten Suspension, in der die Druckfarben-Partikel bereits von den Fasern abgelöst sind, so daß sie sich selektiv ausflotieren lassen (Deinking-Flotation).A typical application for the use of such a method is Preparation of a suspension made of printed waste paper, in which the Ink particles are already detached from the fibers, making them selective let float (deinking flotation).
Die EP-A-0 198 737 zeigt eine Flotationsvorrichtung für ein Verfahren der angegebenen Art, in der also die Suspension wahrend der Flotation eine Rotationsbewegung ausführt. Die in dieser Publikation gezeigten Vorrichtungen enthalten jedoch ringförmige Trennwände, durch die die rotierende Suspension während der Flotation in ihrer Axialbewegung gebremst und radial nach innen geführt wird. Durch diese Maßnahme und zumeist auch dadurch, daß zusätzlich eine Umlenkung der Suspension, axial betrachtet, vorgenommen wird, erfolgt zwar eine Verstärkung der Zentrifugalfelder, eine optimale Flotation ist so jedoch nicht möglich.EP-A-0 198 737 shows a flotation device for a process of specified type, in which the suspension during flotation is a Performs rotational movement. The devices shown in this publication however, contain annular partitions through which the rotating suspension during the flotation is slowed in its axial movement and guided radially inwards. By this measure and mostly also in that a deflection of the Suspension, viewed axially, is made, the reinforcement takes place Centrifugal fields, however, optimal flotation is not possible.
Aus der DE-A-33 06 600 ist eine weitere Flotationsvorrichtung bekannt, die bereits das durch Rotationsbewegung der Suspension verursachte Beschleunigungsfeld benutzen kann. Der Flotationsschaum wird dort durch ein obenliegendes Rohr aus der Flotationsvorrichtung entfernt, während die gereinigte Suspension unten abfließt. Das bedeutet eine Aufteilung der einfließenden Strömung in, axial gesehen, entgegengesetzt gerichtete Teilströme. Eine solche Stromführung ist auch bei Hydrozyklonen üblich. Sie führt zu einem überproportionalen Ansteigen der Zentrifugalbeschleunigung zur Behältermitte hin in Form eines Potentialwirbels.Another flotation device is known from DE-A-33 06 600, which already use the acceleration field caused by the rotational movement of the suspension can. The flotation foam is there from an overhead pipe Flotation device removed while the cleaned suspension flows off at the bottom. The means dividing the inflowing flow into, viewed axially, opposite directed partial flows. Such current routing is also common with hydrocyclones. she leads to a disproportionate increase in centrifugal acceleration Center of the container in the form of a potential vortex.
In der WO-A-91/15302 wird eine Vielzahl von verschiedenen zylindrischen Trennvorrichtungen gezeigt und beschrieben, bei denen mit Hilfe von Magneten oder elektrostatischen Feldern ein Trennverfahren angewandt werden soll. Dabei wird lediglich die ergänzende Anwendung von Flotationsverfahren in derartigen Geräten erwähnt, wobei ihre Wirkung unbedeutend erscheint. Ein hochwirksames Flotationsverfahren wird in dieser Schrift nicht dargestellt.WO-A-91/15302 describes a variety of different cylindrical Separating devices shown and described, in which with the help of magnets or electrostatic fields a separation process is to be applied. Doing so only the supplementary application of flotation processes in such devices mentioned, whereby their effect seems insignificant. A highly effective one Flotation processes are not shown in this document.
Der Erfindung lag die Aufgabe zugrunde, ein Verfahren zu schaffen, welches unter Ausnutzung von einem zentrifugalfeld eine noch bessere Abtrennung den suspendierten Feststoffleilchen oder die Verwendung relativ kompakter Flotationsvorrichtungen oder beides gestattet.The invention had for its object to provide a method which Use of a centrifugal field an even better separation of the suspended Solid particles or the use of relatively compact flotation devices or both allowed.
Diese Aufgaben werden durch die im Kennzeichen des Anspruchs 1 genannten Merkmale
gelöst.These tasks are achieved by the features mentioned in the characterizing part of
In den Unteransprüchen werden besonders vorteilhafte Ausführungsformen des Verfahrens sowie Vorrichtungen zur Durchführung des Verfahrens beschrieben.Particularly advantageous embodiments of the Process and devices for performing the method described.
Durch das erfindungsgemäße Verfahren erfolgt im Flotationsraum - axial betrachtet - keine Umlenkung der Transportrichtung des Schaumes. Dadurch wird gezielt die Ausbildung eines Potentialwirbels vermieden.The method according to the invention takes place in the flotation space - viewed axially - no change in the direction of foam transport. This will target the Avoid formation of a potential vortex.
In dem Bereich, wo sich der flotierte Stoff sammelt, wird so eine ungestörte Axialströmung des Schaumes in Richtung zum Schaumaustrag ermöglicht. Es können kaum noch störende Wirbel im Bereich der Trennung von Schaum und Suspension entstehen. Dieser Bereich ist besonders kritisch für die Reinheit des Flotations-Gutstoffes.In the area where the floating material collects, it becomes undisturbed Axial flow of the foam in the direction of the foam discharge enables. It can hardly any disturbing eddies in the area of the separation of foam and suspension arise. This area is particularly critical for the purity of the Flotation acceptor.
Die Erfindung wird erläutert anhand von Zeichnungen. Dabei zeigen:
- Fig. 1
- schematisch die wichtigsten Verfahrensschritte;
- Fig. 2
- schematisch eine geschnitten dargestellte mögliche Vorrichtung zur Durchführung des Verfahrens;
- Fig. 3
- eine Aufsicht des in Fig. 2 gezeigten Gegenstandes;
- Fig. 4
- eine weitere Vorrichtung zur Durchführung des Verfahrens;
- Fig. 5
- einen variierten Schaumaustrag.
- Fig. 1
- schematically the most important process steps;
- Fig. 2
- schematically shows a possible device shown in section for performing the method;
- Fig. 3
- a plan view of the object shown in Fig. 2;
- Fig. 4
- another device for performing the method;
- Fig. 5
- a varied foam discharge.
Fig. 1 zeigt mit gestrichelten Linien einen Klärraum 1, in den die Suspension 2
zugeführt wird. Die Suspension führt anschließend eine Rotationsbewegung, angedeutet
durch den Pfeil 3 um die Achse 5 aus. Der Rotationsbewegung 3 wird eine weitere
Bewegung, dargestellt durch die Pfeile 4, überlagert, welche im wesentlichen parallel
zur Rotationsachse 5 verlaufen. Infolge des bekannten Mechanismus bei der Flotation
steigen die flotierten Stoffe zusammen mit Luftblasen entgegen der Wirkung eines
Schwerefeldes auf. Da das Schwerefeld als Zentrifugalfeld infolge der Rotationsbewegung
3 entsteht, bewegen sich die flotierten Anteile radial nach innen. Im radial inneren
Bereich des Klärraumes 1 findet also die Ansammlung des Flotationsschaumes statt,
wobei sich eine mehr oder weniger scharfe Grenze 8 zwischen dem Flotationsschaum und
der daraus ausgetretenen Luft bildet. Erfindungsgemäß wird das Verfahren so
durchgeführt, daß ein Transport der flotierten Anteile im wesentlichen parallel zur
Rotationsachse 5 und in derselben Richtung wie die der überlagerten Bewegung 4 erfolgt
(Pfeile 6). Die so gesammelten flotierten Anteile werden aus dem Klärraum 1
abgeführt, hier durch die Pfeile 7 angedeutet, in der Regel zusammen mit freier, aus
dem Suspensionsschaum ausgetretenen Luft, Pfeil 10. Der Teil der Suspension, aus dem
die flotierten Anteile entfernt sind, tritt aus dem Klärraum aus, Pfeil 11. Zur Flotation
benötigte Luft wird entweder dem Stoff beim Einlauf zugegeben, Pfeil 9, und/oder durch
Öffnungen im Klärraum 1 während der eigentlichen Flotation, Pfeile 9'.1 shows with a broken line a
Fig. 2 zeigt vereinfacht den Schnitt durch einen Flotationsbehälter 12, mit dem das
Verfahren ausgeführt werden kann. Man erkennt einen Einlauf 13 und einen Auslauf 14
(hier versetzt gezeichnet) sowie das Schlammrohr 15. Mit Vorteil kann im Einlauf 13
eine Turbulenzerzeugungsvorrichtung 17 vorhanden sein, hier als Stufendiffusor
ausgebildet, in den in der Nähe des Stufensprunges Luft durch eine Luftleitung 16
zugepumpt oder angesaugt wird. Um einen möglichst breiten flachen Strahl zu erzeugen,
sind in senkrechter Richtung mehrere Stufendiffusoren übereinander, in radialer
Richtung nur einer vorgesehen. Die Turbulenzerzeugung mit Hilfe von Stufendiffusoren,
auch beim Einlauf in Flotationsapparate, ist zwar an sich bekannt, bietet aber im
Zusammenhang mit den übrigen Merkmalen des erfindungsgemäßen Verfahrens
besondere Vorteile. Das hängt mit der Aufgabe zusammen, auf möglichst kleinem Raum
eine möglichst gute Flotationswirkung zu erzielen. Daher sind kontrollierte Mikro-Wirbel
und ein durch Rotationsbewegung erhöhtes Kraftfeld von großem Nutzen.Fig. 2 shows a simplified section through a
Fig. 3 zeigt den Apparat der Fig. 2 als Ansicht von oben und macht insbesondere den
tangentialen Einlauf 13 und Auslauf 14 sichtbar.Fig. 3 shows the apparatus of Fig. 2 as a view from above and in particular does
Fig. 4 zeigt im Gegensatz zu Fig. 2 keinen zylindrischen sondern einen leicht konischen
Flotationsbehälter 12'. Bekanntlich kann durch eine solche Maßnahme die
Rotationsbewegung beschleunigt werden, ohne weitere Energie zuzuführen, wodurch
etwa Reibungsverluste ausgeglichen werden könnten. Ferner ist davon auszugehen, daß
durch ausgeströmte Luft in die Mitte des Flotationsbehälters das Gesamtvolumen der
Suspension geringer wird. Als weitere Variationsmöglichkeit, nicht unbedingt an die
konische Form des Flotationsbehälters gebunden, ist die Belüftung der Suspension
während der Flotation durch einen Luftkasten 18, an den ein Luftanschluß 19
angebracht ist. Natürlich müssen in so einem Falle geeignete Schritte unternommen
werden, um im Bereich der Wandung 20 einen Eintritt der Luft in die Suspension zu
ermöglichen, z.B. durch poröse oder gelochte Ausführungen.In contrast to FIG. 2, FIG. 4 shows a slightly conical rather than a cylindrical one
Flotation tank 12 '. As you know, such a measure can
Rotational motion can be accelerated without adding more energy, which
about friction losses could be compensated. It can also be assumed that
the total volume of the air flowing out into the center of the flotation tank
Suspension becomes lower. As a further variation option, not necessarily to the
Tied to the conical shape of the flotation tank is the aeration of the suspension
during the flotation through an
Fig. 5 zeigt einen Teil einer weiteren zur Durchführung des Verfahrens geeigneten
Flotationsvorrichtung, und zwar den Bereich des Schlammrohres 15'. Dieses ist als
konzentrisches Doppelrohr ausgebildet, so daß zwei verschiedene Fraktionen von im
mittleren Teil des Flotationsbehälters angesammeltem Stoff abgezogen werden können.
Es kann nämlich von besonderem Vorteil sein, eine möglichst konzentrierte
Schaumfraktion 21 separat von einer Schaum/Suspensions-Mischfraktion 22
abzuziehen. Aus Letzterer wäre dann durch einen weiteren Trennschritt noch
Verwertbares zu gewinnen, wie z.B. unbeabsichtigt abgeführte Papierfasern.Fig. 5 shows part of another suitable for performing the method
Flotation device, namely the area of the sludge pipe 15 '. This is as
concentric double tube formed so that two different fractions of im
central part of the flotation container can be removed.
It can be particularly advantageous to concentrate as much as
Die Strömungsführung in dem Sinne, daß am oberen Teil des Flotationsbehälters eingeführt und am unteren Teil sowohl der Schaum als auch die gereinigte Suspension abgeführt wird, ist nicht zwingend. Auch eine gerade umgekehrte Strömungsführung ist denkbar und in besonderen Fällen von Vorteil.The flow in the sense that at the top of the flotation tank introduced and at the bottom both the foam and the cleaned suspension is dissipated is not mandatory. A straight reverse flow is also conceivable and advantageous in special cases.
Es ist ohne weiteres vorstellbar, eine Anzahl von Flotationsbehältern zu Modulen zusammenzusetzen, wodurch sich die gestellte Aufgabe einer kompakten Anordnung der gesamten Flotationsanlage noch besser lösen läßt. Eine solche Moduleneinheit kann im wesentlichen aus Flotationsbehältern, wie bereits beschrieben, bestehen.It is easily conceivable to add a number of flotation containers to modules put together, which is the task of a compact arrangement of the entire flotation system can be solved even better. Such a module unit can essentially consist of flotation tanks, as already described.
Claims (20)
- A method for separating off solids from a suspension by flotation in a substantially cylindrical clarification chamber (1), the suspension during the flotation performing a rotational movement (3) on which an additional movement (4) is superposed which extends substantially in one direction of the axis of rotation (5), the floated contents moving radially inwards and furthermore substantially likewise in the direction of the axis of rotation (5) and the discharge of the suspension (11) from the clarification chamber (1) being effected tangentially,
characterised in that the suspension rotates during the flotation inside the cylindrical clarification chamber (1), without being carried radially inwards. - A method according to Claim 1, characterised in that microturbulences are produced in the suspension (2) which is supplied, as is known per se, close to the inlet into the clarification chamber (1).
- A method according to Claim 1, characterised in that the inflow of the suspension (2) is effected tangentially.
- A method according to Claim 1 or 2, characterised in that air (9) required for flotation reaches the clarification chamber (1) together with the suspension.
- A method according to Claims 2 and 4, characterised in that air (9) required for flotation is admixed in the region of the microturbulences.
- A method according to Claim 1 or 2, characterised in that air (9') required for flotation is added to the suspension in the clarification chamber (1).
- A method according to Claim 1 or 2, characterised in that the suspension to be floated (2) contains dissolved air, and air bubbles required for flotation are produced by a pressure drop in the suspension.
- A method according to Claim 1 or 2, characterised in that floated contents are removed from the clarification chamber in a plurality of fractions (21, 22).
- A method according to Claim 8, characterised in that one fraction (22) contains substances which are separated off in a subsequent process step.
- A flotation apparatus for performing the method according to one of the preceding claims, having a substantially rotationally symmetrical flotation vessel (12, 12') which is vertical in operation, at least one tangential inlet (13) for the suspension which is to be supplied, means (16, 17, 18, 19) for producing and distributing air bubbles, at least one tangential outlet (14) for the suspension which is to be removed and also at least one foam pipe (15, 15') in the central region of the flotation vessel (12, 12') for the floated contents which, viewed axially, is located on the side of the flotation vessel (12, 12') on which the outlet (14) is also located,
characterised in that the flotation vessel (12, 12') is free of radially extending intermediate walls between the inlet (13) and outlet (14). - A flotation apparatus according to Claim 10, characterised in that the flotation vessel (12, 12') is cylindrical.
- A flotation apparatus according to Claim 10, characterized in that the flotation vessel (12, 12') tapers towards the outlet.
- A flotation apparatus according to one of Claims 10 to 12, characterised in that a turbulence generator (17) is located in the region of the inlet (13).
- A flotation apparatus according to Claim 13, characterized in that the turbulence generator (17) is a step diffusor which widens discontinuously.
- A flotation apparatus according to Claim 13 or 14, characterized in that air required for flotation can be supplied to the turbulence generator (17).
- A flotation apparatus according to one of Claims 10 to 15, characterized in that air required for flotation can be introduced from an air box (18) radially into the flotation vessel (12, 12') through a permeable wall section (20) thereof.
- A flotation apparatus according to one of Claims 10 to 16, characterized in that air bubbles required for flotation can be generated with the aid of a choke located before or in the inlet (13) by reducing pressure in the suspension.
- A flotation apparatus according to one of Claims 10 to 16, characterized in that the ratio of the maximum internal diameter of the foam pipe (15, 15') to the maximum internal diameter of the flotation vessel (12, 12') is greater than 0.6.
- A flotation apparatus according to one of Claims 10 to 18, characterized in that the foam pipe (15') has a plurality of, in particular two, concentric pipes which substantially coincide axially, so that a plurality of, in particular two, different fractions with floated pulp can be discharged.
- A flotation apparatus according to Claim 19, characterized in that a tangential outlet consists of at least one, in particular the radially outer one, of the spaces formed by the concentric pipes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4330635A DE4330635C2 (en) | 1993-09-10 | 1993-09-10 | Process for the separation of solids by flotation and flotation device |
| DE4330635 | 1993-09-10 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0642833A1 EP0642833A1 (en) | 1995-03-15 |
| EP0642833B1 true EP0642833B1 (en) | 1998-09-30 |
Family
ID=6497311
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP94110775A Expired - Lifetime EP0642833B1 (en) | 1993-09-10 | 1994-07-12 | Method of separating solids by means of flotation |
Country Status (3)
| Country | Link |
|---|---|
| US (2) | US5690812A (en) |
| EP (1) | EP0642833B1 (en) |
| DE (1) | DE4330635C2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0873194A4 (en) * | 1995-11-14 | 1999-09-29 | Automatic Control Technology I | Vortex system for separating particles from a liquid stream |
| DE19618529B4 (en) * | 1996-05-08 | 2005-12-22 | Papiertechnische Stiftung (Pts) | Use of a rotationally symmetrical cell and apparatus for substance mixture separation in the preparation and cleaning of printed wastepaper |
| DE19728394A1 (en) * | 1997-07-03 | 1999-01-07 | Voith Sulzer Stoffaufbereitung | Cleaning fibre suspensions |
| DE19835434C2 (en) * | 1998-08-05 | 2000-08-17 | Wolfgang Reuschl | Apparatus and method for the sterile separation of solid particles from suspensions by means of pneumatic flotation in continuous operation |
| US20030194755A1 (en) * | 2001-04-27 | 2003-10-16 | Genoptix, Inc. | Early detection of apoptotic events and apoptosis using optophoretic analysis |
| CA2677666C (en) * | 2007-02-09 | 2015-12-15 | Environmental Stewardship Solutions, Llc. | Method for recovering suspended solids from residual effluents |
| GB2461874B (en) * | 2008-07-14 | 2012-11-21 | Caltec Ltd | Separation system and method |
Family Cites Families (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3557956A (en) * | 1970-01-28 | 1971-01-26 | Bergstrom Paper Co | Method for de-inking and removal of certain contaminants from reclaimed paper stock |
| DE2738782C2 (en) * | 1977-08-27 | 1979-07-12 | J.M. Voith Gmbh, 7920 Heidenheim | Flotation device for removing printing ink |
| US4094783A (en) * | 1977-09-29 | 1978-06-13 | Jackson George F | Centrifugal flotation separator |
| US4399027A (en) * | 1979-11-15 | 1983-08-16 | University Of Utah Research Foundation | Flotation apparatus and method for achieving flotation in a centrifugal field |
| US4378289A (en) * | 1981-01-07 | 1983-03-29 | Hunter A Bruce | Method and apparatus for centrifugal separation |
| US4414112A (en) * | 1982-01-29 | 1983-11-08 | Recovery Technology Associates | Oil/water separator |
| CH658481A5 (en) * | 1983-02-18 | 1986-11-14 | Escher Wyss Gmbh | FLOTATION DEVICE FOR FLOTING FIBER FIBER SUSPENSION MADE FROM WASTE PAPER. |
| JPS60501995A (en) * | 1983-08-11 | 1985-11-21 | キヤロル，ノエル | Liquid separation method and device |
| AT387407B (en) * | 1984-01-09 | 1989-01-25 | Escher Wyss Gmbh | FLOTATION DEVICE FOR FLOTING FIBER FIBER SUSPENSION MADE FROM WASTE PAPER |
| FR2579638B1 (en) * | 1985-03-29 | 1988-09-02 | Lamort E & M | APPARATUS FOR INKING PAPER PULP |
| JPS6417726A (en) * | 1987-07-11 | 1989-01-20 | Canon Kk | Image reader |
| CA1328629C (en) * | 1987-09-05 | 1994-04-19 | Peter Gregory Michaluk | Separator |
| SU1558493A1 (en) * | 1987-12-18 | 1990-04-23 | Всесоюзный Научно-Исследовательский И Проектно-Конструкторский Институт Микробиологических Производств | Flotation apparatus |
| US4876016A (en) * | 1988-06-27 | 1989-10-24 | Amoco Corporation | Method of controlling the separation efficiency of a hydrocyclone |
| US5028318A (en) * | 1989-04-19 | 1991-07-02 | Aeroquip Corporation | Cyclonic system for separating debris particles from fluids |
| US4997549A (en) * | 1989-09-19 | 1991-03-05 | Advanced Processing Technologies, Inc. | Air-sparged hydrocyclone separator |
| US5224604A (en) * | 1990-04-11 | 1993-07-06 | Hydro Processing & Mining Ltd. | Apparatus and method for separation of wet and dry particles |
| DE4017446C2 (en) * | 1990-05-30 | 1995-02-23 | Escher Wyss Gmbh | Flotation deinking device |
| US5236090A (en) * | 1990-05-30 | 1993-08-17 | Sulzer-Escher Wyss Gmbh | Flotation-deinking-device |
| US5069751A (en) * | 1990-08-09 | 1991-12-03 | Kamyr, Inc. | Hydrocyclone deinking of paper during recycling |
| EP0618012B1 (en) * | 1993-04-02 | 1996-09-18 | J.M. Voith GmbH | Flotation device |
-
1993
- 1993-09-10 DE DE4330635A patent/DE4330635C2/en not_active Expired - Fee Related
-
1994
- 1994-07-12 EP EP94110775A patent/EP0642833B1/en not_active Expired - Lifetime
-
1995
- 1995-11-02 US US08/552,205 patent/US5690812A/en not_active Expired - Fee Related
-
1997
- 1997-04-30 US US08/841,618 patent/US5916446A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE4330635C2 (en) | 1996-07-11 |
| EP0642833A1 (en) | 1995-03-15 |
| US5690812A (en) | 1997-11-25 |
| US5916446A (en) | 1999-06-29 |
| DE4330635A1 (en) | 1995-03-16 |
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