EP0421188A1 - Pusher centrifuge - Google Patents

Pusher centrifuge Download PDF

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Publication number
EP0421188A1
EP0421188A1 EP90118002A EP90118002A EP0421188A1 EP 0421188 A1 EP0421188 A1 EP 0421188A1 EP 90118002 A EP90118002 A EP 90118002A EP 90118002 A EP90118002 A EP 90118002A EP 0421188 A1 EP0421188 A1 EP 0421188A1
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Prior art keywords
sieve
shaft
drums
ring
drum
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German (de)
French (fr)
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EP0421188B1 (en
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Bernd Hoppe
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Sulzer Escher Wyss AG
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Sulzer Escher Wyss AG
Escher Wyss AG
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B04CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04BCENTRIFUGES
    • B04B3/00Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering
    • B04B3/02Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering discharging solid particles from the bowl by means coaxial with the bowl axis and moving to and fro, i.e. push-type centrifuges

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  • the invention relates to a pusher centrifuge with at least two rotating sieve drums in a housing, in the interior of which centrifugal material can be fed at one end, and with at least one push ring between two sieve drums, which has an oscillating movement in the axial direction of the sieve drums for feeding the partially dewatered centrifugal material on the inside the following sieve drum in the direction of a solids outlet.
  • Such pusher centrifuges are known from CH 624 858 and CH 627 376 and are used for the continuous dewatering of centrifuged material, which is fed to the inner end of a centrifugal space via a feed pipe and is successively dewatered on the inside of the sieve drums.
  • the centrifuged material is moved in the axial direction oscillating movement of one or more push rings between adjacent sieve drums is gradually advanced towards a solids outlet, and at the same time non-dewatered centrifugal material is refilled in the vicinity of the push floor.
  • Such a pusher centrifuge has a plurality of sieve drums, two adjacent sieve drums each oscillating in the axial direction relative to one another and the edge of the inner sieve drum acting as a push ring.
  • the drum in a two-stage centrifuge, the drum, in a three-stage centrifuge, the moving floor and the second drum, and in a four-stage centrifuge, the first and third drums can oscillate in the axial direction.
  • Such a pusher centrifuge enables continuous dewatering of a centrifugal material, which is gradually dewatered in the centrifugal field from the centrifugal material inlet to the solids outlet during the feed on the inside of the sieve drums and reaches the solids outlet in a largely dewatered state, while the filtrate reaches the outside through the sieve drums penetrates and is discharged there.
  • a cake layering is formed on such push centrifuges on the sieve drums, which does not change significantly during the feed up to the discharge.
  • the solid cake formed becomes increasingly compact and therefore impermeable, so that the degree of drainage and the residual moisture of the discharged solid is not optimal for certain centrifugal goods and requires an extension of the dewatering time and an increased speed and a high energy consumption.
  • the invention has for its object to avoid the aforementioned disadvantages of the prior art and to create a push centrifuge with an increased degree of dewatering and lower residual moisture of the discharged solid, which is also suitable for dewatering particularly sensitive centrifugal material without the occurrence of grain breakage and abrasion.
  • this object is achieved in that a rotating device is provided, by means of which the thrust ring simultaneously executes a rotary movement about the axis direction of the sieve drums during the feed.
  • the rotary movement can also take place in an oscillating manner, so that turning back and loosening also take place when withdrawing, which can be effected in a simple manner with a screw guide of the corresponding sieve drum shafts against one another.
  • the relative rotary movement of the thrust ring can moreover be directed in the direction of rotation of the sieve drums, which can be advantageous in the case of fragile crystals, or else opposite to this direction of rotation.
  • the latter can be important for mixtures that are difficult to filter or low solids concentrations in the centrifuged material.
  • the pusher centrifuge shown in FIGS. 1 and 2 in perspective and in section has a centrifugal unit consisting of two rotatable sieve drums 1 and 2, a stationary centrifuge housing 3 surrounding it, a solid space 4 adjacent to the centrifugal unit at the outlet, and one close to the inner end of the centrifugal unit a moving floor 8 with a centrifugal material inlet 9 leading supply line 5 for the centrifuged material to be dewatered, a solids outlet 6, and a liquid space 7 for the ejected liquid.
  • the inner screening drum 1 is mounted on a shaft 10, by means of which it can be set in rotation at a certain speed. At the same time, the shaft 10 can be displaced in the axial direction A and, in addition to its rotation, can also perform an oscillating movement in the axial direction with a certain amplitude.
  • the outer screening drum 2 is fastened to a hollow shaft 11, with which it can also be set in rotation, but without an oscillating movement in the axial direction.
  • the shaft 10 of the inner sieve drum is connected to the hollow shaft 11 of the outer sieve drum by means of a screw guide 12.
  • this consists of a number of helically shaped grooves 13 on the outside of the shaft 10, in which a number of cams 14 engage on the inside of the hollow shaft 11.
  • This has the effect that inevitably with a displacement of the two screen drums 1 and 2 relative to each other in the axial direction or with a relative movement of the inner shaft 10 relative to the hollow shaft 11, the inner screen drum 1 and especially its thrust ring 1 'in addition to the feed movement, a rotary movement by a certain angle executes.
  • the grooves can also be provided on the outside of the shaft and the cams on the inside of the hollow shaft.
  • the push centrifuge described is operated as follows: through the feed pipe 5, the centrifugal material to be dewatered is introduced into the interior of the innermost sieve drum 1 immediately afterwards on the push floor 8 and flows there radially outwards onto the sieve drum 1, where the dewatering process begins.
  • the partially dewatered centrifugal material is advanced by the oscillating sieve drum 1 in the direction of the adjoining outer sieve drum 2 and is further dewatered in the process. Additional centrifugal material to be dewatered is now continuously supplied through the feed line 5.
  • the degree of rotation in the circumferential direction with a full stroke of the thrust ring must be matched to the centrifuged material to be processed and selected in accordance with the need for protection and the risk of grain breakage when loosening the partially dewatered cake.
  • NaHCO3 was at a speed of 1400 revolutions / minute and 75 strokes of the thrust ring of 60 mm amplitude per minute selected a rotation of approx. 8 ° for each stroke.
  • the degree of drainage of the NaHCO3 at the solids outlet was improved from approximately 13% to approximately 12% without increasing the speed, without disturbing grain breakage occurring. This means a reduction in the liquid content of almost 8%.
  • the additional rotary movement of the thrust ring can be carried out in the same direction as the rotation of the sieve drums, which usually results in a gentler treatment of the centrifuged material, which is particularly important for fragile, e.g. with acicular crystals is an advantage.
  • the additional rotary movement of the thrust ring can also be provided counter to the drum rotation.
  • a particularly gentle treatment of the centrifuged material is carried out here.
  • this can be on its surface be provided with a certain microroughness, as is shown schematically in FIG. 3b.
  • An even better entrainment results from a surface structure of the thrust ring 1 'which deviates from a smooth circular ring surface, for example by providing radially extending grooves 15 on the thrust ring, as shown in FIG. 3c.
  • the edge of the thrust ring 1 'can also be provided according to FIG. 3d with prongs 16 with inclined thrust surfaces, whereby the loosening of the centrifuged cake and the degree of dewatering can be increased.
  • the push floor and the second sieve drum can oscillate synchronously in the axial direction and at the same time perform a rotary movement, in the case of four-stage centrifuges, however, the first and third drums.

Abstract

In a pusher centrifuge having a plurality of rotating sieve drums (1, 2), apart from an oscillating lifting movement in the axial direction during each advance stroke, adjacent sieve drums (1, 2) carry out in addition a specific rotational movement in the circumferential direction. At the edge of the inner sieve drum (1) which acts as a pusher ring (1'), the solid cake is loosened by this rotational movement and the de-watering improved. The relative rotational movement of the two sieve drums (1, 2) can be achieved for example by means of a screw guide (12, 13, 14) of the shafts (10, 11) of the two sieve drums (1, 2). <IMAGE>

Description

Die Erfindung betrifft eine Schubzentrifuge mit mindestens zwei in einem Gehäuse rotierenden Siebtrommeln, in deren Innenraum an einem Ende Schleudergut zuführbar ist, und mit mindestens einem Schubring zwischen zwei Siebtrommeln, welcher eine in Achsenrichtung der Siebtrommeln oszillierende Bewegung zum Vorschub des teilweise entwässerten Schleudergutes auf der Innenseite der jeweils folgenden Siebtrommel in Richtung zu einem Feststoffauslass ausführt.The invention relates to a pusher centrifuge with at least two rotating sieve drums in a housing, in the interior of which centrifugal material can be fed at one end, and with at least one push ring between two sieve drums, which has an oscillating movement in the axial direction of the sieve drums for feeding the partially dewatered centrifugal material on the inside the following sieve drum in the direction of a solids outlet.

Solche Schubzentrifugen sind aus CH 624 858 und CH 627 376 bekannt und dienen zur kontinuierlichen Entwässerung eines Schleudergutes, wobei dieses über ein Zuführrohr dem inneren Ende eines Schleuderraumes zugeführt wird und auf der Innenseite der Siebtrommeln sukzessive entwässert wird. Während dieses Vorganges wird das Schleudergut durch die in Achsenrichtung oszillierende Bewegung eines oder mehrer Schubringe zwischen benachbarten Siebtrommeln allmählich in Richtung zu einem Feststoffauslass vorgeschoben, und gleichzeitig wird in der Nähe des Schubbodens nicht entwässertes Schleudergut nachgefüllt. Eine solche Schubzentrifuge weist mehrere Siebtrommeln auf, wobei jeweils zwei benachbarte Siebtrommeln relativ zueinander in Achsenrichtung oszillieren und die Kante der jeweils inneren Siebtrommel als Schubring wirkt. Beispielsweise kann bei einer zweistufigen Zentrifuge die Trommel, bei einer dreistufigen Zentrifuge der Schubboden und die zweite Trommel und bei einer vierstufigen Zentrifuge die erste und dritte Trommel in Achsenrichtung oszillieren.Such pusher centrifuges are known from CH 624 858 and CH 627 376 and are used for the continuous dewatering of centrifuged material, which is fed to the inner end of a centrifugal space via a feed pipe and is successively dewatered on the inside of the sieve drums. During this process, the centrifuged material is moved in the axial direction oscillating movement of one or more push rings between adjacent sieve drums is gradually advanced towards a solids outlet, and at the same time non-dewatered centrifugal material is refilled in the vicinity of the push floor. Such a pusher centrifuge has a plurality of sieve drums, two adjacent sieve drums each oscillating in the axial direction relative to one another and the edge of the inner sieve drum acting as a push ring. For example, in a two-stage centrifuge, the drum, in a three-stage centrifuge, the moving floor and the second drum, and in a four-stage centrifuge, the first and third drums can oscillate in the axial direction.

Mit einer solchen Schubzentrifuge ist eine kontinuierliche Entwässung eines Schleudergutes möglich, wobei dieses im Laufe des Vorschubes auf der Innenseite der Siebtrommeln vom Schleuderguteinlass bis zum Feststoffauslass allmählich im Zentrifugalfeld entwässert wird und den Feststoffauslass in weitgehend entwässertem Zustand erreicht, während das Filtrat nach aussen durch die Siebtrommeln dringt und dort abgeführt wird.Such a pusher centrifuge enables continuous dewatering of a centrifugal material, which is gradually dewatered in the centrifugal field from the centrifugal material inlet to the solids outlet during the feed on the inside of the sieve drums and reaches the solids outlet in a largely dewatered state, while the filtrate reaches the outside through the sieve drums penetrates and is discharged there.

Speziell bei hohen Schleudergut-Durchsätzen- und feinem Korn bildet sich bei solchen Schubzentrifugen auf den Siebtrommeln eine Kuchenschichtung, die sich beim Vorschub bis zum Ausstoss nicht mehr wesentlich verändert. Der gebildete Feststoffkuchen wird dabei zunehmend kompakter und damit undurchlässiger, so dass der Entwässerungsgrad und die Restfeuchte des ausgetragenen Feststoffes bei bestimmten Schleudergütern noch nicht optimal ist und eine Verlängerung der Entwässerungszeit und eine erhöhte Drehzahl und einen hohen Energieverbrauch erfordert.Especially with high centrifugal material throughput and fine grain, a cake layering is formed on such push centrifuges on the sieve drums, which does not change significantly during the feed up to the discharge. The solid cake formed becomes increasingly compact and therefore impermeable, so that the degree of drainage and the residual moisture of the discharged solid is not optimal for certain centrifugal goods and requires an extension of the dewatering time and an increased speed and a high energy consumption.

Es ist bereits vorgeschlagen worden, den während des Entwässerungsvorganges gebildeten Feststoffkuchen durch schräge Flächenelemente an den Schubringen aufzulockern und somit die Entwässerung zu beschleunigen. Bei vielen Schleudergütern führt diese Massnahme zu einer Verbesserung der Entfeuchtung ohne Erhöhung der Drehzahl der Siebtrommeln und der Aufenthaltszeit des Schleudergutes. Bei besonders empfindlichen Schleudergütern besteht jedoch bei der abrupten Scherbewegung solcher Schubzentrifugen die Gefahr von Kornbruch und Abrasion.It has already been proposed to loosen the solid cake formed during the dewatering process by means of inclined surface elements on the thrust rings and thus to accelerate the dewatering. For many centrifugal goods, this measure leads to an improvement in dehumidification without increasing the speed of the sieve drums and the residence time of the centrifuged material. In the case of particularly sensitive centrifugal goods, however, there is a risk of grain breakage and abrasion due to the abrupt shear movement of such push centrifuges.

Der Erfindung liegt die Aufgabe zugrunde, die vorstehend genannten Nachteile des Standes der Technik zu vermeiden und eine Schubzentrifuge mit erhöhtem Entwässerungsgrad und geringerer Restfeuchte des ausgetragenen Feststoffes zu schaffen, welche auch zur Entwässerung besonders empfindlichen Schleudergutes ohne Auftreten von Kornbruch und Abrasion geeignet ist.The invention has for its object to avoid the aforementioned disadvantages of the prior art and to create a push centrifuge with an increased degree of dewatering and lower residual moisture of the discharged solid, which is also suitable for dewatering particularly sensitive centrifugal material without the occurrence of grain breakage and abrasion.

Erfindungsgemäss wird diese Aufgabe dadurch gelöst, dass eine Verdreheinrichtung vorgesehen ist, mittels der der Schubring während des Vorschubes gleichzeitig eine Drehbewegung um die Achsenrichtung der Siebtrommeln ausführt.According to the invention, this object is achieved in that a rotating device is provided, by means of which the thrust ring simultaneously executes a rotary movement about the axis direction of the sieve drums during the feed.

Durch diese zusätzliche Drehbewegung des Schubringes beim Vorschubvorgang wird der Feststoffkuchen sehr schonend durch die seitliche Bewegung in Umfangs­richtung aufgelockert, so dass die Entwässerungs­leistung verbessert wird. Durch geeignete Abstimmung des Drehwinkels bei jeder Vorschubphase kann diese Auflockerung so schonend vorgenommen werden, dass ein Kornbruch weitgehend vermieden wird.Through this additional rotary movement of the thrust ring during the feed process, the solid cake is loosened very gently by the lateral movement in the circumferential direction, so that the dewatering performance is improved. By suitable adjustment of the angle of rotation at each feed phase, this loosening can be carried out so gently that grain breakage is largely avoided.

Mit besonderem Vorteil kann die Drehbewegung ebenfalls oszillierend erfolgen, so dass auch beim Rückziehen ein Rückdrehen und eine Auflockerung stattfindet, was auf einfache Weise mit einer Schraubenführung der entsprechenden Siebtrommelwellen gegeneinander bewirkt werden kann.With particular advantage, the rotary movement can also take place in an oscillating manner, so that turning back and loosening also take place when withdrawing, which can be effected in a simple manner with a screw guide of the corresponding sieve drum shafts against one another.

Es ist jedoch auch möglich, die Drehbewegung nur während der Vorschubphase vorzusehen, während das Zurückziehen des Schubringes durch eine in Achsenrichtung oder anders gerichtete Bewegung erfolgt.However, it is also possible to provide the rotary movement only during the feed phase, while the pulling ring is retracted by a movement in the axial direction or in another direction.

Die relative Drehbewegung des Schubringes kann im übrigen in Drehrichtung der Siebtrommeln gerichtet sein, was bei bruchanfälligen Kristallen von Vorteil sein kann, oder aber auch entgegengesetzt zu dieser Drehrichtung. Letzteres kann bei schwer filtrierbaren Gemischen oder niedrigen Feststoffkonzentrationen im Schleudergut von Bedeutung sein.The relative rotary movement of the thrust ring can moreover be directed in the direction of rotation of the sieve drums, which can be advantageous in the case of fragile crystals, or else opposite to this direction of rotation. The latter can be important for mixtures that are difficult to filter or low solids concentrations in the centrifuged material.

Die Erfindung wird anhand der in den Figuren dargestellten Ausführungsbeispiele näher erläutert. Es zeigen:

  • Fig. 1 eine teilweise aufgeschnittene Schubzentrifuge in perspektivischer Ansicht,
  • Fig. 2 diese Zentrifuge im Schnitt entlang einer die Rotationsachse enthaltenden Schnittebene, und
  • Fig. 3 a-d verschiedene Ausführungen der Oberfläche des Schubringes.
The invention is explained in more detail using the exemplary embodiments shown in the figures. Show it:
  • 1 is a partially cut-out pusher centrifuge in a perspective view,
  • Fig. 2 shows this centrifuge in section along a cutting plane containing the axis of rotation, and
  • Fig. 3 ad different versions of the surface of the thrust ring.

Die in den Figuren 1 und 2 in Perspektive und im Schnitt dargestellte Schubzentrifuge weist eine aus zwei rotierbaren Siebtrommeln 1 und 2 bestehende Schleudereinheit, ein diese umgebendes feststehendes Zentrifugengehäuse 3, einen an die Schleudereinheit am Auslass angrenzenden Feststoffraum 4, eine am inneren Ende der Schleudereinheit nahe einem Schubboden 8 mit einem Schleuderguteinlass 9 mündende Zuführleitung 5 für das zu entwässernde Schleudergut, einen Feststoff­auslass 6, und einen Flüssigkeitsraum 7 für die ausgeschleuderte Flüssigkeit auf.The pusher centrifuge shown in FIGS. 1 and 2 in perspective and in section has a centrifugal unit consisting of two rotatable sieve drums 1 and 2, a stationary centrifuge housing 3 surrounding it, a solid space 4 adjacent to the centrifugal unit at the outlet, and one close to the inner end of the centrifugal unit a moving floor 8 with a centrifugal material inlet 9 leading supply line 5 for the centrifuged material to be dewatered, a solids outlet 6, and a liquid space 7 for the ejected liquid.

Die innere Siebtrommel 1 ist auf einer Welle 10 angebracht, mittels der sie in Rotation mit einer bestimmten Drehzahl versetzt werden kann. Gleichzeitig ist die Welle 10 in Achsenrichtung A verschiebbar und vermag zusätzlich zu ihrer Rotation eine oszillierende Bewegung in Achsenrichtung mit einer gewissen Amplitude auszuführen. Die äussere Siebtrommel 2 ist an einer Hohlwelle 11 befestigt, mit welcher sie ebenfalls in Rotation versetzt werden kann, jedoch ohne eine oszillierende Bewegung in Achsenrichtung.The inner screening drum 1 is mounted on a shaft 10, by means of which it can be set in rotation at a certain speed. At the same time, the shaft 10 can be displaced in the axial direction A and, in addition to its rotation, can also perform an oscillating movement in the axial direction with a certain amplitude. The outer screening drum 2 is fastened to a hollow shaft 11, with which it can also be set in rotation, but without an oscillating movement in the axial direction.

Die Welle 10 der inneren Siebtrommel ist mit der Hohlwelle 11 der äusseren Siebtrommel mittels einer Schraubenführung 12 verbunden. Diese besteht im dargestellten Beispiel in einer Anzahl von schrauben­förmig ausgebildeten Nuten 13 auf der Aussenseite der Welle 10, in welche eine Anzahl Nocken 14 auf der Innenseite der Hohlwelle 11 eingreifen. Damit wird bewirkt, dass zwangsläufig bei einer Verschiebung der beiden Siebtrommeln 1 und 2 relativ zueinander in Achsenrichtung oder bei einer Relativbewegung der inneren Welle 10 gegenüber der Hohlwelle 11 die innere Siebtrommel 1 und speziell deren Schubring 1′ zusätzlich zur Vorschubbewegung eine Drehbewegung um einen bestimmten Winkel ausführt. Umgekehrt können die Nuten auch auf der Wellenaussenseite und die Nocken auf der Hohlwelleninnenseite vorgesehen sein.The shaft 10 of the inner sieve drum is connected to the hollow shaft 11 of the outer sieve drum by means of a screw guide 12. In the example shown, this consists of a number of helically shaped grooves 13 on the outside of the shaft 10, in which a number of cams 14 engage on the inside of the hollow shaft 11. This has the effect that inevitably with a displacement of the two screen drums 1 and 2 relative to each other in the axial direction or with a relative movement of the inner shaft 10 relative to the hollow shaft 11, the inner screen drum 1 and especially its thrust ring 1 'in addition to the feed movement, a rotary movement by a certain angle executes. Conversely, the grooves can also be provided on the outside of the shaft and the cams on the inside of the hollow shaft.

Die beschriebene Schubzentrifuge wird wie folgt betrieben: Durch das Zuführrohr 5 wird das zu entwässernde Schleudergut in das Innere der innersten Siebtrommel 1 unmittelbar anschliessend an den Schubboden 8 eingebracht und strömt dort radial nach aussen auf die Siebtrommel 1, wo der Entwässerungs­prozess beginnt. Durch die oszillierende Siebtrommel 1 wird das teilweise entwässerte Schleudergut in Richtung zur anschliessenden äusseren Siebtrommel 2 vorgeschoben und dabei weiter entwässert. Durch die Zuführleitung 5 wird inzwischen weiteres zu entwässerndes Schleudergut kontinuierlich nachgeliefert. Wenn das teilweise entwässerte Schleudergut das Ende der inneren Siebtrommel 1 erreicht, wird es von dessen Rand, welcher als Schubring 1′ wirkt, auf die äussere Siebtrommel 2 transportiert und dort weiter entwässert. Schliesslich wird das fertig entwässerte Schleudergut durch die relative Oszillation der beiden Siebtrommeln 1 und 2 bis zum Feststoffraum 4 transportiert, welchen es über den Feststoffauslass 6 verlässt.The push centrifuge described is operated as follows: through the feed pipe 5, the centrifugal material to be dewatered is introduced into the interior of the innermost sieve drum 1 immediately afterwards on the push floor 8 and flows there radially outwards onto the sieve drum 1, where the dewatering process begins. The partially dewatered centrifugal material is advanced by the oscillating sieve drum 1 in the direction of the adjoining outer sieve drum 2 and is further dewatered in the process. Additional centrifugal material to be dewatered is now continuously supplied through the feed line 5. When the partially dewatered centrifugal material reaches the end of the inner sieve drum 1, it is from the edge, which acts as a thrust ring 1 ', to the outer Sieve drum 2 transported and dewatered there. Finally, the completely dewatered centrifuged material is transported through the relative oscillation of the two sieve drums 1 and 2 to the solids space 4, which it leaves via the solids outlet 6.

Durch die relative Drehbewegung um die Achse A in Umfangsrichtung des Schubringes 1′ gegenüber der äusseren Siebtrommel 2 wird während des Vorschubvorganges der bereits teilweise entwässerte Kuchen schonend aufgelockert, so dass die noch gebundene Grobkapillar- und Zwickel- flüssigkeit des teilweise entwässerten Kuchens freigelegt wird, ohne einen Kornbruch zu provozieren, so dass die Entwässerung deutlich verbessert wird. Zudem hat die Bewegung entlang einer Schraubenlinie wegen der etwas grösseren Länge ohnehin einen grösseren Entwässerungseffekt. Ebenso ist der Wascheffekt bei aufgelockertem Kuchen deutlich verbessert. Hinzu kommt, dass eine Unwuchtbildung in der Zentrifuge vermieden wird, da der Kuchen mit jedem Drehhub neu geformt und damit ausgeglichen wird.Due to the relative rotational movement about the axis A in the circumferential direction of the thrust ring 1 'relative to the outer sieve drum 2, the already partially dewatered cake is loosened gently during the feed process, so that the still bound coarse capillary and gusset liquid of the partially dewatered cake is exposed without provoke a grain break so that the drainage is significantly improved. In addition, the movement along a helix has a greater drainage effect because of the somewhat longer length. The washing effect of loosened cakes is also significantly improved. In addition, the formation of an unbalance in the centrifuge is avoided, since the cake is reshaped with each rotation stroke and thus compensated.

Der Grad der Verdrehung in Umfangsrichtung bei einem vollen Hub des Schubringes ist auf das zu verarbeitende Schleudergut abzustimmen und entsprechend der Schonungsbedürftigkeit und der Gefahr von Kornbrüchen bei der Auflockerung des teilweise entwässerten Kuchens zu wählen. Bei einem Beispiel einer zweistufigen Schubzentrifuge mit 630 mm grösstem Trommeldurchmesser zur Entwässerung von beispielsweise NaHCO₃ wurde bei einer Drehzahl von 1400 Umdrehungen/Minute und 75 Hubbewegungen des Schubringes pro Minute von 60 mm Amplitude bei jedem Hub eine Verdrehung um ca. 8° gewählt. Hierbei wurde ohne Erhöhung der Drehzahl der Entwässerungsgrad des NaHCO₃ am Feststoffauslass von ca. 13% auf ca. 12% verbessert, ohne dass störender Kornbruch in Erscheinung trat. Dies bedeutet eine Verminderung des Flüssiganteiles von fast 8%.The degree of rotation in the circumferential direction with a full stroke of the thrust ring must be matched to the centrifuged material to be processed and selected in accordance with the need for protection and the risk of grain breakage when loosening the partially dewatered cake. In an example of a two-stage pusher centrifuge with 630 mm largest drum diameter for dewatering, for example, NaHCO₃ was at a speed of 1400 revolutions / minute and 75 strokes of the thrust ring of 60 mm amplitude per minute selected a rotation of approx. 8 ° for each stroke. Here, the degree of drainage of the NaHCO₃ at the solids outlet was improved from approximately 13% to approximately 12% without increasing the speed, without disturbing grain breakage occurring. This means a reduction in the liquid content of almost 8%.

Während der Erfindungsgegenstand vorstehend anhand einer Ausführung mit Schraubenführung und Verdrehung beim Vorschub und Rückdrehung beim Rückzug des Schubringes beschrieben wurde, sind auch andere Ausführungen mit analoger Wirkung möglich.While the subject matter of the invention has been described above with reference to an embodiment with a screw guide and twisting when feeding and turning back when the thrust ring is withdrawn, other embodiments with an analogous effect are also possible.

Die zusätzliche Drehbewegung des Schubringes kann in der gleichen Richtung vorgenommen werden wie die Rotation der Siebtrommeln, was in der Regel eine schonendere Behandlung des Schleudergutes bewirkt, was insbesondere bei bruchempfindlichen, z.B. bei nadelförmigen, Kristallen von Vorteil ist. Bei weniger empfindlichem Schleudergut kann jedoch die zusätzliche Drehbewegung des Schubringes auch entgegengesetzt der Trommelrotation vorgesehen sein.The additional rotary movement of the thrust ring can be carried out in the same direction as the rotation of the sieve drums, which usually results in a gentler treatment of the centrifuged material, which is particularly important for fragile, e.g. with acicular crystals is an advantage. In the case of less sensitive centrifugal material, however, the additional rotary movement of the thrust ring can also be provided counter to the drum rotation.

Der Schubring 1′ kann mit relativ glatter Oberfläche ausgeführt sein, wie in Fig. 3a gezeigt, wobei die Scherbewegung des Schleudergutes allein durch die bei der zusätzlichen Drehbewegung auftretende Gleitreibung bewirkt wird. Hierbei wird eine besonders schonende Behandlung des Schleudergutes vorgenommen. Zur besseren Mitnahme des Schleudergutes durch den Schubring in Umfangsrichtung kann dieser jedoch an seiner Oberfläche mit einer gewissen Mikrorauhigkeit versehen sein, wie in Fig. 3b schematisch dargestellt ist. Eine noch bessere Mitnahme ergibt sich durch eine von einer glatten Kreisringfläche abweichende Oberflächenstruktur des Schubringes 1′, z.B. durch Vorsehen von radial verlaufenden Rillen 15 am Schubring, wie in Fig. 3c gezeigt. Für die Behandlung bestimmter Produkte kann der Rand des Schubringes 1′ auch gemäss Fig. 3d mit Zacken 16 mit schrägen Schubflächen versehen sein, wodurch die Auflockerung des Schleudergut-Kuchens und der Entwässerungsgrad noch verstärkt werden kann.The thrust ring 1 'can be designed with a relatively smooth surface, as shown in Fig. 3a, wherein the shear movement of the centrifugal material is caused solely by the sliding friction occurring during the additional rotary movement. A particularly gentle treatment of the centrifuged material is carried out here. For better entrainment of the centrifugal material by the thrust ring in the circumferential direction, however, this can be on its surface be provided with a certain microroughness, as is shown schematically in FIG. 3b. An even better entrainment results from a surface structure of the thrust ring 1 'which deviates from a smooth circular ring surface, for example by providing radially extending grooves 15 on the thrust ring, as shown in FIG. 3c. For the treatment of certain products, the edge of the thrust ring 1 'can also be provided according to FIG. 3d with prongs 16 with inclined thrust surfaces, whereby the loosening of the centrifuged cake and the degree of dewatering can be increased.

Analoge Verhältnisse gelten bei mehr als zweistufigen Schubzentrifugen. So können bei einer dreistufigen Zentrifuge der Schubboden und die zweite Siebtrommel synchron in Achsenrichtung oszillieren und gleichzeitig eine Drehbewegung ausführen, bei vierstufigen Schubzentrifugen dagegen die erste und dritte Trommel.The same applies to more than two-stage pusher centrifuges. In the case of a three-stage centrifuge, the push floor and the second sieve drum can oscillate synchronously in the axial direction and at the same time perform a rotary movement, in the case of four-stage centrifuges, however, the first and third drums.

Claims (6)

1. Schubzentrifuge mit mindestens zwei in einem Gehäuse (3) rotierenden Siebtrommeln (1, 2) in deren Innenraum an einem Ende Schleudergut zuführbar ist, und mit mindestens einem Schubring (1′) zwischen zwei Siebtrommeln (1, 2), welcher eine in Achsenrichtung der Siebtrommeln oszillierende Bewegung zum Vorschub des teilweise entwässerten Schleudergutes auf der Innenseite der jeweils folgenden Siebtrommel (2) in Richtung zu einem Feststoffauslass (6) ausführt, dadurch gekennzeichnet, dass eine Verdreheinrichtung (12, 13, 14) vorgesehen ist, mittels der der Schubring (1′) während des Vorschubes gleichzeitig eine Drehbewegung um die Achsenrichtung (A) der Siebtrommeln (1,2) ausführt.1. thrust centrifuge with at least two in a housing (3) rotating sieve drums (1, 2) in the interior of which centrifugal material can be fed at one end, and with at least one thrust ring (1 ') between two sieve drums (1, 2), which one in Axial direction of the sieve drums executes an oscillating movement for feeding the partially dewatered centrifugal material on the inside of the following sieve drum (2) towards a solids outlet (6), characterized in that a rotating device (12, 13, 14) is provided, by means of which the Thrust ring (1 ') simultaneously performs a rotary movement about the axis direction (A) of the sieve drums (1,2) during the feed. 2. Schubzentrifuge nach Anspruch 1, dadurch gekennzeichnet, dass die Verdreheinrichtung (12, 13, 14) eingerichtet ist, während des Rückzuges des Schubringes (1′) eine Rückdrehung der Siebtrommeln (1, 2) gegeneinander auszuführen.2. Push centrifuge according to claim 1, characterized in that the rotating device (12, 13, 14) is set up to perform a return rotation of the screening drums (1, 2) against one another during the withdrawal of the push ring (1 '). 3. Schubzentrifuge nach Anspruch 2, dadurch gekennzeichnet, dass die Verdreheinrichtung eine Schraubenführung (13, 14) für die Welle (10) der den Schubring (1′) tragenden Siebtrommel (1) aufweist.3. A push centrifuge according to claim 2, characterized in that the rotating device has a screw guide (13, 14) for the shaft (10) of the push ring (1 ') carrying the sieve drum (1). 4. Schubzentrifuge nach Anspruch 3, dadurch gekennzeichnet, dass die Schraubenführung (12) zwischen der Welle (10) der einen Siebtrommel (1) und der Welle (11) der folgenden Siebtrommel (2) vorgesehen ist und schraubenförmig ausgebildete Nuten (13) der einen Welle (10) und Nocken (14) auf der anderen Welle (11) aufweist.4. A pusher centrifuge according to claim 3, characterized in that the screw guide (12) between the shaft (10) of a sieve drum (1) and the shaft (11) of the following sieve drum (2) is provided and helically shaped grooves (13) has a shaft (10) and cams (14) on the other shaft (11). 5. Schubzentrifuge nach Anspruch 4, dadurch gekennzeichnet, dass die schraubenförmig ausgebildeten Nuten (13) auf der Aussenseite der Welle (10) der den Schubring (1′) tragenden Siebtrommel (1) vorgesehen sind und die Nocken (14) auf der Innenseite der als Hohlwelle (11) ausgebildeten Welle der folgenden Siebtrommel (2).5. A push centrifuge according to claim 4, characterized in that the helical grooves (13) on the outside of the shaft (10) of the push ring (1 ') carrying the sieve drum (1) are provided and the cams (14) on the inside of the Shaft of the following screening drum (2) designed as a hollow shaft (11). 6. Schubzentrifuge nach einem der Ansprüche 1 - 5, dadurch gekennzeichnet, dass der Schubring (1′) eine von einer glatten Kreisringfläche abweichende Oberflächenstruktur (15, 16) aufweist.6. A pusher centrifuge according to one of claims 1-5, characterized in that the pusher ring (1 ') has a surface structure (15, 16) deviating from a smooth circular ring surface.
EP90118002A 1989-09-29 1990-09-19 Pusher centrifuge Expired - Lifetime EP0421188B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH3531/89A CH679016A5 (en) 1989-09-29 1989-09-29
CH3531/89 1989-09-29

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EP0421188A1 true EP0421188A1 (en) 1991-04-10
EP0421188B1 EP0421188B1 (en) 1993-11-10

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US (1) US5205933A (en)
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JP (1) JPH03118854A (en)
CN (1) CN1023383C (en)
CH (1) CH679016A5 (en)
DE (2) DE3941505C1 (en)
ES (1) ES2047225T3 (en)

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EP1468744B1 (en) * 2003-04-16 2008-06-04 Ferrum AG Pusher centrifuge with rotatable cone for pre-accelerating the mixture
KR100875704B1 (en) 2007-06-29 2008-12-23 (주)현보산업 Tub for dehydration and dehydrator using the same
PL2959977T3 (en) * 2014-06-24 2019-03-29 Ferrum Ag Double pusher centrifuge and pusher base device
CN105561658B (en) * 2014-10-14 2018-09-14 中国石油化工股份有限公司 Fusion-crystallization suspension isolates and purifies device and method
JP6618433B2 (en) * 2016-07-05 2019-12-11 月島機械株式会社 Centrifuge and centrifuge method
CN108325758A (en) * 2018-04-10 2018-07-27 巨能机械(中国)有限公司 A kind of sedimentation-filtration dewatering piston push centrifuge
CN110584446A (en) * 2018-06-12 2019-12-20 佛山市顺德区美的电热电器制造有限公司 Feeding control method, material storage device, cooking utensil and storage medium
KR102504657B1 (en) * 2019-11-18 2023-02-27 주식회사 엘지화학 Pressurizing centrifugal dehydrator
KR102504659B1 (en) * 2019-11-18 2023-02-27 주식회사 엘지화학 Pressurizing centrifugal dehydrator

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DE3810565C1 (en) * 1988-03-07 1989-07-13 Sulzer-Escher Wyss Gmbh, 7980 Ravensburg, De

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DE1044721B (en) * 1956-04-04 1958-11-20 Krauss Maffei Ag Pusher centrifuge with a stepped sieve drum
CH624858A5 (en) * 1977-11-25 1981-08-31 Escher Wyss Ag
CH627376A5 (en) * 1977-12-07 1982-01-15 Escher Wyss Ag CENTRIFUGE WITH A SOLID SPACE CONTAINING A GASEOUS MEDIUM.
JPH0635675B2 (en) * 1984-07-30 1994-05-11 大塚化学株式会社 Resin composition for electric plating

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DE1060795B (en) * 1958-03-21 1959-07-02 Krauss Maffei Ag Pusher centrifuge, especially for long-fiber centrifugal materials
DE3810565C1 (en) * 1988-03-07 1989-07-13 Sulzer-Escher Wyss Gmbh, 7980 Ravensburg, De

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Publication number Publication date
ES2047225T3 (en) 1994-02-16
US5205933A (en) 1993-04-27
DE59003454D1 (en) 1993-12-16
JPH03118854A (en) 1991-05-21
CH679016A5 (en) 1991-12-13
CN1023383C (en) 1994-01-05
EP0421188B1 (en) 1993-11-10
CN1050688A (en) 1991-04-17
DE3941505C1 (en) 1990-12-13

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