EP0342455B1 - Filter centrifuge for the separation of suspensions - Google Patents
Filter centrifuge for the separation of suspensions Download PDFInfo
- Publication number
- EP0342455B1 EP0342455B1 EP89108187A EP89108187A EP0342455B1 EP 0342455 B1 EP0342455 B1 EP 0342455B1 EP 89108187 A EP89108187 A EP 89108187A EP 89108187 A EP89108187 A EP 89108187A EP 0342455 B1 EP0342455 B1 EP 0342455B1
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- European Patent Office
- Prior art keywords
- gas
- collecting space
- syphon
- liquid
- pressure
- 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
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- 239000000725 suspension Substances 0.000 title abstract description 5
- 238000000926 separation method Methods 0.000 title abstract 2
- 239000007789 gas Substances 0.000 claims abstract 11
- 239000007788 liquid Substances 0.000 claims description 35
- 239000000706 filtrate Substances 0.000 claims description 17
- 230000001419 dependent effect Effects 0.000 claims description 5
- 238000001914 filtration Methods 0.000 abstract description 11
- 238000011001 backwashing Methods 0.000 abstract description 4
- 239000007787 solid Substances 0.000 abstract description 3
- 239000012065 filter cake Substances 0.000 description 10
- 238000006073 displacement reaction Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 230000002706 hydrostatic effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04B—CENTRIFUGES
- B04B3/00—Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04B—CENTRIFUGES
- B04B15/00—Other accessories for centrifuges
- B04B15/08—Other accessories for centrifuges for ventilating or producing a vacuum in the centrifuge
Definitions
- the invention relates to a "filter centrifuge for separating suspensions" according to the preamble of claim 1.
- Rotating siphon devices are attached to the drums of filter centrifuges according to German Patent Specification 22 60 461, which flow through the filtrate separated from the suspension after it has passed the filter medium and a collecting space, with the exclusion of gas.
- the filtrate gets into a ring cup attached to the outside of the drum and is made from it e.g. derived by means of a peeling pipe which can be swung in and out.
- the peeling tube is also used to adjust the liquid level in the ring cup. If this level is lowered into a region radially outside the filter medium, the siphon device causes a pressure drop under the filter medium, relative to the pressure in the centrifuge housing.
- This increases the driving force that causes the filtration compared to conventional centrifuges by the pressure difference that exists between the surface of the filter cake and the collecting space, and the filtration is accelerated.
- gas which has penetrated into the collecting space can be displaced after each centrifuging batch, ie after the filter cake has been peeled out of the drum.
- liquid is poured into the ring cup of the siphon device and the peeling tube is pivoted out of the ring cup.
- a suction line branches off from the collecting space and communicates with the centrifuge housing via a liquid suction pump, a vacuum space being established in the collecting space radially within the liquid level, which regulates the filtration speed elevated.
- this device requires gas in the form of a vacuum gas space, the vacuum being able to be ensured only if sufficient quantities of filtrate liquid act on the liquid suction pump.
- a filter centrifuge is known from EP-A 0 247 401, which likewise shows a gas discharge line branching off from a gas space inside the filtrate collecting space, via which, when the filter centrifuge is operated with compressed gas filtration, compressed gas which has penetrated the filter cake is passed from the gas space to the outside of the centrifuge housing can.
- compressed gas filtration requires a gas space to allow compressed gas to flow through the filter cake.
- a device which allows gas which has penetrated into the collecting space during a centrifuging batch to be rapidly displaced into the housing surrounding the drum.
- gas discharge lines are preferably provided in the rear wall of the drum and are provided with a pressure-dependent outflow device.
- the outflow device can consist of a valve which opens at a slight overpressure in the collecting chamber compared to the pressure prevailing in the centrifuge housing and closes at an opposite pressure drop, that is to say a greater pressure in the housing than in the collecting chamber.
- the outflow device consists of a rotating siphon which is filled with liquid and is designed such that gas flows from the collecting space to the housing at a low pressure drop from the collecting space to the housing and gas closure at a greater pressure drop from the housing to the collecting space is guaranteed.
- the feed and discharge devices filling pipe (2), peeling knife (3), solids chute (4), pressure relief valve (5), backwash pipe (6) and filtrate peeling pipe (7) are attached to the housing (1).
- the siphon drum (9) with the filter medium (10), the collecting space (11), the siphon disc (12) and the ring cup (13) is seated on the shaft (8). According to the figure, a filter cake (14) is deposited on the filter medium (10).
- the collecting space (11) is partially filled with filtrate liquid (15), which has a lower (radially larger) liquid level in the ring cup (13).
- filtrate liquid (15) which has a lower (radially larger) liquid level in the ring cup (13).
- the centrifuge drum (9) is then charged with suspension via the filling tube (2).
- the filtrate peeling tube (7) swings into the ring cup (13) and lowers the liquid level in the ring cup (13) compared to the level in the collecting chamber (11).
- a low pressure arises under the filter medium (10) compared to the surrounding housing.
- the pressure difference is determined by the accelerated mass of the liquid column ⁇ h +.
- a ⁇ h + For example, with an acceleration of 1000 x 9.81 m / s2 and water as the filtrate liquid, a ⁇ h + of 20 mm, a pressure difference of 2 bar.
- an increasing gas cushion is formed in the collecting space (11) as a result of gas ingress through the filter cake or degassing of the filtrate, ⁇ h + and thus the additional pressure drop become smaller.
- the filtrate peeling tube (7) is now swung out again and liquid is poured into the ring cup (13) through the backwashing tube (6).
- This process results in a short-term reduction in the filtration speed because it e.g. can be accomplished in 20 s.
- the peeling tube (7) is then swiveled in again, whereby the check valve (18) closes automatically and ⁇ h + again assumes a maximum value.
- a siphon device is used instead of the check valve (18).
- the horizontal branch (19) of the bore (17) is connected to a down pipe (20), the lower end of which (21) in the siphon cup (21).
- liquid is filled into the siphon cup (21) through the refill tube (22).
- the refill tube (22) can also take over the function of the backwash tube (6) because the liquid overflowing from the small siphon cup (21) gets into the ring cup (13).
- Fig. 2 shows the device in the "filtering" operating state. Because in this case the internal pressure of the centrifuge housing is greater than the pressure in the collecting chamber (11), the two liquid columns ⁇ h + generate the same, hydrostatic pressures. Because the liquid column ⁇ h + in the downpipe (20) is subject to a lower centrifugal acceleration than the column between the collecting space (11) and the ring cup (13), which is located radially further outwards, this inner column has a larger, radial extension. Both columns close the gas to the collecting space (11).
- Fig. 3 shows the device in the "displacement" operating state.
- gas has entered the collecting space (11) from the filtrate liquid and / or through the filter cake, this must be displaced.
- liquid is simultaneously filled into the siphon cup (21) and the ring cup (13) with the refill tube (22).
- the liquid column displaces ⁇ h - the gas which has entered the collecting space (11) through the downpipe (20). Because ⁇ h - in the siphon cup (21) can only assume a low value due to the low rim ring, the gas bubbles through this siphon cup into the interior of the housing.
- the rim of the siphon cup (21) can be kept very low because its cross-sectional area has a multiple of the cross-sectional area of the downpipe (20).
- a slight lowering of the level in the siphon cup (21) is sufficient to build up a liquid column ⁇ h + in the downpipe (20) corresponding to the pressure difference without it being necessary to add liquid through the refill pipe (22) .
- Fig. 4 shows a pressure sensor (23) in the filtrate collecting space (11) which reports pressure measurement values to the control system via cable (24) and slip rings (not shown in the drawing) or a transmitter.
- the displacement of gas from the collecting space (11) into the centrifuge housing (1) can be controlled in a pressure-dependent manner.
- the filtrate peeling tube (7) swings out and liquid is filled into the ring cup (13) through the backwashing tube (6).
- the advantage of the device according to the invention is not limited to the displacement of gas during centrifugation.
- the device can also be used advantageously if the solid has been peeled apart from a residual layer.
- liquid had to be filled into the ring cup (13) when the peeling tube (7) was swung out, on the one hand to displace gas before the next batch and on the other hand to regenerate the remaining layer and the filter medium (10) by backwashing. If the resistance of the residual layer and filter medium was high, this process was time-consuming on the one hand and difficult to control on the other hand. In the case of large resistances, and possibly different for each batch, the volume flow of the liquid supplied would have to be adapted to this resistance. If the volume flow was too large, some of the liquid ran unused into the centrifuge housing via the rim ring of the ring cup (13).
- the collecting space (11) was still largely filled with gas, a considerable pressure could arise against the filter medium (10) due to the length of the liquid column ⁇ h, until the filter medium was damaged.
- the pressure in the collecting space (11) can only be as great as the resistance of the gas outflow device. Only when the liquid reaches the filter medium (10) from the collecting space (11) does the pressure difference still work remaining small column ⁇ h - and the filter medium (10) is flowed through.
- the liquid supplied to the ring cup (13) can be metered precisely due to the new device and an ineffective overflow via the rim ring of the ring cup (13) is avoided.
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- Centrifugal Separators (AREA)
- Filtering Of Dispersed Particles In Gases (AREA)
Abstract
Description
Die Erfindung bezieht sich auf eine "Filterzentrifuge zum Trennen von Suspensionen" nach dem Oberbegriff des Anspruchs 1.The invention relates to a "filter centrifuge for separating suspensions" according to the preamble of
An den Trommeln von Filterzentrifugen nach der Deutschen Patentschrift 22 60 461 sind mitrotierende Siphoneinrichtungen angebracht, welche das von der Suspension abgetrennte Filtrat, nachdem es das Filtermittel und einen Sammelraum passiert hat, unter Gasabschluß durchströmt.Rotating siphon devices are attached to the drums of filter centrifuges according to German Patent Specification 22 60 461, which flow through the filtrate separated from the suspension after it has passed the filter medium and a collecting space, with the exclusion of gas.
Das Filtrat gelangt in eine an der Außenseite der Trommel angebrachte Ringtasse und wird aus dieser z.B. mittels eines ein- und ausschwenkbaren Schälrohres abgeleitet. Das Schälrohr dient gleichzeitig zur Einstellung des Flüssigkeitsniveaus in der Ringtasse. Wird dieses Niveau in einen Bereich radial außerhalb des Filtermittels abgesenkt, so bewirkt die Siphoneinrichtung einen Druckabfall unter dem Filtermittel, relativ zum Druck im Zentrifugengehäuse.The filtrate gets into a ring cup attached to the outside of the drum and is made from it e.g. derived by means of a peeling pipe which can be swung in and out. The peeling tube is also used to adjust the liquid level in the ring cup. If this level is lowered into a region radially outside the filter medium, the siphon device causes a pressure drop under the filter medium, relative to the pressure in the centrifuge housing.
Dadurch wird die treibende Kraft, welche die Filtration bewirkt, gegenüber konventionellen Zentrifugen um die Druckdifferenz, die zwischen der Oberfläche des Filterkuchens und dem Sammelraum herrscht, erhöht und die Filtration beschleunigt.This increases the driving force that causes the filtration compared to conventional centrifuges by the pressure difference that exists between the surface of the filter cake and the collecting space, and the filtration is accelerated.
Diese Druckdifferenz bildet sich jedoch zurück, wenn die Filtratflüssigkeit gasförmige Bestandteile in den Sammelraum unter dem Filtermittel abgibt oder wenn Gas durch das Filtermittel gelangt.However, this pressure difference regresses when the filtrate liquid releases gaseous components into the collecting space under the filter medium or when gas passes through the filter medium.
Mit der Vorrichtung nach DPS 22 60 461 kann nach jeder Zentrifugiercharge, d.h. nachdem der Filterkuchen aus der Trommel ausgeschält worden ist, in den Sammelraum eingedrungenes Gas verdrängt werden. Dazu wird Flüssigkeit in die Ringtasse der Siphoneinrichtung gefüllt und das Schälrohr aus der Ringtasse geschwenkt.With the device according to
Infolgedessen bildet sich ein von außen gegen das Filtermittel gerichtete Druckgefälle und das eingedrungene Gas wird durch das Filtermittel getrieben.As a result, a pressure drop is formed from the outside against the filter medium and the gas which has penetrated is forced through the filter medium.
Diese Verdrängung von Gas ist jedoch nur möglich, nachdem der Filterkuchen bis auf eine Restschicht entfernt wurde. Wenn sich der Filterkuchen noch in der Trommel befindet, ist der Widerstand zur Entfernung von Gas durch den Filterkuchen zu groß und außerdem würde bei diesem Verfahrensschritt die Filtration gestört.However, this displacement of gas is only possible after the filter cake has been removed except for a residual layer. If the filter cake is still in the drum, the resistance to gas removal through the filter cake is too great and the filtration would also be disturbed in this process step.
Aus der FR-A- 2 234 042 ist es ferner auch bekannt, daß vom Sammelraum eine Saugleitung abzweigt, die über eine Flüssigkeits-Saugpumpe mit dem Zentrifugengehäuse in Verbindung steht, wobei sich im Sammelraum radial innerhalb des Flüssigkeitsspiegels ein Unterdruckraum einstellt, der die Filtrationsgeschwindigkeit erhöht. Diese Einrichtung setzt im Gegensatz zu einer Siphonzentrifuge Gas in Form eines Unterdruck-Gasraumes voraus, wobei der Unterdruck nur sichergestellt werden kann, wenn genügende Mengen an Filtratflüssigkeit die Flüssigkeits-Saugpumpe beaufschlagen.From FR-A-2 234 042 it is also known that a suction line branches off from the collecting space and communicates with the centrifuge housing via a liquid suction pump, a vacuum space being established in the collecting space radially within the liquid level, which regulates the filtration speed elevated. In contrast to a siphon centrifuge, this device requires gas in the form of a vacuum gas space, the vacuum being able to be ensured only if sufficient quantities of filtrate liquid act on the liquid suction pump.
Aus der EP-A 0 247 401 ist eine Filterzentrifuge bekannt, die ebenfalls eine von einem Gasraum innerhalb des Filtratsammelraumes abzweigende Gasabführleitung zeigt, über die beim Betrieb der Filterzentrifuge mit Druckgasfiltration Druckgas, das den Filterkuchen durchdrungen hat, vom Gasraum nach außerhalb des Zentrifugengehäuses geleitet werden kann. Im Gegensatz zum Betrieb einer Siphonzentrifuge ist bei der Druckgasfiltration ein Gasraum zum einwandfreien Durchströmen des Filterkuchens mit Druckgas erforderlich.A filter centrifuge is known from EP-A 0 247 401, which likewise shows a gas discharge line branching off from a gas space inside the filtrate collecting space, via which, when the filter centrifuge is operated with compressed gas filtration, compressed gas which has penetrated the filter cake is passed from the gas space to the outside of the centrifuge housing can. In contrast to the operation of a siphon centrifuge, compressed gas filtration requires a gas space to allow compressed gas to flow through the filter cake.
Mit der Erfindung wird eine Vorrichtung geschaffen die es gestattet, während einer Zentrifugiercharge in den Sammelraum eingedrungenes Gas rasch in das die Trommel umschließenden Gehäuse zu verdrängen.With the invention, a device is created which allows gas which has penetrated into the collecting space during a centrifuging batch to be rapidly displaced into the housing surrounding the drum.
Erfindungsgemäß wird dies dadurch erreicht, daß vorzugsweise in der Trommelrückwand Gasabführleitungen angebracht und mit einer druckabhängigen Ausströmvorrichtung versehen sind.According to the invention this is achieved in that gas discharge lines are preferably provided in the rear wall of the drum and are provided with a pressure-dependent outflow device.
Die Ausströmvorrichtung kann aus einem Ventil bestehen, welches bei einem geringen Überdruck im Sammelraum gegenüber dem im Zentrifugengehäuse herrschenden Druck öffnet und bei einem umgekehrten Druckgefälle, also größerem Druck im Gehäuse als im Sammelraum, schließt. Eine andere erfindungsgemäße Lösung besteht darin, daß die Ausströmvorrichtung aus einem rotierenden Siphon besteht der mit Flüssigkeit gefüllt wird und so beschaffen ist, daß bei einem geringen Druckgefälle vom Sammelraum zum Gehäuse Gas vom Sammelraum zum Gehäuse strömt und bei einem größeren Druckgefälle vom Gehäuse zum Sammelraum Gasabschluß gewährleistet ist.The outflow device can consist of a valve which opens at a slight overpressure in the collecting chamber compared to the pressure prevailing in the centrifuge housing and closes at an opposite pressure drop, that is to say a greater pressure in the housing than in the collecting chamber. Another solution according to the invention is that the outflow device consists of a rotating siphon which is filled with liquid and is designed such that gas flows from the collecting space to the housing at a low pressure drop from the collecting space to the housing and gas closure at a greater pressure drop from the housing to the collecting space is guaranteed.
In den Zeichnungen sind Ausführungsbeispiele dargestellt.
Es zeigen:
- Abb. 1:
- Einen Schnitt durch eine Zentrifuge mit Rotationssiphon und einem Rückschlagventil zur Gasableitung aus dem Sammelraum.
- Abb. 2:
- Eine Zentrifugentrommel, bei der anstelle eines Rückschlagventils eine Siphoneinrichtung zur wechselseitigen Gasabsperrung und -ableitung dient, im Betriebszustand der Gasabsperrung.
- Abb. 3:
- Wie Abb. 2, jedoch im Betriebszustand der Gasableitung.
- Abb. 4:
- Zeigt einen Teilschnitt durch eine Zentrifugentrommel mit Rotationssiphon und einem Drucksensor im Filtrat-Sammelraum.
Show it:
- Fig. 1:
- A section through a centrifuge with a rotary siphon and a non-return valve for gas discharge from the collecting space.
- Fig. 2:
- A centrifuge drum, in which a siphon device is used instead of a non-return valve for mutual gas shut-off and discharge, in the operating state of the gas shut-off.
- Fig. 3:
- Like Fig. 2, but in the operating state of the gas discharge.
- Fig. 4:
- Shows a partial section through a centrifuge drum with a rotary siphon and a pressure sensor in the filtrate collecting chamber.
Nach Abb. 1 sind am Gehäuse (1) die Zu- und Ableiteinrichtungen Füllrohr (2), Schälmesser (3), Feststoffrutsche (4), Überdruckventil (5), Rückspülrohr (6) sowie Filtrat-Schälrohr (7) befestigt.According to Fig. 1, the feed and discharge devices filling pipe (2), peeling knife (3), solids chute (4), pressure relief valve (5), backwash pipe (6) and filtrate peeling pipe (7) are attached to the housing (1).
Auf der Welle (8) sitzt die Siphontrommel (9) mit dem Filtermittel (10), dem Sammelraum (11), der Siphonscheibe (12) und der Ringtasse (13). Nach der Abb. ist auf dem Filtermittel (10) ein Filterkuchen (14) abgelagert. Der Sammelraum (11) ist teilweise mit Filtratflüssigkeit (15) gefüllt, die in der Ringtasse (13) ein niedrigeres (radial größeres) Flüssigkeitsniveau hat. In der Trommelrückwand (16) befindet sich wenigstens eine Bohrung (17) und wenigstens ein Rückschlagventil (18).The siphon drum (9) with the filter medium (10), the collecting space (11), the siphon disc (12) and the ring cup (13) is seated on the shaft (8). According to the figure, a filter cake (14) is deposited on the filter medium (10). The collecting space (11) is partially filled with filtrate liquid (15), which has a lower (radially larger) liquid level in the ring cup (13). There is at least one bore (17) and at least one check valve (18) in the rear wall of the drum (16).
Nach den Abb. 2 und 3 schließt sich an den horizontalen Ast (19) der Bohrung (17) ein radial nach außen gerichtetes Rohr (20) an, welches in der Siphontasse (21) abgetaucht ist, wenn Flüssigkeit durch das Nachfüllrohr (22) zugeführt wurde.According to Figs. 2 and 3, the horizontal branch (19) of the bore (17) is followed by a radially outwardly directed pipe (20) which is immersed in the siphon cup (21) when liquid flows through the refill pipe (22). was fed.
Die Arbeitsweise der Vorrichtung gem. Abb. 1 ist folgende:
Vor jeder Zentrifugiercharge werden durch das Rückspülrohr (6) bei ausgeschwenktem Filtrat-Schälrohr (7) sowohl die Ringtasse (13) als auch der Sammelraum (11) nahezu vollständig mit Flüssigkeit gefüllt.The operation of the device acc. Fig. 1 is as follows:
Before each batch of centrifugation, both the ring cup (13) and the collecting space (11) are almost completely filled with liquid through the backwash tube (6) with the filtrate peeling tube (7) swung out.
Anschließend wird die Zentrifugentrommel (9) über das Füllrohr (2) mit Suspension beschickt. Dabei schwenkt das Filtrat-Schälrohr (7) in die Ringtasse (13) ein und senkt den Flüssigkeitsspiegel in der Ringtasse (13) gegenüber dem Spiegel im Sammelraum (11) ab. Infolgedessen entsteht unter dem Filtermittel (10) ein gegenüber dem umgebenden Gehäuse geringer Druck. Die Druckdifferenz wird durch die beschleunigte Masse der Flüssigkeitssäule Δ h + bestimmt. So erzeugt z.B. bei einer Beschleunigung von 1000 x 9,81 m/s² und Wasser als Filtratflüssigkeit ein Δ h + von 20 mm eine Druckdifferenz von 2 bar. Wenn jedoch infolge von Gaseinbrüchen durch den Filterkuchen oder von Entgasung des Filtrats ein zunehmendes Gaspolster im Sammelraum (11) gebildet wird, werden Δ h + und damit das zusätzliche Druckgefälle kleiner.The centrifuge drum (9) is then charged with suspension via the filling tube (2). The filtrate peeling tube (7) swings into the ring cup (13) and lowers the liquid level in the ring cup (13) compared to the level in the collecting chamber (11). As a result, a low pressure arises under the filter medium (10) compared to the surrounding housing. The pressure difference is determined by the accelerated mass of the liquid column Δ h +. For example, with an acceleration of 1000 x 9.81 m / s² and water as the filtrate liquid, a Δ h + of 20 mm, a pressure difference of 2 bar. However, if an increasing gas cushion is formed in the collecting space (11) as a result of gas ingress through the filter cake or degassing of the filtrate, Δ h + and thus the additional pressure drop become smaller.
Zur Wiederherstellung der die Filtration beschleunigenden Druckdifferenz wird jetzt das Filtrat-Schälrohr (7) erneut ausgeschwenkt und durch das Rückspülrohr (6) Flüssigkeit in die Ringtasse (13) gefüllt. Dadurch wird ein umgekehrtes Druckgefälle vom Sammelraum (11) zum Gehäuse-Innenraum von der Flüssigkeitssäule Δ h - erzeugt und infolgedessen das Gas aus dem Sammelraum (11) durch die Bohrung (17) und das Rückschlagventil (18) verdrängt. Dieser Vorgang bewirkt eine nur kurzzeitige Minderung der Filtrationsgeschwindigkeit, weil er z.B. in 20 s bewerkstelligt werden kann. Anschließend wird das Schälrohr (7) wieder eingeschwenkt, wodurch das Rückschlagventil (18) selbstätig schließt und Δ h + wieder einen Maximalwert annimmt.To restore the pressure difference accelerating the filtration, the filtrate peeling tube (7) is now swung out again and liquid is poured into the ring cup (13) through the backwashing tube (6). This creates a reverse pressure drop from the collecting chamber (11) to the interior of the housing from the liquid column Δ h - and consequently displaces the gas from the collecting chamber (11) through the bore (17) and the check valve (18). This process results in a short-term reduction in the filtration speed because it e.g. can be accomplished in 20 s. The peeling tube (7) is then swiveled in again, whereby the check valve (18) closes automatically and Δ h + again assumes a maximum value.
Nach den Abb. 2 und 3 wird anstelle des Rückschlagventils (18) eine Siphoneinrichtung verwendet. Dazu wird der horizontale Ast (19) der Bohrung (17) an ein Fallrohr (20) angeschlossen, dessen unteres Ende (21) in die Siphontasse (21) taucht. Zur Erzielung der gewünschten Ventilwirkung wird durch das Nachfüllrohr (22) Flüssigkeit in die Siphontasse (21) gefüllt. Das Nachfüllrohr (22) kann gleichzeitig die Funktion des Rückspülrohres (6) mit übernehmen, weil die aus der kleinen Siphontasse (21) überlaufende Flüssigkeit in die Ringtasse (13) gelangt.According to Figs. 2 and 3, a siphon device is used instead of the check valve (18). For this purpose, the horizontal branch (19) of the bore (17) is connected to a down pipe (20), the lower end of which (21) in the siphon cup (21). To achieve the desired valve action, liquid is filled into the siphon cup (21) through the refill tube (22). The refill tube (22) can also take over the function of the backwash tube (6) because the liquid overflowing from the small siphon cup (21) gets into the ring cup (13).
Abb. 2 zeigt die Vorrichtung im Betriebszustand "Filtrieren". Weil in diesem Falle der Innendruck des Zentrifugengehäuses großer ist, als der Druck im Sammelraum (11), erzeugen die beiden Flüssigkeitssäulen Δ h + gleiche, hydrostatische Drücke. Weil die Flüssigkeitssäule Δ h + im Fallrohr (20) einer geringeren Zentrifugalbeschleunigung unterliegt, als die Säule zwischen dem Sammelraum (11) und der Ringtasse (13), die radial weiter außen liegt hat diese innere Säule eine größere, radiale Erstreckung. Beide Säulen bewirken Gasabschluß zum Sammelraum (11).Fig. 2 shows the device in the "filtering" operating state. Because in this case the internal pressure of the centrifuge housing is greater than the pressure in the collecting chamber (11), the two liquid columns Δ h + generate the same, hydrostatic pressures. Because the liquid column Δ h + in the downpipe (20) is subject to a lower centrifugal acceleration than the column between the collecting space (11) and the ring cup (13), which is located radially further outwards, this inner column has a larger, radial extension. Both columns close the gas to the collecting space (11).
Abb. 3 zeigt die Vorrichtung im Betriebszustand "Verdrängen". Nachdem in den Sammelraum (11) aus der Filtratflüssigkeit und/oder durch den Filterkuchen Gas eingedrungen ist, muß dieses verdrängt werden. Dazu wird nach dem Beispiel mit dem Nachfüllrohr (22) gleichzeitig Flüssigkeit in die Siphontasse (21) und die Ringtasse (13) gefüllt. Infolgedessen verdrängt die Flüssigkeitssäule Δ h - das in den Sammelraum (11) eingedrungene Gas durch das Fallrohr (20). Weil Δ h - in der Siphontasse (21) wegen des niedrigen Bordringes nur einen geringen Wert annehmen kann, blubbert das Gas durch diese Siphontasse in den Gehäuse-Innenraum. Der Bordring der Siphontasse (21) kann sehr niedrig gehalten werden, weil deren Querschnittsfläche ein Vielfaches der Querschnittsfläche des Fallrohres (20) aufweist. Somit genügt beim Betriebszustand nach Abb. 2 eine geringe Niveau-Senkung in der Siphontasse (21), um eine der Druckdifferenz entsprechende Flüssigkeitssäule Δ h + im Fallrohr (20) aufzubauen, ohne daß es erforderlich ist, Flüssigkeit durch das Nachfüllrohr (22) zuzugeben.Fig. 3 shows the device in the "displacement" operating state. After gas has entered the collecting space (11) from the filtrate liquid and / or through the filter cake, this must be displaced. For this purpose, according to the example, liquid is simultaneously filled into the siphon cup (21) and the ring cup (13) with the refill tube (22). As a result, the liquid column displaces Δ h - the gas which has entered the collecting space (11) through the downpipe (20). Because Δ h - in the siphon cup (21) can only assume a low value due to the low rim ring, the gas bubbles through this siphon cup into the interior of the housing. The rim of the siphon cup (21) can be kept very low because its cross-sectional area has a multiple of the cross-sectional area of the downpipe (20). Thus, in the operating state according to Fig. 2, a slight lowering of the level in the siphon cup (21) is sufficient to build up a liquid column Δ h + in the downpipe (20) corresponding to the pressure difference without it being necessary to add liquid through the refill pipe (22) .
Abb. 4 zeigt einen Drucksensor (23) im Filtrat-Sammelraum (11), der über Kabel (24) und in der Zeichnung nicht dargestellte Schleifringe oder einen Sender Druck-Meßwerte an die Steuerung meldet. Dadurch kann die Verdrängung von Gas aus dem Sammelraum (11) in das Zentrifugengehäuse (1) druckabhängig gesteuert werden. Sobald ein wählbarer Solldruck im Sammelraum bzw. unter dem Filtermittel (10) überschritten wird schwenkt das Filtrat-Schälrohr (7) aus und durch das Rückspülrohr (6) wird Flüssigkeit in die Ringtasse (13) gefüllt.Fig. 4 shows a pressure sensor (23) in the filtrate collecting space (11) which reports pressure measurement values to the control system via cable (24) and slip rings (not shown in the drawing) or a transmitter. As a result, the displacement of gas from the collecting space (11) into the centrifuge housing (1) can be controlled in a pressure-dependent manner. As soon as a selectable target pressure in the collecting space or under the filter medium (10) is exceeded, the filtrate peeling tube (7) swings out and liquid is filled into the ring cup (13) through the backwashing tube (6).
Der Vorteil der erfindungsgemäßen Vorrichtung beschränkt sich nicht auf die Verdrängung von Gas während der Zentrifugation.The advantage of the device according to the invention is not limited to the displacement of gas during centrifugation.
Die Vorrichtung kann auch vorteilhaft angewendet werden, wenn der Feststoff bis auf eine Restschicht ausgeschält worden ist. In diesem Falle mußte schon bisher Flüssigkeit in die Ringtasse (13) bei ausgeschwenktem Schälrohr (7) gefüllt werden, um einerseits vor der folgenden Charge Gas zu verdrängen und andererseits, um die Restschicht und das Filtermittel (10) durch Rückspülung zu regenerieren. Wenn der Widerstand von Restschicht und Filtermittel groß war, war dieser Vorgang einerseits zeitaufwendig und andererseits schwer steuerbar. Bei großen, und möglicherweise bei jeder Charge unterschiedlichen Widerständen hätte der Volumenstrom der zugeführten Flüssigkeit diesem Widerstand angepaßt werden müssen. War der Volumenstrom zu groß, so lief ein Teil der Flüssigkeit über den Bordring der Ringtasse (13) ungenutzt in das Zentrifugengehäuse. Dabei konnte, wenn der Sammelraum (11) noch weitgehend mit Gas gefüllt war, ein aufgrund der Länge der Flüssigkeitssäule Δ h - erheblicher Druck gegen das Filtermittel (10) entstehen, bis zur Beschädigung des Filtermittels. Mit der erfindungsgemäßen Vorrichtung kann der Druck im Sammelraum (11) nur so groß sein, wie der Widerstand der Gas-Abströmvorrichtung. Erst wenn die Flüssigkeit das Filtermittel (10) vom Sammelraum (11) aus erreicht, wirkt die Druckdifferenz der noch verbleibenden, kleinen Säule Δ h - und das Filtermittel (10) wird durchströmt.The device can also be used advantageously if the solid has been peeled apart from a residual layer. In this case, liquid had to be filled into the ring cup (13) when the peeling tube (7) was swung out, on the one hand to displace gas before the next batch and on the other hand to regenerate the remaining layer and the filter medium (10) by backwashing. If the resistance of the residual layer and filter medium was high, this process was time-consuming on the one hand and difficult to control on the other hand. In the case of large resistances, and possibly different for each batch, the volume flow of the liquid supplied would have to be adapted to this resistance. If the volume flow was too large, some of the liquid ran unused into the centrifuge housing via the rim ring of the ring cup (13). If the collecting space (11) was still largely filled with gas, a considerable pressure could arise against the filter medium (10) due to the length of the liquid column Δ h, until the filter medium was damaged. With the device according to the invention, the pressure in the collecting space (11) can only be as great as the resistance of the gas outflow device. Only when the liquid reaches the filter medium (10) from the collecting space (11) does the pressure difference still work remaining small column Δ h - and the filter medium (10) is flowed through.
Die der Ringtasse (13) zugeführte Flüssigkeit läßt sich aufgrund der neuen Vorrichtung genau dosieren und ein wirkungsloser Überlauf über den Bordring der Ringtasse (13) wird vermieden.The liquid supplied to the ring cup (13) can be metered precisely due to the new device and an ineffective overflow via the rim ring of the ring cup (13) is avoided.
Claims (5)
- A centrifuge with a centrifugal drum comprising a coaxial filter means and with, disposed radially outside the filter means, a filtrate collecting space which has at least one outlet orifice, the collecting space having connected to it a co-rotating syphon means which temporarily prevents gas entering the collecting space, at least one gas discharge pipe being disposed and connecting the collecting space (11) to the centrifuge housing (1), characterised in that the gas discharge pipe (17) extends through a pressure-dependent non-return valve (18; 20, 21) so that gas is able to emerge from the collecting space.
- An apparatus according to Claim 1, characterised in that the device for pressure-dependent gas discharge is a syphon (20, 21) co-rotating with the centrifuge drum (9) and adapted to be filled with liquid.
- An apparatus according to Claim 1, characterised in that means are provided for feeding liquid through an annular cup (13) with which gases which have entered the annular space (11) can be expelled through the device for pressure-dependent gas discharge.
- An apparatus according to Claims 2 and 3, characterised by a pipe (22) for topping up the syphon cup (21).
- An apparatus according to Claim 1, characterised by a pressure sensor (23) in the collecting space (15).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT89108187T ATE94426T1 (en) | 1988-05-19 | 1989-05-05 | FILTER CENTRIFUGE FOR SEPARATING SUSPENSIONS. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3817126A DE3817126A1 (en) | 1988-05-19 | 1988-05-19 | FILTER CENTRIFUGE TO SEPARATE SUSPENSIONS |
| DE3817126 | 1988-05-19 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0342455A2 EP0342455A2 (en) | 1989-11-23 |
| EP0342455A3 EP0342455A3 (en) | 1990-11-07 |
| EP0342455B1 true EP0342455B1 (en) | 1993-09-15 |
Family
ID=6354734
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP89108187A Expired - Lifetime EP0342455B1 (en) | 1988-05-19 | 1989-05-05 | Filter centrifuge for the separation of suspensions |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5032258A (en) |
| EP (1) | EP0342455B1 (en) |
| JP (1) | JPH0217957A (en) |
| AT (1) | ATE94426T1 (en) |
| DE (1) | DE3817126A1 (en) |
| ES (1) | ES2045245T3 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0714109B2 (en) * | 1988-06-23 | 1995-02-15 | 三菱マテリアル株式会社 | Ceramic composite circuit board |
| DE19703353C2 (en) * | 1997-01-30 | 2003-10-09 | Krauss Maffei Process Technolo | Process for operating a filter centrifuge |
| FR2808458B1 (en) * | 2000-05-02 | 2002-08-09 | Cogema | CONTINUOUSLY ROTARY FILTERING DEVICE OF A LIQUID SUCH AS A SOLUTION CONTAINING A PRECIPITY |
| US20070278146A1 (en) * | 2006-05-31 | 2007-12-06 | Cook Melvin W | Centrifugal Fluid Filtration Devices, Systems and Methods |
| CN104984836A (en) * | 2015-06-16 | 2015-10-21 | 镇江港和新型建材有限公司 | Centrifugal machine with double-layer rotary drum structure |
| US20200316501A1 (en) * | 2017-12-19 | 2020-10-08 | Xeros Limited | Filter for a treatment apparatus |
| 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 |
| CN112317143A (en) * | 2020-09-27 | 2021-02-05 | 濮阳天健生物科技有限公司 | Filtering centrifugal separator for synthesizing 5-methyltetrazole |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1190842A (en) * | 1915-11-13 | 1916-07-11 | Frank K Atkins | Centrifugal-pressure filter. |
| US3377019A (en) * | 1965-09-15 | 1968-04-09 | Baker Perkins Inc | Methods and apparatus for maintaining a liquid head in a centrifuge |
| DE1757532C3 (en) * | 1968-05-17 | 1979-08-23 | Rudolf F. Ing.(Grad.) 2000 Norderstedt Garbaty | Outlet regulator for a centrifugal separator |
| FR206069A (en) * | 1970-06-09 | |||
| DE2260461C3 (en) * | 1972-12-11 | 1980-06-04 | Krauss-Maffei Ag, 8000 Muenchen | Filter centrifuge |
| DE2603610A1 (en) * | 1976-01-30 | 1977-08-04 | Krauss Maffei Ag | CENTRIFUGAL DRUM WITH SIDE FILTRATION |
| US4095615A (en) * | 1976-05-21 | 1978-06-20 | Ramco Manufacturing, Inc. | Check valve and siphon tube assembly employing same |
| FR2424530A2 (en) * | 1978-04-25 | 1979-11-23 | Faure Jean | Filling cups for centrifuging of samples - is performed by creating vacuum and then establishing atmospheric pressure again |
| NL7804735A (en) * | 1978-05-03 | 1979-11-06 | Esmil B V Stationsstraat 48 | VACUUM FILTER WITH ROTATING DRUM. |
| SU787951A1 (en) * | 1978-12-21 | 1980-12-15 | Ленинградский Ордена Ленина, Ордена Октябрьской Революции И Ордена Трудового Красного Знамени Горный Институт Им. Г.В.Плеханова | Method of determining filtering layer resistance in vacuum filters |
| FR2496498A1 (en) * | 1980-12-19 | 1982-06-25 | Robatel Slpi | Filtration centrifuge - where perforated filter wall carries radial manometer tubes creating hydrostatic depression which assists filtration |
| DE3617768A1 (en) * | 1986-05-27 | 1987-12-03 | Krauss Maffei Ag | FILTER CENTRIFUGE |
| DE3626314C2 (en) * | 1986-08-02 | 1993-11-11 | Krauss Maffei Ag | Device for separating suspensions |
| US4759857A (en) * | 1986-08-04 | 1988-07-26 | Acuna Eduardo M | Open siphon filter method |
| DE3726227A1 (en) * | 1987-08-07 | 1989-02-16 | Krauss Maffei Ag | DEVICE FOR RESULTS CONTROLLING A FILTER CENTRIFUGE |
-
1988
- 1988-05-19 DE DE3817126A patent/DE3817126A1/en active Granted
-
1989
- 1989-05-05 US US07/348,282 patent/US5032258A/en not_active Expired - Fee Related
- 1989-05-05 EP EP89108187A patent/EP0342455B1/en not_active Expired - Lifetime
- 1989-05-05 ES ES89108187T patent/ES2045245T3/en not_active Expired - Lifetime
- 1989-05-05 AT AT89108187T patent/ATE94426T1/en not_active IP Right Cessation
- 1989-05-16 JP JP1120584A patent/JPH0217957A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ES2045245T3 (en) | 1994-01-16 |
| EP0342455A3 (en) | 1990-11-07 |
| JPH0217957A (en) | 1990-01-22 |
| ATE94426T1 (en) | 1993-10-15 |
| DE3817126C2 (en) | 1991-04-04 |
| US5032258A (en) | 1991-07-16 |
| EP0342455A2 (en) | 1989-11-23 |
| DE3817126A1 (en) | 1989-11-30 |
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