WO2010020285A1 - Procédé de lavage d'un gâteau de matière solide, et centrifugeuse - Google Patents

Procédé de lavage d'un gâteau de matière solide, et centrifugeuse Download PDF

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Publication number
WO2010020285A1
WO2010020285A1 PCT/EP2008/060977 EP2008060977W WO2010020285A1 WO 2010020285 A1 WO2010020285 A1 WO 2010020285A1 EP 2008060977 W EP2008060977 W EP 2008060977W WO 2010020285 A1 WO2010020285 A1 WO 2010020285A1
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WO
WIPO (PCT)
Prior art keywords
centrifuge
washing
liquid
drum
cake
Prior art date
Application number
PCT/EP2008/060977
Other languages
German (de)
English (en)
Inventor
Werner Stahl
Gernot Busch
Philipp Ruhstaller
Original Assignee
Ferrum Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ferrum Ag filed Critical Ferrum Ag
Priority to PCT/EP2008/060977 priority Critical patent/WO2010020285A1/fr
Publication of WO2010020285A1 publication Critical patent/WO2010020285A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B15/00—Other accessories for centrifuges
    • B04B15/12—Other accessories for centrifuges for drying or washing the separated solid particles
    • 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
    • B04B3/00—Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering
    • B04B3/02—Centrifuges 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

Definitions

  • the invention relates to a method and a centrifuge according to the preamble of independent claims 1 and 9.
  • centrifuges in various embodiments are widely used and are used in a variety of fields.
  • discontinuously operating centrifuges such as peeler centrifuges, are preferably used, while, in particular, when continuously large quantities of a solid-liquid mixture are to be separated, continuously operating
  • Pusher centrifuges are used advantageously.
  • one-stage or multi-stage pusher centrifuges as well as so-called double-skid centrifuges, are used, but so-called screw centrifuges and a number of other concepts have long been well known to the skilled person.
  • the centrifuges can be aligned vertically or horizontally with respect to the gravitational field of the earth and can be very specific depending on the application.
  • a very comprehensive overview of centrifuge technology is available e.g. W. Stahl in his work “Industrial Centrifuges", DrM Press, 2004.
  • the known from the prior art pusher centrifuges are usually continuous filter centrifuges.
  • single-stage and multi-stage pusher centrifuges are known, wherein the multi-stage pusher centrifuge from an outer screen drum and at least one arranged in the outer screen drum screening stage, which is also designed as a screen drum consists.
  • several screening stages can be arranged concentrically in one another, so that two, three and multi-stage pusher centrifuges can be realized, all screening stages being driven very quickly synchronously about a common axis of rotation.
  • a solid-liquid mixture to be separated passes in the operating state continuously through a fixed inlet pipe in a arranged in the innermost screening stage, also synchronously co-rotating, mixture distributor and is distributed evenly on the innermost screening stage over the entire screen circumference. Most of the liquid is already centrifuged off here and it forms a solid cake. In contrast, a single-stage pusher centrifuge does not include any further screening stages except the outer screening drum. Here, in order to convey the solids cake in the sieve drum, the moving soil oscillates, which simultaneously co-rotates synchronously with the outer sieve drum.
  • the innermost stage also referred to as the first stage, performs a rotation movement about the axis of rotation in addition to the rotation Oscillation movement in the direction of the axis of rotation.
  • This oscillatory movement is generated hydraulically via a thrust piston with reversing mechanism.
  • the solids cake is pushed in ring sections, corresponding to the stroke length of the oscillation, from the first to the second stage and finally leaves the pusher centrifuge via an outlet opening.
  • the solid cake in the sieve drum is washed continuously with the addition of washing liquid on the solid cake.
  • An unsolved problem in the prior art relates to the washing of the solid cake, especially when using pusher centrifuges.
  • pusher centrifuges With pusher centrifuges, one knows that the cake is never completely saturated; this is in contrast to peeler centrifuges.
  • the washing of the solids cake can be done in such a way that with a supernatant of washing liquid, e.g. Washing water is worked on the solids cake. This means that a "lake" of washing liquid can form, with the result that the pores of the solid cake are always completely filled with washing liquid
  • the pusher centrifuge can not work with a supernatant on the solids cake, if only for that reason. because, due to the design and process, the supernatant of washing liquid would simply flow out of the centrifuge drum, which was open at one end, so that it would not be possible to reach a volume filled with washing liquid.
  • the object of the invention is therefore to propose an improved method for washing a solid cake, which allows the use of a pusher centrifuge to produce a filled with washing liquid heap, while reducing the necessary amount of washing liquid both pusher centrifuges and discontinuous centrifugal centrifuges can, while optimizing the washing result.
  • Another object of the invention is to provide a corresponding centrifuge with which the method of the invention is feasible.
  • the invention thus relates to a method for washing a solids cake in a centrifugal field of a centrifuge, which centrifuge comprises a centrifuge drum rotatable about a rotation axis.
  • a mixture of at least one solid and a liquid phase comprising a mother liquid is introduced into the centrifuge drum, the mixture is at least partially separated into the liquid phase and the solids cake under the action of the centrifugal field, and the solid cake is washed with a washing liquid for washing.
  • the solid cake is pulsed with the washing liquid for a predetermined pulse duration.
  • the washing results in peeler centrifuges can be significantly improved and especially massive washing liquid can be saved.
  • the inventive method thus better cake washing, less solubility losses and a lower consumption of washing liquid is achieved.
  • washing liquid runs like a film along the particle surface is not so true, at least for wholly or partly dewatered aggregates. Rather, it is the case with unsaturated particles that the washing liquid runs off the particle as trickle or "watering.” This is why conventional purging in pusher centrifuges does not fill all the pores and the washing is not optimal.
  • the new discovery is that a cake is not possible should be pre-drained before the wash begins, or that the wash should saturate the cake again.
  • the pulse duration is selected so that a radial zone of the solid cake is saturated in a predetermined radial width by the washing liquid with a predetermined degree of saturation.
  • a pulsed washing device is provided in the centrifuge drum for impinging the solids cake with the washing liquid, the washing device preferably a washing nozzle, in a special round jet nozzle or slot nozzle, or a wash tube, in particular a wash tube with a plurality of wash tube nozzles and / or wash tube openings and / or with a wash pipe slot.
  • At least a first washing device and a second washing device may be provided in the centrifuge drum, and / or the first washing device is in the axial direction with respect to the second washing device offset and / or the first washing device is offset with respect to the second washing device in a circumferential direction of the centrifuge drum.
  • the washing liquid is applied in the region of a washing zone on the solid cake, which washing zone extends over a predetermined axial extent in an axial direction of the centrifuge drum.
  • the washing liquid may be e.g. be fed with a piston pump.
  • the flow rate can be adjusted via the stroke length. This has the advantage that no major pressure pulsations occur in the inlet.
  • Rotary valve means in this context that a wash tube, which is provided for example for dispensing the washing liquid with a slot inside a rotating body containing a constant speed via a rotary drive.
  • a suitably formed slot opens due to the geometric conditions, the slot, for example, during about 20% of the time, for example, on the geometry of the rotating part and other time intervals are adjustable.
  • a corresponding rotary drive is provided with stuffing box.
  • a pneumatic valve is installed directly in front of the centrifuge, which is clocked accordingly.
  • a known pulsation damper is advantageously used.
  • a preferred solution for the implementation of pulsating washing is a washing tube with flanged drive, a longitudinal slot of eg 50mmx1 mm gap size and an internal rotatable valve body. This is possible in a very simple manner, the pulsed supply of the washing liquid.
  • Such a solution can be prepared as a unit, for example, and is ready to use on any machine. There must only be an appropriate opening on the centrifuge or, if not present, provided where the washer can be attached by, for example, clamping or screwing. Thus, even existing centrifuge can be very easily converted so that they can be carried out with the inventive method.
  • the solid cake is acted upon by the washing device at least once with washing liquid and / or the pulse duration is selected equal to a rotation time of the centrifuge drum.
  • an exit velocity of the washing liquid from the washing device is particularly advantageously chosen to be approximately equal to a peripheral speed of the centrifuge drum in such a way that splashing of the washing liquid on the surface of the solids cake is prevented.
  • the centrifuge is in particular a batch centrifuge, in particular a peeler centrifuge, or in a very important practical embodiment, the centrifuge is a continuously operating centrifuge, in particular a screw centrifuge, particularly preferably an oscillating pusher centrifuge with a Oszillationshub, advantageously a on or multi-stage pusher centrifuge, or a double-pusher centrifuge, wherein the axial extent of the washing zone is preferably greater than the oscillation stroke of the pusher centrifuge.
  • the invention further relates to a centrifuge for washing a solids cake in a centrifugal field of the centrifuge, which centrifuge rotatable about a rotation axis
  • Centrifuge drum comprises.
  • a mixture of at least one solid and a liquid phase comprising a mother liquid can be introduced, wherein in the operating state, the mixture under an effect of the centrifugal field in the liquid phase and the solid cake is at least partially separable, wherein the solid cake for washing with a washing liquid can be acted upon.
  • a pulsable or pulsating washing device is provided in the centrifuge drum, so that the solid cake can be pulsed with the washing liquid with a predetermined pulse duration.
  • the washing device of the centrifuge according to the invention is preferably a washing nozzle, in particular a round jet nozzle or slot nozzle, or a wash tube, in particular a wash tube with a plurality of wash tube nozzles and / or wash tube openings and / or with a wash tube slot.
  • a valve body rotatable by a drive is provided for the pulsating discharge of the washing liquid via the wash tube nozzles and / or via the wash tube openings and / or via the wash tube slot in the wash tube.
  • At least a first washing device and a second washing device may be provided in the centrifuge drum, and / or the first
  • Washing device is offset with respect to the second washing device in the axial direction and / or the first washing device is offset with respect to the second washing device in a circumferential direction of the centrifuge drum.
  • the washing device is preferably arranged and configured in the centrifuge drum such that the washing liquid can be applied to the solids cake in the region of a washing zone, the washing zone being provided over a predetermined axial extent along an axial direction of the centrifuge drum.
  • An exit velocity of the washing liquid from the washing device is preferably selected to be approximately equal to a peripheral speed of the centrifuge drum such that splashing of the washing liquid on the surface of the solid cake can be prevented. Namely, when the exit velocity of the washing liquid is approximately equal to the peripheral speed of the solid cake to be acted upon, the washing liquid is pre-accelerated in the rotating frame and the washing liquid settles in the form of a liquid curtain substantially tangential and without spraying on the surface or splash on the solid cake ,
  • the centrifuge according to the invention is in particular a discontinuously operating centrifuge, in particular a centrifugal centrifuge, the centrifuge according to the invention is a continuously operating centrifuge, in particular a screw centrifuge, preferably an oscillating pusher centrifuge with an oscillation stroke, more preferably a single or multistage pusher centrifuge, or a double pusher centrifuge, wherein the axial extent of the washing zone is preferably greater than the oscillation stroke of the pusher centrifuge.
  • the pulsating washing is defined in a specific embodiment substantially by the following parameters: the continuous washing amount W konti [kg / h], the max. current washing quantity W pulse [kg / h], the pulse duration PD: [sec], the number of pulses PA [1 / sec], the axial length D of the liquid jet [mm], the width B of the jet [mm], and the length L of the washing tube or the position of the washing nozzle [mm].
  • the pulsating wash is not coupled to the lifting movement of the drum, it can basically be done independently of the number of strokes. However, it should be ensured that the entire cake surface after
  • the maximum instantaneous amount of washing water Wmax for the pulsating feed is to be chosen so that there is no flooding, imbalance or flushing out of the cake.
  • cooking salt NaCl
  • the required amount of wash water is, for example, 100 kg / t of solid, which means that a total of 100 kg of washing water per ton of solid is needed.
  • the bulk density in the centrifuge is 1400 kg / m3 and the pore volume 35%, so that 65% solids are present.
  • the pulse duration should take a total of 0.2 sec.
  • W cont 100 l / h
  • T ref 1 s
  • W pulse 500 l / h (see above)
  • PA 1 sec -1
  • PD 0.2 sec 2 sec-1 is increased
  • PD decreases to 0.1 sec.
  • the pulse duration and the number of pulses each have their own restrictions, ie they can not be changed arbitrarily, for example, the pulse duration must have a certain minimum time, so that the cake is completely wetted in the circumferential direction.
  • These restrictions take precedence and may result in other uses of washing fluid result, according to the above formula, k would change as a function of the washing liquid consumption.
  • a restriction on the pulse duration PD is that it must be at least as long as a 360 degree rotation of the centrifuge drum lasts.
  • the maximum speeds of all P120-PM230 series tested vary between 900 - 3600 min-1. If the minimum speeds make up 1/3 of the maximum, you get speeds between 300 - 1200 min-1. For a complete drum revolution, it takes between 0.05 - 0.2 sec. Across all series. The pulse duration must therefore be set according to the size and is not a fixed size.
  • the pulse duration PD depends significantly on the size of the centrifuge used.
  • the pulse duration PD can advantageously be in the range of 0.05 s to approx. 0.2 s.
  • a restriction for the number of pulses PA is that they should preferably be at least as large as the number of strokes per minute. If this is not satisfied, a strip of unwashed cake may result in the axial cake direction. To be sure that this does not happen, there should be an overlap of the wetted axial cake strips, i. the number of pulses per minute should be greater than the number of strokes per minute. Also possible are multiples of it, but then the pulse duration at constant k can be correspondingly reduced.
  • the stroke rates are in practice, for example, between about 30-100 strokes / min, for all series.
  • the preferred number of pulses depends, inter alia, on the size of the centrifuge used, and PA may for example be in the range of 30 min-1 to -100 min-1, which corresponds to a range of 0.5 sec-1 to 1 .7 sec-1.
  • the washing nozzle or washing nozzles are preferably placed at the end of the first stage in a multi-stage pusher centrifuge.
  • There are two phases during an entire stroke cycle. Assuming a two-stage pusher centrifuge, the cake is first moved forward in the forward stroke on the screen, so there is a relative speed between the cake and the washing nozzle. The cake is pushed by the maximum mechanical stroke, for example, H 50 mm, which, however, may vary depending on the series, multiplied by the conveying efficiency, for example about 0.70-0.80, so in the specific example discussed here by about 38 mm axially forward.
  • the return stroke pushes the sieve of the 1.
  • Step back under the cake ie there is no relative speed between cake and nozzle.
  • it is possible to activate the pulsation only when the return stroke takes place then it would be guaranteed that the same amount of washing liquid will always hit each cm 2 of cake surface (no relative speed between nozzle and cake surface in the return stroke).
  • In the forward stroke results due to the relative speed nozzle / cake surface a variable wetting depth in the radial direction. Whether in the concrete case better washing results are achieved with or without synchronization, depends on very different factors and is to be determined in a specific case, for example in test series.
  • the pulsation nozzle is activated by determining PD and PA. Depending on the series, number of strokes, etc, the activation will then take place once on the return stroke, once on the forward stroke, but is not set consciously, as long as not synchronized.
  • the axial length D of the liquid jet is determined inter alia by the fact that in extreme cases (as discussed above) the number of pulses per minute corresponds to the number of strokes per minute.
  • the length of the liquid jet on the cake surface is measured. Since per stroke the cake surface moves axially forward by the effective stroke, the length of the liquid jet should be at least equal to the effective stroke.
  • the cake wetting in the forward stroke is not uniform over the axial length (cake particles that just run out of the washing jet during activation of the nozzle are hardly wetted, particles which are just running into the washing jet will be wetted to a maximum) should There is an extra overlap length to minimize these different wetting depths.
  • One way is to choose the length of the liquid jet about 10-30% larger than the mechanical stroke, so for example around 55-65 mm long.
  • the axial length of the liquid jet may also change in the case of a conventional nozzle.
  • the nozzle is designed as a slot, this difficulty can be avoided.
  • an axial length D of the jet W was selected to be in a range of 55mm to 65mm, or more generally, the length D of the jet W was selected to be between one mechanical stroke and one-third of the mechanical stroke.
  • the width B of the nozzle jet is determined by the fact that the water jets should impinge on the cake surface with the same speed as possible. With classical installation (jet jet vertically downwards on cake surface) should therefore the fanning of the beam, which the width B determined, preferably not more than 10 ° to 30 °, otherwise the peripheral rays, which have a greater path to the cake surface, already hit braked.
  • the width B ultimately depends on the distance nozzle to the cake surface. As an example, the nozzle is installed 100 mm above the cake surface, the fan angle is 25 °, so the width B of the jet is 42 mm. Depending on the type of nozzle there is no fanning (slot nozzles), but only a liquid curtain with parallel liquid jets.
  • the positioning of the washing nozzle should preferably be in the case of a multistage pusher centrifuge on FIG. Stage, but not in the inlet, because there the cake is too unstable, but rather towards the end of the first stage, preferably in the area of the rear third.
  • the length L of the washing tube can thus be very different, in the range of, for example, approximately 400 mm (PM230) up to approximately 1100 mm (P120).
  • the number of nozzles can also be varied, depending on the amount of washing liquid, it may be advantageous to mount a plurality of nozzles, e.g. offset in the axial direction or at the same axial height but to be positioned at different locations on the circumference. These different number of nozzles and different positions can also influence the washing result, since the cake is washed several times in succession, for example.
  • nozzles can be determined differently depending on the application. In question come ordinary round jet nozzles, slot nozzles with parallel jets and other nozzle types, which are known in the art in principle.
  • FIG. 1 in section an inventive pusher centrifuge with pusierender
  • FIG. 2 shows a section along the section line I-I according to FIG. 1;
  • FIGS. 3a-3c shows the two-stage pusher centrifuge of FIGS. 3a-3c partly in a plan view
  • FIG. 5a washing device with offset in the axial direction of the washing nozzles Fig. 5b washing device with circumferentially offset washing nozzles;
  • FIG. 6b shows a section of the rotary valve along the section line M-II according to FIG. 6a.
  • FIG. 1 shows, in a schematic illustration, essential components of a first simple exemplary embodiment of a pusher centrifuge with washing device according to the invention.
  • FIG. 1 a single-stage pusher centrifuge is shown schematically in Fig. 1 by way of example for reasons of clarity. It is understood that the representation of FIG. 1 is to be understood as an example and the description of course also for two- and higher-stage pusher centrifuges, as shown by way of example in the further illustrations by hand two-stage pusher centrifuges, or even for double pusher centrifuges in an analogous manner and is transferable accordingly.
  • the pusher centrifuge according to the invention which is referred to in its entirety by the reference numeral 1, serves to separate a mixture 4 into a solid 41 and into a liquid phase 42 and comprises as essential components one by one
  • Rotary axis 101 rotatable about a drum axis outer centrifuge drum 3, which is housed in a housing G.
  • the drum axis is operatively connected to a drum drive 100 in a manner known per se, so that the centrifuge drum 3 can be set into rapid rotation about the rotation axis 101 by the drum drive 100.
  • a drum drive 100 in multi-stage pusher centrifuges 1, as will be shown by way of example in the following figures, at least one further screening stage is arranged.
  • a mixture distributor 102 is provided with a push floor device 103, wherein the push floor device 103 is arranged back and forth along the rotation axis 101, so that the solids cake 2 is displaceable by means of the push floor device 103.
  • the centrifuge drum 3 and, as in the case of multistage pusher centrifuges 1, the further screening stage have screen openings 11, through which liquid phase 42 from the solids cake 2 or from the mixture 4, through the centrifugal forces, passes in a known manner with rapid rotation can be discharged to the outside.
  • the mixture distributor 102 is preferred
  • Push bottom device 103 is arranged, which allows continuously supplied through the feed device E mixture 4 on the inner peripheral surface 31 of the centrifuge drum 3 and in multi-stage pusher centrifuges on the Siebgen Chemistry the Sieve level by introducing into a void R, which has arisen when moving the solid cake 2 to distribute.
  • the pusher bottom device 103 is designed as an annular region that with the annular region in single-stage pusher centrifuges 1 of the deposited in the centrifuge drum 3, and multistage pusher centrifuges 1 of the deposited in the screening stage solid cake 2 by an oscillation along the axis of rotation 101 of the pusher bottom device 103rd and / or the screening stage, in single-stage pusher centrifuges 1 from the centrifuge drum 3, or in multi-stage pusher centrifuges 1 in the screening drum or in any other existing screening stage, is displaceable.
  • a washing device 7 is provided, which is arranged in the centrifuge drum 3 and configured so that the solid cake 2 a predetermined pulse duration over an axial extent L w , preferably larger is as the oscillation L H of the moving floor device 103, pulsating with washing liquid 5 can be applied.
  • FIG. 2 shows a section along the section line I-I according to FIG. 1, on which the influence of the pulsating washing on the radial distribution of the washing liquid 5 in the solids cake 2 can be seen particularly well.
  • the washing nozzle 7, 71, 72 is explained in a multi-stage pusher centrifuge 1, as illustrated in FIGS. 3a to 3c using the example of a two-stage pusher centrifuge 1, preferably at the end of the first stage. There are two phases during an entire stroke cycle. If, according to FIGS. 3 a to 3c, one starts from a two-stage pusher centrifuge 1, the solids cake 2, 21 is first displaced forward in the preliminary stroke according to FIG. 3 b on the screen, ie there is an axial relative velocity between the solids cake 2, 21 and the washing nozzle 7, 71, 72.
  • the return stroke according to FIG. 3c the sieve of FIG. 1 slides.
  • a synchronization of the stroke with the pulsation of the washing liquid is possible, but not essential.
  • the axial width B of the liquid jet is determined inter alia by the fact that in extreme cases (as discussed above) the number of pulses per minute corresponds to the number of strokes per minute.
  • the width B of the liquid jet on the cake surface is measured. Since per stroke the cake surface moves axially forward by the effective stroke, the width B of the liquid jet should be at least equal to the effective stroke.
  • the cake wetting in the forward stroke (relative speed to the nozzle) is not uniform over the axial length (cake particles that just run out of the washing jet during activation of the nozzle are hardly wetted, particles which are just running into the washing jet will be wetted to a maximum) should There is an extra overlap length to minimize these different wetting depths.
  • One possibility is to choose the length of the liquid jet about 10-30% larger than the mechanical stroke, so here for example about 55-65 mm long. At different Cake heights can also change the axial length of the liquid jet in the case of a conventional nozzle. However, in the case that the nozzle is designed as a slot, these difficulties can be more easily avoided.
  • an axial width B of the nozzle jet W was selected in a range of 55mm to 65mm, or more generally, the width B of the jet stream W was selected in the range between a mechanical stroke to 1 .3 times the mechanical stroke.
  • the width B of the nozzle jet is determined by the fact that the water jets should impinge on the cake surface with the same speed as possible. In classical installation (nozzle jet vertically downwards on cake surface), therefore, the fanning out of the beam which determines the width B should preferably be no more than 10 ° to 30 °, otherwise the peripheral rays which have a greater distance up to the cake surface, already slowed down.
  • the width B ultimately depends on the distance nozzle 7, 71, 72 to the cake surface. As an example, the nozzle 7, 71, 72 in Figs. 3a to 3c is installed 100 mm above the cake surface, the fan angle is 25 °, thus the width B of the jet is 42 mm.
  • the positioning of the washing nozzle 7, 71, 72 should preferably be in the first stage in a multi-stage pusher centrifuge 1, but not in the inlet, because there the solid cake 2 is too unstable, but rather towards the end of the first stage, preferably in the region of the rear third , Depending on the size, the length of the wash tube can thus be very different, for example, in the range of approximately 400 mm to approximately 1100 mm.
  • FIGS. 3 a to 3c show the geometric relationships discussed in FIGS. 3 a to 3c for a two-stage pusher centrifuge once again somewhat simplified and partly in a plan view of the centrifuge drum 1.
  • the washing water jet W is fanned out by an angle ⁇ , so that the solids cake 2, 21, 22 can act on the predetermined axial extent L w with washing liquid 5.
  • washing nozzles 7, 71, 72 may, of course, be located at any suitable position in the centrifuge drum 3 and not only at the positions in the centrifuge drum 3, as shown schematically herein for the specific embodiments.
  • a plurality of washing devices 7, 71, 72 may also be provided in the centrifuge drum 3, for example in order to apply more washing liquid 5 per unit of time to the solids cake or, for example, to ensure a more even and / or more gentle application.
  • Washing device 7 comprises a plurality of axially offset against each other scrubbing nozzles 7, 71, 72, or that according to FIG. 5b, the washing device 7 has a plurality of circumferentially U offset washing nozzles 7, 71, 72.
  • FIG. 6b shows a section of the rotary valve 7, 71, 72 along the section line M-II according to FIG. 6a.
  • a rotary valve 7, 71, 72 which has a particularly high importance in practice, the amount of washing liquid 5 is set externally via a valve and a quantity measurement, wherein the pulsation pressure is reduced in front of the valve via a pulsation damper.
  • the valve, the quantity measurement and the pulsation damper, all devices which are known in principle to the person skilled in the art, are not explicitly shown in FIGS. 6a and 6b.
  • a rotary valve 7, 71, 72 is to be understood as meaning a washing tube 7, 71, 72 which is suitable for dispensing the washing liquid 5, e.g.
  • washing tube 7, 71, 72 in the interior comprises a valve body 8 in the form of a rotary body 8, which via a rotary drive M, e.g. via a separate electric motor M or via a coupling M with the drive of the centrifuge 1 is constantly running.
  • a correspondingly formed slot 701 opens due to the geometric conditions, for example, during about 20% of the time, wherein, for example, on the geometry of the rotary member 8 other time intervals are adjustable.
  • a corresponding rotary drive M is provided with stuffing box.

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Abstract

L'invention porte sur un procédé de lavage d'un gâteau de matière solide (2, 21, 22) dans un champ centrifuge d'une centrifugeuse (1), laquelle centrifugeuse (1) comprend un tambour de centrifugation (3) pouvant tourner autour d'un axe de rotation (101). Dans le tambour de centrifugation (3), on introduit un mélange (4) d'au moins une matière solide (41) et d'une phase liquide (42) comprenant un liquide mère, on sépare au moins partiellement le mélange (4) sous l'effet du champ centrifuge appliqué à la phase liquide (42) et au gâteau de matière solide (2, 21, 22), et, pour laver le gâteau de matière solide (2, 21, 22), on lui applique un liquide de lavage (5). Selon l'invention, le gâteau de matière solide (2, 21, 22) est soumis d'une manière pulsée au liquide de lavage (5) pendant une durée d'impulsion prédéfinie. En outre, l'invention porte sur une centrifugeuse comportant un dispositif de lavage (7, 71, 72) pour la mise en oevre du procédé.
PCT/EP2008/060977 2008-08-21 2008-08-21 Procédé de lavage d'un gâteau de matière solide, et centrifugeuse WO2010020285A1 (fr)

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PCT/EP2008/060977 WO2010020285A1 (fr) 2008-08-21 2008-08-21 Procédé de lavage d'un gâteau de matière solide, et centrifugeuse

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5300233A (en) * 1993-02-09 1994-04-05 Dorr-Oliver Incorporated Process of displacement washing in a centrifuge filter
EP0785030A2 (fr) * 1996-01-17 1997-07-23 Matsumoto Machine Mfg. Co., Ltd. Procédé de filtration centrifuge et appareil pour sa mise en oeuvre
DE10311997A1 (de) * 2003-03-19 2004-10-07 Johannes Gerteis Stülpfilterzentrifuge

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5300233A (en) * 1993-02-09 1994-04-05 Dorr-Oliver Incorporated Process of displacement washing in a centrifuge filter
EP0785030A2 (fr) * 1996-01-17 1997-07-23 Matsumoto Machine Mfg. Co., Ltd. Procédé de filtration centrifuge et appareil pour sa mise en oeuvre
DE10311997A1 (de) * 2003-03-19 2004-10-07 Johannes Gerteis Stülpfilterzentrifuge

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