EP0490270B1 - Verfahren und Einrichtung zur Regelung einer Vollmantelzentrifuge - Google Patents

Verfahren und Einrichtung zur Regelung einer Vollmantelzentrifuge Download PDF

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Publication number
EP0490270B1
EP0490270B1 EP19910120887 EP91120887A EP0490270B1 EP 0490270 B1 EP0490270 B1 EP 0490270B1 EP 19910120887 EP19910120887 EP 19910120887 EP 91120887 A EP91120887 A EP 91120887A EP 0490270 B1 EP0490270 B1 EP 0490270B1
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EP
European Patent Office
Prior art keywords
control
scroll
axial
axial forces
screw
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
Application number
EP19910120887
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German (de)
English (en)
French (fr)
Other versions
EP0490270A3 (de
EP0490270A2 (de
Inventor
Hans Andreas Weil
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Individual
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Individual
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Publication of EP0490270A2 publication Critical patent/EP0490270A2/de
Publication of EP0490270A3 publication Critical patent/EP0490270A3/de
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Anticipated expiration legal-status Critical
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B1/00—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles
    • B04B1/20—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles discharging solid particles from the bowl by a conveying screw coaxial with the bowl axis and rotating relatively to the bowl
    • B04B1/2016—Driving control or mechanisms; Arrangement of transmission gearing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B13/00—Control arrangements specially designed for centrifuges; Programme control of centrifuges

Definitions

  • the present invention relates to a method for controlling a solid bowl centrifuge, such as a decanter, in which control signals are obtained from changing forces on the screw and are used to adjust the machine control.
  • Solid bowl centrifuges of the type in question work, for example, as decanters in separation processes for clarification, dewatering, wet classification, solid-liquid extraction and the like.
  • a screw rotates in the same direction in an outer drum with a small gap, which acts as a conveying element for the deposited relatively dry residue due to a low speed difference, whereas the clarified Liquid flows out of the inner jacket of the outer drum in the opposite direction.
  • the differential or screw speed or the weir disc height or the feed quantity can be regulated.
  • the screw torque is still the most important guide variable for such a regulation.
  • One reason for this is the relative simplicity of getting this information, depending on the drive system, as an electrical or hydrostatic variable.
  • the torque is a statement of the degree to which the machine is filled with solids and their quantity in the drying section.
  • the torque is a statement made up of the degree of filling on the one hand and the degree of compaction of the solid on the other and its shear strength.
  • the torque of the screw is used as the reference variable for the screw speed.
  • the arrangement for obtaining the torque as a measurable variable can usually also be used as an actuator of the control
  • the screw speed control is a control that the flexibility of the centrifuge over a wide field of work ensures the simultaneous optimization of the separation results.
  • One of the torque depending on the screw speed control, the compression time is decisive, for the torque-dependent feed control it is the sedimentation and compression time.
  • this mass is able to "swallow” any disturbance from the inlet, that is to say that everywhere in this mass the concentration, compression and shear strength increase monotonically in the centrifugal direction.
  • the flow properties of the sediments decrease, which is the rule with increasing compaction, this mass begins to develop a "memory" for disturbance variables on the inlet side, and the tendency of the control loop to oscillate increases.
  • a reduction in the control factor or amplifier factor of the control loop or the damping of the command variable restricts the working area of the control so much that the latter is no longer able to cope with a currently large amount of solids, and it therefore misses one of its most important purposes.
  • the object of the present invention is therefore to provide a method for controlling a solid bowl centrifuge of the aforementioned type, which allows the aforementioned problems of the prior art to be overcome and an optimal one under all possible operating conditions To accomplish regulation.
  • this is first achieved in that axial forces or components thereof occurring at least on the worm are measured and converted into feedback signals for the adjustment.
  • a preferred embodiment of the method can then be seen in that the axial forces are measured locally or in sections and / or at several locations on the screw, in which case the measured axial forces are at least partially static.
  • the measured axial forces can also be the sum of the static and dynamic axial forces.
  • the method can be designed in such a way that the dynamic axial forces are control variables of a control, in particular worm speed control, and furthermore that for a worm speed control or a torque-dependent control, the torque on the worm is additionally used for signal acquisition.
  • the screw speed control can be carried out in addition to a drum speed control. It can also the static axial screw load can be kept constant by regulating, in particular, screw speed control.
  • the present invention further relates to a centrifuge with a screw which rotates in the same direction in an outer drum with a small gap and has an associated drive system for carrying out the method according to the invention.
  • This centrifuge is then characterized according to the invention by location-specific or sector-wise single or multiple force measuring arrangements arranged in the area of the screw for generating output signals as a measure of the axial forces occurring on the screw or components thereof, which output signals for generating control signals for the drive on a converter. and amplifier stage.
  • the centrifuge can then be designed such that the force measuring arrangements are electronic or hydrostatic sensors, respectively.
  • Axial bearing with axial force sensors resp. Include pressure gauges on hydrostatic thrust bearings.
  • the 1 comprises a conically tapering outer drum 1 in which a screw 2 rotates in the same direction with a small gap.
  • the outer drum 1 has a pronounced cylindrical part to increase the residence time, whereas the conical part throws the residue largely dry.
  • the worm 2 acts here due to a small speed difference of, for example, 2 to 70 rpm. as a conveying element for the deposited relatively dry residue.
  • the outer drum with 1410 U / Min. and the screw at 1370 rpm. circulate, which drive takes place via drive machine 3 and gear 4.
  • the suspension is fed through the hollow shaft 5 of the screw 2 approximately to the center of the drum space 6, for which there are radial openings 7 in the casing of the hollow shaft 5 of the screw 2.
  • the clarified liquid flows under the effect of the centrifugal separation to the further drum space and flows there over overflow edges 9 at the level of the pond surface 10 through openings 11 at the front.
  • the screw 2 conveys the residue deposited in the middle part of the outer drum 1 to the narrow cone end and ejects it there, largely dry-spun through openings 8.
  • the differential or screw speed is controlled by driving the drive machine 3 and / or gear 4.
  • Such axial forces Fa or Components can be measured locally (Fig. 2) or sectors (Fig. 3) by means of force measuring arrangement 12 on the helix 2 'of the screw 2, the output signal 13 of the force measuring arrangement 12 then using a converter and amplifier stage 14 for the feedback or.
  • Control signal 15 for the drive machine 3 delivers, as is indicated schematically in FIG. 4.
  • the acting axial forces Fa1, Fa2 can also be measured at several points on the screw 2 and the measured values can be obtained via force measuring arrangements 121, 122 as output signals 131, 132.
  • Such static axial forces can be used as a reference signal for the control.
  • the dynamic axial force thus provides information about the compression of the zone which is in the area of the local shell radius, the determined axial force forming an addition of the static axial force and the dynamic axial force while the screw is running.
  • the static axial force must be entered as a control default value, either as an empirical value or by periodic measurement with the screw at a standstill.
  • the screw speed is adjusted in the working point in such a way that the ratio of dynamic axial force to torque remains constant in the long term.
  • a regulation forces the centrifuge to have geometrically similar solid distributions even with variable solids loads and thus prevents repercussions in the regulation.
  • Such a regulation therefore permits stable running even when the sediments are highly compressed.
  • the screw speed can also be adjusted so that the differential quotient of the change in the total axial force and the change in the torque remains constant over a longer period of time.
  • the quotient of dynamic axial force and torque is a solid constant at the same drum speed and the same specific flocculant admixture and provides information about their compressibility or "screwability".
  • the worm speed control can also be carried out with a drum speed control. This allows over the additional Drum speed control to achieve a constant ratio of dynamic axial force and torque in order to counter fluctuations by changing the compressibility.

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  • Centrifugal Separators (AREA)
EP19910120887 1990-12-11 1991-12-05 Verfahren und Einrichtung zur Regelung einer Vollmantelzentrifuge Expired - Lifetime EP0490270B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH391990A CH682053A5 (enrdf_load_stackoverflow) 1990-12-11 1990-12-11
CH3919/90 1990-12-11

Publications (3)

Publication Number Publication Date
EP0490270A2 EP0490270A2 (de) 1992-06-17
EP0490270A3 EP0490270A3 (de) 1992-07-08
EP0490270B1 true EP0490270B1 (de) 1995-02-15

Family

ID=4266316

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910120887 Expired - Lifetime EP0490270B1 (de) 1990-12-11 1991-12-05 Verfahren und Einrichtung zur Regelung einer Vollmantelzentrifuge

Country Status (8)

Country Link
EP (1) EP0490270B1 (enrdf_load_stackoverflow)
JP (1) JP3308573B2 (enrdf_load_stackoverflow)
AU (1) AU648125B2 (enrdf_load_stackoverflow)
BR (1) BR9105336A (enrdf_load_stackoverflow)
CH (1) CH682053A5 (enrdf_load_stackoverflow)
DE (1) DE59104607D1 (enrdf_load_stackoverflow)
DK (1) DK0490270T3 (enrdf_load_stackoverflow)
RU (1) RU2072659C1 (enrdf_load_stackoverflow)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997020634A1 (en) * 1995-12-01 1997-06-12 Baker Hughes Incorporated Method and apparatus for controlling and monitoring continuous feed centrifuge
EP3689470A1 (en) 2017-06-15 2020-08-05 Alfa Laval Corporate AB Centrifugal separator and method of operating a centrifugal separator
DE102019126325A1 (de) * 2019-09-30 2021-04-01 Gea Mechanical Equipment Gmbh Vollmantel-Schneckenzentrifuge

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1431973A (fr) * 1964-04-17 1966-03-18 Alfa Laval Ab Organe détecteur pour la mesure d'une poussée
US3532264A (en) * 1968-10-15 1970-10-06 Bird Machine Co Centrifugal separation apparatus
US4070290A (en) * 1976-03-04 1978-01-24 Bird Machine Company, Inc. Centrifuge with torsional vibration sensing and signaling
GB1583517A (en) * 1977-05-04 1981-01-28 Jackson J F Solid bowl decanter centrifuges of the scroll discharge type
DE3115692A1 (de) * 1981-04-18 1982-11-11 Klöckner-Humboldt-Deutz AG, 5000 Köln Adaptives regelverfahren

Also Published As

Publication number Publication date
EP0490270A3 (de) 1992-07-08
DK0490270T3 (da) 1995-07-10
AU648125B2 (en) 1994-04-14
RU2072659C1 (ru) 1997-01-27
EP0490270A2 (de) 1992-06-17
JP3308573B2 (ja) 2002-07-29
JPH04267957A (ja) 1992-09-24
CH682053A5 (enrdf_load_stackoverflow) 1993-07-15
BR9105336A (pt) 1992-09-01
AU8885991A (en) 1992-06-18
DE59104607D1 (de) 1995-03-23

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