EP3618968A1 - Decanter centrifuge - Google Patents
Decanter centrifugeInfo
- Publication number
- EP3618968A1 EP3618968A1 EP18778950.8A EP18778950A EP3618968A1 EP 3618968 A1 EP3618968 A1 EP 3618968A1 EP 18778950 A EP18778950 A EP 18778950A EP 3618968 A1 EP3618968 A1 EP 3618968A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- drum
- decanter centrifuge
- helix
- screw
- outlet
- 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.)
- Withdrawn
Links
Classifications
-
- 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
-
- 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
- B04B2001/2033—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 with feed accelerator inside the conveying screw
-
- 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
- B04B2001/2041—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 with baffles, plates, vanes or discs attached to the conveying screw
-
- 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
- B04B2001/2058—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 with ribbon-type screw conveyor
Definitions
- the invention relates to a decanter centrifuge with a rotatably drivable drum which tapers conically towards a solids outlet and forms at the opposite end a liquid outlet, a stationary inlet pipe axially leading into the drum for feeding a suspension into the interior of the drum, and a rotary drivable the drum arranged screw, which surrounds an outlet end of the inlet pipe and forms a coil which extends radially to the inner peripheral surface of the drum zoom.
- Decanter centrifuges of this type are used for the separation of mixtures, which usually consist of a solid and a liquid phase. However, there are also applications where there are two liquid phases and one solid phase. The mixtures are referred to here without restriction of the general public as "suspensions".
- An example of a decanter centrifuge of this type is described in JP. Hermeler, L. Horstkötter, T. Hartmann, "New Decanter Generation with Improved Energy Efficiency", F & S Filtration and Separation, Volume 26 (2012) No. 3.
- the suspension is pumped into the centrifuge via the central, standing inlet pipe, where is formed by centrifugal force a liquid ring, a so-called "pond” on the inner peripheral wall of the drum.
- the screw has the function of bringing the suspension from the center to the outside in the liquid ring and thereby to accelerate the peripheral speed of the screw and the drum. Due to the centrifugal force, the heavier particles separate on the inner wall of the drum. Due to a small speed difference between the screw and the drum, the solid is transported through the helices of the screw to the solids outlet. Ultimately, the solid cake is pushed out of the liquid ring and discharged through outlets in the drum shell. At the same time, the clarified liquid on the opposite side of the drum flows over the liquid outlet.
- the screw In the region of the outlet end of the inlet pipe, the screw forms a structure which is referred to as a distributor and has the function of accelerating the suspension to the peripheral speed of the screw.
- a distributor In the region of the outlet end of the inlet pipe, the screw forms a structure which is referred to as a distributor and has the function of accelerating the suspension to the peripheral speed of the screw.
- a radial component of velocity which is as small as possible should be generated, since the radial velocity component leads to high turbulences in the liquid ring and adversely affects the separation efficiency of the centrifuge.
- manifolds are used depending on the properties of the suspension differently designed manifolds are used.
- the object of the invention is to provide a decanter centrifuge with improved separation efficiency and reduced maintenance requirements.
- the inlet pipe is thus not surrounded by a closed screw body, on which solids could be deposited asymmetrically. Rather, the solids are removed through the spaces between the star-shaped support walls radially to the peripheral wall of the drum and then discharged through the screw.
- the arranged in radially and axially oriented planes supporting walls give the screw a very high bending stiffness, which further improves the smoothness and the formation of vibrations is suppressed.
- the radial support walls can support or even replace the function of the distributor by forcing an acceleration of the suspension in the circumferential direction.
- a further advantage of the invention is that the axial channels formed in the spaces between the star-shaped support walls in the region of the liquid ring, which allow a direct axial outflow of the clarified liquid to the liquid outlet, whereby due to the comparatively large flow cross-section of these channels a low flow velocity the liquid and thus a further reduction of turbulence and a corresponding improvement of the deposition behavior is achieved.
- the height of the helix in the longitudinal section, in which the helix is held on the radial support walls is smaller than the radial dimension (the pond depth) of the liquid ring, which is determined by an annular weir at the liquid outlet.
- the helix in a conical section of the screw which is located further to the solids outlet, can be designed as a full helix, which occupies virtually the entire radial clearance between the conical circumferential wall of the drum and a possibly also conical inner shell of the screw.
- the screw in this section can also be designed as a column screw or as a combination of column screw and full helix.
- the two sections of the screw can optionally be welded or screwed together.
- a suitable distribution structure can be integrated, which can be optionally used for the screw connection of the two screw sections.
- Conceivable distribution structures are, for example, a baffle arranged at a distance from the mouth of the inlet pipe on the axis thereof, a so-called rib distributor with radially arranged around the axis of the inlet pipe around ribs, whose number can also be greater than the number of support walls, a hole distributor with holes in the Circumferential wall of an end portion of the inlet pipe or a separate, adjoining the inlet pipe distributor body, or a pin distributor with a plurality of arranged in the axial direction of the drum bolts which are arranged at equal angular intervals around the axis of the inlet pipe and at the same time for a detachable screw connection between the star-shaped structure the supporting walls and the conical screw section can be used.
- the star-shaped support walls are connected to each other by disk-shaped, oriented at right angles to the drum axis support rings.
- the torsional rigidity of the structure formed by the supporting walls is increased.
- Fig. 2 is a section along the line II-II in Fig. 1st
- the decanter centrifuge shown in Fig. 1 comprises a drum 10 which is axially divided into a cylindrical portion 12 and a conical portion 14 and is terminated at both ends by respective hubs 16, 18.
- a screw 20 is arranged, which, like the drum, is divided into a cylindrical section 22 and a conical section 24.
- the worm on an inner shell 26 which is closed to the cylindrical portion through an end wall 28 and carries on its outer periphery a helical coil 30 which extends to the inner surface of the cylindrical portion 14 of the drum.
- the cylindrical portion 22 of the screw has a helical coil 32, which has a lower height than the coil 30 and is supported with its inner periphery on the axially extending outer edges of support walls 34 which extend in the axial direction of the drum and a star shape around the axis of the drum are arranged around.
- the cylindrical portion 22 of the screw is mounted with a bearing 36 on the hub 12 and the inner shell 26 of the conical portion 24 is mounted with a bearing 38 in the hub 18.
- the hub 12 of the drum is in turn mounted with a bearing 40 rotatably in a housing, not shown. Another not shown bearing serves to support the drum 10 at the opposite end.
- By not shown rotary actuators, the drum 10 and the screw 20 are driven at slightly different speeds.
- An inlet pipe 42 extends coaxially through the hub 12 and terminates inside the cylindrical portion 12 of the drum.
- An outlet end 44 of the inlet pipe 42 is surrounded at a small distance from the radially inner longitudinal edges of the support walls 34.
- the support walls 34 are interconnected by disc-shaped stiffening rings 46.
- One of these stiffening rings also serves as a holder for a rotationally symmetrical, centered on the axis of the drum baffle 48, which is arranged at a distance in front of the mouth of the inlet pipe 42.
- the support walls 34 are welded to the inner shell 26 of the conical portion 24 of the screw and to the stiffening rings 46 and a housing of the bearing 36, so that a bending and torsion-resistant support structure for the helix 32 is formed.
- the star-shaped arrangement of the support walls 34 can be seen, which preferably consist of a sheet having a thickness of for example 16 mm and are chamfered on the inner longitudinal edges each on one side.
- the drum 10 and the screw 20 are driven at slightly different speeds so that the screw 20 runs slightly faster than the drum 10.
- An emulsion to be decanted is pumped via the inlet pipe 42 into the interior of the drum 10 and through the baffle 48 radially outward distracted.
- the radial support walls 34 By the radial support walls 34, the emulsion is accelerated in the circumferential direction, so that it spreads due to their inertia on the leading surface of each support wall into a thin film and flows radially outwardly due to the centrifugal force.
- the radial component of the flow rate of the suspension remains relatively low due to the friction on the support walls 34.
- the suspension collects into a liquid ring or "pond" whose inner surface is shown in phantom in the upper half of Fig. 1. Due to the centrifugal force, the heavier solid phase of the suspension settles on the inner surface from the drum and, due to the differential rotation of the screw and drum, is driven by the helix 32 to the left in Fig. 1, ie toward the conical end of the drum Slit 52 of the baffle plate 50 is pressed into the conical portion 24 of the screw and then taken from the coil 30 and transported to the tapered end of the conical portion 14 of the drum, where it is discharged through a formed by radial discharge openings solids outlet 54.
- the hub 12 at the right end of the drum 10 is interrupted by openings 56, which together with an annular weir 58 form a liquid outlet 60.
- the inner diameter of the weir 58 determines the position of the inner surface of the liquid ring.
- the clarified liquid flows in a slow, steady axial flow into the interspace. men between the support walls 34 to the liquid outlet 60.
- the flowing liquid is only very little swirled, so that the solid phase can be deposited very effectively.
- the torsional stiffness of the support structure for the coil 32 can be increased by increasing the outer diameter of one or more of the stiffening rings 46, possibly to the inner surface of the liquid ring or, if you accept a small detour of the liquid over the interstices of the coil 32 in purchasing , even to the inner diameter of the helix 32nd
Landscapes
- Centrifugal Separators (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP17198929.6A EP3476488A1 (en) | 2017-10-27 | 2017-10-27 | Decanter centrifuge |
PCT/EP2018/077016 WO2019081177A1 (en) | 2017-10-27 | 2018-10-04 | Decanter centrifuge |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3618968A1 true EP3618968A1 (en) | 2020-03-11 |
Family
ID=60190738
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP17198929.6A Withdrawn EP3476488A1 (en) | 2017-10-27 | 2017-10-27 | Decanter centrifuge |
EP18778950.8A Withdrawn EP3618968A1 (en) | 2017-10-27 | 2018-10-04 | Decanter centrifuge |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP17198929.6A Withdrawn EP3476488A1 (en) | 2017-10-27 | 2017-10-27 | Decanter centrifuge |
Country Status (2)
Country | Link |
---|---|
EP (2) | EP3476488A1 (en) |
WO (1) | WO2019081177A1 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110252523B (en) * | 2019-05-10 | 2024-06-07 | 浙江工业大学 | Horizontal screw centrifuge |
DE102019135226A1 (en) * | 2019-12-19 | 2021-06-24 | Flottweg Se | Inlet area of a centrifuge screw and solid bowl screw centrifuge |
CN111517365B (en) * | 2020-06-10 | 2022-08-02 | 攀钢集团攀枝花钢铁研究院有限公司 | Titanium tetrachloride production method and system |
EP4272870A1 (en) | 2022-05-05 | 2023-11-08 | Hermeler, Jürgen | Decanter centrifuge |
EP4295957A1 (en) | 2022-06-24 | 2023-12-27 | Hermeler, Jürgen | Decanter centrifuge |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR384326A (en) * | 1907-11-25 | 1908-04-04 | Wilhelm Holzer | Centrifugal apparatus |
US5354255A (en) * | 1992-12-17 | 1994-10-11 | Alfa Laval Separation Inc. | Decanter centrifuge with conveyor capable of high speed and higher flow rates |
JP2003093923A (en) * | 2001-09-26 | 2003-04-02 | Asutemu Eng:Kk | Centrifugal separator |
-
2017
- 2017-10-27 EP EP17198929.6A patent/EP3476488A1/en not_active Withdrawn
-
2018
- 2018-10-04 EP EP18778950.8A patent/EP3618968A1/en not_active Withdrawn
- 2018-10-04 WO PCT/EP2018/077016 patent/WO2019081177A1/en unknown
Also Published As
Publication number | Publication date |
---|---|
WO2019081177A1 (en) | 2019-05-02 |
EP3476488A1 (en) | 2019-05-01 |
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Legal Events
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