Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
  • B03B5/28—Washing granular, powdered or lumpy materials; Wet separating by sink-float separation
  • B03B5/30—Washing granular, powdered or lumpy materials; Wet separating by sink-float separation using heavy liquids or suspensions
  • B03B5/32—Washing granular, powdered or lumpy materials; Wet separating by sink-float separation using heavy liquids or suspensions using centrifugal force
• • 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
  • B04B2001/2041—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

Definitions

• the invention relates to a screw centrifuge for the wet mechanical separation of solid mixtures according to the preamble of claim 1.
• Such a wet centrifuge is known, for example, from EP-A 1 020 227.
• One of the two counter-rotating screws of the screw conveyor conveys the sediment thrown to the drum shell of the rotor to the discharge openings formed at one end of the rotor, while the other screw does so on the carrier liquid Floating, lighter floating material promotes to the discharge openings at the other conical end of the rotor.
• the liquid level of the carrier liquid is constant over the entire rotor length.
• the invention has for its object to provide a screw centrifuge of the type specified in the preamble of claim 1, in which it is possible to achieve mutually independent moisture contents for the sinking material and for the floating material.
• this object is achieved in that a radially inwardly projecting stowage device is arranged on the rotor for producing a different liquid level for the sinking material and the floating material.
• a sorting decanter is available that is practically composed of two decanters coupled to one another, with the heavier sink material being discharged in one decanter, while the lighter floating material is separated out in the other decanter. The two decanters are separated from each other by the stowage device that projects inwards.
• the screw centrifuge according to the invention is particularly suitable for separating plastics of different densities which are suspended in the carrier liquid, for example PVC or PA and PP.
• the stowage device consists of a retaining ring which leaves an annular gap to the shaft of the screw conveyor and behind which at least one overflow pipe for the carrier liquid is arranged in the conveying direction for the float, the radially inward inlet opening of which leaves a distance from the shaft of the screw conveyor.
• the overflow tube is radially adjustable to adjust the distance.
• the liquid level in the area of the screw for the discharge of the floating material can be set, whereby the length of the drying section for the floating material before the discharge and thus the residual moisture content of the floating material can be predetermined.
• the retaining ring has a channel profile which is U-shaped in longitudinal section and encompasses the overflow tube, consisting of a radial ring fastened to the rotor wall, a transition piece forming the channel profile base and an adjoining barrier wall, the free end of which has a small radial distance to the rotor wall.
• means for adjusting the annular gap are assigned to the storage ring.
• a longer drying section here also means a longer dwell time before discharge and thus a lower residual moisture content of the sediment.
• FIG. 2 shows an enlarged detail of area S of FIG. 1 with the stowage device
• FIG. 4 shows a variant of FIG. 2
• FIG. 5 shows a section in the plane V-V of FIG. 4,
• FIG. 6 shows a variant of FIG. 4,
• FIG. 7 shows a section in the plane VII-VII of FIG. 6,
• Figure 8 shows a variant of Figure 6
• the screw centrifuge has a rotor 10 which is composed of a central, cylindrical drum 12 and two conical drums 14 and 16 which are firmly connected to it. Two roller bearings 18 are used to mount the rotor 10 in a housing (not shown).
• a pulley 20 for rotating the rotor 10 about its horizontal axis 24 and a gear 22 are indicated.
• a screw conveyor 26 is mounted in the rotor 10 and is driven via the gear 22 at a different speed than the rotor 10 about the same axis 24.
• the screw conveyor 26 consists of a hollow shaft 28 on which two counter-rotating screws 30 and 32 are attached. The helix 34 of each of the two screws 30, 32 have openings 36 in the region of the shaft 28.
• the mixture to be separated and suspended in a carrier liquid is fed in the direction of arrow A in FIG. 1 by means of a standing or rotating feed tube (not shown) through the hollow shaft 28 into a chamber 38 which is formed in the central region of the shaft 28 and lead from the radial openings 40 into the space between the screw conveyor 26 and the rotor 10.
• discharge openings 42 are provided for the light phase (floating material), which are incorporated in a ring shape in the drum wall.
• discharge openings 44 for the heavy phase (sediment) are worked into the end of the conical drum 16 opposite.
• baffle plate 46 is fastened in the area of the cylindrical drum 12, which prevents the floating material from mixing back with the suspension.
• a radially inwardly projecting stowage device 48 is fastened to the rotor 10 and, in the exemplary embodiments, is arranged at the transition from the cylindrical drum 12 to the conical drum 14 on the left in FIG.
• the storage device 48 has the effect that a different liquid level 50 is generated for the floating material which is discharged via the discharge openings 42 than for the sinking material (liquid level 52) which support openings 44 is secreted at the right end of the rotor 10.
• the stowage device 48 consists of a baffle ring, generally designated 54, which has a channel profile which is U-shaped in longitudinal section. This channel profile is composed of a ring 56 which is fastened to the rotor wall 58 and protrudes radially inward therefrom, an axial transition piece 60 which forms the channel profile base and an adjoining barrier wall 62 which projects obliquely from the transition piece 60. An annular gap 64 is present between the transition piece 60 and the shaft 28 of the screw 30. The free end of the barrier wall 62 leaves a small radial distance 66 to the rotor wall 58 free.
• FIGS. 2, 4, 6 and 8 show that in the area of the retaining ring 54 on the rotor wall 58 four overflow tubes 68 are attached, which open into the U-shaped channel profile of the retaining ring 54 with their radially inward-pointing inlet openings 70.
• the overflow tube 68 can be adjusted in the radial direction by means not shown, which is indicated in FIGS. 2, 4, 6 and 8 by double arrows.
• the retaining ring 54 is firmly connected to the rotor wall 58 and has a bevel 72 in the region between the ring 56 and the transition piece 60.
• the suspension to be separated passes through the openings 40 of the hollow shaft 28 into the area of the cylindrical drum 12, where the liquid level 52 is determined by the annular gap 64, ie by the Distance of the transition piece 60 from the shaft 28 of the screw conveyor 26.
• the specifically heavier solid parts are thrown against the rotor wall 58 due to the centrifugal force exerted by the rotor 10, while the specifically slightly Float solid particles on the surface of the liquid level 52.
• the screw 32 transports the heavy phase (sediment) in FIG. 1 to the right in the direction of the discharge openings 44.
• a more or less long drying section 74 is formed at the end of the conical drum 16, at the beginning of which the solid parts lifted from the carrier liquid by the screw 32 and conveyed along this drying section 74 to the discharge openings 44.
• the specifically lighter floating material which floats on the liquid level 52 is conveyed via the radially smaller screw 30 in the opposite direction to the annular gap 64, the bevel 72 of the retaining ring 54 supporting the overflow of the floating material into the left conical drum 14.
• the liquid level 50 depends on the distance between the inlet opening 70 of the overflow tube 68 and the shaft 28 of the screw conveyor 26. If the overflow tube 68, starting from the example in FIG. 2, is adjusted radially outward, a part of the carrier liquid flows out through the overflow tube 68 until the new liquid level 50 is reached. As a result, the drying section 76 in the conical drum 14 on the left in FIG. 1 is increased, independently of the liquid level 52 for the sink material. Conversely, this drying section 76 is reduced when the overflow tube 68 is adjusted radially inwards.
• the annular gap 64 is closed off by an orifice 78 which has an orifice ring 80 which is formed in one piece with the ring 56 and extends radially from the ring 56 to the outer surface of the shaft 28 of the screw conveyor 26.
• overflow windows 82 are incorporated, evenly distributed over the circumference, the openings of which can be enlarged or reduced by weir plates 84.
• the weir plates 84 are radially adjustable from the outside by means not shown, so that the liquid level 52 in the cylindrical drum 12 and in the right-hand conical drum 16 is determined by the radial inner edge of the weir plates 84.
• the diaphragm 78 consists of two annular disks which can be rotated relative to one another, namely the diaphragm ring 80, which is also firmly connected to the ring 56 here, and an annular disk 86 located in the overflow direction, which is coupled to the screw conveyor 30 in a manner not shown and circulates with it.
• the aperture ring 80 has overflow windows 82; Similar overflow windows 88 are incorporated into the annular disk 86 rotating with the screw 30, so that when the screw 30 rotates, the floating material flows pulsating through the annular gap 64 into the conical drum 14.
• the diaphragm 78 likewise consists of two ring disks which can be rotated relative to one another, namely the diaphragm ring 80 and the ring disk 86 axially located in the conveying direction and which is attached to the ring 56.
• Both discs have overflow windows 82, 88 on their radial inner edge, which are triangular here and determine the throughflow opening for the floating material into the conical drum 14 as a function of their overlap.
• the annular disc 86 can be adjusted against the aperture ring 80, which is already done during the assembly of the centrifuge.

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• Centrifugal Separators (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 2002
  • 2002-03-20 DE DE10212187A patent/DE10212187A1/de not_active Withdrawn
• 2003
  • 2003-03-20 RU RU2004130860/12A patent/RU2315664C2/ru not_active IP Right Cessation
  • 2003-03-20 PT PT03709804T patent/PT1485205E/pt unknown
  • 2003-03-20 DE DE50307292T patent/DE50307292D1/de not_active Expired - Lifetime
  • 2003-03-20 CN CNB038115751A patent/CN1305578C/zh not_active Expired - Fee Related
  • 2003-03-20 EP EP03709804A patent/EP1485205B1/fr not_active Expired - Lifetime
  • 2003-03-20 AU AU2003214143A patent/AU2003214143A1/en not_active Abandoned
  • 2003-03-20 CA CA002479658A patent/CA2479658C/fr not_active Expired - Fee Related
  • 2003-03-20 WO PCT/EP2003/002907 patent/WO2003078070A1/fr active IP Right Grant
  • 2003-03-20 JP JP2003576116A patent/JP4575668B2/ja not_active Expired - Fee Related
  • 2003-03-20 ES ES03709804T patent/ES2287450T3/es not_active Expired - Lifetime
  • 2003-03-20 AT AT03709804T patent/ATE362399T1/de active
  • 2003-03-20 US US10/508,439 patent/US7153255B2/en not_active Expired - Fee Related

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