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
  • B04B2001/2083—Configuration of liquid outlets

Definitions

• the invention relates to a solid bowl screw centrifuge according to the preamble of patent claim 1.
• the device for adjusting the fluid level consists of a weir, which can be mechanically adjusted during operation.
• the mixture to be separated is fed via a static feed pipe into a feed chamber integrated in the screw body and from there into the working space of the centrifuge and subjected to a corresponding centrifugal acceleration on the basis of the drum speed.
• the usually specific heavier solid settles on the drum inner wall and is conveyed by the screw conveyor to openings at the end of the conical drum and thrown off.
• the clarified centrate, the light phase flows in the worm gear opposite to the solid transport direction and leaves the centrifuge via the weir opening.
• the known from DE 39 21 327 weir is adjusted for adjusting the liquid level via an axially displaceable ring and a deflecting member in the radial direction.
• a paring disc is arranged non-rotatably on the stationary during operation feed pipe, which is connected upstream of a throttle disk. Both discs can by means of a Electric drive can be adjusted axially.
• the throttle disk may be formed as a member rotating with the drum.
• the invention has for its object to simplify constructively in a worm centrifuge of the type specified in claim 1 type device for adjusting the liquid level while maintaining the possibility of level adjustment during operation.
• the means for adjusting the liquid level consists of a control means for braking or accelerating the liquid particles of the light phase, which is driven in rotation at a different speed of the drum rotation and leaves a through-flow annular gap to the drum inner wall.
• control element is designed as an immersion disk whose surface discontinuities can slow down or accelerate the liquid particles.
• the control element is designed as an immersion disk whose surface discontinuities can slow down or accelerate the liquid particles.
• As heat axially projecting ribs are possible from the immersion disk, but also slots or holes in the immersion disk, protrusions or surface roughening. These may be provided on one side or on both sides of the immersion disk.
• control it is possible to form the control as a vane rotor.
• the control can be attached to the hollow shaft of the screw conveyor, so that at the same time the speed of the control is connected with a change in the screw speed.
• control can be rotatably mounted on a hollow shaft stub of the rotor drum and with its own rotary drive in the form of a motor be connected.
• the rotary drive acts as an output for a generator.
• FIG. 1 shows the schematic, partially sectioned view of a screw centrifuge in a first embodiment of the invention
• FIG. 2 shows two communicating tubes with a liquid filling
• FIG. 3 shows the U-tube of FIG. 2 with two liquids of different density
• FIG. 4 shows the centrifuge shown in FIG. 1 with a drive motor for the control element
• FIG. 5 shows a variant of FIG. 4,
• FIG. 6 shows a further variant of FIG. 4,
• FIG. 7 shows a variant of FIG. 6 as a three-phase centrifuge
• FIG. 8 shows a further modified embodiment for the principle of FIG. 6,
• FIG. 9 shows an enlarged detail view from FIG. 8,
• FIG. 11 shows a detailed illustration from FIG. 10.
• FIG. 1 shows schematically a first embodiment of a solid bowl screw centrifuge 10 according to the invention.
• This consists in known manner of a rotor drum 12 which is supported at both ends in radial bearings 14 and rotatable about a horizontal axis 16 by a drive, not shown.
• the rotor drum has a cylindrical drum portion 18 and a conical drum portion 20.
• a screw conveyor 22 is rotatably mounted about the axis 16 at a speed deviating from the drum speed.
• the rotary drive required for this purpose is also not shown.
• the screw conveyor 22 consists of a hollow shaft 24, are mounted on the screw helix 26 for the transport of the heavy phase to discharge openings 28 in the conical drum section 20.
• a left-hand hollow tube stub 30 of the rotor drum 12 leads through a supply pipe 32, not shown in Figure 1 (see Figure 6), for the mixture to be separated (Feed suspension) axially into a formed in the hollow shaft 24 feed chamber 34, lead from the feed openings 36 in the working space 38 of the screw helix 26.
• the screw helix 26 conveys the specifically heavy phase (thick material), which assumes the height ho to the drum inner wall, into the conical drum section 20, from which it is discharged via the discharge opening 28.
• the liquid, light phase (centrate) with the height hp flows in the opposite direction to the end of the cylindrical drum portion 18 end wall 40, before which the control element 42 according to the invention is arranged.
• this consists of a radially oriented plunger 44, projecting from the axial ribs 46 in the direction of the end wall 40.
• the plunger 44 is attached here to a cylindrical ring 48 which is rotatably supported by two ball bearings 50 on the hollow shaft stub 30.
• the ring 48 At its end projecting from the drum 12, the ring 48 has a pulley 52 for the belt connection 54 with an electric motor 56 (see Figure 4).
• the pressure behaves as in a U-tube in which the Zentratteilchen initially flow radially to the drum inner wall 58 to then flow through the annular gap 60 and the overflow 62 in the end wall 40 to the outside.
• FIG. 3 shows a corresponding model of a rotating U-tube in the region of the control element 42 of FIG. At the apex applies to the pressures Pz of the centrate F (liquid phase) and P D of the thick material D (heavy phase):
• FIG. 1 shows the different angular velocities of the rotor drum and the control element cos.
• the angular velocity of the rotor drum determines the angular velocity of the liquid phase:
• the angular velocity cos of the control element 42 designed as a dip disk 44 with or without ribs 46 is approximately equal to the angular velocity of the thick material (heavy phase), but different from the centrate:
• the dip disk 44 of the control element 42 is designed without ribs 46, as shown in FIG. 11.
• a Zentratteilchen maintains the recorded on the inner wall of the drum 58 peripheral speed. This means that as the diameter decreases, the angular velocity of the centrate particle must increase. The centrate rushes ahead of the surrounding drum wall. By increasing the angular velocity, the centrifugal acceleration z and thus the fluid pressure in the gap 60 between the immersion disk 44 and the drum inner wall 58 increases. In this gap, the pressure behaves as in the U-tube of Figure 2, d. H. from the liquid columns on both sides of the dip disk 44, the same pressure is generated.
• the pressure balance can only be achieved by increasing the height of the liquid column in the working space 38 of the centrifuge. In extreme cases, this can lead to an undesirable overflow of liquid through the solids discharge 28.
• Case 2 corresponds to the sketches shown in FIGS. 6, 7, 8, 9, according to which the dipping disc 44 is fastened on the hollow shaft 24 of the screw conveyor 22 and provided with ribs 46 on its side facing the end wall 40.
• a Zentratteilchen has first recorded on the drum inner wall 58 peripheral speed. As the diameter decreases, the centrate particle becomes the radius and the screw speed imposed corresponding peripheral speed. (The screw speed differs only insignificantly from the drum speed). This means that as the diameter decreases, the angular velocity of the centrate particle remains unchanged. The centrate has about the same angular velocity as the surrounding drum wall. As a result, there is no undesired leveling of the centrifuge working space 38 by the U-tube effect (the density of the liquid and the centrifugal acceleration are the same).
• the third case corresponds to the representation in FIG. 4, according to which the control element 42 with the immersion disk 44 provided with ribs 46 can be driven by a motor 56 (or braked by a generator) relative to the drum speed.
• the control 42 as outlined in Figure 5 as a rotor 64 with i. w. radially aligned wings 66 may be formed.
• the brake case will be explained below; the drive case is correspondingly reversed.
• the Zentratteilchen enters with the recorded on the drum inner wall 58 peripheral speed in the gap 60 between plunger 44 and end wall 40 a.
• the centrate particles are approximately forced to the speed of the immersion disk 44 or wing 66.
• the peripheral speed of the Zentratteilchens is decelerated according to the speed of the plunger or vanes and the diameter considered.
• the braking energy is converted into electrical energy in the generator.
• the centrifugal acceleration acting on the centrate particle is reduced.
• the equilibrium condition in the gap 60 between plunger 44 and drum inner wall 58 adjusts itself by a reduction of the liquid level in the working space 38 of the centrifuge.
• a partition wall 68 to the working space 38 of the centrifuge is required.
• FIG. 7 shows a three-phase version of the centrifuge with circumferentially distributed, radially adjustable overflow tubes 72 for discharging a light liquid.
• the discharge openings 70 for the discharge of a heavy liquid can be closed by screws 74.
• the solids are discharged via the discharge opening 28.
• FIGS. 8 and 9 are comparable to the version of FIG. 7, in which the immersion disk 44 is fastened to the hollow shaft 24 of the screw conveyor 22 and provided with ribs 46.
• FIG. 9 one of the screws 74 for closing the discharge opening 70 in the immersion disk 44 can be clearly seen.
• FIGS. 10 and 11 once again show a version with immersion disk 44 without ribs.
• the means for decelerating or accelerating the liquid particles may consist of other surface discontinuities, e.g. As roughening or protrusions.

Applications Claiming Priority (2)

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• 2012
  • 2012-03-22 DE DE102012102478A patent/DE102012102478A1/de not_active Withdrawn
• 2013
  • 2013-03-21 WO PCT/EP2013/055956 patent/WO2013139920A2/de active Application Filing
  • 2013-03-21 JP JP2015500929A patent/JP2015510840A/ja active Pending
  • 2013-03-21 CA CA2868195A patent/CA2868195A1/en not_active Abandoned
  • 2013-03-21 CN CN201380015556.1A patent/CN104302405A/zh active Pending
  • 2013-03-21 US US14/378,623 patent/US20150018190A1/en not_active Abandoned
  • 2013-03-21 EP EP13717724.2A patent/EP2827996A2/de not_active Withdrawn

Non-Patent Citations (1)

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