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

Definitions

• the invention relates to a solid bowl screw centrifuge for clarifying or separating a liquid-solid mixture with a drum, at one end of which solid discharge openings are provided, with a rotating screw conveyor arranged at this end with a differential speed, the spirals of which are arranged on the convey solid matter settling the inner surface of the drum to the solids discharge openings, and the inner surface of the drum being formed by a lining, the design of which brings about an improved friction effect between the solid matter and the inner surface.
• Such a screw centrifuge is known, for example, from DE-PS 11 97 812.
• the lining is provided with a large number of parallel strips which extend in the direction of the drum axis.
• the known lining does indeed increase the frictional effect between the inner surface and the solid and thus prevents the solid from migrating with the screw conveyor, but the production of this lining is quite complex.
• the use of linings is not advantageous for all products.
• the known lining is disadvantageous because of the necessary distance between the screw blade and the inner surface of the lining.
• the use of linings for sanitary reasons is also not desirable.
• the gap increases by the height of the strips and the material thickness of the lining. With such a large gap, it is then inevitable that, after the lining has been removed, a screw conveyor with a larger outside diameter will be installed in the drum, so that proper conveyance of solids by the screw conveyor is ensured.
• the object of the invention is to design the known screw centrifuge in such a way that both the production outlay and the overall thickness of the lining are considerably reduced.
• This object is achieved in that the lining is provided with a large number of openings.
• the friction effect is improved by the thrown off solid itself, which initially settles in the openings in the lining. This creates a surface formed by the solid in the area of the breakthroughs, through which the subsequent solid is conveyed through the screw conveyor.
• the friction effect between the solid particles is greater than the friction effect between the screw and the solid, so that a migration of the solid with the screw is prevented.
• the openings are provided only in a partial area of the lining.
• the breakthroughs are only envisaged in the critical area. This avoids an undesirably high torque between the screw conveyor and the drum.
• the lining consists of several lining sections. This makes it easy to combine lining sections with or without openings.
• the gap between the inner surface of the drum and the diameter of the screw conveyor only has to be relative small material thickness of the sieve or perforated plate used is chosen larger, so that in many cases the same screw conveyor can be used even after the lining has been removed from the drum.
• Fig. 1 shows a partial section of the screw centrifuge
• FIG. 2 shows the detail “X” according to FIG. 1
• FIG. 1 in FIG. 1 denotes the drum, the inner surface of which is formed by a removable lining 2, which consists of several separate lining sections 3, 4 and 5.
• a screw conveyor 6 rotating at a differential speed, the spirals 7 of which convey the solid settling on the inner surface of the lining 2 to the solids discharge openings 8.
• the lining 2 has a plurality of openings 9. hen is, the contours can be formed arbitrarily, for. B. circular, slit-like or diamond-shaped.
• the openings 9 can also be provided only in the delivery-critical area, which is located in the lining section 4.
• the lining sections 3 and 5 would be smooth in this case.
• the solid that settles in the drum 1 initially fills the openings 9 and thereby forms a solid layer in the area of the openings 9 that rotates positively with the drum 1.
• the solid that continues to settle must pass through the coils 7 of the screw conveyor 6 via this solid layer axially conveyed away in the direction of the discharge openings 8.
• the high coefficient of friction between the positively deposited solid layer and the conveyed solids prevents the solid from migrating with the screw conveyor in the circumferential direction.
• the coefficient of friction generated on the inner surface of the lining 2 can be varied by the choice of the shape of the openings 2 and their total area in relation to the inner surface of the lining. As a result, the required screw torque can be kept low.

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• Centrifugal Separators (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=6420322

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Citations (4)

• 1990
  • 1990-12-14 DE DE19904039953 patent/DE4039953C1/de not_active Expired - Lifetime
• 1991
  • 1991-10-29 WO PCT/EP1991/002041 patent/WO1992010299A1/de not_active Application Discontinuation

Patent Citations (4)

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