Method and device for separating particles and fluids, as stated in the introduction to claim 1 and 3 respectively. It can be used e. g. for separating mineral fractions from suspensions.

Background It is known to introduce mixtures of particles and fluids to a rotating cup shaped container, to separate the particles and the fluid fraction. Further it is known to provide such containers or receptacles with grooves in the wall. Such known devices have a limited capacity, both in regard to output and in regard to separating ability. They have to be shut down for cleaning, which makes the use bothersome and reduces the capacity.

An alternative is a complicated design with valves which can be operated for emptying the particle fraction.

Objects The main object of the invention is to provide a method and a device which is less complicated in design and use than known devices. It should provide for operating continuously and give the necessary efficiency both in respect of capacity and separating ability. It should also have a favourable price compared to existing devices.

The invention The invention is defined in claims 1 and 3. With this method and apparatus various advantages relative to the prior art are achieved, which will be described in more detail in the following. In claims 2 and 4-15 various advantageous features are described. To increase the separation, oscillating rotation is provided. A further gain is achieved by having steps along the helical groove or grooves.

Separation is due to difference in specific weight between the particles and the fluid. The helical groove and the possible steps along the helical groove and/or the tangential oscillation additionally, increase the separating efficiency.

The invention can be used for different substances, in particular for separating particles from fluid, e. g. in enrichment of minerals and metals. The device can separate particles with different specific weights and separate fluids with different specific weights, which are not mutually soluble.

During the rotation, the bottom receptacle will accelerate introduced suspension or other matter up to the velocity of the receptacle and start the separating activity under the influence of the centrifugal forces. The heaviest particles are forced to the bottom of the groove.

The device acts like a centrifuge and will be able to increase the G-force up to 1200 times normal gravitational force.

The oscillating rotation will accelerate the mass of the groove or the grooves tangentially in a cyclic way and thus provide a relative movement between the mass and the walls of the groove.

If the mass, e. g. a suspension, is additionally moved over steps, the various parts are subject to different gravitational forces. This will enhance the separation process and provide for better separation. This will be repeated at each step. hi this way, the mass added will be"turned"helically along the main part of the centrifugal receptacle. The particles move slower as the conicity of the receptacle diminishes. At the same time the centrifugal force will increase. Together this will provide for better separation of the different parts of the substance, e. g. particles from fluid.

Outlets or release openings are provided at the upper part of the receptacle with the helical groove. These openings can be connected to valves.

Example The invention is further described with reference to the drawings, wherein Fig. 1 shows a sectional side view of a separation receptacle in accordance with the invention, Fig. 2 shows a partly sectional top view of the receptacle of Fig. 1, Fig. 3 show a section of a groove in the receptacle of Figs. 1 and 2, Fig. 4 shows a perspective view of a section of the receptacle wall Fig. 5 shows a part of a groove in a longitudinal section, with a substance being separated, and Fig. 6 shows schematically alternative groove profiles A-C in section.

Fig. 1 shows a separation receptacle 11 carried on a drive shaft 12 attached to or integrated with the receptacle bottom 13. The separation receptacle 11 consists of a lower cup shaped bottom part 14 for inlet of a substance to be separated, and an upper separation part 15 which is assembled from several conical sections of metal sheet, to be substantially parabolic. The separation receptacle 11 is rotated in the direction 17.

The bottom part 14 is divided into four chambers 16 with two perpendicularly intersecting bottom walls 18 and 19 which extend to the top of the bottom part. The purpose. of this part of the separation chamber is to receive the substance, e. g. the suspension, to be separated, and accelerate it to the same rotational velocity as the lower edge of the separation part 15. This will be further described.

The separation part 15 is provided with a helical groove 20 extending to the top of the receptacle. Groove 20 ascends against the rotational direction 17 of the separation receptacle 11.

Details of the groove 20 will be apparent B-om the following description.

A vertical, downward inlet tube 22 extends into the interior of the receptacle for introduction of the substance which is to be separated. At the upper edge the separation receptacle 11 is provides with a radial rim 23 with a downward flange 24. The purpose of this feature is to simplify the integration of the separation receptacle 11 in a housing suitable for collection.

The groove 20 is provided by inserting a profiled ribbon 25 of suitable plastic material, e. g. polyure thane, which is suitably fastened to the wall 26. The wall can also be manufactured with an integrated groove 20, e. g. by moulding.

The separation receptacle 11 is assembled from multiple conical wall sections to form a mainly parabolic shape.

Fig. 2 shows details of the groove 20. It is provided with steps 27 in the side walls, transverse to the rotational direction 17. In the example, 40 steps 27 are provided, but the number of steps can be lower or higher, e. g. between 30-50. At suitable distances, outlet openings 28 extending from the bottom of the groove 20 are provided through the wall 26. The openings 28 will pass heavy particles 29 separated from the substance. Separated particles are collected in a housing (not shown) enclosing the separation receptacle 11. Correspondingly, residual substance 30 of lighter particles and fluid are collected at the top of the separation receptacle 11.

Fig. 3 shows a section through a groove 20 at an outlet opening 28.

Fig. 4 shows a section on line B-B in Fig. 2, which illustrates the course of the groove 20 with steps 27 in the side walls, Fig. 5 shows the longitudinal part of the bottom of a part of the groove 20, with steps 27 which are separated by inclined side wall segments. The outlet openings 28 are approximately 30° inclined to a tangent m the outlet region, to direct the outlet opening toward the direction of movement. This inclination can vary between 5'and 45', The outlet openings 28 are mainly in the upper part of the receptacle. The openings 28 can be provided with valves to pass different factions of fluid and/or particles. Such valves can be opened and closed manually or by prior art remote control.

Fig. 6 shows three examples of alternative embodiments of the groove 20, viz. A) with V- shape, B) with U-shape and C) with a combination of a straight and on arcuate side wall, to give the groove an arcuate bottom. The steps can be on the bottom of the groove or on the whole or a part of the sidewalls.

The separation receptacle 11 is operated by the shaft 12. To have oscillating rotation, it can be connected to a motor over oval gears or a pulley drive with oval disks. It is also possible that an ercentric journalling can provide an oscillating effect in connection with helical grooves, e. g. with steps, combined with or replacing rotational oscillating.

Function The oscillating rotation of the separation receptacle 11 will provide cyclical tangential accelerating and retarding which promotes mutual movement between particles and/or fluid components with different specific weight. This will initiate the improvement in separation efficiency.

The stepped course of the sidewalls of the groove 20 will bring about further oscillation of the substance being fed for separation this further oscillation being superposed over the oscillation due to the rotation. This additional oscillation in such a string of substance in the groove will promote the separation of fluid and particles, influenced by the centrifugal force. In this way, a heavy fraction of particles will concentrate at the bottom of the groove 20 and be transferred therefrom through the outlet openings 28 or separated from lighter particles, fluid and other residues over the edge of the separation receptacle.

Modifications The invention is open to embodiments other than those describe above. More than one groove can be provided in the wall 26 or the grooves can be provided with or without steps with different design and gaps.

The invention can be used for separating different mixtures and substances, both with one or more different particles and/or one or more different unsoluble fluids. The separation effect will depend on the difference in specific weight.