GB2108409A - Separating a medium into components of different particle masses - Google Patents

Abstract

Separation of a medium into components having different particle masses is effected by means of centrifugal force in turbulence free flow operated equipment, e.g. cyclones. The invention serves to reduce the friction resistance between a vortex and a chamber by removing part of a chamber wall or an entire chamber wall from between parallel vortexes. The supporting action of a chamber wall is compensated for by having parallel, oppositely rotating vortexes collide with each other at an angle of 0 to 90 DEG . Separators can be built up into large systems in which parallel vortexes are disposed e.g. in circular configuration or in a regular square net. Having the vortexes collide with each other further acts to develop a separating power intensifying radial oscillating motion in vortexes.

Description

SPECIFICATION A method of and apparatus for separating a medium into components of different particle masses This invention relates to a method and apparatus for separating a medium into components having different particle masses by means of centrifugal force in apparatus, e.g. cyclones, operating with free turbulence flow, in a mannerthatparticles having more mass concentrate during the rotation in the outer portions of a separating vortex and particles having less mass concentrate in those parts of a separating vortex which are closer to the centre of rotation.

The term "medium", as used hereinafter, is meant to cover powdered and fibrous flowing solid substances, flowing liquids, liquid drops and gases as well as mixtures thereof. The same way the term "particle" is meant to cover solid particles, liquid drops, liquid molecules, gas molecules or gas atoms. The term "separation chamber" is meant to coverva- rious turbulence chambers as well as flow pipes and flow chambers in which the separation is effected by means of centrifugal force.

Prior known are many different types of turbulence separator, such as cyclones having turbulence-limiting cylindrical and conical surfaces.

Usually a turbulence or whirl chamber has a smooth surface and the wall of a chamber is continuous in the direction of turbulent flow. By positioning such independently operated turbulence separators parallel to each other it has been possible to build e.g.

multicyclones. An example of such is disclosed in US Patent 3 747306. In addition, several Patent publications disclose turbulence separators in which two vortexes are tangentially connected to each other permitting the tangential passage of particles of certain size from one vortex to another. Also known is a turbulence system in which a medium to be separated is tangentially fed in between two vortexes. An example of this is disclosed in US Patent 4248 699.

A drawback with such prior turbulence separators is that centrifugal force pushes the medium vortex to be separated against the outside limiting surfaces.

Thus, friction will decelerate the running of a vortex and results in turbulence in the proximity of the walls. Friction and the resulting turbulence create considerable losses of energy. Due to the reduced rotational speed, the centrifugal force and therefore the separating power will be reduced. Furthermore, turbulence will re-mix some of the separation already effected. The prior art multicyclones require a lot of space and their structures have great mass.

Due to the losses caused by friction, it is difficult with the available turbulence separators to reach high turbulence velocities that are required for the separation of e.g. gases from gaseous mixtures.

Friction increases vigorously with the increase of velocity. Because of the braking effect caused by friction, a medium to be separated cannot stay in the rotation and thus subjected to effective separation for very long.

An object of this invention is to alleviate such drawbacks and that can be achieved by means of the method of the invention in a manner that two or more parallel separating vortexes are brought pairwise and sideways in contact with each other, so that the separating vortexes run into each other at an angle of 0 to 90 while rotating in opposite directions.

The equipment intended for carrying out the method of the invention is defined in appended claims.

The invention will now be illustrated by the following figures.

Fig. 1 shows a turbulence system of the invention in which the side by side disposed separating vortexes are pairwise and sideways in contact with each other.

Fig. 2 shows a turbulence system of the invention in which the vortexes are in the shape of an ellipse.

Fig. 3 is a side of a cyclone system of the invention.

Fig. 4 is a section along the line IV-IV in fig. 3.

Fig. 5 is an axial section of a cyclone system according to the invention.

Fig. 6 is a section along the line VI-VI in fig. 5.

Fig. 7 shows one embodiment of a flow divider axonometrically.

Fig. 8 shows another embodiment of a flow divider axonometrically.

Fig. 9 shows a cross-sectional variation of a flow divider in fig. 8.

Fig. 10 is a section along the axis of rotation on line X-X in fig. 8.

Fig. 11 is a side view of one arrangement of a tangential supply in fig. 6.

Fig. 12 is a perspective view of a cyclone system of the invention in which the vortexes are conical.

Fig. 13 shows axonometrically flow dividers in a cyclone system in which the vortexes are conical.

Fig. 14 is an axonometric view of a turbulence system of the invention in which there are no walls between the individual vortexes.

Fig. 15 is a section of a turbulence chamber system of the invention in which one turbulence chamber is peripherally surrounded by a plurality of other turbulence chambers.

Fig. 16 is an axonometric view of a cyclone system of the invention in which the supply of a medium is into the cyclone in the middle.

Fig. 17 is a cross-section of a centrifuge having peripherally around its centre of rotation a cyclone system of the invention.

Fig. 18 is an axial section along the line XVIII-XVIII in fig. 17.

Fig. 19 is an axial drawing in section of a cyclone of the invention in which the vortexes are conical and the walls between the vortexes are mostly omitted.

Fig. 20 shows in principle minor flow dividers and the vortexes in the proximity thereof.

Fig. 21 shows in principle vortexes with no flow divider provided.

The central subject matter of this invention is to reduce the contact between a separating vortex and a surface limiting said vortex on the outer periphery, the drawbacksof such contact thus beingelimin ated. For this end, part of the surface which limits the vortex on the outer periphery, or the entire surface, is removed. The support action of the surface urging the vortex inwards is compensated for by running two adjacent vortexes into each other during their rotation, whereby they urge each other inwards. The vortexes running into each other at a small angle do not create turbulence and the friction therebetween is essentially zero providing that the rotational speeds are equal.

A further object of the invention is to set a medium to be separate in radial oscillating motion in the vortex at the time the collisions occur. This radial oscillating motion contributes to the separation of particles having different masses. By arranging the collision poits at uniform distances from each other, it is possible to develop in the vortex a regular wave motion which propagates essentially in the direction of the radius of rotation and which alternately brings the medium particles to be separated closerto and further away from each other in the direction of the radius of rotation. An impact directed radially from the outer periphery to the inner periphery is capable of giving the light particles a higher speed towards the centre of rotation than that given to the heavy particles whose inertia as well as centrifugal force are greater.

The following figures show by way of an example some embodiments of the invention as well as illustrate the mode of operation of the invention. In reality, a great number of various embodiments are conceivable for the invention. The shapes and dimensions of the equipment according to the invention are chosen according to a given end use.

Experimental researches and theoretical studies can be used for assistance.

The following terminology is used for the components illustrated in the figures: 1. a surface defining the separation space towards the outer periphery 2. the travelling path of a separating vortex gener ally without oscillation effect 10. a separation space in which particles having different masses separate from each other, or a turbulence chamber 12. a tangential inlet pipe through which the particles to be separated enter the separation space 13. an axial outlet pipe for particles having a small mass after the separation 14. an axial outlet pipe for particles having a heavy mass after the separation 39. a flow separator for separating various vor texes from each other 40. a collision area where the separating vortexes run into each other 47. a lid for said turbulence chamber 48. an axial supply pipe 49. the centre of rotation of a separating vortex 60. a minor flow divider 490. the centre of rotation of a centrifuge.

Figure 1 shows a turbulence chamber system of the invention, wherein the individual turbulence chambers lie side by side in a regular square net.

Turbulence chambers or separation spaces 10 are laterally contacted with each other so that approximately half of the wall surface of central chambers is removed. At the area of a removed wall surface there is formed a collision area 40 wherein the vortexes of various chambers run into each other. In a case shown in the figure the number of vortexes is 4 x 4 but the turbulence chamber system can include an arbitrary number of vortexes 2 which are pairwise contacted with each other in lateral direction. In the example of figure 1 there will remain between the vortexes flow dividers 39 having 4-branched cross -section and varying sizes. Also the shape of flow dividers 39 can vary. For example, a wave-like shape enhances the oscillation.

Figure 2 shows a turbulence system of the invention in which the individual vortexes 2 are in the shape of an ellipse for intensifying the radial impacts. In the case shown in fig. 2 the longest diagonals of said ellipses are perpendicular to each other. Alternatively, the longest diagonals of an ellipse can be made parallel. Aturbulence system of the invention can also be built up by means of vortexes of some other shape, e.g. those resembling a rounded triangle, those resembling a rounded square etc.

In the side view shown in figure 3 there is depicted a cyclone system of the invention with 4 x 4 cyclones combined into a system or array of cyclones. The figure does not show any supply means for cyclones. The supply of a medium to be separated into the cyclones can be effected axially or tangentially.

In the case shown in fig. 3, the separated fractions exit in axial direction but tangential outlet arrangements are also possible.

The sectional view of a cyclone system shown in figure 4 depicts that the individual turbulence chambers 10 are of equal size. This is preferable in view of the impact forces in various vortexes becoming equal. In this case, the flow dividers 39 consist of four smooth sections of a cylindrical surface.

The section shown in figure 5 illustrates the tangential inlets 12 for a cyclone system, said inlets being arranged between the individual vortexes 2.

Figure 6 shows the corresponding tangential inlets 12 from above.

Figure 7 shows a flow divider 39 which in the flow directions of said vortexes is provided with channelshaped grooves with sharp ribs therebetween. By means of such a shape it is possible to modify the shape of an axial section of vortex 2 at various stages of the rotation. Within the collision area 40 of the individual vortexes 2 the interface of said vortexes is a plane, i.e. the axial section of vortex 2 is linear. As the particles arrive at a vortex divider 39 shown in figure 7, said particles are forced to partially move also in axial direction. Thus, the particles having different masses are more easily capable of passing by each other in desired directions of separation. The cross-sectional shape of a flow divider can also be e.g. a circle or ellipse.

In the type of a flow divider 39 shown in figure 8,9 and 10 the axial section is wave-shaped. Between the wave-shaped ridges there are recesses into which vortexes 2 are forced. The regular shaping of a vortex 2 in axial and radial direction improves the separation.

Figure 11 shows a detail of one possibility of arranging a tangential inlet 12 in the case illustrated in figures 5 and 6.

Figures 12 and 13 show one embodiment of arranging conical turbulence chambers. The width of a collision area 40 can be chosen as desired. Flow dividers 39 can be flat conical faces or they can be made wavy or corrugated in the travel direction of vortex 2 or grooved in axial direction.

Figure 14 shows an embodiment of the invention wherein the walls between the individual vortexes 2 are completely removed. Vortexes 2 are created and maintained by means of tangential inlets 12 effected between the vortexes 2 as directed by the arrows.

The individual vortexes 2 whirl at the same speed and in the same sizes and penetrate laterally into each other. Lateral friction between vortexes 2 is very little. In the case of figure 14 the centres of rotation 49 are parallel. The inlet or supply can also be effected axially.

Figure 15 shows a turbulence system of the invention wherein one major vortex 2 is peripherally surrounded by a plurality of minor vortexes 2. Within the collision area 40 the tangential speed of the major vortex 2 and those of the minor vortexes 2 are equal, the angular speeds of said minor vortexes 2 being higher. The centrifugal force of said minor vortexes 2 is decreased by a thinner rotating mass as compared to the major vortex 2 but, on the other hand, the centrifugal force of said minor vortexes 2 is increased by a smaller radius as compared to the major vortex 2. Thus, the vortexes 2 of different sizes are in balance as for the centrifugal forces. In the example of figure 15, the particle mass of said major vortex 2 will be subjected to 18 colliding impacts during one cycle.In figure 15, the collision areas 40 located in the outer parts of said major vortex 2 are in tangential direction made so as to have the same length as the sections between the collision points 40. Hence, the major vortex 2 is forced to regular wave motion.

Figure 16 shows a cyclone system of the invention wherein the cyclones are staggered in axial direction. The intake of a medium to be separated is effected into the uppermost central cyclone out of which particles can pass partially sideways into the cyclones in lower positions through collision areas 40. Passing into the lower cyclones is fraction concentrated in the upper section of a turbulence chamber 10 into particles having major mass. The heavy-mass particles concentrate mostly into the last, axially lowermost cyclones of a cyclone chains.

Obtained out of said cyclones located in axial direction at different levels are fractions of heavy and light masses and concentrated to various de greesthrough outlets 13; 14. Some of these can be re-passed into the central cyclone through an inlet pipe 12 for effective concentration. By the regulation of the sizes and pressure of the outlets 13; 14 of cyclones located at various levels it is possible to control the particle composition of various cyclones.

Accordingly, it is possible to build up cyclone systems or arrays wherein the central cyclone is surrounded by 3,4,5 etc. cyclones at regular intervals and the latter are extended by other cyclones.

Figure 17 shows a cyclone system of the invention as disposed in a centrifuge peripherally around a centre of rotation 490. The rotation of a centrifuge combined with the rotation of cyclones creates oscillating motion in the vortexes of cyclones, thus enhancing the separation. Oscillation is also increased by the fact that the adjacent vortexes collide with each other.

Figure 18 shows a centrifuge in axial section. The angle between the centres of rotation 49 of cyclones and that 490 of said centrifuge can vary according to the conicity or cylindricity of cyclones and the length of a desired collision area 40.

Figure 19 shows the symmetric position of the centres of rotation 49 of conical vortexes 2 relative to each other in axial section with the walls between individual vortexes removed from the uppers sections of vortexes 2. In this case, the position of the centres of rotation 49 in a square net is measured along a spherical surface 47.

Figure 20 illustrates a case in which four vortexes 2 has positioned therebetween two minor flow dividers 60 instead of one major flow divider 49. Thus, a friction surface defining the vortexes 2 will be smaller. Between vortexes 2 and the minor flow dividers 60 there will be counter-vortexes which support the separating vortexes 2 laterally.

Figure 21 shows the counter-vortexes forming between said separating vortexes in the event where are no flow dividers 39; 60 at all. The individual vortexes develop in a natural manner and reach internal balance. In reality, said vortexes can build up a very complicated entity.

Claims (1)

1. A method of separating a medium into components of different particle masses by means of centrifugal force in free turbulence flow operated equipment so that particles having heavier mass are concentrated during the rotary movement in the outer parts of a separating vortex and particles having lighter mass are concentrated in those parts of the separating vortex which are closer to the centre of rotation of the separating vortex wherein two or more separating vortexes disposed side by side are pairwise laterally contacted with each other, so that said separating vortexes collide with each other at an angle of 0 to 90" while rotating in opposite directions.

2. A method as set forth in claim 1, wherein said separating vortexes disposed side by side build up a turbulence system in which the centres of rotation make up a regular square net as seen in axial direction.

3. A method as set forth in claim 1, wherein said separating vortexes disposed side by side build up a turbulence system in which around one separating vortex there are peripherally disposed a plurality of other separating vortexes.

4. A method as set forth in claim 1, wherein said separating vortexes disposed side by side build up a turbulence system in which the centres of rotation of separating vortexes are positioned symmetrically relative to one of the centres of rotation;

5. An apparatus for carrying out a method as set forth in any one of claims 11-4, wherein turbulence chambers of parallel turbulence separators are pair wiso partially within each other building up collision aress with the colliding parallel vortexes rotating in GppGSite Ci--ections.

5. AturLlence separator as set forth in claim 5, "ih."ein suppiv of a medium to be separated is effected between said turbulence chambers into a collision ama.

7 A turbulence separator as set forth in claim 5, wherein said turbulence chambers are positioned in a regular square net parallel to each other.

1. i turbulence separator as set forth in claim 5, wherein one turbulence chamber is peripherally surrounded by other turbulence chambers.

A turbulence separator as set forth in any one claims 5-7, wherein chamber walls are omitted from between the parallel turbulence chambers.

10. A turbulence separator as set forth in any one of claims 5-7 wherein between four parallel turbulence chambers there is a flow divider of squareshaped cross-section.

11. A turbulence separator as set forth in any one of claims 5-7, wherein between four parallel turbulence chambers there are two minor flow dividers.

12. A turbulence separator as set forth in any one of claims 5-7, wherein between four parallel turbulence chambers there is a flow divider of circular cross-section.

13. A turbulence separator as set forth in any one of claims 10-12, wherein a flow divider is grooved in the propagating direction of a separating vortex.

14. Aturbulenceseparatorassetforth in claim 10, wherein a flow divider is corrugated in the propagating direction of a separating vortex.

15. A apparatus for carrying out the method as set forth in claim 3 or 4, wherein the adjacent turbulence chambers are staggered in the axial direction.

16. An apparatus for carrying out the method as set forth in claim 1, wherein the turbulence chambers of a turbulence separator are disposed peripherally around the centre of rotation of a centrifuge.

17. A method of separating a medium into components of different particle masses by means of centrifugal force, substantially as described herein with reference to, any one or more of the Figures of the accompanying drawings.

18. Apparatus for carrying out the method as claimed in claim 1 substantially as described herein with reference to, and as illustrated in, any one or more of the Figures of the accompanying drawings.