OA21428A

OA21428A - Rotor of gas dispersion arrangement.

Info

Publication number: OA21428A
Application number: OA1202300474
Authority: OA
Inventors: Matti Luukkonen; Timo HÄMÄLÄINEN
Original assignee: Metso Finland Oy
Priority date: 2021-05-28
Filing date: 2022-05-27
Publication date: 2024-06-05

Abstract

A rotor (100) of a gas dispersion arrangement, comprising a cover disc (1), air slots (2) arranged to protrude away from the cover disc (1), the air slots (2) defining an interior space (3) in the interior of the rotor, an air channel (4) connected to the air slot (2) for supplying air to be dispensed in slurry, and slurry slots (5) arranged between and an alternating way with the air slots (2) around the interior space (3). The slurry slots (5) are in fluid communication with the interior space (3), and radially extending blades (6) arranged for separating the air slot (2) from adjacent slurry slots (5). The cover disc (1) comprises at least one through-hole (7) extending from an upper surface (8) of the cover disc to at least one of the slurry slots (5) .

Description

ROTOR OF GAS DISPERSION ARRANGEMENT

BACKGROUND

The invention relates to a rotor of a gas dispersion arrangement, such as a flotation cell.

Gas dispersion arrangements, such as flotation cells, may be used for e.g. recovering valuable ingrédients, such as métal concentrâtes from a slurry. Air is needed in a flotation cell for creating a froth bed. Typically, the air 10 is fed to a rotor through a duct arranged to the shaft of the rotor. When rotating the rotor, air is fed into the slurry, and air bubbles are dispersed therein. Air bubbles flow upwards and enter the surface of the slurry where they form the froth bed. Particles containing valuable in15 gredients may flow upwards with the air bubbles and enter in the froth bed. Alternatively, valueless ingrédients flow upwards with the air bubbles and enter in the froth bed, and the valuable ingrédients remains non-flotated.

Although the known rotors are resuit of vigorous research and development work, there are still needs for even more effective rotors in the field of gas dispersion arrangements.

BRIEF DESCRIPTION

Viewed from a first aspect, there can be provided a rotor of a gas dispersion arrangement, comprising a cover dise, ' air slots arranged to protrude away from the cover dise, the air slots defining an interior space in the interior , of the rotor, an air channel connected to the air slot for 30 supplying air to be dispensed in slurry, slurry slots arranged between and in an alternating way with the air slots around the interior space, the slurry slots being in fluid communication with the interior space, radially extending blades arranged for separating the air slot from 35 adjacent slurry slots, wherein the cover dise comprises at

least one through-hole extending from an upper surface of the cover dise to at least one of the slurry slots.

Thereby a rotor of a gas dispersion arrangement utilizing 5 downflow in a flotation cell and providing increased rotor pumping performance may be achieved.

The rotor is characterised by what is stated in the independent claim. Some other embodiments are characterised by 10 what is stated in the other claims. Inventive embodiments are also disclosed in the spécification and drawings of this patent application. The inventive content of the patent application may also be defined in other ways than defined in the following claims. The inventive content may 15 also be formed of several separate inventions, especially if the invention is examined in the light of expressed or • implicit sub-tasks or in view of obtained benefits or benefit groups. Some of the définitions contained in the following claims may then be unnecessary in view of the sepa20 rate inventive ideas. Features of the different embodiments of the invention may, within the scope of the basic inventive idea, be applied to other embodiments.

In one embodiment, the through-hole has a shape of a poly25 gon, such as quadrangle.

An advantage is that the through-hole or its side wall may create a pumping effect, i.e. act as a blade, and push slurry towards the slurry slot, thereby further increasing 30 rotor pumping performance.

In one embodiment, the through-hole comprises at least one side edge on the upper surface that makes a hole angle with radial direction of the rotor, wherein said hole an35 gle is in range of -10 ° - +45 ° .

An advantage is that an increased rotor pumping performance may be provided, and blockage of the through-hole may be prevented.

In one embodiment, an outmost wall of the through-hole makes an outer diameter angle with direction of the centre axis, wherein said angle is in range of -10 ⁰ - +60 °.

An advantage is that an increased rotor pumping perfor10 mance may be provided, and blockage of the through-hole may be prevented.

In one embodiment, an innermost wall of the through-hole makes an inner diameter angle with direction of the centre 15 axis, wherein said angle is in range of -10 ⁰ - +60 °.

In one embodiment, at least one side wall of the throughhole makes a side wall angle with direction of the centre axis, wherein said angle is in range of -20 ° - +60 °.

In one embodiment, total area of the through-holes in re30 lation to the area of the cover dise is in range of 2 % 40 %, such as 20 % - 30 %. ,

An advantage is that an increased rotor pumping performance may be provided.

In one embodiment, area of the through-hole in relation to the cross-sectional area of the corresponding slurry slot is in range of 2 % - 40 %, such as 20 % - 30 %.

An advantage is that an enhanced rotor pumping performance may be provided.

In one embodiment, the upper surface of the cover dise comprises at least one top blade, arranged at least mainly 10 radially.

An advantage is that downwards flow of slurry through the through-holes may be increased.

In one embodiment, the length of the top blade is selected in range from 0.5 x the length of the corresponding through-hole in radial direction on the upper surface of the cover dise to a length equal to the radius of the upper surface.

An advantage is that an enhanced rotor pumping performance may be provided, and back flow through the through-hole may be prevented.

In one embodiment, the height of the top blade in relation to the height of the rotor measured from the bottom thereof to the underside of the cover dise is selected in range of 1 % - 50 %.

In one embodiment, the upper surface of the cover dise is 35 provided with an outer ring that has a height extending away from said upper surface.

An advantage is that slurry flow directed in the throughholes may be enhanced, and back flow through the throughhole may be prevented.

In one embodiment, the bottom surface of the air channel is incüned in relation to the plane of the cover dise in an inclination angle selected in range of 0 ° - 60 °, such as 5 ° - 30 °.

An advantage is that blockages of the air channel may be prevented.

In one embodiment, the length of the air channel in rela15 tion to the diameter (D) of the cover dise is selected in range of 10 % - 30 %, such as 20 %.

An advantage is that blockages of the air channel may be prevented. ·

In one embodiment, the shape of the air slot has a curved shape without any points of discontinuity.

An advantage is that blockages of the air slots and chan25 nels by slurry may be reduced.

In one embodiment, the center air void whereto the air channels are in fluid communication has designed and dimensioned such that the cross sectional area of ail the 30 air channels is at least substantially equal with the cross sectional area of an inlet receiving air in the rotor .

An advantage is that a fluent flow of air into the air 35 slots may be achieved.

In one embodiment, the shape of the slurry slot has an optimized shape so that its cross-sectional shape is at least substantially triangular in smaller rotors, and at least substantially rectangular in larger rotors.

An advantage is that an advantageous flow pattern in the slurry slot may be achieved.

BRIEF DESCRIPTION OF FIGURES

Some 'embodiments illustrating the présent disclosure are described in more detail in the attached drawings, in which

Figure 1 is a schematic top view of a rotor,

Figure 2 is a schematic side view of the rotor shown in Figure 1 in partial cross-section,

Figure 3 is a schematic top view of another rotor,

Figure 4 is a schematic side view of a detail of the rotor shown in Figure 3 in partial cross-section,

Figure 5 is a schematic side view of a detail of a rotor in partial cross-section, and

Figure 5 is a schematic top view of a through-hole.

In the figures, some embodiments are shown simplified for the sake of clarity. Similar parts are marked with the same reference numbers in the figures.

DETAILED DESCRIPTION

Figure 1 is a schematic top view of a rotor, and Figure 2 is a schematic side view of the rotor shown in Figure 1 in partial cross-section along a line A-A shown in Figure 1.

The rotor 100 is a rotor of a flotation machine, particularly used for dispersing air to a slurry. The rotor 100 can be arranged in e.g. a flotation cell. According to an aspect, the flotation cell may be used for e.g. recovering valuable ingrédients from slurry, such as slurry that contains minerais. According to another aspect, the flotation cell may be used in oil industry.

The rotor 100 can be arranged in e.g. a reactor tank wherein it is attached to a rotor shaft (not shown) that rotâtes the rotor around a centre axis X. When rotating, the rotor 100 sets the slurry fed into the flotation cell in motion and disperses air into the slurry, whereupon air bubbles are dispersed in the slurry. Air bubbles flow upwards and enter the surface of the slurry. In one embodiment, said air bubbles are participating in forming a froth bed on the surface of the slurry. However, in another embodiment there is no froth bed on the surface of the slurry.

The rotor 100 comprises a cover dise 1, the basic shape of which is preferably round.

Plurality of air slots 2 are arranged to protrude away from the cover dise 1. In the embodiment shown in Figures, there are six air slots in the rotor. It is to be noted, however, that the number of air slots may be less than six or more than six, such as two (2) to fifteen (15), preferably four (4) to seven (7).

The air slots 2 define an interior space 3 in the interior of the rotor.

An air channel 4 is connected to the air slot 2 for supplying air therein. In one embodiment, another end of the air channel 4 is connectai to a center air void 11 for supplying àir from said void to the air slot 2.

The rotor 100 comprises siurry slots 5 arranged between 5 and an alternating way with the air slots 2 around the interior space 3. The siurry slots 5 are in fluid communication with the interior space 3 so that siurry may flow from said interior space to said siurry slots 5.

The rotor 100 further comprises radially extending blades 6 that are arranged for separating the air slot 2 from adjacent siurry slots 5. The number of blades dépends on the number of air slots 2 and siurry slots 5. In the embodiment shown in Figures, the number of blades is twelve.

In one embodiment, the cross-sectional shape of the siurry slot 5 is at least substantially triangular. This embodiment is especially preferably in smaller rotors. In one embodiment, the smaller rotors means rotors having diam20 eter smaller than 1750 mm, even so small than 70 mm to 300 mm.

In one embodiment, the cross-sectional shape of the siurry slot 5 is at least substantially rectangular. This embodi25 ment is especially preferably in larger rotors. In one embodiment, the larger rotors means rotors having diameter 1750 mm or more, such as 2200 mm or even more, up to 4000 mm or 5000 mm.

The cover dise 1 comprises at least one through-hole 7 extending from an upper surface 8 of the cover dise to at least one of the siurry slots 5. In one embodiment, such as shown in Figures, ail the siurry slots 5 hâve a through-hole 7 of its own.

In one embodiment, some portion of the slurry slots 5 has the through-hole 7, whereas another portion of the slurry slots 5 is devoid of the through-holes 7. For instance, half of the slurry slots 5 has the through-hole 7, whereas 5 another half does not hâve the through-hole.

In one embodiment, such as shown in Figure 3, the outer circumference of upper surface 8 of the cover dise is provided with an outer ring 10 having a height extending away 10 from said upper surface. The outer ring 10 frames and surrounds the upper surface 8. The outer ring 10 may hâve a constant or varying height. The outer ring may surround the upper surface in a continuons way, or it may be discontinuons comprising at least one section where the outer 15 ring is missing, i.e. the height thereof is minimized to zéro.

The shape of the through-hole 7 is selected based on needs of the current application.

In one embodiment, the basic shape of the through-hole 7 is polygon, such as triangle, quadrangle, or trapézoïdal. Two adjacent corners of the polygon may be connected by a straight line or a curving line.

In one embodiment, the basic shape of the through-hole 7 is roundish, such as round, oval, or oviform.

In one embodiment, the basic shape of the through-hole 7 30 is a combination of polygon and roundish shapes.

In one embodiment, the cross-sectional area and shape of the through-hole 7 are constant or unchanging in ail its length from the upper surface 8 to the slurry slot 5. In 35 other embodiments, the cross-sectional area may vary. For example, the cross-sectional area may decrease from the

upper surface 8 towards the slurry slot 5, or vice versa. In one embodiment, the cross-sectional area increases from the upper surface 8 towards the slurry slot 5, thus a suction effect may be created in the through-hole 7.

In one embodiment, the cross-section of the through-hole 7 ' at the upper surface 8 may hâve a first shape, and a second shape at the slurry slot 5, the first and the second shapes being different.

Figure 6 is a schematic top view of a through-hole. In embodiments where the through-hole 7 is has a shape of polygon, the through-hole 7 may comprise at least one side edge 13 on the upper surface 8 of the cover dise that 15 makes a hole angle HA with radial direction RD of the rotor. In one embodiment, said hole angle HA is in range of -10 ⁰ - +45 °. Positive values of the hole angle mean that the through-hole 7 is converging towards the centre axis X, whereas négative values means the through-hole is con20 verging towards the outer circumference of the rotor.

In one embodiment, ail the through-holes 7 hâve same shape and size. In another embodiment, there are at least two different shapes and/or sizes in the through-holes.

In one embodiment, such as shown in Figures, there is one through-hole 7 per one slurry slot 5. In another embodiment, there is two or even more through-holes connected to one slurry slot 5.

In one embodiment, the total area of the through-holes 7 in relation to the area of the cover dise 1 is in range of 2 % - 40 %. In one embodiment, said relation is in range of 20 % - 30 %.

In one embodiment, the area of the through-hole 7 in relation to the cross-sectional area of the corresponding slurry slot 5 is in range of 2 % - 40 %. In one embodiment, said relation is in range of 20 % - 30 %.

'

In one embodiment, such as shown in Figures, the throughhole 7 is aligned askew in relation to the upper surface 8 or the centre axis X. Figure 4 is a schematic crosssectional view of the embodiment shown in Figure 3 along 10 line A-A. The through-hole 7 comprises an outmost wall 14 that makes an outer diameter angle ODA and an innermost wall 15 that makes an inner diameter angle IDA with direction of the centre axis. In one embodiment, said angles are selected in range of -10 ° - +60 ⁰ . Positive values 15 mean that the respective wall 14, 15 is directed outwards when seeing from the upper surface 8, i.e. in direction of slurry flow FS through said through-hole. Négative values mean that the respective wall 14, 15 is directed inwards when seeing from the upper surface 8.

Figure 5 is a schematic side view of a detail of the rotor shown in Figure 3 along line B-B. In one embodiment, at least one of a leading side wall 16a and a trailing side wall 16b of the through-hole makes a side wall angle SWA 25 with direction of the centre axis so that said angle is in range of -20 ° - +60 °. In one embodiment, said angle is in range of -10 ° - +60 °. In one embodiment,. said angle is in range of 0 ⁰ - +30 ⁰ .

The side wall angle SWA of the leading side wall 16a may be same as or differ from the SWA of the trailing side wall 16b.

Positive values of the side wall angle SWA mean that when 35 the rotor is rotating in its rotating direction R, an intersection of the side wall 16a, 16b and the upper surface précédés an intersection of said side wall and the underside of the cover dise 1.

In one embodiment, the leading side wall 16a and the trailing side wall 16b are parallel with the centre axis X, i.e. the side wall angle SWA is 0 °. This embodiment is especially advantageous if the rotor 100 is intended to rotate in both directions. This kind of bidirectional function of the rotor is advantageous in certain gas dispersion arrangements. However, it is to be noted that this kind of rotor, as well as any rotor described in the current disclosure, may also be used in unidirectional way. This means that the rotor is rotated just one direction in the gas dispersion arrangement.

Alignment of the through-holes 7 by choosing the outer diameter angle ODA, the inner diameter angle IDA, and the side wall angle SWA makes it is possible to optimize the slurry flow in the slurry slot and thereby create more effective rotors for the field of gas dispersion arrangements .

In one embodiment, the upper surface 8 of the cover dise is at least substantially even. However, in another embodiments, the upper surface 8 comprises three dimensional shapes, e.g. projections and/or recesses for e.g. guidance of flows on the upper surface.

In one embodiment, such as shown in Figures, the upper surface 8 comprises top blades 9. The top blades may be arranged at least mainly radially. In one embodiment, such as shown in Figures, each of the top blades 9 is radially arranged in relation to the cover dise 1. It is to be noted, however, that in some embodiments the direction of the blade(s) may diverge from the radial direction.

In one embodiment, there is at least one top blade 9 between each pair of through-holes 7. In the embodiment, such as shown in Figures, there is one top blade 9 between each pair of through-holes 7. Thus, the number of the top 5 blades 9 is equal with the number of the through-holes 7.

In one embodiment, the number of the top blades 9 is less than the number of the through-holes 7. In another embodiment, the number of the top blades 9 is greater than the 10 number of the through-holes 7.

In one embodiment, the length of the top blade 9 is selected in range from 0.5 x the length of the corresponding through-hole 7 in radial direction on the upper surface 8 15 of the cover dise to a length equal to the radius of the upper surface.

In one embodiment, the height of the top blade in relation to the height H of the rotor measured from the bottom 20 thereof to the underside of the cover dise 1 is selected in range of 1 % - 50 %. In one embodiment, said range is 5 % - 30 %. The height of the top blade 9 may be constant over ail the length of the blade; alternatively, there may be variations- in its height. In one embodiment, the height 25 of the top blade 9 has its maximum near the centre axis X and from which it lowers towards the outer circumference of the rotor.

The shape of the top blade 9 is selected based on needs of 30 the current application. By suitable shaping of the top blades, it is possible to control power consumption of the rotor as well as flow patterns of slurry. In one embodiment, such as shown in Figures, ail the top blades 9 has same dimensions and shapes; however, this is not always 35 necessary.

In one embodiment, the top blade 9 is straight.

In one embodiment, the top blade 9 is curved or comprises at least one curve.

In one embodiment, the shape of the top blade 9 is a combination of two or more straight sections and/or straight and curved sections.

In one embodiment, the top blade 9 is arranged perpendicularly in relation to the upper surface 8.

In one embodiment, the top blade 9 is arranged in relation to the upper surface 8 to an angle diverging from perpen15 dicular angle, i.e. the top blade 9 may be inclined in relation to the upper surface, either in direction of rotation of the rotor or to another direction.

In one embodiment, such as shown in Figures, the top blade 20 9 extends to an outer edge of cover dise 1. However, this is not always necessary. '

As mentioned earlier in this disclosure, the air channels 4 are connected to the air slot 2 for supplying air there25 in. In one embodiment, the bottom surface of the air channel 4 is inclined in relation to the plane P of the cover dise in an inclination angle IA that selected in range of 0 ⁰ - 60 °, preferably 5 ⁰ - 30 °. In one embodiment, the top surface of the air channel 4 is parallel with the bot30 tom surface. In another embodiment, the top surface of the air channel 4 is not parallel with the bottom surface, i.e. it is deviating from the inclination angle IA. The inclination angle IA ensures that if some slurry gets in the air channel, it also cornes back out from there.

The length of the air channel 4 is preferably as short as possible in order to minimize its susceptibility to clogging by slurry. In one embodiment, the length of the air channel in relation to the diameter (D) of the cover dise is selected in range of 10 % - 30 %, preferably 20 %.

The shape of the air slot 2 has preferably a curved shape without any points of discontinuity.

In one embodiment, the center air void 11 whereto the air channels 4 are in fluid communication has designed and dimensioned such that the cross sectional area of ail the air channels 4 is at least substantially equal with the cross sectional area of an inlet receiving air in the rotor 100.

In one embodiment, air is supplied to the center air void 11 by a hollow rotor shaft (not shown).

The invention is not limited solely to the embodiments described above, but instead many variations are possible within the scope of the inventive concept defined by the claims below. Within the scope of the inventive concept' the attributes of different embodiments and applications can be used in conjunction with or replace the attributes of another embodiment or application.

The drawings and the related description are only intended to illustrate the idea of the invention. The invention may vary in detail within the scope of the inventive idea defined in the following claims.

REFERENCE SYMBOLS cover dise air slot interior space air channel slurry slot blade through-hole upper surface top blade outer ring center air void side edge outmost wall innermost wall

16a, b side wall

100 rotor

D diameter of cover dise

FA air flow

FS slurry flow

H height

HA hole angle

IA inclination angle

IDA inner diameter angle

ODA outer diameter angle

P plane of cover dise

R direction of rotation

RD radial direction

SWA side wall angle

X centre axis

Claims

1. A rotor (100) of a gas dispersion arrangement, comprising

2. The rotor as claimed in claim 1, wherein

- the through-hole (7) has a shape of a polygon.

3. The rotor as claimed in claim 2, wherein

25 - the through-hole (7) comprises at least one side edge (13) on the upper surface (8) that makes a hole angle (HA) with radial direction (RD) of the rotor, wherein said angle is in range of -10° - +45°.

30

4. The rotor as claimed in claim 1, wherein

- the through-hole (7) has a roundish shape.

5. The rotor as claimed in any of the preceding claims, wherein

35 - an outmost wall (14) of the through-hole (7) makes an outer diameter angle (ODA) with direction of the centre

axis, wherein said outer diameter angle is in range of 10° - +60°.

5 - a cover dise (1),

- air slots (2) arranged to protrude away from the cover dise (1), the air slots (2) defining an interior space (3) in an interior of the rotor,

- an air channel (4) connected to the air slots (2) for 10 supplying air to be dispensed in slurry,

- slurry slots (5) arranged between and in an alternating way with the air slots (2) around the interior space (3),

- the slurry slots (5) being in fluid communication with the interior space (3),

15 - radially extending blades (6) arranged for separating the air slots (2) from adjacent slurry slots (5), wherein - the cover dise (1) comprises at least one through-hole (7) extending from an upper surface (8) of the cover dise (1) to at least one of the slurry slots (5).

6. The rotor as claimed in any of the preceding daims, 5 wherein

- an innermost wall (15) of the through-hole (7) makes an inner diameter angle (IDA) with direction of the centre axis, wherein said inner diameter angle is in range of 10° - +60°.

7. The rotor as claimed in any of the preceding daims, wherein .

- at least one side wall (16a, 16b) of the through-hole (7) makes a side wall angle (SWA) with direction of the 15 centre axis, wherein said side wall angle is in range of 20° - +60°.

8. The rotor as claimed in any of the preceding daims, wherein

20 - total area of the through-hole (7) in relation to an area of the cover dise is in range of 2% - 40%.

9. The rotor as claimed in any of the preceding daims, wherein

25 - area of the through-hole (7) in relation to a crosssectional area of a corresponding slurry slot (8) is in range of 2% - 40%.

10. The rotor as claimed in any of the preceding daims, 30 wherein

- the upper surface (8) of the cover dise (1) comprises at least one top blade (9), arranged at least mainly radially.

35

11. The rotor as claimed in daim 10, wherein

- a length of the top blade (9) is selected in range from 0.5 x the length of a corresponding through-hole (7) in radial direction on the upper surface (8) of the cover dise (1) to a length equal to the radius of the upper sur5 face (8 ) .

12. The rotor as claimed in claim 10 or 11, wherein

- a height of the top blade (9) in relation to a height (H) of the rotor measured from a bottom thereof to an un10 derside of the cover dise (1) is selected in range of 1% 50%.

13. The rotor as claimed in any of the preceding claims, wherein

15 - the upper surface (8) of the cover dise (1) is provided with an outer ring (10) that has a height extending away from said upper surface (8).

14. The rotor as claimed in any of the preceding claims, 20 wherein

- a bottom surface of the air channel (4) is inclined in relation to a plane (P) of the cover dise (1) in an inclination angle (IA) selected in range of 0° - 60°.

25

15. The rotor as claimed in any of the preceding claims, wherein

- a length of the air channel (4) in relation to a diameter (D) of the cover dise (1) is selected in range of 10% - 30%. 30 .

16. The rotor as claimed in any of the preceding claims, wherein

- the air slot (2) has a curved shape without any points of discontinuity.

17. The rotor as claimed in any of the preceding daims, wherein

- the air channel (4) is connected to a center air void (11) for supplying air to said air channel (4), wherein 5 the center air void (11) is designed and dimensioned such that a cross-sectional area of the air channel (4) is at least substantially equal with a cross-sectional area of an inlet receiving air in the rotor (100).

10 18. The rotor as claimed in any of the preceding daims, wherein

- a cross-sectional shape of each of the slurryslots (5) is at least substantially triangular in smaller rotors, and at least substantially rectangular in larger rotors.