Impeller, a diffuser and an arrangement using such impeller and diffuser in a flotation tank

Patent metadata

Field	Value
Publication number	US-2022347635-A1
Application number	US-202117243690-A
Country	US
Kind code	A1
Filing date	Apr 29, 2021
Priority date	Apr 29, 2021
Publication date	Nov 3, 2022
Grant date	—

Abstract

An impeller and a diffusor is provided which are configured to be used in a flotation tank to enhance mixing of gas and slurry. The impeller comprises two opposing inlet ends and the diffusor comprises two opposing inlet mouths. The impeller is configured, when arranged inside the diffusor, to pump a bi-directional axial flow of slurry into the diffusor. Further, an arrangement using such diffusor and impeller for the use in a flotation tank to enhance mixing of gas and slurry is provided.

First claim

We claim:

1 . An impeller for mixing a gas and a slurry in a flotation tank, the impeller comprising:
a first section having a first inlet end and a first outlet end interconnected by a first envelope surface; a second section having a second inlet end and a second outlet end interconnected by a second envelope surface; and a middle section having a first end and a second end; the first and second ends being interconnected by a side wall extending along a rotation axis of the impeller; wherein the first outlet end of the first section is connected to the first end of the middle section, and the second outlet end of the second section is connected to the second end of the middle section; and wherein the side wall of the middle section comprises at least one gas outlet configured to communicate with a gas supply.

2 . The impeller according to claim 1 , wherein the first and/or the second envelope surface has a concave shape as seen in view of the rotation axis of the impeller.

3 . The impeller according to claim 1 , wherein the first envelope surface comprises a plurality of vanes having an extension in a direction between the first inlet end and the first outlet end; and/or
the second envelope surface comprises a plurality of vanes having an extension in a direction between the second inlet end and the second outlet end.

4 . The impeller according to claim 3 , wherein the vanes of the first envelope surface have an outer edge facing away from the first envelope surface, said outer edge having a concave shape as seen in view of the rotation axis of the impeller; and/or
wherein the vanes of the second envelope surface have an outer edge facing away from the second envelope surface, said outer edge having a concave shape as seen in view of the rotation axis of the impeller.

5 . The impeller according to claim 3 , wherein the vanes of the second envelope surface have an inner edge facing the rotation axis of the impeller, and an outer edge facing away from the rotation axis of the impeller, wherein the inner and outer edges merges in a tip, wherein said tip is radially displaced in view of the rotation axis of the impeller.

6 . The impeller according to claim 3 , wherein a vane in the first section and a vane in the second section form a pair of vanes, and wherein radially outer edges of the vanes in each pair together with the side wall of the middle section have an extension substantially in parallel with the rotation axis of the impeller.

7 . The impeller according to claim 1 , wherein the middle section further comprises a circumferentially extending groove communicating with the at least one gas outlet.

8 . The impeller according to claim 7 , wherein the groove comprises a plurality of radially extending fins; and/or wherein the plurality of fins have an extension in the radial direction of the groove which is smaller than a radial depth of the groove, and wherein the plurality of fins have an outer edge portion which is aligned with the side wall of the middle section.

9 . A diffusor for mixing a gas and a slurry in a flotation tank, the diffusor comprising:
a first annular section; a second annular section; and a middle section comprising a plurality diffusor blades extending along a longitudinal center line of the diffusor, and wherein the first annular section and the second annular section are connected on opposite sides of the middle section as seen along the longitudinal center line of the diffusor; wherein the first annular section comprises a funnel shaped inlet end forming a first inlet mouth of the diffusor; and the second annular section comprises a funnel shaped inlet end forming a second inlet mouth of the diffusor.

10 . The diffusor according to claim 9 , wherein the first annular section further comprises a funnel shaped outlet end, and wherein a narrow end of the funnel shaped inlet end merges with a narrow end of the funnel shaped outlet end, and the middle section interconnects with a wide end of the funnel shaped outlet end; and
the second annular section further comprises a funnel shaped outlet end, and wherein a narrow end of the funnel shaped inlet end merges with a narrow end of the funnel shaped outlet end, and the middle section interconnects with a wide end of the funnel shaped outlet end.

11 . The diffusor according to claim 9 , wherein the funnel shaped inlet and outlet ends of the first and second annular sections each have a convex envelope surface as seen in view of the longitudinal center line of the diffusor.

12 . The diffusor according to claim 9 , wherein the first and second inlet mouths each have a radius being smaller than an inner most radius of the plurality of diffusor blades.

13 . The diffusor according to claim 9 , wherein the second annular section and the middle section each has a length along the longitudinal center line of the diffusor, and wherein the length of the second annular section exceeds or corresponds to the length of the middle section.

14 . The diffusor according to claim 9 , wherein the first annular section and the middle section each has a length along the longitudinal center line of the diffusor, and wherein the length of the first annular section is smaller than the length of the middle section.

15 . The diffusor according to claim 9 , wherein the first annular section and the second annular section each has a length along the longitudinal center line of the diffusor, and wherein the length of the first annular section is smaller than the length of the second annular section.

16 . The diffusor according to claims 9 , wherein the radius of the second inlet mouth of the diffusor is smaller than the radius of the first inlet mouth of the diffusor.

17 . Arrangement for the use in a flotation tank to enhance mixing of gas and slurry, the apparatus comprising an impeller according to claim 1 and a diffusor according to claim 9 , wherein the impeller is configured to be rotatably and coaxially received inside the diffusor.

18 . The arrangement according to claim 17 , wherein the outer edge of the vanes on the first section of the impeller have a shape being substantially complementary to a portion of the funnel shaped outlet end of the first annular section of the diffusor; and/or wherein
the outer edge of the vanes on the second section of the impeller have a shape being substantially complementary to a portion of the funnel shaped outlet end of the second annular section of the diffusor.

19 . The arrangement according to claim 17 , wherein a radially extending gap is formed between the side wall of the middle section of the impeller and the plurality of diffusor blades of the diffusor.

20 . Use of an arrangement according to claim 17 in a flotation tank to enhance mixing of gas and slurry.

Assignees

• Metso Outotec Finland Oy

Inventors

• Humphris James
• Nilsson Björn
• Howie Max H

Classifications

• B01F27/8111

  the stirrers co-operating with stationary guiding elements, e.g. surrounding stators or intermeshing stators (B01F27/812 takes precedence) · CPC title

• B01F23/2331

  characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements · CPC title

• B01F23/23311

  through a hollow stirrer axis · CPC title

• B01F23/23314

  through a hollow stirrer element · CPC title

• B01F23/23342

  the stirrer being of the centrifugal type, e.g. with a surrounding stator · CPC title