NEW FILTER, FILTER UNIT, TREATMENT APPARATUS, METHOD AND USE

Abstract

This invention relates to a filter which is especially for filtering microfibres which can, for example, originate from the washing of textiles. The filter is rotatable around an axis of rotation. The filter provides good filtering efficiency and improved resistance to blocking.

Claims

1. A filter suitable for a filter unit, the filter being rotatable around an axis of rotation, the filter comprising: a) a first end, a second end and one or more side walls connecting the first end of the filter and the second end of the filter, wherein the first end, second end and one or more side walls of the filter define a filter chamber; b) an inlet located in the first end of the filter, wherein said inlet is configured to allow a feed to enter the filter chamber; c) a filter medium having a first surface, wherein the first surface is the surface through which the feed enters the filter medium and is filtered; and wherein at least requirements i) and iv) are met: i) at least a portion of said first surface is oriented such that when the filter is operating and rotating about the axis of rotation any solid material accumulating on said first surface is urged away from said first surface; ii) at least one of the side walls of the filter has perforations provided that no more than 50% of the surface area of said at least one side wall is occupied by said perforations; iii) the filter additionally comprises a flow path which is defined and constrained by one or more surfaces within the filter chamber, said flow path having at least a portion which is not coincident with the axis of rotation of the filter during operation nor is it radial with regard to the axis of rotation during operation; iv) the filter comprises a plurality of filter media, at least some of which are stacked in layers.

2. A filter according to claim 1 wherein at least a portion of said first surface is oriented in a plane which is no more than 50 degrees from a radial plane when the filter is in operation.

3. A filter according to claim 2 wherein at least a portion of said first surface is oriented in a plane which is no more than 20 degrees from a radial plane when the filter is in operation.

4. A filter according to claim 2 or 3 wherein the portion is at least 50% of said surface area of said first surface.

5. A filter according to any one of claims 2 to 4 wherein during operation the feed flows over said first surface in a direction flowing away from the axis of rotation and towards the one or more side walls.

6. A filter according to any one of the preceding claims wherein said first surface is planar.

7. A filter according to any one of the preceding claims wherein the filter medium is planar.

8. A filter according to any one of the preceding claims wherein requirement ii) is additionally met.

9. A filter according to claim 8 wherein at least one of the side walls of the filter has perforations provided that no more than 10% of the surface area of said at least one side wall is occupied by said perforations.

10. A filter according to claim 9 having two or more side walls, wherein two or more of the side walls of the filter have perforations provided that in totality no more than 10% of the total surface area of all of the side walls are occupied by said perforations.

11. A filter according to any one of claims 8 to 10 wherein no side wall present has perforations.

12. A filter according to any one of claims 1 to 11 wherein the one or more side walls are attached to the first end; and the second end is detachable from the one or more side walls.

13. A filter according to any one of the preceding claims comprising one or more regions where during operation of said filter, solid material present in the feed can accumulate on an interior surface of the one or more side walls.

14. A filter according to any one of the preceding claims wherein requirement iii) is additionally met.

15. A filter according to claim 14 wherein at least a portion of the flow path is defined and constrained by one or more surfaces in the form of channels, tubes, pipes and the like.

16. A filter according to claim 14 or 15 wherein the flow path terminates with a flow path outlet in the filter.

17. A filter according to claim 16 wherein the flow path outlet in the filter is located in the second end of the filter.

18. A filter according to any one of claims 14 to 17 wherein the flow path is not defined and constrained by one or more surfaces which include the interior surface of any of the side walls.

19. A filter according to any one of claims 14 to 18 wherein the flow path is separated from the one or more side walls and from the axis of rotation of the filter.

20. A filter according to any one of claims 14 to 19 wherein the flow path is configured such that when in operation filtered feed flowing along the flow path will not disturb solid material which has accumulated on the interior surface of the one or more side walls.

21. A filter according to any one of claims 14 to 20 which comprises a plurality of filter media, and a plurality of flow paths, each flow path being associated with a filter media.

22. A filter according to claim 21 wherein at least a portion of the plurality of flow paths is common and ends in a shared flow path outlet in the filter.

23. A filter according to any one of the preceding claims wherein the filter media in the stacked layers are all of the same shape, preferably wherein the shapes are selected from those having a planar, corrugated, concave and convex shape.

24. A filter according to claim 23 wherein filter media in the stacked layers all have a planar shape.

25. A filter according to any one of the preceding claims comprising at least four filter media which are stacked in layers.

26. A filter according to any one of the preceding claims wherein the filter medium comprises perforations, optionally wherein said perforations have an average largest dimension of no more than 1 mm.

27. A filter according to any one of the preceding claims having a filter medium located in the first and/or second end of the filter, or having a further filter medium located in the first and/or second end of the filter.

28. A filter unit comprising a filter according to any one of the preceding claims.

29. A filter unit according to claim 28 wherein the filter unit comprises a filter unit housing, a drive means for rotating the filter around an axis of rotation, a housing inlet which during use allows feed to enter the filter unit and a housing outlet which during use allows feed to exit the filter unit.

30. A filter unit according to claim 28 or 29 which is water-tight.

31. A filter unit according to claim 28 which has one or more openings in the filter unit housing other than the housing inlet and housing outlet.

32. A treatment apparatus, for treating a substrate with a treatment formulation comprising a liquid, the treatment apparatus comprising a drum for rotating the substrate and the treatment formulation, a drive means for rotating the drum and a filter according to any one of claims 1 to 27 or a filter unit according to any one of claims 28 to 31.

33. A treatment apparatus according to claim 32 which is a washing machine, a textile treatment machine or a tanning machine.

34. A method of filtering a feed comprising solid material in the form of particles and a liquid, the method comprising using a filter according to any one of claims 1 to 27 or a filter unit according to any one of claims 28 to 31 and rotating the filter whilst the feed flows through the filter.

35. A method of filtering a feed according to claim 34 wherein the particles are or comprise fibres.

36. A method of filtering a feed according to claim 35 wherein at least some of said fibres have a longest linear dimension of from 1 μm to 1 mm.

37. A method of filtering a feed according to claim 35 or 36 wherein the fibres are derived from a substrate which has been treated in a treatment formulation comprising liquid.

38. Use of a filter according to any one of claims 1 to 27 or a filter unit according to any one of claims 28 to 31 for filtering a feed.

Description

FIGURES

[0236] The invention is further illustrated with reference to the following figures in which:

[0237] FIG. 1 shows a schematic representation of the orientation of the first surface of the filter medium in part of a cross-section of a filter where the first surface of the filter medium is oriented in a plane at an angle α to the radial plane.

[0238] FIG. 2 shows a schematic representation of an alternative orientation of the first surface of the filter medium in part of a cross-section of a filter where the first surface of the filter medium is oriented in a plane which is parallel to the radial plane.

[0239] FIG. 3 shows a schematic representation of an alternative orientation of the first surface of the filter medium in part of a cross-section of a filter where the first surface of the filter medium is parallel to the axis of rotation and faces the side wall of the filter.

[0240] FIG. 4 shows a 3D cross-section view of a filter according to the present invention.

[0241] FIG. 5 shows an exploded isometric view on an alternative filter with many of the layers of the filter separated and partially disassembled.

[0242] FIG. 6 is an illustration of a cross-section of an alternative filter according to the present invention.

DETAILED DESCRIPTION

[0243] The present invention will now be further elaborated by reference to the figures which are non-limiting.

[0244] FIG. 1 shows a schematic representation of the orientation of the first surface of the filter medium in part of a cross-section of a filter where the first surface is oriented in a plane at an angle α to the radial plane.

[0245] FIG. 1 shows the filter medium (1), the first surface (2) of the filter medium and radial plane labelled (A) which points away from the axis of rotation (C). The radial plane (A) is the plane which is perpendicular to the axis of rotation (C) when the filter is in operation and is being rotated around the axis of rotation. The first end (5) and the second end (6) are shown in part. The first surface (2) of the filter medium is oriented in a plane which has an angle α with respect to the radial plane when the filter is in operation. The arrow labelled (B) shows the direction of the flow of the feed as it passes through the filter medium (1). The side wall (3) has an interior surface (4) on which solid material will accumulate during the operation of the filter. When the filter is operating and rotating about the axis of rotation (C) any solid material accumulating on the first surface (2) is centripetally urged away from the first surface (2) of the filter medium. Thus, a filter as shown in FIG. 1) will tend to self-clean the first surface (2) and the solid material will instead tend to accumulate on the interior surface (4) of the side wall (3).

[0246] FIG. 2 shows a schematic representation of the orientation of the first surface of the filter medium in part of a cross-section of a filter where the first surface of the filter medium is oriented in a plane parallel to the radial plane.

[0247] FIG. 2 shows the filter medium (1), the first surface (2) and radial plane labelled (A) which points away from the axis of rotation (C). The first end (5) and the second end (6) are shown in part. The first surface (2) of the filter medium is oriented in a plane which is parallel to the radial plane (A) when the filter is in operation. The arrow labelled (B) shows the direction of the flow of the feed as it passes through the filter medium (1). The side wall (3) has an interior surface (4) on which solid material will accumulate during the operation of the filter. When the filter is operating and rotating about the axis of rotation (C) any solid material accumulating on said first surface (2) is centripetally urged along and ultimately away from the first surface (2) of the filter medium. Thus, a filter as shown in FIG. 2) will tend to self-clean the first surface (2) and the solid material will instead tend to accumulate on the interior surface (4) of the side wall (3). Preferably, the flow of the feed (not shown) over the first surface (2) of the filter medium follows the arrow labelled (A) and is parallel to a radial plane in a direction away from the axis of rotation.

[0248] FIG. 3 shows a schematic representation of the orientation of the first surface of the filter medium in part of a cross-section of a filter where the first surface faces the side wall of the filter.

[0249] FIG. 3 shows the filter medium (1) and the first surface (2). The first end (5) and the second end (6) are shown in part. The filter medium has a first surface (2) which is oriented with an angle β with respect to the arrow (D) which is parallel to the axis of rotation labelled as arrow (C). The first surface (2) of the filter medium is oriented such that it faces at the side wall (3). The side wall (3) has an interior surface (4) on which solid material will accumulate during operation of the filter. When the filter is operating and rotating about the axis of rotation (C) solid material accumulating on said first surface (2) is centripetally urged away from the first surface (2) of the filter medium. Thus, a filter as shown in FIG. 3) will tend to self-clean the first surface (2) and the solid material will instead tend to accumulate on the interior surface (4) of the side walls (3). The arrow labelled (B) shows the direction of the feed as it passes through the filter medium (1). The arrow labelled (A) shows a radial plane as it extends away from the axis of rotation (C).

[0250] FIG. 4 shows a 3D cross-section view of a filter (100) according to the present invention The filter is cylindrical in shape.

[0251] The filter (100) has a first end (101), a second end (102) and a side wall (103). The first end (101) and second end (102) are substantially circular and the side wall (103) is cylindrical. The cylindrical side wall (103) has no perforations. The axis of rotation during the operation of the filter is shown by the line (C). The filter (100) has four equally spaced filter media (104) located in the first end (101), one of which is shown in full and two are shown in part, and four filter media (104′) located in the second end (102). The filter media (104, 104′) are located further away from the axis of rotation (C) and more towards the outmost circumference of the first end (101) or second end (102). The filter media (104, 104′) serve as outlets from the filter (100). The filter media (104, 104′) are planar and have a first surface (109, 109′) which is oriented in a plane parallel to a radial plane. The first end (101) has an inlet (105) located axially and through which a feed (shown by arrow F) is able to enter the filter chamber (106). The filter (100) has an impeller with four flat blades (107) projecting outwardly from the axis of rotation, two of which are shown. Rotation of the filter (100) causes the feed to travel from the filter chamber and out through the filter medium (104, 104′, shown by arrow B). In use solid material accumulates preferentially on the interior surface (108) of the side wall (103). Solid material which would otherwise have accumulated on the surface (109, 109′) of the filter medium (104, 104′) through which the feed passes is centripetally urged towards the interior surface (108) of the side wall (103) as the filter (100) is rotated during operation. The first end (102) is detachable from the side wall (103) and the second end (101) and when the filter (100) needs cleaning this detachability provides for easy access and cleaning out of the accumulated solid material.

[0252] FIG. 5 shows an exploded isometric view of an alternative filter (200) with many of the layers of the filter separated and partially disassembled. The filter is cylindrical in shape.

[0253] The filter has a first end (201), a second end (202) and a side wall (203). The first end (201) and second end (202) are substantially circular and the side wall (203) is cylindrical. The first end (201), second end (202) and side wall (203) form the filter chamber. The cylindrical side wall (203) has no perforations. The filter (200) comprises a plurality of filter media which are planar, which are located on filter supports which take the form of discs. The combination of filter media and supports are called a filter layer (204a, 204b1, 204b2 and 204c) and these filter layers (204a, 204b1, 204b2 and 204c) are stacked with their centres along the axis of rotation. The first surfaces of the filter media through which the feed passes are oriented in a plane which is parallel to a radial plane.

[0254] The filter (200) comprises substantially disc-shaped impeller layers (205a, 205b1, 205b2 and 205c), disc-shaped directing layers (206a, 206b and 206c) and a top layer (207) which terminates the layers nearest the first end (201). Each impeller layer comprises six blades. The filter layers (204a, 204b1, 204b2 and 204c), impeller layers (205a, 205b1, 205b2 and 205c), directing layers (206a, 206b and 206c) and top layer (207) are stacked in the filter (200). The first end (201) an inlet (208) located axially and through which the feed is able to enter the filter chamber. Each layer (207, 206a,b,c, 205a,b1,b2,c, and 204a,b1,b2,c) has an axial aperture (220) located along the axis of rotation (C) which permits feed entering the filter chamber to flow to the filter media within the filter (200). Each of the layers (207, 206a,b,c, 205a,b1,b2,c, and 204a,b1,b2,c) has a cut-out portion (209) towards the circumference of the disc which are aligned. These cut-out portions (209) provide regions around the interior surface (not shown) of the side wall (203) in which the solid material can accumulate without blocking the flow of the feed as it passes through the filter. Each layer (206a,b,c, 205a,b1,b2,c, and 204a,b1,b2,c), with the exception of the top layer (207), is provided with apertures (210a, 210b, 210c) which are located proximate to the side wall, around the circumference of each layer. These apertures are aligned when the layers are stacked to form a common portion of the flow path which permits feed having passed through the filter media to readily exit the filter (200) via twelve flow path outlets (211) in the second end (202), eight of which are shown in FIG. 5. Surfaces of the filter media through which feed enters the filter (200) are spaced permitting the flow of the liquid and the movement of accumulating solid material.

[0255] During the operation of the filter (200), solid material accumulates in the regions created by the cut-out portions (209) of the layers and on the interior surface of the side wall (203). Solid material which would otherwise have tended to accumulate on the first surface of the filter medium through which the feed passes is centripetally urged away from the first surface and radially outwards towards the side wall (203). In this way the filter (200) is “self-cleaning” during operation and rotation.

[0256] Openings (213) in the layers and the first and second end (201, 202) provide a means to align the layers and to lock the layers and filter components together using guide rods (not shown). A seal in the form of an O-ring (212) is provided in the second end (202) such that it is readily detachable from the first end (201) and side wall (203).

[0257] FIG. 6 is an illustration of a cross-section of an alternative filter according to the present invention. The filter is cylindrical in shape.

[0258] The filter has a filter medium (1) having a first surface (2) which surrounds the axis of rotation (C). The side wall (3) is cylindrical and has an internal surface (4) and no perforations. The side wall (3) is attached to a substantially circular first end (5) and a substantially circular second end (6). An inlet (7) in the first end (1) permits feed (shown by arrow F) to enter the filter during operation. When in use and the filter is rotated the small arrows show the direction of the flow of the feed. The first surface (2) faces the side wall (3). The first surface (2) is oriented so as to be parallel to the axis of rotation (C) and parallel to the side wall (3). The filter medium (1) also acts as the outlet for the filter.

[0259] In use the filter is rotated and feed enters the filter chamber (shown by arrow F). The feed passes through the filter medium (1). The filter medium (1) is oriented such that when the filter is operating and rotating about the axis of rotation (C) any solid material accumulating on the first surface (2) is urged away from the first surface (2). The solid material tends to accumulate on the interior surface (4) of the side wall (3) which have no perforations. In this way the filter is “self-cleaning” during operation and rotation.

[0260] General

[0261] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0262] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0263] The following are numbered clauses of the invention:

1. A filter suitable for a filter unit, the filter being rotatable around an axis of rotation, the filter comprising:

[0264] a) a first end, a second end and one or more side walls connecting the first end of the filter and the second end of the filter, wherein the first end, second end and one or more side walls of the filter define a filter chamber;

[0265] b) an inlet located in the first end of the filter, wherein said inlet is configured to allow a feed to enter the filter chamber;

[0266] c) a filter medium having a first surface, wherein the first surface is the surface through which the feed enters the filter medium and is filtered; and

wherein one or more of the following requirements are met:

[0267] i) at least a portion of said first surface is oriented such that when the filter is operating and rotating about the axis of rotation any solid material accumulating on said first surface is urged away from said first surface;

[0268] ii) at least one of the side walls of the filter has perforations provided that no more than 50% of the surface area of said at least one side wall is occupied by said perforations;

[0269] iii) the filter additionally comprises a flow path which is defined and constrained by one or more surfaces within the filter chamber, said flow path having at least a portion which is not coincident with the axis of rotation of the filter during operation nor is it radial with regard to the axis of rotation during operation;

[0270] iv) the filter comprises a plurality of filter media, at least some of which are stacked in layers.

2. A filter according to clause 1 wherein at least a portion of said first surface is oriented such that when the filter is operating and rotating about the axis of rotation any solid material accumulating on said first surface is urged away from the first surface.
3. A filter according to clause 1 or 2 wherein at least a portion of said first surface is oriented in a plane which is no more than 50 degrees from a radial plane when the filter is in operation.
4. A filter according to clause 3 wherein at least a portion of said first surface is oriented in a plane which is no more than 20 degrees from a radial plane when the filter is in operation.
5. A filter according to clause 3 or 4 wherein the portion is at least 50% of said surface area of said first surface.
6. A filter according to any one of clauses 3 to 5 wherein during operation the feed flows over said first surface in a direction flowing away from the axis of rotation and towards the one or more side walls.
7. A filter according to any one of the preceding clauses wherein said first surface is planar.
8. A filter according to any one of the preceding clauses wherein the filter medium is planar.
9. A filter according to any one of the preceding clauses wherein at least one of the side walls of the filter has perforations provided that no more than 50% of the surface area of said at least one side wall is occupied by said perforations.
10. A filter according to clause 9 wherein at least one of the side walls of the filter has perforations provided that no more than 10% of the surface area of said at least one side wall is occupied by said perforations.
11. A filter according to clause 10 having two or more side walls, wherein two or more of the side walls of the filter have perforations provided that in totality no more than 10% of the total surface area of all of the side walls are occupied by said perforations.
12. A filter according to any one of clauses 9 to 11 wherein no side wall present has perforations.
13. A filter according to any one of clauses 1 to 12 wherein the one or more side walls are attached to the first end; and the second end is detachable from the one or more side walls.
14. A filter according to any one of the preceding clauses comprising one or more regions where during operation of said filter, solid material present in the feed can accumulate on an interior surface of the one or more side walls.
15. A filter according to any one of the preceding clauses which additionally comprises a flow path which is defined and constrained by one or more surfaces within the filter chamber, said flow path having at least a portion which is not coincident with the axis of rotation of the filter during operation nor is it radial with regard to the axis of rotation during operation.
16. A filter according to clause 15 wherein at least a portion of the flow path is defined and constrained by one or more surfaces in the form of channels, tubes, pipes and the like.
17. A filter according to clause 15 or 16 wherein the flow path terminates with a flow path outlet in the filter.
18. A filter according to clause 17 wherein the flow path outlet in the filter is located in the second end of the filter.
19. A filter according to any one of clauses 15 to 18 wherein the flow path is not defined and constrained by one or more surfaces which include the interior surface of any of the side walls.
20. A filter according to any one of clauses 15 to 19 wherein the flow path is separated from the one or more side walls and from the axis of rotation of the filter.
21. A filter according to any one of clauses 15 to 20 wherein the flow path is configured such that when in operation filtered feed flowing along the flow path will not disturb solid material which has accumulated on the interior surface of the one or more side walls.
22. A filter according to any one of clauses 15 to 21 which comprises a plurality of filter media, and a plurality of flow paths, each flow path being associated with a filter media.
23. A filter according to clause 22 wherein at least a portion of the plurality of flow paths is common and ends in a shared flow path outlet in the filter.
24. A filter according to any one of the preceding clauses which comprises a plurality of filter media, at least some of which are stacked in layers.
25. A filter according to clause 24 wherein the filter media in the stacked layers are all of the same shape, preferably wherein the shapes are selected from those having a planar, corrugated, concave and convex shape.
26. A filter according to clause 25 wherein filter media in the stacked layers all have a planar shape.
27. A filter according to any one of clauses 24 to 26 comprising at least four filter media which are stacked in layers.
28. A filter according to any one of the preceding clauses wherein requirements i. and ii. are met.
29. A filter according to clause 28 wherein requirements i., ii. and iii. are met.
30. A filter according to clause 29 wherein requirements i., ii., iii., and iv. are met.
31. A filter according to any one of the preceding clauses wherein the filter medium comprises perforations, optionally wherein said perforations have an average largest dimension of no more than 1 mm.
32. A filter according to any one of the preceding clauses having a filter medium located in the first and/or second end of the filter, or having a further filter medium located in the first and/or second end of the filter.
33. A filter unit comprising a filter according to any one of the preceding clauses.
34. A filter unit according to clause 33 wherein the filter unit comprises a filter unit housing, a drive means for rotating the filter around an axis of rotation, a housing inlet which during use allows feed to enter the filter unit and a housing outlet which during use allows feed to exit the filter unit.
35. A filter unit according to clauses 33 or 34 which is water-tight.
36. A filter unit according to clause 34 which has one or more openings in the filter unit housing other than the housing inlet and housing outlet.
37. A treatment apparatus, for treating a substrate with a treatment formulation comprising a liquid, the treatment apparatus comprising a drum for rotating the substrate and the treatment formulation, a drive means for rotating the drum and a filter according to any one of clauses 1 to 32 or a filter unit according to any one of clauses 33 to 36.
38. A treatment apparatus according to clause 37 which is a washing machine, a textile treatment machine or a tanning machine.
39. A method of filtering a feed comprising solid material in the form of particles and a liquid, the method comprising using a filter according to any one of clauses 1 to 32 or a filter unit according to any one of clauses 33 to 36 and rotating the filter whilst the feed flows through the filter.
40. A method of filtering a feed according to clause 39 wherein the particles are or comprise fibres.
41. A method of filtering a feed according to clause 40 wherein at least some of said fibres have a longest linear dimension of from 1 μm to 1 mm.
42. A method of filtering a feed according to clause 40 or 41 wherein the fibres are derived from a substrate which has been treated in a treatment formulation comprising liquid.
43. Use of a filter according to any one of clauses 1 to 32 or a filter unit according to any one of clauses 33 to 36 for filtering a feed.