WO2016024909A1

WO2016024909A1 - Filter support, filter sector part and sector part

Info

Publication number: WO2016024909A1
Application number: PCT/SE2015/050869
Authority: WO
Inventors: Johan Rasmussen
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-08-14
Filing date: 2015-08-12
Publication date: 2016-02-18
Anticipated expiration: 2017-02-14
Also published as: SE538253C2; SE1450946A1

Abstract

Filter support (10) for a filter sector part (31), which filter support (10) is formed with a surface extension comprising alternating, essentially parallel ridges (11) and parallel valleys (12), the entire surface extension of the filter support (10) inside a sector frame (21) included in the filter sector part (31) being provided with said ridges (11) and valleys (12), wherein at least one of the two radial edges (19, 20) of the filter support (10) is provided with recesses (15) which between themselves form support protuberances (16). A filter sector part (31 ) provided with such a filter support (10) and a sector part (50) provided with such a filter sector part (31).

Description

A FILTER SUPPORT, A FILTER SECTOR PART AND A SECTOR PART

Technical Field

The present invention relates to a sector part for a filtering, preferably rotary arranged filter disc. This sector part comprises a filter support mounted in a sector frame for the through transportation of liquid flowing through a filter of suitable design, which is abutting against the filter support, and further into a centre channel via an outlet channel in the sector frame. Background of the Invention

In the pulp and paper industry, it is common to use disc-shaped rotary vacuum filters, which are placed axially in series with the purpose of cleaning liquids, above all water in the pulp and paper industry. Said rotary discs are each one built-up by a number of assembled disc segments, each one of which is called a sector part. Each sector part consists of a sector frame, a filter support, and a filter over the surface of the entire filter support, and usually on both sides of the filter support. Each sector part is furthermore provided with an outlet channel for the filtered liquid, which is transported further into a central shaft or central rotor or alternatively into peripheral tubes on or to which the sector parts are mounted. The transport of liquid through the filter parts is provided by a vacuum, which implies that the filter surface is pressed against the filter support.

Prior art in the field is seen in the Swedish patent SE 531539, which shows a sector part provided with a filter support designed as a pleated metal mesh, which pleats are oriented perpendicularly in relation to the radial extension of the sector part.

Furthermore, US 5,647,982 shows additional background of the invention and a corresponding sector part comprising a filter support support formed with parallel ridges and valleys oriented so that a ridge or valley is parallel to the radial extension of the sector part. The ridges and the valleys of US 5,647,982 are formed by the filter support from a flat metal disc being bent with sharp V-shaped ridges and valleys between which flat sides tangential flow in the sector part is limited. The material of the filter support is stainless steel. The radial flow in the sector part takes place between the ridges and between the valleys, respectively, and in the radial direction in formed channels at the two side edges of the sector part by the fact that the support does not extend all the way out to the edge of the sector part but is welded to the frame profile of the sector part at a distance from the edge.

By the fact that the filter supports are formed of metal, a fatigue bending of the metal is obtained. Particularly for such filter supports that are welded and bent meshes, failure is obtained in the welds, wherein the wires rub holes in the filters. Correspondingly, sharp corners of other types of filter supports gnaw through the filters and these have to be replaced to maintain the filtering power. The Object of the Invention

The object of the invention is to provide a filter support, which is easy to produce and which is kind to the filters, and which allows at least the same flow rates through the sector parts as previously known filter supports.

The object is furthermore to provide a filter support, which in addition can constitute support to different types of filters, such as, for instance, bag-like synthetic filters and stainless metal filters, which both may be flat as well as pleated.

The object is furthermore to provide a filter sector part comprising such a filter support.

In addition, the object is to provide a sector part having such a filter sector part for a filter with a pressure difference, for instance a vacuum filter for liquid cleaning.

Summary of the Invention

By the present invention, as the same appears in the independent claims, the above-mentioned objects are met wherein said disadvantages have been eliminated. Suitable embodiments of the invention are defined in the dependent claims.

The terminology used henceforth is that a sector part consists of a filter sector part and a filter; that a filter sector part consists of a filter support and a sector frame; that a sector frame consists of support profiles, where each profile preferably is in the form of a U-profile, an outlet channel and connections to a centre shaft or to connections of other known constructions, for instance rotor constructions or constructions having peripheral tubes. The invention concerns a filter support for a filter sector part for a filter to clean liquids. The filter support is formed with a surface extension comprising alternating, essentially parallel ridges and parallel valleys, the entire surface extension of the filter support inside a sector frame included in the filter sector part being provided with said ridges and valleys. At least one of the two radial edges of the filter support is provided with recesses which between themselves form support protuberances. Said filter support is intended to be used in filter units where the transportation of the filtered liquid takes place either by a central shaft, by a central rotor or by peripheral tubes on or to which the sector parts are mounted.

By the expression "primarily/essentially", throughout in the application reference is made to the fact that the angle, however, may vary ± 5°.

The invention concerns a filter support for a filter sector part, which filter support is formed with a surface extension comprising essentially parallel ridges and parallel valleys oriented so that a ridge or a valley is primarily parallel to the radial extension of the filter support in the filter sector part. The entire surface extension inside a sector frame included in the filter sector part is provided with said ridges and valleys. The two radial edges of the filter support are provided with recesses which between themselves form support protuberances. The recesses allow a radial flow between the parallel ridges and the valleys along the radial side edges of the filter support, which in turn improves the radial flow of the entire sector part. Thus, an overflow between two adjacent channels can take place by said protuberances at the side edges.

In one embodiment of the invention, the surface extension of the filter support is either pleated or wave-shaped. Particularly this wave-shaped design of the filter support represents a surface-extended abutment against a filter surface, which is kind to the filter surface and thereby the filter, when the same is pressed against the filter support. Said surface-extended abutment contributes to extending the service life of the filter and thereby decreased the maintenance need of the sector part.

In one embodiment of the invention, the section surfaces of the filter support at a tangential section through the wave shape follow a sine curve, preferably according to the formula y = sin x and where the amplitude of the curve corresponds to half the distance between the insides of the filter surfaces. Such a shape of the filter support implies on one hand a cautious abutment of the filter against the filter support and a flow through the sector part that minimizes turbulence caused by the filter support.

In one embodiment of the invention, the support protuberances have a length corresponding to a simultaneous abutment against the sector frame when the filter support is mounted in the sector frame. Such support protuberances that all abut against the sector frame increase the stability of the sector part and simultaneously represent a reduction of vibrations in the filter support at its connection to the sector frame.

In one embodiment of the invention, the abutment takes place against the radial inside of the sector frame. In U-shaped profiles, such an abutment implies that the protuberances do not primarily rest against the branches of the profiles but against the inside of the web.

In one embodiment of the invention, the recesses and the support protuberances, respectively, have a uniform spacing and are arranged along the two radial edges of the entire filter support. Such a design represents an efficient continuous manufacturing method by the fact that recesses and protuberances continuously can be cut out, for instance using water cutting.

In one embodiment of the invention, the filter support is manufactured from a homogeneous polymeric material with or without reinforcement, preferably polypropylene or composite. Also acrylic plastic PEX or polycarbonate is possible polymeric materials. Such materials are available as standard goods and may be in the form of a blank for a filter support. The blank only needs to be end cut and be edge cut to obtain a finished filter support. This represents both a quick and inexpensive production process of a filter support. Also stainless steel or polymeric materials reinforced with carbon fibre / glass fibre may be used as material for a filter support within the scope of the invention.

In one embodiment of the invention, the filter support is provided with a number of side passages distributed over the surface extension of the filter support to allow cross-flow between the channels formed by the wave-shaped filter support. In a homogeneous polymeric material, the surfaces are tight and allow no cross-flow, but by providing the filter support with side passages, a certain cross- flow is allowed. The flow size of the cross-flow can be determined by selecting a number of side passages of the filter support. Preferably, the number of side passages is surface-wise higher closer to the outlet channel because of an increased flow density. In a special case of this embodiment, the filter support is shaped as a pleated or wave-shaped perforated plate, which, by its protuberances located at the edge , rests against the inside of the sector frame. However, said plate is not welded against the sector frame but is loosely inserted in the sector frame to facilitate replacement and maintenance. Also designs having fixedly mounted filter supports are feasible within the scope of the invention.

The invention also concerns a filter sector part comprising a sector frame in the form of U-profiles, the branches of which are oriented inward toward the centre of the sector part. The filter sector part is in this connection provided with a filter support according to any one of the embodiments presented above, which filter support is mounted in the U-profiles. By the sector frame being wedge- shaped, the filter support can easily be inserted radially into the sector frame by the fact that the outer limit profile of the sector frame can be dismounted/mounted. Should this limit profile not be dismountable, it can be cut off and again be welded in place after replacement of filter support.

The invention also concerns a sector part comprising a filter sector part according to the above together with a filter. The filter is, for instance, designed as a bag of a synthetic material, which is slipped over the entire filter sector part, the filter being provided with mounting devices, for instance in the form of zip fasteners. Such a type of filters can be replaced without dismounting the sector frame.

In one embodiment of the sector part, the filter is designed as a flat or pleated synthetic filter having a surface extension over the side of the entire filter support.

In one embodiment of the sector part comprising the filter sector part, the filter is formed as a flat or pleated filter disc, which is built-in in the sector frame or added on the sector frame and which is made of stainless metal mesh provided with mounting devices, for instance in the form of through screw-and-nut joints. In such an embodiment, the entire filter support is removed together with the filter after the sector frame has been dismounted.

In one embodiment of the sector part with the filter sector part, the filter sector part comprises a first sector member and a second sector member, which sector members border to each other via an H-profile, at least one sector member being provided with a filter support according to what has been described above.

Brief Description of the Drawings

Now, the invention will be described in more detail, references being made in connection with the accompanying drawing figures. For the sake of the clarity, section indications have been omitted in the given section views.

Figure 1 shows a filter support according to the invention.

Figure 2 shows a sector frame according to the invention.

Figure 3 shows a filter sector part with the filter support mounted in a sector frame according to the invention.

Figure 4 shows a radial section through a filter sector part according to the invention.

Figure 5 shows the filter sector part provided with a filter of stainless cloth.

Figure 6 shows the filter sector part provided with a filter of bag type.

Figure 7 shows a tangential section A-A according to Figure 5 through an embodiment of the invention.

Figure 8 shows a tangential section B-B according to Figure 6 through a further embodiment of the invention.

Figure 9 shows the embodiment in Figure 8 under vacuum.

Figure 10 shows a second embodiment of a filter support according to the invention.

Figure 1 1 shows a radial section through a filter sector part having a filter support according to Figure 10.

Figure 12 shows a tangential section through a mounted filter support according to the second embodiment.

Figure 13 shows a first variant of a double filter sector part each one

having the respective filter support according to Figure 1 .

Figure 14 shows a second variant of a double filter sector part each one having the respective filter support oriented parallel to one of the radii of the sectors.

Figure 15a shows a third embodiment of a filter support according to the invention. Figure 15b shows a fourth embodiment of a filter support according to the invention.

Figure 16 shows a third variant of a double filter sector part each one having the respective filter support oriented tangentially in each sector.

Figure 17 shows a section analogous to the section A-A shown in Figure

5 and Figure 7 having a filter support according to Figure 15a.

Description of the Invention

Figure 1 shows a first design of a wave-shaped filter support 10 having a consisting of essentially parallel ridges/wave crests 1 1 and parallel valleys/wave troughs 12 having a surface extension over the surface of the entire filter support. The ridges 1 1 and the valleys 12 are oriented so that the ridges and the valleys are essentially parallel to the radial extension of the filter support, i.e., essentially parallel to a symmetry line S from the inner edge 13 of the filter support to the outer edge 14 thereof. The filter support is essentially wedge-shaped with the narrow edge 13 thereof turned inward and the wide edge 14 thereof turned outward so as to from the outside be insertable into a sector frame. The filter support 10 is furthermore provided with recesses 15 between which support protuberances 16 are arranged. The embodiment according to the figure shows recesses with intermediate support protuberances distributed along the entire radial edges 19, 20 and with constant spacing between the recesses and the protuberances, respectively. In other embodiments of the filter support, another spacing may be suitable, and in further embodiments, the support protuberances 16 may be placed tighter inward toward the narrow edge 13 and looser out toward the wide edge 14. The filter support 10 is furthermore provided with a number of side passages 17 distributed over the surface extension of the filter support to allow cross-flow between channels 18 formed by the wave-shaped filter support.

Figure 2 shows a sector frame 21 for a filter sector part where the sector frame consists of U-shaped radial profiles 22, 23, which are interconnected by an outer limit profile 24, which in the embodiment illustrated may be fastened with screws in the radial profiles 22, 23. The radial profiles 22, 23 are connected inward to an assembly fitting 25, which surrounds an outlet channel 26. The entire sector frame 21 may be mounted to a centre shaft, not shown, having a centre channel by means of a connecting sheet 27.

Figure 3 shows a filter sector part 31 with the filter support 10 thereof according to Figure 1 and the sector frame 21 thereof according to Figure 2 assembled to the filter sector part 31 .

Figure 4 shows a radial section through the filter sector part 31 , the support protuberances 16 of the filter support 10 abutting against the outermost inside 41 of the U-shaped radial profiles 22, 23. By its protuberances, there is obtained a possibility of a radial flow between the channels formed by the wave shape. The radially flowing liquid passes the outlet channel 26 and further into the centre channel in the centre shaft, not shown.

Figure 5 shows a sector part 50 having an embodiment of the filter in the sector part 50, which in this embodiment is a flat stainless metal mesh 61 , which by screws 62 is screwed through the filters of both sides and through the filter support. For distribution of the screw force over the filter surface, the screws 62 are also screwed through surface enlarging mounting panels 63, which in the figure have been shown as stars. Said metal mesh may also be pleated.

Figure 6 shows an alternative embodiment of the filter of the sector part 50 in Figure 5, which in this embodiment consists of the sector part 50 having a filter sector part 31 , which is provided with a bag filter 51 covering the entire filter sector part 31 except the assembly fitting 25 and the connecting sheet 27. The bag filter may be flat or pleated.

Figure 7 shows a tangential section A-A through the sector part 50 shown in Figure 5 having the wave-shaped filter support 10 inserted between the two radial U-shaped profiles 22, 23 of the sector frame 21 . The filter sides 61 , 71 are held against the filter support 10 by means of the mounting panels 63, 73 and the screws 62 on both sides of the sector part and which extend through screw holes 74 in the filter support 10. As is seen in the figure, the support protuberances 16 abut against the inner surface 72 of the web of the U-profiles corresponding to the outermost inside of the U-profiles. Depending on the wave shape at the U-profile, the protuberances may also abut against either of the branches of the U-profile which corresponds to an alternative inside of the U-profiles.

Figure 8 shows a tangential section B-B through the sector part 50 shown in Figure 6 having the wave-shaped filter support 10 inserted between the two radial U-shaped profiles 22, 23 of the sector frame 21 . In this figure, the filter sector part is covered with a bag filter 51 , which has been sealed around the filter sector part in a suitable way, for instance by a zip fastener 81 or by shrinkage. The protuberances 16 abut in this embodiment also against the U-profiles 22, 23 in the same way as shown in Figure 7. In this embodiment, there are also shown two side passages 17 to allow cross-flow between channels 18 formed by the wave- shaped filter support 10.

Figure 9 shows how the bag filter 51 of the sector part 50 according to Figure 8 is pressed against the outsides of the wave crests 1 1 and wave troughs 12 when a pressure difference is created, for instance that a vacuum is applied inside the sector part 50. The bag filter 51 is pressed down into the channels 18 but is held back by the outsides of the wave crests 1 1 and wave troughs 12. By this pressing against the wave crests/wave troughs, a cross-flow can only be obtained through side passages 17 in combination with the recesses in the filter support.

Figure 10 shows a second embodiment of the filter support 10 which, like the first design, is provided with essentially parallel ridges/wave crests 1 1 and parallel valleys/wave troughs 12 having a surface extension over the surface of the entire filter support. The ridges 1 1 and the valleys 12 are in this embodiment oriented so that the ridges and the valleys are essentially parallel to one radial edge 19 of the filter support, which implies that a radial flow channel 101 is formed at this edge. The second radial edge 20 of the filter support is, however, formed with said recesses 15, between which support protuberances 16 are arranged, as previously mentioned. These recesses 15 form in this connection radial flow channels at said edge of the filter support.

Figure 1 1 shows a radial section through a filter sector part 31 having a filter support 10 according to Figure 10. The figure shows that the mounted filter support allows a radial liquid flow parallel to the filter support 10 at the first radial edge 1 10 of the filter sector part 31 and also a radial liquid flow through the recesses 15 of the filter support 10 at the second radial edge 1 1 1 of the filter sector part 31 .

Figure 12 shows a tangential section through a mounted filter support formed according to Figure 10. The figure shows that the filter support 10 at the first radial edge 1 10 of the filter sector part 31 abuts against the inner surface 72 of the web of the U-profile 22. The figure further shows that the support

protuberances 16 of the filter support 10 at the second radial edge 1 1 1 of the filter sector part 31 abut against the inner surface 72 of the web of the U-profile 22.

Figure 13 shows a double filter sector part 31 , which is constructed from a first sector member 31 a and a second sector member 31 b. The respective filter support of the sector members abuts against a radially directed H-profile 131 symmetrically placed in the filter sector part 31 . The two filter supports 10a, 10b are oriented in the respective sector member in the same way as previously shown in Figure 3, i.e., that the ridges 1 1 and the valleys 12 are oriented so that the ridges and the valleys are essentially parallel to the radial extension of the filter support, i.e., essentially parallel to a line from the inner edge 13 of the filter support to the outer edge 14 thereof. Furthermore, the inner radial edges of the two filter supports 10a, 10b abut against the web of the H-profile from a respective side.

Figure 14 shows a second variant of a double filter sector part 31 each one having the respective filter support 10a, 10b oriented parallel to one of the radii of the sector members 31 a, 31 b. Also this embodiment of filter sector part is provided with a centrally and radially running H-profile against the web of which the two filter supports 10a, 10b abut. The first filter support 10a abuts against the H-profile with its support protuberances while the second filter support 10b abuts against the H-profile with its entire parallel and radially directed edge in

accordance with what has been shown in Figure 1 1 .

Figure 15a shows a further embodiment of a filter support 10 having a tangential orientation of the essentially parallel ridges 1 1 and valleys 12 and which in that connection have an extension perpendicular to the radial symmetry line S of the filter support 10. The embodiment shows that only one side of the filter support is formed with said recesses 15 between which support protuberances 16 are arranged, like what has been shown in previous embodiments.

Figure 15b shows a further embodiment of a filter support 10 having a tangential orientation of the essentially parallel ridges 1 1 and valleys 12 like the orientation shown in Figure 15a. However, this embodiment is provided with said recesses 15 and said support protuberances 16 on the two radial edges of the filter support. Figure 16 shows a double filter sector part 31 , which is constructed from a first sector member 31 a and a second sector member 31 b. The respective filter support of the sector members abuts against a radially directed H-profile 131 symmetrically placed in the filter sector part 31 . The two filter supports 10a, 10b are oriented in the respective sector member in the same way as previously shown in Figures 15a and 15b. The filter supports 10a, 10b of said double filter sector part 31 may be formed with support protuberances and recesses according to either what has been shown in Figure 15a or shown in Figure 15b or with both these variants of filter supports, wherein one of the variants is placed in the first sector member 31 a and the second variant is placed in the second sector member 31 b.

Figure 17 shows a section through an embodiment analogous to the section A-A shown in Figure 5 and Figure 7 but mounted with a filter support according to Figure 15a. The figure shows that the filter support 10 at the second radial edge 1 1 1 of the filter sector part 31 abuts against the inner surface 72 of the web of the U-profile 22. The figure further shows that the support protuberances 16 of the filter support 10 at the first radial edge 1 10 of the filter sector part 31 abut against the inner surface 72 of the web of the U-profile 22.

Thus, as is seen in the above description of embodiments, the orientation of a mounted wave-shaped filter support in the different embodiments of a filter sector part may be: radial with the waves parallel to a symmetry line; with the waves parallel to a radial edge of the filter sector part; tangential with the waves perpendicular to a symmetry line of the filter sector part. Even if only these orientations of a filter support are shown and described, also other angles of the orientations of the filter supports may be suitable and are accordingly protected within the scope of the subsequent claims.

In all embodiments shown, also a radial flow is obtained along the U- profiles through the recesses formed between the support protuberances. In all embodiments within the scope of the invention, the support protuberances extend all the way in to the web of the radial profiles irrespective of whether they are designed as U-profiles or as H-profiles.

Claims

1 . Filter support (10) for a filter sector part (31 ), which filter support (10) is formed with a surface extension comprising alternating, essentially parallel ridges (1 1 ) and parallel valleys (12), the entire surface extension of the filter support (10) inside a sector frame (21 ) included in the filter sector part (31 ) being provided with said ridges (1 1 ) and valleys (12), characterized in that at least one of the two radial edges (19, 20) of the filter support (10) is provided with recesses (15) which between themselves form support protuberances (16).

2. Filter support according to claim 1 , characterized in that the parallel ridges (1 1 ) and the parallel valleys (12) are oriented either essentially parallel to the radial extension of the filter support (10) in the filter sector part (31 ) or essentially parallel to one of the radii of the filter support (10) in the filter sector part (31 ) or essentially perpendicularly to one of the radii of the filter support (10) in the filter sector part (31 ), and that the entire surface extension inside a sector frame (21 ) included in the filter sector part (31 ) is provided with said ridges (1 1 ) and valleys (12).

3. Filter support according to any one of claims 1 -2, characterized in that the surface extension of the filter support (10) is either pleated or wave-shaped.

4. Filter support according to claim 3, characterized in that the section surfaces of the filter support (10) at a section perpendicular to the ridges (1 1 ) through a wave-shaped filter support (10) follow a sine curve.

5. Filter support according to any one of claims 1 -4, characterized in that the support protuberances (16) have a length corresponding to a simultaneous abutment against the sector frame (21 ) when the filter support (10) is mounted in the sector frame (21 ).

6. Filter support according to claim 5, characterized in that the abutment takes place against the radial inside (41 ) of the sector frame (21 ).

7. Filter support according to any one of claims 1 -6, characterized in that the recesses (15) and the support protuberances (16), respectively, have a uniform spacing and are arranged along one or both radial edges (19, 20) of the entire filter support (10).

8. Filter support according to any one of claims 1 -7, characterized in that the filter support (10) is manufactured from a homogeneous polymeric material with or without reinforcement, preferably polypropylene or composite.

9. Filter support according to any one of claims 1 -7, characterized in that the filter support (10) is manufactured from a pleated plate.

10. Filter support according to any one of claims 8-9, characterized in that the filter support (10) is provided with a number of side passages (17) distributed over the surface extension of the filter support (10) to allow cross-flow between the channels (18) formed by the wave-shaped filter support.

1 1 . Filter sector part (31 ) comprising a sector frame (21 ) in the form of U- profiles (22, 23) the branches of which are oriented inward toward the centre of the filter sector part (31 ), characterized in that the filter sector part (31 ) is provided with a filter support (10) according to any one of claims 1-10 and mounted in the U-profiles (22, 23).

12. Sector part (50) comprising a filter sector part (31 ) according to claim 1 1 together with a filter (51 , 61 ), characterized in that the filter is designed as a bag filter (51 ), which is slipped over the entire filter sector part (31 ), the bag filter (51 ) being provided with mounting devices, for instance in the form of zip fasteners.

13. Sector part (50) comprising a filter sector part (31 ) according to claim 1 1 together with a filter (51 , 61 ), characterized in that the filter is designed as a flat or pleated synthetic filter having a surface extension over the side of the entire filter support (10).

14. Sector part (50) comprising a filter sector part (31 ) according to claim 1 1 together with a filter (51 , 61 ), characterized in that the filter is designed as a flat or pleated stainless metal mesh (61 ), which is provided with mounting devices (62, 63), for instance in the form of a through screw-and-nut joint.

15. Sector part (50) comprising a filter sector part (31 ), characterized in that the filter sector part (31 ) comprises a first sector member (31 a) and a second sector member (31 b), which sector members border to each other via an H-profile and that at least one sector member (31 a, 31 b) is provided with a filter support according to any one of claims 1-10.