WO2007106019A1

WO2007106019A1 - A device anchoring a filtering net in relation to a support

Info

Publication number: WO2007106019A1
Application number: PCT/SE2007/000244
Authority: WO
Inventors: Johan Rasmussen
Original assignee: Johan Rasmussen
Priority date: 2006-03-15
Filing date: 2007-03-14
Publication date: 2007-09-20
Also published as: SE0600568L; SE528698C2

Abstract

The invention refers to a device provided with means anchoring a filtering net in relation to a support or a rack. The invention is provided with water draining means. Said means are arranged to convey water away from the part of the net surface which is blinded or shielded by said anchoring device to one part of said net surface which is not blinded by said anchoring device. Preferred is an embodiment wherein said device is provided with an active, filtering surface, which is larger than the net surface which is blinded or shielded by said anchoring means.

Description

A device anchoring a filtering net in relation to a support

The invention relates to a device provided with means, for example a fillister screw, anchoring a filtering net in relation to a support or a rack. When separating particles from primarily a fluid, for example when separating particles or fibres constituting basis for, for example, paper pulp, one is aiming at, partly, to collect on a surface of a filter the fibres or particles and, partly, to drain away the fluid preferably centrally between two filters, attached to a support, for example a sector of a circle. After such separation, the pulp of fibers or particles is removed from the surfaces of the filters.

To secure and/or attach a net, either made of, for example, yarns of metal or of plastic, in relation to said support or rack is annoying. On one hand, as large as filtering surface as possible is desired in order to speed up the filtering process but if too large portions of the filter is badly anchored in relation to the support, the filter is subjected to varying loads, on one hand during filtering primarily by a heavy force acting against the support and on the other hand when the pulp is removed from the filter, by means for exemple of water or air under high pressure, during which treatment the filter is subjected to heavy, in directions alternating pressure loads. Still worse the filter or filters are anchored in the support -- in the rack or sector - the larger forces - amplitudes -they are subjected to. In other words, the filtering capacity of the filter and the capacity thereof to withstand the loads in question without being fatigue and break too quickly constitute opposing features, at least up to now.

One technical possibility to enlarge the filtering surface of the filter is to fold - or plait - it but a folded filter is as such even more sensitive to how well it is anchored in relation to the support, as the deviation amplitudes of the filter tend to be large at alternating treatments to remove the collected paper pulp, for example, by means of customary used pressurized air or pressurized water. Frequently, the outer edges of for example a circle sector are used to attach the filters in relation to the sector support, for example by means of rulers, applied to the filters, and in such a case, the filters are only secured in their outer edges. In such a case, essentially all of the filtering surface will be able to flex outwardly with maximal amplitude. In spite of the fact that such rulers to a high degree reduce or blind the transfer of water at the edges of the support, collections of, for example, pulp fibres are created also at said edges, which collections under certain instances can spread to such extent that they will cooperate with pulp fibres collected on the main surfaces of the filters in a continuous cake around the two filters of the whole circle segment or sector. Such a contiuous cake of fibres or particles are difficult to remove by means of water pressure or air pressure and constitutes as such an unnecessarily large load on the filters.

In order to reduce said kind of collections of particles on unintended locations, for example around the edges of the segment, at present a so called blinding is used, wherein for example a narrow ribbon, as such not permeable to water, is applied around the active filtrating surface of the filter. Said blinding results, however, in that the active, filtrating surface of the filter is reduced correspondingly, usually to about 95%.

If one uses a number of, for example, screwed washers or similar means to secure the filtrating nets of the active, filtration surfaces in relation to the support, such washers should of course blind off - or shield - surfaces against filtrating actions corresponding to the surface extensions of said washers over the filtrating net surfaces. The filtration capacity of said nets would consequently be reduced but the durability of the filters would be increased. The present invention is aiming at anchoring filtrating nets in relation to a support or a rack such that the nets are remained in position without being moved in any essential meaning during loading and are, thus, not subjected to unnecessary fatigue of material and without blinding off the filtration surfaces of the nets in any essential way.

In order to solve the problems specified above, the device according to the preamble of the present specification is, according to the present invention, provided with water draining means, which are arranged to convey fluid away from the part of the net surface which is blinded or shielded by said anchoring device to one part of said net surface which is not blinded by said anchoring device.

Further details of and advantages with the present invention are apparent from the appended claims and from the description below in connection with the enclosed drawings, of which Fig. 1 in a perspective view is showing a net with a number of anchoring or holding devices, principally shown and distributed, Fig. 2 shows in a perspective view a first embodiment and applied example of the invention in connection with two planar nets, Fig. 3 shows in a perspective view an embodiment of the present invention adapted to a folded or waveshaped net, Fig. 4 shows, in a heavily enlarged scale, an essentially round washer in a further embodiement of the invention and Fig. 5 shows still another embodiment in a perspective view, for exemple, as a list having three sides. In Fig. 1 are disclosed in perspective view several different devices intended to hold or secure a net 1 in relation to a rack or support, not shown therein, which rack or support on its other, opposing side usually also is provided with a net, corrsponding to the net shown in the Figure. Such a rack or support is usually included in a larger separation plant as a segment or sector of a circle in order to - by means of the nets applied thereon - separate, for exemple, paper pulp from liquid. The present invention is, however, not limited to said application but is generally applicable to separation of particles and fibres from liquid and/or from gas. The devices as disclosed in Fig. 1 are anchored or secured in relation to the support by means of, for example, self-tapping fillister screws, rivets, snap braces or by means of any other, suitable attachment means. For example, the round washers 2-9 disclosed in Fig. 1 are, preferably, each provided with a centrally located screw, not shown in Fig. 1, which screw cooperates via the support, not shown in Fig. 1, with the net, located on the other side of the support not shown in Fig. 1, where a corresponding washer with suitable, to said screw adapted hole is located and aligned with related washer, through which tightening of said screw tightens said nets on either sides of the support against the latter. Alternately, said screw can of course directly be driven solely into the support, which screw preferably creates its own hole and threading. The round washers 2 - 9 are spread and distributed over the surface of the net 1 such that the surfaces of the net 1 which are not directly anchored via the washers 2-9 are relatively small in size, wherein lower loads on the nets are created due to the fact that the forces they are subjected to have less possibility to influence the nets.

In a second embodiment of the attachment devices, the last ones are shaped as elongated bodies 10-15, which similar to the washers 2-9 might be connected to corresponding bodies - not shown in Fig. 1 - which are cooperating via the support, not shown in Fig. 1 , with the net located on the other side of the support, not shown, wherein a corresponding body with suitable, to said screw adapted hole is located and aligned with the related body. Preferably, a fillister screw is screwed from each direction on a mutually distance between two opposing bodies creating the result that the bodies 1 0 - 15 and corresponding, not shown, opposing bodies, respectively, are mutually secured and kept in positions relatively to the nets and to the support. A third embodiment of the attachment devices are disclosed through lists 16, 17, which are located along several edges of the net, for example, along the longer sector sides, see Fig. 1, and along the curved edges of the nets, not shown in Fig. 1. Said lists 16, 17 might, for example, be connected to corresponding lists of a net, not shown in the drawing, and opposing said net 1 on the opposing side of a support or a rack by means of, for example, through running screws, not shown in Fig. 1.

All said devices 2-17 according to Fig. 1 shield or blind parts of the active, through-running surface (the filtering surface), wherein the capability of the net to convey away fluid is reduced corresponding to the abutting or projected, aggregated surfaces of the devices 2-17 againt the net 1, seen in the through-running direction of the net. If, however, the elongated bodies 10-15, for example, are designed and shaped as are sketchy disclosed in Fig. 2, the advantage is created that fluid fran the blinded surfaces of the attachment devices 10 and 22, respectively, is transferred to such parts of the nets 1 and 21, respectively, which are not shielded or blinded by the elongated bodies.

The elongated bodies 10-15 comprise according to Fig. 2, for example, fluid draining means 101-124 in the shape of cross to the elongated body running, mutually parallel open channels 101 - 124, which are directed away from the elongated body and the cross sections of which are shaped as funnels, cones, trapezoids or bowls, for example. Preferably, said channels 101- 124 are also widened in cross sections toward their outlets to the net 1. Furthermore, said bodies 10-15 may also be provided, if required or requested, with through running holes 125-134 and 135- 144 in sizes adapted to advantage to the smallest sizes of the particles or that the holes 1 25 - 144 instead are chosen to emerge in the attachment devices at levels corresponding to the bottoms of the channels 101-124. As further supplements, said bodies 10-15 can be provided with further fluid draining means, not shown in Fig. 1, which means are running angled to or located in different angles in relation to said mutually parallel running channels 101-124. The numbers of channels and, if present, of through running holes should be relatively large and are chosen primarily in relation to the extensions of the elongated bodies in said last mentioned direction. The distance between the banks of each channel 101-124 correspond to advantage to essentially the mesh openings of the nets 1 and 21 in order that the smallest particles should be collected by the banks of the channels 101-124.

If required or desired, the banks of said channels 101-124 are supplemented with cross over said banks running, thin rods - not shown in the drawings. Said rods are, if present, mutually separated essentially corresponding to the mesh opening of the nets 1 and 21.

Said elongated bodies 10-15 are also provided with, for example, two attachment holes 145 and 146, of which said first mentioned hole 145 may be designed so countersinked that a n adapted screw head, for example, a self-tapping fillister screw is contained therein and in that said last mentioned attachment hole 146 is adapted in size to cooperate with the threaded part of a corresponding second fillister screw. The two fillister screws used but not shown in Fig. 2 embodiment have in present case been sized in length such that they bridge the distance from, for exemple, the elongated bodi 10 to the opposing, elongated body 22, which body 22 in said elongated direction is mirror shaped in relation to the body 10. In such a way, said screws when tightened towards each other hold the intermediate nets 1 and 21 against the intermediate support or circle segment, not shown in Fig. 1, preferably without extending outside the outer surfaces of the bodies 10 and 22.

Please note in this context that the elongated bodies 10 and 22, respectively, according to Fig. 2 are designed identically and are shaped vaulted or in any other, suitble way made expanded or enlarged in surface compared to the surface which is blinded or shielded in the filtering nets 1 and 21, respectively. Thus, it is secured partly that conveying away of fluid always is taking place via said channels 101-124 and, if applied, also via said holes 1 25 - 144, partly that at least as large as or a larger surface is provided for collecting the particles intended than if said elongated bodies not were present.

In Fig. 3 in perspective view, an embodiment of the invention is shown adapted to a folded or wave-shaped net 1. The elongated device 10 has here only been provided with a contersinked hole 1 45 for attachment by means of, for example, a screw but its side turned towards the net has here been adapted, for example, to the valley shape of the net 1. The attachment device opposing the elongated device 10 - not shown in Fig. 3 - cooperating with said screw is adapted in shape to how the the second net, not shown in Fig. 3, is designed at that location, normally the second net is shaped as a bulge or top, in which case the opposing device at its side turned against the net should be shaped as a bowl. The means conveying away fluid are designed equivalent with the corresponding details of the devices 10 and 21 according to Fig. 2.

The round attachment devices 2-9 shown in Fig. 1 can, advantageously, for example be designed as disclosed by Fig. 4, shown in large scale, however, than in reality in order to expressly show how the round attachment devices may be shaped. Also in this embodiment, the surface of each attachment device located closest to the net 1 or 21 has a flat surface, provided the net is flat, and a corresponding shaped surface if the net is folded or bent. The essentially round attachment devices 2-9 are all provided with a preferably centrally located, countersinked hole 145 in order to secure each attachment device relatively to the support or rack for the nets by means of suitable devices. Furthermore, the fluid conveying means could be designed equivalently with the attachment devices 10 and 21 according to Fig. 2. The embodiment according to Fig. 5 shows an essentially three- sided list 16 or 17 used according to the embodiment in Fig. 1. Said list can be located along all edges of the nets 1 and 21, respectively, but preferable along its side edges and along the edges of the circle segment. The fluid conveying means 101-131 are directed and open toward the middle of each net 1 or 21 but the opposing ends are preferable closed. The fibres or particles which normally without lists tend to be collected on the edges of the filters 1 and 21 will in present case effectively be collected by the lists 16, 17, which also will facilitate removal of the collected particles. Furthermore, the fluid conveying means can be designed equivalently to the devices 10 and 21 of Fig. 2.

Modifications are of course possible within the scope of the appended claims. The contents of the claims are regarded as being part of the description as well.

Claims

1. A device provided with means, for example a fillister screw, anchoring a filtering net (1, 21) in relation to a support or a rack, c h a r a c t e r i z e d in that said device is provided with water draining means (2-9, 10, 22, 16, 17), which are arranged to convey water away from the part of the net surface which is blinded or shielded by said anchoring device to one part of said net surface which is not blinded by said anchoring device. 2. The device according to Claim 1, c h a r a c t e r i z e d in that said device is provided with an active, filtering surface which is larger than the net surface which is blinded or shielded by said device.

3. The device according to Claim 1 and 2, respectively, c h a r a c t e r i z e d in that a number of devices (2-9, 10-15, 16, 17) having water draining means are distributed along the surface of the whole net (1 and 21, respectively).

4. The device according to Claim 1 and 2, respectively, c h a r a c t e r i z e d in that said devices (16, 17) having water draining means are located along at least some of the edges of said net (1 and 21, respectively).

4. The device according to any of the preceding Claims, c h a r a c t e r i z e d in that said water draining means are shaped as channels with openings directed outwardly (101-124, 101-117 and 101-131, respectively) each having cross-section like a funnel, a cone or like a trapezoid.

6. The device according to any of the preceding Claims 1-5, c h a r a c t e r i z e d in that said water draining means (101-124, 101-117 and 101-131, respectively) are located mutually parallel. 7. The device according to Claim 6, c h a r a c t e r i z e d in that said water draining means consists of a number of mutually parallel channels (101-124, 101-117 and 101- 131, respectively), which are intersected by a number of mutually parallel channels as well. 8. The device according to any of the preceding Claims, c h a r a c t e r i z e d in that said water draining means or channels (101-124, 101-117 and 101-131, respectively) are each deeper in one of the ends than in the other, which one end is opening into said net. 9. The device according to any of the preceding Claims 5-8, c h a r a c t e r i z e d in that the mutual distance between the banks or sides of each of said channels (101-124, 101-117 and 101-131, respectively) essentially corresponds to the mesh opening of the net (1, 21) used.