WO2004039475A1

WO2004039475A1 - A filter element and an attachment system for a filter element

Info

Publication number: WO2004039475A1
Application number: PCT/DK2003/000702
Authority: WO
Inventors: Jørgen POULSEN
Original assignee: Nordic Air Filtration A /S
Priority date: 2002-10-30
Filing date: 2003-10-15
Publication date: 2004-05-13
Also published as: DK174840B1; AU2003273766A1

Abstract

The invention relates to a filter element (1) for use in connection with e.g. gas turbines and comprising a hollow outer insert (2) in which and centrally with respect to the outer insert (2) a hollow inner insert (3) is arranged, said inserts (2, 3) comprising end edges to which a top flange (9) is attached at one end. The top flange (9) is made of foaming PU, and at least one insert (2, 3) is composed of a base material (4) to which a net (5, 7) is attached by one or more hot-melt lines (6), said base material (4) and said net (5, 7) being made of a combustible material. This provides a filter element which is exclusively based on combustible materials, whereby the filter element may easily be disposed of after use without having to be disassembled first. Further, the selected materials will result in optimum stiffening of the filter element. The invention also relates to an attachment system for a filter element.

Description

A FILTER ELEMENT AND AN ATTACHMENT SYSTEM FOR A FILTER ELEMENT

The present invention relates to a filter element for use in connection with e.g. gas turbines and comprising a hollow outer insert in which and centrally with respect to the outer insert a hollow inner insert is positioned, said inserts comprising end edges to which a top flange is secured at one end.

The invention also relates to an attachment system for a filter element.

Prior art

US Patent No. 4,720,292 discloses an air filter comprising a tubular housing consisting of an outer wall in which an outer inlet opening is arranged. A cover comprising a circular end wall with an axial outlet opening, and a pipe part extending outwardly around the axial outlet opening are positioned in connection with the one open end of the housing. An outlet element is arranged on the outlet opening, said outlet element being configured such that it may be applied to the outlet opening by snap action so that the outlet element is kept in position.

The other opening of the housing accommodates a circular outwardly extending flange with which a removable cover is connected.

A tubular filter element is placed co-axially with the housing, comprising an inner insert and an outer insert which, together with the outer wall of the housing, constitute a distribution chamber for the incoming air. A paper filter is disposed between the inner and outer inserts.

The housing, including the inlet opening, is made. of a plastics material in a known manner, and in order to resist axial compression without collapsing, both the inner insert and the outer insert are made of perforated metal, whereby these inserts form the decided stiffening of the air filter.

A circular cover of urethane foam material, which has a relatively soft rub- ber-like consistency, is moulded for the closing of the one open end of the filter element and thereby attachment of the ends on the inner and outer inserts. The cover is connected with the removable cover by projections arranged on the circular cover. To maintain the centered position of the filter element in the housing, the diameter of the housing around the cover is essentially identical with the outer diameter of the cover.

At the other end, opposite the cover of the housing, the filter element is provided with a ring-like end cap of an elastomer material, such as e.g. urethane rubber material, which is moulded over the end edges on the outer and inner inserts as well as the paper filter, respectively. The end cap is compressed at its surface to provide an air seal between the end cap and the outlet element.

In the use of the filter, contaminated air is sucked into the inlet opening to the distribution chamber, where the air is subsequently distributed evenly across the outer surface of the filter element and is sucked through the paper filter to the inner filter element to be discharged through the outlet opening. All foreign particles carried by the incoming air will thus be captured by the paper filter.

US Patent No. 5,792,227 moreover discloses a filter device for the filtration of materials composed of particles from gas flows, e.g. air flows, where the filter device, in addition to being structurally circular, may correspondingly assume an oval shape, and where use is made of modified materials to avoid e.g. leakage and consequently a shorter service life. Three successively positioned areas, a first area, a central area and a third area, are arranged between the outer and inner inserts, the latter area being essentially identical with the paper filter disclosed in US 4,720,292. The first area adjoining the outer insert of the housing comprises a dust collec- tion zone consisting of a woven material which has a fibre size of the order of 20-45 μm, e.g. polyester fibres. The central area is constructed such that only 6-7% of the total substance can pass through, and may e.g. be made of several composite polyester types.

In the use of the filter, this differs from the filter described in US 4,720,292 primarily in being more effective, as particles of varying sizes can be captured, whereby also an extended service life of the filter is achieved.

These known filters are primarily constructed for use/arrangement in motor vehicles where versatile filtration is needed, and are thus not constructed for use in connection with gas turbines.

Further, only few components of the total filter are made of synthetic substances/materials. An environmentally friendly way of disposal of the filter, e.g. by combustion, is thus not possible, without the filter first having to be disassembled, which is a time-consuming and costly procedure.

The novel art

With the invention, it is desired to provide a filter element where all components are made of materials which may be disposed of in an environmentally friendly manner after completed use of the filter.

Further, it is desired to provide an attachment system for the filter element.

The novelty of the filter element according to the invention is that the top flange is made of foaming PU, and that at least one insert is composed of a base material to which a net is attached by one or more hot-melt lines, said base material and said net being made of a combustible material.

When the filter element is manufactured exclusively by using combustible materials, the filter element can be disposed of easily after use, and it is thus not necessary to disassemble it first.

The selected materials result in a simplification of the structure of the filter element, as the adhesion of the materials per se will cause optimum stiffening of the filter element.

Correspondingly, the composition of materials will mean that it is not necessary to have an extra layer of material between the two inserts to ensure optimum collection of dust particles.

Owing to the optimum stiffening of the filter element, the requirements with respect to an attachment system for such a filter element will be very low, as further stiffening is not necessary. Thus, the filter element per se consti- tutes a housing for the filter, which is otherwise only known from filter elements with a metal stiffening.

The invention will now be explained more fully with reference to the drawing, in which

fig. 1 shows an outer insert and an inner insert for a filter element according to the invention, and

fig. 2 shows an attachment system for the filter element shown in fig. 1. Embodiments

Figure 1 shows a filter element 1 according to the invention, comprising a hollow outer insert 2 in which a hollow inner insert 3 is disposed. In this embodiment, the outer insert 2 and the inner insert 3 are tubular with coinciding centre lines L.

The outer insert 2 is composed of a base material comprising a filter material 4 which is made of a synthetic substance/material, e.g. cellulose and polyester. An external net 5 is arranged around the filter material 4, said net being made of a synthetic substance/material, e.g. HDPE, High Density Polyethylene, or LDP, Low Density Polyethylene. The external net 5 is attached to the filter material 4 by a spiral-shaped, or otherwise shaped, hot- melt line 6 which, in addition to keeping the respective materials together, also serves to stiffen the outer insert 2 in a simple manner, thereby making it possible to avoid inexpedient materials for e.g. gluing and/or moulding for environmental considerations.

The inner insert 3 is basically constructed in the same manner as the outer insert 2, thus consisting of a base material (not shown in the drawing) comprising a filter material around which an internal net 7 is arranged. The internal net 7 is made of a synthetic substance/material, e.g. PP, Polypropylene, or HDPE, High Density Polyethylene, and, like the external net 5, is attached to the filter material by a spiral-shaped hot-melt line 6, where the hot-melt line 6, in this connection too, serves as a stiffening and can assume another shape, e.g. as stepwise circular lines.

The synthetic substances/materials incorporated in the structure of the respective inserts, the outer insert 2 and the inner insert 3, should exclusively be regarded as instructive/illustrative, it being quite conceivable that other synthetic substances/materials are advantageous for use. Furthermore, the inserts 2, 3 may comprise more or fewer layers of material, which comprise a single or more composite materials, just as the inserts 2, 3 may comprise identical or different types of materials, but, irrespective of the selection of materials and combination of materials, it is essential to the invention that all materials are made of a form of synthetic substance such that, following completed use of the filter, the materials may be disposed of by combustion.

The outer diameter of the inner insert 3 is smaller than the inner diameter of the outer insert 2, so that the positioning of the inner insert 3 in the outer insert 2 and partial closing of the filter element 1 will provide a space 8 for the collection of dust particles from the air sucked in.

For the partial closing of the open ends of the filter element 1 , a flange is attached at each end by means of a moulding compound, said flange being called top flange 9 and bottom flange 10, respectively. The moulding compound will thus be applied to the end edges of the outer insert 2 and the inner insert 3, respectively, whereby the moulding compound will additionally bring about a stabilization of the inner insert 3.

Each flange 9, 10 assumes a shape according to the configuration of the inner insert 2 and the outer insert 3, respectively. In this embodiment, both the top flange 9 and the bottom flange 10 are thus shaped as a ring with a radial thickness which corresponds to the difference between the outer di- ameter of the outer insert 2 and the inner diameter of the inner insert 3. The remaining opening (not shown in the drawing) will hereby serve as the outlet opening of the filter element 1 where the cleaned air is discharged.

In this embodiment, both flanges 9, 10 are made of foaming PU, Polyure- thane, but may conceivably also be made of another material or of composite synthetic substances/materials. Similarly, foaming PU is used as a moulding compound, but here, too, another type of compound may conceivably be used. It is essential to the invention that flanges 9, 10 as well as moulding compound are of one or more synthetic substances/materials.

In connection with the mounting of the filter element 1 , where it is important that the admitted air does not leak out of the filter element 1 , a gasket/seal (not shown in the drawing) is used, which likewise comprises a synthetic substance/material, e.g. foaming PU. An embodiment where gasket and flange are formed integrally and of the same material, will be preferred, but is not a requirement.

The outer insert 2 as well as the inner insert 3 may basically assume any shape, e.g. conical. The conical configuration will cause one flange, preferably the bottom flange 10, to have a smaller diameter than the top flange 9. With the greatest cross-section oriented toward the suction side, the conical configuration will thus cause the cross-section to increase through the filter, whereby the speed of the air decreases.

Figure 2 shows an attachment system 12 to which the filter element 1 is attached. The attachment system 12 is made of a metallic or other hard material and comprises an upper attachment part 13 and a lower attachment part 14 relative to the upper attachment part 13, where the connection between the two attachment parts 13, 14 is provided by a suspension means 17.

In this embodiment, the upper attachment part 13 comprises a flange which, on the side oriented toward the lower attachment part 14, comprises defined edges 19 which are mutually spaced by a distance corresponding to the external width of the top flange 9 of the filter element, so that the edges 19 engage with and support the sides of the top flange 9. A V- shaped suspension member 18 forming part of the suspension means 17 is positioned between the defined edges 19 and is oriented in the same direction. The suspension member 18 is attached to the flange 13 e.g. by spot welding, and a mounting member 22 is secured opposite the suspension member 18 for the attachment of the attachment system 12.

The lower attachment part 14 comprises a plate with an opening 20, and two defined edges 19 having the same mutual spacing as the defined edges 19 on the upper attachment part 13 are arranged on the side of the plate 14 which is oriented toward the upper attachment part 13. The edges 19 thus correspondingly engage with and support the sides of the bottom flange 10. A hooked rod 15 is inserted through the opening 20, with the hook part 11 arranged in the suspension member 18. The hooked rod 15 thus forms another part of the suspension means 17.

As indicated by the name, the hooked rod 15 comprises a hook and a rod, said rod having threads 16 at its free end, i.e. opposite the hook part 11 , and when the hook part is thus arranged in the suspension member 18 (indicated by dotted line), the lower attachment part 14 is attached to the upper attachment part 13 by screwing on a wing or fly nut 21.

The configuration of the upper attachment part 13 and the lower attachment part 14, respectively, should be regarded as illustrative rather than an exact embodiment of the invention, since these attachment parts may very well be configured differently.

Correspondingly, the suspension means 17 may be formed by other solutions, e.g. by screw devices or by a wall which adjoins the inner insert and which thus constitutes an additional stiffening.

Claims

PATENT CLAIMS

1. A filter element (1) for use in connection with e.g. gas turbines, comprising a hollow outer insert (2) in which and centrally with respect to the outer insert (2) a hollow inner insert (3) is positioned, said inserts (2, 3) comprising end edges to which a top flange (9) is attached at one end, characterized in that the top flange (9) is made of foaming PU, and that at least one insert (2, 3) is composed of a base material (4) to which a net (5, 7) is attached by one or more hot-melt lines (6), said base material (4) and said net (5, 7) being made of a combustible material.

2. A filter element (1) according to claim 1, characterized in that a bottom flange (10) is attached to the end edges at the other end of the inserts (2, 3), said bottom flange (10) and said top flange (9) extending at respective ends between the end edge on the outer insert (2) to the end edge on the inner insert (3) and attached to these by a moulding compound of foaming PU.

3. A filter element (1) according to claim 1 or 2, characterized in that the outer diameter of the inner insert (3) is smaller than the inner diameter of the outer insert (2) to provide a space (8) for the collection of dust particles from the air sucked in.

4. A filter element (1 ) according to claim 1,2 or 3, characterized in that the flange (9), present at the end of the filter element (1 ) which discharges clean air, has a larger diameter than the flange (10) present at the opposite end of the filter element (1 ), so that the filter element (1 ) assumes a conical shape.

5. A filter element (1) according to any one of the preceding claims, characterized in that the base material (4) comprises a filter mate- rial, e.g. cellulose or polyester.

6. A filter element (1) according to any one of the preceding claims, characterized in that the net (5, 7) is made of e.g. HDPE or LDPE.

7. An attachment system (12) for a filter element (1) according to claims 1- 6, ch a racterized in that the attachment system (12) is made of a metallic or other hard material comprising an upper attachment part (13) and a lower attachment part (14) relative to the upper attachment part (13), said lower attachment part being connected with the upper attachment part

(13) by a suspension means (17).

8. An attachment system (12) according to claim 7, cha racterized in that the upper attachment part (13) comprises a flange with defined edges (19) for engagement with the sides of the top flange (9).

9. An attachment system (12) according to claim 7, characterized in that the lower attachment part (14) comprises a plate with an opening (21) as well as defined edges (19) for engagement with the sides of the bottom flange (10).

10. An attachment system (12) according to claims 7-8, characterized in that the suspension means (17) comprises a V-shaped suspension member (18) as well as a hooked rod (15) for arrangement in the sus- pension member (18), said suspension member (18) being positioned between the defined edges (19) of the flange on the upper attachment part (13), said hooked rod (15) being arranged in the opening (20) in the lower attachment part (14).