AU686044B2 - A ventilator filter - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Filtercorp International Limited ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: A ventilator filter The following statement is a full description of this invention, including the best method of performing it known to me/us:- I1PI1Y 01U191 L II la This invention relates to ventilation filters and in particular to pocket bag ventilation filters.

Pocket bag filters are known which are intended to be secured in holding frames in ventilation systems. The prior art filters include bags having a number of pockets having walls constructed of filtration material with the adjacent pockets joined at the open ends. A filter bag header is provided which surrounds the mouth of the pocket filter bag, having dimensions to fit the holding frame, and also having supporting sections which hold and support in the required position the joins between adjacent pockets of the pocket filter bag. In prior art pocket filter bags these headers are formed integrally with the filter bag, for example it is most common for the header to be a moulded plastic or rubber material with the filter bag material either bonded to the rubber material or moulded at its edges into the rubber material during the moulding process, or fabricated in a permanently fixed manner from for example stainless steel, PVC or rubber.

Ventilation filters of this design are necessarily a throw-away item and after a period of use or when the pockets of the filter reach their operating limits of capacity the entire pocket bag filter is discarded and replaced. Given that the lifespan of the filter in many circumstances is only nine months, replacement of filters can be an expensive 20 running cost.

Therefore it is an object of the present invention to provide a pocket filter bag header which will at least go some way towards overcoming the above disadvantage, or will at least provide the public with a useful choice.

In a first aspect the invention consists in a pocket filter bag header comprising: a first rigid frame, having a surround portion and at least one support member spanning between points on said usurrou ortion, saidAsurround portion adapted to engage in use inside a filter housing, and said at least one support member adapted to be disposed at and under and to support the seams between adjacent pockets of a pocket filter bag, -2- Seconrd VywWa second rigid frame having a surround portion and at least one covering member seconk *rowiespanning between points on said urround portion, said at least one cover member adapted to be disposed at and over the seam between adjacent pockets of a pocket filter bag to in use hold the seams between adjacent pockets of a pocket filter bag between said support members and said cover members, and disengageable connecting means, connecting said surround portion of said first rigid frame against said surround portion of said second rigid frame.

In a second .aspect the invention consists in a ventilation filter comprising: a pocket filter bag having a plurality of pockets, adjacent said pockets joined by seams at their open ends, a first rigid frame, having a surround portion and at least one support member spanning between points on said surround portion, said surround portion adapted to engage in use inside a filter housing, and said at least one support member adapted to be disposed at and under and to support the seams between adjacent pockets of said pocket filter bag, a second rigid frame having a surround portion and at least one covering member spanning between points on said surround portion, said at least one cover member adapted en...i to be disposed at and over the seams between adjacent pockets of said pocket filter bag *i to in use hold the seams between adjacent pockets of said pocket filter bag between said 20 support members and said cover members, and disengageable connecting means, connecting said surround portion of said first rigid frame against said surround portion of said second rigid frame.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will 25 suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

The preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which; 0 ~r~t8 ~~"*~C~I"~~U111111111311 Figure 1 is an exploded perspective view of the pocket filter bag header of the present invention, Figure 2 is a partial cut-away top view of the pocket filter bag header of the present invention, Figure 3 is a cross-sectional view thluough section AA of the pocket filter bag header of Figure 2, and Figure 4 is a perspective exploded view of the ventilation filter of the present invention.

Referring to Figure 1, a filter bag header according to the preferred embodiment of the present invention is shown having a first rigid frame 1 and a second rigid frame 4 which are to be connected by connecting means 6, 3. Rigid frame 1 has surround portion 11, being in this instance a square structure and support members 2 which span between points on the surround portion 11 of the rigid frame 1, which in the embodiment shown span directly across the frame, dividing the frame into five equal rectangular portions.

Second rigid frame 4 as shown comprises a surround portion 14, which also has four equal sides, and covering members 5 which span between points on the surround portion 14 of rigid frame 4. As shown the covering members 5 are positioned to be complementary to o support members 2 when the frames 1, 4 are brought together and connected by disengageable connecting means 6, 3.

20 Referring to Figure 4, the apparatus of Figure 1 is shown including the pocket filter bag 15. In this it can be seen that when the frames 1. 4 are brought together the surround lip 18 of filter bag 15 is held between the surrcurd portions 11, 14 of frames 1, 4. Each of the pockets 16 of the bag 15 is disposed through one of the equal portions formed by S..the spanning support members 2, and as such when frames 1 and 4 are brought together 25 and connected, the support members 2 are adjacent the seams 17 between adjacent pockets of the pocket filter bag 15, and the covering members 5 are also adjacent the seams 17, but are on the opposite side of the filter material from the support members 2.

In use the pocket filter bag including header forms a ventilation filter for positioning in a holding frame and may be individually filtering in a ventilation duct or may be one of many filter units in a holding frame. In such holding frame, the filter is -4intended to have air flowing from dhe second rigid frame 4 side of the filter through the filter.

Referring to Figures 2 and 3, the filter bag header is shown with the first and second frame of the filter brought together and connected by connecting means 6, 3.

Referring in particular to Figure 3, it can be seen that the surround portion 11 of first rigid frame 1 comprises horizontal surface 8 and vertical surface 7 formed to produce the square frame. Similarly, it can be seen that the surround portion 14 of second rigid frame 4 comprises horizontal surface 9 and vertical surface 10. As shown in the drawing, the frames are preferably configured so that in bringing the frames together the vertical surfaces 7, 10 overlap, and in conjunction with the horizontal surfaces 9 and 8 form a Ushaped section. In use this U-shaped section serves to hold in place the pocket filter bag lip 18 (see Figure It can be seen also that in the preferred embodiment shown, the connecting means -for disengageably connecting the first frame 1 and second frame 4 are embodied as an elongate depression 3 formed in one of the overlapping surfaces (in the embodiment shown the vertical surface 7 of surround portion I11 of rigid frame 1) and a complementary protrusion 6 formed in the other overlapping surface (in the embodiment shown the vertical surface, 10 of surround portion 14 of second rigid frame Preferably at least two such connections are provided on different sides of the frame. Up to four such connections may be provided, with one provided on each side of the header. In the 20 embodiment illustrated, two connections are provided on opposed sides of the frame.

Preferably these opposed sides are perpendicular to the support members 2 so that the deformities assist the rigidity of the frame. Other forms of disengageable connecting means are possible, however it has been found that a solution such as the one depicted is adequate to secure the two rigid frames during transport and manipulation, and once in place in the holding frame the two frame portions are further secured by the holding frame itself. Further to this, the configuration shown is exceptionally easy to disassemble when required.

Also shown in Figure 3 is support member 2, which is shown welded to surround portion 11 of first rigid frame 1, and covering member 5, which is shown welded to surround portion 14 of second rigid frame 4. Covering member 5 for convenience is preferably flat where it joins the surround portion 14, however for effectiveness it is preferably complementary to the support member 2 across most of its span between opposite sides of second rigid frame 4. In particular it has also been found that the covering portion 5 can have significant effect on the air flow into the pocket filter bag, and as such can be used advantageously to cause dust particles to be deposited toward the bottom of the pockets of the bag, and consequently fill the pockets of the bag from the bottom up. This has considerable advantage with regard to the lifetime and effectiveness of the filter. In this regard it has been found that at least for one bag type, the optimal configuration of the covering member 5 has an arcuate leading surface 13, for reduced drag and smooth flow, leading smoothly into trailing surfaces 12 which direct the airflow into the pockets. It has been found that the trailing surfaces 12 are preferably formed having an included angle between the two surfaces of between 150 and 450, and in particular that an included angle of approximately 30' is effective in causing dust particles to collect predominantly at the bottom of the pockets.

Having regard to the material of construction of the pocket bag header, it is preferred that for long life and corrosion resistance, which is important in some environments, that the pocket filter bag header is constructed from stainless steel. This has considerable advantage in some industries, for example in the dairy industry, where strict 66- hygiene requirements are enforced. It can be seen from the foregoing description that the i 20 pocket bag header described is particularly easy to produce from for example sheet stainless steel, requiring only simple bending and welding to form the complete unit.

However, for a lower cost construction it is possible that the unit be constructed from -'treated mild steel, or hard plastic materials.

The pocket bag filter header has been described in particular with regard to a five 25 pocket filter bag with tall narrow pockets, however, it is envisaged that it also has has*: application to other filter bag configurations having more or less pockets or for example a plurality of rows of square pockets.

As can be seen from the above description, the ventilation filter of the present invention, and in particular the pocket filter bag header described, has particular advantages over prior art ventilation filters and pocket bag filter headers in that rather than being required to discard both the bag and header, the two normally being an integral unit, only the replacement of the pocket filter bag is required, and the pocket filter bag header may be continuously re-used. Furthermore, the system for securing the two halves of the pocket filter bag is simple and efficient in use, requiring very little time to separate the two frames for removal of the pocket filter bag. Furthermore, it can be seen that the covering members of the second rigid frame serve not only to protect the seams between adjacent pockets of the bag but also cause advantageous air flows into the bag pockets and cause dust to collect therefore in preferred areas of the pockets. Still further, it can be seen that the bag header can be made in a simple manner from materials such as stainless steel, which is of considerable advantage, particularly in such industries as the dairy industry.

S

I

O

Claims (17)

1. A pocket filter bag header comprising: a first rigid frame, havin asurround portion and at least one support member between points on saisurroun ortion, saiurr portion adapted to engage in use inside a filter housing, and said at least one support member adapted to be disposed at and under and to support the seam between adjacent pockets of a pocket filter bag, secorn mCmr e, a second rigid frame having a urround portion and at least one covering member secon ttAme- spanning between points on saidsurround portion, said at least one cover member adapted to be disposed at and over the seam between adjacent pockets of a pocket filter bag to in use hold the seams between adjacent pockets of a pocket filter bag between said support members and said cover members, and disengageable connecting means, connecting said surround portion of said first S 15 rigid frame against said surround portion of said second rigid frame.

2. A pocket filter bag header as claimed in claim 1 wherein at leat one surface of said surround portion of said first frame is adjacent at least one surface of said surround portion of said second frame, and said disengageable connecting means connects said adjacent surfaces. 20

3. A pocket filter bag header as claimed in either claim 1 or claim 2 wherein said disengageable connecting means comprise at least one depression and at least one protrusion formed complementary to said depression, on opposing said adjacent surfaces, said at least one protrusion engaging in said at least one depression to connect said surround portions of said first frame and said second frame.

4. A pocket filter bag header as claimed in any one of claims 1 to 3 wherein each said covering member has a cross-section including a sustmtialy arcuate leading surface and two substaftialy straight trailing surfaces, trailing from opposite edges of said leading surface.

A pocket filter bag header as claimed in claim 4 wherein said sbstaAt straight Q, trailing surfaces have an included angle of between 150 and 450 therebetween. -8-

6. A pocket filter bag header as claimed in any one of claims 1 to 5 wherein each said supporting member has an arcuate leading surface to support the seams between adjacent pockets of a pocket filter bag.

7, A pocket filter bag header as claimed in any one of claims 1 to 6 wherein said surround portion of said first frame has a vertical outside surface, and a horizontal surface extending inwardly from one edge of said vertical surface, and said surround portion of said second frame has a vertical outside surface and a horizontal surface extending inwardly from one edge of said vertical surface, and said vertical outside surfaces of said first frame and said second frame are overlapping and adjacent.

8. A pocket filter bag header as claimed in claim 7 wherein said overlapping vertical surfaces and said two horizontal surfaces fbrm a U-section surround member, said surround member fitting in a pocket bag filter holding frame.

9. A pocket filter bag header as claimed in either claim 7 or claim 8 wherein each said support member spans between points on said horizontal surface of said first rigid frame. 15

10. A pocket filter bag header as claimed in any one of claims 7 to 9 wherein each said covering member spans between points on said horizontal surface of said second rigid frame.

*11. A pocket filter bag header as claimed in any one of claims 7 to 10 wherein the ends of said at least one support member and said at least one covering member are disposed 20 inside said U-section.

12. A pocket filter bag header as claimed in any one of claims 1 to 11 wherein said header is constructed from stainless steel or treated mild steel or rigid plastic.

13. A ventilation filter including a pocket filter bag header according to any one of claims 1 to 12.

14. A ventilation filter as claimed in claim 13 wherein each said covering member is adapted to be curved over the seams between adjacent pockets of said pocket filter bag.

A ventilation filter as claimed in either claim 13 or claim 14 wherein each said covering member is formed to in use deflect air flow from a direction substantially perpendicular to said second frame, such that said air flow is directed to the bottoms of the pockets of said pocket filter bag. -9-

16. A pocket filter bag header substantially as herein described with reference to and as illustrated by the accompanying drawings.

17. A ventilation filter substantially as herein described with reference to and as illustrated by the accompanying drawings. 48 The -&tee features, and .af..sompounds disclosed herein or referred to or indicate e specification and/or claim rs 'i application, individually etively, and any and all combinations 0 o S: DATED this FIRST day of APRIL 1996 Filtercorp International Limited by DAVIES COLLISON CAVE n* A Patent Attorneys for the applicant(s) ee P ABSTRACT A pocket filter bag header has a first frame including a surround and a plurality of support members spanning between opposite sides of the surround, and a second frame including a surround and a plurality of covering members spanning between opposite sides of the surround. Elongate deformations on each of the first and second frames engage 't .secure the first and second frames n" re unit with the covering members over the supporting members. The opening face of, pocket filter bag is disposed between the first frame and the second frame with seams between adjacent pockets supported by the supporting members which are disposed between adjacent pockets. The covering members S' cover the leading edge of the seams between adjacent pockets and are formed to direct dust flow toward the base of the adjacent pockets. 00 a o **0 :a a a. I- I