Filtration systems

Abstract

A gas filtration system including an orificed barrier having a plurality of orifices through which gas can be forced, each orifice being sealed by a filter bag via which said air can pass and be filtered, each filter bag having a mouth opening biased to an open condition to force a mouth opening seal of the filter bag against a seat of the orifice by an underlying resiliently deflectable band that is deformable inwardly to facilitate the seating with yet allow removal of the filter bag from the barrier, each filter bag defining a passage but with an enclosed end region such that at least some solid matter can be filtered from the passing air and is contained inside the bag.

Claims

1. A gas filtration system for inlet air of a building ventilation system comprising: an orifice plate having a first side and a second side, the orifice plate being attached to a building ventilation system, wherein the orifice plate has a plurality of orifices through each of which a solid contaminant containing stream of gas to be filtered can pass from one body of gas at the first side of the orifice plate to a second body of gas at the second side of the orifice plate via a filter bag associated with each said orifice, each filter bag is flexible and comprises an enclosed end region and a flexible ring interface region having a central ring axis wherein the flexible ring interface region is able to seal with said orifice plate in the orifice and wherein each filter bag is annularly supported by a band in the flexible ring interface region and extends from the second side of the orifice plate, the band being resilient so as to be deformable inwardly towards the ring axis to facilitate insertion and removal of the filter bag from the orifice plate but with sufficient return bias to a more relaxed condition to hold the bag from separation with the orifice plate and seal therewith in a manner so that gas must pass through the filter bag to move from said one body of gas to said second body of gas, and wherein the gas filtration system is configured such that the pressure of gas of the one body of gas at the first side of the orifice plate is higher than the pressure of gas in the second body of gas at the second side of the orifice plate, wherein at least some of the solid contaminant filtered from the gas by the filter bags is trapped inside of the filter bags, and wherein the filter bags have gas entering and passing therethrough from the first body of gas to the second body of gas.

2. The gas filtration system as claimed in claim 1 wherein the orifice plate locally separates two bodies of gas that are in communication with each other only via each said filter bags.

3. The gas filtration system as claimed in claim 1 wherein each orifice and band of each associated filter bag form a female/male relationship.

4. The gas filtration system as claimed in claim 1 wherein said ring interface region comprises two axially spaced ribs between which the orifice plate locates for engagement to hold each of the filter bags from separation from the orifice plate.

5. The gas filtration system as claimed in claim 4 wherein the two ribs are parallel and concentric.

6. The gas filtration system as claimed in claim 4 wherein the two ribs are part of said band.

7. The gas filtration system as claimed in claim 4 wherein the band has a resilient cylindrical ring that underlies a profiled ring, wherein the profiled ring provides the ribs of the band.

8. The gas filtration system as claimed in claim 1 wherein each filter bag comprises of a flexible sock.

9. The gas filtration system as claimed in claim 1 wherein each filter bag comprises a filter bag body made from a mesh.

10. The gas filtration system as claimed in claim 1 wherein the filter bags are filter socks.

11. The gas filtration system as claimed in claim 1 wherein the filter bags extend into the second body of gas a distance that is greater than the diameter of the orifice at where the bag is secured.

12. The gas filtration system as claimed in claim 1 wherein the orifice plate holds all said filter bags.

13. The gas filtration system as claimed in claim 1 wherein only the orifice plate holds said filter bags.

14. The gas filtration system as claimed in claim 1 wherein the orifice plate is planar and said orifices are defined in plane.

15. The gas filtration system as claimed in claim 14 wherein the filter bags are elongate socks and their elongate direction extends in a direction parallel to normal of the orifice plate.

16. An air inlet filtration system for a building ventilation system comprising: an airflow baffle having a first side and a second side, the airflow baffle being attached to a building ventilation system, wherein the airflow baffle has a plurality of orifices through each of which a solid contaminant containing stream of air from an air inlet to be filtered can displace from a first body of air on the first side of the baffle to a second body of air on the second side of the baffle via a filter bag associated with each said orifice, each filter bag being elongate and having an enclosed end region and comprising a flexible ring interface region wherein the flexible interface region is able to seal with a seat of said orifice and wherein each filter bag is annularly supported by a band in the flexible ring interface region and extends from the second side of the baffle, the band being resilient so as to be deformable inwardly of the ring axis to facilitate insertion and removal of the filter bag from a respective said orifice but with sufficient return bias to a more relaxed condition to hold the bag from separation with the baffle and seal therewith in a manner so that air must pass through the filter bag to move from said one body of air to the second body of air, and wherein the air filtration system is configured such that the pressure of air of the first body of air on the first side of the baffle is higher than the pressure of air in the second body of air on the second side of the baffle, and wherein at least some solid contaminant filtered from the air is trapped inside the filter bags and wherein the filter bags have air entering and passing therethrough from the first body of air to the second body of air.

17. The air filtration system as claimed in claim 16 wherein the air filtration system is configured for use as part of positive air pressure building pressurisation system.

18. An air intake for a building, comprising: a plurality of filter bags each seated with a seat of an orifice of a multi orificed manifold connected to a ventilation system of the building, wherein the multi orificed manifold has a first side orientable towards an exterior of the building and a second side orientable towards an interior of the building, wherein each of the plurality of filter bags has a mouth opening propped open to force a seal of the filter bag against a respective seat by an underlying ring shaped resiliently deflectable band that is deformable inwardly towards the ring axis to facilitate the seating and removal of the filter bag from said respective seat, and each bag having an enclosed end region projecting from the second side of the multi orificed manifold such that at least some solid contaminant filtered from air entering the building from the exterior of the building and passing through the filter bags into the interior of the building is contained inside the filter bags.

19. A building that includes a room where atmosphere in the room is able to be brought into a negative pressure differential to ambient atmospheric conditions outside the building, the room including a wall between the outside and the inside of the room and at which an orifice plate is mounted having at a plurality of orifices through each of which a solid contaminant containing stream of air to be filtered from the outside can pass into the room as air intake via a filter bag associated with each said orifice, each filter bag comprising an enclosed end region defining an internal containment zone and a flexible ring interface mouth region having a central ring axis and able to seal with said orifice plate in the orifice, wherein each filter bag is annularly supported by a band, the band being resilient so as to be deformable inwardly towards the ring axis to facilitate insertion and removal of the filter bag from the orifice plate but with sufficient return bias to a more relaxed condition to hold the bag from separation with the orifice plate and seal therewith in a manner so that air must pass through the filter bag to move into the room and wherein at least some solid contaminant filtered from the air by the filter bags is trapped inside of the filter bags.

20. The building as claimed in claim 19 wherein an internal containment zone of each filter bag projects from said plate into or towards said room.

21. The building as claimed in claim 19 wherein each filter bag is inflated by said air passing through it.

22. The air inlet filtration system of claim 16 wherein each filter bag is flexible.

23. The air intake of claim 18 wherein each filter bag is flexible.

24. The building of claim 19 wherein each filter bag is flexible.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The preferred forms of the present invention will now be described with reference to the accompanying drawings in which

(2) FIG. 1 illustrates a filtration system,

(3) FIG. 2 is a cross sectional view of a filter bag located with a barrier of the filtration system of the present invention,

(4) FIG. 3 is an alternative perspective view of FIG. 1,

(5) FIG. 4 is a face on view of a barrier of the filtration system of the present invention,

(6) FIG. 5 is a perspective view of a filter bag,

(7) FIG. 6 is a plan view of the filter bag of FIG. 5,

(8) FIG. 7 is a front view of the filter bag of FIG. 5,

(9) FIG. 8 is a sectional view through section AA of FIG. 6,

(10) FIG. 9 is a close up view of region B of FIG. 8,

(11) FIG. 10 is a partially exploded view of the mouth region of the filter bag,

(12) FIG. 11 shows the mouth region of the filter bag in a deformed condition for the purposes of insertion and/or removal from the barrier,

(13) FIG. 12 is a side view of a filter bag of a slightly different configuration,

(14) FIG. 13 is a partial sectional view through the filter bag of FIG. 12, and

(15) FIG. 14 is a view illustrating a different form of barrier to the barrier of FIG. 1 with which a filter bag shown in part is engaged.

(16) FIG. 15 shows a building that includes a room, the room including a wall between the outside and the inside of the room and at which an orificed barrier is mounted having a filter bag associated with each said orifice,

DETAILED DESCRIPTION

(17) With reference to FIG. 1 there is shown part of a filtration system. The filtration system preferably includes a plurality of filter bags 1 that are engaged within a sealed manner to a baffle or barrier 2. The barrier is the interface two bodies of air for example internal 33 and external 34 of a building 30. Air 3 external of a building may be drawn into ducting 4 by for example a fan 5 to be driven towards the barrier 2. In other embodiments there may not be ducting upstream of the barrier, and air is instead sucked into the filtration system by a downstream blower or vacuum.

(18) The barrier 2 may for example include a barrier plate 6 that has at least one orifice and preferably a plurality of orifices 7. Each orifice is preferably of a circular cross section. Air (for example a stream of air containing solid contaminant to be filtered out by the filtration system) can pass through the barrier plate 6 only through each orifice 7. The barrier plate at its periphery may be mounted to a holed wall 31 of the building 30 or to some other structure in a sealed manner.

(19) Each filter bag as for example seen in FIGS. 5-9 comprises of a filter bag body 8 that is preferably made of a material suitable for filtration. Such a material may preferably be a mesh, but may be for example be a cloth, fabric, textile or other material suitable for ventilation. In preferred embodiments the material is suitable for a filtration application wherein the filtration is used for removing insects or other flying and/or airborne contaminants from air that is to be delivered into a building, in particular a building used for food processing.

(20) The mesh may be between 150 and 800 microns. Alternative grades of mesh or other kinds of materials are also envisaged to be useful for use as part of the present invention.

(21) Each filter bag 1 includes a mouth opening 9 via which air can pass into the filter bag body to then pass through the filter bag by virtue of a pressure differential between opposite sides of the barrier.

(22) Preferably at the mouth 9 the filter bag is constructed in a manner to allow for the mouth to be moved between a relaxed condition as shown in FIG. 5 and a deformed condition as shown in FIG. 11. In the deformed condition a resilient band or cuff region 10 of the filter bag will bias the mouth back to the relaxed condition of FIG. 5. Each orifice 7 and filter bag at its cuff region is dimensioned so that in the relaxed condition a seating of the band region 10 occurs with the seat 11 of the orifice 7 of the barrier 6 as shown in FIG. 2. The band 10 is preferably profiled to have two rib regions 12 and 13 annularly positioned and substantially parallel and concentric with each other about the mouth entrance axis XX. Between the ribs a valley 14 exists or may be established when engaged with the barrier with a seat of an orifice. In some embodiments the band may be retained within a fold back of the sleeve of the filter bag body, the fold back being secured by a sewn or welded seam, for example as shown in FIG. 9.

(23) The cuff region 10 may be of a flexible or pliable or deformable material so that when the filter bag is inserted into an orifice the resiliently biased cuff region moving back towards a relaxed state will result in a seal being established at the seat 11 of an orifice of the barrier as can be seen in for example FIG. 2.

(24) The seat of the orifice may also include a pliable material to facilitate such sealing or alternatively may be made of a hard non-deformable or deflectable material such as a metal such as steel. In the example where the barrier 2 comprises of a steel plate 6 with the plurality of orifices therethrough as shown in FIG. 4, it is preferred that no additional modification to each orifice is done and a seal is established merely by the contact between the cuff 10 and the seat 11 of an orifice 7 of the barrier plate 6.

(25) The filter bag body 8 is in the figures shown to be substantially cylindrical in shape however alternative configurations can be provided. By having a sufficient length L to the filter bag it will be appreciated that each filter bag has a surface area that is larger than the area of each of orifice. This will facilitate airflow through the barrier in particular when the filters start to block up as a result of them collecting insects and other air pollutants. Such larger surface area than the surface area of the orifice 7 will mean that filter bags will need to be replaced less frequently therefore resulting in less downtime of the filtration system. An increase in surface area may not just be established by virtue of lengthening the filter bags in direction L but may also occur by a ballooning out of the filter bag in a direction lateral to the direction L. As the filter bag body is flexible, and is supported only at the mouth region by coupling to the orifice plate, the bag may hang in a flaccid condition when there is no airflow passing through the orifice. However when there is airflow, this may cause the bag to inflate or balloon out to some extent.

(26) In some embodiments the length L of the body 8 is about 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700 mm, and useful ranges may be selected between any of these values (for example, about 100 to about 600, about 200 to about 450, about 200 to about 500, about 250 to about 450, about 250 to about 500, about 300 to about 400, about 300 to about 450, about 300 to about 500, about 300 to about 550).

(27) In some embodiments the diameter of the mouth 9 of the filter bag is about 100, 150, 200, 250, 300, 350, 400, 450, 500, 550 mm and useful ranges may be selected between any of these values (for example about 100 to about 550, or about 150 to about 500, or about 150 to about 350, or about 200 to about 300 mm).

(28) In some embodiments the ratio of the diameter of the mouth 9:length L of the body 8 is about 1:0.5, 1:0.75, 1:1, 1:1.25, 1:1.5, 1:1.75, 1:2, 1:2.25, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:4, 1:5, 1:6, 1:7 and useful ranges may be selected between any of these values (for example about 1:1 to about 1:4, about 1:1 to about 1:3, 1:1 to about 1:2, about 1:2 to about 1:3, about 1:2 to about 1:4, about 1:1.25 to about 1:1.7, about 1:1.25 to about 1:2.25) As a further example, FIG. 1 shows a ratio of the diameter of the mouth 9:length L of the body 8 as about 1:2.5. As a further example, FIG. 2 shows a ratio of the diameter of the mouth 9:length L of the body 8 as about 1:3. As a further example, FIGS. 3 and 4 show a ratio of the diameter of the mouth 9:length L of the body 8 as about 1:3. As a further example, FIG. 5 shows a ratio of the diameter of the mouth 9:length L of the body 8 as about 1:1. A preferred method of inter-engaging is as shown with reference to FIGS. 10 and 11. Here you will see there is a flexible ring 10 reliant upon the deformability and resilience of the snap ring or band 22. Upon release from the condition as shown in FIG. 11 a firm inter-engagement as shown in FIG. 2 will result. To remove the flexible ring from the inter-engagement as shown in FIG. 2 there is a similar distortion required to enable its ready removal.

(29) In preferred forms of the present invention a suitable plastics material can be used for the band 22. It is shape retaining but can be resilient so that it can conform to the deformation required.

(30) Many different materials single or multiple can be used for the flexible seal. One choice for the flexible sleeve proper is SEEFLEX sleeve material which a plastics material having little resilience but being flexible.

(31) The sleeve can be formed from a film material, from fibres (e.g. of a non-woven material or a woven material), or some combination of them both e.g. a hybrid. Fibre examples include polyester, nylon, KEVLAR, PTFE, polyurethane, TEFLON, aramid, PP, etc.

(32) Depending on usage preferably the inner surface of the flexible sleeve is to a food grade.

(33) Alternative materials to any of those described can be used. There is no need for the material of the flexible bag to be homogeneous, i.e. it can have localised regions of different properties (e.g. material, rigidity, etc) if that is desirable in a particular application.

(34) Whilst there has been description of a particular profiling of the end of each of the bags in question, other profiled end forms are within the scope of the invention that provide for appropriate retention. These may include one or more annular rib. One rib and a correspondingly profiled seat is shown in FIGS. 12 to 14. The seat may include one or more channels 19. It is preferred that the profiling be of an annular nature rather than helical or otherwise.

(35) It is believed that the present invention provides industry with a useful alternative to existing apparatus and methodologies.

(36) FIGS. 12 through 14 as described show a single annular rib 26 at the mouth opening of the filter bag to be received by a complementary profile of the seat of the orifice, here formed as a spigot 25 as part of the baffle or barrier. The rib is analogously made to the twin rib form already described.