GB2539477A - Filter assembly - Google Patents

Filter assembly Download PDF

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Publication number
GB2539477A
GB2539477A GB1510674.3A GB201510674A GB2539477A GB 2539477 A GB2539477 A GB 2539477A GB 201510674 A GB201510674 A GB 201510674A GB 2539477 A GB2539477 A GB 2539477A
Authority
GB
United Kingdom
Prior art keywords
assembly
fume
filter
wall
filter medium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB1510674.3A
Other versions
GB201510674D0 (en
Inventor
Jason Bloomfield Richard
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bofa International Ltd
Original Assignee
Bofa International Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bofa International Ltd filed Critical Bofa International Ltd
Priority to GB1510674.3A priority Critical patent/GB2539477A/en
Publication of GB201510674D0 publication Critical patent/GB201510674D0/en
Publication of GB2539477A publication Critical patent/GB2539477A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D50/00—Combinations of methods or devices for separating particles from gases or vapours
    • B01D50/20—Combinations of devices covered by groups B01D45/00 and B01D46/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
    • B01D45/04—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by utilising inertia
    • B01D45/08—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by utilising inertia by impingement against baffle separators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/0039—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with flow guiding by feed or discharge devices
    • B01D46/0041—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with flow guiding by feed or discharge devices for feeding
    • B01D46/0045—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with flow guiding by feed or discharge devices for feeding by using vanes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/10—Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/52—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material
    • B01D46/521—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)

Abstract

A fume filter assembly (1) with an enclosure which comprises a contaminant collection chamber (2) and a fume inlet (12) into the chamber. A filter medium (3), preferably pleated is located in the enclosure above the contaminant collection chamber having a substantially curved guide structure and able to receive gas from the fume inlet. The substantially curved guide structure (Fig 4) may be a channel having a radially outer wall with a plurality of slots or apertures, a radially inner wall and a roof portion extending for at least part of an angular/arcuate extent of the walls. In use, the filter assembly (1) may be loaded into a fume extraction housing whereby an end portion of a fume standpipe is received in the fume inlet aperture (12), with a flange engaging with and being deflected by an outermost surface of the fume standpipe. A suction pump may be activated to draw contaminated air through the fume inlet and into the chamber (2). Large, heavy particles carried within the air may be retained in the chamber with only smaller, lighter particles being distributed to the filter medium, thus prolonging the life of the filter medium.

Description

FILTER ASSEMBLY
Technical Field
The present invention relates generally to filter assemblies.
Background
In many industries such as electronics fabrication, laser marking/cutting/ engraving, pharmaceuticals and soldering of electronic circuit boards, extraction systems are used to capture hazardous particulate and gaseous/vaporised matter generated by industrial processes.
In broad terms, fume extraction systems include an enclosure or extraction device linked together by a pipework to a filter and an extraction fan. Known fume extraction systems comprise multiple graded particulate filters and a gas filter (typically activated carbon based) which are housed in a single unit, together with an extraction pump. The extraction pump draws contaminated air into the unit, through the filters to remove the contaminants and outputs filtered air to the working area.
When saturated, the filters, and in particular the particulate filter, must be replaced. In environments where high rates of particulates are generated, the filters will need to be replaced more often.
Known filter assemblies include bag filters in which a standpipe (which carries fumes towards and into the filter assembly) seal is sewn into the fabric of the bag filter. Because the bag filter is made of flexible material, the standpipe end (which is received by the seal) can have a tendency to become detached, and so allowing particles in the fumes to bypass the bag filter and directly reach a subsequent downstream filter (such as a HEPA filter) and so prematurely block that filter.
Bag filters also suffer from the drawback that when an operator needs to replace the filter bag filters have a tendency to contract and puff, potentially exposing the operator to harmful contaminants.
Also, with known filters, so-called skinning of filter media can occur in which (sticky) contaminate tends to form a skin over the filter surface and so reduces the life of the filter.
Known filter assemblies can relatively quickly become blocked by virtue of large particulate being retained in the filter and so significantly reducing the overall effective surface area.
We have realised that it would be desirable for there to be an improved filter 10 assembly.
Summary
According to the invention there is provided a fume filter assembly comprising an enclosure which comprises a contaminant collection chamber, a fume inlet into said chamber, and a filter medium located in said enclosure located above the contaminant collection chamber, and wherein, the contaminant collection chamber comprises a substantially curved guide to receive gas from the fume inlet.
The filter medium may comprise a pleated filter medium and the filter forms a zig-zag profile comprising inclined flat portions connected at alternating upper and lower apexes.
The substantially curved guide may be a channel which may comprise two flanking walls. A roof portion may be provided above the (curved) space defined between the flanking walls for at least part of the angular/arcuate extent of the walls (when viewed in plan). The roof portion may extend for only part of the angular/arcuate extent of the walls.
The curved channel may comprise a radially outer wall and a radially inner wall. The radially outer wall may have a greater angular extent than the radially inner wall.
The radially outer wall may comprise a plurality of slots or apertures, spaced apart with respect to the angular extent of the wall. The total area of the slots/apertures may be a minor proportion of the surface area of the radially outer wall.
The curved channel comprises an outlet in communication with the filter medium.
The contaminant collection chamber may be termed, at least in part, a drop-out containment collection chamber wherein when a suction pump is deactivated from drawing fumes through the assembly, the smaller/lighter particles tend to fall from the filter into the collection chamber.
The filter medium may comprise a gas porous fabric or sheet material.
The chamber, or at least a proportion or region thereof, may present a larger surface area to the contaminants carried in the fumes as compared to the surface area of a conduit which carries the fumes into the chamber.
The fume inlet may be arranged to cause the fumes to enter directly into the collection chamber. The fume inlet may be provided in a wall of the enclosure located adjacent to, and at least in part defining, the chamber.
The (drop-out) collection chamber may at least in part be a void.
The filter medium may be in communication with the containment collection chamber.
The (drop-out) chamber may be situated in a lower part of the enclosure and the filter medium located in an upper part of the enclosure.
The fume inlet may be arranged to be detachably connectable to a fume conduit.
The inlet may direct fumes directly into the contaminant collection chamber.
The inlet may comprise a seal arranged to engage with an end portion of the fume 30 conduit.
The filter assembly may be a unit which is removably insertable into a fume extraction housing. The assembly may be manually removably insertable into the fume extraction housing.
The fume extraction housing may completely accommodate the filter assembly.
The filter assembly may be slidable into and out of the fume extraction housing.
The filter assembly may be such that, in use, larger/heavier particles tend to stay within the chamber, or fall to a floor of the chamber, whereas smaller/lighter particles tend to be drawn upwardly towards the filter.
The filter assembly comprise a fume outlet located above the filter medium. The fume outlet may be provided at an upper distal end of the enclosure.
The filter assembly may be of substantially parallelepiped form.
The filter assembly may comprise one or more features as described in the description and/or as shown in the Figures.
Brief description of the drawings
One embodiment of the invention will now be described, by way of example only, with reference to the following drawings in which: Figure I is a perspective view of a filter assembly, Figure 2 s a schematic perspective view of a contaminant containment chamber.
Figure 3 is a plan view of a curved channel structure of the filter assembly, Figure 4 is a perspective view of the curved channel structure, Figure 5 is a schematic perspective view of the filter assembly, Figure 6a is a plan view of a seal, and Figure 6b is section of the seal of Figure 6a on A-A.
Detailed description
Figure I shows a fume filter assembly 1 with a rigid enclosure which comprises a contaminant collection chamber 2 and a filter medium 3. As will be described below, the filter assembly comprises a cyclonic type structure which increases the longevity of the assembly, by the provision of a substantially curved guide forming a channel.
The filter medium 3 comprises a pleated filter which comprises a gas porous material which is formed into a pleated configuration. As seen end-on, the filter forms a substantially zigzag profile, comprising inclined flat portions connected at alternating upper and lower apexes. The filter being of pleated construction provides a substantial filtration surface area, and in particular in view of the volume which is the filter occupies.
The filter medium 3 is located above the (drop-out) collection chamber 2. The filter medium is held in place above the chamber 2.
The contaminant collection chamber 2 is located in the lowermost region of the assembly. In a wall portion 10 of the enclosure, which wall portion at least in part defines the chamber, there is provided an aperture 12. The aperture 12 is bounded by a seal 15, which is shown in Figures 6a and 6b. The seal 15 comprises a circumferential slot 16 which receives the wall portion 10. A radially innermost part of the seal comprises a flange 17. As will be described below, the flange 17 is arranged to engage with a fume conduit (such as a standpipe). The aperture 12 is positioned immediately adjacent of the chamber 2 so that fumes are directed directly into the chamber. The seal 15 may be viewed as a grommet-style gasket.
An outlet 20 is provided at an upper end of the filter assembly and is directly above the filter 3. The outlet may comprise a mesh material.
As shown in Figure 2, a curved channel structure 20 is provided in the containment chamber 2. The curved channel structure may be fabricated from steel, and may be termed a scroll. The structure comprises two flanking walls, a radially inner wall 21 and a radially outer wall 22. Each of the walls is fixedly secured to a floor of the chamber 2, by way of brackets or flanged portions, with suitable fasteners. The curved channel structure is an integral part of the filter assembly.
The curvature circumscribed by each of the walls is achieved in this example by way of a series of flat portions arranged in a substantially arcuate shape. The angular, or arcuate, extent of the radially outer wall 22 is greater than that of the radially inner wall 21. The extent of the radially outer wall 22 serves to maximise (large) particulate collection effect (as described below).
The radially outer wall 22 is provided with multiple slots 25, spaced with respect to the arcuate cxtcnt of the wall. Each of the slots 25 is arranged to be vertically orientated, and present a surface area which is inferior to that of that proportion of the wall surface area which does not have slots.
The curved channel structure 20 further comprises a roof portion 23. The roof portion 23 sits atop the radially inner wall 21 and the radially outer wall 22, and serves to provide an upper constraint of the channel space located between the flanking walls 21 and 22. The roof portion 23 extends only for a part of the cxtcnt of the channel, and extends from the initial portion of the channel at which gas is received through the fume inlet. The roof portion 23 may comprise a series of adjacent plates.
The filter assembly 1 is arranged to be removably insertable into a fume extraction housing (not illustrated). The housing may comprise a cabinet in which is provided a space to removably receive and accommodate the filter assembly 1. The housing comprises support components, arranged to support the filter assembly, and the supports may comprise rails (for example provided on opposing sidewalls of the housing). The supports are arranged to automatically guide the inlet into connection with a standpipe which is mounted in (the rear of) the housing. The housing is also arranged to receive at least a further filter assembly, such as a High-Efficiency Particulate Air (HEPA) filter unit 4, located downstream of the filter assembly 1. The housing comprises or is connectable to a suction pump which is operative to draw fumes through the housing and therefore through the filter assemblies.
In use, the filter assembly 1 is loaded into the fume extraction housing. In so doing an end portion of a fume standpipe is received in the aperture 12, with the flange 17 engaging with and being deflected by the outermost surface of the pipe. When the suction pump is activated, contaminated air is drawn through the fume conduit and directly into the chamber 2. The contaminants carried within the air experience a change in velocity as they enter the curved channel of the chamber to bring about the air following a curved path. The larger/heavier particles tend to be retained on the floor 8 of the chamber 2, whereas the smaller/lighter particles tend to be drawn upwardly towards the filter 3. Heavier particulates carried by the air are caused, by a centrifugal force, to move towards the outside of the curved path, where they impact on the radially outer wall 22. On contact, some of the heavier particles arc retained on the surface of the wall by way of coalescence or by falling to the floor of the chamber. The slots 25 assist in bringing about separation of the particulates from the airstream. it should also be noted that those (larger) particles which are carried through the slots by the air, will experience a sudden decrease in velocity on passing into a larger space. Accordingly, they will tend to fall to the floor of the collection chamber on the other side of the radially outer wall. This region of the collection chamber may be termed a drop-out (or low velocity) region shown as 30 in Figure 2. Maximising the extend of the radially outer wall 22 maximises this beneficial effect. The slots 25 also provide pathways for a proportion of the air (and entrained smaller particles) to be distributed upwardly to the filtration medium 3. The roof portion 23 assists in channelling and constraining the air in a curved path, at least in the initial stages of the air entering the chamber.
Initially, the passage of the air leaving the radially outer wall 22 will be directly towards the filter 3 above, this being the path of least resistance. As this region of the filter, immediately above the curved channel, becomes blocked with particulates, the air passing through the channel will follow a longer curved passage and thereby allow more particulates to be collected. The curved channel 20 advantageously provides, as an integral part of the filter assembly, an additional stage of filtration.
The smaller/lighter particulates are prevented from passing through the filter 3, thus protecting the downstream HEPA filter. Further advantageously, the larger/heavier particulates are prevented from reaching the filter 3. This means that a larger proportion of the larger/heavier particulates do not prematurely Hock the filter.
Moreover, when the suction pump is deactivated, the smaller/lighter particles tend to fall from filter 3 (under gravity) towards and into the chamber 2. These factors increase the life of the filter, and the frequency of the filter replacement is reduced, along with reducing the cost of ownership of the extracted/filtration system. Liquid droplets, which would also reduce the life of the filter,are also separated from the airstream so this also prolongs filter life.
Because the fume conduit is not attached to the fabric of the filter 3 there is significantly reduced risk of particulates bypassing the filter 3 and reaching the HEPA filter. Furthermore, during filter replacement, because the filter is provided within the rigid enclosure this eliminates the risk of the filter being caused to contract and puff and so prevents contaminant exposure to the operator.
The filter assembly 1 may be considered as a prefilter which protects the HEPA filter from larger particulates.
it will be appreciated that in another embodiment, one or both of the inner and outer walls may be of smooth curved shape, as opposed to a series of flat sections which collectively define a substantially curved shape.

Claims (17)

  1. CLAIMS1. A fume filter assembly comprising an enclosure which comprises a contaminant collection chamber, a fume inlet into said chamber, and a filter medium located in said enclosure located above the contaminant collection chamber and wherein the contaminant collection chamber comprises a substantially curved guide structure to receive gas from the fume inlet.
  2. 2. An assembly as claimed in claim I in which the curved guide structure comprises a channel including two flanking walls.
  3. 3. An assembly as claimed in claim I or claim 2 in which the substantially curved guide structure comprises a radially outer wall and a radially inner wall.
  4. 4. An assembly as claimed in claim 3 in which the radially outer wall has a greater angular extent than the radially inner wall.
  5. 5. An assembly as claimed in claim 3 in which the radially outer all comprises a plurality of apertures, spaced along the arcuate extent of the wall.
  6. 6. An assembly as claimed in claim 5 which is arranged to cause at least some of the particulate entrained in the airstream passing through an aperture to experience a decrease in velocity on passing into a space at an opposite side of the radially outer wall, and thereby to tend to fall downwards to a floor of said space.
  7. 7. An assembly as claimed in any preceding claim in which the substantially curved guide structure is provided with a roof portion which extends for only some of the angular extent of the channel.
  8. 8. An assembly as claimed in claim I in which the filter medium comprises a pleated filter medium.
  9. 9. An assembly as claimed in claim I in which the filter medium comprises a gas porous fabric or sheet material.
  10. 10. An assembly as claimed in any preceding claim in which the filter med urn is n communication with the chamber.
  11. 11. An assembly as claimed in any preceding claim in which the chamber is situated in a lower part of the enclosure and the filter medium located in an upper part of the enclosure.
  12. 12. An assembly as claimed in any preceding claim in which the fume inlet is arranged to be detachably connectable to a fume conduit.
  13. 13. An assembly as claimed in any preceding claim in which the filter assembly is a unit which is removably insertable into a fume extraction housing.
  14. 14. An assembly as claimed in any preceding claim in which the filter assembly is arranged to be slidable into and out of the fume extraction housing.
  15. 15. An assembly as claimed in any preceding claim which comprises a fume outlet located above the filter medium.
  16. 16. An assembly as claimed in any preceding claim which is of substantially parallelepiped form.
  17. 17. A filter assembly substantially as described with reference to the drawings.Amendments to the claims have been filed as follows:CLAIMS1. A fume filter assembly comprising an enclosure which comprises a contaminant collection chamber, a fume inlet into said chamber, and a filter medium located in said enclosure located above the contaminant collection chamber and wherein the contaminant collection chamber comprises a substantially curved guide structure to receive gas from the fume inlet, in which the substantially curved guide structure comprises a radially outer wall and a radially inner wall, and the radially outer wall has a greater angular extent than the radially inner wall, and the radially outer wall comprises a plurality of apertures, spaced along the arcuate extent of the wall.2. An assembly as claimed in claim I in which the curved guide structure comprises a channel including two flanking walls.3. An assembly as claimed in claim I which is arranged to cause at least some of the particulate entrained in the airstream passing through an aperture to experience a decrease in velocity on passing into a space at an opposite side of the radially outer CO wall, and thereby to tend to fall downwards to a floor of said space.N 20 4. An assembly as claimed in any preceding claim in which the substantially curved guide structure is provided with a roof portion which extends for only some of the angular extent of the channel.An assembly as claimed in claim 1 in which the filter medium comprises a pleated filter medium.6. An assembly as claimed in claim 1 in which the filter medium comprises a gas porous fabric or sheet material.7. An assembly as claimed in any preceding claim in which the filter medium is in communication with the chamber.8. An assembly as claimed in any preceding claim in which the chamber is situated in a lower part of the enclosure and the filter medium located in an upper part of the enclosure.9 An assembly as claimed in any preceding claim in which the fume inlet s arranged to be detachably connectable to a fume conduit.10. An assembly as claimed in any preceding claim in which the filter assembly is a unit which is removably insertable into a fume extraction housing.11. An assembly as claimed in any preceding claim in which the filter assembly is arranged to be slidable into and out of the fume extraction housing.12. An assembly as claimed in any preceding claim which comprises a fume outlet located above the filter medium.13. An assembly as claimed in any preceding claim which is of substantially parallelepiped form.14. A filter assembly substantially as described with reference to the drawings.CON
GB1510674.3A 2015-06-17 2015-06-17 Filter assembly Withdrawn GB2539477A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1510674.3A GB2539477A (en) 2015-06-17 2015-06-17 Filter assembly

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1510674.3A GB2539477A (en) 2015-06-17 2015-06-17 Filter assembly

Publications (2)

Publication Number Publication Date
GB201510674D0 GB201510674D0 (en) 2015-07-29
GB2539477A true GB2539477A (en) 2016-12-21

Family

ID=53784909

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1510674.3A Withdrawn GB2539477A (en) 2015-06-17 2015-06-17 Filter assembly

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB574128A (en) * 1942-01-17 1945-12-21 British Filters Ltd Improvements in and relating to air cleaners
WO2011031154A2 (en) * 2009-09-11 2011-03-17 Advanced Tail-End Oil Company N.V. Pre-separating vane diffuser and method for introducing a flow-mixture in a separator
EP2471588A1 (en) * 2011-01-04 2012-07-04 Mann + Hummel GmbH Filter device for separating liquids from gases

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB574128A (en) * 1942-01-17 1945-12-21 British Filters Ltd Improvements in and relating to air cleaners
WO2011031154A2 (en) * 2009-09-11 2011-03-17 Advanced Tail-End Oil Company N.V. Pre-separating vane diffuser and method for introducing a flow-mixture in a separator
EP2471588A1 (en) * 2011-01-04 2012-07-04 Mann + Hummel GmbH Filter device for separating liquids from gases

Also Published As

Publication number Publication date
GB201510674D0 (en) 2015-07-29

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