CA2169471C - Mist collector cartridge - Google Patents

Mist collector cartridge Download PDF

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Publication number
CA2169471C
CA2169471C CA002169471A CA2169471A CA2169471C CA 2169471 C CA2169471 C CA 2169471C CA 002169471 A CA002169471 A CA 002169471A CA 2169471 A CA2169471 A CA 2169471A CA 2169471 C CA2169471 C CA 2169471C
Authority
CA
Canada
Prior art keywords
filter
end cap
wrap
perforated
outer liner
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.)
Expired - Fee Related
Application number
CA002169471A
Other languages
French (fr)
Other versions
CA2169471A1 (en
Inventor
Joseph C. Tokar
Mervin E. Wright
Timothy H. Grafe
James A. Leblanc
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.)
Donaldson Co Inc
Original Assignee
Donaldson Co Inc
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
Priority claimed from US08/107,967 external-priority patent/US5415676A/en
Application filed by Donaldson Co Inc filed Critical Donaldson Co Inc
Publication of CA2169471A1 publication Critical patent/CA2169471A1/en
Application granted granted Critical
Publication of CA2169471C publication Critical patent/CA2169471C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/52Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material
    • B01D46/521Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D39/00Filtering material for liquid or gaseous fluids
    • B01D39/14Other self-supporting filtering material ; Other filtering material
    • B01D39/16Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1607Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
    • B01D39/1623Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/0001Making filtering elements
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/0002Casings; Housings; Frame constructions
    • B01D46/0005Mounting of filtering elements within casings, housings or frames
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/0027Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions
    • B01D46/003Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions including coalescing means for the separation of liquid
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2411Filter cartridges
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/56Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition
    • B01D46/62Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition connected in series
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/88Replacing filter elements

Landscapes

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

Abstract

A mist collector cartridge for collecting airborne liquids, and more particularly, a filter media having vertically oriented interconnected pleats treated with a low surface energy material to facilitate agglomeration and drainage of liquid which accumulates on the inner and outer surface of the filter media.

Description

W~ 9/05234 PC'TlI1S94109242 IS~° CO C R I
FIELD OF THE INVENTION
The p~°es~nt app~.~.c~ti~n relates t~ ~ a.st HACRGR0UrID OF THE IPT~IENTI0I3 ~~ 9/05234 ~~ ~ N I~(C~'/~JS~~1/092~2 A sysge~a~.dely g~ apse f~r per~s~1 ~~t c~~11~~~~~~

in some of the oil being forced through the bags, contaminating the downstream air.
Consequently, these filters have a generally declining efficiency as the oil collects in the filter.
As a result of the declining efficiency, the pressure drop across the Filter does not increase, makir_g it difficult to determine when the filter needs to be replaced. Disposal of such filters is also difficult because of environmental concerns over their oil content.
SL'?~MARY CF T'_~E I?~iE~T'_'CIV
The present filter system collects airbcrr_e liquids in a filter media having vertical pleats wit:n a separation therebetween. The separation between the vertical pleats is maintained by a pleat spacing arrangement. The filter media is treated with a low surface energy material so that liquids contacting the inner or outer surface of the media agglomerate and drair_ downward along the vertical pleats.
The low surface energy coating is preferably an aliphatic fluorocarbon.
Liquid which accumulates on the inner surface of the filter media drains downward into a bottom cover where it is diverted away from the downstream air.
The filter media prevents airborne lic_ruid from entering the downstream air. Consequently the r~E~
_ ~~E~9~~

filter media has a predictable change in pressure across the filter media over time. The predictable nature of the change in pressure across the filter media allows for predictive maintenance of the filter cartridge.
S The filter cartridge may include a pre-filter wrap extending around the outer surface of the filter cartridge to cause the formation of larger droplets of the airborne liquid or_ the pre-filter wrap. These larger droplets more easily drain off of the filter cartridge.
0 A variety of pre-filter wraps are contemplated, including high loft air-laid or dry-laid materials, fully open cellu~~.a= f~.ltra~ion foams, and fiber glass wool products.
The filter cartridge retenticr_ system relates tc a 15 mechanism for releasably retaining a filter cartridge w=thin a filtration system between an operational position and a released position.
A support member is pivotally attached at one end within the filtration system for supporting the filter 20 cartridge. End stops are provided on the support member for retaining the filter cartridge in proper aligr_ment with an exhaust port in the filtration system. A handle is pivotally attached to the free end of the support member so that the support member can be moved between a generally 25 horizontal operational position for engaging the filter ~Ir~E~~~~~

~~ 9510523 ~ ; } l~c~~'/t~ls~~I/09~~s~
Figure 2 is ~ perspective view ~f ~ pr~f~r~°~~
filter cartridge retenti~n mechanism in the ~perat,a~nal p~siti~n~
Fagure 3 as a perspective view ~f a preferred falter cartridge retenti~n echanasm an tae reclaned aid released p~sati~ng Fi re ~ is a perspective view ~f ~ne a ~diment ~f the mist c~llect~r cartridge wath a multiple layer pre~
falter wrapo ~.0 Figure 5 is a t~p vaew ~f the mist c~llect~r cartridge ~f Figure 4;
Fgg~xre 6 as a sects~aaal vaew ~f ghe pgeferred ~aast c~llect~r cartridge sang multiple layers ~f n~n~~~ve~a aar~
laid material as a pre~filter wrap~ and Fi re 7 is a fl~w chart ill~astrata~g the meth~d ~f manufacturing the preferred. mast c~llect~r cartradgeo DETAIIaED DESCRIPTI~N ~F TFiE PREFERRED F.RM3~I~T~E
Figaare 1 illustrates a mist c~llecta~n system 1~
~0 fcr use with the preferred mist ccllectcr cartrade~e loo ~t preferred falter cartridge retenta~n mechanasm 14 and ~aast c~llect~r cartridge 12 nay be used in any suatahle ~'~ 95/0523 ~~ ~ r; I~fC~'/13T~~~I0~2~~
retaaned ~n the ~~~er ch e~ 20 ~f the ~.~st ~~~2.~c~:~~~a PC'TILT~94/09242 ~V~ 95105234 horizontal position, the support members are angled downward toward ~4 to allow easy the door insertion or removal of a mist collector The handle cartridge 62 ~.2~

operates as an extension 68 of the support members 56 to 20 facilitate insertion and removal of a mist collector W~ 95105234 ~ P~'~'11E11S94109242 The pre-filter wrap 91 may be constructed of a foamed urethane material, also referred to as a fully open cellular filtration foam. A foam material suitable for this purpose is available under the trade n a Filter Fo from Scott Foam Inc., Chester, P~.. The outer wrap 92 is approximately 100 pores/inch. In operation, the foamed urethane wrap 91 holds liquid, but does not build resistance to air flow.
Figure 6 illustrates a sectional view of the preferred mist collector cartridge 12' of the present invention. The bottom end cap 90 preferably has a sloped portion 100 which allows oil that is collected on the inner surface 102 of cartridge 12~ to drain through filter media 104 and into the hopper 40.
The filter media 104 preferably comprises a synthetic glass and polyester material arranged to fo a cylindrical pleated filter cartridge. The filter media 104 preferably has a high efficiency, between 70 and 90 percent at .778 micron particles.
To keep pleats 107 correctly spaced, the filter media 104 is scored to create alternating rectilinear line portions 118 and curvilinear line portions 120. wring the corrugation process, dimples 109 are integrally formed in the filter media 104 along the pleat tips 106 to maintain the spacing between the pleats 107. Construction of a corrugated filter media of this type is disclosed in U.S.
Patent No. 4,452,619, issued to Wright et al. on June 5, 1984.
As will be discussed below, as dirt and oil accumulate on the filter media 104, the media 104 become partially clogged so that the air flowing through the filter media 104 accelerates to create additional pressure on the filter media 104. In order for the filter media 104 to withstand the increased pressure, the pleats 107 are preferably space more closely together than on an air filter, giving the filter media 104 additional structural integrity. Because pleats on an ordinary air filter are generally spaced further apart, they would probably collapse under the air pressure in the present mist collection system.
The filter media 104 is preferably a low surface energy synthetic fiber matrix constructed from fibers having a thickness of less than .030". The filter media 104 may be treated with a low surface energy material, such as an aliphatic fluorocarbon. One low energy coating suitable for this purpose is sold under the trade name Scotchguard~ or Scotchban~ Protector, by 3M Corporation, St. Paul, MN. Scotchban~ Protector is described in brochure entitled Introducing FX-845 Scotchban Chemistry Takes On A New Life, dated 1991. Low surface energy coatings and low surface energy materials create a low surface energy on the filter media 104 which facilitates agglomeration of the oil and promotes drainage. The pre-filter wraps 91, 110 may also be treated with a low surface energy material.
As is illustrated in Figure 6, the filter media 104 is preferably recessed or set back from the inside surface of the outer liner 88 so that a space 89 is formed between the outer liner 88 and the filter media 104. The space 89 allows most of the oil that penetrates the pre-filter wrap 91 to form droplets on the inside surface of the pre-filter wrap 91 or the outer liner 88, rather than on the filter media 104.
The pleats 106 are arranged vertically in the cartridges 12, 12'. The filter media 104, and inner and outer liners 86, 88 are retained in the top and bottom end caps 82, 90 by a filter media adhesive 108, such as plastisol. The hook portion 96' of a fastener material may be retained between the outer liner 88 and the top end cap 82 around the perimeter of the mist collector cartridge 12' by the adhesive 108. The pre-filter wrap 91 may then be attached directly to the mist collector cartridge 12, 12' Oil mist too fine to collect on the outside surface of the filter media 104 may emerge on the inner surface 102 of the pleats 106. The vertical pleats 106 allow liquid collected on the inner surface 102 to drain downward onto the bottom end cap 90 of the cartridges 12,12', where it passes through the filter media 104 and into the hopper 40.
The filter media 104 is preferably constructed according the flow chart illustrated in Figure 7. The flat filter paper stock is preferably dipped in a low surface energy coating material 130, such as an aliphatic fluorocarbon. It should be understood that the paper stock may be treated or wetted by a variety of methods, including spraying. The excess coating material is removed by compressing the coated paper stock between a pair of compression rollers 132. The coated paper stock is then dried in a convection drying oven 134.
Prior to pleating, the paper stock is corrugated 136 by pressing a series of grooves lengthwise along the paper with a heated roller. The paper stock is then pleated 138 to form the filter media 104 and inserted into a filter housing 140. The preferred corrugation process is disclosed in U.S. Patent No. 4,452,619, issued to Wright et al. It will be understood that the cylindrical filter cartridge illustrated herein is set forth by way of example only and that a variety of filter configurations are possible. For example, generally planar filter cartridges having suitable drainage mechanism may be used in place of the cylindrical cartridge.
Figure 6 also illustrates the preferred pre-filter wrap 110 of the present invention. The pre-filter wrap 110 is preferably constructed of multiple layers of non-woven air-laid mediums, such as high loft air-laid or dry-laid materials. Because of the nature of the pre-filter wrap 110, it may be attached directly to the hook portion 96' without the use of the mating hook-portion.
In the preferred embodiment, the outer pre-filter layer 112 is approximately 0.75" of open material having a density of 6.7 ounces/sq.yd. and a solidity of 0.8%. A
product meeting these specifications is sold under the trade name Airlaid Media by Comulus Fiber Corp. located in Charlotte, NC. The two inner layers 114,116 are approximately 0.25" of a high efficiency material having a density of 3.62 ounces/sq.yd. and a solidity of 1.60. A

product meeting these specifications is available from Chemwove Corp. in Charlotte, NC.
The preferred pre-filter wrap 110 accumulates oil 25 during operation of the mist collection system 10. As oil accumulates, the pressure drop across the filters 12,12' not absorb the oil, but instead separates it and drains it off so that it can be collected and disposed of apart from the filter 12. In some applicaticns, it is pcssible to recycle the collected fluid.
Further, because the filter media 104 is pleated, it has a large surface area which allows air flowing through the media 104 to move at a low velocity, reducing the tendency of oil to be blown off the inner surface 102 of the filter 12 into the downstream air.
In the preferred embodiment, the efficiency and pressure drop across the cartridges 12, 12' increase cver i , r"" cartrir'ga 12, 12' fvinction ~Or a ti me . _he m_st coi~.ect~,L ..
long period of time because the media 104 does net become sa~.urated with oil. As the filters 12, ,~.2' become clogged with dirt and other particulates, and t:2e pressure drcp across the filters 12, 12' increases. Therefore, t:~e pressure drop across the filter 12, 12' corresponds to the amount of useful life remaining in the filters 12, 12', which can be used to indicate when the filters 12, 12' need to be replaced.
It will be understood by those skilled in the art that the present inventions are not limited to the examples discussed above, but may be changed or modified without departing from the spirit or scope of the invention. For example, a wide variety of filter cartridge configurations may be used in cembinaticn with a variety of drainage A,~~,~r.~ ~T
w ~ <u:_'~ ~~t

Claims (22)

What is claimed is:
1. A cylindrical filter cartridge comprising:
(a) a first end cap having a central opening and a gasket circumscribing said central opening;
(b) a second end cap, said second end cap being closed;
(c) an extension of pleated filter media extending from said first end cap to said second end cap;
(d) a perforated outer liner extending between said first end cap and said second end cap;
(e) a perforated inner liner extending between said first end cap and said second end cap; said pleated filter media being between the perforated inner liner and the perforated outer liner; and (f) a multi-layer filter pre-wrap covering the perforated outer liner, said multi-layer filter pre-wrap being removable and replaceable over said perforated outer liner.
2. The filter cartridge of claim 1, comprising a hook and loop fastening system for retaining said multi-layer filter pre-wrap around the perforated outer liner.
3. The filter cartridge of any one of claims 1 and 2, wherein said second end cap has a sloped portion.
4. The filter cartridge of any one of claims 1 to 3, wherein said the multi-layer filter pre-wrap comprises an outer wrap and an inner wrap, said outer wrap being more porous that said inner wrap.
5. The filter cartridge of any one of claims 1 to 4, wherein the pleated filter media includes dimples to maintain a spacing between pleats.
6. The filter cartridge of any one of claims 1 to 5, wherein the filter media is set back from the perforated outer liner.
7. The filter cartridge of any one of claims 1 to 6, comprising an aliphatic fluorocarbon material on the filter media.
8. A cylindrical filter cartridge comprising:
(a) a first end cap having a central opening and a gasket circumscribing the central opening;
(b) a second closed end cap having a sloped portion;
(c) an extension of pleated filter media extending from the first end cap to the second end cap;
(d) a perforated outer liner extending between the first end cap and the second end cap, said perforated outer liner circumscribing the filter media; said pleated filter media being set back from said perforated outer liner;
(e) a perforated inner liner extending between the first end cap and the second end cap; said pleated filter media being between the perforated inner liner and the perforated outer liner;
(f) a multi-layer filter pre-wrap covering the perforated outer liner, said multi-layer filter pre-wrap being removable and replaceable over the perforated outer liner; said multi-layer filter pre-wrap including an outer wrap and an inner wrap; and (g) a hook and loop fastening system for retaining the multi-layer filter pre-wrap around the perforated outer liner.
9. The filter cartridge of claim 8, wherein the outer wrap of the multi-layer filter pre-wrap is more porous that the inner wrap.
10. The filter cartridge of any one of claims 8 and 9, wherein the pleated filter media includes dimples to maintain a spacing between pleats.
11. The filter cartridge of any one of claims 8 to 10, further comprising an aliphatic fluorocarbon material on the pleated filter media.
12. The filter cartridge of any one of claims 8 to 11, wherein the perforated inner liner and the perforated outer liner are metal.
13. A filter system for collecting an aerosol mist, comprising:
(a) a filter housing having an air inlet and an exhaust port; and (b) a filter cartridge, said filter cartridge being cylindrical and mounted in said housing having an open top connected to the exhaust port, the filter cartridge comprising:
(i) a first end cap having a central opening and a gasket circumscribing the central opening;
(ii) a second end cap, said second end cap being closed;

(iii) an extension of pleated filter media extending from the first end cap to the second end cap;
(iv) a perforated outer liner and a perforated inner liner, both extending between the first end cap and the second end cap; said pleated filter media being between the perforated outer liner and the perforated inner liner; and (v) a multi-layer filter pre-wrap covering the perforated outer liner, said multi-layer filter pre-wrap being removable and replaceable over the perforated outer liner;
(c) blower apparatus for drawing air carrying the aerosol mist from an outside atmosphere into the housing through the air inlet, outer sidewall, filter media, and inner sidewall and for exhausting the air through the exhaust port.
14. The filter system of claim 13, wherein the filter cartridge further comprises a fastening system for retaining the multi-layer filter pre-wrap around the perforated outer liner.
15. The filter system of claim 14, wherein the fastening system for retaining the multi-layer filter pre-wrap around the perforated outer liner is a hook and loop fastening system.
16. The filter system of claim 13, wherein the multi-layer filter pre-wrap of the filter cartridge comprises an outer wrap and an inner wrap, the outer wrap being more porous that the inner wrap.
17. The filter system of claim 13, wherein the second end cap has a sloped portion.
18. The filter system of claim 13, wherein the pleated filter media of the filter cartridge includes dimples to maintain a spacing between pleats.
19. The filter system of claim 13, wherein the filter media of the filter cartridge is set back from the perforated outer liner.
20. The filter system of claim 13, wherein the filter cartridge further comprises an aliphatic fluorocarbon material on the filter media.
21. A method of removing aerosol mist from an air stream, comprising the steps of:
(a) providing a mist collection system comprising:
(i) a filter housing having an air inlet and an exhaust port; and (ii) a filter cartridge, said filter cartridge being cylindrical and mounted in the housing, the filter cartridge comprising:
(A) a first end cap having a central opening;
(B) a second end cap, the second end cap being closed;
(C) an extension of pleated filter media extending from the first end cap to the second end cap;
(D) a perforated outer liner and a perforated inner liner; said pleated filter media being between the perforated inner liner and the perforated outer liner; and (E) a multi-layer filter pre-wrap covering the perforated outer liner, and being removable and replaceable over the perforated outer liner;
(b) passing air containing aerosol mist into the housing via the air inlet and to the filter cartridge, and passing the air through the multi-layer filter pre-wrap and then the filter media; and (c) obtaining cleaned air through the central opening in the first end cap.
22. The method of claim 21, further comprising the step of collecting liquid by draining a liquid from the multi-layer filter pre-wrap and the filter media.
CA002169471A 1993-08-16 1994-08-16 Mist collector cartridge Expired - Fee Related CA2169471C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US08/107,967 US5415676A (en) 1993-08-16 1993-08-16 Mist collector cartridge
US08/107,967 1993-08-16
PCT/US1994/009242 WO1995005234A1 (en) 1993-08-16 1994-08-16 Mist collector cartridge

Publications (2)

Publication Number Publication Date
CA2169471A1 CA2169471A1 (en) 1995-02-23
CA2169471C true CA2169471C (en) 2006-10-03

Family

ID=37101727

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002169471A Expired - Fee Related CA2169471C (en) 1993-08-16 1994-08-16 Mist collector cartridge

Country Status (1)

Country Link
CA (1) CA2169471C (en)

Also Published As

Publication number Publication date
CA2169471A1 (en) 1995-02-23

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