U.S. patent application number 12/537069 was filed with the patent office on 2010-02-11 for z-media having flute closures, methods and apparatus.
Invention is credited to BRADLEY ALLEN GROSS, TED ANTHONY MOE, BENNY KEVIN NELSON.
Application Number | 20100032365 12/537069 |
Document ID | / |
Family ID | 41172319 |
Filed Date | 2010-02-11 |
United States Patent
Application |
20100032365 |
Kind Code |
A1 |
MOE; TED ANTHONY ; et
al. |
February 11, 2010 |
Z-MEDIA HAVING FLUTE CLOSURES, METHODS AND APPARATUS
Abstract
A single facer media is provided according to the invention. The
single facer media includes a fluted sheet attached to a facing
sheet and having a first end and a second end so that when the
single facer media is formed into a media pack, the first end or
the second end forms a media pack first face, and the other of the
first end or the second end forms a media pack second face.
Adhesive is provided between the fluted sheet and the facing sheet
at the first end or the second end, and wherein the fluted sheet
and the facing sheet are pushed together and adhered together at
the location of the adhesive to provide a seal between the fluted
sheet and the facing sheet. At least 25% of the flutes of the
fluted sheet comprise at least one ridge extending along at least
50% of the flute length between adjacent peaks. Filtration media
packs, filter elements, and methods for forming a single facer
media are provided.
Inventors: |
MOE; TED ANTHONY;
(MINNEAPOLIS, MN) ; NELSON; BENNY KEVIN;
(BLOOMINGTON, MN) ; GROSS; BRADLEY ALLEN;
(NORTHFIELD, MN) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Family ID: |
41172319 |
Appl. No.: |
12/537069 |
Filed: |
August 6, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61188670 |
Aug 6, 2008 |
|
|
|
Current U.S.
Class: |
210/470 ;
156/250; 156/60; 210/488; 210/493.1; 428/116 |
Current CPC
Class: |
Y10T 156/1005 20150115;
Y10T 156/1052 20150115; Y10T 156/1002 20150115; B32B 37/1284
20130101; Y10T 156/10 20150115; Y10T 428/24149 20150115; B01D
46/525 20130101; B01D 29/016 20130101; Y10T 156/1062 20150115; Y10T
156/102 20150115; B32B 37/10 20130101; B01D 46/522 20130101; B01D
25/001 20130101 |
Class at
Publication: |
210/470 ; 156/60;
156/250; 210/493.1; 210/488; 428/116 |
International
Class: |
B01D 29/07 20060101
B01D029/07; B32B 37/00 20060101 B32B037/00; B32B 38/04 20060101
B32B038/04; B01D 39/14 20060101 B01D039/14; B01D 46/52 20060101
B01D046/52; B32B 3/12 20060101 B32B003/12 |
Claims
1. A single facer media comprising: (a) a fluted sheet attached to
a facing sheet and having a first end and a second end so that when
the single facer media is formed into a media pack, the first end
or the second end forms a media pack first face, and the other of
the first end or the second end forms a media pack second face; (b)
adhesive provided between the fluted sheet and the facing sheet at
the first end or the second end, and wherein the fluted sheet and
the facing sheet are pushed together and adhered together along the
adhesive to provide a seal between the fluted sheet and the facing
sheet; and (c) wherein at least 25% of the flutes of the fluted
sheet comprise at least one ridge extending along at least 50% of
the flute length between adjacent peaks.
2. A single facer media according to claim 1, wherein at least 25%
of the flutes in the fluted sheet comprise at least two ridges
extending along at least 50% of the flute length between adjacent
same side peaks.
3. A single facer media according to claim 1, wherein the fluted
sheet exhibits a flute width height ratio greater than 2.5.
4. A single facer media according to claim 1, wherein the fluted
sheet exhibits a flute width height ratio greater than 3.0.
5. A filtration media pack comprising the single facer media
according to claim 1, and constructed with an adhesive bead to form
the media pack having inlet flutes for receiving dirty fluid and
outlet flutes for discharging filtered fluid, and wherein the dirty
fluid passes through the fluted sheet or the facing sheet to
provide filtering thereof.
6. A filtration media pack according to claim 5 provided in a
coiled arrangement.
7. A filtration media pack according to claim 5 provided in a
stacked arrangement.
8. A filtration media pack according to claim 5, wherein the media
pack has a flute density greater than 35 flute/inch.sup.2.
9. A filtration media pack according to claim 5, wherein the media
pack has a flute density greater than 45 flute/inch.sup.2.
10. A filtration media pack according to claim 5, wherein the media
pack has a flute volume asymmetry greater than 30%.
11. A filtration media pack according to claim 5, wherein the media
pack has a flute volume asymmetry greater than 70%.
12. A filtration media pack according to claim 5, wherein the media
pack comprises tapered flutes.
13. A filtration media pack according to claim 12, wherein the
tapered flutes comprise a first end having a first cross-sectional
area and a second end having a second cross-sectional area, wherein
the first cross-sectional area and the second cross-sectional area
are different, and wherein the seal provided by pushing the fluted
sheet and the facing sheet together is at one of the first end or
the second end.
14. A filter element comprising a media pack and a seal around the
media pack for engaging a housing, the media pack comprising a
single facer media and an adhesive bead to form inlet flutes for
receiving dirty fluid and outlet flutes for discharging dirty
fluid, the single facer media comprising: (a) a fluted sheet
attached to a facing sheet and having a first end and a second end
so that when the single facer media is formed into a media pack,
the first end or the second end forms a media pack first face, and
the other of the first end or the second end forms a media pack
second face; (b) adhesive provided between the fluted sheet and the
facing sheet at the first end or the second end, and wherein the
fluted sheet and the facing sheet are pushed together and adhered
together along the adhesive to provide a seal between the fluted
sheet and the facing sheet; and (c) wherein at least 25% of the
flutes of the fluted sheet comprise at least one ridge extending
along at least 50% of the flute length between adjacent peaks.
15. A filter element according to claim 14, further comprising a
handle extending axially from the media pack.
16. A filter element according to claim 14, wherein the media pack
has a flute density greater than 35 flute/inch.sup.2.
17. A filter element according to claim 14, wherein the media pack
has a flute density greater than 50 flute/inch.sup.2.
18. A filter element according to claim 14, wherein the media pack
has a flute volume asymmetry greater than 30%.
19. A filter element according to claim 14, wherein the media pack
has a flute volume asymmetry greater than 70%.
20. A filter element according to claim 14, wherein the media pack
comprises tapered flutes.
21. A filter element according to claim 14, wherein the media pack
comprises non-tapered flutes.
22. A filter element according to claim 14, wherein the seal around
the media pack for engaging a housing comprises a radial seal.
23. A filter element according to claim 14, wherein the seal around
the media pack for engaging a housing comprises an axial pinch
seal.
24. A method for forming a single facer media comprising: (a)
adhering a fluted sheet to a facing sheet by application of
adhesive between the fluted sheet and the facing sheet; and (b)
pushing the fluted sheet toward the facing sheet at the location of
the adhesive to form an adhesive seal; wherein at least 25% of the
flutes of the fluted sheet comprise at least one ridge extending
along 50% of the flute length between adjacent peaks.
25. A method according to claim 24, wherein the step of pushing the
fluted sheet toward the facing sheet at the location of the
adhesive to form an adhesive seal comprises applying a series of
rolls to the fluted sheet and facing sheet, the series of rolls
comprising: (a) a creaser wheel constructed to push the fluted
sheet toward the facing sheet; (b) a crowning wheel having a
surface for engaging the fluted sheet and further pushing the
fluted sheet toward the facing sheet; and (c) a flattening wheel
having a surface constructed for flattening the fluted sheet
relative to the facing sheet to provide a relatively flat
surface.
26. A method according to claim 24, further comprising: (a)
slitting the fluted sheet and facing sheet at the location of the
adhesive seal to form a first single facer media and a second
single facer media, wherein the first single facer media and the
second single facer media both include a relatively flat edge that
is closed to the flow of unfiltered fluid therethrough.
27. A method according to claim 26, wherein the method provides a
consistent flute closure without a step of indenting the flute
prior to the step of pushing the fluted sheet toward the facing
sheet at the location of the adhesive to form an adhesive seal.
28. A method according to claim 24, wherein the adhesive is applied
as a continuous adhesive strip.
29. A method according to claim 24, wherein the adhesive is applied
as a discontinuous adhesive strip.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application includes the disclosure o60f U.S.
Provisional Application Ser. No. 61/188,670 that was filed with the
United States Patent and Trademark Office on Aug. 6, 2008. A
priority right is claimed to U.S. Provisional Application Ser. No.
61/188,670, to the extent appropriate. The complete disclosure of
U.S. Provisional Application Ser. No. 61/188,670 is incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to z-media having closed
flutes, wherein the z-media can be used to form filter elements for
filtering a fluid. The invention is additionally directed to
filtration media packs, filter elements, methods for closing flutes
of filtration media.
BACKGROUND
[0003] Fluid streams, such as air and liquid, carry contaminant
material therein. In many instances, it is desired to filter some
or all of the contaminant materials from the fluid stream. For
example, air flow streams to engines for motorized vehicles or for
power generation equipment, gas streams to gas turbine systems, and
air streams to various combustion furnaces, carry particulate
contaminants therein that should be filtered. Also liquid streams
in engine lube systems, hydraulic systems, coolant systems or fuel
systems, can carry contaminants that should be filtered. It is
preferred for such systems, that selected contaminant material be
removed from (or have its level reduced in) the fluid. A variety of
fluid filter (air or liquid filter) arrangements have been
developed for contaminant reduction. In general, however, continued
improvements are sought.
[0004] Z-media generally refers to a type of fluted filtering media
element where a fluid enters flutes on a first face of the media
element and exits from flutes at a second face of the media
element. In general, the faces on z-media are provided on opposite
ends of the media. The fluid enters through open flutes on one face
and exits through open flutes on the other face. At some point
between the first face and the second face, the fluid passes from
one flute to another flute to provide for filtration.
[0005] Early forms of z-media were often referred to as corrugated
media because the characterization of the media was adopted from
the corrugated box board industry. Corrugated box boards, however,
were generally designed for carrying a load. Accordingly, flute
designs can be modified away from the standards and sizes from the
corrugated box board industry to provide improved filtration media
performance.
[0006] Various disclosures have been provided for modifying the
form of the flutes in z-media. For example, U.S. Pat. No. 5,562,825
describes corrugation patterns which utilize somewhat semicircular
(in cross section) inlet flutes adjacent narrow V-shaped (with
curved sides) exit flutes are shown (see FIGS. 1 and 3, of U.S.
Pat. No. 5,562,825). In U.S. Pat. No. 5,049,326 to Matsumoto et
al., circular (in cross-section) or tubular flutes defined by one
sheet having half tubes attached to another sheet having half
tubes, with flat regions between the resulting parallel, straight,
flutes are shown. See FIG. 2 of U.S. Pat. No. 5,049,326. U.S. Pat.
No. 4,925,561 to Ishii et al. (FIG. 1) shows flutes folded to have
a rectangular cross section, in which the flutes taper along their
lengths. In WO 97/40918 (FIG. 1), flutes or parallel corrugations
which have a curved, wave patterns (from adjacent curved convex and
concave troughs) but which taper along their lengths (and thus are
not straight) are shown. Also, in WO 97/40918 flutes which have
curved wave patterns, but with different sized ridges and troughs,
are shown.
[0007] In the case of z-media, flute closure techniques are
desirable that provide a consistent and reliable flute closure. In
addition, in the case of the use of adhesive to provide a flute
closure, flute closure techniques that minimize or reduce the
amount of adhesive are desirable.
SUMMARY
[0008] A single facer media is provided. The single facer media
includes a fluted sheet attached to a facing sheet and having a
first end and a second end so that when the single facer media is
formed into a media pack, the first end or the second end forms a
media pack first face, and the other of the first end or the second
end forms a media pack second face. Adhesive is provided between
the fluted sheet and the facing sheet at the first end or the
second end, and wherein the fluted sheet and the facing sheet are
pushed together and adhered together along the adhesive to provide
a seal between the fluted sheet and the facing sheet. At least 25%
of the flutes of the fluted sheet comprise at least one ridge
extending along at least 50% of the flute length between adjacent
peaks.
[0009] A filtration media pack is provided. The filtration media
pack includes a single facer media constructed with an adhesive to
form the media pack having inlet flutes for receiving dirty fluid
and outlet flutes for discharging filtered fluid. The dirty fluid
passes through the fluted sheet or the facing sheet to provide
filtering thereof. The fluid may be a liquid fluid or a gaseous
fluid. Exemplary liquid fluids include those fluids found in engine
lube systems, hydraulic systems, coolant systems, and fuel systems.
Exemplary gaseous streams include air streams such as air streams
to engines for motorized vehicles or for power generation
equipment, air streams to gas turbine systems, and air streams to
various combustion furnaces.
[0010] A filter element is provided. The filter element includes a
media pack and a seal around the media pack for engaging a housing.
The seal around the media pack for engaging a housing can be a
radial seal. Also, the seal around the media pack for engaging a
housing can be an axial seal such as an axial pinch seal.
[0011] A method for forming a single facer media is provided. The
method includes steps of: (a) adhering a fluted sheet to a facing
sheet by application of adhesive between the fluted sheet and the
facing sheet; and (b) pushing the fluted sheet toward the facing
sheet at the location of the adhesive to form an adhesive seal;
wherein at least 25% of the flutes of the fluted sheet comprise at
least one ridge extending along 50% of the flute length between
adjacent peaks. The method can additionally include a step of
slitting the fluted sheet and the facing sheet at the location of
the adhesive seal to form a first single facer media and a second
single facer media, wherein the first single facer media and the
second single facer media both include a relatively flat edge that
is closed to the flow of unfiltered fluid therethrough.
Furthermore, the method can provide a consistent flute closure
without a step of indenting flutes of the fluted sheet prior to the
step of pushing the fluted sheet toward the facing sheet at the
location of the adhesive to form an adhesive seal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a fragmentary, schematic, perspective view of an
exemplary z-filtration media according to the prior art.
[0013] FIG. 2 is an enlarged schematic, cross-sectional view of a
portion of the prior art media depicted in FIG. 1.
[0014] FIG. 3 is a schematic view of various corrugated media
definitions.
[0015] FIGS. 4a-c are enlarged schematic, cross-sectional views of
a portion of media according to the present invention.
[0016] FIG. 5 is a photograph showing an end view of wound
filtration media according to FIG. 4a.
[0017] FIG. 6 is a photograph showing a perspective view of dust
loaded into the filtration media shown in FIG. 6 wherein a portion
of the fluted sheet is peeled back to reveal a dust cake.
[0018] FIG. 7 is a perspective view of a tapered fluted sheet of
the media according to FIG. 4b.
[0019] FIGS. 8a and 8b are sectional views of a tapered media
according to FIGS. 4b and 4c.
[0020] FIG. 9 is schematic depiction of a process for closing
flutes of z-media.
[0021] FIG. 10 is an end elevational view of the creaser wheel of
FIG. 9.
[0022] FIG. 11 is a side elevational view of the crowning wheel of
FIG. 9.
[0023] FIG. 12 is an enlarged end view of a portion of the crowning
wheel of FIG. 11.
[0024] FIG. 13 is a side elevational view of the flattening wheel
FIG. 9.
[0025] FIG. 14 is an enlarged end view of a portion of the
flattening wheel of FIG. 13.
[0026] FIG. 15 is a sectional view of an exemplary air cleaner that
can include a filter element containing the filtration media pack
according to the present invention.
[0027] FIG. 16 is a partial, sectional view of a filter element
containing a filtration media pack according to the present
invention.
[0028] FIG. 17 is a perspective view of a filter element containing
a filtration media pack according to the present invention.
[0029] FIG. 18 is a perspective view of a filter element containing
a filtration media pack according to the present invention.
[0030] FIG. 19 is a bottom, perspective view of the filter element
of FIG. 18.
[0031] FIG. 20 is a side view of the center board of the filter
element of FIGS. 22 and 23.
[0032] FIG. 21 is a partial, sectional view of a filter arrangement
containing a filtration media pack according to the present
invention.
[0033] FIG. 22 is a partial, sectional view of an air cleaner
having a filter element containing a filtration media pack
according to the present invention.
[0034] FIG. 23 is a perspective view of an exemplary filter element
containing a filtration media pack according to the present
invention.
[0035] FIG. 24 is a perspective view of an exemplary filter element
containing a filtration media pack according to the present
invention.
DETAILED DESCRIPTION
Fluted Filtration Media
[0036] Fluted filtration media can be used to provide fluid filter
constructions in a variety of manners. One well known manner is as
a z-filter construction. The terms "z-filter construction" or
"z-filter media" as used herein, is meant to refer to a filter
element construction in which individual ones of corrugated,
folded, pleated, or otherwise formed filter flutes are used to
define longitudinal filter flutes for fluid flow through the media;
the fluid flowing along the flutes between inlet and outlet flow
ends (or flow faces) of the filter element. Some examples of
z-filter media filter elements are provided in U.S. Pat. Nos.
5,820,646; 5,772,883; 5,902,364; 5,792,247; 5,895,574; 6,210,469;
6,190,432; 6,350,296; 6,179,890; 6,235,195; Des. 399,944; Des.
428,128; Des. 396,098; Des. 398,046; and, Des. 437,401; each of
these fifteen cited references being incorporated herein by
reference.
[0037] The fluid that can be filtered by the filtration media pack
includes gaseous substance and liquid substances. Exemplary gaseous
substances that can be filtered includes air. Exemplary liquid
substances that can be filtered include water, oil, fuel, and
hydraulic fluid. A preferred type of fluid to be filtered by the
filtration media pack includes air. In general, much of the
discussion is directed at filtering air. It should be understood,
however, that the filtration media pack can be used to filter other
gaseous substances and other liquid substances.
[0038] One type of z-filter media utilizes two media components
joined together to form the media construction. The two components
are: (1) a fluted (for example, corrugated) media sheet; and, (2) a
facing media sheet. The facing media sheet is typically
non-corrugated, however it can be corrugated, for example
perpendicularly to the flute direction as described in
International Publication No. WO 2005/077487, published Aug. 25,
2005, incorporated herein by reference. Alternatively, the facing
sheet can be a fluted (for example, corrugated) media sheet and the
flutes or corrugations may be aligned with or at angles to the
fluted media sheet. Although the facing media sheet can be fluted
or corrugated, it can be provided in a form that is not fluted or
corrugated. Such a form can include a flat sheet. When the facing
media sheet is not fluted, it can be referred to as a non-fluted
media sheet or as a non-fluted sheet.
[0039] The type of z-filter media that utilizes two media
components joined together to form the media construction wherein
the two components are a fluted media sheet and a facing media
sheet can be referred to as a "single facer media" or as a "single
faced media." In certain z-filter media arrangements, the single
facer media (the fluted media sheet and the facing media sheet),
together, can be used to define media having parallel inlet and
outlet flutes. In some instances, the fluted sheet and non-fluted
sheet are secured together and are then coiled to form a z-filter
media construction. Such arrangements are described, for example,
in U.S. Pat. No. 6,235,195 and U.S. Pat. No. 6,179,890, each of
which is incorporated herein by reference. In certain other
arrangements, some non-coiled sections of fluted media secured to
flat media, are stacked on one another, to create a filter
construction. An example of this is described in FIG. 11 of U.S.
Pat. No. 5,820,646, incorporated herein by reference. In general,
arrangements where the z-filter media is coiled can be referred to
as coiled arrangements, and arrangements where the z-filter media
is stacked can be referred to as stacked arrangements. Filter
elements can be provided having coiled arrangements or stacked
arrangements.
[0040] Typically, coiling of the fluted sheet/facing sheet
combination (e.g., the single facer media) around itself, to create
a coiled media pack, is conducted with the facing sheet directed
outwardly. Some techniques for coiling are described in
International Publication No. WO 2004/082795, published Sep. 30,
2004, incorporated herein by reference. The resulting coiled
arrangement generally has, as the outer surface of the media pack,
a portion of the facing sheet, as a result. If desired, the single
facer media can be coiled so that the fluted sheet forms the outer
surface of the media pack.
[0041] The term "corrugated" used herein to refer to structure in
media, is meant to refer to a flute structure resulting from
passing the media between two corrugation rollers, i.e., into a nip
or bite between two rollers, each of which has surface features
appropriate to cause a corrugation affect in the resulting media.
The term "corrugation" is not meant to refer to flutes that are
formed by techniques not involving passage of media into a bite
between corrugation rollers. However, the term "corrugated" is
meant to apply even if the media is further modified or deformed
after corrugation, for example by the folding techniques described
in PCT WO 04/007054, published Jan. 22, 2004, incorporated herein
by reference.
[0042] Corrugated media is a specific form of fluted media. Fluted
media is media which has individual flutes (for example, formed by
corrugating or folding or pleating) extending thereacross. Fluted
media can be prepared by any technique that provides the desired
flute shapes. While corrugating can be a useful technique for
forming flutes having a particular size. When it is desirable to
increase the height of the flutes (the height is the elevation
between peaks), corrugating techniques might not be practical and
it may be desirable to fold or pleat the media. In general,
pleating of media can be provided as a result of folding the media.
In general, forming flutes by pleating can be referred to as
micropleating. An exemplary technique for folding the media to
provide pleats includes scoring and using pressure to create the
fold.
[0043] Filter element or filter cartridge configurations utilizing
z-filter media are sometimes referred to as "straight through flow
configurations" or by variants thereof. In general, in this context
what is meant is that the serviceable filter elements generally
have an inlet flow end (or face) and an exit flow end (or face),
with flow entering and exiting the filter cartridge in generally
the same straight through direction. The term "straight through
flow configuration" disregards, for this definition, air flow that
passes out of the media pack through the outermost wrap of facing
media. In some instances, each of the inlet flow end and outlet
flow end can be generally flat or planar, with the two parallel to
one another. However, variations from this, for example non-planar
faces, are possible in some applications. Furthermore, the
characterization of an inlet flow face and an opposite exit flow
face is not a requirement that the inlet flow face and the outlet
flow face are parallel. The inlet flow face and the exit flow face
can, if desired, be provided as parallel to each other.
Alternatively, the inlet flow face and the outlet flow face can be
provided at an angle relative to each other so that the faces are
not parallel. In addition, non-planar faces can be considered
non-parallel faces.
[0044] A straight through flow configuration is, for example, in
contrast to cylindrical pleated filter cartridges of the type shown
in U.S. Pat. No. 6,039,778, in which the flow generally makes a
substantial turn as its passes through the serviceable cartridge.
That is, in a U.S. Pat. No. 6,039,778 filter, the flow enters the
cylindrical filter cartridge through a cylindrical side, and then
turns to exit through an end face in a forward-flow system. In a
reverse-flow system, the flow enters the serviceable cylindrical
cartridge through an end face and then turns to exit through a side
of the cylindrical filter cartridge. An example of such a
reverse-flow system is shown in U.S. Pat. No. 5,613,992.
[0045] The filter element or filter cartridge can be referred to as
a serviceable filter element or filter cartridge. The term
"serviceable" in this context is meant to refer to a media
containing filter cartridge that is periodically removed and
replaced from a corresponding air cleaner. An air cleaner that
includes a serviceable filter element or filter cartridge is
constructed to provide for the removal and replacement of the
filter element or filter cartridge. In general, the air cleaner can
include a housing and an access cover wherein the access cover
provides for the removal of a spent filter element and the
insertion of a new or cleaned (reconditioned) filter element.
[0046] The term "z-filter media construction" and variants thereof
as used herein, without more, is meant to refer to any or all of: a
single facer media containing a fluted media sheet and a facing
media sheet with appropriate closure to inhibit air flow from one
flow face to another without filtering passage through the filter
media; and/or, a single facer media that is coiled or stacked or
otherwise constructed or formed into a three dimensional network of
flutes; and/or, a filter construction including a single facer
media; and/or, a fluted media constructed or formed (e.g., by
folding or pleating) into a three dimensional network of flutes. In
general, it is desirable to provide an appropriate flute closure
arrangement to inhibit unfiltered air that flows in one side (or
face) of the media from flowing out the other side (or face) of the
media as part of the filtered air stream leaving the media. In many
arrangements, the z-filter media construction is configured for the
formation of a network of inlet and outlet flutes, inlet flutes
being open at a region adjacent an inlet face and being closed at a
region adjacent an outlet face; and, outlet flutes being closed
adjacent an inlet face and being open adjacent an outlet face.
However, alternative z-filter media arrangements are possible, see
for example U.S. 2006/0091084 A1, published May 4, 2006 to Baldwin
Filters, Inc. also comprising flutes extending between opposite
flow faces, with a seal arrangement to prevent flow of unfiltered
air through the media pack. In many z-filter constructions
according to the invention, adhesive or sealant can be used to
close the flutes and provide an appropriate seal arrangement to
inhibit unfiltered air from flowing from one side of the media to
the other side of the media. Plugs, folds of media, or a crushing
of the media can be used as techniques to provide closure of flutes
to inhibit the flow of unfiltered air from one side of the media
(face) to the other side of the media (face).
[0047] Referring to FIG. 1, an exemplary type of media 1 useable as
z-filter media is shown. Although the media 1 is representative of
prior art media, many of the terms relied upon for describing the
media 1 can also describe portions of the media according to the
invention. The media 1 is formed from a fluted (in the example
corrugated) sheet 3 and a facing sheet 4. In general, the fluted
corrugated sheet 3 is of a type generally characterized herein as
having a regular, curved, wave pattern of flutes or corrugations 7.
The term "wave pattern" in this context, is meant to refer to a
flute or corrugated pattern of alternating troughs 7b and hills 7a.
The term "regular" in this context is meant to refer to the fact
that the pairs of troughs and hills (7b, 7a) alternate with
generally the same repeating corrugation (or flute) shape and size.
(Also, typically in a regular configuration each trough 7b is
substantially an inverse of each hill 7a.) The term "regular" is
thus meant to indicate that the corrugation (or flute) pattern
comprises troughs and hills with each pair (comprising an adjacent
trough and hill) repeating, without substantial modification in
size and shape of the corrugations along at least 70% of the length
of the flutes. The term "substantial" in this context, refers to a
modification resulting from a change in the process or form used to
create the corrugated or fluted sheet, as opposed to minor
variations from the fact that the media sheet forming the fluted
sheet 3 is flexible. With respect to the characterization of a
repeating pattern, it is not meant that in any given filter
construction, an equal number of hills and troughs is necessarily
present. The media 1 could be terminated, for example, between a
pair comprising a hill and a trough, or partially along a pair
comprising a hill and a trough. (For example, in FIG. 1 the media 2
depicted in fragmentary has eight complete hills 7a and seven
complete troughs 7b.) Also, the opposite flute ends (ends of the
troughs and hills) may vary from one another. Such variations in
ends are disregarded in these definitions, unless specifically
stated. That is, variations in the ends of flutes are intended to
be covered by the above definitions.
[0048] In the context of fluted filtration media, and in particular
the exemplary media 1, the troughs 7b and hills 7a can be
characterized as peaks. That is, the highest point of the hills 7a
can be characterized as peaks and the lowest points of the troughs
7b can be characterized as peaks. The combination of the fluted
sheet 3 and the facing sheet 4 can be referred to as the single
facer media 5. The peaks formed at the troughs 7b can be referred
to as internal peaks because they face toward the facing sheet 3 of
the single facer media 5. The peaks formed at the hills 7a can be
characterized as external peaks because they face away from the
facing sheet 3 forming the single facer media 5. For the single
facer media 5, the fluted sheet 3 includes repeating internal peaks
at 7b that face toward the facing sheet 4, and repeating external
peaks at 7a that face away from the facing sheet 4.
[0049] The term "regular" when used to characterize a flute pattern
is not intended to characterize media that can be considered
"tapered." In general, a taper refers to a reduction or an increase
in the size of the flute along a length of the flute. In general,
filtration media that is tapered can exhibit a first set of flutes
that decrease in size from a first end of the media to a second end
of the media, and a second set of flutes that increase in size from
the first end of the media to the second end of the media. In
general, a tapered pattern is not considered a regular pattern. It
should be understood, however, that z-media can contain regions
that are considered regular and regions that are considered
non-regular along the flute length. For example, a first set of
flutes may be considered regular along a distance of the flute
length, such as, one quarter the distance to three quarters the
distance, and then for the remaining amount of the flute length can
be considered non-regular as a result of the presence of a taper.
Another possible flute configuration is to have a
tapered-regular-tapered arrangement where, for example, a flute
tapers from a first face to a pre-selected location, the flute then
can be considered regular until a second pre-determined location,
and then the flute tapers to the second face. Another alternative
arrangement can be provided as a regular-taper-regular arrangement,
or as a regular-taper arrangement. Various alternative arrangements
can be constructed as desired.
[0050] In the context of z-media, there are generally two types of
"asymmetry." One type of asymmetry is referred to as area
asymmetry, and the other type of asymmetry is referred to volume
asymmetry. In general, area asymmetry refers to an asymmetry in
flute cross-sectional area, and can be exhibited by tapered flutes.
For example, area asymmetry exists if a fluted area at one location
along the length of a flute is different from the fluted area at
another location along the length of the flute. Because tapered
flutes exhibit a decrease in size from a first location (e.g., end)
to a second location (e.g., end) of the media pack or an increase
in size from a first location (e.g., end) to a second location
(e.g., end) of the media pack, there is an area asymmetry. This
asymmetry (area asymmetry) is a type of asymmetry resulting from
tapering and, as a result, media having this type of asymmetry can
be referred to as non-regular. Another type of asymmetry can be
referred to as volumetric asymmetry and will be explained in more
detail. Volumetric asymmetry refers to a difference between a dirty
side volume and a clean side volume within the filter media pack.
Media exhibiting volume asymmetry can be characterized as regular
if the wave pattern is regular, and the media can be characterized
as non-regular if the wave pattern is non-regular.
[0051] Z-media can be provided where at least a portion of the
flutes are closed to the passage of unfiltered air by a technique
other than providing a plug of adhesive or sealant. For example,
the ends of flutes can be folded or crushed to provide a closure.
One technique for providing a regular and consistent fold pattern
for closing flutes can be referred to as darting. Darted flutes or
darting generally refers to the closure of a flute wherein the
closure occurs by folding the flute to create a regular fold
pattern to collapse the flutes toward the facing sheet to provide a
closure rather than by crushing. Darting generally implies a
systematic approach to closing the ends of flutes as a result of
folding portions of the flute so that the flute closures are
generally consistent and controlled. For example, U.S. Patent
Publication No. US 2006/0163150 A1 discloses flutes having a darted
configuration at the ends of the flutes. The darted configuration
can provide advantages including, for example, a reduction in the
amount of sealant needed to provide a seal, an increased security
in the effectiveness of the seal, and a desirable flow pattern over
the darted end of the flutes. Z-media can include flutes having
darted ends, and the entire disclosure of U.S. Patent Publication
No. US 2006/0163150 A1 is incorporated herein by reference. It
should be understood that the existence of darts at the ends of
flutes does not render the media non-regular.
[0052] In the context of the characterization of a "curved" wave
pattern, the term "curved" is meant to refer to a pattern that is
not the result of a folded or creased shape provided to the media,
but rather the apex of each hill 7a and the bottom of each trough
7b is formed along a radiused curve. Although alternatives are
possible, a typical radius for such z-filter media would be at
least 0.25 mm and typically would be not more than 3 mm. Media that
is not curved, by the above definition, can also be useable. For
example, it can be desirable to provide peaks having a radius that
is sufficiently sharp so that it is not considered "curved." In
general, if the radius is less than 0.25 mm, or less than 0.20 mm,
the ridge or bottom can be characterized as bent, folded, or
creased. In order to reduce masking, it can be desirable to provide
a peak with a knife edge. The ability to provide a knife edge at
the peak can be limited by the equipment used to form the media,
the media itself, and the conditions under which the media is
subjected. For example, it is desirable to not cut or tear the
media. Accordingly, using a knife edge to create the peak can be
undesirable if the knife edge causes a cut or tear in the media.
Furthermore, the media can be too light or too heavy to provide a
sufficiently non-curved peak without cutting or tearing.
Furthermore, the humidity of the air during processing can be
enhanced to help create a tighter radius when forming the peak.
[0053] An additional characteristic of the particular regular,
curved, wave pattern depicted in FIG. 1, for the corrugated sheet
3, is that at approximately a midpoint 30 between each trough 7b
and each adjacent hill 7a, along most of the length of the flutes
7, is located a transition region where the curvature inverts. For
example, viewing back side or face 3a, FIG. 1, trough 7b is a
concave region, and hill 7a is a convex region. Of course when
viewed toward front side or face 3b, trough 7b of side 3a forms a
hill; and, hill 7a of face 3a, forms a trough. In some instances,
region 30 can be a straight segment, instead of a point, with
curvature inverting at ends of the segment 30. When the region 30
is provided as a straight segment, the wave pattern depicted in
FIG. 1, for example, can be characterized as an "arc-straight-arc"
wave pattern because of the repeating pattern of curve at the hill
7a, straight segment at the region 30, and curve at the trough
7b.
[0054] A characteristic of the particular regular, curved, wave
pattern corrugated sheet 3 shown in FIG. 1, is that the individual
corrugations are generally straight. By "straight" in this context,
it is meant that through at least 50% and preferably at least 70%
(typically at least 80%) of the length between edges 8 and 9, the
hills 7a and troughs 7b do not change substantially in
cross-section. The term "straight" in reference to corrugation
pattern shown in FIG. 1, in part distinguishes the pattern from the
tapered flutes of corrugated media described in FIG. 1 of WO
97/40918 and PCT Publication WO 03/47722, published Jun. 12, 2003,
incorporated herein by reference. The tapered flutes of FIG. 1 of
WO 97/40918, for example, would be a curved wave pattern, but not a
"regular" pattern, or a pattern of straight flutes, as the terms
are used herein.
[0055] Referring to FIG. 1 and as referenced above, the media 2 has
first and second opposite edges 8 and 9. For the example shown,
when the media 2 is coiled and formed into a media pack, in general
edge 9 will form an inlet end for the media pack and edge 8 an
outlet end, although an opposite orientation is possible in some
applications.
[0056] In the example shown, adjacent edge 8 is provided sealant,
in this instance in the form of a sealant bead 10, sealing the
fluted sheet 3 and the facing sheet 4 together. Bead 10 will
sometimes be referred to as a "single facer" bead, since it is a
bead between the corrugated sheet 3 and the facing sheet 4, which
forms the single facer media 5. Sealant bead 10 seals closed
individual flutes 11 adjacent edge 8, to passage of air
therefrom.
[0057] In the example shown, at adjacent edge 9 is provided
sealant, in this instance in the form of a sealant bead 14. Sealant
bead 14 generally closes flutes 15 to passage of unfiltered fluid
therein, adjacent edge 9. Bead 14 would typically be applied as the
media 2 is coiled about itself, with the corrugated sheet 3
directed to the inside. Thus, bead 14 will form a seal between a
back side 17 of facing sheet 4, and side 18 of the fluted sheet 3.
The bead 14 will sometimes be referred to as a "winding bead" since
it is typically applied, as the strip 2 is coiled into a coiled
media pack. If the media 2 is cut in strips and stacked, instead of
coiled, bead 14 would be a "stacking bead."
[0058] Referring to FIG. 1, once the media 1 is incorporated into a
media pack, for example by coiling or stacking, it can be operated
as follows. First, air in the direction of arrows 12, would enter
open flutes 11 adjacent end 9. Due to the closure at end 8, by bead
10, the air would pass through the media shown by arrows 13. It
could then exit the media pack, by passage through open ends 15a of
the flutes 15, adjacent end 8 of the media pack. Of course
operation could be conducted with air flow in the opposite
direction.
[0059] In more general terms, a z-filter media pack can be
characterized as comprising fluted filter media secured to facing
filter media, and configured in a media pack of flutes extending
between first and second flow faces. A sealant or seal arrangement
is provided within the media pack, to ensure that air entering
flutes at a first upstream flow face or edge cannot exit the media
pack from a downstream flow face or edge, without filtering passage
through the media. Alternately stated, a z-filter media pack is
closed to passage of unfiltered air therethrough, between the inlet
flow face and the outlet flow face, typically by a sealant
arrangement or other arrangement. An additional alternative
characterization of this is that a first portion of the flutes are
closed or sealed to prevent unfiltered air from flowing into the
first portion of flutes, and a second portion of the flutes are
closed or sealed to prevent unfiltered air from flowing out of the
second portion of flutes so that air passing into one of the first
face or the second face of the media pack and out the other of the
first face or the second face of the media pack passes through
media to provide filtration of the air.
[0060] For the particular arrangement shown herein in FIG. 1, the
parallel corrugations 7a, 7b are generally straight completely
across the media, from edge 8 to edge 9. Straight flutes or
corrugations can be deformed or folded at selected locations,
especially at ends. Modifications at flute ends for closure are
generally disregarded in the above definitions of "regular,"
"curved," and "wave pattern."
[0061] In general, the filter media is a relatively flexible
material, typically a non-woven fibrous material (of cellulose
fibers, synthetic fibers or both) often including a resin therein,
sometimes treated with additional materials. Thus, it can be
conformed or configured into the various fluted, for example
corrugated, patterns, without unacceptable media damage. Also, it
can be readily coiled or otherwise configured for use, again
without unacceptable media damage. Of course, it must be of a
nature such that it will maintain the required fluted (for example
corrugated) configuration, during use.
[0062] In the corrugation or fluting process, an inelastic
deformation is caused to the media. This prevents the media from
returning to its original shape. However, once the tension is
released the flutes or corrugations will tend to spring back,
recovering only a portion of the stretch and bending that has
occurred. The facing sheet is sometimes tacked to the fluted sheet,
to inhibit this spring back in the fluted (or corrugated)
sheet.
[0063] Also, the media can contain a resin. During the corrugation
process, the media can be heated to above the glass transition
point of the resin. When the resin cools, it will help to maintain
the fluted shapes.
[0064] The media of the fluted sheet 3, facing sheet 4 or both, can
be provided with a fine fiber material on one or both sides
thereof, for example in accord with U.S. Pat. Nos. 6,955,775,
6,673,136, and 7,270,693, incorporated herein by reference. In
general, fine fiber can be referred to as polymer fine fiber
(microfiber and nanofiber) and can be provided on the media to
improve filtration performance. As a result of the presence of fine
fiber on the media, it may be possible or desirable to provide
media having a reduced weight or thickness while obtaining desired
filtration properties. Accordingly, the presence of fine fiber on
media can provide enhanced filtration properties, provide for the
use of thinner media, or both. Fiber characterized as fine fiber
can have a diameter of about 0.001 micron to about 10 microns,
about 0.005 micron to about 5 microns, or about 0.01 micron to
about 0.5 micron. Nanofiber refers to a fiber having a diameter of
less than 200 nanometer or 0.2 micron. Microfiber can refer to
fiber having a diameter larger than 0.2 micron, but not larger than
10 microns. Exemplary materials that can be used to form the fine
fibers include polyvinylidene chloride, polyvinyl alcohol polymers
and co-polymers comprising various nylons such as nylon 6, nylon
4,6, nylon 6,6, nylon 6,10, and co-polymers thereof, polyvinyl
chloride, PVDC, polystyrene, polyacrylonitrile, PMMA, PVDF,
polyamides, and mixtures thereof.
[0065] Still referring to FIG. 1, at 20 tack beads are shown
positioned between the fluted sheet 3 and facing sheet 4, securing
the two together. The tack beads 20 can be for example,
discontinuous lines of adhesive. The tack beads can also be points
in which the media sheets are welded together.
[0066] From the above, it will be apparent that the exemplary
fluted sheet 3 depicted is typically not secured continuously to
the facing sheet, along the troughs or hills where the two adjoin.
Thus, air can flow between adjacent inlet flutes, and alternately
between the adjacent outlet flutes, without passage through the
media. However, unfiltered air which has entered a flute through
the inlet flow face cannot exit from a flute through the outlet
flow face without passing through at least one sheet of media, with
filtering.
[0067] Attention is now directed to FIG. 2, in which a z-filter
media construction 40 utilizing a fluted (in this instance regular,
curved, wave pattern) sheet 43, and a non-corrugated flat, facing
sheet 44, is depicted. The distance D1, between points 50 and 51,
defines the extension of flat media 44 in region 52 underneath a
given flute 53. The points 50 and 51 are provided as the center
point of the internal peaks 46 and 48 of the fluted sheet 43. In
addition, the point 45 can be characterized as the center point of
the external peak 49 of the fluted sheet 43. The distance D1
defines the period length or interval of the media construction 40.
The length D2 defines the arcuate media length for the flute 53,
over the same distance D1, and is of course larger than D1 due to
the shape of the flute 53. For a typical regular shaped media used
in fluted filter applications according to the prior art, the ratio
of the lengths D2 to D1 is typically within a range of 1.2-2.0,
inclusive. An exemplary arrangement common for air filters has a
configuration in which D2 is about 1.25.times.D1 to about
1.35.times.D1. Such media has, for example, been used commercially
in Donaldson Powercore.TM. Z-filter arrangements having a regular,
curved, wave pattern. Herein the ratio D2/D1 will sometimes be
characterized as the flute/flat ratio or the media draw for the
media.
[0068] The flute height J is the distance from the facing sheet 44
to the highest point of the fluted sheet 43. Alternatively stated,
the flute height J is the difference in exterior elevation between
alternating peaks 57 and 58 of the fluted sheet 43. The flute
height J takes into account the thickness of the fluted sheet 43.
The peak 57 can be referred to as the internal peak (the peak
directed toward the facing sheet 44), and the peak 58 can be
referred to as the external peak (the peak directed away from the
facing sheet 44). Although the distances D1, D2, and J are applied
to the specific fluted media arrangement shown in FIG. 2, these
distances can be applied to other configurations of fluted media
where D1 refers to the period length of a flute or the distance of
flat media underneath a given flute, D2 refers to the length of
fluted media from lower peak to lower peak, and J refers to the
flute height.
[0069] Another measurement can be referred to as the cord length
(CL). The cord length refers to the straight line distance from the
center point 50 of the lower peak 57 and the center point 45 of the
upper peak 58. The thickness of the media and the decision where to
begin or end a particular distance measurement can affect the
distance value because the media thickness affects the distance
value. For example, the cord length (CL) can have different values
depending upon whether the distance is measured from the bottom of
the internal peak to the bottom of the external peak or whether it
is measured from the bottom of the internal peak to the top of the
external peak. This difference in distance is an example of how the
media thickness effects the distance measurement. In order to
minimize the effect of the thickness of the media, the measurement
for cord length is determined from a center point within the media.
The relationship between the cord length CL and the media length D2
can be characterized as a media-cord percentage. The media-cord
percentage can be determined according to the following
formula:
media - cord percentage = ( 1 / 2 D 2 - CL ) .times. 100 CL
##EQU00001##
[0070] In the corrugated cardboard industry, various standard
flutes have been defined. These include, for example, the standard
E flute, standard X flute, standard B flute, standard C flute, and
standard A flute. FIG. 3, attached, in combination with Table 1
below provides definitions of these flutes.
[0071] Donaldson Company, Inc., (DCI) the assignee of the present
disclosure, has used variations of the standard A and standard B
flutes, in a variety of z-filter arrangements. The DCI standard B
flute can have a media-cord percentage of about 3.6%. The DCI
standard A flute can have a media-cord percentage of about 6.3.
Various flutes are also defined in Table 1 and FIG. 3. FIG. 2 shows
a z-filter media construction 40 utilizing the standard B flute as
the fluted sheet 43.
TABLE-US-00001 TABLE 1 (Flute definitions for FIG. 3) DCI A Flute:
Flute/flat = 1.52:1; The Radii (R) are as follows: R1000 = .0675
inch (1.715 mm); R1001 = .0581 inch (1.476 mm); R1002 = .0575 inch
(1.461 mm); R1003 = .0681 inch (1.730 mm); DCI B Flute: Flute/flat
= 1.32:1; The Radii (R) are as follows: R1004 = .0600 inch (1.524
mm); R1005 = .0520 inch (1.321 mm); R1006 = .0500 inch (1.270 mm);
R1007 = .0620 inch (1.575 mm); Std. E Flute: Flute/flat = 1.24:1;
The Radii (R) are as follows: R1008 = .0200 inch (.508 mm); R1009 =
.0300 inch (.762 mm); R1010 = .0100 inch (.254 mm); R1011 = .0400
inch (1.016 mm); Std. X Flute: Flute/flat = 1.29:1; The Radii (R)
are as follows: R1012 = .0250 inch (.635 mm); R1013 = .0150 inch
(.381 mm); Std. B Flute: Flute/flat = 1.29:1; The Radii (R) are as
follows: R1014 = .0410 inch (1.041 mm); R1015 = .0310 inch (.7874
mm); R1016 = .0310 inch (.7874 mm); Std. C Flute: Flute/flat =
1.46:1; The Radii (R) are as follows: R1017 = .0720 inch (1.829
mm); R1018 = .0620 inch (1.575 mm); Std. A Flute: Flute/flat =
1.53:1; The Radii (R) are as follows: R1019 = .0720 inch (1.829
mm); R1020 = .0620 inch (1.575 mm).
[0072] In general, standard flute configurations from the
corrugated box industry have been used to define corrugation shapes
or approximate corrugation shapes for corrugated media. Improved
performance of filtration media can be achieved by providing a
flute configuration or structure that enhances filtration. In the
corrugated box board industry, the size of the flutes or the
geometry of the corrugation was selected to provide a structure
suited for handling a load. The flute geometry in the corrugated
box industry developed the standard A flute or B flute
configuration. While such flute configurations can be desirable for
handling a load, filtration performance can be enhanced by altering
the flute geometry. Techniques for improving filtration performance
include selecting geometries and configurations that improve
filtration performance in general, and that improve filtration
performance under selected filtration conditions. Exemplary flute
geometries and configurations that can be altered to improve
filtration performance include flute masking, flute shape, flute
width height ratio, and flute asymmetry. In view of the wide
selection of flute geometries and configurations, the filter
element can be configured with desired filter element geometries
and configurations in view of the various flute geometries and
configurations to improve filtration performance.
Masking
[0073] In the context of z-media, masking refers to the area of
proximity between the fluted sheet and the facing sheet where there
is a lack of substantial pressure difference resulting in a lack of
useful filtration media when the filtration media is in use. In
general, masked media is not useful for significantly enhancing the
filtration performance of filtration media. Accordingly, it is
desirable to reduce masking to thereby increase the amount of
filtration media available for filtration and thereby increase the
capacity of the filtration media, increase the throughput of the
filtration media, decrease the pressure drop of the filtration
media, or some or all of these.
[0074] In the case of a fluted sheet arranged in a pattern with
broad radii at the peaks as shown in FIG. 2, there exists a
relatively large area of filtration media proximate the contact
area of the fluted sheet and the facing sheets that is generally
not available for filtration. Masking can be reduced by decreasing
the radii of the peak or contact point between the fluted sheet and
the facing sheet (e.g., providing sharper contact points). Masking
generally takes into account the deflection of the media when it is
under pressure (e.g., during filtration). A relatively large radius
may result in more of the fluted media being deflected toward the
facing sheet and thereby increasing masking. By providing a sharper
peak or contact point (e.g., a smaller radius), masking can be
reduced.
[0075] Attempts have been made to reduce the radii of contact
between the fluted sheet and the facing sheet. For example, see
U.S. Pat. No. 6,953,124 to Winter et al. An example of reducing the
radii is shown in FIG. 4a where the fluted sheet 70 contacts the
facing sheets 72 and 73 at relatively sharp peaks or contact points
74 and 75 in the fluted sheet 70. A curved wave pattern such as the
curved wave pattern shown in FIG. 1 generally provides a fluted
sheet having a radius at the peaks of at least 0.25 mm and
typically not more than 3 mm. A relatively sharp peak or contact
point can be characterized as a peak having a radius of less than
0.25 mm. Preferably, the relatively sharp peak or contact peak
point can be provided having a radius of less than about 0.20 mm.
In addition, masking can be reduced by providing a peak having a
radius of less than about 0.15 mm, and preferably less than about
0.10 mm. The peak can be provided having no radius or essentially a
radius of about 0 mm. Exemplary techniques for providing fluted
media exhibiting relatively sharp peaks or contact points includes
coining, bending, folding, or creasing the fluted media in a manner
sufficient to provide a relatively sharp edge. It should be
understood that the ability to provide a sharp edge depends on a
number of factors including the composition of the media itself and
the processing equipment used for providing coining, bending,
folding, or creasing. In general, the ability to provide a
relatively sharp contact point depends on the weight of the media
and whether the media contains fibers that resist tearing or
cutting. In general, it is desirable to not cut the filtration
media during coining, bending, folding, or creasing. While it is
desirable to reduce the radius of the peak (internal peak or
external peak) to reduce masking, it is not necessary that all of
the peaks have a reduced radius to decrease masking. Reduced
masking, and enhanced filtration performance, can be achieved by
providing at least some of the peaks (e.g., at least about 20% of
the peaks) with a relatively sharp peak or contact point.
Furthermore, depending on the design of the media, the external
peaks can be provided with a reduced radius or the internal peaks
can be provided with a reduced radius, or both the external peaks
and the internal peaks can be provided with a reduced radius in
order to decrease masking.
Increasing the Surface Area of Media
[0076] Filtration performance can be enhanced by increasing the
amount of filtration media available for filtration. Reducing
masking can be considered a technique for increasing the surface
area of media available for filtration.
[0077] The configuration of the fluted media can be characterized
by the flute width height ratio. The flute width height ratio is
the ratio of the flute period length D1 to the flute height J. The
flute width height ratio can be expressed by the following
formula:
flute width height ratio = D 1 J ##EQU00002##
Measured distances such as flute period length D1 and the flute
height J can be characterized as average values for the filtration
media along the flute length excluding 20% of the flute length at
each end. The distances can be measured away from the ends of the
flutes. It is typically the ends of the flutes that have a sealant
or closure. The flute width height ratio calculated at a flute
closure would not necessarily represent the flute width height
ratio of the flute where the filtration is taking place.
Accordingly, the measure of flute width height ratio can be
provided as an average value over the flute length with the
exception of the last 20% of the flute length near the ends of the
flutes to remove the effects of flute closure when the flutes are
closed at or near the ends. For "regular" media, it is expected
that the flute period length D1 and the flute height J will be
relatively constant along the flute length. By relatively constant,
it is meant that the flute width height ratio can vary within about
10% over the length of the flute excluding the 20% length at each
end where flute closure designs may effect the width height ratio.
In addition, in the case of a "non-regular" media, such as, media
having tapered flutes, the flute width height ratio can vary or
remain about the same over the length of the flute. By adjusting
the flute shape away from a theoretical equilateral triangle shape,
the amount of media in a given volume available for filtration can
be increased. Accordingly, flutes having a flute width height ratio
of at least about 2.2, at least about 2.5, at least about 2.7, or
at least about 3.0 can provide an increased surface area of media
available for filtration. In addition, providing a flute design
having a width height ratio of less than about 0.45, less than
about 0.40, less than about 0.37, or less than about 0.33 can
provide increased media area available for filtration. In general,
a theoretical flute having a equilateral triangle shape represents
a flute width height ratio of about 1.6.
[0078] Another technique for increasing the amount of filtration
media available for filtration includes increasing the flute
density of the media pack. The flute density refers to the number
of flutes per cross-sectional area of filtration media in a
filtration media pack. The flute density depends on a number of
factors including the flute height J, the flute period D1, and the
media thickness T. The flute density can be characterized as a
media pack flute density or as a single facer media flute density.
The equation for calculating the media pack flute density (.rho.)
for a filter element is:
.rho. = number of channels ( open and closed ) 2 .times. z - media
pack cross sectional area ##EQU00003##
The flute density of a filter element can be calculated by counting
the number of channels including those channels that are open and
those channels that are closed in a cross sectional area of the
filter element, and dividing that by two times the cross sectional
area of the filter element at the location where the number of
channels was determined. In general, it is expected that the flute
density will remain relatively constant across the length of the
filter element from the inlet flow face to the outlet flow face, or
vice versa. It should be understood that the z-media cross
sectional are refers to the cross sectional area of the media
(wound or stacked) and not necessarily to the cross sectional area
of the filter element. The filter element may have a sheath or a
seal intended to engage a housing that would provide the filter
element with a cross-sectional area that is greater than the
cross-sectional area of the media. Furthermore, the cross-sectional
area of the media refers to the effective area. That is, if the
media is wound around a core or mandrel, the cross-sectional area
of the core or mandrel is not part of the z-media pack
cross-sectional area. Furthermore, the number of channels refers to
the number of channels in the effective area.
[0079] An alternative equation for the calculation of flute density
(.rho.) for a single facer media is:
.rho. = 1 ( J + T ) .times. D 1 ##EQU00004##
In the equation for flute density per single facer media, J is the
flute height, D1 is the flute period length, and T is the thickness
of the fluted sheet. This alternate equation can be referred to as
the equation for calculating the single facer media flute density.
The single facer media flute density is determined based upon the
configuration of the single facer media. In contrast, the media
pack flute density is determined based upon the assembled media
pack
[0080] Theoretically, the media pack flute density and the single
facer media flute density should provide similar results. However,
it is possible that the media pack may be configured in such a way
that the media pack flute density and the single facer media flute
density provide different results.
[0081] The standard B flute shown in FIGS. 2 and 3 and
characterized in Table 1 provides a coiled filtration media having
a flute density (media pack flute density and single facer media
flute density) of about 34 flute/inch.sup.2. The media pack formed
from standard B flute media can be characterized as having an
average flute density of about 34 flute/inch.sup.2. The flute
density (whether expressed as the media pack flute density or the
single facer media flute density) can be considered an average
flute density for the media pack unless stated otherwise. The flute
density, therefore, may be referred to at times as the flute
density and at other times as the average flute density. In
general, increasing the average flute density refers to providing a
media pack having a flute density greater than the flute density
for standard B flute media. For example, increased flute density
can refer to a media pack having a flute density greater than 35.0
flute/inch.sup.2. The media pack can be provided having a flute
density of greater than about 36 flute/inch.sup.2, greater than
about 38 flute/inch.sup.2, greater than about 40 flute/inch.sup.2,
greater than 45 flute/inch.sup.2, or greater than about 50
flute/inch.sup.2. The media pack can be provided having a decreased
flute density (compared with standard B media) to provide decreased
pressure drop or less resistance to flow therethrough. For example,
the media pack can be provided having a media pack flute density of
less than 34.0 flute/inch.sup.2, less than about 30
flute/inch.sup.2, or less than about 25 flute/inch.sup.2.
[0082] In general, providing media having increased flute density
has a tendency to increase the surface area of media within a
volume of the media and, therefore, has a tendency to increase the
loading capacity of the filtration media. Accordingly, increasing
the flute density of media can have the effect of enhancing the
loading capacity of the media. However, increasing the flute
density of media can have the effect of increasing the pressure
drop through the media assuming other factors remain constant.
Furthermore, decreasing the flute density for filtration media can
have the effect of decreasing initial pressure drop.
[0083] Increasing the flute density of filtration media has the
effect of decreasing the flute height (J) or the flute period
length (D1), or both. As a result, the size of the flute (the size
of the flute refers to cross sectional area of the flute) tends to
decrease as flute density increases. As a result, smaller flute
sizes have the effect of increasing the pressure drop across the
filtration media. In general, the reference to a pressure drop
across the media refers to the pressure differential determined at
a first face of the media relative to the pressure measured at
second face of the media, wherein the first face and the second
face are provided at generally opposite ends of a flute. In order
to provide a filtration media having a relatively high flute
density while retaining a desired pressure drop, the flute length
can be decreased. The flute length refers to the distance from the
first face of the filtration media to the second face of the
filtration media. In the case of filtration media useful for
filtering air for combustion engines, short length flutes can be
characterized as those flutes having a flute length of less than
about 5 inches (e.g., about 1 inch to about 5 inches, or about 2
inches to about 4 inches). Medium length flutes can be
characterized as those flutes having a length of about 5 inches to
about 8 inches. Long length flutes can be characterized as those
flutes having a flute length of greater than about 8 inches (e.g.,
about 8 inches to about 12 inches).
Flute Shape
[0084] Another technique for increasing the amount of filtration
media available for filtration within a media pack includes
selecting a flute shape that provides for an increased amount of
filtration media available for filtration compared with standard
flute designs such as those described in Table 1. One technique for
providing a flute shape that increases the amount of filtration
media available for a filtration is by creating a ridge between
adjacent peaks. As discussed previously, adjacent peaks can be
characterized as an internal peak and an external peak depending
upon whether the peak is facing toward the facing sheet or away
from the facing sheet. FIGS. 4a-c show representative exemplary
flute shapes for enhancing filtration performance. The flute shape
shown in FIG. 4a can be referred to as a "low contact" flute shape.
The flute shapes shown in FIG. 4b and 4c can be referred to as a
"zero strain" flute shapes. In general, the "low contact" name
refers to the ability of the flute shape to enhance the amount of
fluted media sheet between the facing media sheets while reducing
the amount of contact (e.g., masking) between the fluted sheet and
the facing sheet compared with standard A and B fluted media. The
"zero strain" name refers to the ability of the flute shape to
provide a taper along a length of the flutes without inducing an
undesired level of strain on the media. In general, an undesired
level of strain (or elongation) in the media can refer to an amount
of strain that causes a tear or rip in the media, or an amount of
strain that requires the use of a special media that can withstand
a higher level of strain. In general, media that can withstand a
strain of greater than about 12% can be considered a special media
that an withstand a higher level of strain, and can be more
expensive than media that is equipped to handle strain up to about
12%. The zero strain fluted sheet can additionally provide for
reduced contact (e.g., reduced masking) between the fluted sheet
and the facing sheet.
[0085] Now referring to FIGS. 4a-c, the media 110 includes fluted
sheet 112 between facing sheets 111 and 113, the media 120 includes
fluted sheet 122 between facing sheets 121 and 123, and the media
140 includes fluted sheet 142 between facing sheets 141 and 143.
The combination of the fluted sheet 112 and the facing sheet 113
can be referred to as a single facer media 117, the combination of
the fluted sheet 122 and the facing sheet 123 can be referred to as
the single facer media 137, and the combination of fluted sheet 142
and facing sheet 143 can be referred to as the single facer media
147. When the single facer media 117, 137, or 147 is coiled or
stacked, the facing sheet 111, 121, or 141 can be provided from
another single facer media in the case of stacked media or from the
same single facer media in the case of coiled media.
[0086] The media 110, 120, and 140 can be arranged to provide
filter elements for cleaning a fluid such as air. The filter
elements can be arranged as coiled elements or stacked elements.
Coiled elements generally include a fluted media sheet and a facing
media sheet that is wound to provide the coiled construction. The
coil construction can be provided having a shape that is
characterized as round, obround, or racetrack. A stacked
construction generally includes alternating layers of media
comprising fluted media sheet adhered to facing media sheet. The
media 110, 120, and 140 shown in FIGS. 4a-c are sectional views
taken across the media to show the cross-sectional shape of the
fluted sheet for the low contact and zero strain shapes. It should
be understood that the cross-sectional shape can be provided
extending along a length of the flute. Furthermore, the flutes can
be sealed so that the media functions as z-media. The seal can be
provided, if desired, as an adhesive or sealant material.
[0087] In FIG. 4a, the distance D1 is measured from the center
point of the internal peak 114 to the center point of the external
peak 116. The fluted media 110 is shown having two ridges 118 for
each period length D1, or along the media length D2. The ridges 118
are provided extending along at least a portion of the length of
the flute. In general, each ridge 118 can be characterized as a
general area where a relatively flatter portion of the fluted media
118a joins a relatively steeper portion of the fluted media 118b. A
ridge (e.g., a non-peak ridge) can be considered a line of
intersection between differently sloped media portions. A ridge can
be formed as a result of deformation of the media at that location.
The media can be deformed at the ridge as a result of applying
pressure to the media. Techniques for forming the ridge include
coining, creasing, bending, and folding. Preferably, the ridge can
be provided as a result of coining during a corrugation process
where the corrugation rolls apply pressure to the media to form the
ridge. An exemplary technique for forming the fluted sheet and the
single spacer media is described in U.S. Application Ser. No.
61/025,999 that was filed with the United States Patent and
Trademark Office on Feb. 4, 2008. The entire disclosure of U.S.
Application Ser. No. 61/025,999 is incorporated herein by
reference. It is recognized that a peak can be referred to as a
ridge. In the context of this disclosure, however, the reference to
a "ridge" can be seen from context to refer to a "non-peak ridge"
when the ridge is clearly provided between peaks.
[0088] For the exemplary fluted sheet 112, the relatively flatter
portion of the fluted media 118a can be seen in FIG. 4a as the
portion of the fluted media extending between the external peak 115
and the ridge 118. The average angle of the relatively flatter
portion of the fluted media 118a from the external peak 115 to the
ridge 118 can be characterized as less than 45.degree., and can be
provided as less than about 30.degree. relative to the facing sheet
113. The relatively steeper portion of the fluted media 118b can be
characterized as that portion of the media extending from the
internal peak 116 to the ridge 118. In general, the angle of the
relatively steeper portion of the fluted media 118b, as
characterized as extending between the internal peak 116 and the
ridge 118, can be greater than 45.degree. and can be greater than
about 60.degree. relative to the facing sheet 113. It is the
difference in angle between the relatively flatter portion of the
fluted media 118a and the relatively steeper portion of the fluted
media 118b that can characterize the presence of the ridge 118. It
should be understood that the angle of the relatively flatter
portion of the fluted media 118a and angle of the relatively
steeper portion of the fluted media 118b can be determined as the
average angle between the points that form the end points of the
section of the media, and the angle is measured from the facing
sheet.
[0089] The ridge 118 can be provided as a result of coining,
creasing, bending, or folding along a length of the fluted sheet
112 during the formation of the fluted media 12. It may be
desirable, but it is not necessary, during the step of forming the
fluted media 112 to take the steps to set the ridge 118. For
example, the ridge 118 can be set by heat treatment or moisture
treatment or a combination thereof. In addition, the ridge 118 can
exist as a result of coining, creasing, bending, or folding to form
the ridge without an additional step of setting the ridge.
Furthermore, the characterization of a ridge 118 is not to be
confused with the fluted sheet external peaks 115 or 119 and the
fluted sheet internal peaks 116 or 114. The characterization of a
generally flatter portion 118a and a generally steeper portion 118b
is intended as a way to characterize the presence of a ridge. In
general, it is expected that the flatter portion 118a and the
steeper portion 118b will exhibit a curve. That is, it is expected
that the flatter portion 118a and the steeper portion 118b will not
be completely planar, particularly as fluids such as air flows
through the media during filtration. Nevertheless, the angle of the
media can be measured from the ridge to the corresponding, adjacent
peak to provide the average angle of that portion of the media.
[0090] The shape of the media depicted in FIG. 4a can be referred
to as a low contact shape. In general, the low contact shape refers
to the relatively low area of contact between the fluted sheet 112
and the facing sheet 111. The presence of the ridge 118 helps
provide for reduced masking at the peaks 115 and 119. The ridge 118
exists as a result of deforming the fluted sheet 112 and, as a
result, reduces the internal stress on the media at the peaks 115
and 119. Without the presence of the ridge 118, there would likely
exist a level of internal tension in the fluted sheet 112 that
would cause the fluted sheet 112 to create a greater radius at the
peaks 115 and 119, and thereby increase masking. As a result, the
presence of the ridge 118 helps increase the amount of media
present between adjacent peaks (e.g., peaks 115 and 114) and helps
decrease the radius of a peak (e.g., peak 115) as a result of
relieving, to a certain extent, the tension within the fluted sheet
112 that would cause it to expand or flatten out at the peaks in
the absence of the ridge.
[0091] The presence of a ridge 118 can be detected by visual
observation. FIG. 6 shows a photograph of an end view of a filter
element wherein the fluted media can be characterized as having the
low contact shape. While the presence of the low contact shape may
not be particularly apparent from viewing the end of the fluted
media, one can cut into the filter element and see the presence of
a ridge extending along a length of a flute. Furthermore, the
presence of a ridge can be confirmed by a technique demonstrated by
the photograph of FIG. 6 where the filter element is loaded with
dust, and the fluted sheet can be peeled away from the facing sheet
to reveal a cake of dust having a ridge corresponding to the ridge
on the fluted media. In general, the ridge on a cake of dust
reflects a portion of the dust surface having an average angle
intersecting another portion of the dust surface having a different
average angle. The intersection of the two portions of the dust
surface cake forms a ridge. The dust that can be used to load the
media to fill the flutes to provide a cake of dust within the
flutes can be characterized as ISO Fine test dust.
[0092] Now referring to FIG. 4a, the fluted sheet 112 includes two
ridges 118 over the distance D2 where the distance D2 refers to the
length of the fluted sheet 112 from the center point of the peak
114 to the center point of the peak 116, and wherein the ridges are
not the peaks 114, 115, 116 or 119. Although the peaks 114 and 116
can be referred to as internal peaks, and the peaks 115 and 119 can
be referred to as the external peaks, the peaks can additionally be
characterized as the facing sheet peaks. In general, it is believed
that the media will be arranged in different configurations such as
wound or stacked and that the flutes will be arranged spatially so
that the characterizations of internal and external can be
disregarded in favor of the use of the characterization of the peak
as a facing sheet peak. The use of the terms internal and external
is convenient for describing the flute as it is shown in the
figures, and as provided as part of a single facer media.
[0093] Although the fluted sheet 112 can be provided having two
ridges 118 along each length D2, the fluted sheet 112 can be
provided having a single ridge along each period length D2, if
desired, and can be provided having a configuration where some of
the periods exhibit at least one ridge, some periods exhibit two
ridges, and some periods exhibit no ridge, or any combination
thereof. The fluted sheet can be provided as having a repeating
pattern of ridges. A repeating pattern of ridges means that the
wave pattern exhibits a pattern of ridges. The pattern of ridges
may be between every adjacent peak, every other adjacent peak,
every third adjacent peak, or some variation that can be perceived
over the wave pattern of the media as exhibiting a repeating
pattern of ridges.
[0094] The characterization of the presence of a ridge should be
understood to mean that the ridge is present along a length of the
flute. In general, the ridge can be provided along the flute for a
length sufficient to provide the resulting media with the desired
performance. While the ridge may extend the entire length of the
flute, it is possible that the ridge will not extend the entire
length of the flute as a result of, for example, influences at the
ends of the flute. Exemplary influences include flute closure
(e.g., darting) and the presence of plugs at the ends of flutes.
Preferably, the ridge extends at least 20% of the flute length. By
way of example, the ridge can extend at least 30% of the flute
length, at least 40% of the flute length, at least 50% of the flute
length, at least 60% of the flute length, or at least 80% of the
flute length. The ends of the flutes may be closed in some manner
and that as a result of the closure, one may or may not be able to
detect the presence of a ridge when viewing the media pack from a
face. Accordingly, the characterization of the presence of a ridge
as extending along a length of the flute does not mean that the
ridge must extend along the entire length of the flute.
Furthermore, the ridge may not be detected at the ends of the
flute. Attention is directed to the photograph of FIG. 5 where it
may be somewhat difficult to detect the presence of a ridge at the
end of fluted media although the presence of the ridge can be
detected within the media at a distance from the end of the
flute.
[0095] Now referring to FIG. 4b, the fluted media 120 includes a
fluted sheet 122 provided between facing sheets 121 and 123. The
fluted sheet 122 includes at least two ridges 128 and 129 between
the internal peak 124 and the external peak 125. Along the length
D2, the media 122 includes four ridges 128 and 129. A single period
length of media can include four ridges. It should be understood
that the ridges 128 and 129 are not the peaks 124, 125, or 126 that
can be referred to as the facing media peaks. The media 122 can be
provided so that between adjacent peaks (e.g., peaks 125 and 126)
there are two ridges 128 and 129. In addition, the media 122 can be
provided so that between adjacent peaks, there is one ridge or no
ridge. There is no requirement that between each adjacent peak
there are two ridges. There can be an absence of ridges between
peaks if it is desirable to have the presence of ridges alternate
or be provided at predetermined intervals between adjacent
peaks.
[0096] The ridge 128 can be characterized as the area where a
relatively flatter portion of the fluted media 128a joins a
relatively steeper portion of the fluted media 128b. In general,
the relatively flatter portion of the fluted media 128a can be
characterized as having an angle of less than 45.degree. and
preferably less than about 30.degree. wherein the angle is measured
between the ridge 128 and the ridge 129, and relative to the facing
sheet 123. The relatively steeper portion of the fluted media 128b
can be characterized as having an angle of greater than 45.degree.
and preferably greater than about 60.degree. wherein the angle is
measured from the peak 126 to the ridge 128, and relative to the
facing sheet 123. The ridge 129 can be provided as a result of the
intersection of the relatively flatter portion of the fluted media
129a and the relatively steeper portion of the fluted media 129b.
In general, the relatively flatter portion of the fluted media 129a
corresponds to the angle of the portion of the media extending from
the ridge 128 to the ridge 129. In general, the relatively flatter
portion of the fluted media 129a can be characterized as having a
slope of less than 45.degree., and preferably less than about
30.degree.. The relatively steeper portion of the fluted media 129b
can be characterized as that portion of the fluted media extending
between the ridge 129 and the peak 125 and can be characterized as
having an angle between the ridge 129 and the peak 125 and relative
to the facing sheet 123. In general, the relatively steeper portion
of the fluted media 129b can be characterized as having an angle of
greater than 45.degree. and preferably greater than about
60.degree..
[0097] Now referring to FIG. 4c, the fluted media 140 includes a
fluted sheet 142 provided between facing sheets 141 and 143. The
fluted sheet 142 includes at least two ridges 148 and 149 between
the internal peak 144 and the external peak 145. Along the length
D2, the media 140 includes four ridges 148 and 149. A single period
length of media can include four ridges. It should be understood
that the ridges 148 and 149 are not the peaks 144 and 145. The
media 140 can be provided so that between adjacent peaks (e.g.,
peaks 144 and 145) there are two ridges 148 and 149. In addition,
the fluted sheet 140 can be provided so that between other adjacent
peaks, there is one ridge, two ridges, or no ridge. There is no
requirement that between each adjacent peak there are two ridges.
There can be an absence of ridges between peaks if it is desirable
to have the presence of ridges alternate or provided at
predetermined intervals between adjacent peaks. In general, a
pattern of flutes can be provided where the pattern of flutes
repeats and includes the presence of ridges between adjacent
peaks.
[0098] The ridges 148 and 149 can be characterized as the areas
where a relatively flatter portion of the fluted sheet joins a
relatively steeper portion of the fluted sheet. In the case of the
ridge 148, a relatively flatter portion of the fluted sheet 148a
joins a relatively steeper portion of the fluted sheet 148b. In the
case of the ridge 149, a relatively flatter portion of the fluted
sheet 149a joins a relatively steeper portion of the fluted sheet
149b. The relatively steeper portion of the fluted media can be
characterized as having an angle of greater than 45.degree. and
preferably greater than about 60.degree. when measured for that
portion of the media relative to the facing sheet 143. The
relatively flatter portion can be characterized as having a slope
of less than 45.degree. and preferably less than about 30.degree.
for that portion of the media relative to the facing sheet 143.
[0099] The fluted sheet 142 can be considered more advantageous to
prepare relative to the fluted sheet 122 because the wrap angle of
the fluted sheet 142 can be less than the wrap angle for the fluted
sheet 122. In general, the wrap angle refers to the sum of angles
resulting in media turns during the step of fluting. In the case of
the fluted media 142, the media is turned less during fluting
compared with the fluted media 122. As a result, by fluting to form
the fluted sheet 142, the required tensile strength of the media is
lower compared with the fluted sheet 122.
[0100] The fluted sheets 112, 122, and 142 are shown as relatively
symmetrical from peak to peak. That is, for the fluted sheets 112,
122, and 142, the flutes repeat having the same number of ridges
between adjacent peaks. Adjacent peaks refer to the peaks next to
each other along a length of fluted media. For example, for the
fluted media 112, peaks 114 and 115 are considered adjacent peaks.
A period of media, however, need not have the same number of ridges
between adjacent peaks, and the media can be characterized as
asymmetrical in this manner. That is, the media can be prepared
having a ridge on one half of the period and not having a ridge on
the other half of the period.
[0101] By providing a single ridge or multiple ridges between
adjacent peaks of the fluted media, the distance D2 can be
increased relative to prior art media such as standard A and B
flutes. As a result of the presence of a ridge or a plurality of
ridges, it is possible to provide filtration media having more
media available for filtration compared with, for example, standard
A flutes and B flutes. The previously described measurement of
media-cord percentage can be used to characterize the amount of
media provided between adjacent peaks. The length D2 is defined as
the length of the fluted sheets 112, 122, and 142 for a period of
the fluted sheets 112, 122, and 142. In the case of the fluted
sheet 112, the distance D2 is the length of the fluted sheet from
the lower peak 114 to the lower peak 116. This distance includes
two ridges 118. In the case of the fluted sheet 122, the length D2
is the distance of the fluted sheet 122 from the lower peak 124 to
the lower peak 126. This distance includes at least four ridges 128
and 129. The existence of increased filtration media between
adjacent peaks as a result of providing one or more ridge (or
crease) between the adjacent peaks can be characterized by the
media-cord percentage. As discussed previously, standard B flutes
and standard A flutes typically exhibit a media-cord percentage of
about 3.6% and about 6.3%, respectively. In general, low contact
flutes such as the flute design shown in FIG. 4a can exhibit a
media-cord percentage of about 6.2% to about 8.2%. Preferably, the
flutes exhibit a media-cord percentage greater than 5.2% and
preferably greater than 6.5%. The flute designs shown in FIGS. 5b
and 5c can provide a media-cord percentage of about 7.0% to about
16%. If desired, the media pack can be provided having flutes
exhibiting a media-cord percentage greater than about 6.3%, or
greater than about 8.3%.
[0102] The filtration media 120 and 140 in FIGS. 4b and 4c have an
additional advantage of providing the ability to taper flutes along
the length of the flute without creating a strain in the media. As
a result of this, the flute shapes referred to in FIGS. 4b and 4c
can be referred to as zero strain flute shapes. Now referring to
FIGS. 7 and 8a, the fluted sheet 122 is shown in a tapered
configuration. In FIG. 8a, the fluted sheet 122 is shown tapering
from the configuration 122a to the configuration 122d. As a result
of the taper, the fluted media includes the configurations shown as
122b and 122c. As the fluted media tapers from 122a to 122d, the
ridges 128 and the ridges 129 approach the lower peaks 126 and move
away from the upper peaks 125. Accordingly, as the fluted media 122
tapers from 122a to 122d, the cross sectional surface area between
the fluted sheet 122 and the facing sheet 123 decreases.
Corresponding with this decrease in cross sectional surface area,
the corresponding flutes formed by the fluted sheet 122 and a
facing sheet contacting the upper peaks 125 experience an increase
in cross sectional surface area. It is additionally observed that
as the taper moves toward the end configurations shown at 122a and
122d, the ridges tend to merge together or become less
distinguishable from each other. The configuration shown at 122a
tends to look more like the low contact shape. In addition, it is
seen that as the fluted media tapers from 122d to 122a, the ridges
128 and the ridges 129 approach the upper peaks 125. In the case of
the tapered zero-strain shapes, the fluted sheet can be
characterized as having multiple ridges between adjacent peaks over
at least 30%, and preferably at least 50%, of the length of the
flute.
[0103] An advantage of using the filtration media 120 where the
fluted sheet 122 contains ridges 128 and ridges 129 is the ability
to taper the flutes without creating excessive strain, and the
ability to use filtration media that need not exhibit a strain
greater than 12%. In general, strain can be characterized by the
following equation:
strain = D 2 max - D 2 min D 2 min .times. 100 ##EQU00005##
D2 min refers to the media distance where the media is relaxed or
without strain, and D2 max refers to the media distance under
strain at a point prior to tear. Filtration media that can
withstand a strain of up to about 12% without ripping or tearing is
fairly commonly used in the filtration industry. Commonly used
filtration media can be characterized as cellulosic based. In order
to increase the strain that the media can withstand, synthetic
fibers can be added to the media. As a result, it can be fairly
expensive to use media that must withstand a strain greater than
12%. Accordingly, it is desirable to utilize a flute configuration
that provides for tapering of the flute while minimizing the strain
on the media, and avoiding the necessity of using expensive media
that can tolerate higher strains than 12%.
[0104] Now referring to FIG. 8b, the fluted sheet 142 of FIG. 4c is
shown in a tapered configuration extending from locations 142a to
142b, and then to 142c. As the flute tapers to a smaller
cross-sectional area (the area between the fluted sheet 142 and the
facing sheet 143), the ridges 148 and 149 move toward the peak 145.
The reverse can also be said. That is, as the cross-sectional area
in the flute increases, the ridges 148 and 149 move toward the peak
144.
[0105] The flute shapes exemplified in FIGS. 4a-c can help provide
for reducing the area of media that may become masked at the peaks
compared with standard A and B fluted media. In addition, the
shapes exemplified in FIGS. 4a-c can help assist in increasing the
amount of media available for filtration compared with standard A
and B fluted media. In FIG. 4a, viewing the fluted media 112 from
the facing sheet 113, the ridges 118 can be seen to provide the
flute with a concave appearance. From the perspective of facing
sheet 111, the ridges 118 can be seen to provide the media
extending between adjacent peaks with a convex appearance. Now
referring to FIG. 4b, the ridges 128 and 129 can be seen as
providing both a concave and a convex appearance from either side
of the fluted media 122 from peak to adjacent peak. It should be
appreciated that the flutes are not actually concave or convex in
view of the presence of the ridges. Accordingly, the ridges provide
a transition or discontinuity in the curve. Another way of
characterizing the presence of the ridge is by observing a
discontinuity in the curve of the media wherein the discontinuity
is not present in standard A flutes and B flutes. Furthermore, it
should be appreciated that the flute shapes depicted in FIGS. 4a-4c
and 8a-8b are somewhat exaggerated. That is, after forming the
fluted media, there will likely be a degree of spring or memory in
the media that causes it to bow out or curve. Furthermore, the
application of fluid (e.g., air) through the media may cause the
media to deflect. As a result, the actual media prepared according
to this description will not necessarily follow precisely along the
drawings presented in FIGS. 4a-4c and 8a-9b.
[0106] The single facer media configurations shown in FIGS. 4a-4c
can be reversed, if desired. For example, the single facer media
117 includes the fluted sheet 112 and the facing sheet 113. If
desired, the single facer media can be constructed so that it
includes the fluted sheet 112 and the facing sheet 111. Similarly,
the single facer media shown in FIGS. 4b and 4c can be reversed, if
desired. The characterization of the single facer media shown in
FIGS. 4a-4c is provided for purposes of explaining the invention.
One will understand that a single facer media can be prepared by
combining the fluted sheet with a facing sheet in a manner
essentially opposite of that depicted in FIGS. 4a-4c. That is,
after the step of fluting the fluted sheet, the fluted sheet can be
combined with a facing sheet on either side of the fluted
sheet.
Flute Volume Asymmetry
[0107] Flute volume asymmetry refers to a volumetric difference
within a filter element or filter cartridge between the upstream
volume and the downstream volume. The upstream volume refers to the
volume of the media that receives the unfiltered fluid (e.g., air),
and the downstream volume refers to the volume of the media that
receives the filtered fluid (e.g., air). Filter elements can
additionally be characterized as having a dirty side and a clean
side. In general, the dirty side of filtration media refers to the
volume of media that receives the unfiltered fluid. The clean side
refers to the volume of media that receives the filtered fluid that
has passed via filtering passage from the dirty side. It can be
desirable to provide a media having a dirty side or upstream volume
that is greater than the clean side or downstream volume. It has
been observed that in the case of filtering air, particulates in
the air are deposited on the dirty side and, as a result, the
capacity of the filtration media can be determined by the volume of
the dirty side. By providing volume asymmetry, it is possible to
increase the volume of the media available for receiving the dirty
air and thereby increase the capacity of the media pack.
[0108] Filtration media having a flute volume asymmetry exists when
the difference between the upstream volume and the downstream
volume is greater than 10%. Filtration media have a flute volume
asymmetry can be referred to as a media pack having an asymmetric
volume arrangement. Flute volume asymmetry can be expressed by the
following formula:
volume asymmetry = volume upstream - volume downstream .times. 100
volume downstream ##EQU00006##
Preferably, media exhibiting volume asymmetry has volume asymmetry
of greater than about 10%, greater than about 20%, greater than
30%, and preferably greater than about 50%. Exemplary ranges for
flute volume asymmetry include about 30% to about 250%, and about
50% to about 200%. In general, it may be desirable for the upstream
volume to be greater than the downstream volume when it is
desirable to maximize the life of the media. Alternatively, there
may be situations where it is desirable to minimize the upstream
volume relative to the downstream volume. For example, in the case
of a safety element, it may be desirable to provide a safety
element having a relatively low upstream volume so that the media
fills and prevents flow relatively quickly as an indicator that
failure has occurred in an upstream filter element.
[0109] The volume asymmetry can be calculated by measuring the
cross-sectional surface area of flutes from a photograph showing a
sectional view of the flutes. If the flutes form a regular pattern,
this measurement will yield the flute volume asymmetry. If the
flutes are not regular (e.g., tapered), then one can take several
sections of the media and calculate the flute volume asymmetry
using accepted interpolation or extrapolation techniques.
[0110] Flute design can be adjusted to provide a flute asymmetry
that enhances filtration. In general, flute asymmetry refers to
forming flutes having narrower peaks and widened arching troughs,
or vice versa so that the upstream volume and downstream volume for
the media are different. An example of asymmetric volume
arrangement is provided in U.S. Patent Application Publication No.
US 2003/0121845 to Wagner et al. The disclosure of U.S. Patent
Application Publication No. US 2003/0121845 is incorporated herein
by reference.
[0111] Filtration media having an asymmetric volume arrangement can
result from the presence of regular flutes or tapered flutes.
Furthermore, media having relatively symmetric tapered flutes
(e.g., flutes tapering in each direct to relatively the same
extent), can provide media having a lack of an asymmetric volume
arrangement (less than 10% volume asymmetry). Accordingly, the
existence or non-existence of tapered flutes does not imply or mean
that existence or non-existence of an asymmetric volume
arrangement. Media having a regular flute arrangement (e.g.,
non-tapered) may or may not exhibit an asymmetric volume
arrangement.
[0112] The media pack can be provided so that flutes within the
media pack are both regular and tapered. For example, the flutes
can be provided so that along the length of the flute, the flute at
one portion of the length is tapered and at another portion of the
length is regular. An exemplary arrangement include, for example, a
taper-straight-taper arrangement where the flute tapers from one
face to a predetermined location and then exhibits a regular
arrangement until another predetermined location and then exhibits
a taper. The existence of a taper-straight-taper arrangement can be
use to help provide volume asymmetry, and can be used to help
handle loading and pressure drop.
Flute Closure
[0113] FIGS. 9-14 illustrate a technique for closing the ends of
flutes of z-media wherein the flutes can have the shape represented
in FIG. 4a-4c, and can be regular or tapered. FIG. 9 includes a
schematic depiction of a single facer media forming process that
includes a corrugating station 200, a single facer media forming
station 202, and a flute closure station 204. At the corrugation
station 200, two corrugated rolls 206 and 208 form a corrugating
bite 210 therebetween. A non-corrugated media sheet 212 is shown
directed into the bite 210 to be corrugated with a resulting
continuous corrugated web 214 having corrugations 216 thereacross
in a direction generally perpendicular to the machine direction 218
shown. At the single facer media forming station 202, a
non-corrugated sheet 220 is brought into engagement with side 222
of the corrugated sheet 214. The two sheets 214 and 220 can be
tacked to one another at various points there along to facilitate
the manufacturing process. To accomplish this, a tacking adhesive,
such as a hot melt, can be used. In some instances, sonic welding
can be used to effect the tacking.
[0114] An adhesive 225 can be applied to one or both of the two
sheets 214 and 220, or positioned between the two sheets 214 and
220, and can be provided in a central or intermediate location or
can be provided near an edge of the sheets 214 and 220. When
provided centrally or generally away from the edges, multiple
single facer media products can be formed. The adhesive 225 can be
used to provide a seal in the final product, and can provide for
the flute closure. The adhesive 225 can be provided as a hot melt
or as a non-hot melt adhesive. In addition, the adhesive 225 can be
provided as a strip or bead of adhesive, and the strip or bead of
adhesive can be provided as a continuous strip or bead or as a
discontinuous strip or bead. An example of a discontinuous strip or
bead is adhesive applied as droplets. The droplets can be applied
in a pattern or in a random fashion. For example, the adhesive can
be applied as a spray or printed onto one or both of the two sheets
214 and 220. The adhesive 225 is provided to hold the two sheets
214 and 220 together to form the single facer media 230 and form a
seal between the two sheets 214 and 220 so that the flute closures
are closed to the flow of fluid therethrough at the seal. While the
adhesive 225 can be applied as a continuous strip, it should be
understood that it can be applied as a discontinuous strip as long
as it results in a desired seal between the two sheets 214 and 220
and the desired flute closure to prevent flow of fluid
therethrough.
[0115] The single facer media 230 includes flutes extending between
the two sheets 214 and 220. The flutes generally extend in the
transverse direction, and the adhesive 225 can be provided
extending along the machine direction generally centrally located
across the web. Of course, placement of the adhesive 225 can vary.
In certain circumstances it may be desirable to have the adhesive
225 provided generally centrally within the web. In other
circumstances, it my desirable to have the adhesive 225 provided
closer to a side of the web. In other examples, in may be desirable
to have multiple adhesive lines extending along the web in order to
form multiple single facer medias. It should be understood that the
reference to an adhesive line refers to a general area of adhesive
applied between the fluted sheet and the facing sheet to form the
seal between the fluted sheet and the facing sheet at a flute
closure. The adhesive line can be provided as a strip of adhesive
or as a bead of adhesive, and the strip of adhesive or bead of
adhesive can be characterized, when applied, as continuous or
discontinuous, as desired to form the seal.
[0116] At the flute closure station 204, the flutes are closed
along the adhesive 225. The flute closure station 204 includes a
creaser wheel 240, a crowning wheel 250, and a flattening wheeling
260. Opposite each of the creaser wheel 240, the crowning wheel
250, and the flattening wheel 260 are rolls 242, 252, and 262. In
general, the creaser wheel 240, the crowning wheel to 250, and the
flattening wheel 260 work together to gradually flatten the fluted
sheet 214 against the facer sheet 220 at the location of the
adhesive 225. Once the single facer media has been flattened as a
result of the operation of the flattening wheel 260, the single
facer media 230 can be slit at the slitter 270 along the adhesive
225 to provide a first single facer media 272 and a second single
facer media 274. Both of the first single facer media 272 and the
second single facer media 274 can be taken up into rolls for
subsequently forming filter media packs and filter elements. The
technique illustrated in FIG. 9 that results in a first single
facer media 272 and a second single facer media 274 can be referred
to as the double wide process. An alternative double wide process
is described, in general, in U.S. Pat. No. 7,329,326. Additional
adhesive lines can be provided so that the process can be
characterized as, for example, triple wide, quadruple wide, etc.
That is, the single facer media 230 can be provided having multiple
adhesive lines (continuous or discontinuous) to thereby form
multiple single facer media portions that can be used to form media
packs. In certain situations, it may be necessary to trim one side
or edge of the single facer media thus formed in order to provide
media that has a flute closure on one side or edge and not the
other. It should be understood that process characterizations such
as, for example, triple wide and quadruple wide are a form of
double wide.
[0117] The resulting single facer media 272 and 274 can be
characterized as having a first end or a second end wherein the
fluted sheet is pressed into the facing sheet. The resulting
combination of the fluted sheet and the facing sheet pressed
together and slit at that location can be provided as a relatively
flat and substantially straight edge. Although the combination of
the fluted sheet and the facing sheeting at the edge can be bent or
curved when, for example, coiling the media to form a filtration
media pack, it is generally desirable for the edge to be relatively
straight and flat to provide desired flow properties over the edge.
That is, the edge of the single facer media having the flute
closure can be characterized as relatively straight and flat, and
the single facer media can then be bent or curved to form a
filtration media pack. Even when bent or curved to form a
filtration media pack, that edge can still be characterized as
relatively straight and flat because the curve can generally be
seen applied to the single facer media as a whole and not randomly
along the edge. The resulting pressed portion along the single
facer media can be characterized as relatively flat or flat. By
"relatively flat," it is meant that it is not "perfectly flat."
Filtration media will inherently possess surface irregularities and
those irregularities as well as potential folds may prevent the
surface from being "perfectly flat." Nevertheless, the surface can
be considered relatively flat and can be referred to as flat.
[0118] Now referring to FIG. 10, the creaser wheel 240 is shown.
The creaser wheel 240 is oriented such that its axis of rotation
241 is oriented parallel to the flute direction. This means that
the creaser wheel 240 rotates in a plane that is in a direction
transverse to the flute length. The creaser wheel 240 depicted is
shown with its axis of rotation 241 passing centrally therethrough.
The creaser wheel 240 is generally tapered at opposite surfaces 243
and 244 from a central region 245 that is adjacent the central axis
241, and extending to an end region 246. The end region 240 is
narrow, when compared to the width across the creaser wheel 240 at
the central region 245. In many embodiments, the width across the
end region 246 is less than one third the distance across the
central regions 241. In the exemplary embodiment illustrated, the
tapered surfaces 243 and 244 are tapered at an angle .alpha. less
than 10.degree., at least 1.degree., and in the particular example
1-6.degree..
[0119] The creaser wheel 240 is used to push the fluted sheet
toward the facing sheet in the single facer media. That is, the
creaser wheel 240 pushes down the fluted sheet. When the adhesive
225 is provided between the fluted sheet and the facing sheet, the
creaser wheel 240 has a tendency to push the adhesive away from the
area directly between the creaser wheel 240 and the roll 242.
[0120] Now referring to FIGS. 11 and 12, the crowning wheel 250 is
shown. In FIG. 11, a side elevational view of the crowning wheel
250 is shown. In FIG. 12, a partial end view of the crowning wheel
250 in shown. The crowning wheel 250 includes a smooth, blunt
surface 254 for engaging the fluted sheet. The surface 254, in the
example embodiment, is a toroidal surface on a radius R of at least
one inch (2.54 cm), no greater that 3 inches (7.6 cm), and
typically 1.5-2.5 inches (3.8-6.4 cm). The crowning wheel 250 has
opposite axial surfaces 255 and 256. The distance between the axial
surfaces 255 and 256 generally defines the thickness of the
crowning wheel 250. In the exemplary embodiment, the thickness is
at least 0.1 inch (0.25 cm), no greater than 0.5 inch (1.3 cm) and
typically 0.24-0.4 inch (0.5-1.0 cm). The diameter of the exemplary
crowning wheel 250 is at least 3 inches (7.6 cm), no greater than
10 inches (25.4 cm), and typically 5-9 inches. The surfaces between
each of the axial surfaces 255 and 256 and the blunt surface 254 is
curved and in the illustrated embodiment is on a radius r of at
least 0.02 inch (0.05 cm), no greater than 0.25 inch (0.6 cm), and
typically 0.08-0.15 inch (0.2-0.4 cm).
[0121] The purpose of the crowning wheel 250 is to provide further
flattening of the fluted sheet along the location where the creaser
wheel 240 contacted the fluted sheet. As the crowning wheel engages
the fluted sheet, the adhesive has the tendency to push out from
the area between the crowning wheel 250 and the roll 252.
[0122] Now referring to FIG. 13 and 14, the flattening wheel is
shown at reference number 260. The flattening wheel 260 generally
looks similar to the crowning wheel 250 with the exception that the
surface 264 is substantially flatter, and can be provided as flat.
As shown in FIG. 12, the surface 254 has a general curve. In FIG.
14, surface 264 is generally flat although it may not be perfectly
flat. That is, there may be a curve to the surface 264 but a radius
of the surface 264 should be greater than the radius of the curve
of the surface 254. The flattening wheel provides a flattening of
the fluted sheet in the area between the flattening wheel 260 and
the roll 262.
[0123] An advantage of flattening the fluted sheet for media having
the shape generally shown in FIGS. 4a-4c is that the presence of
the ridge or ridges allow for the peak of the fluted sheet to be
relatively easily depressed toward the facing sheet. That is,
because of the presence of a ridge or a plurality of ridges within
a flute period, the fluted sheet can be depressed toward the facing
sheet without the need for engaging in a darting or indenting step
as described by, for example, U.S. Patent Publication No. US
2006/0163150. Because of the presence of the ridges, the flute peak
can be depressed directly toward the facing sheet.
[0124] The flute closure technique (i.e., flattening) can be
applied to regular flutes and tapered flutes. Regular flutes, in
general, exhibit a relatively consistent size (i.e.,
cross-sectional area between the fluted sheet and the facing sheet)
along a length of the flute. In contrast, tapered flutes generally
exhibit a reduction or an increase in the cross-sectional area
along the length of the flute. Certain flutes may exhibit both
regular and tapered features. For example, a flute may have a
regular shape across a portion of the length of the flute, and then
may taper toward the end of the flute or toward a portion of the
flute and then again resume a regular shape. Regular flutes can be
flattened by the flute closure technique, and tapered flutes (or a
portion of the flute that is tapered) can be flattened by the flute
closure technique. In the case of a flute taper, either the
relatively large cross-sectional size area or the relatively small
cross-sectional size area can be flattened. In other words, the
flattening technique can be applied to the desired end of the
tapered flute. Attention is directed to FIG. 8a where the flute
closure technique can be applied, for example, at 122a or 122d.
Similarly, in the context of FIG. 8b, the flute closure can occur
at 142a or 142c.
Plug Length and Flute Height
[0125] Z-media is sometimes characterized as having flutes
extending from an inlet face to an outlet face of the media, and a
first portion of the flutes can be characterized as inlet flutes
and a second portion of the flutes can be characterized as outlet
flutes. The inlet flutes can be provided with a plug or seal near
or at the outlet face. Furthermore, the outlet flutes can be
provided with a plug or seal near or at the inlet face. Of course,
alternatives of this arrangement are available. For example, the
seals or plugs need not be provided at or adjacent to the inlet
face or outlet face. The seals or plugs can be provided away from
the inlet face or the outlet face, if desired. In the case of hot
melt adhesive being used as a seal or plug, it is often found that
the plug has a length of at least about 12 mm in standard B fluted
media. The plug length can be measured from the face of the element
to the inner surface of the plug. The applicants have found that by
reducing the plug length, it is possible to provide desirable
characteristics of the filtration media including increased loading
capacity, lower initial pressure drop, increased surface area of
media available for filtration, reduced the amount of filtration
media needed for a filter element, or combinations thereof. It can
be desirable to provide a plug length that is less than about 10
mm, less than about 8 mm, less than about 7 mm, and even more
preferably less than about 6 mm. Reducing the plug length can
provide increased performance in the situation where the flute
length is relatively short (e.g., a flute length of less than about
5 inches). Decreasing the plug length for a relatively long flute
length (e.g., greater than 8 inches) may not be as effective for
enhancing performance compared with reducing plug length for media
having a shorter flute length. For shorter length flutes, for
example, flutes having a length of less than about 5 inches (e.g.,
about 2 inches to about 4 inches), reducing the plug length to less
than about 7 mm or less than about 6 mm can provide enhanced
performance. The plug length can be referred to as an average plug
length, and can be measured as the average plug length of the plugs
sealing the first plurality of flutes or sealing the second
plurality of flutes or both. That is, the average plug length can
be reduced for the plugs present at or near one of the faces of the
media pack. There is no requirement that the average plug length is
an average plug length for all seals within the media pack. That
is, the average plug length for the first portion of flutes can be
different from the plug length for the second portion of flutes.
The average plug length can be provided as an average plug length
for all of the seals (e.g., for the first plurality of flutes and
for the second plurality of flutes), if desired.
[0126] An exemplary technique for reducing plug length is to trim
the edge of the single facer that contains sealant or adhesive
holding the fluted sheet to the facing sheet as a way to reduce the
plug length. That is, the width of single facer during production
can be longer than necessary with the understanding that the width
of the single facer will be trimmed to reduce the plug length. In
addition, the plug length can be reduced by trimming one or both
faces of the media. An alternative technique for reducing plug
length is to use a thicker or more viscous sealant material to
provide a seal or plug having a shorter length.
[0127] The flute height (J) can be selected depending upon the
desired flute height or flute size for the resulting filtration
media. The conditions of use for the filtration media can be relied
upon to select the desired flute height (J). In the case where a
filter element utilizing the media according to the present
invention is used as a substitute for a conventional filter element
that utilizes, for example, a standard B flute, the height J can be
about 0.075 inch to about 0.150 inch. In the case where a filter
element utilizing the media according to the present invention is
used as a substitute for a conventional filter element that
utilizes, for example, a standard A flute, the height J can be
about 0.15 inch to about 0.25 inch.
Exemplary Media Definitions
[0128] In the case of z-media useful for air filtration
applications, and in particular for filtering an air stream for an
internal combustion engine, the definition of the filtration media
can be selected depending upon whether the filtration media is
intended maximize dust loading capacity, minimize pressure drop, or
provide a desirable level of both capacity and pressure drops. The
dust loading capacity can refer to the life or longevity of the
filtration media. Sometimes it is desirable to design a filtration
media that is capable of exhibiting a desired life span before it
needs to be replaced. Alternatively, in certain circumstances, it
may be more desirable to design a filtration media that is capable
of performing within a desired pressure drop range. The selection
of various definitions for the filtration media provides the
flexibility for defining the filtration media for a particular
environment and for a particular air cleaner. In addition,
selecting the various definitions of the filtration media allows
one to have flexibility in designing an air cleaner to fit a
particular environment.
[0129] The following described exemplary filtration media can be
provided with or without the flute shape referred to earlier as
"low contact" or "zero strain." The provision of a ridge or
multiple ridges between peaks in a fluted media is not a
requirement of the filtration media, but can be relied upon for
enhancing performance.
[0130] A first exemplary filtration media can be selected for
maximizing dust loading capacity. The flute density can be selected
so that it is greater than the flute density of filter media
prepared from Standard B flute media. For example, the filtration
media can be provided having a flute density of at least about 35.0
flute/inch.sup.2, wherein the flute density is calculated according
to the formula:
.rho. = number of channels ( open and closed ) 2 .times. z - media
pack cross sectional area ##EQU00007##
wherein the number of channels is determined by counting the
channels in a cross section of the media and the location where the
media cross sectional area is determined. Preferably, the flute
density can be greater than 45 flute/inch.sup.2 or greater than
about 50 flute/inch.sup.2. In order to reduce pressure drop caused
by the increase in flute density, the flute length can be
decreased. For example, the media can be provided having a flute
length of less than 5 inches. Because of the relatively short flute
length, the plug length can be provided as relatively short in
order to increase the amount of media available for filtration. For
example, the plugs can be provided having a length of less than
about 7 mm, and preferably less than about 6 mm. In addition, the
flute volume asymmetry of the media can be adjusted. For example,
the flute volume asymmetry of the media can be provided so that the
upstream volume is at least 10 percent greater than the downstream
volume. Preferably, the flute volume asymmetry can be greater than
30%, and preferably greater than 50%. The fluted media can be
provided having a flute width height ratio of at least about 2.7,
and preferably at least about 3.0.
[0131] A second exemplary media can be selected for providing a
desired long life. The second exemplary media can have a medium
flute length. For example, the flute length can be about 5 inches
to about 8 inches. The second exemplary media can be provided
without a taper, and can be provided having a flute density of
about 34 flutes/inch.sup.2 which is about the flute density of
Standard B media. The second exemplary media can be provided having
a flute width height ratio of greater than about 2.7, and
preferably greater than about 3.0. In addition, the second
exemplary media can be provided having a flute volume asymmetry of
greater than 20%, and preferably greater than 30%.
[0132] A third exemplary filtration media can be provided so that
the media exhibits a desired low pressure drop. The third exemplary
filtration media can have a relatively low flute density of less
than about 34 flute/inch.sup.2, and preferably less than about 25
flute/inch.sup.2. In addition, the flute length of the media can be
medium length or long, and can have a length of at least about 5
inches and can have a length of about 6 inches to about 12 inches.
The third exemplary filtration media can be provided with or
without flute volume asymmetry. When provided with flute volume
asymmetry, the media can have a flute volume asymmetry of greater
than about 30%, or greater than about 70%. The flutes can be
provided as tapered or non-tapered.
[0133] A fourth exemplary filtration media can be provided to
balance the desired level of dust loading and the desired pressure
drop. The fourth exemplary filtration media can be provided having
relatively long flutes. For example, the flute length of the media
can be about 8 inches to about 12 inches. The fourth exemplary
filtration media can be provided with or without a taper.
Filter Elements
[0134] Now referring to FIGS. 15-24, filter elements are described
that include a filtration media pack. The filtration media pack can
be provided based upon the media pack characterizations described
herein, and based upon the exemplary media definitions. One will
understand how the filter elements shown in FIGS. 15-24 can be
modified to accept the media as characterized herein. For example,
the media can be provided as coiled or stacked, and can be provided
having a flute length and flute density range as described. In
addition, the filter elements shown in FIGS. 15-24 are generally
characterized as air filtration elements because they can be used
to filter air.
[0135] The filtration media pack can be provided as part of a
filter element containing a radial seal as described in, for
example, U.S. Pat. No. 6,350,291, U.S. Patent Application No. US
2005/0166561, and International Publication No. WO 2007/056589, the
disclosures of which are incorporated herein by reference. For
example, referring to FIG. 15, the filter element 300 includes
filtration media pack 301 that can be provided as a wound media
pack 302 of single facer media, and can include a first face 304
and a second face 306. A frame 308 can be provided on a first end
of the media pack 310, and can extend beyond the first face 304.
Furthermore, the frame 308 can include a step or reduction in
circumference 312 and a support 314 that extends beyond the first
face 304. A seal member 316 can be provided on the support 314.
When the filter element 301 is introduced within the housing 320,
the seal member 316 engages the housing sealing surface 322 to
provide a seal so that unfiltered air does not bypass the
filtration media pack 300. The seal member 316 can be characterized
as a radial seal because the seal member 316 includes a seal
surface 317 that engages the housing sealing surface 322 in a
radial direction to provide sealing. In addition, the frame 308 can
include a media pack cross brace or support structure 324 that
helps support the frame 308 and helps reduce telescoping of the air
filtration media pack 300. An access cover 324 can be provided for
enclosing the filter element 300 within the housing 320.
[0136] The filtration media pack can be provided as part of a
filter element having a variation on the radial seal configuration.
As shown in FIG. 16, the seal 330 can be relied upon for holding
the frame 332 to the media pack 334. As shown in FIG. 15, the frame
308 can be adhesively attached to the media pack 301. As shown in
FIG. 16, the frame 332 can be provided adjacent to the first face
336 and the seal 330 can be provided so that it holds the support
332 onto the media pack 334 without the use of additional adhesive.
The seal 330 can be characterized as an overmold seal in that it
expands along both sides of the seal support 338 and onto the outer
surface of the media pack 334 at the first end 340.
[0137] The filtration media pack can be provided as part of a
filter element according to U.S. Pat. No. 6,235,195, the entire
disclosure of which is incorporated herein by reference. Now
referring to FIG. 17, the filter element 350 includes a wound media
pack 352 having an oblong or racetrack shape, and an axial pinch
seal 354 attached to the end and circumscribing the exterior of the
media pack. The axial pinch seal 354 is shown provided between the
first face 356 and the second face 358 of the media pack. The axial
pinch seal 354 includes a base portion 360 and a flange portion
362. The base portion 362 can be provided for attaching to the
media pack. The flange portion 362 can be pinched between two
surfaces to create a seal. One of the surfaces can be a surface of
the housing that contains the filter element 350. In addition, the
other structure that pinches the flange 362 can be an access cover
or another structure provided within the housing that helps
maintain the seal so that unfiltered air passes through the media
pack without bypassing the media pack. The filter element 350 can
include a handle 364 extending axially from the first face 356. If
desired, the handle can be provided extending axially from the
second face 358. The handle 364 allows one to pull or remove the
filter element 350 from the housing.
[0138] Now referring to FIGS. 18-20, a filter element is shown at
reference number 400. The filter element 400 includes a wound media
pack 402, a handle arrangement 404, and a seal arrangement 406.
Details of this filter element construction can be found in U.S.
Pat. No. 6,348,084, the entire disclosure of which is incorporated
herein by reference. The previously described single facer media
can be used to prepare the filter element 400.
[0139] The handle arrangement 404 includes a center board 408,
handles 410, and a hook construction 412. The single facer media
can be wound around the center board 408 so that the handles 410
extend axially from a first face 414 of the media pack 402. The
hook arrangement 412 can extend from the second face 416 of the
media pack 402. The handles 410 allow an operator to remove the
filter element 400 from a housing. The hook construction 412
provides for attachment to a cross brace or support structure 420.
The hook construction 412 includes hook members 422 and 424 that
engage the cross brace or support structure 420. The cross brace or
support structure 420 can be provided as part of a seal support
structure 430 that extends from the second face 416 and includes a
seal support member 432. A seal 434 can be provided on the seal
support member to provide a seal between the filter element 400 and
a housing. The seal 434 can be characterized as a radial seal when
the seal is intended to provide sealing as a result of contact of a
radially facing seal surface 436 and a housing seal surface.
[0140] The filtration media pack can be provided as part of a gas
turbine system as shown in U.S. Pat. No. 6,348,085, the entire
disclosure of which is incorporated herein by reference. An
exemplary gas turbine filtration element is shown at reference
number 450 in FIG. 21. The filter element 450 can include a primary
filter element 452 and a secondary filter element 454. The
secondary filter element 454 can be referred to as a safety filter
element. The main filter element 452 can be provided as an
filtration media pack as previously described in this application.
The filtration media pack can be provided as a result of winding a
single facer media or as a result of stacking a single facer media.
The primary filter element 452 and the secondary filter element 454
can be secured within a sleeve member 460. The sleeve member 460
can include a flange 462 that includes a seal 464. When installed,
the element 450 can be provided so that the flange 462 and seal 464
are provided adjacent a support 466 and held in place by a clamp
200 so that the seal 464 provides a sufficient seal so that
unfiltered air does not bypass the filter element 450.
[0141] Another filter element that can utilize the filtration media
pack is described in U.S. Pat. No. 6,610,126, the entire disclosure
of which is incorporated herein by reference. Now referring to FIG.
22, the filter element 500 includes an filtration media pack 502, a
radial seal arrangement 504, and a dust seal or secondary seal
arrangement 506. The filter element 500 can be provided within an
air cleaner housing 510 and can include, downstream of the filter
element 500, a safety or secondary filter element 512. Furthermore,
an access cover 514 can be provided for enclosing the housing 510.
The housing 510 and the access cover 514 can pinch the dust seal
506 so that the dust seal 506 can be characterized as a pinch
seal.
[0142] The filtration media pack can be provided as a stacked media
pack arrangement according to International Publication No. WO
2006/076479 and International Publication No. WO 2006/076456, the
disclosures of which are incorporated herein by reference. Now
referring to FIG. 23, a filter element is shown at reference number
600 that includes a stacked, blocked, media pack 602. The blocked
stacked media pack 602 can be characterized as a rectangular or
right (normal) parallelogram media pack. To seal the opposite ends
of the media pack 602 are positioned side panels 604 and 606. The
side panels 604 and 606 seal the lead end and tail end of each
stacked, single facer media. The media pack 602 has opposite flow
faces 610 and 612. It is pointed out that no flow path between
faces 610 and 612 is provided that does not also require the air to
pass through media of the media pack 602 and thus to be filtered. A
peripheral, perimeter, housing seal ring 614 is positioned in the
air filter element 600. The particular seal ring 614 depicted is an
axial pinch seal ring. If desired, a protective sheath or panel can
be provided over the media pack surfaces 626 and 622.
[0143] The filtration media pack can be provided as a stacked media
pack arrangement according to International Publication No. WO
2007/133635, the entire disclosure of which is incorporated herein
by reference. Now referring to FIG. 24, a filter element is shown
at reference number 650. The filter element 650 includes a stacked
z-filter media arrangement 652 having a first, in this instance,
inlet face 654, and an opposite second, in this instance, outlet
face 656. In addition, the filter element 650 includes an upper
side 660, a lower side 662, and opposite side end 664 and 666. The
stacked z-filter media arrangement 652 generally comprises one or
more stacks of strips of single facer media where each strip
comprises a fluted sheet secured to a facing sheet. The strips can
be provided in a slanted arrangement. The strips are organized with
flutes extending between the inlet face 654 and the outlet face
656. The filter element 650 depicted comprises a stacked z-filter
media pack arrangement comprising two stacked media pack sections
670 and 672. A seal member 680 can be molded to the media pack. In
addition, the filter element 650 includes an axially extending
handle 682. The axially extending handle 682 can be provided having
a first handle 684 and a second handle 686. The handle 682 can be
attached to a center board extending within the media pack wherein
the single facer media can be sealed to the center board.
[0144] It should be appreciated that, in view of exemplary FIGS.
15-24, that the filtration media pack can be provided in various
configurations to form filter elements that can then be used in
various housing arrangements to provide enhanced performance.
[0145] The above specification provides a complete description of
the manufacture and use of the filtration media and filter element
of the invention. Since many embodiments of the invention can be
made without departing from the spirit and scope of the invention,
the invention resides in the claims hereinafter appended.
* * * * *