U.S. patent number RE42,174 [Application Number 12/363,587] was granted by the patent office on 2011-03-01 for filter with efficiently sealed end.
This patent grant is currently assigned to Cummins Filtration IP, Inc.. Invention is credited to Thomas A. Fosdal, Larry T. Gunderson, Kelly R. Schmitz, Gregory J. Schoenmann.
United States Patent |
RE42,174 |
Gunderson , et al. |
March 1, 2011 |
Filter with efficiently sealed end
Abstract
.[.A filter element has a resiliently compressible end cap at a
first axial end sealing the filter and providing sealed engagement
with a flow tube..]. .Iadd.A filter assembly comprising a filter
media element having a first end and a second end, a first end cap
disposed at the first end, and a second end cap disposed at the
second end. The filter media element is shaped to form a hollow
interior extending from the first end to the second end. The hollow
interior defines an inner boundary of the element and the outer
surface of the element defines an outer boundary. The second end
cap covers both the filter media element and the hollow interior at
the second end..Iaddend.
Inventors: |
Gunderson; Larry T. (Madison,
WI), Fosdal; Thomas A. (Stoughton, WI), Schoenmann;
Gregory J. (Stoughton, WI), Schmitz; Kelly R.
(Stoughton, WI) |
Assignee: |
Cummins Filtration IP, Inc.
(Minneapolis, MN)
|
Family
ID: |
32326637 |
Appl.
No.: |
12/363,587 |
Filed: |
January 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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11759884 |
Jun 7, 2007 |
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Reissue of: |
10428459 |
May 2, 2003 |
06902598 |
Jun 7, 2005 |
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Current U.S.
Class: |
55/498; 55/510;
55/502 |
Current CPC
Class: |
B01D
46/2414 (20130101); B01D 29/908 (20130101); B01D
46/523 (20130101); B01D 29/21 (20130101); B01D
2271/02 (20130101); B01D 2201/127 (20130101); B01D
2201/34 (20130101) |
Current International
Class: |
B01D
35/30 (20060101) |
Field of
Search: |
;55/385.3,498,502,510
;123/198E |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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3001674 |
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Jul 1981 |
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DE |
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3405719 |
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Aug 1985 |
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DE |
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1131647 |
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Oct 1956 |
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FR |
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2261041 |
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Dec 1975 |
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FR |
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1499922 |
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Feb 1978 |
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GB |
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21100110 |
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Jun 1983 |
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GB |
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Primary Examiner: Hopkins; Robert A
Attorney, Agent or Firm: Andrus, Sceales, Starke &
Sawall, LLP Schelkopf; J. Bruce
Parent Case Text
.Iadd.CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. Reissue patent
application Ser. No. 11/759,884, filed Jun. 7, 2007, which is a
reissue of U.S. Pat. No. 6,902,598 and incorporated herein by
reference..Iaddend.
Claims
What is claimed is:
.[.1. A filter element comprising pleated filter media having a
plurality of pleats in a closed loop having an outer perimeter
defined by a plurality of outer pleat tips, and an inner perimeter
defined by a plurality of inner pleat tips, said loop having a
hollow interior extending along a given axis, wherein fluid flows
axially in said hollow interior, said filter element having first
and second axial ends, said first axial end being open and
providing an axial flow passage therethrough along said axis
communicating with said hollow interior, a resiliently compressible
end cap at said first axial end covering said inner and outer pleat
tips and spanning radially between said inner and outer perimeters,
a flow tube communicating with said hollow interior and extending
along said axial flow passage and engaging said end cap, wherein
said flow tube at said engagement with said end cap has an inner
perimeter greater than said inner perimeter defined by said inner
pleat tips, and comprising in combination a second end cap at said
second axial end of said filter element covering said inner and
outer pleat tips and spanning radially between said inner and outer
perimeters and also spanning said hollow interior and closing said
second axial end of said filter element..].
.[.2. The filter element according to claim 1 wherein said inner
perimeter of said flow tube at said engagement with said end cap is
less than said outer perimeter defined by said outer pleat
tips..].
.[.3. The filter element according to claim 2 wherein said end cap
has a first section extending radially inwardly from said outer
perimeter defined by said outer pleat tips, and has a second
section extending radially outwardly from said inner perimeter
defined by said inner pleat tips, said first and second sections
meeting at a junction defining a step facing radially toward and
engaging said flow tube..].
.[.4. The filter element according to claim 3 wherein said step has
a first axial length, said flow tube has a tubular portion
extending axially along said step, said tubular portion having an
inner axial end axially facing said first axial end of said filter
element, and said flow tube has a flange portion extending radially
from said tubular portion and facing said first axial end of said
filter element and axially spaced from said inner axial end of said
tubular portion by a second axial length less than said first said
axial length..].
.[.5. The filter element according to claim 3 wherein said end cap
has a first axial thickness at said first section at said outer
perimeter defined by said outer pleat tips, a second axial
thickness at said first section at said step, a third axial
thickness at said second section at said step, and a fourth axial
thickness at said second section at said inner perimeter defined by
said inner pleat tips, and wherein said second axial thickness is
greater than said third axial thickness..].
.[.6. The filter element according to claim 5 wherein said first
axial thickness is greater than said fourth axial thickness..].
.[.7. The filter element according to claim 5 wherein said first
axial thickness is less than said second axial thickness..].
.[.8. The filter element according to claim 5 wherein said third
and fourth axial thicknesses are substantially the same..].
.[.9. The filter element according to claim 1 comprising a housing
containing said filter element, said housing having an end wall
axially facing said first axial end of said filter element, and
wherein said flow tube is part of said end wall..].
.[.10. The filter element according to claim 1 wherein fluid flows
laterally radially through said filter element between said outer
and inner perimeters, and flows axially in said hollow
interior..].
.[.11. A filter element comprising a closed loop filter media
member having a hollow interior extending along a given axis,
wherein fluid flows axially in said hollow interior, said filter
element having first and second axial ends, said first axial end
being open and providing an axial flow passage therethrough along
said axis communicating with said hollow interior, a resiliently
compressible end cap at said first axial end, a flow tube
communicating with said hollow interior and extending along said
axial flow passage, said flow tube having a tubular portion
engaging said end cap and forming a seal therewith, said tubular
portion being cylindrical, said filter media member being
non-cylindrical..].
.[.12. The filter element according to claim 11 wherein said filter
media member is elliptical..].
.[.13. The filter element according to claim 11 wherein said end
cap has a first section extending radially inwardly from an outer
perimeter, and has a second section extending radially inwardly
from said first section to an inner perimeter, said first and
second sections meeting at a junction defining a step, said first
section having said outer perimeter and having an inner perimeter
at said step, said second section having an outer perimeter at said
step and having said inner perimeter communicating with said hollow
interior, said outer perimeter of said first section being
non-cylindrical, said inner perimeter of said first section being
cylindrical, said step being cylindrical, said outer perimeter of
said second section being cylindrical..].
.[.14. The filter element according to claim 13 wherein said
cylindrical tubular portion engages said end cap at said
cylindrical step..].
.[.15. The filter element according to claim wherein said inner
perimeter of said second section is non-cylindrical..].
.[.16. The filter element according to claim 13 wherein said filter
media member and said outer perimeter of said first section of said
end cap are elliptical and have a radially extending major axis and
a radially extending minor axis, wherein the radial extension of
said first section of said end cap along said major axis between
said outer perimeter of said first section of said end cap and said
step is greater than the radial extension of said first section of
said end cap along said minor axis between said outer perimeter of
said first section of said end cap and said step, and wherein the
radial extension of said second section of said end cap along said
minor axis between said step and said inner perimeter of said
second section of said end cap is greater than the radial extension
of said o second section of said end cap section along said major
axis between said step and said inner perimeter of said second
section of said end cap..].
.[.17. The filter element according to claim 11 wherein said filter
media member comprises pleated filter media having a plurality of
pleats in a closed loop having an outer perimeter defined by a
plurality of outer pleat tips, and an inner perimeter defined by a
plurality of inner pleat tips, said loop having said hollow
interior extending along said given axis..].
.Iadd.18. A filter comprising pleated filter media having a
plurality of pleats in a closed loop having an outer perimeter
defined by a plurality of outer pleat tips, and an inner perimeter
defined by a plurality of inner pleat tips, said loop having a
hollow interior extending along a given axis, wherein fluid flows
axially in said hollow interior, said filter having first and
second axial ends, said first axial end being open and providing an
axial flow passage therethrough along said axis communicating with
said hollow interior, a resiliently compressible first end cap at
said first axial end covering said inner and outer pleat tips and
spanning radially between said inner and outer perimeters, a second
end cap at said second axial end of said filter covering said inner
and outer pleat tips and spanning radially between said inner and
outer perimeters and also spanning said hollow interior and closing
said second axial end of said filter, and an outer liner
circumscribing said filter..Iaddend.
.Iadd.19. The filter according to claim 18 wherein said outer liner
circumscribes said filter at at least one of said pleated filter
media and said first end cap..Iaddend.
.Iadd.20. The filter according to claim 19 wherein said outer liner
circumscribes said filter at said pleated filter
media..Iaddend.
.Iadd.21. The filter according to claim 20 wherein said outer liner
circumscribes the entire said pleated filter media from said first
axial end to said second axial end..Iaddend.
.Iadd.22. The filter according to claim 19 wherein said outer liner
circumscribes said filter at said first end cap..Iaddend.
.Iadd.23. The filter according to claim 22 wherein said outer liner
circumscribes a portion of said first end cap..Iaddend.
.Iadd.24. The filter according to claim 19 wherein said outer liner
circumscribes said filter at both of said pleated filter media and
said first end cap..Iaddend.
.Iadd.25. The filter according to claim 24 wherein said outer liner
is a single one-piece member..Iaddend.
.Iadd.26. The filter according to claim 18 wherein said first end
cap has a first section extending radially inwardly from said outer
perimeter defined by said outer pleat tips, and has a second
section extending radially outwardly from said inner perimeter
defined by said inner pleat tips, said first and second sections
meeting at a junction defining a step..Iaddend.
.Iadd.27. The filter according to claim 26 wherein said first end
cap has a first axial thickness at said first section at said outer
perimeter defined by said outer pleat tips, a second axial
thickness at said first section at said step, a third axial
thickness at said second section at said step, and a fourth axial
thickness at said second section at said inner perimeter defined by
said inner pleat tips, and wherein said second axial thickness is
greater than said third axial thickness..Iaddend.
.Iadd.28. The filter according to claim 27 wherein said first axial
thickness is greater than said fourth axial thickness..Iaddend.
.Iadd.29. The filter according to claim 27 wherein said first axial
thickness is less than said second axial thickness..Iaddend.
.Iadd.30. The filter according to claim 27 wherein said third and
fourth axial thicknesses are substantially the same..Iaddend.
.Iadd.31. The filter according to claim 18 wherein said first end
cap is configured to receive a flow tube communicating with said
hollow interior and extending along said axial flow passage and
engaging said first end cap, wherein said flow tube at said
engagement with said first end cap has an inner perimeter greater
than said inner perimeter defined by said inner pleat tips, wherein
said first end cap bears radially between said outer liner and said
flow tube..Iaddend.
.Iadd.32. The filter according to claim 31 wherein said outer liner
has at least a portion circumscribing said filter at and extending
axially into said first end cap..Iaddend.
.Iadd.33. The filter according to claim 18 wherein said outer liner
has a first section circumscribing said pleated filter media at
said outer pleat tips, and a second section extending into said
first end cap..Iaddend.
.Iadd.34. The filter according to claim 33 wherein said outer liner
is a unitary one-piece member, and said second section extends
integrally from said first section..Iaddend.
Description
BACKGROUND AND SUMMARY
The invention relates to fluid filters, and more particularly to
improved sealing of the filter media end.
The invention arose during continuing development efforts relating
to filter elements having pleated filter media having a plurality
of pleats in a closed loop, typically annular, for example as shown
in U.S. Pat. Nos. 6,149,700, 6,261,334, 6,391,076, 6,398,832, all
incorporated herein by reference. The closed loop pleated filter
media has an outer perimeter defined by a plurality of outer pleat
tips, and an inner perimeter defined by a plurality of inner pleat
tips, and has a hollow interior extending along a given axis. Fluid
flows axially in the hollow interior, before or after flow through
the media, depending on whether the flow is inside-out or
outside-in. The filter element has an open axial end providing an
axial flow passage therethrough along the axis communicating with
the hollow interior.
The present invention relates to improved sealing of the pleat ends
at the open axial end of the filter element, including improvements
in both the effectiveness of the sealing and manufacturing
efficiency for cost reduction. The invention further relates to
other filter media end sealing techniques.
BRIEF DESCRIPTION OF THE DRAWINGS
Prior Art
FIG. 1 is taken from FIG. 1 of incorporated U.S. Pat. No.
6,149,700.
FIG. 2 is taken from FIG. 2 of the noted incorporated '700 patent
and is a sectional view taken along line 2--2 of FIG. 1.
FIG. 3 illustrates prior art and shows the open axial end of a
closed loop pleated media filter element prior to potting of the
end cap.
FIG. 4 illustrates prior art and shows the open axial end of the
filter element of FIG. 3 after potting of the end cap.
FIG. 5 is taken from FIG. 11 of the incorporated '700 patent, and
is a view of a mold for molding an end cap onto pleated filter
media of a filter element.
FIG. 6 is taken from FIG. 10 of the incorporated '700 patent, and
is a view like a portion of FIG. 2, and shows an alternate
embodiment.
Present Invention
FIG. 7 is like FIG. 2 and shows the present invention.
FIG. 8 is like FIG. 3 and shows the present invention.
FIG. 9 is like FIG. 4 and shows the present invention.
FIG. 10 is like FIG. 5 and shows the present invention.
FIG. 11 is like FIG. 6 and shows the present invention.
FIG. 12 is like FIG. 7 and shows a further embodiment.
FIG. 13 is like FIG. 7 and shows a further embodiment.
FIG. 14 is like FIG. 9 and shows a further embodiment.
DETAILED DESCRIPTION OF THE INVENTION
Prior Art
FIGS. 1 and 2 show a filter 20 including a filter element 22
contained within a housing 24. Filter element 22 is provided by
pleated filter media 26, FIG. 2, having a plurality of pleats 28,
FIGS. 3, 4, in a closed loop, typically an annulus, having an outer
perimeter 30 defined by a plurality of outer pleat tips 32, and an
inner perimeter 34 defined by a plurality of inner pleat tips 36.
The annular closed loop has a hollow interior 38 extending along an
axis 40. Housing 24 is typically cylindrical and is provided by
housing sections 42 and 44 mounted to each other in conventional
manner such as by overcenter spring clip type clamps such as 46, or
in other suitable manner. The housing has an inlet 50 admitting
inlet fluid, such as air or liquid, radially and/or tangentially
into annular space 52 within the housing around filter element 22.
Alternatively, the inlet may be at an axial end of the housing, for
example as in incorporated U.S. Pat. No. 6,391,076. The housing may
include an interior dam or deflection surface 54 for blocking
direct impact against filter element 22 and/or for directing flow,
for example in a spiral or toroidal pattern. The fluid flows
laterally or radially inwardly through filter media 26 into hollow
interior 38, and then the clean fluid flows axially rightwardly in
FIG. 2 in hollow interior 38 along flow passage 56 as shown at
arrows 58, 59. Alternatively or additionally, the fluid may flow
axially through the filter media as in the noted incorporated '076
patent.
Flow passage 56 extending along axis 40 circumscribes hollow
interior 38 and has a flow perimeter 60 greater than inner
perimeter 34 defined by inner pleat tips 36, as described in the
incorporated '700 patent. Flow perimeter 60 is less than outer
perimeter 30 defined by outer pleat tips 32. Inner perimeter 34
defines and bounds a first cross-sectional area. Flow perimeter 60
defines and bounds a second cross-sectional area. The second
cross-sectional area is greater than the first cross-sectional
area. Outer perimeter 30 defines and bounds a third cross-sectional
area. The second cross-sectional area is less than the third
cross-sectional area. Filter element 22 has first and second axial
ends 62 and 64. Axial end 62 is open and provides axial flow
passage 56 therethrough. An end cap 66 of soft resilient
compressible material, such as foamed potted urethane, axially
abuts the axial ends 68 of the pleats. End cap 66 has an inner
perimeter 70 greater than inner perimeter 34 defined by inner pleat
tips 36. End cap 66 partially covers the axial ends 68 of the
pleats such that the laterally outward portions 72 of the axial
ends 68 of the pleats 28 are covered by end cap 66 but not the
laterally inward portions 74 of the axial ends 68 of the pleats,
such that the laterally inward portions 74 of the axial ends of the
pleats are uncovered and exposed at axial end 62 of filter element
22, FIG. 4.
In one embodiment, second axial end 64 of filter element 22 is
closed. A second end cap 76, FIG. 2, of soft compressible resilient
material, such as foamed potted urethane, is provided at second end
64 of filter element 22 and completely covers the axial ends 78 of
the pleats including the outer pleat tips 32 and the inner pleat
tips 36 at axial end 64. End cap 76 also includes a central section
80 spanning and completely covering hollow interior 38 of filter
element 22 at axial end 64 of the filter element. Housing section
44 includes an annular interior sidewall 82 extending partially
axially into the housing to locate and retain filter element 22 at
axial end 64. In other embodiments, central section 80 of end cap
76 is omitted, and a portion of housing 44 extends into hollow
interior 38 of filter element 22 to close axial end 64 of the
filter element and to position axial end 64 of the filter element
within the housing. Further embodiments are shown in the noted
incorporated '076 patent. End cap 76 includes an annular ridge 84
engaging axial end wall 85 of housing section 44 and slightly
axially compressed thereagainst to further aid in retention of
filter element 22 within the housing and to accommodate axial
tolerances. End cap 66 also includes an annular ridge 86 engaging
axial end wall 88 of housing section 42 and slightly radially
compressed thereagainst to aid in retaining filter element 22
within the housing and to accommodate axial tolerances and also to
provide an axial seal to prevent bypass of dirty air from annular
chamber 52 around axial end 62 of the filter element. Axial end
wall 88 of housing section 42 has an outlet flow tube 90 extending
therethrough. In addition to or alternatively to the axial seal at
86, end cap 66 provides a radial seal at 70 against outlet flow
tube 90.
End cap 66 has a sidewall 92 extending axially away from axial ends
68 of pleats 28 at axial end 62 of filter element 22. The sidewall
has the noted inner perimeter 70, and has an outer perimeter 94. As
noted above, inner perimeter 70 of sidewall 92 is greater than
inner perimeter 34 of filter element 22 defined by inner pleat tips
36. Inner perimeter 70 of sidewall 92 of end cap 66 is less than
outer perimeter 30 of filter element 22 defined by outer pleat tips
32. Outer perimeter 94 of sidewall 92 of end cap 66 is greater than
outer perimeter 30 of filter element 22 defined by outer pleat tips
32. Flow tube 90 has an inner section 96 axially facing the axial
ends 68 of pleats 28. Inner section 96 of flow tube 90 has an inner
perimeter 98 and an outer perimeter 100. Outer perimeter 100 is
greater than inner perimeter 70 of sidewall 92 of end cap 66, such
that as filter element 22 at end cap 66 is axially slid rightwardly
over inner section 96 of flow tube 90, end cap 66 is radially
compressed to expand inner perimeter 70 along outer sidewall 100 of
flow tube inner section 96 to effect the noted radial seal. Inner
perimeter 70 of end cap 66 is preferably stepped, as shown at 71 in
FIG. 8 of the noted incorporated '700 patent, to have slightly
progressively decreasing diameters from right to left as viewed
therein, to receive and guide inner section 96 of flow tube 90
therealong and increase radial sealing pressure. End cap 66
circumscribes inner section 96 of flow tube 90 and bears radially
thereagainst at 70 in sealing relation to form the noted radial
seal thereat. End wall 88 of housing section 42 axially faces axial
ends 68 of pleats 28, and end cap 66 also bears axially against end
wall 88 in sealing relation at 86 to form the noted axial seal
thereat.
An outer liner 102, FIG. 2, provided by an expanded wire mesh or
screen or perforated metal or plastic, circumscribes filter element
22 along outer pleat tips 32 and has an axial end section 104
extending axially beyond the axial ends 68 of pleats 28. An inner
liner may also be provided at inner perimeter 34 along inner pleat
tips 36. As above described, flow tube 90 communicates with hollow
interior 38 of the filter element along flow passage 56 and extends
axially from the axial end of the filter element. End cap 66 at the
axial end of the filter element bears radially between and is
radially compressed between and against section 104 of outer liner
102 and inner section 96 of flow tube 90. Outer liner 102 extends
axially at 104 into end cap 66 and is potted therein during the
molding process, as described in the incorporated '700 patent. As
noted above, sidewall 92 of end cap 66 extends axially away from
the axial ends 68 of pleats 28 at the axial end of the filter
element. Outer perimeter 94 of the end cap sidewall circumscribes
outer liner section 104. The filter element may also include an
inner liner 103, FIG. 5, along inner pleat tips 36.
Pleats 28 have pairs of walls defining axially extending interior
channels 106, FIG. 3, and also as shown in FIG. 7 of the
incorporated '700 patent, and axially extending exterior channels
108. The walls of the pleats defining the exterior channels 108 are
sealed to each other near axial end 62 of the filter element by
heat seal bonding along glue strips, also known as hot melt, such
as 110, and as shown in the incorporated '700 patent at FIGS. 4-6,
9, and for example as disclosed in U.S. Pat. No. 5,106,397,
incorporated herein by reference. This prevents bypass of dirty air
around the axial ends of the pleats at inner exposed portions 74.
Fluid such as air flowing radially inwardly through the filter
media as shown at 112, and as shown in the incorporated '700 patent
at FIG. 4, or alternatively flowing axially as shown in the
incorporated '076 patent at FIGS. 15, 16 thereof, must flow through
the sidewalls of pleats 28 before such fluid can flow axially
through hollow interior 40 as shown at arrow 58 or axially through
the inward portions 74 of the axial ends 68 of the pleats as shown
at arrow 59. Some of such air can flow axially rightwardly as shown
at arrow 59 axially along interior channels 106, and the balance of
the air continues radially inwardly as shown at arrow 114, and as
shown in the incorporated '700 patent in FIG. 4, and then flows
axially as shown at arrow 58. The axial ends of exterior channels
108 at the axial end of the filter element are blocked by the noted
hot melt seal bonding along adhesive strips 110. Fluid flowing
through the filter element is forced to pass from exterior channels
108 to interior channels 106. FIGS. 6 and 9 of the incorporated
'700 patent show the seal bonded adhesive 110 extending in exterior
channels 108 all the way from inner pleat tips 36 to outer pleat
tips 32 as idealized. If the seal bond does not extend all the way
from inner pleat tip 36 to outer pleat tip 32, then the shape of
the interior channel 106 at outer pleat tip 32 will generally be
more rounded and the walls of pleats 28 forming exterior channels
108 at outer pleat tips 32 will usually be closer together. In an
alternative, the adhesive seal bond in exterior channels 108 may
extend from inner pleat tips 36 only partially towards outer pleat
tips 32, and the outer portions of exterior channels 108 are
blocked at the axial end of the filter element at end cap 66.
During the molding potting process, the liquid castable material
into which the pleated filter media is dipped will foam up a short
distance axially into the channels between the pleats, as shown in
the incorporated '700 patent at inner section 116 in FIGS. 4, 8, 9
thereof, of the end cap which has migrated a distance 118, FIG. 4
of the incorporated '700 patent, between the pleats. The spacing of
glue strips 110 on the pleats from the axial ends 68 of the pleats
may be adjusted as desired in standard glue seal strip applicator
machines. Preferably, glue seal strips 110 are spaced from axial
ends 68 of the pleats by a small distance 118 to enable a slight
deformation of the axial ends 68 of the pleats by a dam in the mold
during the molding potting process, to keep the liquid castable
material of the end cap from flowing radially inwardly into inner
portions 74 of the pleat ends which are desired to be exposed,
which molding process and dam are disclosed in the noted '700
patent, and noted hereinafter. Alternatively, seal glue strips 110
may be applied at axial ends 68 of the pleats, without gap 118
therebetween.
FIG. 5 shows a mold 120 for molding or potting end cap 66 onto
pleated filter media 26 of the filter element. The mold has a
trough 122 extending along an annular first perimeter and holding
liquid castable material, such as urethane, therein into which
axial ends 68 of pleats 28 are dipped. The mold has an insert 124
with an upstanding dam 126 extending along a second annular
perimeter circumscribed by the noted annular perimeter of trough
122. Dam 126 engages axial ends 68 of the pleats between outer
pleat tips 32 and inner pleat tips 36 and impedes flow of liquid
castable material laterally radially inwardly towards inner pleat
tips 36. Trough 122 partially spans axial ends 68 of the pleats
such that the laterally outward portions 72 of the axial ends of
the pleats are covered by liquid castable material but not the
laterally inward portions 74 of the pleats, such that laterally
outward portions 72 of the axial ends 68 of the pleats are covered
by end cap 66, and the laterally inward portions 74 of the axial
ends 68 of the pleats are uncovered by end cap 66 and are left
exposed. It is preferred that the pleated filter media be dipped
into the liquid castable material in the mold by lowering the
pleated filter media downwardly until axial ends 68 of the pleats
are engaged by dam 126, and then pushing the pleated filter media
further slightly downwardly against the dam such that the dam
slightly deforms axial ends 68 of the pleats at such engagement
point which in turn pushes the pleat sidewalls forming the noted
channels slightly laterally to further block the channels and
further impede flow of liquid castable material laterally inwardly
towards inner pleat tips 36. Trough 122 is bounded by an outer
perimeter 126 and an inner perimeter 128. Outer perimeter 126 of
trough 122 is greater than outer perimeter 30 of the filter element
defined by outer pleat tips 32. Inner perimeter 128 of trough 122
is less than outer perimeter 30 of the filter element. Inner
perimeter 128 of trough 122 is greater than inner perimeter 34 of
the filter element defined by inner pleat tips 36. The noted second
perimeter of the mold at annular dam 126 is less than or equal to
inner perimeter 128 of trough 122.
As noted, the method for molding end cap 66 onto pleated filter
media 26 involves dipping axial ends 68 of the pleats into liquid
castable material in trough 122 of mold 120, and engaging axial
ends 68 of the pleats against dam 126 at a location between outer
pleat tips 32 and inner pleat tips 36 such that dam 126 impedes
flow of the liquid castable material laterally inwardly towards
inner pleat tips 36. Trough 122 is provided and aligned such that
it partially spans axial ends 68 of the pleats such that the
laterally outward portions 72 of the axial ends of the pleats are
covered by the liquid castable material during dipping, but not the
laterally inward portions 74 of the axial ends of the pleats.
Further in accordance with the described method, laterally inward
flow of the liquid castable material is impeded along the axial
ends of the pleats toward inner pleat tips 36 by providing and
aligning dam 126 to engage axial ends 68 of the pleats between
outer pleat tips 32 and inner pleat tips 36 such that laterally
outward portions 72 of the axial ends of the pleats are covered by
end cap 66, and laterally inward portions 74 of the axial ends of
the pleats are uncovered by end cap 66 and are left exposed. Trough
122 and filter element 22 are aligned during the noted dipping such
that outer perimeter 126 of trough 122 circumscribes outer
perimeter 30 of the filter element defined by outer pleat tips 32,
and inner perimeter 128 of trough 122 circumscribes inner perimeter
26 of the filter element defined by inner pleat tips 36.
FIG. 6 shows an alternate embodiment wherein outlet flow tube 90a
has an outer section 90b of reduced diameter to accommodate engine
compartment size and location requirements, yet maintaining an
increased diameter inner section 90c maintaining the increased
diameter and perimeter flow passage 56 including axial fluid flow
at 58 and the extra axial fluid flow at 59, FIGS. 2 and 6. The
spacing of axial end wall 88 of housing section 42 from axial ends
68 of the filter media pleats provides a plenum 130 accommodating
the extra flow and reducing restriction.
The described filter construction was developed for air filters,
though may be used for other fluids such as liquid. In the
disclosed embodiment, fluid to be filtered flows laterally inwardly
through the filter media from the outer perimeter to the inner
perimeter and then flows axially in the hollow interior, such that
flow passage 56 is an outlet flow passage. Alternatively, fluid to
be filtered may flow axially in hollow interior 38 and then flow
laterally outwardly through the filter media from the inner
perimeter to the outer perimeter, in which case flow passage 56 is
the inlet flow passage. In another alternative, fluid flow to or
from axial end 64 of the filter element and through the media may
be axial or a combination of axial and radial, for example as in
the noted incorporated '076 patent. In other alternatives, metal
end caps are used instead of urethane end caps, or various
combinations of materials are used for the end caps. In further
alternatives, outer section 90b, FIG. 7, of the flow tube has a
larger inner diameter than inner section 90c.
Present Invention
During further development, it has been found that there are some
applications where enhanced structural integrity is desired in the
end cap area at 66, for example wet conditions, heavy load
conditions, vibration, and the like. There are also circumstances
where cost reduction is desired. There are also circumstances where
even further sealing is desired.
FIGS. 7-11 are like FIGS. 2-6, respectively, and use like
references numerals where appropriate to facilitate understanding.
Filter element 22 is provided by pleated filter media 26 having a
plurality of pleats 28 in a closed loop having an outer perimeter
30 defined by a plurality of outer pleat tips 32, and an inner
perimeter 34 defined by a plurality of inner pleat tips 36, and
having a hollow interior 38 extending along axis 40. Fluid flows
axially in hollow interior 38 as shown at arrow 58. The filter
element has first and second axial ends 62 and 64. The first axial
end is open and provides an axial flow passage 57 therethrough
along axis 40 communicating with hollow interior 38. A resiliently
compressible end cap 200 at the open axial end covers inner and
outer pleat tips 36 and 32 and spans radially along axial ends 68
of the pleats between inner and outer perimeters 34 and 30. A flow
tube 202 communicates with hollow interior 38 and extends along
axial flow passage 57 and engages end cap 200. Flow tube 202 at
engagement 204 with end cap 200 has an inner perimeter 206 greater
than inner perimeter 34 defined by inner pleat tips 36. Inner
perimeter 206 of flow tube 202 at engagement 204 with end cap 200
is less than outer perimeter 30 defined by outer pleat tips 32.
End cap 200 has a first section 208 extending radially inwardly
from outer perimeter 30 defined by outer pleat tips 32, and has a
second section 210 extending radially outwardly from inner
perimeter 34 defined by inner pleat tips 36. First and second
sections 208 and 210 meet at a junction defining a step at 204
facing radially inwardly toward and engaging flow tube 202. The
step at 204 has a first axial length. Flow tube 202 has an inner
tubular portion 212 extending axially along step 204. Tubular
portion 212 has an inner axial end 214 facing the first axial end
of the filter element at axial ends 68 of the pleats and separated
therefrom by section 210 of end cap 200. Flow tube 202 has a flange
portion 216 extending radially from tubular portion 212 and facing
the first axial end of the filter element at axial ends 68 of the
pleats and axially spaced from inner axial end 214 of tubular
portion 212 by a second axial length which is less than the noted
first axial length, to thus provide axial compression of end cap
200 including at axial seal region 218. End cap 200 has a first
axial thickness at first section 208 at outer perimeter 30, a
second axial thickness at first section 208 at step 204, a third
axial thickness at second section 210 at step 204, and a fourth
axial thickness at second section 210 at inner perimeter 34. The
noted second axial thickness is greater than the noted third axial
thickness. The noted first axial thickness is greater than the
noted fourth axial thickness. The noted first axial thickness is
less than the noted second axial thickness. The noted third and
fourth axial thicknesses are substantially the same.
In one embodiment, the filter element includes in combination the
noted second end cap 76 at the second axial end 64 of the filter
element at axial ends 78 of the pleats and covering inner and outer
pleat tips 36 and 32 and spanning radially between inner and outer
perimeters 34 and 30, and also spanning hollow interior 38 and
closing the second axial end of the filter element. The filter
element is preferably contained in the noted housing having an end
wall 220 facing the first axial end of the filter element. Flow
tube 202 is part of end wall 220.
Flow tube 202 engages end cap 200 at first, second and third
engagement seals 218, 222 and 224, respectively, to provide triple
sealing of end cap 200 to flow tube 202. Seals 218 and 224 are
axial seals, and seal 222 is a radial seal. First inner portion 212
of flow tube 202 extends axially along step 204 and engages the
step to form the noted second radial seal 222. Tubular portion 212
has the noted inner axial end 214 axially engaging end cap 200 at
the noted second section 210 and forming the noted third axial seal
224. Flow tube 202 has the noted flange portion 216 extending
radially from tubular 212 and axially spaced outwardly of inner
axial end 214 and axially engaging end cap 200 at first section 208
and providing the noted first axial seal 218. Second radial seal
222 is axially between first and third axial seals 218 and 224.
FIG. 10 shows a mold 120 for molding or potting end cap 200 onto
pleated filter media 26 of the filter element. The mold has a
trough 122 as above. The mold has an insert 230 similar to insert
124 but with upstanding dam 232 at inner pleat tips 36 at inner
perimeter 34.
FIG. 11 shows an alternate embodiment wherein outlet flow tube 202a
has an outer section 201a of reduced diameter to accommodate engine
compartment size and location requirements, yet maintaining an
increased inner diameter section 203a, as in FIG. 6. The spacing of
axial end wall 220 of the housing from axial ends 68 of the filter
media pleats provides the noted plenum 130. End cap 200a has the
noted first and second sections 208a and 210a. End cap 200a covers
the inner and outer pleat tips 36 and 32 and spans radially between
the inner and outer perimeters 34 and 30. The end cap provides the
noted triple sealing at axial seals 218a and 224a and at radial
seal 222a.
As shown in comparing FIGS. 3, 4, 8, 9, the present construction
seals the axial ends 68 of the pleats solely with urethane end cap
200, or 200a, and eliminates reliance upon hot melt 110 for sealing
purposes. This eliminates the adhesive component in the design of
FIGS. 3, 4, and simplifies the production process, reducing cost.
In the present construction of FIGS. 8, 9, the axial ends 68 of the
pleats 28 are sealed with the same urethane 200, or 200a, used to
pot the element, rather than a combination of hot melt 110 and
urethane 66 as in FIGS. 3, 4. The present construction also
eliminates reliance upon the interface between the glue 110, the
filter media of the pleats 28, and the urethane 66 to prevent
contaminants from passing to the clean side of the filter. The
present construction further facilitates concentricity of the
closed loop configuration. The present construction further
enhances structural integrity, particularly in wet conditions,
heavy load conditions, and vibration conditions.
FIG. 12 shows a further embodiment and uses like reference numerals
from above where appropriate to facilitate understanding. End cap
200b has first section 240 extending radially inwardly from the
outer perimeter 30 defined by outer pleat tips 32, and has a second
section 242 extending radially inwardly from first section 240.
First and second sections 240 and 242 meet at a junction defining a
step 204b. Flow tube 202b communicates with hollow interior 38 and
extends along axial flow passage 57. Flow tube 202b has an inner
tubular portion 212b extending along step 204b and radially
engaging the step to form a radial seal 222 therewith. Flow tube
202b has the noted flange portion 216 extending radially outwardly
from tubular portion 212b and axially spaced from first axial end
68 of the filter element by first section 240 of end cap 200b
therebetween. Flange portion 216 engages first section 240 of end
cap 200b at engagement point 218b to form an axial seal therewith.
Tubular portion 212b has an inner axial end 244 axially facing
first end 68 of the filter element. Second section 242 of end cap
200b is axially between inner axial end 244 of tubular portion 212b
and first axial end 68 of the filter element. Second section 242 of
end cap 200b extends radially inwardly from first section 240 of
the end cap all the way to inner perimeter 34 defined by inner
pleat tips 36. End cap 200b covers inner and outer pleat tips 36
and 32 and spans radially between inner and outer perimeters 34 and
30. Inner axial end 244 of tubular portion 212b is axially spaced
from second section 242 of end cap 200b by an axial gap 246
therebetween. This may be desired in some applications to protect
against excessive axial compression or axial crushing. For example,
it may be desired to protect the pleat ends at 68 from the line of
axial force otherwise provided by the annulus at inner end 244 of
the flow tube, with or without adhesive or hot melt 110 between the
pleats.
FIG. 13 shows a further embodiment and uses like reference numerals
from above where appropriate to facilitate understanding. End cap
200c has a first section 250 extending radially inwardly from the
outer perimeter 30 defined by outer pleat tips 32, and has a second
section 252 extending radially inwardly from first section 250.
First and second sections 250 and 252 meet at a junction defining a
step 204c. Flow tube 202c communicates with hollow interior 38 and
extends along axial flow passage 57. Flow tube 202c has a tubular
portion 212c extending axially along step 204c and radially
engaging the step to form a radial seal therewith. Flow tube 202c
has flange portion 216 extending radially outwardly from tubular
portion 212c and axially spaced from first axial end 68 of the
filter element by the first section 250 of end cap 200c
therebetween. Flange portion 216 axially engages first section 250
of end cap 200c at engagement point 218c to form an axial seal
therewith. Tubular portion 212c has inner axial end 214 axially
facing first end 68 of the filter element. Second section 252 of
end cap 200c is axially between inner axial end 214 of tubular
portion 212c and first end 68 of the filter element. Second section
252 of end cap 200c extends radially inwardly from first section
250 only partially towards inner perimeter 34 defined by inner
pleat tips 36 and does not cover inner pleat tips 36. This
embodiment may be desirable in instances where the additional
migration or flow at 59 is desired. This embodiment may also be
desirable where additional flow of potting material into the pleat
ends and between the wall segments of the pleats is desired. For
example, the wider the radial extent of the end cap along axial end
68 of the filter element, the greater the axially leftward
migration of the molten potting material into and between the
pleats. This may be desirable for enhanced sealing including
greater interface area with the adhesive or hot melt 110 between
the pleats. Inner axial end 214 of tubular portion 212c may axially
engage second section 252 of end cap 200c as shown in FIG. 13 to
form a second axial seal 224 therewith as in FIG. 7. Alternatively,
inner axial end 214 may be spaced axially rightwardly of second
section 252 of the end cap by an axial gap therebetween as at axial
gap 246 in FIG. 12.
FIG. 14 shows a further embodiment including a filter element 260
including a closed loop filter media member 262 having a hollow
interior 264 extending along a given axis 266, and which may also
include an outer prefilter member 268 such as open cell foam. Fluid
flows axially in hollow interior 264. The filter element has first
and second axial ends 270 and 271. First axial end 270 is open and
provides an axial flow passage 272 therethrough along axis 266
communicating with hollow interior 264. A resiliently compressible
end cap 274 is provided at first axial end 270. A flow tube as
shown in dashed line at 276 and which is comparable to flow tube
202, communicates with hollow interior 264 and extends along axial
flow passage 272. Flow tube 276 has a tubular portion 278,
comparable to tubular portion 212, engaging end cap 274 and forming
a seal therewith, comparable to seal 218 and/or 222 and/or 224.
Tubular portion 278 is cylindrical. Filter media member 262 is
non-cylindrical. In one embodiment, the filter media member is
elliptical, such as oval, racetrack shaped, or the like. End cap
274 has a first section 280 extending radially inwardly from an
outer perimeter 282, and has second section 284 extending radially
inwardly from first section 280 to an inner perimeter 286. First
and second sections 280 and 284 are comparable to first and second
sections 240 and 242 and to first and second sections 250 and 252.
First and second sections 280 and 284 meet at a junction defining a
step 288, comparable to steps 204, 204b, 204c. First section 280
has the noted outer perimeter 282, and has an inner perimeter 290
at step 288. Second section 284 has an outer perimeter 292 at step
288, and has the noted inner perimeter 286 communicating with
hollow interior 264. Outer perimeter 282 of first section 280 is
non-cylindrical. Inner perimeter 290 of first section 280 is
cylindrical. Step 288 is cylindrical. Outer perimeter 292 of second
section 284 is cylindrical. Cylindrical tubular portion 278 engages
end cap 274 at cylindrical step 288, comparable to the above noted
engagement of cylindrical portions 212, 212b, 212c with steps 204,
204b, 204c. Inner perimeter 286 of second section 284 is
non-cylindrical. Filter media member 262 and outer perimeter 282 of
first section 280 of end cap 274 are elliptical and have a radially
extending major axis (left-right in FIG. 14), and a radially
extending minor axis (up/down in FIG. 14). The radial extension of
first section 280 of end cap 274 along the major axis between outer
perimeter 282 of first section 280 of end cap 274 and step 290 is
greater than the radial extension of first section 280 of end cap
274 along the minor axis between outer perimeter 282 of first
section 280 of end cap 274 and step 288. The radial extension of
second section 284 of end cap 274 along the minor axis between step
288 and inner perimeter 286 of second section 284 of end cap 274 is
greater than the radial extension of the second section 284 of end
cap 274 along the major axis between step 288 and inner perimeter
286 of second section 284 of end cap 274. In the embodiment shown,
filter media member 262 is provided by pleated filter media having
a plurality of pleats as above in a closed loop having an outer
perimeter defined by a plurality of outer pleat tips, comparable to
pleat tips 32, and an inner perimeter defined by a plurality of
inner pleat tips, comparable to pleat tips 36, the loop having the
noted hollow interior 264 extending along the noted given axis 266.
Other types of filter media may be used, including non-pleated
media. The disclosed elliptical filter design may be used in
implementations where it is desired to have an elliptical filter
and to maximize the inlet or outlet diameter of the filter or match
specifications requiring cylindrical inlet or outlet flow
tubes.
It is recognized that various equivalents, alternatives and
modifications are possible within the scope of the appended
claims.
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