U.S. patent application number 11/939060 was filed with the patent office on 2008-10-09 for exhaust filter.
This patent application is currently assigned to DONALDSON COMPANY, INC.. Invention is credited to Steve Anderson, John Belisle, Jared Blaisdell, John Herman, John Hiemstra, Gary D. Reeves, Wayne M. Wagner.
Application Number | 20080245039 11/939060 |
Document ID | / |
Family ID | 34590154 |
Filed Date | 2008-10-09 |
United States Patent
Application |
20080245039 |
Kind Code |
A1 |
Anderson; Steve ; et
al. |
October 9, 2008 |
Exhaust Filter
Abstract
An exhaust filter having a pleated filter media mounted between
end caps is disclosed herein. The filter has a construction
suitable for high temperature environments such as engine exhaust
systems.
Inventors: |
Anderson; Steve; (Stevens
Point, WI) ; Blaisdell; Jared; (Bloomington, MN)
; Belisle; John; (Hampton, MN) ; Herman; John;
(Rhinelander, WI) ; Hiemstra; John; (Lakeville,
MN) ; Reeves; Gary D.; (Lakeville, MN) ;
Wagner; Wayne M.; (Apple Valley, MN) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
DONALDSON COMPANY, INC.
Bloomington
MN
|
Family ID: |
34590154 |
Appl. No.: |
11/939060 |
Filed: |
November 13, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10978686 |
Nov 1, 2004 |
7294162 |
|
|
11939060 |
|
|
|
|
60517363 |
Nov 4, 2003 |
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Current U.S.
Class: |
55/498 |
Current CPC
Class: |
F01N 3/0226 20130101;
B01D 46/521 20130101; Y02T 10/20 20130101; B01D 2271/022 20130101;
F01N 2310/06 20130101; B01D 46/2414 20130101; F01N 2310/14
20130101; F01N 3/2867 20130101; F01N 2330/102 20130101; B01D
2265/04 20130101; F01N 2450/18 20130101; Y02T 10/12 20130101; F01N
2450/22 20130101; F01N 3/0215 20130101; F01N 2510/08 20130101 |
Class at
Publication: |
55/498 |
International
Class: |
B01D 46/02 20060101
B01D046/02 |
Claims
1. An exhaust filter comprising: a pleated filter element having
first and second ends; a first end cap mounted at the first end of
the filter element and a second end cap mounted at the second end
of the filter element; a sealing gasket provided at the first end
cap; and the filter element, the first and second end caps and the
sealing gasket each being constructed of a material that does not
generate harmful levels of off-gasses when exposed to continuous
operating temperatures that exceed 500.degree. F.
2. The filter of claim 1, wherein the end caps include aluminized
steel.
3. The filter of claim 1, wherein the filter element includes a
fibrous construction.
4. The filter of claim 3, wherein the filter element includes glass
fibers.
5. The filter element of claim 3, wherein the filter element
includes ceramic fibers.
6. The filter of claim 1, wherein the filter element includes a
filter material laminated to a mesh.
7. The filter of claim 6, wherein the filter material is laminated
between two meshes.
8. The filter of claim 6, wherein the mesh is coated with a
protective layer for withstanding continuous operating temperatures
that exceed 500.degree. F.
9. The filter of claim 8, wherein the protective layer includes an
aluminum paste.
10. The filter of claim 8, wherein the mesh includes steel and
copper, and wherein the protective layer is adapted to isolate the
copper from an exhaust stream.
11-22. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation of U.S. patent
application Ser. No. 10/978,686 filed Nov. 1, 2004, now U.S. Pat.
No. 7,294,162, which claims the benefit of U.S. Provisional Patent
Application Ser. No. 60/517,363 filed Nov. 4, 2003, which
applications are hereby incorporated by reference in their
entirety.
TECHNICAL FIELD
[0002] The present invention relates generally to air filters. More
particularly, the present invention relates to air filters for use
in exhaust systems.
BACKGROUND
[0003] Engine exhaust filters can have a variety of constructions.
One type of exhaust filter includes a cellular ceramic core
defining a honeycomb of channels having plugged ends. Filters
having this construction are disclosed in U.S. Pat. Nos. 4,276,071
and 4,851,015. Other exhaust filters include a filter media defined
by a plug of wire mesh. Filters having this construction are
disclosed in U.S. Pat. Nos. 3,499,269 and 4,902,487. Filters of the
type indicated above can be catalyzed or un-catalyzed. Un-catalyzed
filters require high temperatures to be efficiently regenerated.
Catalyzed filters can be regenerated at lower temperatures, but can
generate undesirable by-products such as NO.sub.2.
[0004] Filters are also often used to filter the intake air drawn
into an engine. U.S. Pat. Nos. 3,078,650 and 5,547,480 disclose air
filters of the type used with the intake systems of engines. These
filters include cylindrical pleated filter elements mounted within
housings. The filter elements define hollow interiors, and the air
being filtered travels radially through the pleated filter
elements. While suitable for engine intake applications, these
types of filters are not adapted for the high temperature
environment created by engine exhaust.
[0005] Engine emission regulations have become increasingly
stringent. What are needed are alternative filtration systems for
use in reducing engine exhaust emissions.
SUMMARY
[0006] One aspect of the present invention relates to an air filter
having a design suitable for the air filter to be used in a
relatively high temperature environment such as an engine exhaust
system. In one embodiment, the air filter includes a cylindrical,
pleated filter element
[0007] Examples of a variety of inventive aspects in addition to
those described above are set forth in the description that
follows. It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are not restrictive of the broad inventive
aspects that underline the examples disclosed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 schematically shows an example system in which
filters in accordance with the principles of the present disclosure
may be utilized;
[0009] FIG. 2 is a cut away view of an air filter having features
that are examples of inventive aspects in accordance with the
principles of the present disclosure;
[0010] FIG. 3 is an end view of the air filter of FIG. 2;
[0011] FIG. 4 is a cross sectional view through a portion of the
filter media of the air filter of FIG. 2;
[0012] FIG. 5 illustrates a portion of FIG. 2 in enlarged
detail;
[0013] FIG. 6 illustrates another filter element having features
that are examples of inventive aspects in accordance with the
principles of the present disclosure;
[0014] FIG. 7 is an enlarged detailed cross-sectional view of a
portion of FIG. 6;
[0015] FIG. 8 illustrates a filter media of the embodiment of FIG.
6 prior to folding the axial extensions to form an end sealing
structure;
[0016] FIG. 9 illustrates the filter media of FIG. 8 after the
axial extensions have been folded to form an end sealing
structure;
[0017] FIG. 10 shows an end cap having features that are examples
of inventive aspects in accordance with the principles of the
present disclosure;
[0018] FIG. 11 shows another end cap having features that are
examples of inventive aspects in accordance with the principles of
the present disclosure;
[0019] FIG. 12 shows a further end cap having features that are
examples of inventive aspects in accordance with the principles of
the present disclosure;
[0020] FIG. 13 is a plan view of the end cap of FIG. 10 with a clip
being used to secure a gasket thereto;
[0021] FIG. 14 is a cross-sectional view taken along section line
14-14;
[0022] FIG. 15 is a plan view of the clip of FIGS. 13 and 14 in a
precursor state;
[0023] FIG. 16 is a side view of the clip of FIGS. 13 and 14 prior
to being roller into a ring shape;
[0024] FIG. 17 is a top view of FIG. 16; and
[0025] FIG. 18 is an end view of FIG; 16.
DETAILED DESCRIPTION
[0026] FIG. 1 schematically illustrates an engine 20 having an
intake system 22 and an exhaust system 24. An air filter 26 can be
provided as part of the intake system 22 to remove particles from
the air drawn into the engine 20. An air filter 28 in accordance
with the principles of the present disclosure can be provided at
the exhaust system 24 for removing volatile particulates as well as
non-volatile particulates such as carbon-based particulates (e.g.,
soot) from the exhaust stream. In certain embodiments, the engine
20 can be a diesel engine such as the type used in motor vehicles
such as forklifts, skid steer loaders, mining equipment, or other
motor vehicles or equipment. It will be appreciated that the
exhaust stream generated by the engine 20 can often have a
relatively high temperature. For example, temperatures exceeding
600.degree. F. are not uncommon. Therefore, it is preferred for the
air filter 28 to have a construction suitable for operating in a
relatively high temperature environment.
[0027] A. Example Filter Assembly
[0028] FIGS. 2 and 3 illustrate an air filter 28 having features
that are examples of inventive aspects in accordance with the
principles of the present disclosure. The air filter 28 includes a
generally cylindrical filter media 30 mounted between end caps 32.
The ends of the filter media 30 can be sealed and secured to the
end caps 32 by a potting material 34. Sealing gaskets 36 are
provided on axially outwardly facing surfaces of the end caps 32. A
cylindrical shell 38 preferably is mounted about the exterior of
the filter media 30. The shell 38 defines openings for allowing the
passage of air through the shell. Ends of the shell 38 are secured
(e.g., welded) to the end caps 32 such that the entire assembly of
parts is secured together as a unit. In certain embodiments, the
top and bottom ends of the shell can include solid borders/bands to
facilitate attaching the end caps thereto. In other embodiments,
the end caps can be connected together by metal strips that extend
along the exterior of the shell between the end caps such that the
shell and filter media are captured between the end caps. It will
be appreciated that various components of the air filter 28 are
designed to withstand relatively high temperatures such as those
generated by an exhaust stream. In certain embodiments, the shell
38 can be perforated metal or expanded metal. In other embodiments,
the filter and shell can have other shapes such as a conical
shape.
[0029] As depicted in FIG. 2, the air filter 28 has a hollow core
40. The end caps 32 define central openings 41 in axial alignment
with the hollow core 40. In this embodiment, dirty air from an
exhaust system is directed into the hollow core 40 through the
central opening 41 of one of the end caps 32. From within the
hollow core 40, the air is forced radially outwardly through the
filter media 30 and the shell 38 to the atmosphere. This type of
embodiment is a reverse-flow filter, since flow proceeds from
inside the filter element radially outwardly through the filter
element. In alternative embodiments, the filter unit can be
provided with a reinforcing core (e.g., a perforated metal core or
an expanded metal core) within the filter element, and flow can
proceed from outside the filter element radially inwardly through
the filter element into the interior of the core. Further, while
the embodiment of FIG. 2 has two open-ended caps, in alternative
embodiments at least one of the end caps may be closed.
[0030] In use, the filter 28 can be mounted to an exhaust pipe for
conveying an exhaust stream away from an engine. For example, the
filter 28 can be mounted within a filter housing secured (e.g.,
clamped) to the end of an exhaust pipe. When mounted within the
housing, one of the gaskets forms a seal with the housing, while
the other gasket forms a seal with a mounting plate that is clamped
or otherwise fastened to the housing to firmly secure the filter 28
within the housing. For single gasket embodiments (e.g.,
embodiments with one of the end caps closed), other filter housing
constructions will be used. It will be appreciated that a large
number of techniques for mounting filters within air streams are
known, and that all of the various techniques are within the scope
of the present invention.
[0031] B. Example Filter Media
[0032] The filter media 30 preferably has a construction suitable
for high temperature applications such as exhaust systems. In one
embodiment, the filter media 30 is constructed to not generate
harmful levels of off-gasses when exposed to continuous operating
temperatures equal to or greater than 500.degree. F. In another
embodiment, the filter media 30 is constructed to not generate
harmful levels of off-gasses when exposed to continuous operating
temperatures that exceed 650.degree. F. In certain other
embodiments, the filter media is constructed of a material that
does not generate harmful levels of off-gasses when exposed to
temperatures excursions equal to or greater than 800.degree. F., or
equal to or greater than 900.degree. F. As defined herein, harmful
levels of off-gasses include levels of harmful off-gasses that that
exceed permissible regulatory limits.
[0033] In one embodiment, the filter media 30 is folded into a
pleated configuration, and rolled into a cylinder (see FIG. 3). As
shown in FIG. 4, the filter media 30 has a laminated construction
with a layer of filter material 50 secured between two layers of
reinforcing material or scrim such as mesh screen 51 or expanded
metal. In certain embodiments, the filter media includes a layer
fibers (e.g., glass or ceramic fibers). The layer can include woven
or non-woven (e.g., matted) fibers. An example material includes a
fiberglass filter material is sold by Filtration Specialties Inc.
under the name Dynaglas.RTM. 2201. Other materials capable of
withstanding relatively high temperatures, whether fibrous or
non-fibrous, can also be used. In other embodiments, the media can
be supported by a single reinforcing layer rather than being
sandwiched between two reinforcing layers.
[0034] In certain embodiments, the screen 51 can include a mesh
coated with a protective layer. The mesh can be manufactured of a
metal material such as metal wire. In one embodiment, the metal
material can include steel with a residual outer layer of copper.
The protective layer provides a number of functions. First, the
layer is preferably capable of withstanding temperatures comparable
to those specified with respect to the filter media. The protective
layer resists corrosion of the screen 51. In embodiments where the
material of the screen includes copper, the protective layer
isolates the copper from the exhaust stream to prevent the copper
from reacting with sulfur in the exhaust stream and generating
copper sulfate. An example protective layer includes an aluminum
paint material or an epoxy coating.
[0035] C. Example End Caps and Outer Shell
[0036] Components such as end caps, cores or shells used in filters
in accordance with the present disclosure preferably have a
construction adapted to resist degradation/deterioration when
exposed to high temperatures such as those present in the exhaust
stream of an engine. In certain embodiments, the components are
constructed of a material that does not generate harmful levels of
off-gasses when exposed to continuous operating temperatures equal
to or greater than 500.degree. F. In certain other embodiments, the
components are constructed of a material that does not generate
harmful levels of off-gasses when exposed to continuous operating
temperatures equal to or greater than 650.degree. F. In certain
other embodiments, the components are constructed of a material
that does not generate harmful levels of off-gasses when exposed to
temperatures excursions equal to or greater than 800.degree. F., or
equal to or greater than 900.degree. F. In a preferred embodiment
some or all of the components have an aluminized steel
construction.
[0037] D. Example Gasket
[0038] The gaskets 36 preferably have a construction suitable for
high temperature applications such as exhaust systems. In certain
embodiments, the gaskets are constructed of a material that does
not generate harmful levels of off-gasses when exposed to
continuous operating temperatures equal to or greater than
500.degree. F. In certain other embodiments, the gaskets are
constructed of a material that does not generate harmful levels of
off-gasses when exposed to continuous operating temperatures equal
to or greater than 650.degree. F. In certain other embodiments, the
gaskets are constructed of a material that does not generate
harmful levels of off-gasses when exposed to temperature excursions
equal to or greater than 800.degree. F., or equal to or greater
than 900.degree. F.
[0039] In one embodiment, the gaskets 36 are formed by a generally
flat sheet of fabric material provided in a ring shape that
surrounds the central openings 41 of the end caps 32 (see FIG. 3).
The fabric can have fibers arranged in a woven or non-woven (e.g.,
matted) construction. The gaskets can include a glass fiber
construction, a ceramic fiber construction, a basalt fiber
construction, or other fibrous constructions capable of
withstanding the relatively high temperatures environments. In one
particular embodiment, the gaskets can include a fiberglass mat
laminated to fiberglass cloth. In certain embodiments, the gaskets
36 each have a generally rectangular cross-sectional profile (see
FIG. 2). In one embodiment, the gaskets can include chopped "E"
glass fibers having a nominal fiber diameter of 0.00036 inches
needled into the mat without a resin binder. Example thicknesses of
the gaskets are in the range of 0.1-1.0 inches. While fibrous
gaskets are preferred, non-fibrous gaskets capable of withstanding
relatively high temperature environments could also be used.
[0040] In a preferred embodiment, the gaskets 36 are secured to the
end caps 32 by a mechanical fastening technique. For example, the
gaskets can be secured to the end caps 32 by structures such as
pins, clips, screws, bolts, flanges, rivets, hooks, catches, barbs,
clamps or other fastening techniques. As shown in FIGS. 2, 3 and 5,
the gaskets 36 are secured to the end caps 32 by staples 60 that
are uniformly spaced about the circumference of the gaskets 36. The
staples 60 are shown driven through the gaskets 36 and end caps 32,
and into the potting material. In one embodiment, the staples are
galvanized coated.
[0041] E. Example Potting Material
[0042] Potting material used in filters in accordance with the
present disclosure preferably has a construction adapted to resist
degradation/deterioration when exposed to high temperatures such as
those present in the exhaust stream of an engine. In certain
embodiments, the potting material is constructed of a material that
does not generate harmful levels of off-gasses when exposed to
continuous operating temperatures equal to or greater than
500.degree. F. In certain other embodiments, the potting material
is constructed of a material that does not generate harmful levels
of off-gasses when exposed to continuous operating temperatures
equal to or greater than 650.degree. F. In certain other
embodiments, the potting material is constructed of a material that
does not generate harmful levels of off-gasses when exposed to
temperatures excursions equal to or greater than 800.degree. F., or
equal to or greater than 900.degree. F. In one embodiment, the
potting material includes a silicone material. In another
embodiment, the potting material can be replaced with a fabric
layer compressed between the end caps and the ends of the filter
media. The fabric layer can have a construction like the fibrous
materials identified with respect to the gaskets.
[0043] FIG. 6 shows an alternative filter 128 having a filter media
130 mounted between end caps 132. Seals can be provided between the
end caps 132 and the ends of the filter media 130 by folding axial
extensions 180 of the filter media 130 over the axial ends of the
pleated filter media 130 (as shown at FIG. 7), such that the folded
extensions overlap to fully cover the ends of the filter media. The
axial extensions 180 can be held in place at the ends of the filter
media by fastening or otherwise securing the end caps 132 to a
shell (e.g., a shell similar to shell 38 of FIG. 2) such that the
extensions of the filter media are fixed in place via compression
from the end caps 132. In embodiments where the filter medias
includes a backing/reinforcing material such a screen 51, the
screen 51 preferably extends only to the axial ends 181 of the
pleated filter media 130 (as shown in FIG. 8) such that the screen
51 is not present in the folded axial extensions 180 of the filter
media. To manufacture the filter 128, the media 130 is pleated as
shown at FIG. 8. The extensions 180 are then folded over onto
adjacent pleats in a fan-like manner to completely cover the ends
of the filter media 130 as shown at FIG. 9. The end caps 132 are
then mounted over the ends of the filter media 130 with the folded
over extensions 180 lining the interior of the caps 132. A shell is
then mounted about the exterior of the filter media 130 and end
caps 132 are secured to the ends of the shell to hold the assembly
together as one unit.
[0044] In alternative embodiments, other more rigid materials can
be used as potting materials. For example, in one embodiment, a
ceramic potting compound can be used. In use, the ceramic is
applied to the interior of the end caps in a liquid or paste form.
The ends of the filter media are then inserted into and embedded in
the ceramic within the end caps. The ceramic is then allowed to
cure and thus harden within the end caps. After hardening, the
ceramic does not adhere well to the metal end caps any may have a
tendency to fall out. Therefore, the end caps are preferably
provided with structure for retaining the ceramic therein after
hardening.
[0045] FIG. 10 shows an end cap 232 having dimples 290 that project
into ceramic potting 291 within the end cap 232 to prevent the
ceramic potting 291 from dislodging from the end cap 232. FIG. 11
shows an end cap 332 having tapered walls 393 for retaining ceramic
potting 391 within the end cap 332. The walls 393 converge as the
walls extend from a closed end to an open end of the end cap 332.
FIG. 12 shows an end cap 432 having walls 493 for retaining ceramic
potting 491 within the end cap 432.
[0046] Referring to FIGS. 13 and 14, the end cap 232 is shown with
a clip 270 being used to retain a fibrous annular gasket 236 at the
outer end surface 237 of the end cap 232. The clip 270 includes a
ring portion 272 that forms a main body of the clip 270. The ring
portion extends through the central holes of the end cap 232 and
the gasket 236. The clip 270 also includes gasket retention fingers
274 that project radially outwardly from the upper edge of the ring
portion 272. The fingers 274 overlap the gasket 236 and compress
the gasket 236 against the outer end surface 237 of the end cap
232. Mechanical retention tabs 276 are provided at the lower edge
of the ring portion 272. The tabs 276 provide a mechanical
interlock (e.g., a snap-fit) with the interior of the end cap 232.
In other embodiments, the clip 270 could be welded (e.g., spot
welded) to the end cap 232.
[0047] In one embodiment, the clip 270 can be made by stamping the
clip from a sheet of metal. A flat, precursor clip 270a stamped
from a sheet of metal is shown at FIG. 15. After stamping the
precursor clip 270a, the fingers 274 and the tabs 276 are bent as
shown at FIGS. 16-18. The main body is then curled in a circle, and
ends 280 of the main body are attached together (e.g., by
fasteners, welding a mechanical interlock, etc.) to complete the
manufacturing process.
[0048] The above specification, examples and data provide a
complete description of the manufacture and use of the composition
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.
* * * * *