U.S. patent application number 10/084769 was filed with the patent office on 2002-10-03 for liquid filter construction and methods.
This patent application is currently assigned to Donaldson Company, Inc.. Invention is credited to Hacker, John R., Harder, David B., Kiral, Gerald D., Socha, Kevin K., Stenersen, Eivind, Streitmatter, Ronald W..
Application Number | 20020139735 10/084769 |
Document ID | / |
Family ID | 26923216 |
Filed Date | 2002-10-03 |
United States Patent
Application |
20020139735 |
Kind Code |
A1 |
Stenersen, Eivind ; et
al. |
October 3, 2002 |
Liquid filter construction and methods
Abstract
Liquid filter constructions include a baffle plate secured to a
can, by way of laser welding. A filter element is operably oriented
within the interior of the can. The filter element includes a first
end cap and a media pack secured to the first end cap. In some
embodiments, the first end cap radially abuts an outer, annular
surface of a tubular member of the baffle plate to form a radially
directed seal between the first end cap and the tubular member.
Liquid filter constructions of this type have a burst strength
between 500-800 psi (about 3.4-5.5 MPa), along a longitudinal
section of the can wall. Constructions of this type eliminate a
roll or lock seam, an inner gasket, an inner compressive spring,
and a gasket retainer. Systems for using liquid filters are
described herein. Methods of constructing and using these types of
filter arrangements are also described.
Inventors: |
Stenersen, Eivind; (River
Falls, WI) ; Harder, David B.; (Burnsville, MN)
; Hacker, John R.; (Bloomington, MN) ; Kiral,
Gerald D.; (Bloomington, MN) ; Streitmatter, Ronald
W.; (Champaign, IL) ; Socha, Kevin K.;
(Peoria, IL) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
Donaldson Company, Inc.
Minneapolis
MN
|
Family ID: |
26923216 |
Appl. No.: |
10/084769 |
Filed: |
February 25, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10084769 |
Feb 25, 2002 |
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09653653 |
Sep 1, 2000 |
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6384369 |
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60229348 |
Sep 22, 1999 |
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Current U.S.
Class: |
210/167.02 |
Current CPC
Class: |
B01D 27/103 20130101;
B01D 27/005 20130101; B01D 2201/4046 20130101; B01D 2201/291
20130101; B01D 27/08 20130101; B01D 2201/304 20130101; B01D
2201/302 20130101 |
Class at
Publication: |
210/168 |
International
Class: |
F01M 001/00 |
Claims
We claim:
1. A liquid filter construction comprising: (a) a metal baffle
plate having an inlet arrangement and an outlet arrangement; (i)
said metal baffle plate having an average cross-sectional thickness
of at least 0.080 inch; (b) a metal can having an interior and an
average cross-sectional wall thickness different than that of said
metal baffle plate thickness; said metal can average
cross-sectional wall thickness being at least 0.008 inch; (i) said
metal can being secured to said steel baffle plate along a laser
welded seam; and (c) a filter element operably oriented within said
interior of said metal can.
2. A liquid filter construction according to claim 1 wherein: (a)
one of said inlet arrangement and said outlet arrangement defines a
tubular member having an outer, annular surface; and (b) said
filter element includes at least a first end cap and a media pack
secured to said first end cap.
3. A liquid filter construction according to claim 2 further
comprising: (a) a radially directed seal between said first end cap
and said outer, annular surface of said tubular member.
4. A liquid filter construction according to claim 3 wherein: (a)
said baffle plate includes an inner surface oriented within said
can interior, and an opposite outer surface remote from said can
interior; (i) said baffle plate including a channel in said outer
surface constructed and arranged to hold a seal member.
5. A liquid filter construction according to claim 4 wherein: (a)
said first end cap includes a plurality of axially extending
protrusions engaging said inner surface of said baffle plate; and
(b) said first end cap radially abuts said outer, annular surface
of said tubular member to form said radially directed seal.
6. A liquid filter construction according to claim 5 wherein: (a)
said filter element further includes a second end cap and an inner
liner; (i) said media pack extending between said first end cap and
said second end cap (ii) said media pack circumscribing said inner
liner.
7. A liquid filter construction according to claim 6 further
including: (a) a rigid structural member oriented in said can
interior; (i) said rigid structural member abutting an end of said
can remote from said baffle plate and supporting said filter
element.
8. A liquid filter construction according to claim 7 wherein: (a)
said rigid structural member is secured to said second end cap.
9. A liquid filter construction according to claim 7 wherein: (a)
said rigid structural member is an integral part of said inner
liner.
10. A liquid filter construction according to claim 7 wherein: (a)
said rigid structural member comprises a bypass valve assembly.
11. A liquid filter construction according to claim 6 wherein: (a)
said second end cap includes a plurality of radially directed
protrusions engaging an inner portion of said can.
12. A liquid filter construction according to claim 6 wherein: (a)
said media pack comprises pleated paper potted within said first
and second end caps; (b) said first and second end caps comprise
urethane or acrylic; and (c) said inner liner comprises a rigid,
plastic material.
13. A liquid filter construction according to claim 1 wherein: (a)
said baffle plate is steel and has an average cross-sectional
thickness of no greater than 3.0 in.; (b) said can is steel and has
an average cross-sectional wall thickness of no greater than 0.048
in.
14. A liquid filter construction according to claim 13 wherein: (a)
said baffle plate has an outer annular surface; (i) said laser
welded seam being between said can and said outer annular surface
of said baffle plate.
15. A liquid filter construction according to claim 1 wherein: (a)
said filter element is sealed against said baffle plate by an
axially directed seal.
16. A filtration system comprising: (a) an engine having a size of
at least 10 hp and a lubrication system; and (b) a filter
construction operably mounted to clean liquid flowing in said
lubrication system; said filter construction including: (i) a metal
can having an interior and a first average cross-sectional wall
thickness; (ii) a metal baffle plate having an inlet oriented to
take in liquid to be cleaned for said lubrication system and an
outlet oriented to exhaust cleaned liquid; (A) said metal baffle
plate having a second average cross-sectional thickness; the second
average cross-sectional wall thickness being at least 200% of the
first average cross-sectional wall thickness; (B) said metal can
being secured to said metal baffle plate along a laser welded seam;
and (iii) a filter element operably oriented within said interior
of said metal can.
17. A filtration system according to claim 16 wherein: (a) said
lubrication system is constructed and arranged to operate at
pressures no greater than about 200 psi.
18. A filtration system according to claim 16 wherein: (a) said
filter element having at least a first end cap and a media pack
secured to said first end cap; (i) said first end cap radially
abutting said outer, annular surface of said tubular member to form
a radially directed seal between said first end cap and said
tubular member.
19. A method of constructing a filter; the method comprising: (a)
inserting a filter element into a metal can; the metal can having
at least one open end and a first average cross-sectional wall
thickness; (b) covering the one open end with a metal baffle plate;
the baffle plate having a second average cross-sectional thickness;
(i) the second average cross-sectional thickness being at least
200% of the first average cross-sectional wall thickness; and (c)
securing the baffle plate to the can by laser welding.
20. A method according to claim 19 wherein: (a) said step of
securing includes laser welding at least first and second, spaced
tacks between the baffle plate and the can and then laser welding
at least a 360.degree. seam between the baffle plate and the can;
(i) the first average cross-sectional wall thickness of the can
being at least 0.008 inch; and (ii) the second average
cross-sectional wall thickness of the baffle plate being at least
about 0.08 inch.
21. A method according to claim 19 wherein: (a) said step of
securing includes laser welding at least first and second, spaced
tacks between the baffle plate and the can; the first and second
tacks being spaced about 160.degree.-200.degree. apart.
22. A method according to claim 19 further including: (a)
assembling the filter element by: (i) securing a tubular
construction of filtering media between first and second opposite
end caps; the first end cap having an inner, annular surface
defining a first opening; and (ii) pressing a rigid structural
member into the second end cap; (b) inserting a neck of the baffle
plate into the first opening and forming a radially directed seal
between the neck and the first end cap; (c) wherein said step of
inserting includes placing the filter element in the can, until the
rigid structural member abuts an end of the can; and (d) wherein
said step of covering includes engaging the baffle plate against
the first end cap.
23. A method according to claim 19 wherein: (a) said step of
securing includes laser welding at a speed of at least 400
inches/minute.
Description
FIELD OF THE INVENTION
[0001] This disclosure relates to fluid filters including their
construction and use. In particular, this disclosure concerns
liquid filters to clean contaminants from fluid systems such as
engine and transmission lubrication systems, engine fuel systems,
and hydraulic systems.
BACKGROUND
[0002] Certain types of fluid filters, for example oil or lube
filters, fuel filters, or hydraulic fluid filters, operate to
remove substantial amounts of particulate material from liquid
flow, typically in a circulating environment.
[0003] Such filters generally include a filter element within a
drawn, relatively thin, cylindrical metal housing and a stamped
metal baffle or cover plate at the open end of the housing.
Typically, there is a gasket retainer projection welded to the
cover plate, and the gasket retainer is secured to the housing by a
roll or lock seam. A central threaded opening is provided in the
cover plate for spinning the filter onto a threaded stud of a
mounting base or filter head.
[0004] Fluid filters of this type can be mathematically modeled to
approximate pressure vessel systems. A typical pressure vessel
system is mainly subject to two types of stresses--hoop stress and
longitudinal stress. Hoop stress is calculated by multiplying the
internal pressure times the radius and dividing that product by the
wall thickness of the vessel. The hoop stress acts tangent to the
surface of the pressure vessel. The longitudinal stress is the
stress produced at right angles to the hoop stress (i.e., parallel
to the longitudinal axis of the pressure vessel.) The longitudinal
stress is calculated by multiplying the internal pressure times the
radius and dividing that product by two times the wall
thickness.
[0005] The longitudinal stress is one-half of the value of the hoop
stress. In theoretically exact pressure vessel systems, when the
pressure in the pressure vessel is raised to the bursting point,
failure should occur along a longitudinal seam of the pressure
vessel. In other words, this means that the system is optimized for
burst strength if the failure point occurs at the longitudinal
stress point. If, under a burst test, the system fails at some
point other than along a longitudinal seam, this means that,
theoretically, the system has not been optimized for strength.
[0006] In previous existing filters having a rolled lock joint
connection between the gasket retainer and the housing, as pressure
is increased to the point of mechanical failure, the failure
typically occurs at the rolled lock joint. This failure point is
often at pressures lower than the pressure point at which the
pressure vessel should fail along a longitudinal seam.
[0007] In addition, in previous existing filters having a rolled
lock joint connection between the gasket retainer and the housing,
there are other problems as well. As discussed above, the baffle
plate or cover is typically connected to the gasket retainer with
projection welds. Sometimes, the projection welds can break due to
vibration or pressure pulses. When the projection welds break, the
filter cannot be spun off from the filter head.
[0008] Improvements in these types of filter systems are
desirable.
SUMMARY OF THE DISCLOSURE
[0009] In one aspect, the disclosure describes a liquid filter
construction including a cover plate or baffle plate attached to a
can with a filter element operably oriented within an interior of
the can. The baffle plate, in preferred constructions, will be
metal, preferably steel, with an average cross-sectional thickness
of at least about 0.080 inch (about 2 mm). In preferred
constructions, the can will be metal, preferably steel, and will
have an average cross-sectional wall thickness that is different
from the thickness of the baffle plate, and is at least about 0.008
inch (about 0.2 mm). In certain arrangements, the baffle plate will
be at least 200% of the thickness of the can. Preferably, the can
will be secured to the baffle plate along a laser welded seam.
[0010] In preferred constructions, the filter element will include
at least a first end cap and a media pack secured to the first end
cap. The first end cap will radially abut an outer, annular surface
of a tubular member forming either the inlet or outlet to formal a
radially directed seal between the first end cap and the tubular
member.
[0011] Filtration systems are disclosed that utilize liquid filter
constructions as characterized herein. Filtration systems may
comprise lubrication systems, fuel systems, or hydraulic systems.
Such systems typically operate at pressures of no greater than
about 200 psi (about 1.4 MPa) for lubrication systems and fuel
systems. Hydraulic systems may be higher.
[0012] Methods for filtering liquid are disclosed and preferably
utilize constructions and systems as characterized herein.
[0013] Methods of constructing a filter are also disclosed.
Preferred methods will include laser welding a can to a baffle
plate, wherein the can and baffle plate have dissimilar
thicknesses.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic view of a typical system employing
liquid filters, constructed according to principles of this
disclosure;
[0015] FIG. 2 is a schematic, front elevational view of one
embodiment of a liquid filter cartridge mounted on a filter head,
constructed according to principles of this disclosure;
[0016] FIG. 3 is a schematic, cross-sectional view of the filter
cartridge of FIG. 2 taken along the line 3-3 of FIG. 2;
[0017] FIG. 4 is a schematic, cross-sectional view analogous to the
view depicted in FIG. 3 and depicting an alternative embodiment of
a filter cartridge;
[0018] FIG. 5 is an exploded, perspective view of the liquid filter
cartridge depicted in FIG. 4;
[0019] FIG. 6 is a schematic, cross-sectional view analogous to the
views shown in FIGS. 3 and 4 and showing another embodiment of a
filter cartridge;
[0020] FIG. 7 is a fragmented, enlarged, cross-sectional view of an
alternative embodiment of a seal member usable in a liquid filter
cartridge;
[0021] FIG. 8 is a side elevational view of a filter cartridge,
constructed according to principles of this disclosure;
[0022] FIG. 9 is a graph illustrating an embodiment of a laser
welding technique for making the liquid filter cartridge of FIGS.
2-6;
[0023] FIG. 10 is a graph showing another embodiment of a laser
welding technique;
[0024] FIG. 11 is a graph showing another embodiment of a laser
welding technique;
[0025] FIG. 12 is a graph showing another embodiment of a laser
welding technique;
[0026] FIG. 13 is a graph showing yet another embodiment of a laser
welding technique; and
[0027] FIG. 14 is a fragmented, enlarged, cross-sectional view of
an alternative embodiment of an inner seal arrangement usable in a
liquid filter cartridge.
DETAILED DESCRIPTION
[0028] A. Typical Systems of Operation
[0029] In FIG. 1, a schematic diagram is illustrated showing a
typical system and application for a filter assembly constructed
according to principles disclosed herein. In FIG. 1, a system is
depicted at 20. The system will include machinery 22 having an
engine 24. The machinery 22 can be an excavator, a skid steer
loader, a lift truck, a tractor, an over the highway truck, a power
boat, a power plant, and other types of machines and equipment.
Machinery 22 will have engines 24 to power machinery 22 in a
variety of sizes and power. Engine 24 will include a lube system or
a fuel system that requires cleaning by a filter assembly 26.
Typical preferred systems 20 will include filter assemblies 26 that
have typical operating pressures of less than about 200 psi (about
1.4 MPa) and impulse fatigue pressures of 0-175 psi (about 1.20
MPa) at 250,000 cycles. Systems 20 will have a variety of engine
sizes including sizes typically at least 10 hp, typically no
greater than about 900 hp (about 670 KW), and in many systems about
50-400 hp (about 30-300 KW).
[0030] Machinery 22 can also have hydraulic systems, in which the
hydraulic fluid will need filtering or cleaning. These types of
systems will use filter assembly 26 to clean the hydraulic fluid.
Filter assemblies 26 that are used for cleaning hydraulic fluid
will have typical operating pressures of less than about 1,000 psi
(about 6.9 MPa). and typical impulse fatigue pressures of 500 psi
(about 3.4 MPa) at 10.sup.6 cycles.
[0031] B. The Embodiment of FIGS. 2 and 3
[0032] Attention is now directed to FIG. 2. In FIG. 2, a filter
assembly 26 is illustrated schematically, in front elevation. The
assembly 26 includes a fluid filter construction or cartridge 40
mounted on a filter head or base 42. Assume, for example, that
assembly 26 is constructed as an oil filter. Oil to be filtered
would generally enter filter base 42 in the direction of arrow 44
through entrance port 46. The fluid flow would be directed through
cartridge 40, for filtering in a preferred manner as described
below. The filtered oil would then pass back into filter head 42
and outwardly therefrom, in the direction indicated generally by
arrow 48 through exit port 50. The entrance port 46 and exit port
50 would be constructed, configured, and positioned appropriately
for connection with suitable couplings and fluid flow conduits.
Periodically, filter cartridge 40 is dismounted from base or head
42 for servicing. Typically, engagement between the filter
cartridge 40 and the head 42 is threaded, with the cartridge 40
being a spin-on filter. Spin-on arrangements are common. In many
instances, cartridge 40 would be designed to be removable and
replaceable. That is, periodically cartridge 40 is replaced with a
new or refurbished cartridge.
[0033] Attention is now directed to FIG. 3. FIG. 3 is a schematic
representation of the filter cartridge 40 of FIG. 2, shown in
cross-section. From a review of FIG. 3, it can be seen that the
particular embodiment shown is a "forward flow" system. That is,
during operation, fluid flow during filtering is from an exterior
region of the filter element to an interior region. Such
arrangements are conventionally known as "forward flow"
arrangements, as opposed to "reverse flow" arrangements, i.e.,
arrangements in which the fluid flow is directed oppositely.
[0034] The preferred filter cartridge 40 includes a housing 52 and
an internally positioned filter element 54. The filter housing 52
includes an outer can 56 and a cover plate or baffle plate 58.
[0035] In preferred constructions, the can 56 has a surrounding
wall 60 that generally approximates a cylinder with a domed or
rounded end wall 62 and defines an open interior 64. The interior
64 functions as a receptacle to receive and contain the filter
element 54. Preferably, the wall 60 of the can 56 is thin, as
compared to the overall radius of the can 56. Preferably, the wall
60 has an average cross-sectional thickness 66 of about one-tenth
or less of the radius of the can 56. In more preferred embodiments,
the average cross-sectional wall thickness 66 is at least about
0.3% and typically about 0.4-1.4% of the inner radius of the can
56. Preferred dimensions for the average cross-sectional wall
thickness 66 is no greater than about 0.048 in. (about 1.2 mm), at
least about 0.008 in. (about 0.2 mm), and typically about
0.015-0.020 in. (about 0.4-0.5 mm). By the term "average
cross-sectional wall thickness", it is meant the thickness of the
wall 60 at any given point. Manufacturing tolerances or other
variations in material and process can cause the wall thickness to
vary somewhat.
[0036] Preferably, the can 56 will be constructed from materials
having high burst strength, yet be inexpensive. Preferred
arrangements include metal. Most preferred arrangements will be
steel. By "steel", it is meant an alloy of iron and between about
0.02 to 1.5% carbon, and may include one or more alloying metals as
additives: chromium, nickel, tungsten, molybdenum, manganese,
vanadium, cobalt, and zirconium. In preferred arrangements, one
example of a usable steel is low carbon steel (i.e., about
0.02-0.3% carbon), having a drawing quality per ASTM A620.
[0037] Still in reference to FIG. 3, the baffle plate 58 preferably
is a stamped metal plate including an outer circular rim 70, a
cover region 72 being circumscribed by the rim 70, and an inner
tubular member 74 being circumscribed by the cover region 72. The
inner tubular member 74 defines an aperture 76 to permit liquid
flow communication with an interior 78 of the filter element 54. In
particular, the tubular member 74 includes a stem or neck 80
defining an outer, annular surface 82. In preferred arrangements,
when the filter assembly 26 operates in a forward flow system, the
tubular member 74 acts as an outlet tube to permit the flow of
cleaned or filtered liquid from the filter interior 78 to the
filter head 42, and ultimately to downstream components.
[0038] The baffle plate 58 is preferably constructed of stamped
metal, preferably steel. In one example, the baffle plate 58 is
constructed of cold rolled, low carbon steel having a thickness no
greater than about 0.164 in. (about 4.2 mm), at least about 0.080
in. (about 2 mm), and typically about 0.102-0.105 in. (about
2.6-2.7 mm).
[0039] The baffle plate 58 may also be constructed of powdered
metal. Powdered metal can be any of several types of metals (iron,
aluminum, chromium, etc.) produced in a powdered form, pressed in a
mold, and heated (sintered) at high temperature.
[0040] The baffle plate 58 also includes a plurality of flow ports
84 to permit liquid flow communication with the interior 64 of the
can 56. In the arrangement depicted in FIG. 3, the flow ports 84
are in the form of apertures 86 defined by the cover region 72.
When the filter assembly 26 is operating in a forward flow system,
the apertures 86 permit the flow of unfiltered liquid from the
filter head 42 through the flow ports 84, and into the interior 64
of the can 56. Typically, the apertures 86 will define an open area
no greater than about 20%, typically about 5-10%, and at least
about 1% of the perimeter area of the baffle plate 58.
[0041] The baffle plate 58 also preferably includes a seat 90 for
holding or containing a seal member 92. In the preferred
constructions, the seat 90 is defined by a groove, or indent, or
channel 94 in the cover region 72. In the particular arrangement
depicted in FIG. 3, the channel 94 is U-shaped. In preferred
constructions, the seal member 92 is wedged into the channel 94 to
form a tight, interference fit between the seal member 92 and the
baffle plate 58. It can be seen in FIG. 3, that the channel 94 is
in the cover region 72 between the outer rim 70 and the region 88
of the baffle plate 58 defining the apertures 86. An alternative
embodiment is shown in FIG. 7. In FIG. 7, the seal member 92' is an
O-ring 93'. The channel 94' permits the O-ring 93' to rotate with
respect to the baffle plate 58' and with respect to the can 56'. A
plurality of projecting tabs 95' aid in retaining the O-ring 93' in
the channel 94'. In another embodiment, the gasket is arranged with
respect to the baffle plate as an "outboard" gasket. This means
that the gasket is arranged close to the outer periphery of the
baffle plate (about 2-8 mm from the periphery of the baffle plate).
Outboard gaskets are typically used for small filter cartridges,
i.e., on the order of 3 inches (about 76 mm) or smaller.
[0042] Referring again to FIG. 3, in the arrangement shown, the
seal member 92 is circular and circumscribes the flow ports 84. The
seal member 92 is axially compressed against filter head 42 to form
a seal between the filter head 42 and the filter cartridge 40. This
seal helps to prevent leakage between the cartridge 40 and the
filter head 42. In preferred constructions, the seal member 92 will
be made from nitrile rubber.
[0043] The outer rim 70 forms and outer periphery 98 of the baffle
plate 58. The outer periphery 98 includes an outer annular surface
100 that, in the preferred construction shown, snugly engages and
abuts an inside surface 102 of the wall 60.
[0044] In the preferred construction shown, the baffle plate 58 is
secured to the can 56 through a connection at the interface of the
annular surface 100 and the inside surface 102 of the can 56.
Preferably, the baffle plate 58 and the can 56 are secured together
by laser welding to form a laser welded bead or seam 110 that fuses
the baffle plate 58 and the can 56 together. By "laser welding", it
is meant a process that applies heat in a concentrated region to
melt the materials (i.e., the can 56 and baffle plate 58) in the
concentrated region and cause fusion, upon cooling of the materials
in the concentrated region. In this case, the heat application is
preferably done with a laser. The laser welded seam 110 provides
for a high strength connection or joint between the baffle plate 58
and the can 56. Indeed, when constructed according to most
preferred arrangements described herein, when the filter cartridge
40 is subject to burst testing, preferred cartridges 40 will fail
along a longitudinal line of the can wall 60, rather than at the
joint between the baffle plate 58 and the can 56. This means that
the filter cartridge 40 is approximating a pressure vessel system,
and is being theoretically optimized for strength. Certain
preferred laser welding techniques are described further below.
[0045] As a result of the seam 110, the outer appearance of the
cartridge 40 is clean, attractive, and seamless, as can be seen in
FIG. 8. Although the techniques described herein can be used to
achieve a variety of appearances, the appearance in FIG. 8 is
preferred due to its attractive, clean, eye-catching
appearance.
[0046] Note that the way in which the can 56 and the baffle plate
58 are secured together eliminates roll or lock seams (i.e., the
can 56 is "roll-seam free" or "lock seam free"). In the prior art,
these roll or lock seams were typically the failure point when the
filter cartridges were subject to burst testing and impulse fatigue
testing. In prior art using roll or lock seams, the failure point
under a burst test would be typically under 200 psi (about 1.4
MPa), more typically at about 180 psi (about 1.2 Mpa), and failure
would occur along the roll or lock seam. When constructed according
to principles described herein, in certain preferred arrangements,
the failure of the cartridge 40 under a burst test will occur at
over 300 psi (about 2.10 MPa), typically over 400 psi (about 2.80
MPa), and in one example, at about 500-800 psi (about 3.4-5.5 MPa),
e.g. about 720 psi (about 5.0 MPa).
[0047] Still in reference to FIG. 3, the filter element 54 includes
filter media 120 bounded by an inner liner 122. The media 120 also
extends between a first end cap 124 and a second end cap 126. A
variety of media configurations and materials can be used for media
120. The particular configuration shown is generally cylindrical
with the media defining interior volume 78. For the arrangement
shown, media 120 comprises a conventional, cylindrical, pleated
filter media potted within end caps 124, 126. In one example, the
specific media 120 usable in these arrangements is resin
impregnated cellulose media In another example, the media 120 can
be pleated synthetic glass fiber filter medium, which is coated and
corrugated to enhance performance in ambient air-oil mist
conditions. The synthetic glass fiber filter media may be coated
with a low surface energy material, such as an aliphatic
fluorocarbon material, available from 3M of St. Paul, Minn. In
another example, the media 120 can be non-pleated depth media.
[0048] The inner liner 122 preferably is constructed of a nonmetal
material, in particular, a hard rigid plastic. In the specific
embodiment shown, the inner liner 122 comprises glass-filled nylon.
Note that the inner liner 122 defines a plurality of apertures or
flow ports 128 between a series of protecting hoops 130. The hoops
130 are supported by a plurality of (typically about 4)
longitudinal members 132. The longitudinal members 132 extend the
length of the inner liner 122 between the first and second end caps
124, 126. Note that the hoops 130 extend or project from the
longitudinal members 132. These projections 134 prevent undue
amounts of filter media 120 from direct contact with solid regions
of the inner liner 122. In certain prior art filter liners that do
not have projections, the filter media that directly interfaces
with the solid portions of the inner liner are dead, unused regions
of filter media because of blockage by the inner liner. In these
prior art arrangements, this masked area of filter media permits
less fluid flow through and increases the restriction and shortens
the life of the filter media. In the embodiment shown in FIG. 3, in
contrast, the projections 134 on each of the hoops 130 decreases
the relative amount of masking, as compared to prior art inner
liners. When constructed according to principles described herein,
the inner liner 122 will mask only at the tips of the projections
134. This will mask no greater than about 35%, typically about
25-30% of the media 120.
[0049] Preferably, the inner liner is constructed to have an open
area of at least about 65%, no greater than about 80%, and
typically about 70-75%. Each of the hoops 130 will be at least 0.5
mm, no greater than about 5 mm., and typically about 1-3 mm. in
thickness. Each of the projections 134 extends a distance beyond an
outermost edge of the longitudinal members 132 of at least about 1
mm., no greater than about 10 mm. and typically about 3-5 mm.
[0050] Preferably, the filter element 54 also includes an outer
liner 138. The outer liner 138 preferably extends between the first
and second end caps 124, 126. The outer liner 138 may comprise a
variety of materials, such as expanded or extruded plastic sleeve
adhesive beads, or fiberglass strand reinforced resin spiral.
[0051] Still in reference to FIG. 3, the preferred first end cap
124 defines an open aperture 142 for permitting liquid flow
communication with the interior volume 78 of the filter element 54.
The open aperture 142 includes an inner, annular surface 144. The
inner, annular surface 144 provides a sealing surface to engage and
abut the outer, annular surface 82 of the neck 80. Preferably, the
open aperture 142 has a smaller diameter than the outside diameter
of the neck 80. Therefore, when the filter element 54 is positioned
over the neck 80, there is an interference fit between the open
aperture 142 and the neck 80. The engagement between the annular
surface 144 of the end cap 124 and the outer annular surface 82 of
the neck 80 forms a radially directed seal 146.
[0052] In order to create the seal 146, the first end cap 124
should be constructed of a compressible, moldable material. In
preferred embodiments, the first end cap 124 is constructed of
urethane or acrylic.
[0053] The first end cap 124 also includes axially extending bumps
or projections 150. Typically, there are at least about three
projections 150 extending from an outer surface 152 (that is, the
surface remote from the media 120). The projections 150 are
constructed and arranged to abut or engage the baffle plate 58. In
the particular construction shown in FIG. 3, the projections 150
engage the channel 94 on a side 154 opposite from the side in which
the seal member 92 engages. The projections 150 help to seat and
appropriately orient the filter element 54 inside of the can 56.
The projections 150 also create a passage to aid fluid flow between
the end cap 124 and the baffle plate 58. The projections 150
typically project at least about 0.080 in. (about 2.0 mm), no
greater than about 0.25 in. (about 6.4 mm), and typically about
0.10-0.15 in. (about 2.5-3.8 mm) above the outer surface 152 of the
first end cap 124.
[0054] The filter element 54 further includes structure for helping
to radially center the filter element 54 within the can 56. In the
embodiment shown, the centering structure includes radially
projecting bumps or projections 156 extending radially from the
filter element 54. The projections 156 can extend from a variety of
regions of the filter element 54, including either one of the first
and second end caps 124, 126. In the particular embodiment shown in
FIG. 3, the projections 156 radially extend from the second end cap
126. Typically, there will be at least two radially extending
projections 156, and usually about 3-6 projections 156. The
projections 156 radially abut and engage the inside surface 102 of
the wall 60. It can be seen in FIG. 3 that the second end cap 126
is sized such that the regions 158 of the end cap 126 that do not
have projections 156 are spaced from the inside surface 102 of the
wall 60 to permit fluid flow therearound.
[0055] The filter element 54 further includes a bypass valve
assembly 160. The bypass valve assembly 160 allows for unfiltered
fluid flow to bypass the media 120, in case of clogged filter media
or cold start surges. This ensures a steady flow of fluid to
downstream equipment and prevents cavitation of pumps or other
downstream equipment.
[0056] The bypass valve assembly 160 can be constructed in a number
of configurations and arrangements. For example, U.S. Pat. Nos.
5,395,518; 3,297,162; 5,037,539; and 4,883,083, the complete
disclosures of each which are incorporated herein by reference,
show a variety of bypass valve arrangements.
[0057] In the arrangement shown in FIG. 3, the bypass valve
assembly 160 includes a valve head 164 compressed against a valve
seat 166 by a biasing member 168, in particular, a spring 170. The
bypass valve assembly 160 includes a rigid structural member 172 to
support the filter element 54 against the end wall 62 of the can
56. The rigid structural member 172 forms a tubular surrounding
wall 174 that includes a plurality of inlet ports 176. The rigid
structural member 172 also defines the valve seat 166 against which
the valve head 164 is compressed.
[0058] In a forward flow system, if the filter media 120 becomes
clogged and the differential pressure across the filter media 120
exceeds the force exerted by the spring 170, the valve head 164
will move away from the valve seat 166 into the interior 78 of the
filter element 54. This will permit fluid to bypass the filter
media 120 and flow through a port 178 defined by the valve seat
166.
[0059] Note that there is no other biasing mechanism or spring
between the filter element 54 and the end wall 62 of the can 56
(i.e., it is a spring-free cartridge 40). Preferably, the only
structure between the filter element 54 and the end wall 62 is the
rigid structural member 172 of the bypass valve assembly 160 (i.e.,
the filter element 54 is supported by a springless member).
[0060] In the embodiment shown in FIG. 3, the bypass valve assembly
160 is press fit by interference fit into an aperture 180 defined
by the second end cap 126. This permits convenient and inexpensive
manufacturing and assembly techniques. In addition, if a bypass
valve is not desired, a solid plug can be easily substituted, to
provide the same function of the rigid, structural member 172.
[0061] C. Example Assembly Methods and Techniques
[0062] The arrangement depicted in FIG. 3 lends itself to
convenient, quick, and inexpensive assembly techniques. In general,
the cartridge 40 is assembled as follows:
[0063] Filter media 120 is fanned around the inner liner 122 and
potted or molded within the first and second end caps 124, 126.
This forms the filter element 154. The bypass valve assembly 160 is
then press fit and secured, by way of interference fit, into the
aperture 180 of the second end cap 126. Next, the neck 80 of the
baffle plate 58 is inserted into the open aperture 142 of the first
end cap 124. This forms radially directed seal 146 between the neck
80 and the first end cap 124.
[0064] Next, the filter element 54 having the valve assembly 160
and the baffle plate 58 secured thereto is inserted into the
interior 64 of the can 56 until the rigid structural member 172 of
the valve assembly 160 engages the end wall 62 of the can 60. This
is also the point where the projections 150 on the first end cap
124 engage the side 154 of the channel 94 of the baffle plate 58.
The inside surface 102 of the wall 60 is engaging the outer annular
surface 100 of the baffle plate 58. This region is then laser
welded, according to certain preferred laser welding techniques
described below, to form the laser welded connection or seam
110.
[0065] The cartridge 40 is then secured to the filter head 42 by
way of conventional techniques, such as spinning-on along threads
81.
[0066] Preferred assembly techniques as those described herein aid
in reducing the effects of tolerance stack up. In other words, many
preferred assembly techniques described herein allow for the
insertion of the filter element 54 into the can 56, until the
filter element 54 bottoms out on the end wall 62 of the can 60. The
baffle plate 58 can then be pushed into the can 60 until the
projections 150 abut and engage the baffle plate 58. It should be
appreciated this lends to flexibility. If tolerances are at
extremes, the baffle plate 58 will typically be able to account for
the differences by being able to be adjusted relative to its
position in the can 56.
[0067] In operation, liquid to be filtered flows through the port
46 (FIG. 2) in the filter head 42, and through the apertures 86 in
the baffle plate 58. The fluid is prevented from flowing directly
to the interior 78 of the filter element 54 due to radially
directed seal 146. The liquid flows through the filter media 120,
into the interior 78, out through the aperture 76 of the baffle
plate 58, into the filter head 42, and out through the port 50
(FIG. 2).
[0068] If the filter media 120 becomes clogged, the liquid will
flow through the ports 176 in the valve assembly 160 and move the
valve head against the spring 170 away from the valve seat 166. The
liquid will then flow directly to the interior 78 of the filter
element 54, and exit through the aperture 76, flow to the filter
head 42 and exit through the port 50.
[0069] Note that the preferred cartridge 40 lacks a spring between
the end wall 62 of the can 60 and the element assembly 54. Also
note that there is no additional gasket required between the
element assembly 54 and the baffle plate 58. This contributes to a
more convenient and less expensive cartridge 40, as compared to
prior art cartridges.
[0070] In addition, the use of the laser welded seam 110 eliminates
use of a roll or lock seam; in preferred constructions, the use of
the laser welded seam improves the burst strength and impulse
fatigue strength. In preferred constructions, there is no gasket
retainer. Thus, the problem in certain existing arrangements of
projection welds between the baffle plate and the gasket retainer
breaking is eliminated.
[0071] D. The Embodiment of FIGS. 4 and 5
[0072] FIGS. 4 and 5 depict an alternative embodiment of a filter
cartridge at 200. Filter cartridge 200 is constructed analogously
as filter cartridge 40 (FIG. 3), with the exception of the inner
liner and the bypass valve assembly, as described below.
[0073] The filter cartridge 200, as with the filter cartridge 40,
includes a can 202, a baffle plate 204, and a laser welded seam 206
securing the baffle plate 204 to the can 202. Inside of the can 202
is a filter element 208, including filter media 210 extending
between first and second end caps 212, 214. There is a radially
directed seal 216 between the first end cap 212 and the baffle
plate 204. A sealing member 218 is held by the baffle plate 204 by
way of interference fit. Each of these features is analogous to
those described, in conjunction with FIG. 3.
[0074] In this embodiment, the inner liner 220 is integral with the
bypass valve assembly 222.
[0075] Attention is directed to FIG. 5. FIG. 5 is a perspective,
exploded view of the filter cartridge 200 of FIG. 4. It can be seen
in FIG. 5 that the rigid structural member 224 of the bypass valve
assembly 222 is molded with and is an integral part of the inner
liner 220.
[0076] To assemble the cartridge 200, the filter media 210 is
potted or molded within the first and second end caps 212, 214. The
valve head 226 and spring 228 is inserted into the rigid structural
member 224 and operably positioned therein. Next, the inner liner
220, including the rigid structural member 224 that is integral
with it, is inserted into the openings defined by the first and
second end caps 212, 214. The inner liner 220 engages the first end
cap 212, while a shoulder 230 on the inner liner 220 is press fit
by way of interference fit into the second end cap 214 to secure
the inner liner 220 and bypass valve assembly 222 to the second end
cap 214. This filter element construction 208 is then assembled
into the cartridge 200, analogously as described above in
connection with FIG. 3.
[0077] E. The Embodiment of FIG. 6
[0078] FIG. 6 illustrates a schematic, cross-sectional view of
another embodiment of a filter cartridge 300. Filter cartridge 300
is constructed analogously as filter cartridge 40, with the
exception of the baffle plate. The filter cartridge 300 includes a
can 302, a filter element 304, and a bypass valve assembly 306. The
filter element 304 includes filter media 308 extending between
first and second end caps 310, 312. An inner liner 314 is potted or
molded within the first and second end caps 310, 312. A rigid
structural member 316 is separate from the inner liner 314 and is
press fit into the second end cap 312.
[0079] The first end cap 310 is generally planar and flat, and does
not have axial projections, such as projections 150 (FIG. 3).
[0080] There is a baffle plate at 320. This is a "wide mouth"
baffle plate and defines an inner rim 321 having threads 322. The
baffle plate 320 is secured to the can 302 by way of a laser welded
seam 324. The baffle plate 320 can have a thickness of typically
0.3-0.5 inches (about 7.6-12.7 mm), and typically not greater than
about 3 inches (about 76 mm).
[0081] This type of filter cartridge 300 is for threading onto a
particular type of filter head assembly different than that
described above for FIGS. 3 and 4. The filter head assembly that
this embodiment would engage separates the unfiltered fluid from
the filtered fluid by way of ports and seals in the filter head
itself. This type of filter head assembly is described in U.S. Pat.
No. 5,342,519, which patent is herein incorporated by reference.
When the cartridge 300 is threaded onto the filter head assembly,
the first end cap 310 will form a radially directed seal between
the outer, annular sealing surface 326 of the first end cap 310 and
an appropriate tubular member in the filter head. Alternatively, an
axially directed seal may be formed, as described below.
[0082] F. Axially Sealing System: the Embodiment of FIG. 14
[0083] FIG. 14 illustrates an enlarged, fragmented, cross-sectional
view of another embodiment of a filter cartridge 400. Filter
cartridge 400 is constructed analogously as filter cartridge 40,
with the exception of the manner in which the filter element 402
seals to the baffle plate 404. Instead of a radially directed seal,
such as seal 146 in FIG. 3, there is a face seal or axially
directed seal at 406. In this embodiment, the seal 406 is formed
between an axial surface 408 of the baffle plate 404 and an axial
surface 410 of an end cap 112.
[0084] As with the embodiment of FIG. 3, there is an outer steel
can 420 that is secured to the baffle plate 404 at a laser weld
422.
[0085] During assembly, the filter element 402 is inserted into an
interior 424 of the can 420. The baffle plate 404 is placed over
the opening to the can 420, and inserted until the axial surface
408 abuts and engages the axial surface 410 of the end cap 412.
After that, the can 420 is secured to the baffle plate 404 by way
of laser welding techniques, as described below.
[0086] G. Laser Welding Techniques, FIGS. 9-13
[0087] As described above, preferably the baffle plate 58 is
secured to the can 56 by way of laser welding to result in laser
welded seam 110. When welding the can 56 to the baffle plate 58, in
particular when the can 56 and baffle plate 58 have different
cross-sectional wall thicknesses, one needs to take into account
the changes in shape due to heat transfer. If the thickness between
the can 56 and baffle plate 58 differ, this can result in gaps
between the baffle plate 58 and can 56 due to thermal growth. The
power output of the laser will depend upon: the total thickness of
the two parts to be welded together; and the required welding speed
(inches per minute). In preferred assemblies, the laser welding
technique will allow for constructing at least 2000 filter
assemblies 26 per hour. In typical, preferred filters, the filter
assemblies 26 will have a diameter of at least about 3 and 5/8ths
inch (92 mm) (although, in many typical embodiments, the diameter
can be smaller) and a circumference of about 11.4 inches (about 289
mm). In order to construct 2000 filters per hour, there needs to be
at least 380 inches/minute (about 9.7 m/min) of welding; typically,
at least 400 inches/minute (about 10.2 m/min) of welding, when
machine set-up time, e.g., loading and unloading is taken into
account.
[0088] In certain constructions, cans 56 having a thickness of
between about 0.015-0.020 inch are to be welded to baffle plate 58
of considerably more thickness, typically at least 200%, more
typically at least 400%, and in some examples over 500% thicker
than the thickness of the can 56. For example, the baffle plate 58
typically has a thicknesses of about 0.102-0.105 inch (about
2.6-2.7 mm). In these examples, the baffle plate 58 is about
510-580% of the thickness of the can 56. Typically, the baffle
plate 58 will be no more that 1000% of the thickness of the can 56.
One method for securing the baffle plate 58 to the can 56 by way of
laser welding is illustrated in FIG. 9.
[0089] In the embodiment of FIG. 9, a plurality of tacks or
stitches between the can 56 and baffle plate 58 are initially
applied. Preferably, the tacks are spaced apart from each other
sufficient to hold the baffle plate 58 to the can 56 and prevent a
gap from forming between the can 56 and baffle plate 58.
[0090] In the embodiment shown in FIG. 9, there are two tacks
formed at points A and C. After the tacks are formed at A and C,
the entire annular surface 100 is laser welded at full power for
360.degree. to result in the laser welded seam 110.
[0091] In FIG. 9, the laser weld is initially started up at a power
P1. This power, if welding at a speed of at least 400 inches/min,
is typically less than 2 kW, typically at least 0.5 kW, and
typically about 1-1.5 kW (e.g., about 1.3 kW). The power is
gradually increased from power P1 to power P2, while the can 56 and
baffle plate 58 assembly are moved rotationally with respect to the
laser weld beam. At rotational position A, the laser power will be
at power P2. Power P2 is a power sufficient to make a stitch or
tack between the can 56 and baffle plate 58. Typically, the power
P2 is at least 3 kW, no greater than 6 kW, and typically about
3.3-3.5 kW (e.g., about 3.4 kW), when welding at a speed of about
400 inches/minute. When the speed is less, the power P2 required to
make the tack can be lower. The rotational position of the can 56
and baffle plate 58 at point A will be about 90.degree..
[0092] The can 56 and baffle plate 58 continue to be rotated with
respect to the laser beam, while the power is ramped down from P2
to P1 between points A and B. Typically, point B will be a
rotational position of about 160-200.degree., i.e., about
180.degree. (from the initial position; that is, about 90.degree.
from position A). Between points B and C, the can 56 and baffle
plate 58 continue to be rotated, while the power is again ramped up
from power P1 to power P2. Point C will correspond to about
270.degree. from the initial position (about 90.degree. from point
B). This will put another stitch or tack weld at point C. After
reaching point C, the power is maintained at power level P2 until
point D. Typically, the can 56 and baffle plate 58 are rotated at
least a full 360.degree. from point C to point D to provide a full,
complete weld or seam 110 between the baffle plate 58 and can 56.
Note that point D also corresponds to at least 630.degree. from the
initial position. After point D, the power is again ramped down,
and the welding assembly is complete.
[0093] Another embodiment is illustrated in FIG. 10. In FIG. 10,
power is once again ramped between levels P1 and P2, but in this
embodiment, there are six tacks or stitches applied between the
baffle plate 58 and can 56 at points A, B, C, D, E, and F. After
these tacks A-F are formed, the baffle plate 58 and can 56 are
rotated at least a full 360.degree. to form a complete,
uninterrupted, continuous laser welded seam 110. This occurs
between points F and G. In certain preferred processes, each of the
tacks A-F will be spaced about 20-40.degree., typically about
30.degree. apart from each other. In some preferred processes, the
power oscillation between the initial position and point F will
approximate a sine wave. In some preferred processes, the power
level P1 will be close to 0, on the order of 100 watts. The power
level P2 will be at least 3 kW, no greater than 6 kW, and typically
3.2-3.5 kW (typically about 3.4 kW), when welding at a speed of at
least 400 inches/minute. If the speed is lower, the power required
may be lowered.
[0094] In another embodiment, there would be about four tacks or
stitches applied between the baffle plate 58 and can 56. After the
four tacks are formed, the baffle plate 58 and can 56 are rotated
at least a full 360.degree. to form a complete, uninterrupted,
continuous laser welded seam 110. In this embodiment, each of the
tacks will be spaced about 35-55.degree., typically about
45.degree. apart from each other. The power oscillation in making
the four tacks can, in certain processes, approximate a sine wave.
The power will oscillate between a power close to 0, on the order
of 100 watts, and up to at least 3 kW, no greater than 600 kW, and
typically about 3.2-3.5 kW, when welding at a speed of at least 400
inches/minute. If the speed is lower, the power required may be
lowered.
[0095] Another embodiment is illustrated in FIG. 11. In this
embodiment, there is a first tack formed between the baffle plate
58 and the can 56 at point B. Power is then ramped down from P2 to
P1, while the combination of the plate 58 and can 56 are rotated
until point C, where the power is held steady at P1, until point D.
Power is again ramped up to power P2 such that another tack is
applied at point E. Power is again ramped down to level P1, while
the combination plate 58 and can 56 is rotated to point F. The
power is again ramped from level P1 to level P2 to apply a tack at
points G. From point G, the power level is dropped until the baffle
plate 58 and can 56 are rotated to point H. At point H, the power
level is maintained at level P1 until reaching point I. From point
I, the power level is ramped up to power P2 at point J. At point J,
the power is maintained at level P2, to apply a continuous,
uninterrupted weld or seam while rotating the baffle plate 58 and
can 56 at least a full 360.degree. until point K, at which point
the weld is completed. In the embodiment of FIG. 11, point B is
spaced about 35-55.degree., typically about 45.degree. from the
initial position point A. Point D is spaced, typically, about
160-200.degree., typically about 180.degree. from the initial
position Point A. Points B and C are spaced about 35-55.degree.,
typically about 45.degree. apart. Similarly, point E is spaced
about 35-55.degree., typically about 45.degree. from points D and
F. Point G is spaced about 35-55.degree., typically about
45.degree. from points F and H. Point I is spaced about
70-110.degree., typically about 90.degree. from point H. Point J is
spaced about 35-55.degree., typically about 45.degree. from point
I. Points J and K are spaced at least about 360.degree. apart from
each other.
[0096] In an alternate embodiment of FIG. 11, the relative power
levels between the tack points (B, E, and G) and the continuous,
uninterrupted weld seam (point J-K) are different. In particular,
the power at the tack points can be less than the power during the
continuous weld seam. In typical arrangements, the power during the
tacking will be about 75-90% of the power during the continuous
weld seam.
[0097] The methods of FIG. 11 can be summarized in the following
table. This table represents certain, typical, convenient values.
Variations from those below are contemplated:
1 TOTAL DEGREES FROM INITIAL POSITION POINT At Least No Greater
than Typical range For example A 0 0 0 0 B 0 120 35-55 45 C 40 200
80-100 90 D 100 260 170-190 180 E 120 270 215-235 225 F 180 350
260-280 270 G 220 360 305-325 315 H 280 500 350-370 360 I 360 580
440-460 450 J 400 600 485-505 495 K 700 900 845-865 855 L 710 1000
890-910 900
[0098] FIG. 12 illustrates another embodiment of a laser welding
technique. In FIG. 12, there are tacks applied at points B, D, and
F, while a full, uninterrupted, continuous seam is applied between
points H and I. In this embodiment, the tacks are applied, while
the laser is at a power that is lower than the power of the
continuous seam. In particular, the baffle plate 58 and can 56
combination is rotated at a slower speed while the tacking is
occurring, versus a higher speed between points H and I when the
continuous, uninterrupted seam is applied. The power is oscillated
between the initial position A and point G between a power level P1
and a power level P2 in a pattern can approximate a sine wave.
Other wave patterns may also be used. In the embodiment of FIG. 12,
each of the tack or spot welds are spaced about 70-110.degree.,
typically about 90.degree. apart. In preferred applications, each
of the spaces between the initial position A, point B, point C,
point D, and on up to point G is about 35-55.degree., typically
about 45.degree. apart. At point G, the power level is increased
from level P1 up to level P3. Level P3 is a higher power than level
P2. Typically, the power level P2 will be 75-95% of the power level
P3. In typical operations, the level P3 will be about 3.2-3.5
kilowatts, while the level P2 will be about 2.9-3.1 kilowatts, when
welding at a speed of at least 400 inches/minute.
[0099] FIG. 13 illustrates another embodiment of a laser welding
technique. In FIG. 13, the tack welds are applied while the baffle
plate 58 and can 56 are rotated at a speed higher than the speed of
rotation while applying the continuous, uninterrupted seam. Tack
welds are applied at points B, D, and F, while a continuous,
uninterrupted seam is applied between point H and L. Each of points
A-H are preferably evenly spaced from each other, about
35-55.degree. typically about 45.degree.. The power is varied
between point P1 and point P2, while applying the tacks at points
B, D, and F. After point G, the baffle plate 58 and can 56
combination can be rotated at a slower speed to permit a joint to
be welded at power level P3. In typical applications, when welding
at a speed of at least 400 inches/minute, the power level P3, in
this embodiment, will be between about 3.2-3.5 kilowatts, while the
power level P2 will be about 105-110% of the power level P3,
typically about 3.6-3.7 kilowatts.
[0100] The methods of FIGS. 12 and 13 can be summarized in the
following table. This table represents certain, typical, convenient
values. Variations from those below are contemplated:
2 TOTAL DEGREES FROM INITIAL POSITION POINT At Least No Greater
than Typical range For Example A 0 0 0 0 B 0 120 35-55 45 C 30 150
80-100 90 D 90 210 125-145 135 E 120 270 170-190 180 F 180 330
215-235 225 G 200 400 260-280 270 H 210 410 305-325 315 I 500 800
665-685 675 J 510 810 710-730 720
[0101] In general, it should be appreciated from the above
discussion that the number of tacks applied between the baffle
plate 58 and can 56 can vary between at least 1 tack, no more than
about 16 tacks, and typically about 2-8 tacks. Preferably, the
processes will have the tacks evenly spaced. In preferred
processes, the tacks are formed by varying the power between a low
power (on the order of 100 watts), up to a power sufficient to form
a tack or spot weld at a fast enough speed (in these examples, at
least 3 kW and a speed of at least 300 inches/minute, typically, at
least 400 inches/minute). The power variance can be in the form of
a saw-tooth wave, a square wave, a sine wave, and other such
patterns. In preferred processes, after the plurality of stitches
or tacks is applied, there will preferably be a complete,
uninterrupted, continuous laser welded seam formed between the
baffle plate 58 and the can 56 by rotating the baffle plate 58 and
can 56 at least a full 360.degree. relative to the laser beam at a
steady power, sufficient to form a joint between the plate 58 and
can 56. In the examples discussed herein, that power will typically
be at least 3 kW, and typically about 3.2-3.5 kW. The rotation
speed can be varied, to permit lower or higher laser power levels.
The rotation speed may also be varied between tacks applied. That
is, there can be one rotation speed during the welding of the tacks
themselves, and a different rotation speed (typically, faster) in
between the welding of the tacks. The speed may also be varied
between the tack application and between the application of the
continuous laser weld seam.
[0102] H. Specific Example Embodiment
[0103] The following section provides example dimensions of one
specific embodiment. It should be understood that a variety of
dimensions and configurations are contemplated.
[0104] The can 56 will have a length of at least a 100 mm, no
greater than 500 mm, typically 150-300 mm, and in one example about
200 mm. The diameter of the can 56 will typically be at least 40
mm, no greater than about 150 mm, typically about 50-100 mm, and in
one example about 90-95 mm.
[0105] The seal member 92 will have a diameter that is 5-25%
smaller than the diameter of the can 56. Typically, the diameter of
the seal member 92 will be on the order of 8-15% smaller than the
diameter of the can 56. The diameter of the seal member 92 will
typically be at least 30 mm, no greater than about 140 mm,
typically about 50-100 mm, and in one example about 80-85 mm.
[0106] The filter element 54 will have a length between the first
and second end caps 124, 126 that is typically at least 70%, no
greater than 95%, and typically about 80-90% of the length of the
can 56. The length will typically be at least about 50 mm, no
greater than about 300 mm, typically about 100-200 mm, and in one
example about 160-180 mm.
[0107] There will typically be at least about 5 inlet apertures 86,
no greater than about 25 apertures 86, typically about 8-15
apertures 86, and in one example 12 apertures 86.
[0108] The outlet 76 will have a diameter that is typically at
least about 5 mm, no greater than about 50 mm, and typically about
10-30 mm.
[0109] The above specification, examples and data provide a
complete description of the manufacture and use of the invention.
Many embodiments of the invention can be made.
* * * * *