Background of the Invention
This invention relates generally to fuel filters employed in connection
with internal combustion engines. More particularly, the present invention relates
to fuel filters and lubricating oil filters having a replaceable cartridge for
removing foreign particles and/or separating water from the fuel supply or oil
system of an internal combustion engine.
Conventionally, fuel filters employ a disposable filter cartridge
which is replaced at pre-established intervals of filter usage. In practice, the
filter cartridge requirements may vary depending upon such characteristics as the
type and make of the internal combustion engine, the specific application for which
the engine is employed, the climate in which the combustion engine is operated,
and/or regional characteristics as to the quality of the fuel supply. The filter
cartridges which are suitable for replacement, thus commonly vary as to axial dimensions,
capacity and filter media qualities.
One of the recurring problems in assuring quality fuel filter performance
is encountered in connection with the replacement of the fuel cartridge. It is
imperative that the replacement cartridge be compatible with the filtering requirements
for the fuel system. Because for numerous types of qualities, the filter cartridge
may dimensionally conform to the base of a given fuel filter assembly, replacement
filter cartridges of inferior quality may not comply with the applicable specifications
for a given fuel filter assembly and thereby jeopardize the integrity of the fuel
filtering system. The replacement with an incompatible filter cartridge can have
very serious consequences for the operation of the internal combustion engine and
may also be unnecessarily more expensive than the less costly cartridges which
are fully suitable. In practice, the owner of the vehicle and/or the maintenance
technician servicing the internal combustion engine are frequently totally unaware
of replacement cartridge specifications and requirements and unknowingly jeopardize
the integrity of the filtering system by replacement with a wholly unsuitable cartridge
even though the unsuitable cartridge at least cursorily visibly appears to be suitable.
There are also, of course, instances where inferior or improper replacement filter
cartridges are intentionally installed without the knowledge of the owner of the
operator of the vehicle.
For many applications, it is also desirable that a cartridge be mounted
to the base at a specific angular orientation so that warnings, directions and
markings affixed to the cartridge may be properly positioned to ensure visibility
and maximize the chances of successful information dissemination. For other applications,
it is desirable that the cartridge be locked in position relative to the base such
that the cartridge may not rotate with relation to the base.
Summary of the Invention
Briefly stated, the invention in a preferred form is a location and
key system for locating and keying a replaceable filter cartridge to the filter
The filter system is of a type having a base with an inlet and an
outlet connection with the engine fuel system and a replaceable filter cartridge
mountable to the base. The replaceable cartridge includes a generally cylindrical
housing which houses the fuel filter elements. At least one key or protrusion protrudes
longitudinally from the bottom surface of the base. A corresponding dimple in the
cartridge is dimensioned and located on the top surface of the cartridge for axially
receiving each corresponding protrusion for locking the cartridge at a fixed angular
position of the base.
A unique matrix of longitudinally protruding protrusions is formed
on each base of a given type, and a unique matrix of dimples corresponding to
the protrusions is formed in each cartridge. The protrusion/dimple matrices are
configured so that for a given compatible cartridge and base, the protrusions are
interlockable in the dimples to lock the cartridge at a fixed angular position
of the base to thereby permit the cartridge to be securely mounted to the base.
For non-compatible cartridges and bases, the base protrusions are not mateable
and essentially interfere with the mounting and sealing of the non-compatible
cartridge so that compatible and non-compatible cartridges may be readily identified.
It is known in a filter system to provide cooperating protrusions
and recesses for controlling the replacement of the filter cartridge. However,
the recesses are holes in the housing of the cartridges thus creating possible
problems of fuel leaking out through these holes (EP 0 442 365 A2). It is also
known to provide protrusions 100 a, 100 b, ... at the outer wall of the cartridge
extending radially (EP 0 532 161 A1). It will be necessary to angularly align the
cartridge with the base when inserting the cartridge of the base already at a relatively
early stage of the insertion process. It will be easier to insert the cartridge
of the inventive system because the self-locating action takes place only after
the cartridge has been nearly completely inserted into the base. At the same time,
because the dimples are closed, the disadvantage of recesses in form of holes is
An object of the invention is to provide a new and improved location
and key system for a fuel filter system.
Another object of the invention is to provide a new and improved
replacement cartridge location and key system for efficiently controlling the replacement
of the filter cartridge with a compatible replacement cartridge.
A further object of the invention is to provide a new and improved
location and key system wherein the cartridge is mounted to the base in a pre-established
fixed angular orientation.
A yet further object of the invention is to provide a new and improved
location and key system for locking the cartridge to the base and thereby preventing
Other objects and advantages of the invention will become apparent
from the drawings and specification.
Brief Description of the Drawing
The present invention may be better understood and its numerous objects
and advantages will become apparent to those skilled in the art by reference to
the accompanying drawing in which:
Detailed Description of the Preferred Embodiment
- Figure 1 is a sectional elevational view of a fuel filter assembly in accordance
with the invention;
- Figure 2 is an enlarged fragmentary sectional view, partly in schematic, of
the fuel filter assembly of Figure 1;
- Figure 3 is an enlarged fragmentary sectional view of the filter base and filter
cartridge of Figure 1 showing the filter cartridge partly disassembled from the
- Figure 4 is an enlarged sectional view of Area A of the fuel filter assembly
of Figure 2;
- Figure 5 is an enlarged bottom plan view of the base portion of the fuel filter
assembly of Figure 1;
- Figure 6 is an enlarged perspective view of the base portion of the fuel filter
assembly of Figure 1; and
- Figures 7a, 7b and 7c are enlarged bottom plan views of the base portion of
the fuel filter assembly of Figure 1 showing alternate embodiments of the protrusions.
With reference to the drawings wherein like numerals represent like
parts throughout the several figures, a fuel filter assembly in accordance with
the present invention is generally designated by the numeral 10. Fuel filter assembly
10 comprises a base 12 and a disposable filter cartridge 14. The base 12 is disposed
generally above the disposable filter cartridge 14 which is locked to the base
12 by means of a retainer collar 16. Alternatively, the base and filter cartridge
may be inverted wherein the filter cartridge is disposed above the base. The fuel
filter assembly 10 is especially adapted for incorporation into the fuel supply
system of an internal combustion engine (not illustrated), such as a diesel engine,
for removing particulate matter from fuel and separating the water from the fuel.
Filters of this type may also be used to filter impurities from oil in the lubricating
system of an internal combustion engine.
The base 12 and the disposable cartridge 14 may assume a wide variety
of configurations. For the disclosed embodiment, the base 12 is an inverted cup-like
receptacle which forms a skirt 18 defining a lower receptacle cavity 20 for upper
portions 22 of the disposable cartridge 14. An elongated sleeve-like first conduit
24 and an outer concentric sleeve-like second conduit 26 provide generally co-axial
fluid communication between the base 12 and the disposable cartridge 14.
With reference to Figure 6, an inlet connector 28 at an upper side
location of the base 12 connects with the fuel line (not illustrated) to ultimately
provide fluid communication through the interior passageway defined by the first
conduit 24. An outlet connector 30 at an upper side location of the base 12 connects
with the fuel line to provide external fluid communication from the axial fluid
conduit defined between the first and second conduits 24, 26. An integral projecting
bracket 32 which may include a pair of openings 34 for anchoring the filter base
12 to the engine header extends transversely from the base 12. The base 12 may
also have an external air vent 36.
The base 12 may include a pair of integral outwardly projecting diametrically
opposed ramps 38 which ascend in spiral-like fashion around the base 12. The upper
ends of the ramps 38 are beveled. The collar 16 includes a pair of diametrically
disposed spiral followers (not shown) which integrally extend inwardly from the
collar 16. The followers are dimensioned and positioned for engagement with the
ramps 38 so that the followers slidably engage and ascend the ramps 38 upon alignment
and angular rotation of the collar 16. The collar 16 includes an inwardly projecting
annular shoulder 40 which engages the roll seam 42 of the cartridge 14 for releasably
locking the cartridge 14 to the base 12.
With reference to Figures 1 and 2, a locking force is releasably
maintained by the force of a spring 44 which is retained in an annular recess 46
in the base 12. The recess 46 is positioned adjacent the skirt 18 of the base 12.
Some conventional filter assemblies include a spring for providing a locking force.
Typically, such springs are positioned closer to the axis of the filter base/cartridge
than the spring 44 of the subject invention. Springs 44 located closer to the periphery
of the filter base/cartridge may provide greater stability than do springs located
closer to the axis. In addition such location allows room for key/locating protrusions
48, 86, 88, 90 (Figures 5, 7a-7c) that protrude downwardly from the lower receiving
surface 50 of the base 12. A preferred embodiment is a wave spring having an upper
surface 52 that abuts the surface of the recess 46 and a lower surface 54 that
engages an annular ridge 56 on top portion 58 of the upper section 62 of the filter
cartridge enclosure 60. The spring 44 functions to substantially uniformly distribute
the load between the base 12 and the filter cartridge 14.
A key system is employed to angularly fix the direction of the cartridge
14 relative to the base 12, to provide a system wherein only a proper replacement
cartridge 14 may replace the cartridge once the installed cartridge is spent, and
to lock the cartridge 14 to the base 12 and thereby prevent rotation therebetween.
In a preferred form, a plurality of longitudinally extending keys or protrusions
48, 86, 88, 90 (Figures 5, 7a-7c) protrude from the bottom surface 50 of the base
12 intermediate the recess 46 and the second conduit 26. Preferably, the protrusions
48, 86, 88, 90 are disposed substantially equidistantly between the second conduit
26 and the recess 46. The protrusions 48, 86, 88, 90 are selectively dimensioned
and positioned to provide a unique protrusion matrix for a given filter capacity,
filtering quality or filtering parameter. The protrusions may have the shape of
a spherical sector cap 48, a pie wedge-shape 86, a square-shape 88, a bead or
bump 90, or other non-spherical shape, as shown in Figures 4, 5 and 7a-7c. Preferably,
the protrusions 48, 86, 88, 90 project at least 0.150 inches from the lower surface
50 of the base 12. For filter assemblies 10 which require a positioning and/or
locking system but that do not require a key system, the protrusions 48, 86, 88,
90 may be spaced substantially 120° apart, as shown in Figure 5 at 49.
With reference to Figures 1 and 2, the disposable filter cartridge
14 comprises a can-like enclosure 60 formed by a pair of opposed lower and upper
cup-like sections 64, 62. The sections 62, 64 are joined along a circumferential
roll seam 42. A sump 66 is formed at the bottom of the lower section 64 to collect
water which coalesces from the fuel. The upper section 62, which is smaller in
diameter than the lower section 64, is received by the base receptacle 20. The
upper section 62 is dimensioned to be closely accommodated in the base receptacle
20. A central axial opening 68 in the upper section 62 is dimensioned to receive
the conduits 24, 26. A sealing grommet 70 mounted at the opening 68 diametrally
fluidically seals against the outer conduit 26.
The cartridge 14 may employ a dual stage filter assembly or a single
stage assembly as illustrated in Figures 1 and 2. A filter element 72 which has
a continuous fan-shaped pleated configuration is mounted in the enclosure 60. The
lower end of the element 72 is engaged by a medial plate 74 having a central opening
76. A tubular conduit 78 extends upward from the medial plate 74. The tubular conduit
78 upper end defines a flange 80. A second sealing grommet 82 mounted to the flange
80 receives and diametrally seals against the lower end of the base first conduit
The top portion 58 of the upper section 62 of the filter cartridge
enclosure 60 has a longitudinally upward bend configuration which forms the annular
ridge 56. Preferably, the ridge 56 is disposed along the circumference of the top
portion 58. The top portion 58 further comprises a plurality of integrally formed
dimples 84 disposed intermediate the annular ridge 56 and the central opening 68.
The dimples 84 are relatively shallow depressions. The dimples 84 are complementary
with the protrusions 48, 86, 88, 90 and are dimensioned and positioned for receiving
the protrusions 48, 86, 88, 90. In a preferred embodiment, the protrusions 48,
86, 88, 90 are machined to ensure that the protrusions 48, 86, 88, 90 may be firmly
seated in the dimples 84. In a preferred embodiment for the spherical sector cap
protrusion 48, the radius R1 of each dimple 84 is greater than the radius R2 of
each protrusion 48, (as shown in Figure 4) to ensure that each protrusion 48 may
be firmly seated in the corresponding dimple 84.
It should be appreciated that the invention could also be implemented,
perhaps less easily, if the top portion comprised a unique protrusion matrix and
the base comprised complementary dimples. It should also be appreciated that the
location and key system of the subject invention prevents rotation of the filter
cartridge 14 relative to the filter base 12 due to vibration.
The fuel enters the fuel filter assembly 10 through the fuel inlet
passage 28 and exits the filter through the outlet passage 30. It will be appreciated
that the fuel flow path initially axially traverses through the interior of the
inner conduit 24. The circulation path extends generally axially upwardly and generally
radially through the filter element 72 with the return flow path traversing between
the inner conduit 24 and the outer conduit 26.
The lower surface of the base may include one or more recesses which
receive a protrusion formed in the top portion of the filter cartridge by the operating
pressure of the fuel.