Fuel filter assembly with modular drain bowl

A fuel filter assembly incorporates a modular drain bowl which may be removably mounted at the lower end of the disposable filter cartridge. An anchor insert is disposed interiorly at the lower portion of the cartridge sump for anchoring a fastener to attach the drain bowl. The insert also is specially configured to form outlet passages which facilitate the flow of water from the sump to the drain bowl.

BACKGROUND OF THE INVENTION 
This invention relates generally to devices for filtering and separating 
fluids. More particularly, the present invention relates to fuel filters 
for removing foreign particles and separating water from fuel and fuel 
supply systems of an internal combustion engine. 
The absence of high standards and quality control in diesel fuel supplies 
dictates that an effective fuel filter be incorporated into the fuel 
supply system of the diesel engine. It is not uncommon for diesel fuel to 
have significant quantities of abrasive particles and water. The abrasive 
particles present the potential for permanent damage to components of the 
fuel injection pump. In addition, the abrasive particles can adversely 
effect the performance of the pump by destroying the ability of the fuel 
injection pump to precisely meter and deliver fuel at high pressures. The 
presence of water in the diesel fuel supply can cause corrosion of engine 
components, and during freezing conditions, can result in interruption of 
the fuel injection system and/or seizure of moving components. 
Fuel filters commonly employ a disposable filter cartridge which is 
replaced at pre-established intervals of filter usage. There are a wide 
variety of fuel filter cartridge configurations and orientations. The 
replaceable cartridge is conventionally secured to the base and/or locked 
to the base by a locking mechanism which is releasable to allow for 
removal of the cartridge for replacement purposes. 
In U.S. Pat. No. 5,017,285, which is assigned to the assignee of the 
present invention, one disclosed inverted fuel filter assembly employs a 
base which mounts to the vehicle and a disposable filter cartridge which 
is suspended directly below the filter base. The cartridge has a housing 
constructed of a pair of cup-like sections which are joined along a roll 
seam. The roll seam functions as a retaining shoulder for engagement by a 
collar which threads to the base to retain the collar in position. The 
disposable cartridge preferably houses a dual stage filter. The lower 
portion of the housing forms a sump which collects water separated by at 
least one of the filter elements. A central axial opening at the bottom of 
the cartridge housing receives a drain cock. The drain cock threads into 
an insert which is pressed into the interior lower end of the cartridge 
housing. Water may be drained from the cartridge by opening the drain 
cock. 
For certain applications, it is highly desirable that a drain bowl for the 
separated water be provided in conjunction with the fuel filter. The drain 
bowl functions to provide additional capacity for retaining the separated 
water. In addition, the drain bowl may be constructed of transparent 
materials which allow for ready exterior inspection of the water level so 
that the water may be drained from the bowl before maximum capacity is 
reached, and the effectiveness of the water separating properties of the 
fuel filter may be monitored. 
The conventional employment of a drain bowl in conjunction with a fuel 
filter cartridge has essentially involved integrating the somewhat bulky 
drain bowl structure with the filter assembly or the filter cartridge. 
Naturally, the implementation of an effective fluid seal and the provision 
of mounting structure having a structural integrity sufficient to support 
the bowl are requisite to incorporating a drain bowl into the fuel 
assembly. In some applications, the filter cartridge is significantly 
modified so that it will directly accept or mount the drain bowl in a 
permanent fashion. 
A problem associated with the use of drain bowls and the use of drain 
mechanisms for removing the separated water in general is providing a 
drain passage structure which will produce a sufficient rate of fluid or 
water flow. Because the filtering and separating functions of the fuel 
filter are conducted in a closed structure, in practice the draining of 
separated water from the cartridge housing tends to occur at a very low 
rate. The low drain rate can be attributed in part to the relatively small 
conventional drain openings, the surface tension of the separated water in 
the vicinity of the drain openings, and the unfavorable pressure 
differentials exerted on the separated water. In a number of applications 
which employ a drain bowl, the passage of separated water to the drain 
bowl is very inefficient and/or the draining of the separated water from 
the bowl or the cartridge is problematical. 
SUMMARY OF THE INVENTION 
Briefly stated, the invention in a preferred form is a modular fuel filter 
assembly comprising a base and a disposable cartridge which is mounted to 
the base and releasably secured thereto by means of a retainer element. 
The cartridge includes a housing which houses a dual stage or other type 
filtering system. When the cartridge is disposed in an inverted 
orientation relative to the base, the lower portion of the housing 
functions as a sump for collecting separated water. The lower portion of 
the cartridge also includes an opening for the sump. An insert is disposed 
at the housing interior adjacent the opening. The insert is adapted for 
threadably receiving either a drain cock or a fastener for mounting a 
modular drain bowl. The modular bowl is mountable at the lower end of the 
cartridge. The insert is structured so that the separated water 
efficiently passes from the sump at the lower portion of the cartridge to 
the bowl. 
The drain bowl is modular in that the bowl may be dismounted from the 
cartridge and replaced with a drain cock to provide a conventional fuel 
filter cartridge configuration. For applications which require a drain 
bowl, the drain cock may be easily removed from the cartridge, and the 
bowl readily mounted to the lower end of the cartridge. In some 
embodiments, the removed drain cock may then be threaded into a drain 
passage of the drain bowl. 
Preferably, the drain bowl is formed of a transparent material which allows 
for the level of separated water in the bowl to be readily inspected from 
a position exteriorly of the drain bowl. Fluid communication between the 
sump of the cartridge and the drain bowl is facilitated by drain apertures 
formed in the specially configured insert. The insert comprises a lower 
plug portion which is pressed into the central axial protruding end of the 
cartridge housing and an elevated platform disposed above the plug 
portion. The platform has the central threaded opening for anchoring the 
drain cock or the modular bowl fastener. The platform is supported by 
angularly spaced legs which further define the apertures. The legs and the 
apertures are angularly disposed about the central axis of the threaded 
opening. In one embodiment, there are three such apertures which 
essentially function to provide an aspirated passage from the cartridge. 
An object of the invention is to provide a new and improved fuel filter 
assembly which employs a modular drain bowl. 
A further object of the invention is to provide a new and improved fuel 
filter assembly wherein a drain bowl may be easily and efficiently mounted 
and/or dismounted as desired from an end of a disposable filter cartridge. 
A further object of the invention is to provide a new and improved fuel 
filter assembly which incorporates a modular drain bowl and includes a 
passage structure to allow an efficient flow rate of separated water from 
the lower sump of the cartridge. 
Other objects and advantages of the invention will become apparent from the 
drawings and the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to the drawings wherein like numerals represent like parts 
throughout the several FIGURES, a fuel filter assembly incorporating a 
modular drain bowl in accordance with the present invention is generally 
designated by the numeral 10. Fuel filter assembly 10 comprises a base 12, 
a disposable cartridge 14 and a modular drain bowl designated generally by 
the numeral 16. The fuel filter assembly 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 the fuel and for separating water from the fuel. The separated 
water flows to the drain bowl for retention. The separated water is then 
selectively drained from the drain bowl as required. 
In the preferred environment, the base 12 is disposed generally above the 
filter cartridge 14 which is locked to the base by means of a retainer 
collar 18, and the drain bowl 16 is disposed below the filter cartridge. 
The drain bowl 16 has a modular construction which permits the drain bowl 
to be mounted and/or dismounted from the filter cartridge at the option of 
the vehicle operator, as will be detailed below. The filter cartridge 14 
is specifically adapted to be fully functional with or without the 
associated drain bowl 16. 
The base 12 and the disposable cartridge 14 may assume a wide variety of 
configurations. For the disclosed embodiment, the base 12 includes an 
inverted cup-like receptacle 20 which forms a skirt defining a lower 
receiving cavity for upper portions of the disposable cartridge. A central 
stepped axial bore 22 on the base closely receives an elongated 
sleeve-like conduit 24 and an outer concentric sleeve-like conduit 26. The 
conduits provide generally coaxial fluid communication between the base 
and the disposable cartridge. An inlet connector (not illustrated) located 
at an upper side location of the base connects with the fuel line to 
provide fluid communication through the passageway defined by the first 
conduit 24. An outlet connector (not illustrated) also located at an upper 
side location of the base connects with the fuel line to provide remote 
fluid communication from the axial fluid passageway defined between the 
first and second conduits 24 and 26. An integral projecting bracket 40, 
which may include a pair of openings for anchoring the filter base to the 
engine header, projects transversely at the rear of the base. 
The disposable filter cartridge 14 comprises a can-like container 
constructed from a pair of upper and lower cup-like sections 42 and 44 
which are joined along circumferential roll seam 50. The upper section 42 
is dimensioned to be relatively closely received by the base receptacle 
20. The upper section 42 includes a central axial opening. A sealing 
grommet 46 mounted at the axial opening diametrally seals against the 
outer conduit 26. An integral annular lip 47 projects from the top surface 
of the upper section 42. 
In a conventional fashion, a secondary filter element 52, which has a 
continuous fan-shaped pleated configuration, is mounted in the upper 
section. The lower end of the secondary element is engaged by a multi-bent 
medial plate 54 which has a central recess. A second sealing grommet 56 
mounted at the recess diametrally seals the first conduit 24. A primary 
filter element 58, which also has a continuous fan-like configuration, 
engages the underside of the medial plate and is retained by a lower plate 
60. The primary filter element 58 is housed in the lower section 44. A 
sump 62 is formed at the bottom of the lower section to collect water 
which coalesces from the fuel. A central axial protrusion 64 of the 
housing includes an opening 65 which leads from the sump 62. 
The disposable cartridge 14 is retained to the base 12 by means of the 
retainer collar 18. The collar includes an inwardly projecting annular 
shoulder 66 which engages the roll seam 50 of the cartridge for 
retentively locking the disposable cartridge to the base. The collar may 
threadably engage with the base or may include a pair of spiral followers 
68 which interact with ramps formed at the exterior of the base. For the 
disclosed embodiment, a positive locked position of the retainer collar is 
releasably retained by the spring force of a spring washer 69 with an 
inscribed star-like configuration. Leaves of the spring washer angularly 
alternate and are alternately biased so that the one set engages the base 
and the other set engages at the top of the disposable cartridge. A 
peripheral shoulder portion of the spring is also engagable against the 
upper protruding lip 47 of the disposable cartridge. The spring bias 
provides a positive releasable locking engagement of catches of the 
followers to releasably lock the disposable cartridge to the base. 
The disposable cartridge may also include a volume plug 70 which is 
retained by an endcap 72 and includes a column 74 which extends axially in 
the first conduit. The plug 70 functions to occupy a pre-established 
volume of the cartridge when the cartridge is mounted to the base so that 
upon dismounting of the cartridge for replacement, excess fuel which 
drains under the force of gravitation from the base will be retained in 
the cartridge and occupy the free volume gained by dismounting the 
cartridge. 
The modular drain bowl 16 is formed by a pair of cooperative members 80 and 
82 which mate to form a watertight enclosure. The upper cover member 80 
has an upper surface with a concave contour which closely mirrors the 
exterior surface of the lower end of the cartridge. The upper member 
includes a central axial recess 84 which receives the axial protrusion 64 
of the sump opening of the cartridge. A radially peripheral portion of the 
upper member forms a cylindrical skirt having a flange 86 which inwardly 
closely receives an upper end of the lower member. The lower bowl member 
forms a quasi-annular bowl which is centrally defined by a central slotted 
axial column 90 formed by cooperative integral structures of the members 
80 and 82. A radially compressible seal ring 92 is disposed between 
opposed shoulders 94 and 96 of the respectively lower and upper members 
adjacent the skirt flange 86 for fluidly sealing the upper member with the 
lower member. A second seal ring 98 seals the upper member in fluid tight 
relationship against the outer surface of the cartridge along a sealing 
interface which surrounds the axial protrusion 64 of the cartridge 
housing. A third seal ring 101 is provided for fluidly sealing at the 
tapered outer recessed shoulder 103 of central bore 105 passing through 
member 82. Preferably, the lower member 82 and optionally upper member 80 
are formed of transparent materials, such as plastic, which allow for any 
water which is collected in the formed bowl to be readily visible for 
inspection from an exterior position. 
A lower off-center portion of the bowl member 82 has a threaded opening 97. 
A drain cock 99 is threaded to the opening to provide a valved drain 
passage so that collected water may be drained from the bowl as required. 
The drain cock 99 may have a conventional form and function such as a 
drain cock which is conventionally mounted to a filter cartridge for 
draining the cartridge sump 62. 
With additional reference to FIGS. 2 and 3, the modular bowl 16 is fastened 
to the cartridge through an insert 100 which is disposed interiorly at the 
lower end of the cartridge housing adjacent the sump opening. The insert 
100 includes a contoured lower plug 102 having a lower reduced diameter 
and an upper enlarged diameter. The lower plug portion is exteriorly 
contoured for press fitting in the protrusion 64 at the lower interior of 
the cartridge housing. The plug has an opening 104 which communicates with 
the sump opening 65. Three equiangularly spaced legs 106 integrally extend 
from the plug at an oblique angle and integrally connect with a platform 
110. The platform has a central axial opening which is defined by a 
threaded surface 112. Three angularly spaced apertures 114 are thus 
defined by the legs to provide communication through the plug opening 104 
and the cartridge opening 65. 
A head-head bolt 120 is inserted through the axial cavity of the bowl 
members formed by the slotted column 90. The head of the bolt engages the 
recessed shoulder 103 in the lower member. The shank of the bolt threads 
into the threaded surface 112 of the platform for fastening the modular 
bowl to the cartridge. The bolt is tightened to axially load the seal 
rings 98 and 101 so that in conjuction with seal 92, the upper and lower 
members cooperate to seal the bowl in fluid tight relationship with the 
cartridge. 
The apertures 114 defined by the insert function as an aspirated opening to 
facilitate the efficient passage of water collected in the cartridge sump. 
In addition, the insert 100 can be employed for threadably receiving the 
drain cock 99 when the modular drain bowl is not desired. An insert or 
molded member (not illustrated) similar to insert 100 may also be located 
at the drain bowl opening for mounting the drain cock. 
The filter assembly is modular in that the drain bowl may optionally be 
dismounted by unthreading the bolt from the insert 100 and remounting the 
drain cock 99 at the cartridge opening by threadably engaging the drain 
cock into the insert. The insert in the latter configuration functions to 
provide an aspirated opening for fluid passage through the drain cock. 
While a preferred embodiment of the foregoing invention has been set forth 
for purposes of illustration, the foregoing description should not be 
deemed a limitation of the invention herein. Accordingly, various 
modifications, adaptations and alternatives may occur to one skilled in 
the art without departing from the spirit and the scope of the present 
invention.