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Filter cartridge incorporating a peripheral compatibility matrix

US Patènt # 6863811

Invèntors:	Janik; Leon P. (Suffield, CT)
Assignee:	Stanadyne Corporation (Windsor, CT)
Appl. No.:	284694
Filed:	October 31, 2002

ABSTRACT

A filter assembly employs inward and outward radially displaced portions of a peripheral shoulder on the cartridge as components of a cartridge compatibility matrix. Alternative base assemblies include mounting structures complementary to the configuration of the peripheral shoulder to exclude incompatible cartridges. The peripheral shoulder is preferably a roll seam connecting first and second sections of the filter housing. The invention further contemplates a pattern of radial protrusions from a portion of the cartridge housing received in a base receptacle as part of a cartridge compatibility matrix. The base receptacle is configured to receive only those cartridges having a compatible pattern of radial protrusions. A cartridge compatibility matrix including both inward and outward deformations of a cartridge peripheral shoulder and radial protrusions of the received portion of the cartridge housing can ensure both cartridge compatibility and a particular mounted position of the cartridge relative to the base.

BACKGROUND OF THE INVÈNTION

1. Field of the Invention

This invèntion relates generally to fuel filters employed in connection with internal combustion engines. More particularly, the present invèntion relates to replaceable fuel filter cartridges for removing foreign particles and/or separating water from the fuel supply system of an internal combustion engine.

2. Description of the Related Art

Fuel filter systems to which the invèntion relates commonly employ a disposable filter cartridge that is replaced at pre-established intervals of filter usage. The replaceable cartridge is conventionally secured to a base that defines inlet and outlet connections between the cartridge and the fuel supply system. Numerous retention systems have been employed for securing the filter cartridge to the base and allowing removal of the cartridge for replacement purposes.

In practice, filter cartridge requirements may vary depending upon: the type and make of the internal combustion engine; the specific application for which the engine is employed; the climate in which the engine is operated; and/or regional characteristics as to the quality of the fuel supply. Filter cartridges suitable for replacement in a particular filtration system, commonly vary as to capacity, fluid compatibility and filter media qualities.

One of the recurring problems in assuring filtration system performance is encountered in connection with replacement of the filter cartridge. It is imperative that the replacement cartridge be compatible with the filtering requirements for the fuel system. It is common for filter cartridges to have a generally similar exterior configuration regardless of performance. As a result, a replacement filter cartridge may dimensionally conform to the base of a given fuel filter assembly, and not comply with the applicable specifications for the fuel system and thereby jeopardize the integrity of the fuel filtering system. 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 less costly cartridges which are fully suitable. In practice, replacement cartridges may be so similar in overall configuration that the owner of the vehicle and/or the maintenance technician servicing the internal combustion engine may unknowingly jeopardize the integrity of the filtering system by replacement with a wholly unsuitable cartridge even though the unsuitable cartridge at least cursorily 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.

U.S. Pat. No. 5,035,797, which is assigned to the assignee of the present invèntion, discloses a fuel filter assembly in which a base mounts to the vehicle and a disposable filter cartridge is suspended from the base. The cartridge is retained to the base by a threaded collar that engages against a protruding roll seam structure at the periphery of the cartridge housing. The cartridge is replaced by loosening the threaded collar and dismounting the filter cartridge. A key system is disclosed in which keys axially project from the base through corresponding slots in the end cap of the filter cartridge housing. The dimensions and location of the axially projecting keys ensure compatibility by interfering with mounting and sealing of incompatible cartridges lacking the correct slot configuration. The keys interlock with the slots to mount the cartridge at a fixed angular relationship to the base.

U.S. Pat. No. 5,837,137, which is assigned to the assignee of the present invèntion, discloses a similarly configured fuel filtration assembly (e.g., the cartridge is retained to the base by a threaded collar) incorporating an alternative location and key system. Protrusions from a receiving surface of the base are received in corresponding dimples in the opposing end surface of the cartridge to lock the cartridge at a fixed angular position relative to the base. The protrusions interfere with the mounting and sealing of a non-compatible cartridge having an incompatible pattern of dimples.

A further variation on ensuring compatibility in fuel filtration assemblies similar to those described above is disclosed in U.S. Pat. No. 5,766,463, which is assigned to the assignee of the present invèntion. The disclosed fuel filter cartridge is formed from a pair of shell sections joined along a roll seam to form the retaining shoulder. The generally cylindrical upper portion of the filter cartridge is received within the base. A plurality of arcuate protrusions radially project from the cylindrical upper portion of the cartridge to be received in compatible tracks in the base. The protrusions are disclosed as part of a key code system including the key/slot system described in the '797 patènt. A keying system that relies on protrusions from the received portion of the cartridge housing may permit defeat of the keying system by allowing a cartridge without the protrusions to be received in the keyed base without interference.

An alternative filter cartridge mounting system is disclosed in U.S. Pat. No. 6,187,188, also assigned to the assignee of the present invèntion. The roll seam at the junction of the cartridge housing sections is radially outwardly displaced to form a plurality of retention tabs. The base includes a fixed retaining structure comprising a retaining lip defining a plurality of axial slots in communication with retaining channel portions above the retaining lip. The axial slots are located and dimensioned to be complementary to the retaining tabs of the filter cartridge. The filter cartridge is retained to the base by axially aligning the tabs with the slots and upwardly displacing the cartridge into the receptacle of the base. The cartridge is then rotated so that the tabs are engaged within the retaining channel portions. The '188 patènt discloses that compatibility of the cartridge with the base may be ensured by providing the received portion of the cartridge with arcuate slots to accommodate keys axially projecting from the base as disclosed in the '797 patènt. Alternatively, the received portion of the cartridge may be provided with radial protrusions such as those disclosed in the '463 patènt. Tracks in the base for receiving the protrusions must be L-shaped (have an axial portion and a radial portion) to accommodate rotation of the cartridge relative to the base.

Ensuring filter cartridge compatibility is an issue of continuing concern in the art. While the approaches to ensuring filter cartridge compatibility described in the '797, '137, '463, and '188 patènts represent significant advances over the prior art, further improvements in effectiveness and efficiency are possible. For example, keys projecting from the base that require openings in the filter cartridge compromise the sealed integrity of the filtration system. Keying arrangements that restrict the cartridge to a fixed angular position relative to the base are incompatible with filter assemblies that require rotation of the cartridge relative to the base. The L-shaped tracks disclosed in the '188 patènt may be difficult to produce, thereby increasing the cost of filter assemblies.

There is an ongoing need in the art for a filter assembly that prevents installation of incompatible filter cartridges. Ideally, a filter cartridge compatible with such a key system may be employed with a filter assembly in which the cartridge is retained to the base by a collar and filter assemblies in which the cartridge is rotated to engage radially projecting tabs in a retainer fixedly extending from the base.