Liquid purification or separation – Diverse distinct separators – Including a filter
Reexamination Certificate
1999-10-15
2001-01-16
Savage, Matthew O. (Department: 1723)
Liquid purification or separation
Diverse distinct separators
Including a filter
C210S316000, C210S342000, C210S438000, C210S450000, C210S487000, C210S497010
Reexamination Certificate
active
06174438
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to filter assemblies and filter elements therefor. Specifically, this invention relates to fuel filter assemblies and fuel filter elements for vehicles that provide enhanced filtration of fuel prior to delivery to the engine of the vehicle.
BACKGROUND OF THE INVENTION
A vehicle fuel system typically has a fuel tank for holding a supply of liquid fuel for delivery to an engine. The fuel system also includes a lift or transfer pump for pumping fuel from the tank to the engine. Some engines, particularly those that have fuel injection, also have an injection pump that raises fuel pressure beyond that produced by the lift pump so that the fuel may be injected at high pressure into the combustion chambers of the engine.
Fuel filters are known for such fuel systems to remove contaminants such as dirt and water from the fuel before it reaches the engine. Fuel filters have been used in the fuel system either at the vacuum side or the pressure side of the fuel pump. Each position for the fuel filter in relation to the lift pump has advantages and disadvantages.
One filter assembly developed by the assignee of the present invention to overcome some of these disadvantages is shown in Hodgkins, U.S. patent application Ser. No. 08/512,352 filed Aug. 8, 1995 for “Double Pass Fuel Filter Assembly”, now U.S. Pat. No. 5,922,199. This assembly includes a filter cartridge with first and second filter media loops, the second media loop surrounding the first media loop, and the first filter media loop providing primary filtration for fluid flowing from a first inlet port to a first outlet port. The second filter media loop, which is fluidly separated from the first filter media loop by a cup-shaped chamber, provides secondary filtration for fluid flowing from the second inlet port to a second outlet port.
According to the Hodgkins reference, the first inlet port of the assembly is connected to receive fuel from a tank, while the first outlet port is connected to supply filtered fuel to the inlet port of a lift pump. The outlet port of the lift pump is connected to the second inlet port in the assembly to receive the filtered fuel, while the second outlet port is connected to provide highly filtered fuel to the engine. The first media loop provides primary filtration for the fuel prior to being supplied to the lift pump, while the second media loop provides secondary (enhanced) filtration prior to being supplied to the fuel injection pump in the engine. Both filter media loops are replaced when the filter element is changed.
The Hodgkins filter assembly has the advantage of providing filtration prior to fuel passing to the lift pump. This minimizes the risk that large and potentially damaging impurities will reach the lift pump. The assembly also serves to remove large impurities before they are broken up or emulsified by the pumping action of the lift pump. These large impurities are captured in the first filter media loop and are periodically drained or dumped out of the assembly when the filter element is replaced. A further advantage is that by having fuel undergo primary filtration before reaching the lift pump, the life of the fine filter media in the secondary filter media loop is prolonged. A still further advantage is that the dual filtration is provided in a single filter assembly that is relatively small and easy to mount to the fuel lines.
While the Hodgkins filter assembly has many advantages over prior filter assemblies, the Hodgkins assembly is not appropriate for all applications, as it is generally designed for a specific head structure. That is, the filter head for the Hodgkins assembly includes all four ports to receive fuel for the two fuel paths through the element. The filter element is located in a canister that is attached with a locking ring to the underside of the filter head. To replace the filter element, the fuel in the canister must be initially drained through a drain port, the locking collar for the canister removed, the canister moved downwardly away from the head, and then the filter element removed from the canister. This can be awkward and time-consuming. In addition, any fuel remaining in the head can drip onto the hands of the user or onto the engine block when the canister is removed.
As such, it is believed there is a demand in the industry for a further improved filter assembly and element that provides dual fuel paths for enhanced filtration of fuel, and which provides easy access to and replacement of the filter element for the assembly, without time-consuming steps or spillage.
SUMMARY OF THE PRESENT INVENTION
The present invention provides a novel and unique filter assembly, and filter element therefor, where the filter assembly provides dual filtration of fuel prior to delivery to an engine, and provides for easy access to and replacement of the filter element.
According to the present invention, the filter assembly includes a cylindrical canister with a threaded open end, and a cover that can be screwed onto and off of the end of the canister. A filter element is located in the canister through the open end of the canister and the cover is removably attached to the opening of the canister to enclose the element. The inlet and outlet ports to the assembly are located in the sidewall and/or lower end of the canister which allows the element to be easily replaced without spillage.
A fitting in the lower end of the canister supports a central conduit extending axially through a portion of the canister toward the open end. The central conduit is bisected along its length into two flow channels. The inner end of one of the channels is plugged, and an opening is provided into the channel through the side of the conduit. The inner end of the other channel is open. An annular channel is also provided in the fitting surrounding the central conduit.
A first inlet port and first outlet port are provided in the canister to direct fuel from the tank to the lift pump in a primary flow path through the canister. The inlet port is formed in the fitting at the lower end of the canister and directs fuel axially upward through the first channel in the conduit to the opening in the side of the conduit, where the fuel then flows radially outward, and then axially downward around and radially inward through a first (primary) media loop of the element. The fuel then flows down through the annular channel surrounding the central conduit, and then out through the first outlet port in the fitting. The first outlet port is disposed in the sidewall of the canister. The fuel is then provided to the inlet port of the lift pump.
The outlet port from the lift pump is connected to a second inlet port, formed in the sidewall of the canister. The fuel then flows radially inward through a second (secondary) media loop of the element. The filtered fuel then flows axially downward through the open end of the second channel in the central conduit to a second outlet port in the fitting, formed in the lower end of the canister. The fuel is then provided to the combustion chamber of the engine.
The filter element for the assembly includes first and second imperforate end caps, with the second end cap having a central circular opening dimensioned to receive the conduit and fitting of the housing. An annular seal or gasket bounds the opening to seal against the fitting. The second filter media loop is provided in surrounding relation to the first media loop, and extends between and is adhesively bonded to the first and second end caps.
The first media loop is attached at a first end to the second end cap (bounding the central opening) and extends axially inward toward the first end cap. The inner end of the first media loop defines an opening which receives the central conduit, and includes an annular seal or gasket to seal against a first location the conduit.
An imperforate cylindrical wall is disposed radially between the first and second media loops. The cylindrical wall includes a first end integral with the second end cap (also
Hodgkins David H.
Stone Walter H.
Hunter Christopher H.
Parker-Hannifin Corporation
Savage Matthew O.
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