BACKGROUND OF THE INVENTION

The present invention relates to apparatus for conditioning fuel for an internal combustion engine, and more particularly, to a fuel filter having a manually operable priming pump.

The practical necessity for conditioning fuel drawn from a fuel tank, prior to introduction into an internal combustion engine, is well known, particularly in diesel systems. One example of a known fuel conditioner is described in U.S. Pat. No. 4,491,120 "Fuel Conditioner". The unit described in that patent includes a manually operable priming pump mounted on the base or frame of the unit, to facilitate priming of a fuel system after a filter cartridge has been changed or the occurrence of exhaustion. The priming pump also provides a convenient means for expelling water. The priming pump described therein, includes a plunger type actuation, by which the user pushes down on a rigid disk, which advances a push rod, which in turn activates a diaphragm or the like to produce the required pumping action.

SUMMARY OF THE INVENTION

It is an object of the present invention to simplify and reduce the cost of manufacturing a fuel conditioner unit having a priming pump.

This object is achieved in accordance with the invention by utilizing the pump diaphragm member as the pump manual actuating surface. The preferred material which has the desired properties of flexibility and rigidity, is a material made of elastomer and plastic. The diaphragm is mounted to the basin portion of the priming pump, so that it has a convex, projecting dome surface adapted to be pushed by the user. A spring associated with the basin, biases the diaphragm outwardly, so that it can recover after each downward push by the user.

The priming pump basin, and suction and discharge legs are preferably integrally formed at the upper portion of the unit frame or base. In another cost saving embodiment of the invention, the frame is made of molded plastic rather than cast metal. An opening or archway is formed between the section and discharge legs of the priming pump. The plastic frame is sandwiched between the filter housing and a steel bracket, with spring clips passing from the bracket through the archway and into retaining engagement with the housing. The anchor points on the bracket and the housing do not stress the plastic frame, and thus avoid long term deformation resulting from creep.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the invention are described more fully below with reference to the accompanying drawings, in which:

FIG. 1 is an exploded view of the fuel conditioner in accordance with the preferred embodiment of the invention;

FIG. 2 is a side view of the frame assembly including the priming pump basin;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a section view taken along line 4--4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows an exploded view of a fuel conditioner 10 in accordance with the present invention. The unit is formed from three basic components, a frame assembly 12, a filter housing 14, and a bracket 16. As also shown in FIGS. 2-4, the frame assembly 12 is preferably made of molded plastic, in the form of a base 17 having a priming pump 18 extending therefrom. The base portion 17 of the frame 12 is generally rectangular, with top 20, bottom 22, front 24, and back 26 exterior surfaces. One side 28 of the base 17 is adapted to receive the filter housing 14, whereas the mounting side 30 is adapted to engage the bracket 16.

Inlet port 32 is formed on the front 24 of the base 17, and leads to integral conduit 34, which in turn is fluidly connected to a vertically extending, integral suction leg 36 for the priming pump 18. An integral discharge leg 38 leads from the pump 18 to integral conduit 40, which projects from the filter side 28 of the frame into the housing 14. Similarly, conduit 42 projects integrally from the filter side 28 of base 17, and leads to the outlet port 44, which projects integrally from the front 24 of the base. A water sensor 46 may also be mounted in the base to project therefrom. Drain conduit 48 leads to drain port 49 for manual draining. Optionally, a constant drain orifice can be provided at location 50 above the water sensor 46. A vent conduit 52 and associated vent port 54 are integrally formed in upper front portion of the frame.

In a manner known in this field of technology, the filter housing 14 is substantially self sealed except for holes (not shown) which are adapted to sealingly pass over and engage the conduits 40, 42, 48, and 52, and sensor 46, which project from the filter side 28 of the frame 17. The ports and conduits associated with the frame are preferably integrally formed therein, and may be located on or within the frame in positions other than those shown in the Figures, e.g., the inlet and outlet ports could be located as shown in phantom at 32' and 44', respectively.

The suction leg 36 and discharge leg 38 are preferably vertically oriented and laterally spaced apart, thereby forming an archway 56. The upper portions of the suction and discharge legs 36 and 38 open into a cup-like basin 58 in which suction opening 60 is formed in socket 61, and discharge opening 62 is formed in socket 63. A one way suction valve 64 and associated washer 66 and retaining ring 68 are mounted in the suction socket 61, and, similarly, one way discharge valve 70 and associated washer 72 and retaining ring 74 are mounted in discharge socket 63. The valves 64, 70 are arranged so that valve 64 opens only when the pressure in the basin 58 is lower than that in the inlet port 32 and inlet conduit 36, whereas the discharge valve 70 opens only when the pressure in the basin 58 is greater than the pressure in the discharge conduit 40. It should be appreciated that the fuel entering the unit 10 thus passes through a passageway that begins with the inlet port 32 and extends along conduit 34 to the suction leg 36, through basin 58, down discharge leg 38 into the housing 14, through the filter or other conditioning elements contained in the housing chamber (not shown), whereupon the conditioned fuel leaves the housing 14, passes through conduit 42, and is drawn from the unit 10 through outlet port 44.

The upper rim 76 of the basin is substantially circular and adapted to provide a mating surface for the circular lower rim 78 on diaphragm 80. A spring 82 is interposed between the floor 84 of the basin 58 and the diaphragm 80, thus assuring that the diaphragm maintains a convex, outwardly projecting crown surface 90. The diaphragm 80 is secured to the upper rim of the basin, by a sheet metal ring 86 crimped to hold the diaphragm in sealing engagement with the rim. The rim can have a lip 88 to improve the effectiveness of the crimp seal.

The diaphragm 80 can be made of rubber, or preferably an elastomeric and plastic material such as is available under the trade name Hytrel from Dupont. This affords a good combination of flexibility and rigidity so that the diaphragm itself can be used as the actuating surface upon which the user presses. If desired, the crown portion 90 of the diaphragm can be reinforced, as by a plastic plate, to reduce the unit load of the spring force against the diaphragm. The spring assures that the diaphragm recovers to its convex position after each manual actuation.

When the frame 12 is made of molded plastic, significant stresses on the frame should be avoided to prevent long term creep and thus deformation. Conventionally, the frame would include provision for the mounting of clips, by which the housing 14 could be secured to the frame. In accordance with another feature of the present invention, the frame base 17 is sandwiched between the filter housing 14 and metal bracket 16, with the bracket 16, not the base 17, providing one anchor point. Thus undesirable stress loadings associated with the retaining action of the clip on the housing 14 are avoided. In the illustrated embodiment, the bracket has an elongated portion 92 and a bent short portion 94. The long portion includes upper and lower ears 96, 98. Ears 96 align with archway 56, so that the associated upper clip 100 passes through the archway and engages the filter at notch 102. The lower clip 104 is pivotly mounted to lower ears 98 and can swing unobstructed around the bottom 22 of base 17, into engagement with notch 103 on housing 14. Holes 106 can be provided for receiving split fingers 116 on the mounting side 30 of base 17, to facilitate handling of the bracket 16 and frame assembly 12 as a subassembly when the housing 14 is removed. Holes 108 are provided in the short portion 94 for mounting the unit 10.

It should be appreciated that the details and options associated with the fuel conditioning within the filter housing will not be described in detail. The water level sensing, manual draining, and continuous draining, along with air venting, can readily be accomplished from the passageways and ports shown in the various figures. Optionally, vent plug 110 and drain plug 112 can be provided for selective venting and draining. Similarly, bracket 16 can be provided with a mounting seat 114 for the water level sensor 46, and associated electronics.