referring now to fig1 an in - tank fuel filter assembly according to the present invention is illustrated and generally designated by the reference numeral 10 . the in - tank fuel filter assembly 10 is illustrated disposed adjacent the bottom wall 12 of a vehicle fuel tank 14 . the vehicle fuel tank 14 is conventional and representative of the general class of vehicle fuel storage enclosures with which the present invention will be utilized . as such , it includes an inlet tube 16 for facilitating supply of fuel to the fuel tank 14 and an outlet fitting 18 through which a fuel line 20 sealingly extends and fuel may be withdrawn . referring now to fig1 and 3 , the fuel filter assembly 10 comprises a fabric swatch 24 and a fuel line fitting 26 the material of the fabric swatch 24 may be nylon , saran polyester , polyvinyl chloride or copolymers of polyvinyl dichloride . saran is a registered trademark of the dow chemical company . while the fabric swatch 24 will typically be homogeneous , that is , comprehend a fabric of monofilament warp and woof threads of the same material , it is also within the scope of this invention to utilize a fabric comprehending warp threads of one material ( e . g ., nylon ) and woof threads of another material ( e . g ., saran ), to utilize multifilament threads as well as monofilament threads and any combination of the above variables . the fiber or thread size and size of the interstices between fibers of the fabric swatch 24 may vary widely over appropriate ranges to provide filtration of selected sizes of undesirable particulates . typically , interstitial opening sizes of 60 to 100 microns provides suitable particulate filtration of hydrocarbon fuels intended for use in internal combustion engines . fiber or thread size is typically in the range of 0 . 004 to 0 . 008 inches and is preferably from about 0 . 0055 inches to 0 . 007 inches depending on the material and desired characteristics of the fuel filter assembly 10 . the fabric swatch 24 may be folded upon itself along a fold line 28 and sealed by ultrasonic bonding , chemical solvents or other means along a longitudinal seal 30 and along transverse seals 30a extending across the ends of the fabric swatch 24 . disposed within the fabric swatch 24 of the fuel filter assembly 10 is a porous insert 34 . the porous insert 34 maintains the upper and lower walls of the fabric swatch 24 of the fuel filter assembly 10 in spaced configuration to facilitate fuel flow between and into the fuel line fitting 26 while providing minimal flow resistance . the porous insert 34 may be any suitable size wrapped or rolled swatch of nylon , saran or other fabric or may be extruded polypropylene netting having , for example , a generally cylindrical cross - section in pre - assembly configuration . referring now to fig4 the fuel line fitting 26 includes an upper fuel line segment or fitting 40 and a mating lower fuel line segment or fitting 42 . the upper fuel line fitting 40 is preferably circular and defines a concentrically disposed circular through aperture 44 . a first portion 44a of the through aperture 44 defines the smallest diameter region . generally medially axially disposed within the first portion 44a of the through aperture 44 is a reentrant circumferential channel 46 . the circumferential channel 46 receives and retains a flexible metallic retaining ring 48 . the retaining ring 48 defines a concentric circular aperture 50 which receives the fuel line 20 and tightly frictionally retains the fuel line 20 within the upper fuel line fitting 40 as illustrated in fig1 and 6 . the upper fuel line fitting 40 also includes a first , radially extending shoulder 54 and adjacent reentrant axially extending recess or channel 56 . the through aperture 44 further includes a second , larger diameter region 44b which extends axially from the channel 56 to a second , radially extending shoulder 58 . finally , the through aperture 44 includes a third , largest diameter region 44c . the lower face of the upper fuel line fitting 26 defines a circumferential , convoluted surface 60 . the lower fuel line fitting 42 is also preferably circular and defines a centrally disposed through aperture 64 which also receives the fuel line 20 as illustrated in fig6 . the through aperture 64 is preferably the same diameter as the first portion 44a of the through aperture 44 . the lower fuel line fitting 42 defines a frusto - conical face 66 . the frusto - conical face 66 has an upper , smaller diameter adjacent the upper face of the lower fitting 42 which is preferably slightly less than the diameter of the second , larger diameter region 44b of the through aperture 44 and has a lower , larger diameter approximately equal to the third , largest diameter region 44c of the through aperture 44 . the lower fuel line fitting 42 includes a radially extending flange 68 having a convoluted surface 70 which aligns with the complementarily convoluted surface 60 of the upper fuel line fitting 40 . as illustrated in fig4 in pre - assembly configuration , the upper and lower fuel line fittings 40 and 42 , respectively , are generally disposed and aligned on opposite sides of the fabric swatch 24 in which a circular aperture 72 has been formed . referring now to fig5 the fuel line fitting 26 is shown during the ultrasonic bonding assembly step . as such , the upper fuel line fitting 40 is bonded to the lower fuel line fitting 42 by the application of ultrasonic energy and compressive force . the ultrasonic energy is applied by a horn 74 which is the output and application component of an ultrasonic bonding machine ( not illustrated ). the horn 74 is circular and uniformly applies ultrasonic energy and mechanical force to the fuel line fitting 26 as those familiar with such bonding techniques will readily appreciate . as the assembly and bonding process occurs , the shoulder 58 shaves and deforms the material of the lower fuel line fitting 42 in the region of the frusto - conical surface 66 . to a lesser extent , the frusto - conical surface 66 causes deformation and flow of the material of the upper fuel line fitting 40 . the flow of such dislodged material forms a bead 78 which appears as the irregular shape in the cavity generally adjacent the shoulder 58 . this bead 78 is a flow of dislodged material melted by the ultrasonic energy applied by the horn 74 . as the upper and lower fittings 40 and 42 , respectively , of the fuel line fitting 26 are compressed against one another , the molten material collects and flows toward the fabric swatch 24 , forming the bead 78 . referring now to fig6 the final configuration of the fuel line fitting 26 is illustrated . here , the upper fuel line fitting 40 is fully seated against the lower fuel line fitting 42 . as such , the mating circular convoluted surfaces 60 and 70 are compressed against and retain the fabric swatch 24 . more importantly , however , the bead 78 of dislodged material formed by the ultrasonic bonding process has generally filled the cavity adjacent the shoulder 58 , filling the interstices in the fabric swatch 24 . when the material 78 cools and hardens , the fabric swatch 24 is mechanically bonded and locked within the fuel line fitting 26 by virtue of such material flow . the upper fuel line fitting 40 and the lower fuel line fitting 42 are , of course , securely bonded together along the interface 80 . any molten material that flows upward along the interface 80 toward the first portion 44a of the through aperture 44 is received within the channel 56 . the channel 56 acts as a trap to prevent the flow of melted material into the apertures 44 and 64 which receive the fuel line 20 . the preferred method of assembly of an in - tank fuel filter 10 according to the present invention comprehends the following steps . first of all , the upper and lower fuel line fitting 40 and 42 are molded by processes such as injection molding of a suitable plastic material such as nylon , acetal resin , or similar plastic or elastomer . the retaining ring 48 is then inserted in the circumferential groove 46 of the upper fuel line fitting 40 . the fabric swatch 24 is cut to size and the aperture 72 formed therein through a process such as ultrasonic cutting . next , the upper fuel line fitting 40 and lower fuel line fitting 42 are loaded into the ultrasonic bonding machine on opposite sides of the fabric swatch 24 and in alignment with each other and the aperture 72 , as illustrated in fig4 . the ultrasonic horn 74 then engages the upper surface of the upper fuel line fitting 40 as illustrated in fig5 . both axial force and ultrasonic energy are applied to the fuel line fitting 26 , melting the material and forcing the fittings 40 and 42 together . during the bonding process , the formation of the bead 78 of material occurs and the fabric swatch 24 is compressed between the convoluted surfaces 60 and 70 . as noted above , the bead 78 of dislodged material engages the marginal edge of the fabric swatch 24 at the aperture 72 and adjacent fabric , cools and tightly retains it within the fuel line fitting 26 . upon completion of the ultrasonic bonding step , the longitudinal seam 30 , illustrated in fig3 may be accomplished by any suitable sealing technique such as radio frequency ( rf ) sealing , ultrasonic bonding , sewing or the use of chemical solvents or glues . next , the porous insert 34 is stuffed into the interior of the fabric swatch 24 , also as generally illustrated in fig3 . finally , the remaining transverse seals 30a of the fuel filter assembly 10 are accomplished by one of the techniques listed directly above . the in - tank fuel filter assembly 10 according to the present invention is now complete . the foregoing disclosure is the least mode devised by the inventor for practicing this invention . it is apparent , however , that devices and methods incorporating modifications and variations will be obvious to one skilled in the art of fuel filters . inasmuch as the foregoing disclosure is intended to enable one skilled in the pertinent art to practice the instant invention , it should not be construed to be limited thereby but should be construed to include such aforementioned obvious variations and be limited only by the spirit and scope of the following claims .