Fuel tank dewatering apparatus

Claim 1

For use in conjunction with an engine fuel tank having a bottom and having an inlet therein for filling the tank with liquid fuel, the combination which comprises: (a) a substantially hollow and cylindrical submersible container adapted for insertion into and removal from the fuel tank through said inlet; (b) said container comprising an elongate, substantially rigid structural cage, which encompasses an elongate cylindrical volume, and a correspondingly cylindrical screen immediately encompassed by, contained within and secured to the cage; (c) the cage having a plurality of circumferentially spaced longitudinal ribs, a plurality of longitudinally spaced circumferential ribs, and opposite end closures, said ribs and end closures being joined together; (d) said cylindrical screen being secured within the confines of said spaced longitudinal and spaced circumferential ribs and providing porous wall portions of substantial extent exposed therebetween along the length and around the girth of the container and, in conjunction with the cage, defining a substantially open and fixed, approximately cylindrical internal volume; (e) elongate tie means for manually retrieving the container from the bottom of the fuel tank through said inlet, the tie means having proximate and distal end portions; (f) means for attaching the distal end portion of the tie means to the structural cage of the container; (g) means for releasably anchoring the proximate end portion of the tie means at an accessible location near said fuel tank inlet; (h) a dry volume of particulate hygroscopic material disposed inside the container and filling a minor portion of said fixed internal volume of said container, said hygroscopic material being expandable to many times said dry volume in the presence of water; (i) said exposed porous wall portions of the screen being permeable to air, water and to the liquid fuel, but substantially impermeable to the hygroscopic material; and, (j) the dry volume of said hygroscopic material in said container being selected to limit its fully expanded volume in the presence of water to a predetermined hydrated volume which substantially fills said fixed internal volume of the container without rupturing the container, or extruding the material through the porous wall portions of the container, whereby said container with the hygroscopic material therein may be inserted into and later retrieved from the fuel tank to remove water from the liquid fuel therein.