Fuel-filtering device

Abstract

A fuel-filtering device includes a filter body having a bag shape and a communication hole, and is formed of a plurality of laminated filter layers bonded at rim portions by welding. The laminated filter layers include an outside filter layer formed of a woven mesh, an inside filter layer formed of a non-woven fabric, and at least one intermediate filter layer disposed between the outside filter layer and the inside filter layer and formed of a non-woven fabric. The inside filter layer has an average aperture diameter larger than that of the intermediate filter layers. The filter body is formed of at least one of a polyethylene fiber and a polypropylene fiber. The inside filter layer protects the intermediate filter layer and enhances a weld strength at the rim portions.

1 . A fuel-filtering device to be disposed inside a fuel tank for filtering a fuel, comprising:
 a filter body having a bag shape and a communication hole, and being formed of a plurality of laminated filter layers bonded each other at rim portions thereof by welding, said laminated filter layers including an outside filter layer formed of a woven mesh, an inside filter layer formed of a non-woven fabric, and a plurality of intermediate filter layers disposed between the outside filter layer and the inside filter layer and formed of a melt blown non-woven fabric, said inside filter layer having an average aperture diameter larger than that of the intermediate filter layers, said filter body being formed of at least one of a polyethylene fiber and a polypropylene fiber,   wherein the inside filter layer protects the intermediate filter layer and enhances a weld strength at the rim portions.   
   
   
       2 . A fuel-filtering device according to  claim 1 , wherein said filter body is formed only of the polypropylene fiber having oil-water separation property. 
   
   
       3 . A fuel-filtering device according to  claim 2 , wherein said plurality of intermediate filter layers is formed of melt blown non-woven fabrics of polypropylene fiber and has mesh sizes decreasing toward the inside filter layer. 
   
   
       4 . A fuel-filtering device according to  claim 3 , wherein said outside filter layer is formed of the fiber with a diameter about 180 μm, said plurality of intermediate filter layers is formed of the fiber with a diameter between about 3 and 7 μm, and said inside filter layer is formed of the fiber with a diameter about 20 μm. 
   
   
       5 . A fuel-filtering device according to  claim 1 , further comprising a plastic cylindrical socket body having one end to be connected to a fuel suction port in the fuel tank and the other end connected to the communication hole. 
   
   
       6 . A fuel-filtering device according to  claim 1 , further comprising a plastic contact section disposed at a bottom of the fuel-filtering device for contacting an inner wall of the fuel tank. 
   
   
       7 . A fuel-filtering device according to  claim 5 , wherein said filter body is formed of two sheet sections as a filter base material made at least of said two laminated filter layers, said two sheet sections of the filter base material being bonded together at the rim portions thereof to thereby form the bag shape, said two sheet sections of the filter body being formed of two separate sheets or one sheet folded in half, said cylindrical socket body being a part molded by an insert molding in which the filter base material is inserted in a mold before the rim portions are bonded. 
   
   
       8 . A fuel-filtering device according to  claim 6 , wherein said filter body is formed of two sheet sections as a filter base material made at least of said two laminated filter layers, said two sheet sections of the filter base material being bonded together at rim portions thereof to thereby form the bag shape, said two sheet sections of the filter body being formed of two separate sheets or one sheet folded in half, said plastic contact section being a part molded by an inset molding in which the filter base material is inserted in a mold before the rim portions are bonded. 
   
   
       9 . A fuel-filtering device according to  claim 1 , further comprising a spacing member arranged inside of the filter body to maintain the bag shape. 
   
   
       10 . A fuel-filtering device according to  claim 1 , wherein said plurality of intermediate filter layers consists of a first intermediate filter layer arranged adjacent to the outside filter layer, a second intermediate filter layer arranged adjacent to the first intermediate filter layer, and a third intermediate filter layer arranged between the second intermediate filter layer and the inside filter layer. 
   
   
       11 . A fuel-filtering device according to  claim 10 , wherein said first intermediate filter layer is made of a polypropylene fiber with a diameter of about 7 μm, said second intermediate filter layer is made of a polypropylene fiber with a diameter of about 5 μm, and said third intermediate filter layer is made of a polypropylene fiber with a diameter of about 3 μm.