Patent ID: 7404493

Claim:
A filter device without a perforate outer cylinder sleeve that supports the outer periphery of a cylindrically formed pleated filter, said filter device comprising: a cylinder portion having a cylindrical internal space with both ends open, said cylinder portion having an upper end, and said cylinder portion having a lower end, said cylinder portion has a tapered inner surface that is divergent toward the upper end of the cylinder portion to form a gas collection passage defined by the tapered inner surface of cylinder portion and an outer periphery of a cylindrically formed pleated filter, said gas collection passage communicated with a vent passage, the lower end portion of the cylinder portion has a thin wall portion through which guide grooves pass; said cylindrically formed pleated filter inserted in the cylindrical internal space of the cylinder portion, said cylindrically formed pleated filter in contact with an inner surface of the cylinder portion said cylindrically formed pleated filter having upper and lower edges liquid-tightly sealed; a gas vent port that discharges gas collected in said gas collecting passage; a perforate inner core supporting an inner surface of the pleated filter, said perforate inner core having an upper end and a lower end, said perforate inner core has a plurality of radial passages of outwardly divergent sections; a lower end cap liquid tightly bonded to the lower end of said cylinder portion and an upper end cap liquid-tightly bonded to the upper end of said cylinder portion; the upper end of said cylindrically pleated filter, the upper end of said perforate core, and the upper end of said cylinder portion are bonded to a lower surface of said upper end cap, and wherein said cylinder portion, said lower end cap, and said upper end cap are welded together to form a liquid tight housing; an annular liquid distribution passage communicating with gaps between pleats in a lower end of the cylindrically formed pleated filter, said annular liquid distribution passage formed between the lower end of the cylinder portion and lower outer periphery of said cylindrically formed pleated filter; a liquid feed passage formed by spacing the lower end of the perforate core from an inner bottom surface of the lower end cap, said liquid feed passage communicates with the feed inlet and the annular liquid distribution passage, wherein said liquid feed passage is communicated with the gas vent port by way of a gas vent passage; a liquid feed inlet communicating with the annular liquid distribution passage; a filtrate liquid withdrawal passage communicating with an internal passage of the perforate core; and a filtrate outlet communicating with the filtrate liquid withdrawal passage.