Filter element having microporous membrane

A pleated filter cartridge for filtration of aqueous liquids comprising:

• (a) an end cap having hydrophobic thermoplastic sealing material therein;
• (b) a hydrophilic microporous nylon membrane in sheet form having a microporous filtering surface and a nonporous crushed border surface with substantially closed micropores;
• (c) a netting layer on one side of the membrane;
• (d) the membrane and netting layer being folded to form a pleated filter cartridge surface;
• and
• (e) the nonporous crushed border surface being partially inserted and thermoplastically sealed within the hydrophobic thermoplastic sealing material of the end cap, wherein no portion of the microporous filtering surface contacts the hydrophobic thermoplastic sealing material.

A cylindrical pleated filter cartridge for filtration of aqueous liquids comprising:

• (a) a pair of end caps having a hydrophobic thermoplastic sealing material therein;
• (b) a hydrophilic microporous nylon membrane in sheet form having a microporous filtering surface and a pair of nonporous crushed border surfaces with substantially closed micropores;
• (c) a netting layer on each side of the nylon membrane;
• (d) the membrane and netting layer being folded to form a cylindrical pleated filtering surface;
• and
• (e) each of the nonporous crushed border surfaces being partially inserted and thermoplastically sealed within the hydrophobic thermoplastic sealing material of a respective end cap, wherein no portion of the microporous filtering surface contacts the hydrophobic thermoplastic sealing material.