Stitch knitted filters for high temperature fluids and method of making them

A dimensionally stable filter structure for removing foreign and particulate material from high temperature fluids comprising at least one batt of relatively brittle, high temperature and corrosion-resistant fibers, said at least one batt being made up of fibers chosen from the class consisting of glass fibers, silica fibers, ceramic fibers, carbon fibers and graphite fibers, said at least one batt being stitched-knitted with high temperature, corrosion-resistant yarns such that said filter structure comprises said at least one batt encapsulated between two outer stitch-knitted layers of said high temperature, corrosion-resistant yarns integrally connected through said at least one batt at a plurality of stitch-through points therein.