Abstract: A porous tubular element of uniform density and porosity is formed by uniformly depositing binder and crushable fibers selected from the group consisting essentially of polycrystalline, alumina, zirconia, aluminum silicate and potassium polytitanate fibers from an aqueous dispersion onto a cylindrical mold. The tubular element is then compressed with sufficient pressure to crush and rearrange the fibers to obtain uniform density and porosity.

Abstract: A process of preparing an inside-to-outside flow filter tube, which process comprises dispersing a plurality of glass fibers in water to form a water slurry of the fibers, the glass fibers having a diameter range of from about 0.001 to 10 microns; forming a filter tube comprising a wet mat of the glass fibers from the water slurry on a cylidrical mandrel; during the forming of the wet mat of fibers into a filter tube, incorporating an open-scrim, reinforcing sheet material within the internal wall thickness of the wet mat of fibers forming the filter tube, the sheet material extending generally the length of the filter tube and at least about 11/2 revolutions of the filter tube diameter; drying the filter tube containing the scrim sheet material within the filter tube wall; bonding the dried filter tube with a bonding agent at the junction of the glass fiber crossover points and with and through the scrim sheet material; and recovering an integral filter tube having a high burst strength.

Abstract: An improved inside-to-outside flow filter tube and method of manufacturing the tube, which filter tube comprises: a plurality of nonwoven fibers having interstices therebetween to define the porosity of the filter tube, the tube containing a binding agent at the junction of the fiber crossovers to provide a self-supporting structure of a defined wall thickness and filter porosity; and an open scrim reinforcing sheet material within the wall of the filter tube extending generally the length of the tube and at least one overlapping revolution about the tube diameter, the fibers of the filter tube bonded integrally through the open scrim material, thereby permitting the use of the filter tube in applications requiring inside-to-outside fluid flow without the necessity for an external peripheral support.

Abstract: A method of manufacturing an inside-to-outside flow filter tube and the filter tube so manufactured which comprises: providing a porous tube comprising a wet mat of randomly disposed glass fibers; positioning an external reinforcing sleeve material concentrically about the porous tube; applying an outward force to the porous tube to expand the external diameter of the porous tube into intimate contact with the sleeve material; and drying the tube and bonding the fibers of the tube into an integrally supported filter tube.

Abstract: A filter tube, which filter tube comprises a mass of interrelated nonwoven glass fibers, the fibers having a diameter of from about 0.001 to about 10 microns, the fibers bonded at the junctions of the fiber crossovers with a hardened silicone resin bonding agent, the fibers interrelated to form a semirigid mass of desired porosity suitable for use as a filter for gases or liquids.

Abstract: A filter tube, which filter tube comprises a mass of interrelated nonwoven glass fibers, the fibers having a diameter of from about 0.001 to about 10 microns, the fibers bonded at the junctions of the fiber crossovers with a hardened silicone resin bonding agent, the fibers interrelated to form a semirigid mass of desired porosity suitable for use as a filter for gases or liquids.