Method for manufacturing refractory material having numerous through pores extending in a certain direction

Claim 1

In a method for making a shaped article of a refractory material suitable for contact with molten metal, said shaped article being the type wherein a refractory material in paste or slurry state is contacted with a woven fabric and the thus contacted fabric and refractory material are laminated into the desired shape and the liminate preform block thus obtained is heated to dry the block and to burn off the combustible fibers of said fabric and then fired to sinter said refractory material, the improvement which comprises at least one of the weft fibers or the warp fibers of the woven fabric being combustible and said combustible fibers having a diameter between 40 to 300 microns, and wherein a vibration between about 900 to 10,000 Vpm and an amplitude of 0.1 to 1.0 mm is applied to said woven fabric in said laminating step to remove air bubbles from and increase the uniformity of the laminate, and the combustible portion of the fabric is removed by said heating to produce a multiplicity of pores extending through said shaped refractory article corresponding to the thus removed fibers and wherein prior to the burn off, the surface of the body which is parallel to the through pores is temporarily covered with an insulating layer, leaving the end faces perpendicular to the through pores uninsulated and wherein the burn off is carried out by applying heat to the uninsulated end faces so as to exhaust the gas produced by the combustion of the fibers and produce smooth escape of the gas and avoid pressure buildup, and then removing the temporary insulating layer.