Porous wall structure and method of manufacture

摘要

939,963. Wire fabrics. BENDIX CORPORATION. May 17, 1960 [June 22, 1959], No. 17398/60. Class 74 (2). [Also in Groups I, XII, XXI, XXII, XXVI, XXVIII and XXXIV] A wire fabric for providing a porous wall structure for filters, bearings, reactor cores, heat exchangers, rocket motors, nozzles, missiles, nose cones, turbine blades afterburners and combustion chambers comprises a layer one wire thick of alternate smooth wires 14, Fig. 1A, and wires 16 with helical protuberances thereon. The wires 16 may be formed by twisting plane-faced wires or may be of stranded cable and are bonded along their entire length to the wires 14. The wires may be of steel, copper, titanium or molybdenum or alloys and the bonding may be effected by (1) direct fusion, (2) fusion after coating with tin, silver, copper, gold, tin-lead alloys or copper-silver alloys, (3) fusion after applying a brazing powder, (4) fusion after applying an easily reductible oxide such as CuO, CuO 2 or AgO, (5) including a fine wire of brazing material in the fabric layer and fusing, (6) by dipping in a molten bath of tin, copper, plastic or other bonding material. The wires may also be of plastic or any other material connectible by fusing, gluing or other suitable means. A figure of revolution may be formed by winding the wires under tension on a suitable former, such as a cylinder, which may afterwards be cut and formed into a flat sheet. If desired, other layers of the fabric may be added to a first layer as in Fig. 2 and a nesting effect may be obtained if the wires 14, 16 are of different diameters, to reduce the porosity of the structure. If desired, however, the layers may be wound of alternately different hands. The fabric may also be bonded to the mandrel upon which it is wound such as a perforated cylinder 26, Fig. 6, or a fluted cylinder 28, Fig. 7, for added strength and for use as filter elements. The porous fabric cylinder may be further subjected to rolling after heat treatment to compact it further to reduce the porosity. This may be carried out on the mandrel or if the mandrel is ceramic the fabric cylinder may be removed for this operation. A second heat treatment may then be applied.