| 摘要 |
1,260,746. Micro - filters. BRUNSWICK CORP. 29 Jan., 1969 [30 Jan., 1968], No. 5018/69. Heading B1D. Very small solid particles are filtered from a liquid by a filter element (Fig. 1) comprising an integral metal body structure having a pair of spaced apart surfaces 13 and a plurality of substantially rectilinear passages 12 each opening at the surfaces and having a maximum cross section dimension of under 25 microns; the maximum cross section dimension of each passage, at at least one point therealong, being reduced to under 10 microns by material attached to the structure, e.g. particles or a layer of metal or plastics material, e.g. polytetrafluoroethylene, deposited in the passages. The filter elements are formed by constricting a bundle of metal rods 15 (Fig. 7), each sheathed in a tubular metal sheath 16, by drawing the bundle through a die 18 to form a unified composite 19 (free from voids) wherein the sheaths define a matrix body 21 in which filaments 20 are distributed in parallel relationship; the composite 19 is then transverely cut into disc-like elements 23, and these are suitably treated to remove filaments 20 leaving the required filter passages. If the rods 15 are made of nickel-copper alloy and the sheaths 16 are made of stainless steel, the filaments 20 may be removed by immersing the disc elements 23 in nitric acid. The crosssection of the rectilinear passages may be reduced by sintering metal powder therein, or by forming a layer of metal partially across the upstream openings of the passages (Fig. 6, not shown) by electrodeposition. |
