| 摘要 |
999,562. Filters for liquids. GENERAL MOTORS Ltd. Sept. 10, 1963 [Sept 11, 1962; Jan. 16, 1963], Nos. 34612/62 and 1900/63. Heading B1D. The filter includes two filter elements: 2, Fig. 2, of finer porosity, and 3, of coarser porosity, made, e.g., of resin-impregnated filter paper ; a control device is arranged so that during an initial period of operation the proportion of the liquid passing through the "finer" element is greater than that which passes through the "coarser" element. In Fig. 2 the control device is the disposition of the holes in the perforate support tube 4: they are more numerous adjacent the "finer" element 2. In another embodiment, this disposition of holes is provided in a support tube surounding the filter. In Fig. 7 the finer element 22 and coarser element 23 are arranged end-to-end and the lower end of the internal space is closed. Initially liquid flows inwardly through 22 only, but on attainment of a predetermined pressure drop a valve 36 rises, permitting inward flow through 23 also. The valve may be replaced by a plate with a restrictive orifice. In Fig. 8 the elements are arranged as in Fig. 2, and the valve is a spring leaf valve 40. |
