| 摘要 |
642,556. Filters. THOMSON, W. R. Jan. 21, 1948, No. 1886. Convention date, March 6, 1947. [Class 46] liquid is separated from material containing liquid and solids by feeding the material to the upper surface of a horizontal endless suction mat, and moving the suction mat first in a horizontal direction over a stationary surface where the material is subjected to a relatively low degree of vacuum and then through an arc of a circle in contact with a synchrously-moving arcuate surface where the material is subjected for a part of its path to a relatively high degree of vacuum, the time for the low-vacuum stage being greater than that for the high-vacuum stage. As shown, an endless suction mat 22 of rubber or the like, with openings on its upper surface communicating with openings in its lower surface, first passes over perforated members 5 on two transverselyspaced series of adjoining suction-boxes 4 connected to a source of vacuum by pipes 7, independently controlled at 7', header 8 and pipe 9, the mat being supported by rollers 25, and together with an overlying filter screen 29 kept in contact with the boxes 4 by deckle straps 32. It then passes over a hollow drum 2 having annular perforated areas in alignment with the horizontal perforated members 5, and by means of these it communicates with arcuate suction-boxes 14 mounted on gudgeons 17 carried by springs 18 and connected to a source of vacuum by pipes 19, 20. The return portion of the filter screen 29 is carried by rollers 30, 31; the drum 2 is driven by a small gear wheel 38. A progressively increasing degree of vacuum from say 6 in. to 16 in. of mercury, from the first to the last pair of boxes 4, may be provided. On the drum 2 the vacuum may range from 20 in. to 26 in. of mercury, but should not exceed 30 in., or fall as low as 16 in. |
