GB561799A - - Google Patents

Abstract

561,799. Washing granular material. BLANTYRE ENGINEERING CO., Ltd., and KERR, W. Nov. 20, 1942, No. 16438. [Class 82 (ii)] A washer-box of the U-compartmented or Baum type for coal or other mineral is provided with a supplementary valve or valves for closing and opening a port at the air pressure side of the washer box 10 at a time of high water level in the washing compartment side 10a of the box, so that, when'the water has risen to or nearly to its maximum level in the washing compartment side of the box, the water column on that side will first be depressed and then restored to its high level before it begins its main descent. The supplementary valve or valves operate in conjunction with the main valve element to effect additional control of the air supply and/or the air exhaust. In one form of the apparatus, the main valve element 12 is operated by an eccentric 13 within a valve chest 14 having an inlet port 15 and exhaust ports 16. Adjustably mounted on the piston rod 17 of the main valve 12 is a supplementary valve 18 which, when the water has risen to its topmost level within the washing compartment side 10a of the washer box, momentarily masks the air inlet port 15 whereby there is first produced a more or less abrupt fall of the water level followed by a rise of the water level in the washing compartment side 10a, this abrupt rise being followed by a continuous fall under control of the ports 15, 16 by the valve 12. In another arrangement the object in view may be realised by the employment of a sleeve valve performing combined axially reciprocating and oscillating movements ; or an inlet valve and a separate outlet valve may be provided.