GB777001A - Slurry feeder - Google Patents

Abstract

777,001. Mixing apparatus. BOWSER, Inc. March 3, 1955 [March 22, 1954], No. 6364/55. Class 86 [Also in Group I] The supply of filter-aid slurry is controlled during a predetermined portion of a time cycle by means preferably comprising a solenoid valve operated by a process timer. The dial (not shown), of a process timer 27, Fig. 1, is set to that percentage of one complete cycle of the . timer during which it is desired to feed filter aid, such setting effecting adjustment of a movable cam 177 in relation to a fixed cam 175. Where the percentage is 50 or less a selector switch 29 is moved to the upper (28) position so that the circuit of a solenoid-operated control valve 109 is closed by contacts 187 so long as a cam follower 183 engages the gap between the high portions of the cams 175, 177 (which gap may extend for up to half the cycle). Where the percentage is above 50 the switch 29 is moved to the lower (30) position so that the circuit is closed by contacts 189 so long as a cam follower 185 engages the high portion of either cam. While the valve 109 is open some of the liquid to be filtered being pumped (33) from a tank 36 along pipes 48 and 50 to a filter 59 is by-passed along a branch line 72 spanning a throttle valve 47, the branch-line flow being along pipes 71, 75, 91 and 95. Between pipes 75 and 91 is incorporated an eductor (a nozzle-and-venturi device) whose suction connection with a slurry tank 11 is governed by the solenoid valve 109. Thus the feed of slurry is intermittent during filtration. The valve 47 may be replaced by a pump in the branch line. In Fig. 3 (not shown), the pump 33 occupies the position formerly occupied by the valve 47, which is dispensed with. Pre-coating is effected by slurry derived from the tank 11, while in Fig. 1 a separate pre-coat vessel 131 is provided.