GB620133A - Improvements in and relating to the automatic control of the bulk density of particulate coal - Google Patents

Abstract

620,133. Coking-apparatus. KOPPERS CO., Inc. Jan. 1946, No. 88. Convention date, Aug. 18, 1945., [Class 55 (i)] [Also in Groups XXX and XXXV] The invention is concerned with maintaining a constant bulk density of a coal and liquid mixture fed to coke oven bins, and essentially consists in weighing a sample of the mixture and using the result to control the liquid discharged on the coal. Coal of different qualities is fed to breaker mills, e.g. 12, Fig. 1, and then to hoppers 13 to fall on endless belt 14 for mixing ; oil and water are supplied'from pipes 16, 17 so that the mixer 20 ejects an aggregate which is supplied over belt 22, Figs. 1 and 2, shoot 25, belt 26 to the coking oven 9. At intervals determined by a sequence timer, Fig. 3, a motor 30, Fig. 2, is energised .to move flap 28 to divert the coal delivered by belt 22 to shoot 37 for a.sufficient time to fill a box 38; arm 47 is then caused to level off the coal in the box, and the lock 46 is released to allow the box to be weighed on the beam 52. The motor 56 is then energized to open the bottom of box 38 and allow its contents to fall on belt 26 ; the registering pointer 55 of the weight indicator 23 moves over a resistance 63, Fig. 3, to control a follow-up device comprising a reversible motor 65 moving a resistance 75 over a contact 73. The motor 65 actuates the water control valve 62 over a reversible ratchet device 67, which is set to engage when the shaft 69 is rotated in one direction or the other by a relay 68 actuated by a mercury switch 72 mounted on the rotatable resistance 75 ; as a consequence, if the aggregate is light, the indicator 55 moves away from its central position and resistance 73 is rotated in one direction a corresponding amount, mercury switch actuates and the valve 62 is closed to an extent corresponding with the movement of resistance 75. If the next sample is less light, the motor reverses, but mercury switch 72 is not reversed, so that the valve 62 is not affected ; only when the sample is heavy does mercury switch 72 reverse to allow the valve 62 to be opened further. When valve 62 is completely closed, contacts 84 are closed to energise motor 80 and open the oil valve. In a modification, the weighing operation is performed on a part of the conveyer belt 22, Fig. 4 (not shown), so that the testing is continuous and the sequence timer unnecessary.