Patent GB-370564-A (GB)
Title: Improvements in and relating to the separation of carbonaceous materials, especiallycoal
IPC: B03B5/38
Filed: 1931-02-12
Abstract: 370,564. Washing granular materials. CLEAN COAL CO., Ltd., LESSING, R., and GYNGELL, E. S., Medway House, Horseferry Road, Westminster. Feb. 12, 1931, No. 4385. [Class 82 (ii).] Carbonaceous material such as coal is separated into components of different specific gravities by treatment in a bath of liquid having a greater specific gravity than water so that the heavier components sink and the lighter float, the material being carried across the bath by a transverse current of the liquid and the heavier components which sink being divided into at least two fractions which are collected separately. Carbonaceous material from a hopper 13 passes to a shoot 2 which is connected to the upper portion of a separating tank 1 of rectangular section and having converging sides which contains the separating liquid, e.g. an aqueous solution of calcium chloride. A quantity of the separating liquid, preferably sufficient to ensure the complete immersion of the material, is supplied to the shoot 2 through a pipe 16 and the feed of material to the tank 1 is controlled by a valve 15 which may be a hinged plate 29 with an adjustable balance weight 30 or a star wheel rotated by means outside the shoot. The tank 1 may be divided longitudinally by a partition in which case two shoots, one on each side, with feed hoppers and control valves may be provided. The stream of liquid from the pipe 16 carries the material across the tank 1 at or below the surface of the liquid therein and the lighter components which float leave the tank at an outlet 3. The heavier components which sink are divided into two fractions by a transverse partition 4, the upper edge of which can be moved towards or away from the inlet either by moving the partition as a whole, or, preferably, by the provision of a hinged upper portion 5 with a curved end 7. The portion 5 is formed of two parts slidably connected so that the height of the partition can be varied, the height and angular position of the portion 5 being controlled by the provision of a pair of upwardly extending rods 8 joined by a handle 48 and attached to the upper extremity of the portion 5, the rods being connected to T pieces 9 and supported by balance weights 10 on chains 11 passing over pulleys 12. The rods 8 are connected to the T pieces 9 by bolts passing through the rods and through slots 32 in the cross members of the T pieces, the angular position of the portion 5 being adjusted by moving the rods along the slots. Slots 37 are provided in the legs of the T pieces to accommodate bolts which fasten the T pieces to the side of the tank 1 and by varying the position of the bolts in the slots the height of the upper edge of the portion 5 is adjusted. The components which sink are removed continuously or intermittently by bucket elevators 43 or scraper conveyers. The float is carried from the outlet 3 up an inclined table 19, part of which is formed as a sieve, to a discharge shoot 23 by a conveyer 20 comprising pusher plates 21 with flexible wipers 22. The liquid draining through the sieve to a chamber 24 passes to a tank 25 from which it is redistributed by a pump 26 to the pipe 16 and, if desired, to an inlet 17 in the tank 1 to produce an upward current in the tank. Some may be pumped to an overhead tank which is connected to an inlet 18 in the tank 1, the inlet 18 being controlled by a valve 27 which is automatically operated by the variations in the level of liquid in the tank 1. The controlling device may consist of an extension 44 from the wall of the tank with a spring-loaded diaphragm 45 which actuates the valve 27 through relay mechanism 50. Adjustable baffles may be provided in the upper part of the tank 1 to direct the stream of liquid and material in a downward direction.. Specifications 276,723, 282,874, 325,031, [all in Class 82 (ii), Washing granular &c.], 341,863, and 361,906 are referred to.