GB772286A - Plant for conveying granular or fragmentary substances, notably coal sludges, through hydraulic means - Google Patents

Abstract

772,286. Conveying solids in a liquid stream. HOUILLERES DU BASSIN DE LORRAINE Sept. 17, 1953, No. 25673/53. Class 102(2) A system for conveying granular or fragmentary substances, e.g., coal sludges in a pipe line comprises chambers 1 in which residual water from coal washing plant is decanted and the sludge loaded water is forced by a pump 2 to a classifier or grader 3, acting as a thickener decanter, from which a mixture of a concentration greater than that required is delivered by a diaphragm pump or hydro-ejector 4 to a preparatory vat 5. A regulating vat 6 is provided from which particles of a larger size are delivered to the preparatory vat 5 by a diaphragm pump 7. Water from a tank 10 is supplied to the preparatory vat 5 through a float controlled valve 13 and also to nozzles 16, 17 for agitating - the mixture; overflow of the liquid from the classifier 3 and the vat 6 is also directed to the vat 5. A pumping station 22 comprises a battery of single stage impeller pumps having a flat characteristic which may be connected in parallel or series parallel and delivers to the pipe line 26 and the mixture from the vat 5 may be fed into the suction or delivery 'of the pump. A gamma-ray direct or differential opacimeter 24a is provided to indicate the concentration which should be of an optimum value to prevent pidimentation. As a precaution against sedimentation, the pipe line 26 at its curved points has a radius of curvature such that the force of the mixture on the pipe does not exceed 1.1 times the force of gravity and the inclination, of the pipe does not exceed the angle of repose of the granular product in the wet state. Suitable drainage is provided for use in case of sedimentation.