GB938569A - Improvements in or relating to pulp refiners - Google Patents

Abstract

938,569. Pulp dewatering and refining devices. DEFIBRATOR A.B. April 13, 1960 [April 16, 1959], No. 13169/60. Class 96. In a combined pulp-dewatering and refining device, pulp suspension from a bin 38 is pumped by a pump 40 under superatmospheric pressure through a conduit 42, controlled by a valve 44, into the inlet of a dewaterer 26 comprising a tube 28, having perforations 30 and surrounded by a casing 46, and housing a rotatable scraper device, e.g. a conveyer screw, 32, driven by a gear 36. Water expressed from the pulp passes through the perforations 30 and leaves the casing 46 via a valve 50 and a drain duct 48, whilst the pulp, e.g. increased in concentration from 5-6% to 10%, passes to a device 66 which creates a counterpressure in the dewaterer 26 by means of a conical valve body 68 acting against the pulp flow with a pressure determined by a servomotor 70 housing a piston 72 which is supplied at one or other side with liquid or gaseous fluid. The pulp then enters, via a duet 20, between stationary and rotating grinding discs 16, 12 and is withdrawn through a duet 22, controlled by a valve 24, to a flute 52 provided with sills 54, 56 and thence to a collecting bin 58, a pulp concentration testing device 65 located between the sills controlling the valve 50 whereby a variable further counterpressure is produced within the casing 46 which regulates the intensity of the dewatering operation and therefore controls the concentration of the pulp suspension entering the refiner with respect to that withdrawn from it.