Patent GB-1381239-A (GB)
Title: Liquid suspension purifying unit
IPC: B04C5/18
Filed: 1973-03-14
Abstract: 1381239 Hydrocyclones K R W ROBINSON 14 March 1973 [16 March 1972 25 Aug 1972] 12221/73 Heading B2P A liquid purifying unit, e.g. for purifying fibre suspensions for paper making, comprises one or more tapered hydrocyclones 30, Fig. 1, mounted in a housing 10, which by means of partition walls 24, 26, is divided into an inlet or inject chamber 12 in which the inlet 45 at the base of the or each hydrocylone is located, an accept chamber 16 into which the accept outlet 35 of the or each hydrocyclone discharges, and a reject chamber 20 into which the reject outlet 55 of the or each hydrocyclone discharges, the or each hydrocyclone being arranged vertically with its accept outlet 35 at the bottom and its reject outlet 55 at the top. The chamber 20 has a transparent plastics cover 28. Each hydrocyclone comprises a slightly conical casing 32 of stainless steel into the inlet end of which projects a cover element 34, Fig. 4, which is secured in an opening in the wall 24 by means of a eirclip 40 and is sealed against the wall by an O-ring 42. The element 34 has a central reject passage 36 leading to the reject outlet 35. The inlet 45 is tangentially formed by cutting out a flap in the hydrocyclone casing and folding- it. The narrowest portion of the casing 32 extends through an opening in the wall 26 to which is welded an externally threaded sleeve 46, Fig. 3, onto which is screwed a plastics outlet cone 50 engaging the upper end of the casing 32 over a padsing ring 52. A nozzle 54 terminating into the reject outlet 55 is secured by a screw joint 53 to the upper end of the outlet cone 50. As shown in Fig. 5, a number of units may be mounted on a base frame 56 with the inject, accept and reject chambers 12; 16 and 20 respectively connected via stubs 14-14', 18-18' and 22-22' to common inject, accept and reject lines 62, 60 and 64 respectively. Shut-off valves may be mounted on one or both sides of couplings between corresponding stubs to enable a unit to be shut off and disconnected without disturbing the remainder of the system. The units may be moved by means of a fork-lift truck or may be mounted on wheels. The reject chamber 20 of each hydrocyclone may be connected via a weir or, as shown in Fig. 5, over a pipe bend 70 forming a water trap for maintaining the liquid level in the chamber at X-X, Fig. 1, so that the reject is discharged above the water level and any blockage of the reject. outlets 55 can be observed through the cover 28. Another embodiment, Figs. 7-9 (not shown) having a more compact inject chamber, a longer reject chamber and a clamping device of different design for each hydrocyclone is described. In afurther embodiment, Fig. 12, a elutriation chamber 110 is arranged between the inject chamber 12b and the reject chamber 20b. Diluent, e.g. water, fed to the chamber 110 from a supply pipe flows into the outlet cone 80 of each hydrocyclone through a tangential inlet 132 where it mixes with the reject to facilitate discharge thereof and prevent, blockage of the respective reject outlet. In an alternative arrangement, Fig. 7 (not shown), the diluent may be tangentially fed to each hydrocyclone by means of a hose.