Patent GB-1108943-A (GB)
Title: A machine for treating, separating and/or pumping fluid mixes
IPC: F04D11/00
Filed: 1965-04-07
Abstract: 1,108,943. Filters for liquids; centrifugal strainer separators. G. NEIDL. 7 April, 1965 [7 April, 1964], No. 14822/65. Heading BID. [Also in Division F1] In a pump and strainer assembly comprising a stationary pump housing formed by walls defining a pump chamber therein and an impeller rotating in the housing, a drive shaft for the impeller extending axially into the housing, the impeller being inclined to the shaft, a shell is provided enclosing at least part of the pump housing, the shell forming with the walls of the pump housing a separate chamber, strainer passages connecting the pump chamber and the separate chamber, an inlet for the pump chamber, an outlet for the separate chamber, and an outlet for the pump housing passing through the separate chamber. As shown in Figs 1 and 1a, a mixture is introduced at 9; heavier solids are thereafter ejected through spigot 4 and pipe 5 by centrifugal force exerted by rotation of the elliptical impeller 1; solids too large to pass through apertures 6 are also discharged through 4, 5. Remaining solids and liquid pass through apertures 6 and are discharged at 8. The discharge openings 5 and 8 may be partly closed to promote extended treatment. Shaft 2 may be hollow and may be externally heated and impeller 1 may be hollow and perforate. Chemical agents or detergents, and heating agents (e.g. steam) may be supplied through the hollow shaft. The material issuing at 4, 5 may be returned at 9. The material issuing at 8 may be returned either at 9 or through the hollow shaft 2. In Fig 2. two impellers 14, 15 rotate on a common shaft 19. The impeller 14 and a partition 16 are perforate to permit material to pass from inlet 13 to impeller 15. Partition 16 may be omitted. The elliptical impeller 14 may be replaced by a circular impeller, which need not then be perforated.  In an alternative arrangement two devices as in Figs 1, 1a are used in series, the filtrate from the first being introduced at the entry 9 of the second. The materials discharged at 5 from the two devices are preferably kept separate, but that from the first device may be re-mixed with the filtrate introduced at the entry 9 of the second device. The impeller orientations of the two devices may differ in phase by 180‹.  The interior housing 3 of Figs 1, 1a may be frusto-conical and the impeller then takes the form either of two diametrically-opposed shoes at the ends of a rod oblique to shaft 2, or of a frusto-conical closed ring obliquely disposed.  The edges of the impeller of Fig 1a may be toothed, and there may be apertures in the end walls of the housing 3 with which toothed ends of the impeller co-operate. These apertured portions are covered by appropriate extensions, with outlets, of shell 7. An apparatus of this kind may be located vertically in a hot air duct, which takes the place of the shell 7. Material, e.g. digested sludge from a clarification plant, is fed in at the upper end, and the concentrated sludge, discharged from a horizontal pipe extending through the duct wall, may be re-circulated. Filtrate, &c., passing through perforated wall 3 mingles with a downward current of hot air and is discharged with it. The impeller may be folded about a line oblique to the shaft 2, and the folded portions may be arcuate in cross-section instead of flat. The apertures 6 may have various shapes and be inclined in the direction of rotation of the impeller; the perforate surface may be covered with gauze or cloth filter elements.  Other materials which may be treated are as follows:-rags or mechanical wood pulp for papermaking, hops, baggasse, plastics, synthetic materials. In the last two cases the apparatus is immersed in a tank of the material, and re-circulation occurs in the tank.