Patent GB-391269-A (GB)
Title: Improvements in apparatus for screening and washing granular materials
IPC: B03B5/56
Filed: 1932-01-23
Abstract: 391,269. Washing granular materials. PARKER, WINDER, & ACHURCH, Ltd. and SMITH, W. H., Broad Street, Birmingham. Jan. 23, 1932, No. 2106. [Class 82 (ii).] An apparatus for screening and washing granular material comprises a rotary body, having peripheral screening sections of varying coarseness, with the section adapted to screen the finest material of larger diameter than the remainder of the body, and having its lower portion disposed in a tank containing water, a mechanical scraper being provided for removing the sand, &c. that passes through the portion of the body disposed in the tank. The screen body is mounted on a central shaft 17 carried on a framework, and is supported on spiders 77 and an intermediate spider 78 which engages an imperforate sleeve 79. The material is charged from a hopper 45, fed by hand or by a bucket conveyer 47 into the end 19 which comprises fine mesh grids 21 through which the fine material is screened into a tank 22. Water from a perforated pipe or pipes 80 may be sprayed over the charge. As the screen body rotates, inclines or bevels comprising fine grids or screens 38 formed as a spiral, raise the coarse material retained by the screens 21 and deliver it into the remaining sections 48, 49 of different coarseness. Inclined shoots 51, 52 direct the material passing through these screen sections to different sides of the body. The final grade of material is rejected entirely from the body. The grids 38 slide in guides 40, secured to an annular end disc 41 at the end of the first portion of the body and to a baffle plate 42 at the other end of the grids. The baffle-plate 42 prevents the materials fed into the first portion from passing directlv to the remainder of the body without being operated on by the first portion. The material moves round the spiral of grids until it reaches the last grid at which an inclined baffle-plate 39 directs it into the remaining part of the body. The grids may be removed from the guides when necessary, and each grid is secured in position by a strip 43 overlapping one end of the grid, the other end of the grid being retained in the angle of an iron 44. The tank has a drain cock 28 and an inclined side 23, which, like the bottom, may be formed of removable plates. An inlet pipe, and outlets with removable plugs 30 provide any desired water level. The mechanical scraper comprises blades 24 connected by chains 25 and removes the sand over the edge 31. A sprocket 26 is adjustably mounted on the frame to adjust the tension in the chains. Each blade comprises a member having its upper and lower sides open, and its front 34 and back 35 perforated, whilst portions of the end walls 37 are pressed outwardly. Each blade is attached between the chains by studs passing through apertures 36 in the end walls. The screen is rotated from an engine or motor through a belt 58 and pulleys, a dog clutch operated by a handle 61 connecting the drive with a transverse shaft 63 gearing with the main central shaft, and driving also a transverse shaft 67 gearing with a third shaft 70 for driving the mechanical scraper. The bucket conveyer is driven from the shaft 67 through chains 71, 74 and a spindle 73 supported on adjustable bearings 76.