GB462199A - Improvements in or relating to settling tanks - Google Patents

Abstract

462,199. Gravity-separation apparatus. CALLOW, J. M. Dec. 7, 1935, Nos. 33989/35 and 15097/36. [Class 111] Rotary sludge scrapers 5 in a settling tank 2 are supported from a float 1 which is connected to travelling means so arranged and guided round the periphery of the tank that the float is constrained to keep at or about the centre of the tank. In the arrangement shown in Figs. 1 and 2, the wheels of a carriage 7 at the end of a driving arm 4 connected to the float 1 are driven by an electric motor 13, and those of a carriage 7<1> at the end of a scraper arm 3 are idle. The carriages 7, 7<1> are arranged to rock about vertical and horizontal axes and the position of the float can be regulated by means of liquid ballast 15, supplied or discharged by a pump 16, or by means of a counterweight 30 sliding on the arm 4. The lower part of the raking structure is provided with track wheels 17 which engage a track 18 and so prevent the scrapers from coming into contact with the floor of the tank if the liquid level falls sufficiently. The float carries a pump 21 which withdraws the sludge collected in the central channel 23 through pipes 22 and discharges it through a pipe 24 on the arm 4 to a circular channel 25 at the periphery of the tank. The liquid is supplied to the tank up a central pipe 20, the upper end of which supports a brush 28 for the supply of current to the motors driving the carriage 7 and the pump 21. The arms 3, 4 are connected by a tie rod 6 and support a curved skimmer plate 26 which directs floating matter to a reservoir 27. The arm 3 may extend beyond the float and carry a short additional rake arm 14 and there may be a rake blade in the channel 23. In a modified form of apparatus the arm 4 is dispensed with and the travelling means comprise a driving unit and an idle unit carried by a framework forking from the scraper arm 3. The travelling-wheels may be rubbertyred and run on a flat track, guide wheels being provided to run against the vertical wall of the tank. In the apparatus shown in Fig. 8, the arm 3 is above the float and liquid level and the scrapers 5 are connected to the arms 3, 4 by chains 40. The liquid is supplied by a pipe 42 carried by a stationary bridge 43, the outer end of which is pivoted on a bearing 44 and has a counterweight 46, while the inner end is supported by a swivel bearing on the float. The rakes 5 have links forming a rake 49 in a central well 23. Specifications 304,735, [Group III], 365,630, 384,574, 417,473, and 433,775 are referred to.