GB800384A - Improvements relating to agitating apparatus, particularly for dry-powder mixing - Google Patents

Abstract

800,384. Agitating apparatus. COLEMAN-WALLWORK CO., Ltd. Oct. 12, 1956 [Oct. 18, 1955], No. 29681/55. Class 86 [Also in Group XXIX] Apparatus for mixing dry powders, for example, the materials used for making shell moulds for casting purposes, comprises a casing 1 enclosing a pair of agitating elements 2 each composed of two castiron side plates 4 connected together by a plurality of stainless steel 1 rods 5 5 extending between the peripheries of the said plates and parallel to a shaft 3 so that they interengage as the elements of a Rootes blower. Rubbertipped scraping strips 6 which engage the inside of the casing 1 are carried on the extremities of the elements 2. An electric motor 8 drives the agitating elements at about 100 r.p.m. through reduction gearing contained within a housing 9 and through a coupling 10. Compressed air enters the apparatus at 37 and passes through traps 39, 40 to a junction piece 41 from which one pipe 42 leads to a vibrator control valve 22 and another pipe 43 leads to a two-way main control valve 44. A handle 45 is provided on the two-way valve 44 to control the supply of compressed air through the pipes 46, 47 to either side of a piston in a cylinder 33, the piston being connected to a plug 29 closing the outlet 28 of the mixer so that operation of the handle 45 controls the discharge of the mixed material into a conduit 36. Material enters the casing by an inlet pipe 13 from a hopper 14 the neck 19 of which houses a vibrator and has a stop-cock valve having a handle 20 which co-operates with a plunger 22a of a valve 22 to control the air supply to the vibrator so that the vibrator and stop-cock valve operate together. A pressure relief valve 23 is mounted on the side of the casing 1 and is connected to a junction piece 48, a regulating valve 50, a non-return valve 51 and a pipe 52 leading to an inlet pipe 15. On charging the apparatus the handle 20 is lowered and air displaced from the inside of the casing by the incoming material escapes through the pressure relief valve 23 and pipe 56 terminating in a filter 57. When the apparatus is charged the stopcock valve is closed and the vibrator stopped and the electric motor 8 is started. To discharge the mixed material the main control valve 44 is set to lower the plug 29 and compressed air is delivered through the regulating valve 50 to a connection 16 at the top of the mixer to blow out any material remaining in the casing. At the same time compressed air is delivered through a pipe 49 from the junction piece 48 to the pressure relief valve 23 forcing a piston inside it to seal off the interior of the casing from the atmosphere. More than one hopper may be used to charge the apparatus through inlets 15, 17 with various materials to be mixed. When they are not being used the inlets are closed by screwcaps 18.