GB940506A - Method and apparatus for the pneumatic conveyance and packaging of dry divided solidmaterials - Google Patents

Abstract

940,506. Pneumatic conveyers; packaging machines. ST. REGIS PAPER CO. April 19, 1960 [May 1, 1959], No. 13704/60. Headings B8A and B8C. [Also in Division G1] The air supply to a fluidizing container 41, Fig. 2, for discharging bulk material into bag filling nozzle 16 is controlled during the filling operation to maintain the energy level of the material below a condition of turbulence and instability. Fluidizing air is supplied through valves 61, 64 which direct the flow through alternative preset adjustable flow passages 57, 59 to change the flow between two predetermined values during the charging and discharging periods of the operating cycle. The valve 61 controls the flow to the primary supply line 43 for fluidizing screen 44 at the base of the container 45 and the valve 64 controls the flow to a secondary air line 52 for a perforated tube inlet 51 arranged above the screen 44. The flow passages 57, 59 are adjustable according to the material used and in one example during charging of the container 41 from the supply hopper 49 through feeder 50 the passages 57 are set to large openings so that the hopper 41 may be brought up to full operating pressure in a minimum of time. During filling of a bag when the outlet valve 19 is opened, the valves 61, 64 automatically change to direct the flow through passages 59 which are set to restrict the flow to the minimum necessary for satisfactory fluidizing of the material. An automatic control system (Fig. 4, not shown) for the various valves including also a hopper vent valve 70 is arranged to move the valves to the required different positions during the operating cycle, which is started by push button and stopped by either push button or automatically by the bag weighing apparatus. The control system may automatically open and close the vent valve 70 just prior to a bag filling operation to obtain an explosive material loosening effect within the container. The vent valve 70 may further be opened before complete discharge in order to reduce the flow of material to a slow trickle for more accurate weighing purposes. Examples of the application of the apparatus to an open top container and to a closed top container having an automatically opened and closed valve for gravity charging are described. Packaging-machines.-The scale pan 96, Fig. 3, supporting the bag (not shown) is tilted by an hydraulic ram 101 which is sequentially operated during the filling cycle. During filling of a bag the pan 96 is jerked suddenly downwards to shake the bag and assist in its complete unfolding. This operation is performed before the bag is so heavy that a sudden dropping of material due to unfolding would otherwise cause premature movement of the weighing mechanism to a full load portion at which the delivery valve 17 automatically cut off. After filling and release of the bag clamp 20 the pan 96 is tilted slowly upwards to facilitate removal of the bag.