Patent GB-326456-A (GB)
Title: Improvements in feeding devices for powdery or granular materials
IPC: B65B1/18
Filed: 1928-12-11
Abstract: 326,456. Marks, Sir G. C., (Bates Valve Bag Corporation). Dec. 11, 1928. Filling powdered material into valve bags.-A feeding device for powdery or granular material and more particularly for feeding such material into valve bags comprises a rotary propeller 35, Fig. 1, having radial blades, a casing 33 surrounding the periphery of the propeller and having a discharge opening 38 and means such as a screw 29 - - 32 to press the material axially into the space between the propeller blades 35. A hopper 12 feeds the material down a shoot 11 into a casing 10, a stirrer 28 on a, vertical spindle 12 agitating the material before it enters the propeller 29 - - 32. The spindle 13 is driven through bevel wheels 15, 17 which are pressed into engagement by a spring 26, the pressure of which is adjusted by a nut 23. The material is forced by the screw 29 - - 32 into the radial blades of the independently driven propeller 35 from which it is fed laterally into the nozzles 41 to valve bags. The flow through the nozzles 41 is regulated by slide valves 39. When the material packs, &c., the screw 29- - 32 lifts the spindle 13 and disengages the bevel wheels 15, 17 until the accumulation has been disposed of, whereupon the spring 26 presses the bevels into engagement and the feeding proceeds. In a modification, Fig. 3, (not shown), the spindle 13 is weighted and is adapted to slide through a worm wheel driven by a worm on a motor shaft. A flange on the spindle contacts with a spring plunger, which, in the normal position closes an electric contact to complete the electrical circuit of the motor. When the spindle 13 is raised, the circuit is broken and the motor stopped. In Fig. 4, the screw 28<b>, which is immovable longitudinally, is driven by a belt 37b mounted on a cone 35<b>, along which it is moved by a fork 38<b> connected by a nut to a screwed spindle 39<b> driven through a worm and worm-wheel by the motor 42<b>. The outer surface of the belt 37<b> drives frictionally a cone 34b geared by bevelwheels 30<b>, 29<b> to the feed-screw spindle. A diaphragm 44b beneath the screw 28<b> is normally pressed upwards by a spring 45<b> and is provided with a spindle 46b which moves an electrical contact 48b between two fixed contacts 51b, 52b, according to the pressure of the material on the diaphragm. When the spring 45b raises the diaphragm, contacts 48b and 51<b> are made and the motor 42b energized to move the belt 37b into the position shown whereby the screw 28<b> is driven at maximum speed. An automatic stop switch is operated when the fork 38<b> reaches the limit of its travel in either direction. When the material packs and forces the diaphragm 44<b> down, the contacts 48<b> and 52<b> are made and the motor driven in the opposite direction so as to move the fork towards the small end of the pulley. If the resulting slowing up of the screw does not relieve the pressure, the pulley moves the belt off the cone on to the cylindrical part 36<b> to stop the drive. Normally the screw 28<b> will be driven at such speed as to maintain contact 48<b> between contacts 51<b> and 52<b> whereby a constant pressure is maintained on the material fed to the propellers 17<b> and 18<b>, whether both or only one of the propellers is discharging or whether the discharge is continuous or intermittent. The propellers 17<b> and 18<b> are mounted on a horizontal shaft 19<b> driven by a. pulley 20<b>. Discharge openings 21<b> and 22<b> lead to the filling nozzles. A single radial discharge propeller, Fig. 5, (not shown), may be used, in which case it is mounted on an extension of the spindle 46<b> which is slidable on the driving pulley of the propeller. The feeding device is adapted to be used with apparatus which weighs the receptacles while they are being filled and shuts off the discharge through openings 21b, 22<b> respectively when the receiving receptacle has reached the desired weight. The weighing apparatus is set to close the discharge apertures slightly before the desired weight is reachd.