GB896539A - Means for controlling the operation of material conveying devices - Google Patents

Abstract

896,539. Automatic feed weighers. KENNEDY VAN SAUN MFG. & ENG. CORPORATION. Aug. 5, 1959, No. 26721/59. Class 143. In an automatic feed weigher wherein the weighed batch of material is discharged from the weigh hopper 7 through a conveying pipe 19 by means of pressure fluid introduced via a valve 46 into the hopper 7 through inlets 45, and the material inlet 13 is controlled by a gate 20 and is pressure sealable by a closure member 33, the gate 20, member 33 and valve 46 each being operated by double acting fluid pressure rams 22, 37 and 48 respectively, the gate ram 22 is controlled by a first electromagnetic valve 31, 32 the magnet 32 of which is normally energized to hold the valve 31 in gate open position but is de-energized, through a load switch 60, on movement of the hopper 7 under a predetermined weight of material therein to move the valve 31 to gate closed position, and the closure member ram 37 and fluid inlet ram 48 are both controlled by a second electromagnetic valve 42, 43 the magnet 43 of which is normally de-energized to open the closure member 33 and close the inlets 45 but is energized, through a limit switch 73 on closure of the gate 20, to close the member 33 and open the inlets 45 for material discharge, Fig. 4, there being a third electrical control switch 64 which is operated by the build up of pressure within the hopper 7 to maintain the respective de-energized and energized conditions of the magnets 32 and 43 irrespective of return movement of the hopper, said switch 64 being returned to its initial position when the pressure in the hopper 7 falls, due to complete discharge of the material, and thereby resetting the valves 31, 32 and 42, 43 to hopper feeding positions. As shown the hopper 7 is resiliently mounted on springs 9 and carries an abutment 62 to operate the load switch 60. Closing of the switch 60 energizes a solenoid 68, Fig. 6, to close retaining circuit contacts 69 and also contacts 70 which complete a circuit to energize a solenoid 57. The energized solenoid 57 opens a switch 56 to de-energize to magnet 32 of valve 30 to permit closing of the feed gate 20 and the consequential closing of the limit switch 73. The magnet 43 of valve 42 is thereby energized via the contacts 70 Build up of pressure in the hopper 7 operates the switch 64 to cause opening of contacts 63 in the circuit of the solenoid 68 and simultaneous closing of contacts 77 which parallel the contacts 70. For discharging of partial loads, the discharge cycle may be initiated by a push button switch . 80 which parallels the load switch 60.