GB1262069A - Crust breakers for electrolysis cells - Google Patents

Abstract

1,262,069. Crust breakers; charging electrolytic furnaces. SWISS ALUMINIUM Ltd. 23 Oct., 1970 [24 Oct., 1969], No. 50525/70. Heading F4B. A crust breaker for an electrolytic furnace producing aluminium comprises one of a pair of trolley carriages 57 mounted on a semi-portal crane 10 and having an impact beam 92 hinged thereto, a tool assembly 74 with impact tool 75 mounted in a bracket 84 hinged to the beam 92, a pneumatic motor 77 incorporating a stroke adjustment device 76 mounted on the carriage 57 and adapted to swing the beam and thus drive the impact tool 75, and a pneumatic control device 86 coupled to the bracket 84 which determines and controls the force necessary to swing the tool assembly 74 about the axle 85, Fig. 8, in a direction perpendicular to the longitudinal axis of the furnace. The control device 86 comprises a pneumatic motor 87 subject to pressure at 90 from a solenoid air valve 94, locking the tool 75 by a limit stop 102 on the bracket 84. Only if a lateral force on the tool exceeds the pressure in the space 90 will the tool be deflected. In the above position space 91 is connected to atmosphere through space 101 in said valve 94. When the tool 75 strikes the crust a signal energizes the solenoid 96 moving piston 97 across and allowing access of air to space 91 in motor 87. This reduces considerably the latera force necessary to move the tool 75 laterally preventing damage thereto during the picking operation. A torsion device 139 (detailed in Figs. 10 and 11) allows the tool 75 to deflect in the longitudinal direction of the furnace. Charging.-On the crane bridge 38 is an alumina hopper 42 with aerating bottom plates 46 whereby the alumina is fluidized before feeding through a delivery device 49 associated with each carriage 57. The delivery device 49 comprises a slide valve 50 opening into a rotary pocketed valve 51 (Fig. 6) and compressed air operated obturators 53 serving discharge pipes 54 on either side of the impact tool 75. Also on either side of the tool 75 are scraping devices 113 described in Specification 1,262,068 for distributing the alumina over the bath. Driving gear.-Longitudinal movement of the crane is by carriages 12 on rails 11 driven by motors 14 through gearing 15 and wheels 16. The opposite side of the crane bridge 38 is supported by an undriven carriage 13 including a parallelogram frame 29, 30, 33 incorporating springs 31, 32. Transverse movements of the trolley carriages 57 are by motors 59 actuating wheels 58 on rails 56, lower stabilizing rollers 61 engaging rails 64 and being provided with rocking levers 62 and tension springs 63. A travel programme transmitter (66, Fig. 1) and a furnace programme transmitter (68, Fig. 1) are among the devices ensuring automatic control and sequential operation of the charging crust breaker.