GB1531835A - Control method and apparatus for the repeated pouring of identical quantities of molten material from a ladle with a bottom discharge orifice - Google Patents

Abstract

1531835 Automatic control of metal pouring BROWN BOVERI & CIE AG 10 Sept 1976 [10 Sept 1975] 37598/76 Heading G3N [Also in Division B3] A bottom discharge ladle has the rate of outflow into a mould controlled by the position of a plug 32 which is moved by a stepping motor 11 operated from a computer which processes signals of the weight of material in the ladle and the duration of the discharging operation. In order to obtain a uniform casting the rate of flow has to be controlled so that at the end of the casting time the mould is just full. Additionally the height of material in the ladle will affect the outflow rate so a strain gauge 5 monitors the weight of ladle 30. The computer responds to manually set values of duration and the like, and the output of strain gauge 5 to produce a number of pulses which operate stepping motor 11 to move plug 32 until a position monitor indicates to the computer that the required position is reached. An electromagnetic valve 16 is provided, which when de-energized, exhausts the air-pressure in chamber 38 and allows plug 32 to fall and stop the outflow of material. On restoration of power the stepping motor will be run to the closed position indicated by a limit switch ready for the next casting operation. The ladle shown is supported on strain gauge 5 and has a lid 33 which is supported from the plug bottom bearing 35 which also supports the top bearing 37 and the stepping motor 11 through frame 36. Hand wheels 47, 48 set the limits of travel of plug 32 and guide 40 prevents rotation of the plug. In operation the stepping motor drives gear 43 which rotates on screw 44 to raise or lower the plug. As the plug is raised the reservoir 38 is filled with air under pressure so that under failure conditions the air is exhausted and the plug drops to close orifice 31.