Patent ID: 8715567

Claim:
A molten metal flow controller for controlling the release of molten metal from a tap hole in a metal melt furnace, the molten metal having a flow rate through the tap hole, the flow controller comprising: a first plunger controllably movable into and out of the tap hole, the first plunger shaped and sized to close at least in part the tap hole when the first plunger is positioned in the flow of molten metal from the tap hole between a first position and a second position in proximity to the tap hole, the first position being nearer to the tap hole than the second position, the first plunger reducing the flow rate of molten metal from the tap hole as the first plunger moves from the second position toward the first position, the first plunger allowing an increase in the flow rate of molten metal from the tap hole as the first plunger moves from the first position toward the second position; a first actuator operatively associated with the first plunger, the first actuator controllably moving the first plunger in a discrete manner between the first and second positions; and a second plunger removably insertable into the tap hole to fully close the tap hole; a second actuator operatively associated with the second plunger, the second actuator being operable to move the second plunger between a closed position at which the second plunger fully blocks the flow of the molten metal through the tap hole, and an open position at which the second plunger is withdrawn from the tap hole to allow the molten metal to flow through the tap hole; a sensor operatively associated with the first actuator, the sensor measuring the flow rate of the molten metal from the tap hole, generating a signal representative of the measured flow rate, and communicating said signal to the first actuator; wherein when the flow rate from the tap hole is less than a first predetermined value the first actuator moves the first plunger away from the first position and toward the second position in response to the sensor signal until the sensor signal communicates to the first actuator that the measured flow rate equals the first predetermined value, and wherein when the flow rate from the tap hole is greater than a second predetermined value the first actuator moves the first plunger away from the second position and toward the first position in response to the sensor signal until the sensor signal communicates to the first actuator that the measured flow rate equals the second predetermined value.