Casting gap control system

Claim 2

In an improved apparatus for flow casting metal strip of the type that includes, in combination: a crucible for holding molten metal; a movable chill body, providing a chill surface for deposition thereon of the molten metal for solidification; and a generally rectangular orifice, through which the molten metal may pass across a gap defined by the distance from the crucible to the chill surface, long sides of the orifice oriented generally perpendicular to the direction of motion of the chill surface, the improvement comprising: (a) means for setting a desired value for the gap; (b) gap measurement means, including a light source for providing a focused light beam at each of two short sides of the orifice, beam-shifting means for continually scanning the beam across the gap at the short sides of the orifice, and detection means associated with the beam shifting means for sensing time-varying intensities of the light beams after they have passed through the gap; (c) means associated with said detection means for comparing measured values of the time varying intensities of the light beams with desired values and for generating deviation signals in response to a comparison of the measured values with desired values that indicate any differences; and (d) means associated with said comparison means for translating the crucible perpendicular to the direction of travel of the chill surface in response to one deviation signal and for rotating the crucible, about an axis parallel to the direction of travel of the chill surface, in response to an other deviation signal, so as to minimize the differences.

Claim 3

The apparatus of claim 1 wherein the beam-shifting means comprises a rod having at least two parallel faces.

Claim 4

The apparatus of claim 1 wherein the beam-shifting means comprises a solid having at least three pairs of parallel faces.

Claim 5

The apparatus of claim 1 wherein the means for translating and rotating the crucible comprises: (a) a power source; (b) actuator means for adjusting the crucible position; and (c) relay means, activated by the deviation signals, for passing current from the power source to the actuator means.

Claim 6

The apparatus of claim 4 further comprising a motor control logic circuit interposed between the comparator means and the relay means.

Claim 7

The apparatus of claim 4 wherein the relay means is an on/off relay and an up/down relay, arranged in series, for passing the current from the power source to the actuator means.

Claim 8

The apparatus of claim 4 wherein the actuator means is a motor.

Claim 9

The apparatus of claim 1 wherein the light beams are provided by a single laser and a beam splitter positioned between the beam-shifting means and the gap.

Claim 10

The apparatus of claim 1 wherein the light beams are provided by two lasers, and the beam from each laser passes through a separate beam-shifting means.

Claim 11

In an improved method for flow casting metal strip onto the rapidly moving surface of a chill body of the type in which molten metal is passed from a crucible, through a generally rectangular orifice oriented with long sides generally perpendicular to the direction of motion of the chill surface, across a gap defined by the distance between the crucible and the chill surface, and onto the chill surface the improvement comprising: (a) setting a desired value for the gap; (b) provide a gap measurement means, including a light source for providing a focused light beam at each of the two short sides of the orifice, beam-shifting means for continually scanning the beam across the gap at the short sides of the orifice, and detection means associated with the beam shifting means for sensing time-varying intensities of the light beam after they have passed through the gap; (c) measuring the gap by providing the two focused light beams, continually scanning the gap with a light beam at each of the two shorter sides of the rectangular orifice, and measuring the time-varying intensity of the light beams after they have passed through the gap; (d) comparing measured values of the time-varying intensities of the light beams with the desired values and generating deviation signals in response to a comparison of the measured and the desired values that indicate any differences; and (e) translating the crucible perpendicular to the direction of the travel of the chill surface in response to one deviation signal and for rotating the crucible, about an axis parallel to the direction of travel of the chill surface, in response to an other deviation signal, so as to minimize the differences.

Claim 12

In an improved method for flow casting metal strip onto the rapidly moving surface of a chill body of the type in which molten metal is passed from a crucible, through a generally rectangular orifice oriented with long sides generally perpendicular to the direction of motion of the chill surface, across a gap defined by the distance between the crucible and the chill surface, and onto the chill surface the improvement comprising: (a) setting a desired value for the gap; (b) provide a gap measurement means, including a light source for providing a focused light beam at each of the two short sides of the orifice, beam-shifting means for continually scanning the beam across the gap at the short sides of the orifice, and detection means associated with the beam shifting means for sensing time-varying intensities of the light beam after they have passed through the gap; (c) measuring the gap by providing the two focused light beams, continually scanning the gap with a light beam at each of the two shorter sides of the rectangular orifice, and measuring the time-varying intensity of the light beams after they have passed through the gap; (d) comparing measured values of the time-varying intensities of the light beams with the desired values and generating deviation signals in response to a comparison of the measured and the desired values that indicate any differences; and (e) translating the crucible perpendicular to the direction of the travel of the chill surface in response to one deviation signal and for rotating the crucible, about an axis parallel to the direction of travel of the chill surface, in response to an other deviation signal, so as to minimize the differences.