Automatic adjustment of burner height above workpiece - esp. on flame cutting machines, by monitoring the conductivity of gas burner flame

摘要

A resistor and capacitor are connected in parallel with the flame, which is connected via a buffer resistance to a source providing a measuring voltage. The workpiece is connected via an adjustable voltage divider to source; whereas a measuring amplifier is connected between the workpiece and the source. The output of the amplifier is fed to an unstable Schmidt trigger connected to relays employed to raise or lower the burner. The Schmidt trigger may be replaced by an electronic circuit actuating a motor which adjusts the height of the burner. Used esp. on portal flame cutting machines, where the portal carries several burners, all of which can be automatically adjusted.