Plasma furnace

摘要

A plasma furnace comprises a furnace body (1) allowing molten slag (6) to stay therein; a plasma torch (2) mounted on said furnace body (1) for striking a plasma arc (3) against said molten slag (6) while injecting plasma gas; an inlet (12) provided in said furnace body (1) for supplying said furnace body (1) with waste (4) therethrough; an outlet (7) provided in said furnace body (1) for allowing a portion of said molten slag (6) to leave said furnace body (1) therethrough; a flue (11) for carrying up waste gas therethrough when said waste gas has been discharged through said outlet (7) together with said portion of said molten slag (6); a pressure sensor (604) for detecting a variation in furnace pressure or a variation in plasma gas supply pressure; integrating means (606) for separating specific frequency bands from a waveform of an output signal taken from said pressure sensor (604) and subjecting said specific frequency bands to spectral integral; and comparator means (607) for receiving values obtained from said spectral integral in said integrating means, comparing said values with a prescribed reference value, and generating an abnormality indicating signal when said values are greater than said prescribed reference value.