Patent ID: 6603296
Filing Date: 2003-08-05
Classification: G01N

Abstract:
In a probe for insertion into molten metal to detect and measure particulates suspended therein using the electric sensing zone method, the probe comprising:a sealed inner tube of an electrically insulative material forming a molten metal receiving chamber, the tube including at least one orifice proximate an insertion end of the probe to permit molten metal to flow into the chamber; a first electrode extending into the chamber for engaging metal within the chamber; a second electrode surrounding at least a portion of the inner tube for engaging molten metal outside of the chamber, the first and second electrodes being connectable to a measurement device for establishing a current path through the electrodes and passing through the at least one orifice and for measuring changes in the electrical potential between the electrodes produced by the passage of particulates entrained in the molten metal passing through the orifice; an outer sheath of heat resistant material surrounding at least a portion of the second electrode to provide thermal insulation therefor; a gas passageway extending out of the inner tube for connection to a vacuum source to create a pressure differential between the inside and outside of the inner tube for facilitating the flow of molten metal through the orifice, wherein the improvement comprises a liquidus depressing material within the chamber for alloying with molten metal entering the chamber to lower the liquidus temperature of the molten metal in the chamber and permit a longer time period for detecting and measuring particulates in the molten metal.