Patent ID: 7459896
Filing Date: 2008-12-02
Classification: G01N

Abstract:
1. A method of measuring particles in molten metal with a Liquid Metal Cleanliness Analyzer (LiMCA), having electrically insulating wall means having a passage formed therein for passage of the molten metal, a first electrode inserted in the molten metal on one side of the wall means, a second and a third electrode connected to a current source and inserted into the molten metal on an opposite side of the wall means to the first electrode and equally spaced on either side of the first electrode such that the second and the third electrodes and the first electrode fall in a common plane; said method comprising: (a) feeding equal current directly from the current source to the second and the third electrodes, said current passing with the molten metal through the passage to the first electrode to create symmetrical current loops between each of the second and the third electrodes and the first electrode, which loops generate wanted pulse signals and are affected in an equal but opposite manner by electromagnetic noise; (b) adding the wanted pulse signals generated by each current loop to at least reduce the electromagnetic noise; and (c) subjecting the wanted pulse signals to analysis to measure particles in the molten metal based on said wanted pulse signals.