| 摘要 |
A method and apparatus for detecting and measuring suspended solid particles in a molten metal, even if the metal also contains liquid and/or gaseous inclusions. The method involves moving molten metal through an orifice of predetermined hydrodynamic diameter provided in an electrically non-conductive barrier. As the molten metal is moved through the orifice, a current path is established by passing a current through the orifice from electrodes positioned on opposite sides of the barrier. Changes in voltage of the current are measured as the metal is drawn through the orifice, and the number of particles suspended in said metal drawn through the orifice is detected from the voltage changes. The metal, immediately before being moved through the orifice, is conveyed through a passage defined by an electrically non-conductive surface positioned in the current path, the passage including a region having a hydrodynamic diameter of between 2 and 10 times the hydrodynamic diameter of the orifice, at least a part of the region being of substantially constant hydrodynamic diameter. The provision of the passage upstream of the orifice has the effect of removing substantially all liquid and gaseous inclusions from the molten metal before the metal passes through the orifice.
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