Abstract: A method for separating a liquid and in particular a liquid metal from heterogeneous constituents therein, comprises the steps of providing a passage for a flow of liquid containing heterogeneous constituents and directing ultrasound waves into the passage. The ultrasound waves are made to form standing waves in the liquid using a reflector and by tuning the frequency of the ultrasound waves. The standing waves cause extraneous particles in the liquid to coagulate at the nodes. The reflector is also designed to direct some of the ultrasound waves upwardly into the passage. The flow of the liquid metal through the passage and the ultrasound in the passage carry the coagulated particles into the slag on the surface of the liquid metal for removal. The ultrasound waves also cause cavitation effects which degas the liquid metal. An ultrasound particle detection device is also disclosed which includes a transmitting delay line, a receiving delay line and a reflector immersed in a liquid.

Abstract: A probe for ultrasound testing or treatment of a molten metal is provided. The probe includes an ultrasound transmitting rod having a downstream end adapted to contact molten metal under test or treatment. A piezoelectric crystal is provided on the probe and is adapted to supply ultrasound to or receive ultrasound from the rod. A rod cooling station is located near the downstream end of the rod and is operable to create in the rod, a steep temperature gradient at least equivalent to 700.degree. C. over a length of 50 mm from the point of melt contact for a cylindrical steel rod 25 mm in diameter when the probe is in contact with the molten metal at melt temperature. A method of testing a liquid molten melt is also provided.

Abstract: A probe for ultrasound testing or treatment of a molten metal comprises:an ultrasound-transmitting rod (10) of which one end is a "downstream" end (12) adapted to contact molten metal under test or treatment;a piezoelectric crystal (50) adapted to supply ultrasound to or receive ultrasound from the rod (10); androd-cooling means (16) located near to the downstream end (12) of the rod (10).A method for the treatment of a liquid metal melt, to reduce the number of inhomogeneous particles distributed through the melt comprises:creating a standing wave of ultrasound energy within the melt, e.g. using a probe as defined above, whereby the inhomogeneous particles concentrate, and are encouraged to coalesce, at the nodes of the standing wave; andseparating the coalesced particles from the bulk of the liquid melt.