Abstract: An apparatus for conducting ultrasonic waves to and from a body of a molten material. The apparatus includes a buffer rod for transmitting ultrasonic waves to the molten metal, a second buffer rod for receiving ultrasonic waves from the molten metal, piezoelectric elements associated with each buffer rod, and cooling mechanisms for protecting the piezoelectric elements by maintaining the buffer rods at a prescribed rate of thermal equilibrium with the molten metal. The cooling mechanisms are configured so as to facilitate regulation of the air flow about the apparatus.

Abstract: A method and apparatus for continuously monitoring the cooling capacity of a liquid coolant containing gas bubbles. The apparatus includes a measuring means for measuring the number density of the bubbles to infer the heat transfer characteristics of the liquid coolant, a control means for varying the amount of gas in the liquid coolant so that the number density is within a predetermined range and an electro-acoustic transducer in fluid contact with the liquid coolant capable of generating waves of sufficient intensity to cause cavitation in the liquid coolant in the area of the measuring means. In a preferred embodiment the electro-acoustic transducer is an ultrasonic horn.