An ultrasonically excitable tool or probe is provided with a central bore, and a coupling for attachment to an ultrasonic transducer also provided with a central bore. Fluid may be injected along the communicating bores for filling a bowl or concavity on a distal end of the tool. Upon energization of the transducer, fluid in the concavity serves as a conventional ultrasonic cleaning bath for depending parts which the tool may be raised to accommodate in the concavity. This cleaning may be achieved in a confined space where the presence of the transducer is impossible or impermissible, which is further facilitated by the existence of an extended handle or shaft portion, containing the bore, on the ultrasonic tool. A particular shape of the concavity is found to have unexpected utility in creating and focussing an atomized spray.

A method to improve the high output characteristics of a ultrasonic transducer 1 by urging a cooling gas 13 to flow through the transducer, thereby passing a cooling member 18 between each adjacent pair of piezoelectric elements 6, 7. In a preferred embodiment sulfurhexafluoride (SF.sub.6) is used as cooling gas.

An electroacoustic converter is disclosed for converting electrical energy into mechanical vibrations at a predetermined frequency. The converter is supplied with alternating electrical power from a power supply. The converter has a metal front driver mass, a metal back driver mass, a front ceramic stack, a back ceramic stack, a spacer between said front and back ceramic stacks, and a fastener extending axially of the converter coupling the front and back drivers masses to clamp the ceramic stacks and the spacer between the front and back drivers. The front and back ceramic stacks are of a suitable piezoelectric ceramic material such that when energized with alternating electrical power from the power supply the piezoelectric material renders the converter resonant at the predetermined frequency. The spacer, back driver, and front driver masses are provided with fins to radiate heat from the converter. The converter exhibits substantially even temperatures and a vibrational node within the spacer.

A tranducer assembly for an ultrasonic surgical instrument includes a front driver having an elongate shaft in one direction and a stud extending in an opposite direction. An electromechanical transducer element is disposed around the stud. The transducer assembly also comprises a rear driver disposed around the stud on a side of the electromechanical transducer element opposite the front driver, the electromechanical transducer element being clamped between the front driver and the rear driver. An inertial or damping mass is fixedly connected to the stud at a point spaced from the rear driver. The stud is of length and thinness to act as a flexible vibration damping element.

A fluid delivery line is configured to provide slurry to a planarization process, e.g., of a planarization machine. Slurry within the delivery line is provided successive forward and reverse flows. Preferably, the flow reversals are performed on a supply side of a metering pump which is used for dispensing slurry from the delivery line to a planarization pad of the planarization machine. In another embodiment, a slurry distribution system comprises a pump configured to flow slurry from a slurry reservoir to a forward delivery line. A plurality of drop lines tap into the forward line along its length. A return line returns slurry from the forward line to the slurry reservoir. A variable volume cavity is coupled in fluid communication with the return line, and is operated with plus/minus volume displacements. Additionally, a passive or active mixer may be disposed in-line with the return line and at a location between the slurry reservoir and the variable volume cavity.