Abstract: A crucible used in a powder pack plating process has an aperture below the upper surface of the powder pack to allow a density driven flow of the plating gas generated by the powder pack to move through the powder pack.

Abstract: A group of nozzles are submerged in a tank of liquid to produce convergent-divergent vortices and cavitation in a liquid which in turn produce acoustic vibrations which assist in cleaning articles placed in the liquid, or in emulsifying a mixture of liquids. Each such nozzle comprises a body, with a central axis, an inlet at one end for supply of liquid under pressure thereto, and a plurality of discrete outlet ports at the other end transversely spaced from the central axis, the axes of the ports converging externally of the body towards the central axis whereby liquid supplied to the inlet under pressure emerges from the outlets in discrete jets directed to pass close to but not to intersect the central axis of the body.