US Patent 7573183 Flextensional vibration-free pressure oscillator

An apparatus for producing pressure oscillation of a fluid, incorporating hermetically sealed casing including a housing, a cover, a hermetic seal, a cylindrical flextensional transducer driven by piezoelectric or magnetostrictive driving member positioned in the inner cavity of the transducer and secured between two endplates, two springs providing for axial preloading and centering of the cylindrical flextensional transducer, two internal seals preventing fluid leakage between swept volume and other structure volumes; hermetic connectors for electrical connecting of the actuation member to energizing means, and fluid flow channel.