Patent ID: 7252178

Claim:
An acoustic fluid machine comprising: an acoustic resonator; a valve device comprising a suction chamber for sucking fluid from outside and a discharge chamber for discharging the fluid from the acoustic resonator at a first end of the acoustic resonator; and an actuator comprising a piston at a second end of the acoustic resonator, said piston being reciprocated to generate resonance in the acoustic resonator to greatly increase pressure of the fluid, an inner surface of the acoustic resonator being formed by a curve in which variation rate of a cross-sectional area is zero at the first and second ends of the acoustic resonator, said curve gradually increasing and decreasing at substantially the same gradients between the first and second ends, and the curve of the inner surface complying with the formula of a half cosine function of the form: r ⁡ ( x ) = r p - r o 2 ⁢ cos ⁡ ( π L ⁢ x ) + r p + r o 2 where L is the length of the acoustic resonator; r p is the radius of the second end of the acoustic resonator; and r o is the radius of the first end of the acoustic resonator.