| 摘要 |
An electro-acoustic transducer is coupled to liquid in a conduit which terminates in a small orifice. Preferably, the acoustic impedance of the supply portion of the conduit is large compared with the acoustic impedance of the orifice. The liquid is under small or zero static pressure. Surface tension at the orifice prevents liquid flow when the transducer is not actuated. An electrical pulse with short rise time causes sudden volume change at the transducer, thereby creating an acoustic pressure pulse having sufficient amplitude to overcome the surface tension at the orifice and eject a small quantity of liquid therefrom. The expelled liquid is replaced by forward flow of liquid in the conduit under the influence of capillary forces in the orifice.
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