| 摘要 |
PCT No. PCT/EP93/01544 Sec. 371 Date Dec. 9, 1994 Sec. 102(e) Date Dec. 9, 1994 PCT Filed Jun. 17, 1993 PCT Pub. No. WO94/00835 PCT Pub. Date Jan. 6, 1994Liquid impinges on two sides (15, 17) of a plate (11) of piezoelectric material, for the liquid to be exposed to ultrasonic waves by the plate (11) oscillating at ultrasonic frequency. An electric voltage is uniformly applied to the two sides (15, 17) of the plate (11) at its peripheral edge via annular contact plates (27). The contact plates (27) have resilient fingers (31) bent towards the plate (11) for transferring the voltage on the one hand and for uniformly clamping the plate (11) on the other. To prevent the liqui from short-circuiting the plate (11), a seal (21) is located at the periphery of the plate (11) and is compressed for tightness between the plate (11), and intermediate ring (25) and the contact plates (27). An upper and a lower annular disc (19, 23) serve for better sealing and clamping of the plate (11). |
