ULTRASONIC HORN WITH SIDELOBE SUPPRESSING CENTREPIECE

摘要

The assembly comprises a horn (12) with a bore (14) flaring from a throat (16) to a mouth (18). An ultrasonic transducer (60) is mounted in the throat and, when in position, abuts an internal annular shoulder (38) formed in an external ring (28) of a spider which supports a centrepiece (40). The centrepiece comprises a body which tapers forwardly and a reduced diameter stem at the rear formed in part by a rearward extension (46) of the body and in part by an inner ring (30) of the spider. The stem is surrounded by a rearwardly facing shoulder (52) and has a blind bore (54) opening rearwardly towards the transducer (60). The blind bore (54) has a flat bottom (56) which is nearer to the transducer (60) than the shoulder (52) surrounding the stem. This flat bottom and shoulder enhance the directionality of the beam transmitted or received by the assembly.