GB1162802A - Transducer - Google Patents

Abstract

1,162,802. Transducers; reflectors. WESTINGHOUSE ELECTRIC CORP. 28 Aug., 1966 [13 Sept., 1965], No. 51707/68. Divided out of 1,162,801. Headings H4J and H4X. A transducer comprises two conical surfaces 37, 39 (Fig. 1) facing one another and on the same central axis, and at least one oscillatory driving element 44 having front and rear surfaces 45, 46. The surfaces 45, 46 provide acoustic signals F and R respectively, upon excitation by a fixed frequency signal which propagates an. acoustic wave of wavelength X. The signal R strikes the surfaces 37 and 39 in sequence and, after a distance of travel of n#/2, where n is an odd integer, emerges beyond the element 44 and displaced therefrom, and is propagated past the front surface thereof. The signal R, after travelling the distance n#/2, may lie in a phase front with the signal F or may lead or lag. In another embodiment, cylindrical driving elements 50, 50<SP>1</SP> (Fig. 3) are excited in the hoop mode. Conical members 59, 62, 62<SP>1</SP>, 59<SP>1</SP> have the same central axis and are aligned apex to apex. The components 50<SP>1</SP>, 59<SP>1</SP>, 621 may be of a different size and operate at a different frequency from components 50, 59, 62. For a broad band transducer, several elements 50, 50<SP>1</SP> ... 52<SP>1</SP> may operate at different frequencies. A rubber cover (78), Fig. 2 (not shown), is provided, the internal cavity being filled with fluid through an aperture (80) closed by a plug (81). A unit having six surfaces of revolution (Fig. 4) has at the right-most end a convex surface of revolution to provide a curved reflected wave. The other five surfaces are cylindrical but the valley at the left-hand end is such that the left reflected wave leads the other wave fronts.