| 摘要 |
PCT No. PCT/GB95/01025 Sec. 371 Date Oct. 28, 1996 Sec. 102(e) Date Oct. 28, 1996 PCT Filed May 5, 1995 PCT Pub. No. WO95/30496 PCT Pub. Date Nov. 16, 1995A segmented ring transducer comprising a plurality of arcuate ring sections (21) coupled together, each section (21) comprising a plurality of rectangular piezoelectric ceramic blocks (22) arranged into a stack (27, 28) with one or more tapered wedges (23) spaced in the stack, the piezoelectric stack (27, 28) being assembled between opposed end couplings (24, 25), pre-stress bolts (26) connecting together the opposed end couplings (24, 25) in each ring section (21) to hold together each ring section assembly (21). The arcuate ring sections (21) can be identical. Adjacent ring sections (21) can be connected together by further bolts. Alternatively, the ring transducer can be formed as a split ring with an arcuate portion (20) of the ring missing, the arcuate portion being formed by omitting either one or more arcuate ring sections (21) or an arcuate portion (20) of the ring which is not equivalent to an integral number of arcuate ring sections (21). The segmented ring transducer can be constructed so that each arcuate portion (20) of the ring is identical and the wedges (23) are spaced in each arcuate ring section (21) such that in the assembled ring the ceramic blocks (22) form a regular polygon. |
