Long life sparker for pulse powered underwater acoustic transducer

A long life underwater sparker has been developed by the US Navy as part of a pulse powered acoustic generator for minesweeping applications. This sparker has demonstrated continuous operation for more than one and a half hours at one kiloJoule discharge per pulse at a 10 Hertz rate. Additionally, the sparker was operated at one half kiloJoule discharges (10 Hertz) for more than two and a half hours. These operations were in a saltwater environment from a prototype high speed demonstration platform. This sparker design utilizes a coaxial configuration and is fabricated with off-the-shelf components and materials. In general, fabrication requires minimal facilities with the exception of the insulation between the anode (center rod) and the cathode (outer cylinder) which was fabricated by Amalga Composites Inc. With a proprietary process that utilizes cyclo-aliphatic compounds for the resin. The sparker is sacrificial which means the lifetime is dependent on the length of the sparker. The efficiency (electrical to acoustic), which depends on the specific configuration of the companion pulse power system, ranged from 6% for one kiloJoule discharge to 3% for one half kiloJoule discharges. The lifetime of the current design was dictated by the test requirements and could easily be extended. The sparker can be quickly changed out and the mounting component can be recycled. The advantages of this design are: simplicity of design, low fabrication cost (/spl sim/$70/sparker), seawater operation, relatively high efficiency and low hydrodynamic drag.