| 摘要 |
An apparatus for cleaning calcites and other extraneous matter from the perforated casing of a sub-terrainian water well comprises a plurality of elongate explosive members 14 for lowering into the well, detonators 16 for detonating each member 14 to produce an explosion which propagates longitudinally of the well, and a plurality of short tubular attenuators 19 circumscribing the explosive members 14 at intervals along the length thereof. Each tubular attenuator 19 comprises a steel tube 20 and an annular ring 21 extending around the tube at a point along the length thereof. The tensile strength of the tube 20 is arranged to be less than that of the force produced by the explosion, whereas the tensile strength of the ring 21 is arranged to be greater than that of the force produced by the explosion. The rings 21 thus serve to attenuate the pressure wave substantially more than tubes 20, thereby helping to produce a more pronounced attenuation. Furthermore, the shape and direction of the pressure wave of the explosion can be altered according to the relative positioning of the ring 21 on the tubes 20.
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