| 摘要 |
A breakable coating was removed from a selected zone on the outside of a conduit by placing a number of spaced detonating cords against the surface of coating. The cords were exploded to produce sufficient cracks and fractures in the coating to allow its removal from the selected zone of the conduit. The explosive was PETN of RDX and the cords cont. 50-400 grains of explosive per-lineal foot of cord per-inch of spacing. Typically 35 rows of cord contain 400 grains of PETN per-lineal foot set on 1 inch centres.
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