US Patent 7530397 Explosive pipe severing tool

A pipe severing tool is arranged to align a plurality of high explosive pellets along a unitizing support structure whereby all explosive pellets are inserted within or extracted from a tubular housing as a singular unit. Electrically initiated exploding wire detonators (EBW) are positioned at opposite ends of the tubular housing for simultaneous detonation by a capacitive firing device. The housing assembly includes a detachable bottom nose that permits the tool to be armed and disarmed without disconnecting the detonation circuitry. Because the tool is not sensitive to stray electrical fields, it may be transported, loaded and unloaded with the EBW detonators in place and connected.