Device and process for perforating a duct fitted with a connector seat

A perforating device capable of perforating a process for perforating a fluid duct having a connector seat with a tapped barrel. The device generally includes a hollow cylindrical body, a cutting apparatus, a fluid passage and a valve. The cylindrical body has an internal volume, a longitudinal axis, a first open end, a second end opposite the first, and a threaded external surface. The cylindrical body can be threadingly received or retracted within the barrel such that the cylindrical body moves along the barrel toward or away from the fluid duct. The cutting apparatus is operably coupled to an end of the cylindrical body and is adapted to cut the duct by screwing the body into the barrel. The valve seals the internal volume of the cylindrical body in response to a differential pressure between the interior of the duct and the ambient atmosphere to prevent leakage from the duct.