Emergency release device for drilling

A control system for emergency use in onshore and offshore well drilling operations operable to sever anchor chains, mooring cables, drill pipes and other tethering devices where the severing apparatus of the system is initiated and operated independently of local electrical power sources, comprising:

• a metal cutting means;
• first circuit means containing a first pressurized medium;
• pressurized medium means for actuating the cutting means;
• at least one pressure vessel in communication with said first circuit means and with said pressurized medium means;
• means for maintaining said pressurized medium in said pressure vessel at a pressure level sufficient to actuate said pressurized medium means for further actuating at least one cutting means;
• valve means in communication with said first circuit means, with said pressure vessel and with said pressurized medium means for applying medium pressure to said cutting means;
• trigger means for operating said valve means in rapid fashion whereby said cutting means is actuated;
• and
• wherein said means for maintaining said first pressurized medium in said pressure vessel at a sufficient pressure level comprises at least one pneumatic pump, and wherein said trigger means is a pneumatic trigger means, said system further comprising an air accumulator for supplying pressurized air to said at least one pneumatic pump and to said pneumatic trigger means.

A control system for emergency use in onshore and offshore well drilling operations operable to sever anchor chains, mooring cables and drill pipes comprising:

• a first circuit containing a first pressurized medium;
• cutting means connected operatively to said first circuit responsive to said pressurized medium;
• a second circuit containing a second pressurized medium;
• valve means operatively connected to said first circuit responsive to said second pressurized medium, wherein said valve means comprises a plurality of four-way valves, each having a first position wherein said first pressurized medium is poised for delivery to said cutting means, a second position wherein said first pressurized medium is conveyed to said cutting means and a third position wherein said first pressurized medium is redirected to a medium reservoir;
• and wherein said valve actuating means indexes said four-way valves between said first, second and third positions;
• and
• pressurized medium valve actuating means in said second circuit responsive to said second pressurized medium for operating said valve means whereby said first pressurized medium is directed to said cutting means for emergency operation of said cutting means.