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(11) | EP 0 184 377 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Borehole devices disarmed by fluid pressure |
(57) An apparatus (10) for actuating an explosive device downhole in a borehole includes
a mechanism for actuating the explosive device in response to a stimulus, and means
for disarming the actuating means in response to the application of fluid pressure
thereto. The actuating means can be actuated by a pressure differential across a piston
(122) causing movement thereof and of rod (120) to release firing pin (86). In such
case, the disarming means includes a valved port (232) operable by sliding movement
of sleeve 64 to equalize pressure across piston (122). Sleeve 64 is moveable in response
to certain pressure conditions. |