A detonating delay relay for shock or signal tube application so made as to be bidirectional. Comprising a delay detonator having a plug which holds two lengths of shock tube sealed at the ends. The detonation pulse is transmitted from one length of shock tube to the delay detonator. After a suitable delay, initiation of the other length of shock tube takes place.
A method and apparatus adapted to provide a time delay between the hydraulic actuation of the firing head assembly by fluid pressure and the detonation of a downhole explosive device used in subterranean wells, such as a perforating gun. In a preferred embodiment, the firing head assembly can be quickly and easily connected in a tubing string intermediate the ported sub and the perforating gun or other explosive device. In one preferred embodiment, the hydraulically-actuated firing head assembly is provided with five combustible columns which are generally coextensive. When the fluid pressure applied to the firing head assembly is sufficient to actuate the firing head assembly, the actuation mechanism, such as a firing piston, initiates a combustive reaction in one end of the first combustible column. When the combustive reaction reaches the other end of the first combustible column, it is communicated to one end of the second combustible column. The second combustible column likewise combusts and communicates the combustive reaction to one end of the third combustible column. This cycle continues through the third, fourth and fifth combustible columns. When the combustive reaction reaches the end of the fifth combustible column, the combustive reaction is communicated to and detonates the perforating gun or other downhole explosive device.
A transmission tube initiator comprises a body having a passageway formed therein for receiving and retaining an initiator charge. A holder holds a side of a transmission tube in close proximity to the charge. The charge provides an initiation signal which penetrates the transmission tube and initiates a reactive substance contained in the transmission tube.
A signal tube operated switch includes a contact arrangement which is moved from a first, open circuit position to a second, closed circuit position by a shock wave or pressure pulse initiated by a detonator. The switch is preferably an electric switch and in at least one embodiment includes a movable conductive piston consisting of at least one portion in continuous conductive engagement with the conductive signal tube. The other portion of the contact arrangement causes a change in the circuit after the contact arrangement is relocated to the second circuit closing position. Accordingly, the overall working efficiency of delay detonators is improved.
Signal transmission devices contain within a housing (12) at least a pair of signal transmission lines, e.g., signal transmission tubes (16, 18) having respective tube ends (16a, 18a) disposed within the housing to provide at least one input tube and at least one output tube. Delay train means (22) are interposed between at least one of the tubes and a detonator charge (20) contained at the closed or active end (12a) of the housing. Alternatively, both the input and output tubes may have a delay train (22', 22'') interposed between it and the detonator charge. In another embodiment, a signal transfer charge (28) may connect the input and output tubes (16'', 18'') in signal transfer relation to each other. In operation, selected delays may be attained between initiation of the detonator charge and one or both of ignition of the delay train means and generation of an output relay signal in the output tube. A plurality of relay and initiator devices (34) may be connected in sequence by signal transfer connectors (46) connecting tubes (42, 40) in signal transfer relationship.
A detonator (10) is equipped with an input lead (29) having multiple signal transmission lines (30, 31) which provide redundant initiation signals to the target charge (14) of a detonator (10, 10') thereby increasing the reliability of initiation. The multiple signal transmission lines (30, 31) may be made of shock tube and can be part of a long or short input lead (29, 129) and may be initiated by any suitable means, for example by being disposed in signal transmission relation to a detonating cord (60, 62) to improve the reliability with which a signal is transferred from the detonating cord (60, 62) to the detonator (10, 10').
