Patent ID: 8863848

Claim:
An apparatus for controlling the flow of downhole fluids, the apparatus comprising: a body having a throughbore and at least one port extending through a sidewall of the body to enable fluid communication between the throughbore and an exterior of the body; a flow control device for controlling the flow of fluids through the port and arranged to change configuration between a closed configuration in which fluid flow through the port is restricted and an open configuration in which fluid flow through the port is permitted; an actuator mechanism associated with the flow control device for selective actuation of the flow control device to change the configuration of the flow control device between the closed and open configurations; a locking device to lock the configuration of the flow control device; and an unlocking mechanism to unlock the locking device and to permit the actuator mechanism to change the configuration of the flow control device, wherein the unlocking mechanism is pressure operated and comprises a piston configured to move under pressure to remove, destroy or change the configuration of the locking device, and wherein the piston has a valved port to allow pressure equalisation between opposite axial sides of the piston.