Patent ID: 8746348

Claim:
An apparatus for releasing fluid from a riser assembly, the apparatus comprising: (a) a housing defining an interior space and an exterior region, the housing having first and second ends adapted for respective sealed connection in the riser assembly, the housing being defined on its interior space by a central cavity, the central cavity being adapted for passage of a drill string, the housing further comprising at least one first port and at least one second port; (b) a first gate in mating configuration with the housing, the first gate being moveable from (i) a sealed position that restricts fluid flow through the first port to (ii) an open position that facilitates fluid flow through the first port from the interior space to the exterior region of the housing; (c) a first actuator assembly connected to the first gate and configured for moving the first gate from the sealed position to the open position; (d) a second gate in mating configuration with the housing, the second gate being controlled independently of the first gate, the second gate being selectively moveable from (i) a sealed position that restricts fluid flow through the second port to (ii) an open position that facilitates fluid flow through the second port from the interior space to the exterior region of the housing; and (e) a second actuator assembly connected to the second gate and configured for moving the second gate from the sealed position to the open position.