riser assembly, method for operation of a riser assembly, and any new feature or new combination.

摘要

an upright tube assembly comprising a main body enclosing a main passageway extending from a first end of the main body to a second end of the main body generally parallel to a longitudinal axis of the main body, the main body being suitable for mounting on a riser so that the main passage forms a part of a riser main passage, the riser assembly further including a seal assembly which is operable to provide a seal between the main body and a pipe that extends along the main passageway of the main body so as to substantially impede fluid flow along the main passageway around the pipe, and two or more bypass lines, each of which extends from a first hole in the main body to a second hole in the main body, the holes that extend through the main body for connecting the main passage with the exterior of the main body, the sealing assembly being located in the main body between the first and second holes, wherein a pump is located within each bypass line, the pump being operable to pump fluid along the bypass line where it is located.