Patent ID: 8875794

Claim:
In a riser extending between a floating installation and a subsea installation, the riser defining an internal riser passage and having at least two axially aligned riser segments, the improvement comprising a joint which includes: concentric inner and outer pipe segments which are moveable relative to each other in an axial direction and are each connectable to a respective one of the two riser segments, said inner pipe segment defining an inner passage which is continuous with the riser passage; an axially extending chamber which is formed between concentric portions of the inner and outer pipe segments, said chamber and said concentric portion of the outer pipe segment being isolated from the inner passage by said concentric portion of the inner pipe segment; a radially extending piston which is connected to one of the inner and outer pipe segments and divides the chamber into axially spaced-apart first and second chamber parts which are isolated from the inner passage; a fluid line connection extending between the first chamber part and the second chamber part; wherein at least said first chamber part in an initial position of the joint contains a mainly incompressible fluid which when the inner pipe segment is moved relatively out of the outer pipe segment is forced by the piston from the first chamber part through the fluid line connection and into the second chamber part; and a flow control device which controls the flow of said fluid from the first chamber part through the fluid line connection to the second chamber part to thereby control the relative movement of the inner and outer pipe segments.