Telescopic riser joint

Abstract

The invention relates to a telescopic riser joint for connecting a first riser part and a second riser part, the riser joint comprising: a first pipe part ( 8 ) and a second pipe part ( 9 ) comprising means for connection to the first riser part and the second riser part respectively, which first and second pipe parts in use are arranged to form part of a riser with an internal flow passage, a cylinder arrangement comprising a first set of cylinders ( 32 ), each cylinder having a piston rod with a piston head ( 51 ) and a cylinder housing, the piston rod and cylinder housing being respectively connectable to one of the first pipe part or second pipe part, wherein one side of the piston head in use is in communication with external pressure providing an axial force acting in the longitudinal direction of the riser, and the other side of the piston head is facing a sealed chamber ( 52 ), where the cylinder arrangement is configured such that a fluid in the sealed chamber and a fluid on the other side of the piston head give a resultant force tensioning the first riser part and the second riser part.

1 . A telescopic riser joint comprising:
 a first pipe part and a second pipe part which each comprise means for connection to respective first and second riser parts, the first and second pipe parts being overlapping and in use arranged to form part of a riser with an internal flow passage;   a cylinder arrangement comprising a first set of cylinders, each cylinder having a piston rod with a piston head positioned within a cylinder housing, the piston rod and cylinder housing being respectively connected to one of the first pipe part or the second pipe part;   wherein one side of the piston head in use is in communication with external pressure which provides an axial force acting in a longitudinal direction of the riser and the other side of the piston head faces a sealed chamber; and   wherein the first set of cylinders is configured such that a fluid in the sealed chamber and the external pressure produce a resultant force which tensions the first riser part and the second riser part.   
     
     
         2 . The telescopic riser joint according to  claim 1 , further comprising a second set of cylinders, which each comprise a piston rod with a piston head positioned within a cylinder housing, the piston rod and the cylinder housing being respectively connected to the first pipe part and the second pipe part, and wherein one side of the piston head is in fluid communication with internal fluid in the riser and compensates the telescopic riser joint for internal pressures in the riser. 
     
     
         3 . The telescopic riser joint according to  claim 1 , wherein the riser joint comprises an override system adapted for increasing the connection force between the first riser part and the second riser part. 
     
     
         4 . The telescopic riser joint according to  claim 2 , wherein the first set of cylinders and the second set of cylinders are arranged next to each other around the periphery of the riser. 
     
     
         5 . The telescopic riser joint according to  claim 1 , further comprising a manifold which is adapted to distribute the internal pressure within the riser to the different cylinders in the cylinder arrangement, the manifold having at least one bore leading to one cylinder comprising a floating piston and a stop surface for the floating piston. 
     
     
         6 . The telescopic riser joint according to  claim 1 , wherein the riser joint is arranged in a lower half of the riser. 
     
     
         7 . The telescopic riser joint according to  claim 2 , wherein the number of cylinders in the first set of cylinders and in the second set of cylinders are adjustable.