Safety joint

2:

• The safety joint according to claim 1, further comprising at least one cylinder arrangement which is configured to compensate the safety joint and the at least one tension rod for internal pressure in the riser in the not activated mode and the partly activated mode and to compensate the safety joint for internal pressure in the riser in the fully activated mode.

3:

• The safety joint according to claim 2, wherein the cylinder arrangement is adapted to increase the forces acting against release of the first and second riser parts in the fully activated mode.

4:

• The safety joint according to claim 2, wherein the cylinder arrangement comprises one cylinder set which is configured to compensate the at least one tension rod for internal pressure in the riser in the not activated mode and the partly activated mode and to increase the forces acting against the release of the first and second riser parts in the fully activated mode.

5:

• The safety joint according to claim 2, wherein the cylinder arrangement comprises a first set of cylinders and a second set of cylinders, and wherein the first set of cylinders is adapted to compensate the at least one tension rod for the internal pressure in the riser in the not activated mode, the second set of cylinders is adapted to compensate the at least one tension rod for the internal pressure in the riser in the partly activated mode, and the second set of cylinders is adapted to increase the forces acting against the release of the first and second riser parts in the fully activated mode.

6:

• The safety joint according to claim 5, wherein the first set of cylinders is shorter in length than the second set of cylinders.

7:

• The safety joint according to claim 5, wherein the first set of cylinders is connected to the second set of cylinders through a mechanical link, and wherein pistons in the first and second sets of cylinders move equally in the not activated mode and the fully activated mode.

8:

• The safety joint according to claim 5, wherein the cylinder arrangement comprises a third set of cylinders which is adapted to be activated during the fully activated mode of the release unit.

9:

• The safety joint according to claim 8, wherein the third set of cylinders comprises a piston and is in communication with seawater on one side of the piston and with a fluid on the other side of the piston, and wherein the third set of cylinders is adapted to contribute to the force acting against release of the first and second riser parts in the fully activated mode.

10:

• The safety joint according to claim 5, further comprising a manifold which is adapted to distribute a fluid to the different cylinders in the cylinder arrangement in order to compensate for the internal pressure within the riser, the manifold comprising at least one flow regulating means which is adapted to regulate to which of the cylinders the fluid is distributed.

11:

• The safety joint according to claim 10, wherein the manifold comprises at least one bore which leads to a cylinder comprising a floating piston.

13:

• The method according to claim 12, further comprising, after the step of increasing the tension in the riser to a fully activated mode and thereby breaking the tension rods, activating a set of cylinders in a cylinder arrangement and creating a force in the safety joint acting against the release of the two riser parts, and allowing telescopic action in the safety joint.