Internal tree cap and itc running tool

Abstract

Internal tree cap (ITC) adapted to be installed in the bore of a subsea well unit or to an internal tubular element of the same, comprising a locking element for releasably locking the internal tree cap to said subsea well unit or internal tubular element. The ITC further comprises a fluid channel extending through a fluid barrier between the lower and upper part of the internal tree cap, which fluid channel is blocked by a burst element adapted to break and open for fluid flow through the fluid channel when exposed to a predetermined pressure difference over the burst element. The invention also relates to an ITC running tool and a locking mechanism for supporting the ITC in the tool.

1 - 16 . (canceled) 
     
     
         17 . A locking Locking mechanism for locking to internal or external locking grooves of a circular bore or member, the locking mechanism comprising:
 respectively, characterized in that it comprises
 a main body comprising with a plurality of locking members arranged along an inner or outer perimeter of the main body, the locking members being rotatable supported on the main body about respective rotation axes; 
 an actuation ring arranged within the inner perimeter of the main body or outside the its outer perimeter, respectively, said actuation ring comprising a plurality of engagement elements which extend extending into engagement slots of the locking members, or vice versa, so as to rotate the locking members about said axes by rotation of the actuation ring with respect to the main body; and 
 wherein the locking members, according to their rotational position, are adapted to assume a locking position; 
 wherein their perimeter extends a first distance radially out from the locking mechanism or radially inwardly from the locking mechanism; and 
 wherein the locking members are adapted to assume an unlocked position; and 
 wherein said distance is shorter than the first distance or non-existent as the distance from the rotation axes of the locking members to their perimeter varies along the perimeter.