INSULATED THREADED PIPE CONNECTION RESISTANT TO SEQUENTIAL PRESSURE LOADS Russian patent published in 2012 - IPC E21B17/42 

FIELD: machine building.

SUBSTANCE: insulated threaded pipe connection includes male element (1) with external thread (3) and female element (2) with internal thread (4) corresponding to external thread (3). One of the elements includes edge (5) passing behind thread (3) to free end of element (6). The other element includes cavity (10) for edge (5). Edge (5) includes the first zone (7) with peripheral surface facing the other element. In the first zone there located is the first insulating surface (13). The first insulating surface can be radially put with preload on the corresponding second insulating surface (11). The second insulating surface is located on peripheral surface of cavity (10) of the other element. Edge (5) has the second axially located zone (8) between the first zone (7) and free end of element (6). It includes the first radial supporting surface (14) facing the other element. The first radial supporting surface touches the second corresponding radial supporting surface (12). The second radial supporting surface is located on peripheral surface of cavity (10) of the other element. The first and the second zones (7, 8) are separated with the third zone (9) with radial stiffness that is lower than that of the first and the second zones (7, 8). The third zone (9) is capable of radial deformation towards the other element when pressure is applied to it. The third zone has minimum thickness in the range of 60% to 80% of edge thickness and axial length at the specified minimum thickness in the range of 0.25 to 5 mm.

EFFECT: resistance to sequential pressure loads is provided.