Rørkoplingsanordning og fremgangsmåte for å kople utvidbare rørseksjoner sammen

A first extensible pipe section (12) has a male part (16) with a conical shoulder (42) and a second extensible pipe section (14) has a matching female part (18) with a corresponding conical shoulder (46). One of these sections has a retaining element (40) to hold part of the other extensible pipe section. he shoulder is a face on one end of the pipe section and/or an element extending radially to define the shoulder, preferably the face of one section and a radially extending element on the other. The two conical shoulders define a space (60) between their surfaces when they are placed together before dilation of the connection. The space closes during dilation to bring the conical surfaces into contact with each other. The retaining element extends from one axial end along the outside of the second pipe section to the female part. The retaining element is in the form of a sleeve with a number of separate arms or fingers. The first and second pipe sections can be threaded, with a different angle between thread flanks of less than 10 degrees, most preferably at about 2 degrees. The male thread lead flanks are at 45 degrees, and the female thread lead flanks at 43 degrees to the main axis of the pipe. The male and female thread trailing flanks are at an acute angle, most preferably at about 83 degrees. Independent claims are included for; (1) A pipe connection using the above means of connection with a deformable element placed axially so it deforms whilst putting the first and second pipe sections in contact. This deformable element can be integral with the pipe section(s) or a separate component such as a stretchable or perforated ring or separate sections forming a ring; and (2) A coupling process for such a connection.