Apparatus and method for joining in a tube

An apparatus for joining a longitudinal seam in a tube, the apparatus comprising:

• a slit tube arranged to be deployed by progressively unwinding a coiled member into an extended form, wherein the member transitions from a flat form when coiled to a slit tube form when extended in which form the member is resiliently biased, the member having first and second longitudinal edges that overlap in the extended form in an edge region;
• a joining device positioned relative to the member to provide energy to the edge region of the member in its extended form to cause heating;
• a drive mechanism to provide relative movement of the joining device with the member such that the energy provided to the edge region progressively joins together the longitudinal edges of the slit tube as the member passes the joining device and thereby form a longitudinal seam in the tube;
• a detector downstream of the joining device for testing the join integrity in the seam;
• and
• a control system in communication with the detector and the drive mechanism, the control system being arranged to receive a signal from the detector indicating a portion of the tube an unsound join, and in response either:
• A) to transmit a control signal to the drive mechanism to back up the drive mechanism such that the portion of tube with the unsound join is passed again past the joining device and the join reformed, or
• B) provide a control signal to a second joining device located after the detector to cause the second joining device to reform the join of the portion of tube with the unsound join.

An apparatus for joining a longitudinal seam in a tube, the apparatus comprising:

• a slit tube arranged to be deployed by progressively unwinding a coiled member into an extended form, wherein the member transitions from a flat form when coiled to a slit tube form when extended in which form the member is resiliently biased, the member having first and second longitudinal edges that overlap in the extended form in an edge region;
• a spool for holding the coiled member such that an end of the member in the extended form can be fed into a borehole;
• a device for towing the extended member into the borehole until the member has reached a desired position;
• a joining device positioned relative to the member to provide energy to the edge region of the member in its extended form to cause heating, wherein the joining device comprises a pig arranged to move through the borehole down the inside of the extended member such that the energy provided to the edge region progressively joins together the longitudinal edges of the slit tube as the pig passes along the inside of the tube and thereby form a longitudinal seam in the tube.