Methods and apparatus for repairing a tubular structure

An apparatus for repairing a defect in a tubular structure, comprising:

• a body for insertion in said tubular structure;
• an end effector mounted to said body, said end effector having a weld torch operable to deposit weld material on said tubular structure by forming molten weld droplets and depositing said weld droplets onto said tubular structure;
• an extendable locking actuator for selectively contacting said tubular structure and anchor said locking actuator to fix the position of said end effector with respect to the tubular structure;
• and
• a drive unit comprising:
• a first brace for selectively securely engaging the tubular structure to anchor the apparatus;
• at least one linear actuator for moving said apparatus relative to said first brace in a direction along the longitudinal axis of the tubular structure;
• and
• a rotational actuator coupled to said end effector for rotating said weld torch.

A method of repairing a defect in a tubular structure, comprising:

• inserting an apparatus in said tubular structure, said apparatus comprising a body, an end effector mounted to said body comprising a wire electrode, said end effector having a weld torch operable to deposit weld material on said tubular structure by forming molten weld droplets and depositing said weld droplets onto said tubular structure, and an extendable locking actuator for selectively contacting said tubular structure and anchor said locking actuator to fix the position of said end effector with respect to the tubular structure;
• selectively contacting said tubular structure and anchoring said extendable locking actuator to fix the position of said end effector with respect to the tubular structure;
• forming a molten droplet of weld material on said wire electrode;
• oscillating said wire electrode to detach said droplet of weld material as the electrode retracts from the tubular structure;
• and
• depositing said weld droplet onto said tubular structure.