A self contained low voltage electrical source provides power for the shielding gas, air control valves, ring drive and wire feed motors. The pneumatic system, also self contained, operates the travel motors, brakes, drive wheels, aligners, and front and rear clamping shoes. Manipulation of the internal welder is controlled by an operator at the end of a 40’/80’ Reach Rod by a control box or by the master control box located on the nose cone. The lightweight tubular Reach Rod contains the control cable, all welding leads, air line, gas charge hose, and battery charge cable.
The welding heads are located symmetrically around the rotating ring and perform the root pass welding from the inside. The number of welding heads on the IWM varies between four and eight depending on the machine’s size (most machines have six or eight).
The CRC-Evans IWM is the most productive system for pipeline root pass welding. On a 36” pipeline, the root pass welding arc time less than one minute. The internal root pass technique is also more tolerable to pipe mismatch (high/low) than any other external root pass technique.