Patent ID: 8530777

Claim:
Welding system for tubular workpieces, comprising: a welder power supply, the welder power supply being connectable to an orbital weld head for providing electrical power during a welding operation; a first automatic flow control for purge gas, said first automatic flow control comprising an inlet connectable to a source of purge gas and an outlet for providing a flow of purge gas to an outer diameter (OD) region of a weld site for tubular workpieces; said first automatic flow control controlling flow rate of purge gas to said outer diameter (OD) region of the weld site during an orbital welding operation; a second automatic flow control for purge gas, said second automatic flow control comprising an inlet connectable to a source of purge gas and an outlet for providing a flow of purge gas to an inner diameter (ID) region of a weld site for tubular workpieces, said second automatic flow control controlling flow rate of purge gas to said inner diameter (ID) region to maintain a desired ID purge gas pressure during a welding operation; said second automatic flow control for purge gas comprising an automatic ID purge control, said automatic ID purge control comprising a pressure sensor that detects ID purge gas pressure, said automatic ID purge control adjusting flow rate of purge gas to maintain said desired ID purge gas pressure at the weld site during a welding operation; said second automatic flow control for purge gas comprises a mass flow controller, said second automatic flow control for purge gas adjusting flow rate of purge gas from said mass flow controller to said ID region based in part on a signal from said pressure sensor during a welding operation.