Welding purge control using electronic flow control

Abstract

A purging arrangement for a welding system uses automatic flow control function, such as an MFC, to control purge gas flow rate and/or pressure at the weld site.

1 - 13 . (canceled) 
     
     
         14 . Welding system, comprising:
 a welder power supply, said welder power supply being connectable to an orbital weld head for providing electrical power during a welding operation.,   at least one mass flow controller,   a control system operably coupled to said at least one mass flow controller, said control system being configured to control flow rate of a purge gas from said mass flow controller,   a housing that encloses said power supply, said at least one mass flow controller and said control system.   
     
     
         15 . The welding system of  claim 14  wherein said housing comprises a handle that can be manually grasped for portability of the welding system. 
     
     
         16 . The welding system of  claim 14  wherein said control system is operably coupled to said welder power supply and inhibits a welding operation until a purging operation starts. 
     
     
         17 - 20 . (canceled) 
     
     
         21 . A method for controlling purging during a welding operation, comprising:
 performing a butt welding operation on end to end abutting tubular workpieces using an orbital welder,   applying a flow rate profile for purge gas to either an outer diameter region or an inner diameter region at the weld site,   said flow rate profile comprising at least a first flow rate before a welding operation begins and a second flow rate during the welding operation with said second flow rate being lower than said first flow rate.   
     
     
         22 . The method of  claim 21  wherein said step of applying a flow rate profile for purge gas to either an outer diameter region or an inner diameter region at the weld site comprises a third flow rate after the welding operation ends with said third flow rate being higher than said second flow rate. 
     
     
         23 . The method of  claim 21  wherein said step of applying a flow rate profile includes using an electronic automatic purge control. 
     
     
         24 . The method of  claim 21  wherein a welding operation is automatically inhibited until purge gas is flowing to the weld site. 
     
     
         25 . The method of  claim 21  wherein said step of applying a flow rate profile includes using a mass flow controller. 
     
     
         26 . A method for controlling purging during a welding operation, comprising:
 performing a butt welding operation on end to end abutting tubular workpieces using an orbital welder,   applying a flow rate profile for purge gas to either an outer diameter region or an inner diameter region at the weld site,   said flow rate profile comprising at least a first flow rate during a welding operation begins and a second flow rate after the welding operation ends with said second flow rate being higher than said first flow rate.   
     
     
         27 . The method of  claim 26  wherein said step of applying a flow rate profile for purge gas to either an outer diameter region or an inner diameter region at the weld site comprises a third flow rate before the welding operation begins with said third flow rate being higher than said first flow rate. 
     
     
         28 . The method of  claim 26  wherein said step of applying a flow rate profile includes using an electronic automatic purge control. 
     
     
         29 . The method of  claim 26  comprising the step of electronically confirming that purging is functioning properly prior to enabling a welding operation. 
     
     
         30 . The method of  claim 26  wherein said step of applying a flow rate profile includes using a mass flow controller. 
     
     
         31 . 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;   at least one automatic flow control for purge gas, said automatic flow control having an inlet connectable to a source of purge gas and an outlet for providing a flow of purge gas to an outer diameter region of a weld site for tubular workpieces within the orbital weld head; said automatic flow control applying a flow rate profile for purge gas to either an outer diameter region or an inner diameter region at the weld site,   said flow rate profile comprising at least a first flow rate before a welding operation begins and a second flow rate during the welding operation with said second flow rate being lower than said first flow rate.   
     
     
         32 . The welding system of  claim 31  wherein said flow rate profile comprises a third flow rate after the welding operation ends with said third flow rate being higher than said second flow rate.