Large Diameter Pipework Fabrications
Large diameter pipework can cause several challenges, especially when those pipes are manufactured from stainless, duplex and chrome steels, titanium or zirconium. When welding such reactive materials, they need to be purged of oxygen before, during and after welding.
It is not cost effective to completely fill pipework with expensive inert gas, so weld purging experts Huntingdon Fusion Techniques developed QuickPurge® Systems to dramatically reduce the space that needs to be purged.
Ron Sewell, Chairman for HFT® said: “Using QuickPurge® means there is no longer a need to fill complete pipework fabrications with an inert gas. These devices localise the gas purging to a space about 10” (250 mm) either side of the weld to reduce purging time dramatically, making huge savings in both purging time and gas costs.”
“They are so efficient that they pay for themselves in the first couple of welds in gas savings alone, whatever the pipe size. QuickPurge® is simply inserted into a pipe, inflated within, restricting the volume around the weld and removing the oxygen down to 30 ppm (parts per million) within minutes. For example, a 36” diameter stainless steel pipe can be purged ready for welding in under 32 minutes.”
Filling the tube with argon or purging with old-fashioned foam dams or other homemade devices will take many hours. Old-fashioned purge dams contain water vapour and air that outgas during the weld process causing oxidation that shows up as discolouration around the weld, which then needs to be cleaned with grinding tools, wire brushes, or chemical solutions causing an extra cost.