When stainless steel, duplex steels or titanium pipes need to be welded in the process industries, they generally have to be purged of air and water vapour, in order to obtain the quality of weld demanded by such industries.
Today, more than 40 years after high quality pipe weld systems were developed, welders are still carving crude discs out of sponge foam without understanding the characteristics of such equipment. Most sponge foam products are open cell materials, which allow gas to pass through, so as fast as the inert purge gas is pushing the air out of one end of a pipe, oxygen and water vapour is entering at the other end.
For pipes above 6” diameter, Huntingdon Fusion Techniques (HFT) offers QuickPurge® Systems, which are simply inserted into a tube or pipe, placed in position with one dam either side of the weld, inflated within the pipe thus restricting the area that is to be purged and removing the oxygen within minutes.
All of the QuickPurge® systems are manufactured as standard with a hose for connecting a Weld Purge Monitor®, which can read oxygen levels down to as low as 1 ppm (accurate to 10 ppm).
Photo Courtesy of Huntingdon Fusion Techniques