Weld Purging short pipe pieces and dome-end welds where tandem Inflatable Tube and Pipe Purging Systems are unsuitable, Huntingdon Fusion Techniques HFT® manufactures Weld Purge Dams.
Ron Sewell, Chairman for HFT® said: “When welding tubes and pipes, the most cost- effective solution is to restrict the volume, usually with a Tandem Weld Purging System, especially welding metals such as stainless steels, titanium and zirconium.”
“Where Tandem Weld Purging Systems are unsuitable, Weld Purge Dams are available for pipe diameters from 6 to 88” (150 mm up to 2,235 mm) and offer a low-cost alternative to foam or cardboard dams that are still frequently handmade by welders on site. Unsuitable materials can often lead to rework of some kind and in worst cases cause welds to be rejected. Displacing the oxygen with an inert gas before, during and after welding helps to create welds that are free from oxidation. However the Weld Purge Dams should be made of materials that do not outgas water vapour or any other undesirable gases.”
Weld Purge Dams are manufactured with four pull tags located around the circumference, thus providing ease of positioning and retrieval. They are fitted with a dual inflation and purge hose, an additional purge gas hose and an exhaust vent which can be connected to one of the HFT® Weld Purge Monitors®. The additional purge gas hose is suitable for introducing extra purge gas into the weld zone at any time to cool welds, to meet interpass temperature specifications, or to provide more inert gas in the event of titanium, zirconium or special stainless applications needing a guaranteed zero colour weld.
Apart from the benefit of having a metallurgically sound weld, the difficulties of cleaning an oxidised weld are eliminated, saving vast amounts of money in labour and material costs as well as the disposal costs when pickling acids are used. Now there is no more reason to put welds at risk by using cheaper unsuitable materials, when for a very low cost Argweld® Inflatable Weld Purge Dams can be purchased instead!
Huntingdon Fusion Techniques HFT®’s White Paper: Single Ended Purge Dams is available to read on their website: https://www.huntingdonfusion.com/index.php/en_gb/technical-support/white-papers-40017/2868-wp-207-single-ended-purge-dams