Pipe welding purging systems specialist Huntingdon Fusion Techniques (HFT) has introduced the PurgElite low-cost range of tube and pipe purging systems to achieve a clean, oxide free, zero colour weld in tubes and pipes, which can be used in any other industry where stainless steel or titanium is used.

HFT CEO Georgia Gascoyne mentions that welds in tubing and pipework for vacuum systems need to be manufactured from stainless steel, should be leak tight, the joints should have full penetration with excellent sidewall fusions, there should be no porosity, and the finish should be free from oxidation and discolouration.

“When welding these stainless steel tubes and pipes, it is important to purge the welding zone with an inert gas, usually argon, to prevent loss of corrosion resistance, oxidation, discolouration, metallurgical defects and to ensure a good internal weld profile,” he says.

PurgElite has been designed to save welders the expense of completely filling tubes and pipes with an inert gas.

PurgElite systems with double inflatable dams are available, manufactured to suit pipe diameters from 25 mm to 600 mm. Gascoyne points out that PurgElite is manufactured with a special spinal tube, joining two inflatable dams, that is resistant to hot metal up to 300 °C and is superflexible to allow movement around 90 ° bends. These pipe weld purge systems are made of low outgassing rate materials, which gives them the ability to produce the right environment for high-quality welds.

He says that to ensure the PurgElite System can be positioned accurately inside the tube or pipe, a centrepiece glow positioning indicator called RootGlo comes as standard on all sizes of the PurgElite system.

The PurgElite has suitable sizes for various industries that require precision welding like the pharmaceuticals, dairy, food and beverages, biochemicals processing, nuclear and semiconductor industries. He points out that these industries require high-precision welds, and contaminants that could be left in the pipe system after welding have to be minimised.

Further, Gascoyne points out that IntaCal, a purge gas feed device, removes the need for a complicated valve system and that the company’s PurgeGate valve is available as an accessory. The PurgeGate valve regulates the gas flow and pressure during welding to ensure the inflatable dams do not burst resulting in a failed weld.

Along with the IntaCal gas feed device, PurgeGate valve and the PurgElite inflatable dams HFT has the QuickPerge system, the HotPurge, weld purge dams and the one way valves that offer easier ways to keep welds isolated from oxygen and ensure high-quality welds.

“Heat resistant covers are available as accessories to protect the inflatable dams in the event that the weld process is unusually hot. These covers suit any inflatable purging or blocking system and are held onto each dam by a number of ties. Such covers allow use up to a temperature of 300 °C,” he concludes.