New Tube and Pipe Weld Purge Systems

Having been manufacturing Tube and Pipe Weld Purging Systems since 1975 Huntingdon Fusion Techniques (HFT) said it has evolved the science of Weld Purging to new levels.

Along with other recently announced scientific developments in its Weld Purge Monitor series, the Company has now reached the Fifth version of its Tube and Pipe Weld Purge System designs by launching the new PurgElite range of Tube and Pipe Weld Purging systems for diameters from 1” to 24” diameter inclusive.

These systems are suitable for marine industries, including shipbuilding, ship repair and offshore industries using tubes and pipes. In particular, PurgElite systems can be used in high quality tube and pipework where the internal surfaces may be polished to ensure minimum entrapment and low corrosion resistance. With the new Intacal specially designed in line purge valve and the synthetic hose protection, there are no metal parts to scratch the tube or pipe surfaces.

IntaCal needs no setting or controlling, but is precisely manufactured for the PurgElite method of weld purging.

This new range comprises 15 models for tube and pipe sizes from just under 1” to 24”, each one overlapping the range of the other so that all internal diameters from 20mm up to 610mm are covered.

The new series has a number of major advantages over previous weld purging systems and has taken into account the evolving technology in all market places where much higher specifications of materials and work finish are available and expected.

According to the manufacturer, the key feature is the development of an in line purge gas release valve that is required to purge the chamber between the two dams once they are inflated.

This leads to the advantages mentioned above, namely the ability to manufacture a 1” system; absence of protruding metal parts that scratch the insides of electro polished tubes and pipes; elimination of the burst bladder problems that occur with other systems; greater flexibility because the complicated valves still used by others, have been eliminated; faster purging using less of the expensive inert purging gas; no complicated valve to set and to malfunction and no loss of time at the start up of jobs and lower manufacturing cost

Other features of the PurgElite system include high tech, high temperature resistant, synthetic gas hose; glow strip positioning band; ease of pulling around bends and elbows in complex tube and pipework systems and selection of Low Vapour Pressure Materials.

Low Profile Valve
For the first time it is possible to locally purge 1” diameter tube and pipe welds with an inflatable tube and pipe weld purging system, instead of having to fill up complete systems with expensive inert weld purging gas. The 1” PurgElite Tube Weld Purging System will be a valuable welding accessory to manufacturers of many stainless steel, Titanium and Nickel Alloy tubular systems.

Absence of protruding Metal Parts
No scratching, particularly of expensive electro-polished tubes and pipes. Weld purging is mostly carried out on Stainless, Duplex and Chrome steels as well as Nickel and Titanium alloys.

When internal tube and pipe surfaces are scratched by metal parts on old fashioned weld purging systems, there will be a loss of corrosion resistance that cannot readily be repaired. As well as negating one of the critical purposes for which the material was selected, scratches cause interruptions to the flow of the gases or liquids inside and leave resting places where bacteria can multiply.

The absence of protruding metal parts with the PurgElite system completely minimizes the risk of scratching and damaging the insides of valuable tube and pipe systems.

Manufacturers of High Purity Systems and those with some other critical applications will use internally electro-polished tubes and pipes making the PurgElite system even more valuable and more essential to prevent scratching.

Elimination of burst bladder problems
Other types of inflatable pipe purging systems have large valves that are often set incorrectly leading to frequent problems of burst bladders. The new PurgElite system completely overcomes that problem with a different type of system completely, for inflation and purging.

Greater flexibility
The PurgElite system of Tube and Pipe weld purging systems, has eliminated the old style inflexible metal braided hose and substituted it for a new technology high temperature resistant, flexible gas hose protector connecting the two purge dams.

This high temperature resistant weld purge hose protection material is heat resistant up to 700 degrees. In the event of hot liquid metal droplets falling on the hose protection, its intumescent properties make a heat barrier to prevent damage to the purge hose, thus avoiding the risk of loss of purge quality and the potential loss of a weld joint.

The greater flexibility of the systems with this non metal hose gives operators the freedom to pull PurgElite systems around tight bends and through complex tube and pipe fabrications.

Faster weld purging
With the smaller volume, simple gas release valve that uses mathematically calculated designs, the purge gas will be released faster and in greater quantities permitting fast purging of the volume below the weld, without creating the turbulence and long purge times associated with other devices.

When used with one of the PurgEye Weld Purge Monitors the PurgElite systems provide the operator with the perfect combination to purge and monitor oxygen content to achieve the fastest and most ideal conditions for welding to begin.

The savings made by using less of the expensive inert purging gas, along with the savings achieved with shorter purging time, will help to pay for these products in just one weld.

No complicated valve to set and no loss of time at the start up of jobs.

The specially designed PurgElite valve system allows operators to use their systems immediately without having to follow complicated valve setting procedures. Such work causes loss of production time and invariably leads to errors and failed systems.

The PurgElite systems are totally and simply plug and play. Plug in the inert gas supply and purge the weld, more than halving set up time.

Lower manufacturing cost
The new low profile, mathematically designed PurgElite gas purge valve is a single in line item that replaces a costly valve with elbow fittings and other connectors that may even separate during welding. In addition, the high temperature resistant flexible connection hose replaces and expensive metal braided hose with costly fittings. Summed together, these savings allow HFT to bring the PurgElite range to the market place for lower costs than ever before.

High temperature resistant hose
The heat buildup in the welding cavity is such that the gas hose connecting the two dams has to have a high temperature resistance. PurgElite weld purge systems have a newly developed synthetic material capable of withstanding a temperature of 700º C (1,300º F) that will withstand even hot metal dropping on it by building an intumescent layer.

Replaceable glo strip band
Once PurgElite systems are inside a tube or pipe system, they can be pulled around from Joint to joint and positioned correctly and easily. This has been made possible by the fluorescent glo strip fitted to the centre of the purging system. Welders can see through the pipe joint into the internal dark area, whether clamped or tacked ready for welding and view the purge system as it comes into place, with the replaceable glo strip immediately below the weld.

Low vapor pressure materials
Employing latest material developments (HFT) has selected lower vapor pressure materials to ensure that the outgassing rate into the weld zone will be reduced to the barest minimum during welding to protect the molten weld pool from oxidation and the problems arising.

For larger diameters of pipes, Huntingdon Fusion Techniques Limited manufactures its rugged Argweld Quick Purge Systems to suit diameters from 8” to 80” (200-2,000mm).

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