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From simple expandable plugs to fully integrated in atable devices the products can accommodate pipe sizes from 10 to 2,500 mm.
Expandable Plugs are a popular choice and these are available with nylon, steel and aluminium bodies. Surrounding each body is a exible seal that can be expanded by applying a radial force through a manually operated wing nut on the shaft.
These mechanical plugs can be used for purging pipework fabrica- tions where a variety of openings are present and where it is easier to purge the complete assembly.
In atable Weld Purging Systems
have been developed to help speed up the welding process for engineers involved in the fabrica- tion of pipes and tubes.
The revolutionary PurgElite® range, manufactured by Hunt- ingdon Fusion Techniques, is a robust, easy to use, welding ancillary that offers considerable savings in time and inert gas.
Two in atable dams are connected by a synthetic exible hose that will not scratch the inside of pol- ished tube or pipe work. The hose is made of a self-sealing intumes- cent material that resists even hot metal being dropped on it and will not disturb the purge gas ow.
The QuickPurge® Family of In atable Tube, Pipe and Pipe- line Systems have been designed for pipe welding between 6 and 88” (150 and 2,235 mm). Both PurgElite® and QuickPurge® products are multi-use systems and include high temperature options for pre- and post- weld operations up to 300oC.
Weld Trailing Shields®
Expandable plugs and in atable
purge systems meet the require- ments for protection of the weld root during tube and pipe welding: trailing shields are available for the topside.
They can provide a high level of additional inert gas shielding to supplement that supplied by the basic welding torch. Shields are available to match a wide variety of forms from at to diameters as small as 25 mm. Both internal and external models are available
Flexible Welding Enclosures®
For component welding, Flexible Enclosures overcome all the dis- advantages of glove boxes and vacuum systems but at a fraction of the cost. They occupy consider- ably less oor space and all parts of the welded component nish bright and shiny with no oxida- tion or discolouration. Argon gas costs are reduced signi cantly and cleaning costs are eliminated.
Controlling Purge Gas Quality
Using specialised weld purging equipment does not guarantee defect free welds. Control of the oxygen content of the purge gas is crucial to success and a monitor that measures residual oxygen content reliably and accurately at the low levels considered is nec- essary when welding zirconium alloys.
These instruments are capable of measuring oxygen content accu- rately as low as 10 ppm - more than adequate to satisfy the residual oxygen recommended for zirconium alloy welding.
REFERENCES
Developments in End Closure Welding Technology for Zircaloy Clad Fuel Elements. Amota I and Carena G, Energia Nucleari 17 (1970)
Welding zirconium and zirconium alloys
The most ef cient method of ensuring high quality inert gas coverage is to use exible enclosures. They are available in sizes approaching 30 cubic metres with residual oxygen content as low as 10 parts per million.
Sutherlin R, Tube and Pipe Journal, September 2016
FURTHER INFORMATION
Welding of zirconium alloys Komuro K, Welding International, 1994 (2)
Guide for the fusion welding of zirconium and zirconium alloys AWS G2.5/G2.5M: 2012, January 2012
Huntingdon Fusion Techniques Ltd in the UK can provide the following detailed information on request: Technical Notes; Expandable Plugs, PurgElite® Systems, Trail- ing Shields, QuickPurge® Systems, Flexible Welding Enclosures®, Weld Purge Monitors®.
Technical Papers
Huntingdon Fusion Techniques
Stukeley Meadow SA16 0BU Carms, UK
Tel.: +44 1 554 836 836 Fax.: +44 1 554 836 837
hft@huntingdonfusion.com www.huntingdonfusion.com
ITAtube Journal No2/July 2018
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