Buitink Technology develops and manufactures inflatable weld purging systems – also known as backing gas systems, purge dams or purge bags – for the controlled application of shielding gas to the inside of tubes, pipes and other closed profiles during welding. Every system is custom-made: any diameter, any shape, and heat-resistant versions for continuous use up to 300°C.

Why weld purging matters

When welding stainless steel, titanium, duplex or other reactive metals, it is crucial to protect not only the visible side but also the root side of the weld from oxidation. Exposure to oxygen at high temperatures leads to discolouration, brittleness and increased risk of corrosion.

Backing gas (purge gas) prevents this by displacing oxygen from the welding environment with an inert gas such as argon. Proper purging keeps the quality of the weld optimal – both visually and mechanically – with no discolouration or ‘sugaring’ on the inside of the weld.

Our solution: custom inflatable purge dams

Buitink Technology supplies inflatable purge systems that quickly create a clean, oxygen-free welding environment on the inside of a pipe or tank. Two inflatable dams seal the pipe on either side of the weld seam, creating a small purge chamber that fills rapidly with argon. The systems are cleverly designed, rapidly deployable and withstand temperatures up to 300°C (572°F). They are reusable and suitable for any pipe diameter or shape.

Image: Heat-resistant backing gas systems

How does our weld purging system work?

1. The system is inserted into the tube on either side of the weld, or when welding thin sheets of stainless steel under the weld.
2. The inflatable elements are filled with shielding gas (usually argon), sealing the tube airtight.
3. The space between the elements is also filled with argon (or the space under the weld) – this is the zone where welding takes place.
4. During welding, the shielding gas keeps flowing to keep oxygen out.
5. After welding, the elements are emptied and easily removed.
6. The result is a super strong and safe weld!

Illustration: Section of inflatable purge bag for backing gas

Advantages of our weld purging systems

Designed with practice in mind, our inflatable weld purging systems offer clear benefits for both the welder and the final quality of the workpiece:

• Temperature resistant up to 300°C→Designed for use in close proximity to the welding arc, resistant to high heat.
• Hotter for a short time?→Higher peak temperatures for short durations are available on request – tell us your temperature profile.
• Efficient gas consumption→Only the welding zone is filled with shielding gas – no wastage.
• Faster working time→Fast to install and remove, reducing production time.
• High weld quality→No discolouration, no oxidation or ‘sugaring’ on the inside of the weld.
• Reusable and durable→Long service life and lower cost per weld thanks to robust construction.
• Tailor-made→Available for all pipe diameters, shapes and applications.

Available types of weld purging systems

Buitink Technology offers different types of inflatable purge systems, including:

• Tandem (dual-bladder) purge systems→Two connected inflatable purge dams for pipe welds – any diameter.
• Hot purge systems up to 300°C→With replaceable Kevlar wear layers and glass-fibre reinforced silicone fabric, for pre-heated pipe and welds close to the arc.
• Single-ended purge dams→For short pipes, bends, tanks, fittings and dished ends.
• Gas-tight seals & custom purge bags→Inflatable shut-off dams and purge bags built to your specification and geometry.

Application areas for weld purging systems

Our backing gas systems guarantee hygienic, strong and corrosion-resistant welded joints in the following sectors:

• Stainless steel and titanium piping systems→Pure TIG and orbital welding without oxidation, ideal for critical process piping.
• Apparatus engineering, tanks & pressure vessels→Reliable tightness and long-term durability at high pressures and temperatures.
• Food & pharmaceutical industry→Microbiologically safe welding seams according to HACCP and GMP guidelines.
• Semiconductor & high-purity installations→Ultra-clean orbital welds for gas and process lines.
• Chemical process plants→Optimal resistance to aggressive media and thermal shock.
• Energy & offshore sector (hydrogen, nuclear, oil & gas)→Guaranteed weld integrity under extreme conditions.

Commonly used shielding gases

Depending on the material and application, different types of shielding gas are chosen. Below is an overview of the most commonly used gases:

• Argon→The most widely used gas: inert, stable and suitable for almost all metals.
• Nitrogen→Good alternative for certain applications, but not universally applicable.
• Helium→Less common because of its price, but sometimes required for specific materials.

Hot purging: 300°C continuous – hotter on request

For pre-heated pipe (such as chrome-moly steels) and welds close to the arc we build heat-resistant purge dams with replaceable Kevlar layers, suitable for continuous use at up to 300°C. Higher peak temperatures for short durations are available on request – tell us your temperature profile and we will select and test the right material combination.

Custom-made where catalogues stop

Standard purge bag ranges cover round pipe in catalogue sizes. As developer and manufacturer in one, we design and produce systems that do not exist off the shelf: very large diameters, rectangular and oval sections, single-ended dams for tanks, dished ends and fittings, and customer-specific requirements for the nuclear, pharmaceutical, semiconductor and food industry.

Qualified for nuclear, vacuum and high-purity projects

Demanding projects ask more of a purge system than temperature alone. We support these requirements as standard practice:

• Verified material purity→Independent laboratory analysis (ICP-MS) of leachable halogens (chloride, fluoride, bromide) and total sulphur and phosphorus content.
• Halogen-free options→Halogen-free and low-halogen materials, including protective halogen-free cover layers.
• Low outgassing→Pre-baked, low-outgassing fabrics for vacuum and ultra-clean environments.
• Full documentation→Design reports, risk assessments, drawings and part lists, calculations, operation manuals, compliance matrices and factory acceptance test procedures to nuclear quality-assurance level.

Distributors wanted

We are expanding our European distributor network. Are you a welding supply specialist? Contact us for reseller conditions on a custom-made purging programme that standard suppliers cannot deliver.