Mastering the art of welding high-quality pipes involves more than just a steady hand. The secret to achieving a perfect, contamination-free weld often lies in the preparation, specifically in the method used for pipe purging. Selecting the right technique can significantly enhance efficiency, decrease gas consumption, and ensure the final weld meets stringent quality standards.
While the goal is always to displace oxygen with an inert gas, the methods to achieve this vary. Different projects call for different approaches.
Here, we explore five effective pipe purging techniques and the specialist equipment that enables them, helping you select the best method for your next welding project.
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Inflatable Twin Bag Systems
One of the most popular and efficient pipe purging techniques involves using an inflatable system. These consist of two inflatable dams connected by a flexible tube, creating a sealed chamber around the weld joint. The system is positioned inside the pipe, inflated to create a tight seal, and then the space between the dams is purged with inert gas.
This method is incredibly fast and cost-effective. By localising the purge to a small area, you drastically reduce both the volume of expensive inert gas needed and the time spent waiting for oxygen levels to drop.
Best for: A wide range of pipe diameters and repetitive welding tasks.
GBC UK Solution: Our Inflatable Purging Systems are designed for rapid deployment and create an excellent seal, making them a go-to choice for welders looking to boost productivity.
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Reusable Silicon Double Seal Systems
For workshops that handle frequent pipe welding, reusable systems offer excellent long-term value. This technique uses two durable, heat-resistant silicon discs connected by a rigid spine. The system is pushed into position, and the flexible outer edge of each disc creates a firm seal against the pipe wall.
The space between the discs is then purged. These systems are robust, capable of withstanding high temperatures, and can be used hundreds of time, making them a sustainable and reliable investment. Their rigid design also ensures easy and precise positioning within the pipe.
Best for: High-volume fabrication shops and projects requiring consistent, repeatable results.
GBC UK Solution: Our Double Seal Silicon purging systems are designed for durability and performance, providing a long-lasting solution for achieving perfect welds consistently.
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Water-Soluble Purge Dams
What happens when you cannot retrieve a physical purging system from the pipe? This is where water-soluble materials provide an ingenious solution. This technique involves creating purge dams from a special biodegradable paper and water-soluble adhesive tape.
You construct two dams and fix them inside the pipe on either side of the joint. After purging and welding are complete, the entire system is simply flushed out with water or steam, dissolving completely and leaving no residue. This eliminates the need for retrieval, which is ideal for complex pipework or closed systems.
Best for: Intricate pipe systems, U-bends, and applications where dam retrieval is impossible.
GBC UK Solution: GBC UK’s Water Soluble Purging Products offer a flexible and effective method for creating a reliable purge chamber that disappears on command.
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Inflatable and Expanding Pipe Stoppers
Sometimes, the task is not to purge a small joint but to block an entire pipe opening or create a custom purge setup. For these scenarios, single stoppers are the perfect tool. This technique involves using an inflatable or mechanical stopper to seal one end of a pipe section, allowing the entire length to be purged.
Inflatable stoppers are versatile and can fit a range of sizes, while expanding stoppers provide a powerful mechanical seal for high-pressure applications. They can also be used in pairs to create a custom purge chamber over long distances.
Best for: Blocking off pipe ends, leak testing, and creating large-volume purge environments.
GBC UK Solution: Our range of Inflatable Pipe Stoppers and Expanding Pipe Stoppers provides a robust and secure way to seal pipes for any purging or testing requirement.
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Root Gap Taping
The final technique is less of a standalone system and more of a vital supporting method. To ensure the integrity of any purge, you must seal the root gap on the outside of the pipe. This prevents the valuable inert gas from escaping and, more importantly, stops oxygen from being drawn into the weld zone.
Using a specialised, high-temperature aluminium tape to cover the exterior joint line is a simple but critical step. The tape adheres securely and can withstand the heat of welding, ensuring your carefully controlled atmosphere remains stable throughout the process.
Best for: All pipe purging applications as a supplementary technique to ensure a perfect seal.
GBC UK Solution: Our high-quality Purging Tape is essential for any professional welder’s toolkit, providing the final seal needed for a flawless pipe purging operation.
Choose the Right Technique for a Perfect Weld
The success of your welding project depends on effective pipe purging. By understanding these five techniques, you can select the most suitable method for your application, saving time and fuel, and ensuring superior weld quality.
If you are unsure which pipe purging technique is right for you, our team of experts is ready to help. Contact GBC UK to find your ideal purging solution.
Phone: 01844 201 555
Email: sales@gbc-uk.com