Inflatable purge bladders seal the pipe either side of the weld joint, so you purge a small chamber instead of the whole line. That means less argon, shorter purge times and a cleaner root. This guide walks through choosing a system and purging with it, using Aquasol I-Purge and I-Purge X systems as the example.
Choose the right system
| Aquasol I-Purge (ABLD) | Aquasol I-Purge X (XABLD) | |
|---|---|---|
| Sizing | One system per pipe size, 2–70 in. | Nine adjustable ranges, 2–70 in. |
| Best for | Repeat work on one pipe size | Work that moves between sizes |
| Spares | Modules and harnesses sold separately | Modules and harnesses sold separately |
See the I-Purge and I-Purge X size tables. For one-sided isolation or closing a pipe end, use an inflatable pipe stopper instead.
What is in the system
- Two bladder modules (Module A and Module B) with spark-resistant covers.
- High-heat bridge harness joining the modules and keeping them out of the heat-affected zone.
- Blue hose — inflates the bladders, then feeds purge gas to the weld zone.
- Black hose — a direct purge path to speed oxygen removal.
- White hose — exhaust connection for an oxygen monitor.
- Relief valve and gas diffuser — limit inflation pressure and spread the gas evenly.
Step by step
- Clean the pipe where the bladders will seal.
- Choose the harness length. The standard harness suits most work; use an extended high-heat harness for preheat or high-temperature procedures.
- Position the system so one module sits either side of the joint, using the pull loops. The harness can route through elbows and tees.
- Inflate through the blue hose. The relief valve limits pressure and holds the seal against the pipe wall.
- Purge. Gas flows through the diffuser into the sealed chamber; open the black hose for a direct purge path.
- Check the oxygen level at the white exhaust hose with a weld purge monitor, and weld once it is below your procedure’s limit.
- Weld, keeping the purge running through the root pass.
- Deflate and remove the system with the pull loops. Inspect it and replace any worn module.
Frequently asked questions
How far from the weld should purge bladders sit?
Far enough to stay out of the heat-affected zone. The high-heat harness sets the spacing; use an extended harness (24 to 72 in., or custom) for preheat or high-temperature work.
I-Purge or I-Purge X?
I-Purge systems are sized to one pipe diameter and suit repeat work on that size. I-Purge X systems expand to cover a range — nine sizes cover 2 to 70 in. — and suit work that moves between pipe sizes.
Bladders or water-soluble dams?
Bladders are reusable and can be pulled out after welding. Water-soluble dams are single-use but suit places a bladder cannot be retrieved from; they dissolve when the line is flushed.
Do I need an oxygen monitor?
If your procedure sets an oxygen limit, yes. Purge time alone does not prove the oxygen is gone.
Compare Aquasol purge bladder systems or request a quote — call 1-866-277-0661.