Inflatable stoppers come in many shapes, sizes, materials

The Pipestoppers® Division of Huntingdon Fusion Techniques HFT® offers the Inflatable Pipestopper® in standard and nonstandard models for reducing volume or blocking pipes, tanks, and other circular orifices for purging, routine maintenance, or to prevent the entry of foreign bodies.

Available in the U.S. from Cob Industries, the product can be used to provide a strong barrier in pipeline activities to prevent foreign bodies entering the line during downtime. In machining applications, it can be inserted below a horizontal flange on a vertical pipe to prevent machining fluid, swarf, and tools from falling into expensive machinery such as pumps and turbines.

For welding large tanks and vessels, a stopper inflated with air can reduce the volume inside, so that the argon-purging process takes little time and uses a minimal amount of gas.