Pipeline Stopple Equipment for Line Stopping Applications

A stopple fitting is the branch connection, such as a line stop flange or tee, welded or bolted onto the pipe that provides access for inserting the folding or pivoting head linestop machine. It seals against the pipe once the stopple plug is set, forming a pressure-tight isolation point.

Stopples are the plugging devices, including folding heads, pivoting heads, and completion plugs, used to block flow inside a pressurized pipe during hot tapping and line stop operations. They enable maintenance, repair, and replacement work on active pipelines without service interruption.

Schallert manufactures line stop equipment covering pipe diameters from small branch connections up to 84 inches, including folding heads from 8 to 66 inches, pivoting heads for size-on-size stops, and jackscrew actuators sized to match each application, from 48 inches to 192 inches of stroke.

Folding heads insert through a reduced branch fitting and unfold once inside the pipe, allowing use of smaller taps, valves, and fittings for cost savings. Pivoting heads are a size-on-size solution better suited for high pressure, high temperature, or hazardous gas and chemical applications.

Ratings vary by component: folding head assemblies are rated up to 250 psi, pivoting heads up to 450 psi at 250°F, jackscrew actuators up to 350 psi, and completion plug setters up to 500 psi, allowing selection of equipment matched to the pipeline's operating pressure.

A bypass is required when the pipeline must remain in service during the stopple procedure, such as valve replacement or pipe section removal. This typically involves two line stop machines and bypass-equipped housings to divert flow around the isolated section while work is completed.