Pigging in the context of pipelines refers to the practice of using devices known as "pigs" to perform various maintenance operations. This is done without stopping the flow of the product in the pipeline.

These operations include but are not limited to cleaning and inspecting the pipeline. This is accomplished by inserting the pig into a "pig launcher" (or "launching station") — an oversized section in the pipeline, reducing to the normal diameter. The launching station is then closed and the pressure-driven flow of the product in the pipeline is used to push the pig along down the pipe until it reaches the receiving trap — the "pig catcher" (or "receiving station").

Pig Launcher/Receiver

Pig launchers and pig receivers are installed on pipelines to launch and receive pipeline pigs, pipeline spheres and pipeline inspection tools. Pig launchers & pig receivers offer a safe and effective means of inserting and removing pipeline pigs to and from pipelines. We fabricate pig launchers and pig receivers to meet the specific requirements of a pipeline.

Our in-house design, engineering, fabrication and testing capability is used to produce all types of pig and sphere launching and receiving systems.

The pig launchers and pig receivers we fabricate range from simple barrel pig launchers and receivers through to complete skid mounted units with associated equipment including actuated valves, quick opening closures, instrumentation, pig signalers and control systems.

The pig launchers and receivers we fabricate are suitable for onshore, offshore and subsea pipelines. All units are designed and fabricated to relevant required pipeline and vessel design codes including:

• ASME U Stamp
• ASME VIII
• NACE
• ASME B31.3, B31.4, B31.8

Quick Opening Closure

Quick opening closures are pressure retaining structures designed to provide access to pipelines and pressure vessels that provide safe and quick access to pipeline and pressure vessels. They are built to meet all required international design codes and can be used in horizontal, vertical, inclined or declined applications.

ASME VIII Div.1.states that "Quick-actuating or quick opening closures are those that permit substantially faster access to the contents space of a pressure vessel than would be expected with a standard bolted flange connection

Typical applications for the Quick Opening Closure include

• Pig launchers and pig receivers
• Filter vessels
• Metering skid systems
• Strainers
• Separators

Pig Signaller

Pig signallers are fitted to launcher and receiver units to confirm the launch / arrival of a pig. They can also be at any location along the pipeline length to give indication of a pig at a specific location. They can be used to detect the passage of all types of pigs from foams, spheres and metal bodied pigs to intelligent inspection tools.

A proximity switch can also be installed on the pig signaller, that can send a signal to the Control Room, which can be used as inputs for other actuated valves along the pipeline.

SDV supplies pig signallers in three main configurations;

1. Boss mounted (non-removable)
2. Flange mounted (non-removable under pressure, removable when isolated)
3. Flange mounted with isolation valve (removable, even under line pressure)

These signallers are in various configurations, i.e.

• ANSI Class 150lbs, 300lbs, 600lbs, 900lbs, 1500lbs, 2500lbs
• Body material in Carbon Steel, High Temperature Steel, Stainless Steel, Duplex