The reduction of pig speeds can be required for reasons such as safety, cleaning efficiency, or to maintain normal pipeline flow rates without having to reduce line volumes when pigged.

Gas or fluids bypass through the annulus of the pig’s body and through variable ports in the front and sides of the pig’s nose. An onboard computer, reacting to input from odometer wheels, regulates the pig's vane positions and therefore the amount of bypass. As more bypass occurs, speed is controlled relative to line velocity, within predetermined parameters.

The electronics package includes a P2D PET data logger, which records vane position, differential pressure, temperature, X, Y, Z orientation and other vital data that defines the behaviour of the pig.

Inline recently ran its 42 inch and 36 inch tools in five sections of high-velocity gas lines. These lines operate under a special 80 per cent specified minimum yield strength rule, and slowing down throughput to perform required maintenance costs the operator a substantial loss of revenue. On a recent 36 inch diameter, 90 km pipeline run, gas flow averaged 19.3 km per hour and the SCP maintained a speed of 8–9.6 km per hour with the bypass vane system opened at 50 per cent.

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The Speed Control Pig (SCP) also has the ability to tow in-line inspection tools at speeds that will allow more reliable data to be recorded. The pig can also be used as an enhanced cleaning tool on lines that have black powder. The bypass moving through the pig exceeds the entrainment velocity of the debris, and assists in suspending the material out in front of the pig.

Inline is based in Tomball Texas and supplies built-for-purpose cleaning pigs, quality pigging equipment and pipeline maintenance management and advice.