Friday, April 23, 2010

Hydrautically Activated Pipeline Pigging

Another method of pipeline pigging is by using the principle of pressure drop or in other words a Hydrautically Activated Pipeline Pigging (HAPP). The pressure drop is created by blocking the pipeline fluid flow through a by-passable PIGs. The blockage will cause the pressure drop to accelerate the pipeline fluid flow to pass through pig cleaning head. The accelerated pipeline fluid flow will be directed onto the inner wall in front of the PIG to remove all kind of deposits that sticks on the inner wall surface of the pipeline. Using this method, it is like transforming the kinetic energy of the pipeline fluid into a locally available differential pressure which in other words creating a cleaning jets for the PIG.

The components or units that are involved in the HAPP PIG train consists of:
1) Brake Unit
2) Seal Unit
3) Cleaning Head

The PIG train will have an openings that will allow the entire fluid flow through the pipeline to bypass. The Brake Unit will ensure that the Hydrautically Activated PIG to be held back against the fluid flow direction in the pipeline. The fluid that passed through the Brake Unit will then be pushed against the Seal Unit which will channel the fluid flow into the openings located on the Cleaning Head. The situation of blockage made by the Seal Unit and the Brake Unit will cause the pressure difference in the fluid flow itself. The accelerated fluid that enters the cleaning head will be exiting the Cleaning Head through the nozzle to create extremely powerful liquid jets. This powerful liquid jets will be directed to the inner wall of the pipe and this fluid jets will have enough ability to remove any deposits in the pipeline. The Purpose of placing the Brake Unit at the back of the PIG train is to ensure the speed of the Cleaning Head will be controlled that will allow the PIG to remove any deposits before entering the area. The deposit that has been removed by the Cleaning Head Jet Fluid will then be flushed downstream and the total removal of the deposits in the pipeline will reduce the risk or possibility of the PIG getting stuck in the pipeline during the clelaning process.

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