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PIPELINE INSPECTION GAUGE
A Pipeline inspection gauge or pig in the pipeline industry is a tool that is sent down a pipeline and propelled by the pressure of the product in the pipeline itself. Also known as an Inline Inspection (ILI) tool, it is the chief device used in pigging.
The original pigs were made from straw wrapped in wire used for cleaning. They made a squealing noise while traveling down the pipe that sounded to some like a pig squealing; the term "pipeline inspection gauge" was later created as a backronym.
One kind of pig is a soft, bullet shaped polyurethane plug that is forced through pipelines to separate products to reduce mixing. There are several types of pigs for cleaning. Some have tungsten studs or abrasive wire mesh on the outside to cut rust, calcium, or paraffin deposits off the inside of the pipe; others are plain plastic covered polyurethane.
Inline inspection pigs use various methods for inspecting the condition of a pipeline. A sizing pig uses one (or more) notched round metal plates that are used as gauges. The notches allow different parts of the plate to bend when a bore restriction is encountered. More complex systems exist for inspecting various aspects of the pipeline. Intelligent pigs, also called smart pigs, are used to inspect the pipeline with various sensors and record the data for later analysis. These pigs use technologies such as MFL (Magnetic Flux Leakage) and ultrasonics to detect the various aspects of the pipeline. 'Intelligent' or 'smart' pigs may also use calipers to measure the inside geometry of the pipeline.
The first smart pig was run in 1964. This inspection tool used MFL technology to inspect the bottom portion of the pipeline. The recording system used a flight data recorder black box to store the information.
A pig has been used as a plot device in three James Bond films: Diamonds Are Forever, where Bond disabled a pig to escape a pipeline, The Living Daylights, where a pig was modified to secretly transport a person through the Iron Curtain, and The World is not Enough, where a pig was used to move a radiological weapon through a pipeline.
[edit] See also
[edit] External links
[edit] Smart Pig Companies
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