PIPELINE PEGGING PROCESS

Pipeline pigs are devices that are inserted into and travel throughout the length of a pipeline driven by a product low. They were originally developed to remove deposits which could obstruct or retard flow through a pipeline. Pigging in the maintenance of pipelines refers to the practice of using pipeline inspection gauges or 'pigs' to perform various operations on a pipeline without stopping the flow of the product in the pipeline. Pigs get their name from the squealing sound they make while traveling through a pipeline. These operations include but are not limited to cleaning and inspection of the pipeline. This is accomplished by inserting the pig into a 'pig launcher' - a funnel shaped Y section in the pipeline. The launcher is then closed and the pressure of the product in the pipeline is used to push it along down the pipe until it reaches the receiving trap - trap the 'pig catcher'. If the pipeline contains butterfly valves, the pipelines cannot be pigged. Ball valves cause no problems because the inside diameter of the ball can be specified to the same as the of the pipe. Pigging can be used for almost any section of the transfer process between, for example blending, storage or filling system. Pigging systems are already installed in industries handling products as diverse as lubricating oils, paints, chemicals, toiletries and food stuffs. Pigs are used in lube oil or painting blending: they are used to clean the pipes to avoid cross-contamination, and to empty the pipes into the product tanks ( or sometimes to send a component back to it tank). Usually pigging is done at the beginning and at the end of each batch, but sometimes it is done in the midst of a batch, e.g when producing a premix that will be used as an intermediate component. Pigs are also used in oil and gas pipelines: they used to clean the pipes but also there are "smart pigs" used to measure things like pipe thickness long the pipeline. Though some product can be lost when pig is extracted. They can also be used to separate different products in a multiproduct pipeline.