How PIG Launchers and Receivers Work

PIG launchers and PIG receivers, in simple terms, are sections of a pipeline that allow a PIG to enter and exit the pipeline. Generally they are funnel, Y-shaped sections of pipe which can be pressurized or de-pressurized and then safely opened to insert or remove PIGs.

Although PIG launchers and receivers are normally customized for a particular system, there are steps that are common to all systems. When using a launcher, For example, a pipeline operator closes the isolation valve and kicker when using a launcher. In a gas system, the vent is opened to let the launcher reach atmospheric pressure. When using a liquid system, the drain valve and vent valve are opened, allowing air into the system that displaces the liquid.  The PIG is loaded once the launcher is to 0 psi, the trap door is opened, and the vent and drain valves are also opened. After cleaning and lubricated the closure seals, the trap door is closed and secured. The operator then closes the vent valve and equalizes the pressure in the isolation valve.  Once it is reopened, the PIG is launched and the valves are closed again.

The PIG does its work and reaches the receiver, which will need to be pressurized. The bypass and isolation valves are fully opened, while the mainline valve is closed partway. When the PIG arrives at the receiver, the isolation and bypass valves are closed, but the drain and vent valves get opened. The trap then needs to be depressurized to 0 psi in order to let the PIG be removed.  When the closure and seals are cleaned and lubricated, the trap door gets shut and secured, and the receiver is returned to its original condition.

Professional Piping Services utilizes a full array of PIGs, PIG launchers, and PIG receivers, designed to help keep pipelines operating at peak performance levels.