What is the primary function of a 'launching trap' in a pipeline pigging operation?

The primary function of a launching trap (also known as a pig launcher) in a pipeline pigging operation is to safely and efficiently insert a pipeline pig into the pipeline without interrupting the flow of product. A pipeline pig is a device that is inserted into a pipeline to perform various maintenance tasks, such as cleaning, inspection, or batch separation. The launching trap is a specialized pressure vessel that is connected to the pipeline at a designated launching point. It typically consists of a cylindrical barrel with a closure mechanism (e.g., quick-opening closure) that allows access to the interior. The pig is placed inside the launching trap, and the trap is then sealed. The pressure inside the launching trap is gradually equalized with the pressure in the pipeline. Once the pressures are equalized, the pig is released into the pipeline using a controlled mechanism, such as a kicker valve or a flow diverter. The flow of product in the pipeline then propels the pig down the pipeline. The launching trap allows for the safe and controlled insertion of the pig, preventing sudden pressure surges or damage to the pig or the pipeline. It also minimizes the risk of product leakage or environmental contamination. The design and operation of the launching trap are critical to the success of a pigging operation. Factors such as the pig size, pipeline diameter, operating pressure, and flow rate must be considered to ensure proper pig launching.