Liquid recovery systems, also known as ‘pigging’, are common in plants and factories that process liquids, such as in food and drink production, pet food, cosmetics, paints, and personal care products. The aim of pigging systems is to recover and remove leftover liquids from pipelines, using a special projectile known as the pig. Because of its efficiency in removing large volumes of residual liquid, pigging is regarded as cost-effective, with less need for repeated CIP cycles, cleaning chemicals, and waste disposal.
While the pig is an important component in the pigging system, it is by no means the only one. Pigging systems, both single-pig and double-pig, comprise many parts that contribute to its effectiveness, efficiency, and safe operation.
The Components In A Pigging System
Processing plants and factories differ enormously, so pigging systems are usually custom designed and built to meet the needs of each customer.
However, most systems tend to feature the same components:
The most important component, the pig, has a diameter slightly wider than the pipeline it is clearing, typically between one and eight inches. Propelled by water, carbon dioxide, or compressed air, the pig travels through the pipelines, removing remnants of the previous product – which can often be reclaimed.
Also known as the pig sensor or signaller, the pig detector identifies the location of the pig in the system. Detectors are usually externally mounted on the pipe that is being cleaned, close to the launch and receive stations.
Pigging Control System
Control software is essential in partially or fully automated pigging systems, to facilitate efficient, safe, and reliable operations. The control system, which manages the movement of the pig through the pipework, is usually controlled by PLCs with SCADA or HMI systems, and is either integrated into the existing configuration or added as a standalone feature.
Launch And Receive Stations
The launchers and receivers are vital components in the pigging system. The launcher delivers the pig into the pipework and propels it through the line, while the receiver collects and returns it to the launcher. Usually designed specifically for the system, these components feature special valves for precise control of the pig.
When not in use, the pig is stored in the pig housing, which is usually located at the launch station.
Valves are essential for the smooth operation of the pigging system and play different roles. Some are used as on/off valves, while others control the direction of the pig through the pipelines.
It almost goes without saying but pipework is a key component in pigging systems. It must be in excellent condition, with no damage or dents that could affect the movement of the pig.
Contact Us For All Your Pigging System Components
At Industrial Trading Solutions, we stock a range of product retrieval and pigging components – and can help you select the right parts and configuration when designing a system. For more information, get in touch with one of our specialists today.