Pigging technology has developed considerably over the last twenty years. Pigging processes have been optimised thanks to a wider range of equipment and services, the development of standards for piggable pipework and fittings and the establishment of a forum for pigging technology.
Level of pig technology
Two pig systems are used in many batch processing plants and work as follows: The first pig is propelled by the pumped product to the specified destination. The second pig can then be propelled through the line, in order to recover all product residue from the pipeline, or alternatively the residue product can be returned back to the source tank by propelling the first pig back to the "home position". Thus, a two pig system is the optimum solution where bi-directional product distribution is required. Where bi-directional product distribution is not required a simpler one pig process can be adopted. In fact, the development of our new T40 tee port valve even allows the use of one-pig systems for applications with multiple product destinations. The T40 T-port valve therefore, combines the simplicity of a one pig system with the operational flexibility of a two pig system.