Pigs are snug-fitting plugs which are able to perform various maintenance tasks such as cleaning or removing deposits or blockages in pipe and pipeline systems from the inside. A gaseous or liquid propellant is used to push the pig through the system. This strategy avoids rinsing loss of valuable product, provides reduction of adverse environmental impacts, and gains high efficiency for less investment. The book describes clearly and methodically the important basic equipment required for the planning and design of pigging units. Many practical examples are shown for the operation of industrial pigging units, drawn from the authors' longtime experience in this technology. In this form and scope the book is an unrivaled presentation of this technology. Engineers and chemists who plan, construct, operate and maintain production plants in the chemical, food, cosmetics, pharmaceutical and petrochemical industry will find an invaluable source of advice and reference for pigging units.