Not all fluid systems are designed to carry the same materials through their pipes all the time. Commonly, in piping systems for materials processing, the system will be required to carry different materials for different process runs. Consequently, it is also common that these lines be purged between process runs. The problem lies in the fact that any recesses or pockets within the lines will trap material, making proper purging difficult or impossible.
The problem of recesses and fluid trapping pockets is especially prevalent with respect to connecting joints, which rely on resilient, elastomeric seals and packings. The typical packed joint was often difficult to assemble and frequently resulted in undesired discontinuities between the connected sections. To meet the high force and rapid disassembly requirements, it has been the practice to use circumferentially extending, multi-section clamping rings. The ring sections have internal and external wedge surfaces that act against each other to drive the joint components axially together. Actuation of the clamp ring is generally accomplished by a thumbscrew that pulls the sections together.