Description
The Ductile Iron Coupling is a connection fitting obtained by an annealing, threading process of malleable cast iron, used to connect one or several castings, ductile iron and PVC pipes. It is cheaper than universal flange adapters or couplings, allows for fast, leak-free and reliable connections, facilitates the removal of valves and fittings without disturbing the pipeline, and accommodates limited pipeline movement, expansion, contraction and angular misalignment.
http://www.jianzhi-fittings.ne....t/grooved-iron-pipe-