In the plastic pipe industry for underground water supply, PVC-U pipes and PE pipes are the main products. PVC-U pipes enjoy a higher strength-MRS is 25MPa, yet the toughness of PVC-U pipes are not as good as PE pipes. However, PE100 pipes enjoy a good toughness, yet the MRS of PE100 pipes is only 10 MPa, which means a lower strength. So researchers and engineers are all the time trying to develop a pipe which enjoys both higher strength and higher toughness properties.
 

PVC-O pipes are the result of the hard works by researchers and engineers.

Biaxally orientation process was originally used in the production of film. In 1972, Petzetakis put this technology into the production of PVC pipes. The biaxially orientation process of Petzetakis is in line process, which means the orientation equipments locate between two haul-off machines.

Later in 1970s, Yorkshire Imperial Plastics in the United Kingdom developed an off line biaxially orientation process, which means the feedstock pipes are produced first, then the feedstock pipes are expanded radially in an off line tooling.
 

Now, after 40 years development, there are two streams of manufacturing equipments for PVC-O pipes: in line tech and off line tech.
 

TaijiBlue^® PVC-O Tech is an in line biaxially orientation technology for PVC-O pipes.