MATERIALS | PVC-O
“All three of these avenues use digital tools to turn
data into information,” he said. “This allows people and organisations to be agile and responsive.” Examples of this include aspects such as
gathering process data from multiple production lines, in order to make future improvements, and using digital tools to design better processes – such as flow control or pipe stretching.
Above: Digital solutions have been used to improve the performance of PVC-O pipe
“Belling in PVC-U pipes is widely applied with both methods, but for PVC-O pipes it is only practical with a mechanical mandrel system,” he said. However, Sica has overcome three main technical
problems to develop a Rieber gasketing method for PVC-O pipe, he said. The problems are: collapse of the gasket; imperfect adhesion of the pipe wall to the gasket; and the inner dimension of the socket (at the gasket) being smaller than the limit allowing smooth insertion of the pipe into the socket. The new method overcomes each problem in a
separate process. The second problem – that of imperfect adhesion – is overcome by using a thermo-controlled hot chamber. “The procedure is applicable to all PVC-O pipes
of different operating pressure classes – and to all PVC-O pipes of different orientation levels,” he said.
Digital solutions Joseph Venegas, of Rollepaal Pipe Extrusion Technology, said that new plastic pipe designs – including those made from PVC-O – can be accelerated through the use of digital solutions. “Structured wall, multi-layer, PVC-O or oriented polyolefin pipes can dramatically reduce the environmental impact of the industry,” he said. “Digital solutions – built around AI and machine learning – offer a key to speed up adoption of material-saving technologies.” He said that digital tools offered three benefits:
n They can turn data from a new process into the information needed to optimise that process – which could come in the form of cloud data systems or AI analytical tools;
n digital tools can offer the user of new technology access to support on demand, when required – speeding up adoption by reducing delays; and,
n digital tools can help companies replicate previous successes across new investments.
24 PIPE & PROFILE EXTRUSION | October 2023
Chamfer improvement One example of using digital technology was given by Guido Quesada of Simulation Driven Engi- neering in Costa Rica. He told delegates that his company has used computer simulation to opti- mise the design of a spigot bevel (or chamfer) for PVC-O pipe joints. “This was in terms of minimising the risk of dislodging the seal, the assembly force and the extent of material removed – while remaining as compliant as possible with standards,” he said. Alternatives to the traditional straight bevel were
proposed – such as applying rounds at the edges, or replacing the entire bevel with a couple of arc segments or with a quarter of an ellipse. Although elastomeric chamfers are commonly used in PVC-O pipe joints, their design is often “less than optimal and even potentially problematic”, he said. A poorly designed or executed bevel can sink its edge on the surface of the seal – wiping off lubricant and increasing axial force – which could dislodge the seal from its best position, he said. The company used finite element analysis (FEA)
to simulate a range of designs and materials. Although no single design was developed, he said that certain rules to help designers to improve their products. For instance, for relatively thick pipe, making the
tip round and the transition as round and as large as possible can reduce risk of the seal being dislodged. However, as pipes become thinner, this approach was not recommended. “It will increase the risk of dislodging the seals, wiping off the lubricant and producing abnormally high assembly force,” he said. If the objective is to achieve the lowest assembly
force with relatively short bevels, an elliptical bevel is more appropriate, he said. “The ideal bevel style may be up to the pipe manufacturer’s circumstances, but there are pointers that can be followed,” he said.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.molecor.com �
www.sica-italy.it �
www.rollepaal.com
www.pipeandprofile.com
IMAGE: MOLECOR
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