The new high melt strength PE100 grade from Qenos, Alkadyne HDF145B, allows extrusion of pipe with diameters well beyond 1,000 mm and with wall thicknesses of 100 mm plus.
Wall thickness for PE100 pipes used in directional drilling projects is a critical parameter for designers when considering both end use and installation. As well as considering use performance, designers must take into account both the abuse resistance and tensile strength of the pipe when determining installation performance and deciding on the suitable SDR rating and wall thickness. Directional drilling projects that require long pipe strings need pipe with thick walls to withstand the high tensile forces experienced during installation.
Qenos Alkadyne PE100 grade HDF145B allows extrusion of pipe with wall thicknesses well beyond traditional capabilities. Examples of pipe made using this grade are 1,200 mm diameter, 120 mm wall thickness pipe for an under river HDD project; and a 500 mm, 74 mm wall thickness pipe for an underground island crossing.
“Alkadyne HDF145B has ultra-low sag during extrusion, enabling the production of pipes of diameter above 1,000 mm and with wall thicknesses beyond 100 mm,” said Qenos Product Development Executive Dr Predrag Micic.
“This enables pipe design of dimensions and tolerances able to withstand far higher operating pressures than previously possible.
“Large pipe HDD projects can also benefit from the increased wall thickness, with high tensile strength enabling long pipe strings to withstand the pulling forces employed during installation.”
The ultra-low sag of HDF145B is related to its melt strength performance, which is illustrated in Figure 1.
The superior melt strength also improves pipe dimensional stability, allowing the pipe to be manufactured within tighter tolerances – enabling real savings in raw material usage while providing ease of welding, which is one of the key advantages of PE pipes.