Warp speed for big twin-screw.

The first two giant ZSK-NT tandem twin-screw compounders from Coperion Werner & Pfleiderer (U.S. office in Ramsey, N.J.) are being built now for delivery to a Saudi Arabian PE resin plant. When they start up, the first stage (250 mm screw diam.) is expected to run roughly twice as fast as any previous twin-screw machine of that size--up to 600 rpm.

This huge tandem compounder was developed for output of up to 110,000 lb/hr of bimodal PE, which combines low- and high-molecular-weight polymer chains. The first, high-speed stage melts rapidly, followed by a very slow (100-rpm) second stage (350 mm diam.) for gently homogenizing the difficult material, using less energy and destroying more gels, Coperion says. Tel: [phone] * www.coperion.com

[ILLUSTRATION OMITTED]