Plastic pipes of large diameters, even as large as 2,000mm (about 6½ feet), increasingly are replacing concrete and metal pipes for potable and wastewater transport, according to Battenfeld-Cincinnati, McPherson, Kan. Compared to concrete and metal, plastic offers lighter weight, easier installation, zero corrosion and resistance against chemicals and tree roots.
Battenfeld-Cincinnati said that most of the more than 100 large-diameter pipe extrusion lines it has installed so far are for polyolefin processing, the remainder for PVC. The company has produced extrusion lines for insulating PVC in diameters of 800mm (about 2½ feet) and larger. The lines require all of the basic elements of an extruder—barrels, screws, and dies capable of handling large outputs. Battenfeld-Cincinnati lines can handle throughputs of up to 3 tons per hour and produce high-quality pipe in diameters as large as 2,500mm (about 8 feet), the company said. The company has installed extrusion lines for PVC pipes with diameters of up to 1,300mm (about 4½ feet).
With the twinEX extruder models 135, 148 and 173, Battenfeld-Cincinnati offers a wide range of large machines specially geared to gentle processing of PVC. Optimal wall-thickness distribution and excellent pipe attributes are achieved by double spider dies, the company said.
The company has installed large-diameter pipe extrusion lines for polyolefin processing worldwide, primarily in Europe and in the Near East and Middle East. Currently, as many as 10 percent of those lines are intended for pipe diameters over 2,000mm.
Maintaining product quality is a major challenge in creating pipe of such enormous dimensions. High outputs and optimal melt quality are required of the extruders, along with expertise in designing dies. The entire system must achieve optimal wall-thickness distribution and ovality values, and reduce sagging as well. Internal pipe cooling can enhance the energy efficiency of the whole line.
Union Pipes Industry, Abu Dhabi, United Arab Emirates, has a 2,000mm large-diameter pipe extrusion line from Battenfeld-Cincinnati on its production floor. In a Battenfeld-Cincinnati video on YouTube, Mohámed Hageb, general manager of UPI, cites the reasons UPI chose the line: excellent wall-thickness distribution; low ovality; energy efficiency; and the relatively limited overall length of the line itself. With efficient internal pipe cooling, this extrusion line can operate with a shorter cooling section than alternative technologies, saving production space, energy and also materials, thanks to the optimal pipe dimensions. Battenfeld-Cincinnati is exhibiting at NPE in Booth W1810.
Suppliers target polyolefin capabilities
Beier America, Exeter, N.H., is introducing its new high-throughput extruder for polyolefin pipe production. The BRD series of 38:1 L/D grooved feed throat extruders incorporates a variety of features that are new in the Beier machine design.
New features include a feed throat with a large, eccentric feed opening; rectangular grooved feed channels with a large surface area; air-gap heat insulation; and a spiral water-cooling system. The result is high volume material conveying and efficiency regardless of the back pressure, with low water consumption, according to the company.
The barrier screw design includes internal melt channel cooling that improves throughput rates at moderate melt temperatures. The BRD series of pipe extruders is designed for efficient polymer processing at pressures up to 6,600 psi. Beier America's recently developed large-pipe capabilities will be on exhibit at NPE 2015 in Booth S16041.
KraussMaffei Berstorff, Florence, Ky., supplies all extrusion line components for producing polyolefin pipe up to 2500mm in diameter and PVC pipe up to 800mm, including automation components to maximize material savings. The company builds its extrusion lines to produce both standard and complex, nonstandard pipe. Equipment includes conical twin-screw extruders, parallel 32D twin-screw extruders, single-screw extruders and coextruders for integrated extrusion systems in piggyback or tandem configurations. KraussMaffei Berstorff will be exhibiting at NPE in Booth W903.
Merle R. Snyder, senior correspondent
