EoW July 2013

News Technology

Seamless aluminium sheathing of high voltage cables

With six lines now in production, BWE’s SheathEx™ process is becoming the new alternative to seamless aluminium sheathing of high voltage cables. A further line will be installed and commissioned in Europe during the second quarter of this year. The SheathEx process is an extension of the well established Conform™ and Conklad™ continuous extrusion technology. The SheathEx machine extrudes a continuous and seamless aluminium tube from two 12mm diameter rods around a high voltage cable core. BWE collaborated with high voltage power cable producers in China to develop the product and process specifications for this new and unique technology. The SheathEx machine incorporates a large crosshead to accommodate the large diameter dies required for cable sheathing. The aluminium sheath is seamless, with no weld line or bead. The twin groove mode of operation ensures the aluminium sheath is concentric. heating system provides a very even temperature distribution around the tooling, leading to very stable running conditions, and consistent properties in the aluminium tube. The feedstock material is standard CCR aluminium rod, which is readily available and cheap, compared to other materials (such as flat aluminium sheets used in a welding line). BWE’s patented induction

▲ ▲ A BWE SheathEx production line

The cable core passes continuously through the crosshead. A cooled insertion tube protects the cable core on entry to the crosshead, and rapid quench of the aluminium tube immediately after the die, prevents thermal damage to the core. Downstream from the SheathEx machine the cable sheath is corrugated in-line and coiled onto large drums. The SheathEx process is a continuous (no stop marks), reliable (no weld) and cost effective (cheap materials, low energy etc) method of sheathing high voltage power cables. SheathEx, Conform and Conklad are registered trade marks of BWE Ltd. International patents have been filed for the SheathEx process, SheathEx tooling system, machine arrangement, control method and induction heating technology that is employed. BWE Ltd – UK Website : www.bwe.co.uk

Matt TPU for wire and cable Huntsman Polyurethanes has developed a non-blooming, matt, polyester-based solution for the wire and cable market. Irogran® A 85 C 5024 DP is a new material to eliminate the risk of blooming (when additives migrate to the surface of a material and become visible). Blooming has no effect on the mechanical performance of cable, but it is unsightly and is an issue that cable manufacturers have looked to resolve. Irogran A 85 C 5024 DP is a halogen-free TPU that offers a consistent matt finish and stable extrusion qualities. Easy to process, the product is thought well suited to wire and cable applications such as jacketing, spiral and data cables. A number of customers have already trialled the product, which has passed third party RoHS and halogen-free tests. The compound is targeted for use in China, but the company anticipates interest from elsewhere. Henry Yao, market development manager for greater China at Huntsman Polyurethanes, said: “Irogran A 85 C 5024 DP is an important addition to our wire and cable portfolio. There are other matt technologies available on the market, but this is unique in terms of the formulation and its non-blooming properties.”

Huntsman Polyurethanes – USA Website : www.huntsman.com

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July 2013