EoW July 2010

technology news

World’s largest reeling cable order for cranes

Cable manufacturer and supplier Tratos Ltd has won what is believed to be the largest order in the world for reeling cable for high-speed cranes. The Tratosflex-ESDB cable is to be used in 38 ZPMC cranes at the latest Busan Port terminal in Korea. Busan Port is the world’s fifth busiest container port and largest trans-shipment port in North East Asia. Equipment in use at the port includes the latest generation high-speed container cranes, which operate at speeds up to 300m per minute. Tratosflex-ESDB has been designed to combat the common problem of twisting that affects cables reeling at high speeds. Twisting makes cable cores elongate unevenly so conductors on the outer layer of a strand are at greater risk of damage. A broken cable reeling at high speed is dangerous, and can cause extensive and costly damage to equipment. Tratosflex-ESDB is different from other reeling cables available in that Tratos engineers have modified the internal cable design, tightening the structure against the internal relative movement to accommodate high-speed applications. A medium-voltage rubber insulated and sheathed drum reeling cable, Tratosflex-ESDB operates in temperatures from –20ºC to +60ºC. Tratos Ltd – UK Fax : +44 1246 858001 Website : www.tratos.co.uk

Tratosflex-ESDB cable will be in use at Korea’s Busan Port ▲ ▲

Dry cable offers advantages Totally dry cable designs are said to offer benefits in terms of cable preparation time and fibre-splicing costs. In conventional cable designs a gel is used to achieve water tightness. In dry tube cable designs, the gel is replaced by swelling materials such as super absorbent powders (SAP).

An important process parameter in the buffering process is to control the excess fibre length (EFL). Replacing filling gels with super absorbent powder results in EFL increase. The invention of the so-called clenching process within the newest generation of high-speed loose tube secondary coating line RL-R/OFC40 buffering lines support a precise EFL control, even on small dimension products. The clenching concept compensates the EFL increase, since low EFL is required for the production of compact, dry loose tube fibre optic cable (FOC) designs. A clenching caterpillar, installed in front of the mid-span capstan inside the tube cooling section, ensures a very low tube tension during the tube crystallisation process. This also results in less post shrinkage (REL) of the produced buffered tube. The clenching caterpillar NCA 210 has to meet specific demands of long-term stability within a challenging environment. Recent design improvements ensure a long-term reliability of the production process. The clenching caterpillar NCA 210 is also suitable for the upgrade of existing Nextrom OFC40 and Rosendahl RL-R buffering lines. The production of loose tubes without jelly filling can cause tube diameter variations and collapsing of the tube after the extrusion head. In order to obtain a uniform tube dimension the diameter of the tube is controlled by the injection of pressurised gas into the tube. To avoid friction between optical fibres and

Rosendahl's patented clenching concept for dry cable production ▲ ▲

the plastic tube, a tube lubricant can be added. Water tightness of the tube is achieved by using super absorbent powders as swellable powder or in yarn form. The key characteristics of the patented clenching concept are: Integrated EFL process control system for both jelly-filled • and dry buffered tubes Tube diameter control system • Specific clenching caterpillar design to cover demanding • surrounding conditions Modular concept also suitable for the upgrade of existing • buffering lines Rosendahl Maschinen GmbH – Austria Fax : +43 3113 5100 59

Email : office@rosendahlaustria.com Website : www.rosendahlaustria.com

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EuroWire – July 2010