EoW July 2010

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EuroWire – July 2010 28
technology news
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:
World’s largest reeling cable order for cranes
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
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:
Website:
Rosendahl's patented clenching concept for dry cable production ▲ ▲
Tratosflex-ESDB cable will be in use at Korea’s Busan Port ▲ ▲