EuroWire July 2015

34 / 80

News
Technology
July 2015 32
Hradil Spezialkabel, based in
Bietigheim, Germany, presents a flexible
5,000V power supply cable for maritime
applications at temperatures as low as
-200°C. The cable is typically used on
LNG carriers. What makes this cable so
special is that, instead of copper strands,
it contains strands made from pure nickel.
Thanks to this new low-temperature
cable, disruptions to operations caused by
frequent cable malfunctions are reduced
to a minimum. The cable is available in
diameters from 6mm2 to 185mm2 and, on
request, can be delivered with UL/CSA
certification. For some time, attention has
been turning to alternative, previously
uneconomical, transportation options
in response to the growing demand for
natural gas and high gas prices. One such
option is transporting liquefied natural
gas by carrier.
Here, natural gas is cooled down to
its boiling point at -161.5°C. At this
temperature – and at a normal ambient
pressure – natural gas changes to its
liquid state, reducing its volume by a
factor of 600. This would allow one cubic
metre of natural gas to be transported in
a piece of hand luggage, eg in a 1.5 litre
thermos bottle.
Liquefied natural gas is a non-toxic,
limpid and odourless fluid. After being
temporarily stored in cold boxes at the
port of destination, eg Rotterdam, it is
returned to a gaseous state by increasing
its temperature as and when required –
allowing it to be transported by pipeline
again.
A pump and power supply cable must be
lowered into the icy storage tanks before
liquefied natural gas can be pumped in
or out. The cable in particular has often
been identified as a weak point in this
process. Cable malfunctions have been
a regular occurrence – not only because
cables have to be able to withstand
bitterly cold temperatures as low as
-200°C, but also because mechanical
loads are significant, as the cable and
the pump need to be lowered more than
40 metres below the surface into gas
storage tanks. The harsh environmental
conditions of the open sea, with
permanent UV radiation and saline
humidity, place an additional burden on
the cable. To overcome these challenges,
Hradil engineers have developed a
special cable with steel armouring for
this type of maritime application. Hradil’s
low-temperature cable is available in
diameters from 6mm2 to 185mm2. The
steel armouring offers vital protection
against high mechanical loads, but
means that the cable can no longer be
manufactured in a conventional cable
extrusion process.
This is why Hradil Spezialkabel has
developed a special manufacturing
process that creates multi-layered PTFE
(polytetrafluoroethylene) film. PTFE
is also known under its trade name
Teflon® produced by DuPont®. The new
low-temperature cable is available in
different lengths depending on customer
requirements, completely preassembled,
and is delivered with certified connectors.
Hradil Spezialkabel – Germany
Website:
Beating temperatures as low as -200ºC
▲ ▲ Hradil power supply cable for maritime applications
at temperatures as low as -200°C