TK Stainless
TK Stainless
TK Stainless
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
86 MaGaZine high-performance materials<br />
in The heaTinG ConDuCTor LaB<br />
in Werdohl, the new material is put to<br />
the test.<br />
---<br />
sMaLL Wire ConVerTs enerGy inTo heaT<br />
---<br />
Clothes dryers, air conditioning systems, kettles and hair dryers all have one<br />
thing in common: They all need heating conductors to convert electricity from<br />
the wall socket into thermal energy. These conductors are used wherever heat<br />
is required quickly, i.e. without lengthy warm-up times. Though small, they<br />
have to withstand high loads: For example, when a clothes dryer is switched<br />
on, the electricity inside the unit passes through the conductor and heats<br />
it. When the machine is switched off, the conductor cools again to room<br />
temperature – and that makes great demands on the material. Dr. Heike<br />
Hattendorf, project manager at ThyssenKrupp VDM: “In the lab we work with<br />
temperatures up to 1,200 degrees Celsius to accelerate lifetime testing. In later<br />
use, the temperatures are generally lower and so the conductors have a longer<br />
lifetime.” With the newly developed Cronifer 40B, ThyssenKrupp VDM now has<br />
another material in its portfolio which is ideal for use in heating conductors.<br />
The length of time a heating conductor “survives” in an electrical<br />
device depends on the material it is made of, the kind of device and the way<br />
it is used. A good heating conductor material needs to deliver a high lifetime<br />
and high electrical resistivity. That means the material must offer the highest<br />
possible resistance to the flow of electricity through it, forcing the energy<br />
to make more “effort” to get through the wire – the greater the “effort”, the<br />
hotter the wire becomes. At the same time, the material must not melt when<br />
it heats up.<br />
Some applications also call for high shape stability. The US household<br />
appliance industry is a good example. Unlike in Europe, clothes dryers and<br />
air conditioning systems in America use so-called “open heating elements”<br />
consisting of suspended wires which are only supported at a few points. It is<br />
important that these wires do not sag during operation as this could cause a<br />
short circuit.<br />
Heating conductors are manufactured from wire, ribbon or foil<br />
strip and then processed into heating elements. Wires, for example, are coiled<br />
into spirals. However, they should not be confused with the filaments used
Change language