20
Cooling dress for hot days
Heat exchangers for Wendelstein 7-X pipes
The technical challenge faced by the mechanical engineering
company was the combination of high power input, tight tolerances
and the use in ultra-high vacuum. The cooling system is
designed for a power input of 50 to 100 kW/m2 and functions as
a heat exchanger: cold water flows in four millimeter-thin tubes,
which in turn are located in eight millimeter-thick tubes. The
return flow then takes place in the space between the two pipes.
This design allows manufacture of differently shaped port liners
– round, rectangular or oval – that fit precisely into the narrow
installation spaces of 15 to 20 millimeters.
Wendelstein 7-X is progressing towards completion.
All elements that come into thermal contact with
the plasma will be actively cooled with water in the
future. This also includes the ports, which connect the plasma
vessel with the outer vessel and serve to observe and supply
the plasma. To prevent the ports from inadmissible heating
due to thermal radiation from the plasma, and with them the
cryogenic chamber, they must be protected with water-cooled
liners. These 86 „port liners“ are developed and manufactured
by NTG Neue Technologien GmbH & Co. KG.
SMALL AND MEDIUM-
SIZED ENTERPRISES
NTG Neue Technologien GmbH & Co. KG,
Gelnhausen, Germany
“The order has allowed us to expand our vertical range of manufacturing capabilities,”
says NTG Neue Technologien GmbH & Co. KG. More than 10,000 four- and eightmillimeter
tubes were cut to length for each of the port liners and their ends prepared
for welding. The company set up a lathe workstation and operated it partly in three
shifts. To weld the end caps to the eight-millimeter pipes, it purchased an orbital welder
and trained its employees accordingly. The ring manifolds, which distributes the water
to the individual pipes, and other components of the port liner are machined from sheet
metal. For this purpose, NTG purchased a waterjet cutting machine and integrated
it into the manufacturing process. The company installed various measuring devices
for the extensive testing of the port liners, e.g. to detect leaks at 160 degrees Celsius
and 25 bar in the port liner. NTG: “We also benefit from these enhancements for other
orders. We now have the opportunity to use the developed technology elsewhere.”
Water-cooled port liners
Photos: NTG Neue Technologien GmbH & Co. KG