FastROOT - Kemppi

8
CASE
Kemppi ProNews 2 • 2006
Jukka Pohjola, Technical Editor
Vaahto Oy acquires
FastROOT
The large spiral heat exchangers manufactured
by Vaahto Oy of Hollola, which is
part of the Vaahto Group, can have welding
seams hundreds of metres long. Almost
all the welds are pressure-bearing,
so the work requires great precision both
from the welder and the welding equipment.
Vaahto Oy has acquired Kemppi’s FastMig equipment
with FastRoot installed, for the purpose of speeding
up welding work and facilitating the uniformity of the
welds.
Metal plate up to 2 metres wide unrolls from the roller
onto the line, and then spacer studs are automatically
stud-welded to the plate. The purpose of these is to keep
the spirally-rotated metal plates separate, so that there is
a channel between the plates for medium fl ow distribution.
This is how the large spiral heat exchanger starts to
take shape at Vaahto Oy’s Hollola plant, for delivery to
the pharmaceutical industry in the USA.
Vaahto Oy is a worldwide manufacturer of equipment
for the paper and process industries. The spiral heat exchangers
produced at the Hollola factory are used all
over the world in such industries as pharmaceuticals, oil
refi ning, paper, and paints and pigments.
Spiral heat exchangers are more easily cleaned and less
prone to fouling than tube heat exchangers. Furthermore,
they offer greater heat transfer effi ciency in relation
to their size.
Weld quality an important factor in the
production process
Workshop manager, Sami Ketola, who is in charge of
the manufacture of heat exchangers, says that the manufacture
of just one heat exchanger requires hundreds of
metres of welds, so their quality and the productivity of
the welding work are essential elements in the production
of spiral heat exchangers.
Almost all welds are pressure-bearing, which sets particularly
demanding requirements both for the welder and
the welding equipment. Spatter is not allowed and each
weld is checked at least visually, but usually also with
penetration fl uid or by some other NDT methods.
When spacer studs are attached to the metal plate, the
plate is rolled into a large spiral, and the ends of the roll
are closed with welds. With special metal qualities, this
work stage might last weeks or even a month. ”There
the shield gas fl ows and the arc burns for a long time,”
explains Mr Ketola.
It is for the speeding up of such time-consuming work
stages that Vaahto Oy has acquired Kemppi’s FastMig
welding equipment with FastROOT process, for
speeding up root pass welding.
”We intend to replace mainly TIG welding with
FastROOT, and thus increase the productivity of welding
work and of course also to increase the uniformity of
welds,” says Mr Ketola.
Vaahto Oy already has long experience of Kemppi’s
welding equipment. Confi dence in the operation of the
equipment has increased with the years of experience,
and, at least on the basis of the early stage, FastROOT
seems to meet the set targets very well. n