TPT March 2015

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Technology News
74 March 2015
Pipe forming with
revolutionary
VSP technology
By Dr Thomas Hohnen, technical sales
tube and pipe plants, SMS Meer
MAXIMUM machine availability,
maintenance-friendly systems, energy
saving, reduced emissions and
lower costs are important purchasing
arguments for operators of steel
and NF metals plants. Optimisation
potentials can be found here in the
hydraulic system. SMS Meer has
further developed a technical solution
for this and, together with the MAE
Maschinen- und Anlagenbau Götzen
GmbH, adapted it for pipe forming. The
variable-speed pump control, or VSP
for short, allows hydraulic systems to
be operated efficiently with pressures of
more than 450 bar.
The general principle of the VSP
drive: the oil pressure is generated
only when it is demanded
by the system – in other
words, only when it is really
required. Commercially
available axial piston
pumps are employed,
controlled via the speed of
the servo motors. The control system’s
intelligence now lies in the electrics
and no longer in the hydraulics. The
pressure is built up without the use
of proportional valve technology; the
throttling of the hydraulic power with
the associated heating of the oil typical
of conventional systems is eliminated
completely. This enables an extremely
energy-saving and low-loss hydraulic
system to be built – not only for “small”
systems, but also for high press forces
and for systems with several hydraulic
axes.
The system gene-
rates only the oil
pressure that is actually
required. The motors
run only during the main
function of the machine,
eg during the forming
process, and are
otherwise at standstill.
This means less power
consumption and less
noise. The design
even permits energy
to be fed back into the
mains, for example
from the compression
energy of the oil. Since
its introduction in the
large-diameter pipe
sector, the principle
of the VSP drive has
proved its effectiveness
in two GCP® gap closing
presses. The customers
Izhorsky Trubny Zavod
(ITZ) from Kolpino near
St Petersburg and JSC
Vyksa, Vyksa, both
Russia, employ their
new 25 MN GCP® gap
closing presses from
SMS Meer for the cost-
effective production of
pipes with small diameters and large
wall thicknesses. The VSP drives have
proven themselves on both gap closing
presses in the production of offshore
pipes for pipelines. During the forming
process, gap closing presses are used
after heavy plates have been quickly and
precisely formed on a JCO® pipe forming
press. The gap closing press reduces the
remaining gap between the plate edges
to a minimum – one of the preconditions
for a reliable tack welding process. The
use of the variable-speed pump control
allowed the energy consumption to be
reduced by 50 per cent compared with
the conventional hydraulics. These gap
closing presses satisfy the preconditions
for the “ecoplants” label – the hallmark
for sustainable technologies from SMS.
Following the successful use of the
VSP drives in the gap closing presses,
SMS Meer is now using this technology
in all presses for large-diameter pipe
forming. For the customer Corinth
Pipeworks, Corinth, Greece, not only a
gap closing press but also a crimping
press is currently being equipped with
the VSP drive. In order to guarantee
an assured and tested quality of
the innovative hydraulic concept for
Corinth Pipe, the crimping press was
assembled and tested in SMS Meer’s
own workshops.
The energy consumption of
the crimping press is reduced by
approximately 60 per cent compared
with earlier product generations. This
saving is essentially made possible by
the feedback of the electrical energy into
the grid, the switching off of the pumps
at no-load and by the fact that no cooling
system is required.
Thanks to the experience gained with
the gap closing press, commissioning
of the VSP drives on the crimping press
went very smoothly. The complete
control software comes from SMS Meer.
“Sturdy” differential pump system installed in the crimping press
The gap closing press requires 50 per cent less energy than
the older machine generations thanks to the variable speed
pump control (VSP)
Use of the VSP drives in all pipe forming presses. Here:
successful test run of the crimping press with VSP at the
SMS Meer workshops in Monchengladbach, Germany