cpp - Process technology for the chemical industry 02.2018

cpp ACHEMA PUMPS
mixture enters the vacuum pump, the volume
is drastically reduced. Apart from the
condensation effect, this also results in an
increase in the nominal pumping speed.
The operating fluid absorbs the heat of
compression and since liquid ring vacuum
pumps are virtually isothermal, they offer
advantages when pumping temperature
sensitive products such as polymers.
One significant benefit of liquid ring vacuum
pumps is that both the operating fluid
and the materials used for the components
can be adapted to fit the medium being
pumped. Corrosive or explosive gases and
vapours can thus be pumped, too. Due to
the low operating temperatures, pumping
explosive materials can, in any case, be considered
much less problematic than with
other mechanical vacuum pumps.
Construction
A basic distinction is made between single
and two-stage liquid ring vacuum pumps.
Cross-sectional view of a
Dolphin liquid ring vacuum
pump compression chamber
ASK THE EXPERT
NEW SERIES OF DOLPHIN PUMPS
Uli Merkle, Head of Marketing Services,
Busch Dienste
Busch is presenting new series
of Dolphin liquid ring vacuum
pumps at Achema. What
changes have you made?
Both series have been completely
redesigned. Visually, it is
immediately obvious that the
flow channel is now integrated
into the pump housing. This and
the directly flange-mounted
motor make the vacuum pumps
more compact, and a base frame
is no longer required. In addition,
these vacuum pumps are
perfectly suited for installation
or as individual vacuum mod-
ules in vacuum systems. Thanks
to the modular design, it was
possible to considerably reduce
the number of components.
What are the main technical
features of the new vacuum
pumps?
The difference between the two
series lies in the ultimate pressure
that can be achieved, i.e. the
maximum vacuum level. With
the Dolphin LM, the two compression
stages work in parallel
on one shaft. This makes it possible
to achieve an ultimate
pressure of 130 hPa (mbar).
With the Dolphin LT series, the
two compression stages are connected
through the flow channel
so that air, gases or vapours
to be extracted go through them
one after the other. This results
in two-stage compression and
therefore means that an ultimate
pressure of 33 hPa (mbar) can
be reached.
What are the special advantages
of the new series?
In order to prevent corrosion
within the vacuum pumps, stainless
steel impellers are used as
standard, while the standard version
of the housing is made of
cast iron. This material configu -
ration allows for a variety of applications
in processing technology
to be covered. We also offer
stainless steel housing for handling
highly corrosive media. All
sizes are also available in different
Atex versions and temperature
classes. As a result, these
vacuum pumps can be used in
almost all processes in the
chemical and pharmaceutical industry,
as well as in many other
branches. All vacuum pumps
from the Dolphin LM/LT series
are equipped with IE3 standard
motors which guarantee energy-efficient
operation. The optimized
shaft seals contribute to a
significant increase in service
life. Depending on the pumped
medium, Viton and FFKM are
available as material variants.
What will Busch‘s other exhibition
focuses be at this year‘s
Achema?
In addition to the new Dolphin
LM/LT series, we will also be
showing solutions for processes
in which the pumped medium
should not condensate inside
the vacuum pump. For this purpose,
we will be presenting a
dry Cobra NC screw vacuum
pump, one that does not use
operating fluids. These vacuum
pumps achieve a considerably
higher vacuum level compared
to Dolphin liquid ring vacuum
pumps. We will demonstrate the
Cobra NC in a vacuum system in
combination with a vacuum
booster. As individual solutions
for vacuum generation are often
required, particularly in chemical
processing technology. We
will round off our presentation
at Achema with an explosion
shock-proofed R 5 RE rotary
vane vacuum pump. They are
designed to convey explosive
gas/air and vapour/air mixtures.
The Atex-certified vacuum
pumps are suitable for extracting
almost all substances from
explosion group IIB3 as well as
petrol vapours.
56 cpp 02-2018