PT27- 28/3
2 PORT TECHNOLOGY INTERNATIONAL www.porttechnology.org
DRY BULK AND SPECIALIST CARGO HANDLING PRODUCT PROFILEPRODUCT
PROFILE
The Garant Feed Mills group, who since 1999, have had extensive
experience working with a Flexiport unloader at their mill in
Pöchlarn, Austria, on the Danube River, decided to install the same
unloader type at another of their mills; in Aschach, Austria. The
new Flexiport, which has been incorporated with the latest
technical developments, was delivered to Aschach, also on the
Danube, and installed at the beginning of 2005 (see Figure 1).
The new unloader replaced an older system which used a cutting
head nozzle (Figure 1). The old nozzle, like many other similar
systems, made large holes, but was not very effective in handling
non-free flowing materials.
New featuresThe new unloader reduces unloading time in half and
is equipped with effective sound insulation and dust suppression.
This was one of the main requirements of the client in respect to
the unloaders environmental influence, especially as the mill’s
location is in close proximity to a very touristy area near a
famous cycling path along the Danube. A further interesting aspect
of the new installation is its new drive control, which uses FI
frequency inverters.
The pneumatic system has two turbo blowers, each 110 kW. They
are started and controlled via frequency inverters; the system is
also able to work with one blower, achieving a capacity of approx.
50 per cent. The blowers, the hydraulic package, and the electric
panels are separated inside a machinery house in container form.
The electric and hydraulic settings are set by the manufacturer,
facilitating the site assembly.
Instead of a cutting nozzle, the Flexiport uses a rotating
feeder (Figure 3) that is moved against the material. A swivel and
kick in arrangement at the nozzle makes it possible to reach
material inside the hatch and under the hatch wings. This is very
beneficial when unloading older ship types that have inside
reinforcements. The nozzle also has a remote adjustable nozzle air
entrance, which allows one to get the best air to product
ratio.
Normally, only a short boom is needed for unloading ships
between 400 and 1,500 dwt. In this particular situation, a 20m
trellis work boom was designed to overcome the distance between the
ships (tied to a floating pontoon) and the unloader itself mounted
on top of an existing conveyor bridge, which had previously carried
the old unloading system (Figure 2). The structure was reinforced
and optimised. For smooth operation, the drives of the winches and
slewing have a speed control, with a start and stop ramp.
Controlling air flowThe traditional way of controlling air flow
on turbo blowers is by using a butterfly valve (throttle valve). It
reduces the load at the motors together with a second mechanically
operating flap valve (Figure 4) that changes the position of the
flap according to the air pressure (air speed) in the conveying
system. With this simple system, it is possible to set a certain
required air speed, but it is limited to one setting at a time.
This is done by adjusting the counterweight of the valve.
This control method is used in small pneumatic mobile conveyors
(GSD) and has been traditionally used in ship unloaders.
New developments in continuous ship unloading (CSU)New drive
control applications in pneumatic ship unloading: The use of
frequency invertersTomas Kisslinger, NEUERO Industrietechnik, GmbH,
Melle, Germany
Figure 2. The older system used a cutting head nozzle.
Figure 3. The Flexiport uses a rotating feeder.
Figure 1. A 20m trellis work boom was designed to overcome the
distance between the ships.
PRODUCT PROFILEPRODUCT PROFILEPT27- 28/3
PORT TECHNOLOGY INTERNATIONAL 3
PRODUCT PROFILEPRODUCT PROFILE
The use of programmable logic control (PLC) has opened the way
for new control methods.
The second method of regulating air flow is by using a frequency
inverter (FI) and control software on the PLC. One flap (Figure 5)
does the work of both, like the traditional mechanical variation.
The air flow regulator can be set at different points using the
motor current. This makes the system more flexible (compared with
the traditional mechanical system) to operate the unloading system
for different goods, and saves space and energy because only one
valve is used in the air flow. It is not as flexible as the speed
control of the blowers though, as described in the third method of
control below.
The third method, successfully applied, is to directly control
the blower drives using the FI technology. With this method,
startup can be programmed with no valve (Figure 6) at all in
the
pneumatic line, and is only limited by the motor current. The
main advantages of this system are:
• Less energy consumption
• Flow control at any unloading situation – partial load
• Capacity settings for different products, such as wheat or sun
flower seeds
The energy is saved because the blowers do not run at full speed
all of the time, but rather at a lower speed during idle operation,
as well as during partial load operation. This is especially useful
for systems handling different types of materials or when needing
to maintain the same capacity during different operation
situations, therefore avoiding big fluctuations in the material
flow. Operation is quite simple: The settings can be adjusted from
the operator’s touch panel, as shown in Figure 7.
ResultsThis system was introduced on the Flexiport unloader (for
non- free flowing materials) at Garant Feed Mills in Aschach. The
tests were successful and the client was especially satisfied with
the solution of flow control, because his existing conveyors and
scales could not handle lighter products at higher capacity rates.
The new settings allow continuous work, while reducing downtime
caused by overflowing conveyors or scales.
The air flow control in connection with the PLC and the use of
FI in pneumatic conveying system, especially in ship unloading,
offers a wide range of controlling methods in relation to the air
speed in the system and to the unloading rate.
With prices coming down, using FIs at the main drives to control
air is becoming an attractive option, as it is making ship
unloading equipment more flexible, and is reducing overall
operating costs.
DRYBULK AND SPECIALST CARGO HANDLING
Tomas Kisslinger has twenty years experience in
bulk handling, especially in grain related areas. Since
1992, he has been Managing Director of NEUERO
Industrietechnik.
NEUERO is manufacturer of mobile pneumatic
conveyors, grain vacs and ship unloader/loaders for
transport of bulk materials such as bulk grain, meals,
plastics and alumina.
NEUERO started in pneumatic grain conveying over 80
years ago with the manufacture of small agricultural
machines. Since then the company has delivered
equipment in the 20 t/h to 2000 t/h range to many
installations around the world. NEUERO has two
companies with sales, engineering, manufacturing and
service facilities in Germany and in the US.
Tomas Kisslinger
NEUERO Industrietechnik
Neuerostr. 1
49324 Melle
Germany
Tel: +49 5422 9503 20
Fax: +49 5422 9503 50
E-mail: [email protected]
Web site: www.neuero.de
ABOUT THE AUTHOR ABOUT THE COMPANY ENQUIRIES
Figure 4. Mechanical system with starting valve below and air
flow regulator.
Figure 5. FI valve below and vacuum breaker. Figure 6. FI drive
with vacuum breaker (no air flow regulator).
Figure 7. Touch panel blower speed settings.
