Major equipment manufacturer Buhler is very active in the
production of pneumatic bulk handling equipment, as well as
mechanical products. Its range includes unloaders (both
pneumatic and mechanical), continuous shiploaders, worldleading
grain storage solutions (silos and flat storage), as well as
conveying components for grain-related industries.
Pneumatic equipment is particularly popular for handling
some types of dry cargo, with its soft handling properties and
high throughputs.
In the ship unloading business, however, pneumatic equipment
— specifically pneumatic unloaders — cannot be considered to
have soft handling properties and high throughputs. In contrast,
conveying speed in pneumatic solutions is much higher than for
example with mechanical unloaders, therefore mechanical
solutions have a clear advantage. Soft material conveying is one
major advantage of mechanical solutions compared with
pneumatic solutions.
High throughputs are also clearly the province of mechanical
ship unloaders compared with pneumatic ship unloaders. Energy
consumption, availability and durability of the mechanical
solutions are superior.
Buhler’s equipment is used to handle all dry agribulk
commodities, from grain to soya, rice to maize. It is also used
with mealy products, oilseeds, pellets and derivatives. Its ship
unloaders handle all the products used in the industries of
Buhler’s Grain Processing business units (grain milling, feed,
biomass, sortex, rice and malting).
Compared with other pneumatic unloaders on the market,
Buhler’s pneumatic unloader uses a rotary blower instead of a
multistage fan or double fan. Roots blowers are extremely
robust and, due to their low speed, have a long life. Generally
multistage blowers need to be replaced much sooner, are very
sensitive to rest particles and have high power consumption
during resting. Also with the air lock, Buhler went the extra mile
to fight wear and tear. It has an overload protection, with
automatic change of rotation direction when blocked, doubling
its life time. Furthermore, the Buhler solution has exchangeable
wear plates. Some other solutions only have a one-way
direction air lock and no exchangeable wear plates. The Buhler
suction pipe ‘elbow’ is round-shaped, with no change in diameter
over the elbow. Some competitors use square elbows, which
increases pressure loss and turbulence, and this results in more
wear. Another nice feature of the Buhler solution is the large
size wheels and big clearance to the ground, which makes
manoeuvring very easy even when travelling over obstacles such
as rails.

Contamination — sanitation
Pneumatics are reputed to have better sanitation as no material
remains in the piping. This is not the whole truth as, for
example, Buhler has optimized its chain conveyors to also ensure
no material will remain in the conveyor. Buhler chain conveyors
are optimized to have no ‘dead’ zones and therefore fulfil similar
sanitation requirements to pneumatic systems.
A mechanical unloader can reach not only under the deck rim,
due to its kick-in/kick-out function, but it also does not lose
capacity because its geometry is always the same, consequently
performance is always the same. The pneumatic solutions
however do have a smaller working area and lose capacity
dramatically the moment the suction pipes are extended. In
other words pneumatic unloaders reach full capacity only, if at all,
at a very limited time during the full unloading process. i.e. if
there is a low tide at the start of an unloading process, it may
already require the extension of the suction pipe, in such a case
the pneumatic solution never reaches full capacity.
Looking at unloading in three phases, the mechanical unloader
can run at full capacity during phase one with automatic sink-in
feature, during phase two with kick-in and kick-out. Only during
rest-unloading does the throughput decrease. The pneumatic
system can not even run full capacity during phase one due to
the required extension of the suction pipe.
Rest-unloading (phase three of unloading)
Pneumatic systems do have an advantage during final clean up, as
they kind of work like a vacuum cleaner. Still, throughput during
this final clean up is drastically below maximum capacity. In fact,
most customers do use the help of front-end loaders during final
clean-up even when unloading with pneumatic systems. For
mechanical unloaders, the use of these loaders is standard
Another advantage of the mechanical unloader is its stronger
hoist, it can bring loaders up to a weight of 15 tonnes into the
ships hatch; the pneumatic unloader would require a separate
crane for this task.
Maintenance and repair
Pneumatic solutions have more parts affected by wear and tear,
telescopic pipes, bends, air lock, filters and similar. Furthermore
conveying speeds are much higher in pneumatic solutions, again
resulting in more wear and tear.

*applicable for Buhler market segments only – may differ for other segments)
Pneumatic expertise integral part of handling systems for power plant
Alternative and renewable sources of energy are a major
concern not only due to limited fossil fuel resources, but also
within the context of the worldwide efforts to limit gas
emissions, writes Alain de Visscher, commercial director of VIGAN
Engineering SA. New power plants as well as some existing
energy producers are upgrading their existing technologies with
latest innovations, in order to fulfill their legal obligations of
protecting the environment while containing costs.
The French group Suez is a major player in Europe and
worldwide, with about 200,000 workers and an annual turnover
of more than US $110 billion. Suez has integrated this approach
for many years, with very significant investment in engineering
developments and state-of-the art industrial installations.
Electrabel, the electricity division of the group, developed a
special project during the last few years for its power plant in
Gelderland (Nijmegen, The Netherlands) of a capacity of about
600MW. Tractebel, its Belgian engineering affiliate was in charge
of developing this co-firing project (biomass and coal), by
increasing the incorporation of wood pellets by about ten times
(from 8tph [tonnes per hour] to 75tph), up to a rate of 20% of
the total energy produced by this upgraded plant. Since its
operational start in 2010, this Electrabel power plant has
become one of the world’s largest co-firing plants with wood
This co-firing process allows Electrabel to benefit from a
large number of ‘green certificates’. This system of green
certificates is a European mechanism. The promotion of
investment in green renewable energy (for example, windmills or
biomass power plants) is balanced on the other hand with the
obligation for fossil fuel plants to buy those green certificates.
Geldof, a leading supplier of industrial components and
turnkey-projects, based in western Belgium, was selected by
Electrabel as turnkey contractor for this process transformation,
including new installations for the reception and the storage of
the estimated 550,000 tonnes per year of wood pellets required
by the power plant.
Wood pellets are transported to Electrabel plant by barges
from various origins, thanks to the excellent hinterland river and
canal system in the Netherlands for bulk transport.
Nevertheless, the discharge of such volume for a key sector
requesting 24-hours-a-day reliability requires the highest-quality
and the most efficient operational performances.
VIGAN Engineering S.A., also a Belgian company, was selected
to manufacture and to install the pneumatic unloader for the
barges of wood pellets. The company specializes in pneumatic
and mechanical ship-unloaders mainly for agri-bulk cargoes, with
40 years of experience and more than 1,150 pieces of
equipment deployed around the world.
The challenge of transporting any wood residue is usually
dealing with the low density of these materials. Therefore the
most common process is pelletizing, in order to condense them
into granules (usually about 10–15mm length and 5–6mm in
Thanks to this process and a reasonable content of humidity,
the wood pellets are quite free flowing, which allows them to be
easily conveyed from the production facility up to their use as an
input in the power co-firing with coal.
While being transported to the plant, these pellets can easily
break up, with dust being emitted. It is not convenient to use
grabs due to several factors, such as important mechanical
efforts of quay structure, dust escaping into the environment,
eventual spillage that can be difficult and costly to clean up, and,
of course, a low ‘through the ship’ efficiency when unloading
small barges.
Pneumatic unloaders, however, are recognized as a more
convenient solution for unloading barges, compared to grabs or
mechanical unloaders:
* higher unloading rate mainly during the cleaning of the hold
with the intake nozzle being able to suck down to the latest
product particle on the hold floor but also to reach the hidden
* safety: one operator is able to manage the whole unloading
operation, not only thanks to a remote control for all major
displacements of the suction nozzle into the hold, but also as the
driver of an auxiliary skid steer loader, for speeding up the final
cleaning even further.
*  environment: No dust is emitted, as the whole unloading
system is under negative pressure and/or totally enclosed.
* no spillage and need to clean the surrounding quay.
* minimum breakage by optimizing the air and product speed in
the pipes.
*  low-weight equipment with far fewer mechanical efforts on
the quay structure.
For achieving these objectives, VIGAN’s NIV 600 model in
Gelderland has the latest technologies available, such as the
following as a few examples:
* three turbo-blower groups (for each four stages) with
direct drive, controlled by the latest speed variators
(frequency inverters) by Schneider Electric.
The direct drive is a major improvement because it reduces
not only the numbers of bearings on a traditional drive with
belts, but also the mechanical efforts on the turbine shaft.
The multi-stage turbo-blowers maximize the suction
capabilities for a larger range of product characteristics, and
allow material to be handled without needing any special feeding
device. Working in combination with the speed control system,
it allows the energy consumption to be optimized
precisely. Some VIGAN customers reported figures as
low as 0.6 to 0.7kWh/tonne, thanks to these
technology developments and those chosen by
As also observed in this project, these three turboblower
groups give the customer a convenient extra
reserve of suction power capacity, to face any
unexpected event and to guarantee the daily unloading
* air jet pulse system for automatic cleaning of
the filter.
Widely recognized among the food and feed
industry sectors for the global best performances and
reliability, this system offers also a major advantage
about safety: no running mechanical parts are in contact
with the air flow which could be eventually
contaminated with dust and therefore could be the
origin of explosion.
* major reliability thanks to special alloys that protect
against wear, used in the elbow between the vertical and
horizontal suction pipes, in the airlock components.
* major safety assurance from the integration of
compulsory rules on European engineering design norms,
equipment manufacture and human resource protection. The use
of alternative sources of energy such as biomass will certainly
increase during the coming years and all the logistic aspects of
these inputs require very careful approach. Electrabel receives
full credit for this landmark project in green electricity
production. It also receives the credit for having understood the
benefits of the pneumatic technology for a reliable and efficient
In other news, VIGAN has confirmed that, at the beginning of the
year, it signed a contract with the Sociedad Portuaria de Santa
Marta in Colombia, to supply a 600tph NIV 600 pneumatic ship
unloader. This unit will be delivered in early 2011.
In January this year, a new 750tph SIMPORTER ship unloader
was delivered to Ulsan port in South Korea. This unit will work
alongside an older VIGAN machine; both can be seen in the
picture below, with the new model on the right.
Noise is an increasingly important issue for customers, mostly
driven by local rules and regulations. On average, in Buhler’s
experience, pneumatic solutions have about 10dB higher noise
level than mechanical systems.
Buhler’s unloader product range includes:
The Portanova. This is a pneumatic ship unloader, designed for
efficient unloading of grain and oilseeds.
The unloading throughputs vary from 250tph (tonnes per
hour) to 345tph handling of grain, depending on the specific ship
size. The Portanova is distinguished by its high degree of
mobility and availability as well as by its outstanding cost-tobenefit
ratio. It has many applications, and offers operators a
wide variety of possible applications as an autonomous travelling
or stationary ship unloader with its own energy supply as well as
electrical power supply. The material unloaded is transferred to
fixed conveying systems or directly into rail or road vehicles.
The Portalink. This mechanical ship unloader from Buhler is
designed to handle a wide range of free-flowing bulk materials.
From evaluation and simulation of the optimal unloading process
to design and engineering, structural analysis, manufacturing,
installation, and start-up, the customer’s entire project is handled
by one single, competent and experienced partner. This enables
the influence of individual parameters on overall performance to
be clearly assessed and evaluated, contributing significantly to
optimizing it.
Regular servicing and genuine spare parts guarantee a high
availability of the installation over many years of service. The
Portalink high-capacity marine leg (HL-SKT) allows the intake
boot to maintain the optimal position inside the bulk material. It
also enables automatic unloading down to the minimum bulk
material level inside the ship’s hold.
The possible movements of: displacing the ship unloader;
lifting, lowering, and swivelling the boom; and kick-in/kick-out of
the marine leg provide a large working range inside the ship’s
hold. These movements can also be remotely controlled by
radio, increasing unloading throughputs and reducing berthing
The Portalino. This is a mechanical ship unloader designed for
efficient unloading of grain, oilseeds, derivatives, and non-freeflowing
bulk materials.
Its unloading throughputs are as high as 330tph, depending on
the flow characteristics of the bulk material. The Portalino is
distinguished by its high degree of mobility and availability as well
as by its outstanding cost-to-benefit ratio.
The Portalino is a self-propelled or stationary mechanical ship
unloader powered by a diesel or electric drive. It is best suited
for use unloading ship sizes of 20,000dwt to 40,000dwt.
Rail-mounted or steerable rubber-tyred travelling gears are
available. The Portalino is used wherever existing quay facilities
do not allow any permanent installations.
The material unloaded is transferred to downstream
conveying systems or directly into rail or road vehicles.
Standard Industrie: pneumatic power is behind the
success of its equipment
Standard Industrie (SI), founded in 1978 by Hervé Simoëns, is a specialist in the
design and the manufacture of equipment to facilitate the flow and
conveying of bulk material and powder products. Since that time, Standard
Industrie has always striven to generate value by:
  •   providing innovative and tailor-made solutions;
  •   increasing production performance;
  •   reducing maintenance and production cost for its customers; and
  •   improving working conditions by ensuring for its customers a safe and clean working environment.
Present in over 90 countries through
subsidiaries, the company (160
employees) operates in more than 60
business sectors such as cement plants, mines and quarries, steel
works, power stations, incinerators, foundries, food industries,
chemical industries, glass manufacturing plant, etc.
SI built its success on its AIRCHOC® air cannon
(ten patents registered since Hervé Simoëns
designed the first generation in 1978) which is
considered a world leader for unclogging
material. In the last ten years, the company has
developed a range of new products, including:
LIFTUBE® conveyor optimization system,
industrial vacuuming, mechanized cleaning of silos,
scrapers, rubber conveyor buckets.
The AIRCHOC® air cannon is a pneumatic
unclogging unit, specially designed to break up
the arches and funnels which form in storage
silos and hoppers. Its scope of application has been broadened
during the past 30 years to include the cleaning of build-ups in
thermal processes such as cement or lime works, steel works
and incineration plants. AIRCHOC® air cannons
can also be certified ATEX area 20 for use where
there are risks of explosion. The operating
principle of the AIRCHOC® air cannon consists
of using a quantity of compressed air, the volume
of which varies between 1 and 400 litres (0.04 to
14.13 cubic feet) depending on the type of
AIRCHOC® used. This quantity is released
instantaneously into the storage silo through a
large outlet pipe, directly connected to the
storage unit or where the blockage has occurred.
This creates a powerful air shock-wave aimed
directly into the material, due to the instant
release of the compressed air.
There is a wide range of valve mechanisms
and pressure tanks, which enables SI to
recommend the best possible and personalized
solution for any build-up or clogging problems.
During the previous years SI has also upgraded its air cannon by
designing the fifth AIRCHOC® generation. More powerful still
(at equivalent volume), quieter and safer
but also more robust and compact, this
new AIRCHOC® 5 is recognized as an
optimum solution for these material
flow problems, whilst at the same time
more energy efficient (compressed air
This equipment is available in both a
high temperature and as a standard
The high-temperature version is
specially designed to treat problems
encountered in areas where the
temperatures are high such as in cement
works, lime plants, and incinerators.
The standard version is intended for
applications involving silos, hoppers,
chutes, piping for any kind of process
and material in foundries and in ready
mix concrete plants.

  •   loss of production: dead stock can represent 20% to 60% of the volume of the silos and hopper;
  •   loss of capacity generating functioning costs;
  •   deterioration of the quality of the material itcontains;
  •   damaging the structure by hitting with a hammer to unclog the container;
  •   significant clean-up and maintenance costs;and 
  • safety problems: cleaning silos can be labourintensive and dangerous, especially when the technique involves operators going inside the silo
  • to clean it.
  •   powerful unclogging without structural damage;
  •   100% of storage capacity recovered;
  •   can be used on any kind of structure whether made of steel, concrete, stainless steel, aluminium or plastic;
  •   efficient on all of types of bulk materials stored;
  •   firing sequences, tailor-made and easily set up;
  •   simple and user-friendly technique;
  •   easy to maintain;
  •   quick return on investment;
  •   safe to use; and
  •   extremely reliable.
  •   blowpipes and nozzles;
  •   hanging devices;
  •   safety and control system;
  •   filters and lubricators unit;
  •   automatic control systems;
  •   AIRCHOC® blow pipe isolators;
  •   Airsafe; and
  •   air compressor and buffer vessels.
Is the future pneumatic or mechanical? Neuero defends the pneumatic unloader
The use of pneumatic unloaders is sometimes questioned, writes
Tomas Kisslinger from Neuero. Those querying the effectiveness of
the equipment are often companies that have supplied pneumatic
unloaders in the past, but have not put the effort into research
and development to further the advancement and operating
efficiency of pneumatic ship unloading equipment.
This (in conjunction with problems experienced in the
development of roots blowers for this application) means that
there are some suppliers which promote only mechanical units
rather than pneumatic systems. These companies say that the
future lies with mechanical equipment. On occasion, the best
interests of the client are not properly taken into account when
recommending an unloading system.
In the past, Neuero has come across such marketing attempts
when companies talk about ‘fanless’ units, used to describe a
roots-blower-designed pneumatic unloader. The result can be
that a confused client gets information that is not entirely
accurate, and is wrongly led to believe that pneumatic
technology has no future. Neuero believes that there is a place
for both application, but that the future remains bright for
pneumatic equipment.
Pneumatic unloaders can offer extremely high levels of reliability.
There are some pneumatic systems that have worked problemfree
for more than 50 years — some of these units are still in
Everything seems to be going faster these days. Speeds are
getting faster, equipment is getting smaller. This relates not only
to car engines, but also to the positive displacement pump
industry, which is being increasingly pushed to be competitive.
The development of three-lobe blowers for higher speed —
and consequently higher volumes — caused problems for
pneumatic ship unloading designs using this technology because
of over-optimistic expectations in terms of capacity.
The size reduction (and resulting cost reduction) made this
blower attractive for ship unloader use. However, if the design is
not reliable, it is not of value in such important work.
In reality, what is happening is that the development of
equipment based on roots blowers is suffering mainly because of
breaking mechanical safety barriers.
Traditional millers are used to the roots blowers, but are not
familiar with turbo blowers. It is difficult to persuade them that
today the turbo blower is a better choice than the roots-type
blower for ship unloading applications.
The result of a blower failure is a loss of confidence in the
pneumatic system, especially if the repair takes too long. This
loss of image is difficult to work with, but Neuero’s recent
orders in the milling industry shows that the message is clearly
understood — it is not the pneumatic design that has a problem,
but it is the use of a traditional blower at an extreme operating
The use of roots type blowers should be considered for a
more conservative use — oversize blowers running slower
speeds like it was in the past. This may cost more, but
equipment reliability is key in this business.
Regaining lost confidence is not an easy job. However, it is
valid work because the pneumatic ship unloading system is
extremely reliable, cost efficient, and the most environmentally
friendly solution related to dust and noise. It is also very safe
equipment to operate. In terms of safety, it is not unusual to
meet injured workers that have lost an arm caused by trying to
free a blocked chain… in a mechanical system.
The only negative point of the pneumatic design is the
relatively high installed power consumption. This has been
reduced in recent years with the use of frequency inverters.
Also, it is important to take into consideration the higher
average unloading capacity that pneumatic unloaders deliver over
Is the future pneumatic or mechanical? Neuero defends the pneumatic unloader
Neuero is supplying four 300tph pneumatic unloaders and four 600tph
unloaders to Jeddah in Saudi Arabia, half of which are already in operation.
 an entire ship. Factoring in these two points means that the
‘real’ installed power effectively becomes less.
In recent years, Neuero has developed very cost-effective ship
unloaders in several sizes and different markets. Some examples
are shown below:
Middle East activity
Saudi Arabia — Jeddah: Neuero is supplying four pneumatic
unloaders with a capacity of 300tph (tonnes per hour) and four
600tph unloaders. Half of these are already in operation (see
picture on p44). Also in Jeddah, Neuero has upgraded an old
unloader (see picture above).
Oman Flour Mill — Muscat: one Multiport M600 with
600tph capacity, mounted on rubber wheels.
Salalah Flour Mills — Salalah: one Multiport M300 with
300tph capacity also on rubber wheels (see picture below).
Libya: three Multiports M600 were delivered and are
currently under assembly in Tripoli.
Bahrain Flour Mills — Manama: at the manufacturing stage,
to be supplied one Multiport M300 with 300tph capacity also on
rubber wheels.
The success in this market is related to the quality of the
equipment, and developed service in the region. Neuero has
also upgraded existing unloaders, replacing roots-type blowers
with its turbo blower design.
In Germany Neuero is currently assembling a stationary
Multiport M300 in Mannheim at one of the most modern flour
mills in Germany.
As well as these projects, Neuero is investing in equipment
simulators, using the newest technology.
Using simulators means that it is easier to show customers
the equipment, offering a better presentation that is more easily
understood. Virtual training can be shown for maintenance and
operation. By expanding the use of equipment simulation,
Neuero expects to provide faster client recommendations and
solutions in the future.
Visualization makes it possible to check critical points like the
blowers and show their function.