Except
for a very few applications, gone are the days where a company asks a local
fabricator or their own engineering team to concoct a bulk bag support frame –
whether to fill or empty.
The
worldwide acceptance of bulk bags has resulted in tremendous changes in bulk
material handling practices. In some instances, even the pharmaceutical
industry now uses bulk bags to replace rigid Intermediate Bulk Containers since
their associated filling and discharge systems offer them proven advances in a
hygienic and “high containment” operation. Bulk bags also eliminate the need
for cleaning and re-validation procedures.
Specialist
suppliers offer bulk bag filling and discharge systems with high levels of
containment. ‘Homemade’ fabrications can never match the safety, reliable discharge
and containment offered by specialist suppliers demanded by today’s industrial
practices and required through current legislation.
This
article will review some of the advances made in Bulk Bag Discharge and
Filling. It will also offer points to consider in selecting a Discharger or
Filler for your plant.
Bulk Bag Discharging
Given
the potential for problems with all but the freest flowing of materials, it is
essential to select a supplier for whom Bulk Bag Dischargers are a key product
line. Spiroflow Systems is one such company. With over 35 years of materials handling
expertise, the company is among those setting the standards in high containment
bulk bag delivery system.
a. High Hygiene Clamping Device
One
recent development by Spiroflow is an upgrade of their ‘high-hygiene’ liner clamping
device. Loose liners in bulk bags can pose problems for processors and can be
the cause of dust and spillage during both discharge and disposal when the bag
is empty. Spiroflow offers a liner spout clamping system that assures total
containment of the bag contents. A two-way process, containment prevents
exposure of the operator and the environment to hazardous products and
conversely ensures that neither the operator nor the environment contaminate
the product.
The
new clamping device only requires a spout length of 19 in. (475mm). This makes
it easy for the operator to manipulate the spout into the clamping system. The
clamp is operated either pneumatically or manually. The clamp may also be used
for unlined bulk bags, clamping directly to the bag spout.
Previous
clamping methods required a liner length of almost 35 in. (850mm). This length
made it more cumbersome for most operators to locate in the clamp. In addition,
the liner length was not always available, causing the processor to request
bags with tailored liners or longer outlet spouts from the material supplier.
The
hygiene spout is housed within a containment enclosure usually connected
to a filtration system. Access to the hygiene clamp is through large double
doors, or a glove compartment, depending on the hazard level. The containment
enclosure may be fitted with an integral “safe change” HEPA filter.
During
discharge, the bag and liner are kept in tension to promote a smooth flow of
product and to ensure the bag is totally emptied. Tensioning also prevents
distension of the bag and/or liner and avoids it becoming entangled with moving
parts of the downstream process or integral conveyor below!
b. Integral Liner Clamping System
Another
recent innovation is that some bulk bag manufacturers are offering bags with an
integral liner clamping system. Spiroflow, for example, as an option in their
sanitary model includes a provision to accommodate such clamping systems. This
is another example of the ever-increasing armoury of “total containment”
developments for those involved in the discharge of hazardous or sensitive
materials from bulk bags. The system is designed for bulk bags with formed
liners and are ideal for dairy, food, fine chemical and pharmaceutical
applications where high degrees of containment are essential.
A
liner clamping system typically includes a docking seal comprising of two
interlocking rings secured to the liner spout – usually custom fitted by the
bulk bag manufacturer. When ready to empty, the bulk bag is lifted onto the
discharge station and the liner, with the docking seal pulled down and mated
with a special docking unit by way of a clamp. The bag can then be untied and
the product released in a dust tight manner with no contamination of the
product, the operator or the environment.
c. ‘DoverPac’ Bulk Bags
Another
development is the ‘DoverPac’ Bulk Bag that offers advanced barrier and
isolation for the pharmaceutical industry. Many pharmaceutical companies around
the world employ flexible containment solutions, such as the DoverPac from ILC Dover,
not only at their plant, but also at critical suppliers who provide Active
Pharmaceutical Ingredients (API’s) to their manufacturing operation. By
shipping API’s in these flexible systems, the material can be readily loaded
into the process vessel without costly or time consuming on-site transfer
operations. DoverPacs permit effective product transfer without the use of
Personal Protective Equipment (PPE). They also address the need for larger
volume API transfer without sacrificing containment. Spiroflow Systems, for
example, is experienced in the manufacture of Bulk Bag Dischargers for bags
incorporating ‘DoverPac’ Bags.
d. Looplifter®
Then,
there is the Looplifter®. Looplifter® holds the loops open of any bulk bag
allowing the forklift operator to handle the FIBC without either leaving the
seat or seeking any external assistance. Looplifter® allows the loops to be “squashed”
downward when further bags are stacked on top. Even after lengthy compression,
the ‘loops’ always return to a fully open position.
e. Quick –disassembly Bulk Bag Discharger
In
response to the pharmaceutical industry in particular but, equally well suited
for dairy and some food applications, Spiroflow have introduced an all-new Bulk
Bag Discharger. This Discharger is well suited for critical applications where
hygiene and/or rapid dismantling without tools are essential to avoid
microbiological growth and/or cross-contamination between batches.
f. Other Developments
Bulk
Bag manufacturers are now offering bags with side ‘tunnels’ instead of loops.
Side ‘tunnels’ are in fact rolled-over extensions of the side panels. These
also make it easier for lift truck operators to pick up a bag without manual
assistance.
Another
development, ‘Pallet-Less’ bulk bags, is one of several innovations that make
the need for separate pallets a thing of the past. Not only do ‘Pallet-Less’
bulk bags include integral forklift locations that contribute to overall
hygiene, they free up more space for the product that is particularly important
when loading bulk bags into ISO containers.
g. Points to Consider in Selecting a Bulk
Bag Discharger
In
selecting a Bulk Bag Discharger, here are 19 points to consider:
- Will the discharger
handle different sized bags? - Can the discharger cope
with lined or unlined bags? - Can the bag discharge
poor flowing products? - Will a hoist or a
forklift truck load the bag? - Can you control the flow
once the bag is opened? - Do you need to tie off
partially empty bags and remove them from the discharger? - How sure are you that the
discharger will completely empty the bag? - Does your product need to
be discharged by weight or by volume? - Do you need a device to
restrain and/or remove liners? - Is an integral conveyor
required to transfer product to another location? - Will the discharger fit
into the available headroom? - Does the discharger need
to be mobile so that it can serve more than one location? - Does your application
need a fall back provision to accept 55 lb (25 kg) bags if your supply of
product(s) in FIBC’s is interrupted? - Does your application
have to meet the hygiene requirements of the USDA, the FDA, OSHA or other
regulations? - What dust control
measures must the discharger include: - When untying the bag
spout? - While the product is
being discharged? - When the liner is
removed? - When the bag is removed
and folded for return or disposal? - Is the discharger working
in a hazardous environment? Do you require electrostatic containment or
monitoring? - Does the supplier you
select have good references for similar applications? - Does the supplier you
select have in-house testing facilities to demonstrate the effectiveness
of their equipment on your product? - Does the supplier you
select have effective spare parts and technical and engineering support
programs?
Bulk Bag Filling
a. Recent Developments
Some
manufacturers such as Spiroflow Systems are setting the standard for high
containment bulk bag filling. Perfectly upright and stable bulk bags can now,
for example, be filled to the required weight in less than one minute. A minute
is also about the time it takes to rig a new bag into position and to remove a
filled bag at the end of the cycle. This typically equates to a filling rate of
around 20 bags an hour. This all happens dust-free and without spillage.
Upright and stable bags are essential if the bags are to be stacked,
transported by highway or loaded into shipping containers at a port. A typical
Bulk Bag Filler includes many of the latest state of the art developments. For
example, new bag fillers such as those from Spiroflow are furnished with
programmable controllers designed to increase filling accuracy and cycle speed.
Automatic gain-in-weight systems monitor and control the filling process within
an accuracy of +/- 1%. These fillers are ideal for companies seeking NEPT
approval. There are also many custom features available including:
- Retracting bag hooks that
simultaneously open and close all bag hooks for fast attachment/detachment
of the bulk bag loops to the filler. This makes rigging of the bag to the
support frame quick and easy. - A filling nozzle and
inflatable mechanical seal between the filler and the bag for a sanitary,
dust-free operation. - Pneumatically powered
support arms that let the operator adjust the height between filling
cycles to accommodate various sized bulk bags. - Liner inflation device
that ensures the integrity of the bulk bag by inflating the liner with
ambient air, creating slight positive pressure to remove any wrinkles that
may cause instability or subsequent difficulties during discharge. It also
ensures full maximum material capacity. Air displaced through filling is
vented through the annulus that surrounds the filling spout. - Electric or pneumatic
vibrators that improve material densification and compacting during the
filling process for better storage and transport. This increases
productivity and maximizes the use of space. Timed vibrations also occur
during the weighing cycle at predetermined intervals. The vibration
technique employed by Spiroflow, for example, ensures that it is exerted
in the vertical plane only for maximum effect. This makes bags stable and
safe to handle. - A roller bed system that
ensures faster off-loading of filled bags to increased productivity. An
automatic bulk bag loop releasing mechanism enables filled bags to be
automatically removed by a roller bed system. This system ensures faster
off-loading of filled bags to increase productivity.
b. Points to Consider is Selecting a FIBC
Filler
In selecting Bulk Bag Filler, here
are 15 points to consider:
- Will the filler handle
different size bags? - Are the bags lined or
unlined? - Are the bags going be
filled by weight or by volume? - If by weight, does the
filler need NEPT approval? - Is it quick and easy to
rig in new bags safety? - Are the bags pre-inflated
before filling? - Is the filling process
completely dust-tight? - Does the filler stretch
the bag and compact /de-aerate the product during
filling? - Is there provision to
vent the displaced air safely to a filtration system? - Can up to twenty 1,000 kg
(2,200 lb) bags be filled an hour? - Can filled bags be
removed by forklift truck or conveyor? - Can filled bags be
automatically removed after filling? - Does the supplier you
select have good references for this and similar applications? - Does the supplier you
select have testing facilities available to demonstrate the effectiveness
of their equipment on your product? - Does the supplier you
select have effective spare parts and technical and engineering support
program?
Conclusion
There
have been numerous developments in Bulk Bag Discharging and Filling over the
years that you need to consider before selecting a supplier for your system.
The points to consider in selecting a Discharger or Filler should also be
reviewed before making a final selection.
About Spiroflow Systems, Inc.
Spiroflow
is a worldwide supplier of a wide range of both standard and custom powder
handling equipment, specializing in Bulk Bag Dischargers and Fillers, a range
of Flexible Screw, Aero-Mechanical, Drag Conveyors and Pneumatic Conveyors, a
range of 50 lb Bag Packing and Unloading equipment and Flexible Storage Silos.
The company offers a wide range of innovative designs and design options.
An
in-house test facility offers a free on-site and on-line service to customers
to analyze and demonstrate material flow properties under actual operating
conditions. This, in turn, sets the parameters for selecting the most suitable
handling method for your process and ensures equipment is installed properly.
Any system tested in our test facility is guaranteed.
For
more information about this article, contact Spiroflow Systems, Inc. at 704-291-9595,
FAX 704-291-9594 or e-mail [email protected].
Spiroflow can also be found on the web at: www.spiroflowsystems.com.
About David Hesketh
David
Hesketh is Vice President of Engineering for Spiroflow Systems, Inc. Hesketh
has over 20 years experience in power handling and in particular the design and
development of conveyors and bulk handling equipment. He has held senior
positions at Spiroflow and for many years. He worked for Spiroflow in the United Kingdom before relocating to the United States.
Hesketh holds a BSc in design and manufacture from the University of Central
Lancashire, England.
