Improved export packing
UK. The Evesham production facility of Dawn Foods has introduced a Flexicon bulk bag discharger and batch weighing system to transform its food processing and packing line. Initially geared up to handle bakery mix in 25-kg bags, the line now has the flexibility to pack bags or one-tonne bulk bags depending on requirements.
From its manufacturing and distribution centres around the globe, Dawn Food Products Inc supply anything from the most modest of small family bakeries through to international chains. Evesham produces original US-based cake mixes in 25-kg bags as well as finished products such as muffins and chocolate cakes for external sales to the retail/wholesale market, as well as palletised supplies to its sister company in Holland.
Producing the recipes requires bulk raw materials (flour and sugar) to be blown from a combination
of five external 40 tonne silos to one of two mixers sited within the
dry mix plant; one for chocolate and the other for
non-chocolate mixes. Minor ingredients are manually dumped into the mixer using an
adjacent manual dump station. Load cells within the hopper control
the amount of additional ingredients. One-tonne batches of a recipe
are metered by gain-in-weight technology using load cells located under the
mixer.
Recipes are gravity fed from
the mixer and weighed into 25-kg bags that are stitched, labelled and despatched and
loaded onto pallets for shipment to Holland or for delivery to
in-house bakeries. Ingredients for the retail/wholesale trade are gravity fed through
a sieve into 150-kg capacity mixing vessels where water addition creates a final
mix to be sent to a depositor in readiness for oven baking in the
company's own in-house bakeries.
Bag shipments to
Holland (40 bags per tonne) represent a major task in terms of production
volume, and the procedure to dispense mixes for the oven process was slow
and costly. Production tended to be labour intensive, time consuming and
hazardous and Flexicon was given the brief to provide a more efficient
system of bulk bag despatch to Holland and improve the batch process for
the depositor line.
Using a fork lift truck, an operative positions FIBCs in front of the frame and attaches the carry handles to a cruciform connected to an electrical hoist, enabling the FIBC to be located onto the frame above the receiving hopper. Once the setpoints for the batch have been reached, raw material gravity feeds into a 3-m flexible screw conveyor and passes up through 45 degrees, through a transition discharge adapter and into the gain-in-weight controlled hopper.
Flow slows to a trickle speed as the target weight is reached with in-flight material accounted for in the gain-in-weight calculation. A butterfly valve is then activated to release material, and flow is simultaneously halted until another batch is requested. Water is added downstream to the batch for further mixing in readiness for the depositor and oven bake process.
Controlled release of material to the hopper is achieved by Flexicon's Spout-Lock™ clamp ring positioned above a pneumatically actuated telescoping tube. These enable the operator to make a quick, dust-tight connection between bag spout and hopper. Under push-button control, the telescoping tube raises the Spout-Lock™ clamp ring assembly, allowing the bag spout to be pulled through the ring and enabling an operator to seal the clean side of the bag spout to the clean side of the telescoping tube.
It then continues to lower until the bag spout is pulled taut. Once the spout is untied, the telescoping assembly exerts continual downward tension on the spout, elongating the bag as it empties into the receiving hopper via a hopper screen. The dust-tight seal between bag spout and clamp ring allows fully open discharge from the bag with no risk of dust inhalation by operatives. A low-level sensor provides product level status in the FIBC.
Prior to the project, extensive testing was carried out at Flexicon's test facility. Now, the combination of bulk bag dischargers, flexible screw conveyors and hoppers with load-cell data capture have enabled the client to more efficiently use manpower, reduce manual handling, eliminate waste through residues left in bags, increase speed and improve quality control on the depositor line.
www.flexicon.co.uk
|
11:42 05/05/2011
Batching fragile products
A Middle East-based
supplier of a mixed fruit and nut product required a means of loading
300-kg batches into bulk bags without damage. The product contains
whole walnuts that are particularly
fragile.
Spiroflow has a long history of developing its ranges of bulk bag fillers and dischargers to meet the needs of individual customers.
Speaking about the application, Keith Simpson, Spiroflow’s marketing manager said: "This challenge was an excellent opportunity for us to apply our ingenuity and vast bulk materials handling experience. The result is a new 'Rise and Fall' model for our Bulk Bag Filler range".
To avoid the problem of fruit and nuts
falling the full height of an empty bulk bag, the bottom of the empty bag
is raised up to just below the outlet of the filling tube. The gap between
the end of the tube and the bottom of the bag is just sufficient to allow
nuts to gently flow into the bag without damage. The bag is then lowered
slowly to allow filling to continue.
For this particular application, a total of six Rise and Fall fillers were supplied. Four have load cell weighing to OIML standards and gentle vibration to consolidate the bag contents. Two units supplied have the vibration feature but without the weighing facility.
Vibration not only makes the bags aesthetically pleasing but, more importantly, safe to handle, transport and store. Four fillers with the weighing capability were supplied with printers to generate labels for weight, date, time and batch number.
If necessary, the new models can incorporate all Spiroflow’s standard bulk bag filler options such as pallet dispensers, pallet delivery conveyors, bag inflation, weighing, displaced air filtration, vibration and automatic removal of filled bags.
www.spiroflow.com
|
21:45 29/03/2011
Efficiently handling TiO2
UK.
Flexicon bag dump stations have become an essential element of Ameron International's manufacturing plant that produces protective PVC lining products for large concrete sewer pipes.
Utilising high velocity fans and two-stage filtration, the units are said to have dramatically improved the working environment, drawing airborne dust away from the operator and reducing build-up on machine surfaces. In addition, the performance of a Flexicon screw conveyor for handling a difficult paste-like material has improved transfer rates six-fold.
The production process requires precise quantities of titanium dioxide (TiO2) to be weighed and blended with a PVC resin prior to extrusion of the compound, to impart UV resistance and a translucent white colour. Previously, plant personnel had to cut open bags and shovel TiO2 powder into a bucket on a scale. On reaching the target weight, material was dumped into a blender containing the main ingredient PVC to make up a 2 per cent concentration.
Handling the
powder produced dust. "If you open a bag of titanium dioxide and dump it,
the powder can become airborne," explains James Gross, product engineer at
the plant. TiO2 powder is cohesive and compressible tending to pack, cake,
bridge and otherwise resist flow. "It's a powder that acts almost like a
paste, so it's problematic to move," Gross
says.
Gross researched enclosed systems that would be able to handle the paste-like powder and decided on a Flexicon two-part system consisting of a bag dump station with integral flexible screw conveyor.
Pallets of 11-kg bags of
TiO2 are now stacked next to the bag dump station on an elevated dock - a
waist-high bag tray support providing a work surface for operators to
stage, clean and open bags prior to dumping. The bag dump station's dust
collection unit is mounted directly on a 150-litre floor
hopper.
Opening the hopper lid activates a high velocity vacuum fan allowing operators to dump TiO2 through a screen. Airborne dust is drawn onto two high efficiency filter cartridges, an automatic reverse pulse filter cleaning system ensuring that dust buildup on the filter surfaces falls into the hopper.
At 760 mm square x 965 mm high, the
hopper offers a high flow configuration that causes TiO2 to topple and
flow toward and down the steep back wall, preventing bridging between the
side walls. A pneumatic vibrator and agitator have been incorporated into
the system to promote flow of material to the conveyor inlet.
When the blender calls for TiO2, the operator activates the conveyor, as well as the vibrator and agitator in the hopper. The controller automatically stops the conveyor when the target weight in the bucket reaches 2.5kg. At this point the remaining powder in the down spout trickle feeds into the bucket bringing the final weight close to the required 2.7kg. "We're achieving batch weight accuracy of approximately ±0.01kg, which is many times more accurate than the old system," Gross reports.
Initial estimates by Gross allowed up to three minutes for depositing the required 2.7kg, given the variable flow characteristics of TiO2, but the task is now accomplished in 30 to 45 seconds since the installation of the system. With the new system an operator can empty the filled bucket into the blender without removing it from the dust containment box, ensuring containment throughout the system.
In addition to protecting workers and keeping the surrounding plant area clean, the system reduces material waste and eliminates the need to clean a remote dust collection site.
www.flexicon.co.uk
| 12:23 03/03/2011
