This unique project involved Fresco getting involved in the early stages of the project assisting in the detailed design of the materials handling systems. The plant had a very tight specification on dust emission and system dosing accuracy which added to the difficulty of the project.
Some other criteria included the ability to load and unload the bulk bags in a central location to keep the process area clean to near pharmaceutical standards. This meant the whole bulk bag unloading station was removed from the process area by overhead gantry crane and taken to an area where the bulk bags could be changed.
The system comprised 4 rows of 10 bulk bag unloader stations with each row having an overhead gantry crane. Fresco developed a quick connect system for the gantry crane that allowed the attachment and detachment of the bulk bag unloader station by the operator without having to manually intervene.
This concept provided a cost effective solution to the application saving the customer from purchasing 40 individual electric hoist and trolleys.
As all 40 units where for different materials we needed a versatile design that would accommodate the huge range of bulk densities, particle sizes, flowability and numerous bulk bag dimensions.
This was achieved using many features from our standard range of bulk bag unloaders including the height adjustment for the bulk bags. Each bulk bag unloader has four fully adjustable sturdy uprights, which allows for any size of bulk bag by simply removing the retainer pins and adjusting the vertical height of the support frame pockets.
The various sized bulk bag discharge spouts easily clamped into our spout clamp providing a dust tight seal preventing dust escaping to the surrounding area.
During the bag removal stage the dust collector evacuated air from the bulk bag collapsing it allowing the operator to remove and dispose of it safely without having to crunch and roll up the empty bag releasing dust laden air into the environment.
A liner tensioner wound up the liners from some of the bulk bags preventing them from slipping into the hopper above the metering screw feeder. This would have restricted the flow of product from the bulk bag causing inaccuracies with the flow of material into the mixers below.
Each metering screw feeder was fitted with an agitator to condition the product prior to entering the screw ensuring consistent flow of product regardless of the head load. A flow restrictor fitted to the metering screw feeder discharge spout prevented material spilling or flushing while the bulk bag unloading station was in transit to the bag change position.
The electrical system incorporated motor starters, overloads and a variable speed drive so the metering screw feeder screw could be slowed to a dribble feed in the final stages of loading the mixer. With the mixer on loadcells weight feedback controlled the system providing high accuracy.
The unusual voltage in Japan was a challenge to our electrical engineer but this was overcome with the use of a Bonfiglioli process power converter. Each system was required to be supplied with a plug so it could travel with the bulk bag unloader station during the bag change. The system was fully tested in our workshop prior to shipping allowing for a shortened installation/commissioning period.
Installation & commissioning was supervised by a skilled Fresco Systems Engineer on site in Japan. This was carried out with the use of a local contractor. Although the language barrier was a little difficult at times the whole job was completed without issues. The system was so successful it will now be repeated at another of the customers existing facilities.
