Automated Big Bag Unloading and Conveying

Process Powders: cement

Unloading and conveying of cement

Unloading of cement from 1 ton big bags with pneumatic transfer of material to silo storage

The client, located in Canada, is a gold mining company dealing in the production of precious metals. The project goal was to upgrade their system for a convenient, clean and safe solution to empty 1 ton cement big bags. Production goals were to operate at a rate of about 100 big bags per day within a limited and restrictive area.

The Palamatic Process Solution

Our team of engineers designed a solution for the automated conveying, staging and unloading of the big bags. Material was temporarily stored in a buffer hopper that fed a dense phase pneumatic conveying line to transfer the cement material to a silo storage unit. With limited space availability in mind, the Palamatic team minimized the system’s needs for operator intervention.
 

Big Bag Conveying and Pallet Stacking

In order to limit the need for manual operator intervention, the system design starts with a motorized belt conveyor for the buffer storage and transfer of big bags to the unloading station. Once in place, an electrical hoist can handle and lift the big bags from the conveyor to the big bag unloading station.
An operator then utilizes a pallet manipulator to safely unload the empty pallets from the motorized belt conveyor to the pallet storage area. The manipulator is a vacuum lifter that allows easy and effortless lifting of heavy or large objects (e.g., bags, drums, pallets, etc.) Furthermore, an access platform in integrated into the system to allow for easy access to all areas of the big bag unloading system for maintenance.

Automated Big Bag Unloading System

Palamatic Process offers our EasyFlow® EF100-200 high-speed big bag unloading station which provides the automatic emptying of big bags without operator intervention. The cutting, handling and evacuation phases of the big bags are controlled by the integrated PLC. The handling and evacuation are both carried out by the big bag handling cross attachment with automatic release function.
Boasting a processing rate of 20-40 big bags / hr, the objective of this process station is to offer automatic big bag opening, dust containment of the powder, increase productivity and a safer work place, all while minimizing the need for operator intervention. The mechanical roller conveyor stages the big bag under the electrical hoist with handling cross.

An operator attaches the big bag handles on the handling cross and the automated hooks secure the big bag for lifting. The jumbo bag is then transferred inside the dust containment cage and lowered onto the burst spike. The weight of the big bag causes the burst spike to cut open the bottom of the super sack. Once the FIBC is fully empty, the bag is transferred to the compactor hopper for automatic release and compaction within a contained polyethylene sheath.

For this specific project, a big bag compactor was used for the function of higher amounts of big bag production per day and compaction of the waste. The plexi-glass containment field around the hoppers and unloading station help contain any dust from escaping to the work atmosphere. Manual doors swing open to allow easy access for entry of the big bag to be emptied into the downstream process. A double electrical hoist with double discharge hoppers was implemented into this design to allow the loading of two big bags at once for increased unloading rates. Massage cylinders were also used to help break up material flow problems within the big bag during its emptying cycle. A buffer hopper temporarily stores the material from the big bag for feeding of the dense phase conveying line.

Level probes are integrated into the buffer hopper to provide feedback to the controls for high and low level indication. Further flow aid devices, such as pneumatic vibrators and pneumatic hammers, are also integrated into the hopper to further promote good flow for additional powder handling solutions. At the discharge outlet of the buffer hopper is an EC50 lump breaker. The lump crusher provides the pre-crushing and deagglomeration of materials that have been in extended periods of storage or exposed to moisture and have formed hardened clumps of agglomerated powders.
 

Bulk Bag Compacting Process

A compactor was used to help with very high rates of big bag disposal. The compaction force of the ball press is 50 tons with an 87 second cycle time. The material is compacted and the formed bale is secured and tied via metal straps. For further safety precautions, the outlet of the ball press is surrounded by a safety cage. If an operator opens the safety cage doors, a safety switch will send a signal to the baler to turn it off.
 

Material Transfer Process

Dense Phase Conveying is a powder handling solution for the transfer of abrasive or fragile bulk materials. Due to the abrasive nature of cement powder, this pneumatic conveying system used high pressure pockets and low air velocity to both prevent the material from degrading and wearing through the equipment over time.
High pressure conveying with low velocity speeds extends the life of the material transfer system. The process line utilizes a pressure pot to both store and transfer the powder materials. With a 342 liter capacity, material is fed into the pressure chamber via an inflatek valve (dome valve) which has the ability to seal against high pressure via its inflatable elastomer seal. Further benefits of this valve help protect against wear and abrasion due to is shape and inflatable seal.
 

Dust Control and Containment

An independent dust filtration unit captures any fine particulates coming off of the bulk unloading and material transfer process.  The dust is separated from the air flow by means of dust filter elements with flat or folded pockets. This particular dust control system is connected to the pneumatic conveying line. The dust collector feeds the finer particulates back into the pressure conveying line via a rotary airlock valve.
 

Electrical and Automation Control Panel

For control of the process line, our Pal’ Touch control system is integrated into the process to allow an operator to control all parts of this system: big bag unloading, big bag disposal, material storage and material transfer to silo storage. Palamatic Process’s automation and computer engineers included user friendly raw material inputs, lot traceability, operator identification and dosing reliability. Our staff and client were able to clearly communication during the project execution phase to provide a final design that worked well in the field.

Since 1992, Palamatic Process has provided equipment to over 2000+ installations in more than 30 countries. We offer knowledge and expertise in all manner of bulk powder handling equipment solutions. Examples of our equipment offerings include: conveyor systems, bulk process equipment, pneumatic conveyor systems, dust collection, and bulk handling systems.
Contact one of our experts today for assistance with needed material handling solutions and to request a quote.