Bulk Bag Filling Automation and Versatility

Ingredients Handled
Calcium Carbonate.

Control and Metering's Customer
Large Calcium Carbonate producer for Pulp & Paper, Plastics, Sealants, Pharmaceutical, and Food industry.

Customer's Reason For Using Bulk Bags
This customer has been packaging in bulk Bags for several years in order to take advantage of package size versatility and efficiency of discharge by their customers.

Control and Metering Application Solution
The Model C/ABR/CONV Filling Machine was chosen because of the high degree of densification required for Calcium Carbonate, automatic bag removal, and the capability of filling a variety of bag heights without changing the operator access height.

Application Challenges and Their Solution
This project provided several unique challenges:

  1. Bag heights ranged from 30” to 80” in 10” increments. Operator ergonomics had to remain constant regardless of bag size, the machine had to adjust to the bag size from a selection made on the Human Machine Interface.
  2. The 50” high bags had to be double stacked on a pallet.
  3. Double stacked bags had to be compressed before and after stacking.
  4. Pallets with slip-sheets had to be fed automatically to two filling machines in order to achieve the desired packaging rate of 30 bags per hour.
  5. Provisions were made for a future third filling machine with one common operator platform for all three machines.
  6. The filled Bulk Bags had to be automatically stretch-wrapped.
  7. The packages had to be conveyed 100 feet to the warehouse and staged for removal by forklift.
  8. Provision had to be made for a future 50lb bagging machine, which would convey palletized bags on the same line for stretch wrapping and warehousing.
  9. Plant standard Siemens PLC had to be used for controls, with Touch-screen HMI (Human-Machine-Interface) and Profibus Link to the plant’s main control system.

Control and Metering Solutions
The Model C’s hang-weighing technique allows bags of different heights to be rigged from the same location, while the travel height of the vibrating table is adjusted to suit the bag. Control and Metering’s solution for automation was to include an encoder on the moving table’s drive shaft, in order to position the correct travel height as dictated by the operators bag selection on the HMI.

Control and Metering’s unique ABR (Automatic Bag Removal) system was ideally suited for double stacking bags automatically. In the double stacking mode, the ABR shuttle drives into the filling machine to pick up the first filled bag, then drives the bag out and waits for the second bag to be filled (it does not power the package onto the conveyor system). After the second bag has been filled, the ABR drives the first bag in again, and the second bag is stacked on top.

To automatically compress the double-stacked bags, Control and Metering designed a bag press to straddle the ABR shuttle in front of the filling machine. While the second bag is being filled, the first bag can be compressed to expel excess air, flatten the top, and improved stability. This operation is PLC controlled, and does not require operator intervention.

An automatic pallet delivery system was supplied, complete with pallet staging conveyors, pallet dispenser, slip-sheet dispenser, and conveyor system. The system has the capacity of holding up to 40 pallets and automatically stages one pallet behind each filling machine after each filling cycle.

The filling machines are situated side by side with enough floor space left to add a future third machine. The operator platform runs along the back of the filling machines and an extra section can easily be added if and when the third filling machine is required. For pallet dispensing, only two new conveyors will be needed to supply the third machine.

By using conveyors and turntables, the filled Bulk Bags are conveyed back toward the warehouse, but first go through an automated stretch-wrapper to keep the package clean during warehousing and shipping.

After the stretch-wrapper, 50 feet of accumulation conveyors were supplied in 10 ft sections. Using photo-eyes and PLC logic, up to 10 packages can be accumulated and automatically forwarded as the end package is removed in the warehouse.

Provisions were made for the future addition of a small bag filling system. The outfeed conveyor controls were designed so that a signal from a photo-eye would enable the Bulk Bag conveyor system to receive packages from the small bag filling system, and send it to the stretch-wrapping station and warehouse.

Although Control and Metering’s standard control package utilizes Allen-Bradley PLC, the design team’s experience and versatility enabled them to supply the Siemens PLC based control system as requested by the customer. The Profibus link will allow the plants Process Control System to keep track of packaged quantities and coordinate process controls to blend the various amounts for individual shipments, while minimizing wastage.

Why The Customer Chose Control and Metering
The customer had bought a Model C/ABR/CONV machine approximately six years previous to this project. Although the total system was much less complicated, they were already familiar with the advantages of the patented vibration table and hang filling/weighing. A total of six suppliers were asked to bid on this large project. Control and Metering demonstrated their ability of supplying a ‘complete package’ including pallet dispenser, slip-sheet dispenser, all conveyors, filling machines, bag compressors, and stretch-wrapper, at a competitive price. Key features were package quality due to hand filling, double stacking capability, and dust control.

 For further information on Automation and Versatility contact us at info@spiroflow.com or call 1-704-246-0900