Norpak Case Study: Colour Detection and Sortation System

What Is Color Recognition and How Does It Work?

Utilizing the VCS110 Series color sensor, the sensor can differentiate up to ten seperate colors. The colors are programmed into the unit with a push-button keyboard on the sensor. The light source of the sensor is a durable, high-intensity white light. The light is emitted from a fiber optic cable attached to the sensor and is reflected by the pallet color back to the fiber optic head. This reflected light is sent to a three-channel receiver, whereby the colors of red, green, and blue light are evaluated, converted into digital signals as intensity values, and processed in the sensor's microprocessor. These signals represent the color of the pallet, and direct the appropriate colored pallet to the same associated color pallet stacker.

Product Being Handled:

Stacks of assorted colored pallets (Blue, Green, Yellow and Orange). The pallet stacks can consist of 15 Pallets or 1500 pounds maximum weight.

Features and Description of The System:

The sort process begins by the safety doors of the pallet dispenser opening and the lift table rising, allowing two pallets to be manually loaded onto the scissors lift platform. The magazine will dispense the first pallet and leave the second pallet suspended in the dispenser fingers to act as a loading platform. An entire mixed colored pallet stack can now be placed into the Pallet Dispenser cavity. In the event that the last pallet is to be dispensed, the first pallet selector switch can be used to dispense this last pallet onto the chain conveyer. The Pallet Dispenser containing a full load of pallets will dispense one pallet at a time onto the chain conveyer. Here they will be detected by the VCS110 series color sensor ands, and identified by color and destined to one of five pallet stackers. The chain conveyer at this point will start to run and the appropriate stacker lift table will rise to catch the bottom pallet board. The chain conveyer will stop and the scissors lift table will rise pushing the pallet upwards so that the top boards of the pallet are located above the pallet stacker support fingers. The lift table will then lower leaving the pallet suspended on the stacker support fingers. This procedure will repeat until the stacker has become fully accumulated. A full accumulation condition will be detected by means of a proximity photocell located at the top of the stacker magazine.

What Happens When?

- Under full accumulation of a pallet stacker, an alarm horn will sound and a yellow beacon will flash to indicate the pallet stack has become fully accumulated. The pallet sortation system will continue to run and sort pallets as long as the color of the pallet is not the same as the accumulated stacker.

- To unload an accumulated pallet stacker, the pull cord associated with the Pallet Stacker must be actuated to open the doors and halt the operation of the system. At this time the alarm horn will be silenced. Once the load of pallets has cleared the photo-proximity sensor located at the top of the stacker, the red light will be turned off. The stacker doors must then be closed. The system will then automatically restart and the procedure will repeat.

- In the event that the pallet is of the same color as the accumulated stacker, the system will cease to sort and a red light will be illuminated and the alarm horn will sound until the accumulated stacker has been unloaded.

- Pallets, which cannot be identified by color, will be destined to the last stacker of the series.

- Pallets will be tracked from the Pallet Dispenser to their appropriate Pallet stacker destinations. When a pallet has failed to arrive in a given time frame, the red light will be illuminated and the alarm horn will be sounded. The operation of the Chain Conveyor will be halted. This will now require manual operator intervention to determine the problem. Once the problem has been corrected the operator must press the system-reset button to re-energize the system.