When docking and undocking containers at weighing stations, cross-contamination can occur and dust can be released. But not with the AZO CleanDock. It "thinks" for itself, thus increasing process reliability and reducing commissioning times – thanks to the control system CPX-CEC from Festo docked directly to it.
"Our systems transport and dose all possible kinds of bulk materials", explains Frank Pahl, Development Manager at AZO. They range from milk powder and ingredients for baby food to pharmaceuticals and detergents as well as different plastics and pigments, for example for wet paint production. A handful of flour contains more particles than a whole truck full of pebbles. The infamous angel hair can form when handling plastic, while higher degrees of grinding and finer powders with smaller particles in cosmetics and pharmaceuticals require intelligent solutions.
Product purity and employee protection
Product purity and employee protection are top priority for chemical, pharmaceutical and food manufacturers. "Cross-contamination and the release of dust must be avoided", says Pahl. When handling bulk materials, dust from allergenic food, for example, can pose a health hazard for operating staff. Attention must also be paid to explosion prevention and protection. Different containers for transporting and handling bulk materials such as big bags, drums, sacks and mobile containers require different system designs. Flexibility is what is needed.
"For the product to stay where it belongs, in target containers and the dosing device, both must be closed before docking takes place", emphasises Pahl. This sounds simple, but isn't. "We definitely don't want any of the product adhering to the inside of the dosing device's downpipe to fall out before coupling and after decoupling and soil the floor or release dust into the ambient air."
That is why AZO developed the CleanDock. The dosing device and container remain hermetically sealed before and after filling. "While some double-cone systems available on the market do not consistently ensure freedom from carry-over effects, the CleanDock always guarantees this through the line contact of the components involved in the sealing process", says Pahl. By using this technology in the CleanDock, AZO is very deliberately placing itself between classic docking systems and the containment systems familiar from pharmaceuticals, such as split valves.
AZO enhanced the CleanDock together with its long-standing automation partner Festo, focusing on fast commissioning, error reduction and greater safety during filling. A decentralised control system in the form of the CPX-CEC from Festo in combination with the valve terminals CPX/MPA allows the CleanDock to "think for itself" and actuates the pneumatic drives.
Docking of the active section to the passive section takes place using pneumatic linear drives from Festo. They are also used for opening and closing the cone seal in the active section for filling the target container as well as locking and tightening the active and passive sections. A pneumatic knocker is used to loosen any bulk material residues stuck in the dosing device.
"Some bulk material plants store more than 80 raw materials in silos", explains Frank Pahl. "The most CleanDocks we have installed in a system so far is around 60." With so many filling stations, the programming and commissioning effort would normally be expected to be high. The probability of errors also goes up as the number of units controlled via the process control system increases. "Controlling the CleanDock decentrally speeds up the commissioning of a system and reduces the risk of errors", says Pahl. "All the process control system does is give the command for docking and undocking. The CleanDock looks after all the detailed operations itself. Programmers no longer need to look after these detailed processes on-site during commissioning."
Modular, flexible, pioneering
The modular electrical terminal CPX from Festo with integrated controller CEC and valve terminal MPA provides a uniform interface for the decentralised intelligence and enables the complete control of machines or more complex subsystems. As an automation platform for electric and pneumatic components, it connects pneumatic and electric control chains to different automation systems and company-specific standards simply, quickly and flexibly. The entire system is easy to configure using CODESYS. Interfaces are reduced, engineering and handling processes are simplified and the reliability of machines and plants is increased.
Another key point is the modularity of systems, since automation is increasingly decentralised on individual system modules. All the process control level does is set the pace. While the process control system calls up a function, it does not need to have a detailed knowledge of the stored process steps. This is taken care of by intelligent modules such as the CPX-CEC with valve terminal MPA at AZO.
Together towards a modular future
The implementation of AZO together with Festo follows the recommendation of NAMUR/ZVEI, system builders and operators as well as research institutes. Decentralised and complete automation of individual modules reduces complexity. For system operators, this shortens the time to market. Individual modules can also be produced for stock and adapted without a great deal of effort. Systems can be easily expanded with additional modules and their flexibility increased. Festo is one of the automation experts that is constantly enhancing the topic of modularity with its products and solutions.