Hands off!

In the production of medication and cosmetics, excellent hygiene in the process and plant area plays a key role – and is enforced by strict regulations worldwide to protect the consumer. But in a competitive global market, companies need to make their production processes economical. Technology specialist Bürkert can help by offering decentralised automation at process level.

	Decentralised automation with integrated valve systems.

In the field of process valves, conventional automation solutions, including control cabinets with valve terminals, I/O systems and field bus interfaces, normally require costly hose connections and wiring. With this type of technology, the valves at field level are connected to the central control unit through a large number of long control air lines and discrete feedback connections.

Apart from the high costs of time-consuming planning and installation of such solutions, they are not entirely without problems as regards hygiene.

An alternative to these systems is the use of intelligent process valves from the fluid technology specialist Bürkert. In contrast to concepts based on control-cabinet automation, the only tasks left to the central process control system in Bürkert’s decentralised solutions are control and status monitoring. At field level, pneumatically operated process valves are used. These can be equipped with all the required automation components, such as pilot valves with manual actuation, electrical feedback units and optical status indicators, field bus interfaces and even positioners and process controllers.

One line for up to 62 valves
By integrating an AS-interface as a field bus interface, processors can take full advantage of the features that decentralised automation has to offer. A two-wire line connecting the PLC with up to 62 valves is all that is required for power supply, feedback and communication.

Each process valve is individually connected to the main compressed air supply line installed in the field, so that these connections are kept as short as possible. This reduces the number and length of hose and wire connections, as well as the number of required control cabinets, to a minimum. The valve systems themselves are designed according to the EHEDG guidelines for hygienic design and easy cleaning. In addition, they feature the high IP protection required for each application and are made exclusively of detergent-proof materials. Consequently, the IP protection is not affected by long-term use in ambients with high air humidity or frequent cleaning with aggressive chemicals. In comparison to conventional automation solutions, these characteristics mark real progress in improved hygiene.

Modular valve programme
At entry level, decentralised automation based on intelligent valve systems starts with a process valve featuring integrated electrical feedback, simple optical feedback and an integrated pilot valve.

“The process valves require only minimum space and can therefore be easily installed in the pipeline system of the plant,” explains Sebastian Kundel, Segment Manager Hygienic Processing at Bürkert. “As they are made in extremely resistant materials, they are easy to clean and provide maximum availability thanks to excellent functional safety.” This excellent availability is mainly achieved by integration of the control air supply to the actuator chambers, which ensures that the spring chamber of the pneumatic actuator is supplied only with pure and clean control air. As a result, moisture, dust and contaminants in the ambient air cannot enter the actuator units. Similarly, there is no risk of fungal spores produced in the spring chamber being ejected into the ambient air at each switching process, which is a common problem with conventional actuator design.

Through a combination of control air inlet and release, a constant overpressure is maintained inside the housing, while a certain volume of air is regularly replaced. This ensures that no condensate can build up inside the housing. The modular structure of systems based on intelligent process valves enables them to be adapted according to each particular situation and application. With this in mind, such optimised solutions are always based on high-quality, tried-and-tested components with a long service life.

Company profile

Bürkert

For further information, visit: www.buerkert.com