Controlling Complex Processes In Hazardous Areas With A Modular Electrical And Pneumatic Automation System

By Werner Bennek, Segment Management Hygienic Processing, Bürkert Fluid Control Systems

Working with volatile liquids — as it is in every day business in the pharmaceutical and chemical industry — often implies potentially explosive atmospheres. Previously in such zone 1/21 environments control cabinets which combined electrical and pneumatic devices could not be used. Too high were the risks of corroding electrical parts which could subsequently cause an explosion. Today, new technologies permit the combination of electrical and pneumatic devices, even in zone 1/21 environments, achieving several cost-saving possibilities at the same time such as requiring less wiring, less planning, and less documentation.

Hybrid solutions combining electrical I/O-systems with optional pneumatic outputs are state of the art for installations in safe environments and in zone 2. "They are well accepted by OEMs and end users," says Werner Bennek, Segment Application Specialist at Bürkert Fluid Control Systems. Forming nodes, those electro-pneumatic systems connect numerous different electric signals and pneumatic outputs via a bus interface with higher automation systems. However, assembling electrical and pneumatic devices together in a single control cabinet for installation in explosion-hazard environments of zone 1 remains a challenge.