Pneumatics

Short definition

Pneumatics uses compressed air as an energy source for control and power transmission in industrial automation systems. It is characterized by simple installation, low maintenance and inherent explosion safety. Pneumatic systems include compressors, compressed air reservoirs, valves, cylinders and maintenance units. In membrane filtration systems, pneumatic actuators are used for fast switching valves, membrane pumps, sampling systems and safety functions, especially in hygienic or potentially explosive areas.

Functional principle

Compressors generate compressed air of typically 6-8 bar, which is stored in pressure vessels. Maintenance units (filter-regulator-oiler combinations) prepare the compressed air and ensure constant operating pressure. Pneumatic valves, usually designed as 3/2 or 5/2 directional control valves, control the direction and flow for cylinder actuation. Single-acting or double-acting cylinders convert compressed air into linear movement. Electrical control is via PLC-controlled solenoid valves. Proportional valves enable infinitely variable pressure and speed control. Pressure sensors and position switches provide feedback to the control system.

Areas of application

Pneumatics is particularly relevant in membrane filtration for hygienic applications, as compressed air is not critical in the event of leakage. Double diaphragm pumps (AODD) convey abrasive or shear-sensitive media gently. Pneumatic diaphragm valves ensure low dead space, sterilizable shut-off in pharmaceutical processes. Fast switching cycles during backwashing processes benefit from the high dynamics of pneumatic actuators.

Typical areas of application:

• AODD pumps (Air Operated Double Diaphragm) for concentrate delivery
• Pneumatic diaphragm valves in sterile processes
• Quick-acting backwash valves for crossflow systems
• Compressed air-driven sampling devices
• Emergency shut-off valves with spring-loaded function (fail-safe)

Summary

Pneumatics offers simplicity, safety and hygiene at moderate investment costs. It is ideal for applications with frequent switching operations and in sensitive production areas. For operators, it means low maintenance costs, high availability and easy integration into existing compressed air systems, especially in food and pharmaceutical filtration systems.