Valve actuators has integral control

Paul Boughton

Festo is launching a series of highly integrated pneumatic drive products that are suitable for wastewater treatment plants or systems used in the chemical industry.

The new DFP series includes a completely self-contained linear drive unit, and a quarter-turn actuator that uses a rack-and-pinion design.

The DFPI series linear drives feature a displacement encoder, valve manifold and position controller - all contained within the same housing. This high level of functional integration transforms the actuator technology into a complete, sturdy system that is suitable for use outdoors and in cold, dusty or hazardous environments.

DFPI linear drives are particularly suitable for use with gate valves in wastewater treatment plants to accurately regulate the flow of digested sludge into digester tanks. In applications such as this, the DFPI drives offer numerous advantages over conventional modular systems, including much more compact dimensions, good explosion protection characteristics and high corrosion resistance. Furthermore, the drives can be controlled via a PLC and are therefore easy to integrate into existing control architectures. And for northerly climates, they can be fitted with a heating element to ensure effective flow control even in low ambient temperatures.

Festo's DFPB pneumatic quarter-turn actuator is intended primarily for automated control of the flow of biogas created in digester tanks, though it is equally suitable for process control applications in areas as diverse as the pharmaceutical industry and coffee-roasting plants. When combined with an electro-pneumatic position controller, the actuator can also used for high-precision positioning applications, such as the control of ball-and-plug, shut-off and butterfly valves. The actuator uses rack-and-pinion technology to convert the linear movement of the piston into rotation of the shaft.

DFPB actuators offer a host of advantages for demanding applications. They exhibit a constant-torque characteristic across their entire rotation angle range of 90 degrees thanks to their rack-and-pinion design. And they are also extremely compact, with single-acting and double-acting actuators utilising the same housing. A new pressure-dependent lip seal minimises frictional losses and ensures a longer service life. The innovative housing concept also means that the actuator can be mounted on both right-closing and left-closing process valves.

DFPI series linear drives

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