High-Precision Linear Actuator Provides Better Control

Festo's Pneumatic Linear Actuator, the DFPI

There are many applications in wastewater, electric power generation, bulk solids handling and other industry verticals where more precise control can mean better product quality or less energy usage. Many of these applications were originally installed with manual knife valves, gate valves and shut-off valves that could benefit from automatic control. Others were installed with electrical positioners or pneumatic positioners that require replacement and constant maintenance. With the increased interest in sustainability providing the impetus, many companies are in search of newer, simpler designs that cost less and require less maintenance.

Festo Corporation is well known for both high-precision motion control systems and truly inventive mechatronic research and development projects such as the robotic bird that flew at Hannover Messe earlier this year. It's also known for its lines of actuators used in process control applications.

Now the company has released a pneumatic linear actuator, the DFPI, which is designed for exactly those applications. According to Festo, its all-in-one design and patented technology make it ideal for controlling knife gate valves and shut-off valves with varying strokes.

The company notes that the device has been designed to be considerably simpler than an electrical actuator, and to provide higher forces than an equivalent electrical actuator at what the company say is a fraction of the price of alternative solutions.

Festo says that inlet gates to sewage plants, contact chamber flow control gate valves, penstock shut-off and flow control valves, knife gates for bulk solids silos, and other linear process valves are the applications the positioner was designed to serve.

 The device has an integrated displacement encoder and a linear potentiometric displacement sensor, valve manifold and positioner, and is designed for rough, outdoor, all-weather service with an extremely sturdy electrical connection and built-in heating element. The DFPI is offered with protection classes IP65, IP67 and IP69k. Explosion protection is per ATEX in accordance with EC directive 94/9/EC. The housing also has high corrosion resistance.

The device is offered with a built-in, self-initialization routine, which the company says makes commissioning quick and easy for integration in existing control architectures with a setpoint signal of 4-20 mA.
The device can be supplied with piston diameters from 100 mm (4 ins.) to 320 mm (13 ins.), and operates on filtered compressed air at 6 bar (90 psi). X lengths are standard up to 39 ins.; special designs above 39-in. stroke are available on request. The safety setting is "piston rod extending" or "retracting."

Festo says that because of the integral flow control functions, the back-and-forth movement speeds of the piston rod can be set separately or independently of each other, and sensing of the intermediate positions is optionally possible using exterior-mounted Festo position sensors.

The operating ambient temperature range is -5 °C to +50 °C (+23 °F to +122 °F), and its operating voltage is 24 VDC.

The company states that the accuracy of the linear actuator is ±2%.

For more information on this product visit or call +1-631-435-0800.