The DFPD series has a rack-and-pinion combination with constant torque over the entire swivel range in the double-acting version. The torque ranges from 10 to 480 Nm at an operating pressure of 5.5 bar. The single-acting version can be precisely configured in steps of 0.5 bar between 2 and 6 bar, depending on the operating pressure. The standard temperature range is -20 °C to +80 °C, but this Festo actuator can be configured both for low temperatures (-50 °C) and high temperatures (+150 °C).
For corrosive applications there is a version with epoxy coated housing and stainless steel shaft.
The torque is generated via a scotch yoke mechanism. Compared to a rack-and-pinion combination, the torque curve is not constant. The maximum torque is generated at an angle of rotation of 0°, which is advantageous for overcoming high break-loose torques of the butterfly valves. The torque ranges from 8 to 8000 Nm at an operating pressure of 5.5 bar.
The standard temperature range is -20 °C to +80 °C, but this Festo actuator can be configured both for low temperatures (-50 °C) and high temperatures (+150 °C).
As an option, the DAPS family offers manual override so that the position of the actuator can be changed manually with the handwheel when the supply pressure is switched off.
The quarter turn actuators comply with standard ISO 5211, which defines the interface between quarter turn actuators and fittings, and NAMUR VDI/VDE 3845 for direct mounting of sensor boxes, valve positioners and pilot valves.
Valve positioners enable simple and efficient control of the position of process valves actuated by pneumatic actuators. In general, a valve positioner converts an input signal into a corresponding setpoint position of the process valve. Depending on the type of input signal, pneumatic or electrical, a distinction is made between pneumatic or electropneumatic valve positioners. In order to use the valve positioners independently of the manufacturer, they are usually attached to pneumatic actuators according to the industrial standards VDI/VDE 3845 (quarter turn actuators) or VDI/VDE 3847 and IEC 60534-6 (linear actuators). If this is not possible, the valve positioner can also be mounted to the actuator with proprietary mounting kits to provide position feedback.
Sensor boxes are used for optical position indication with process valves which are actuated by pneumatic quarter turn actuators. Position feedback is provided by 2-wire or 3-wire technology. The switch types are divided into mechanical, inductive or magnetic switch types that can generate digital or analog signals. A special feature is that the NAMUR signal can also be connected to check further functions. The interface of the quarter turn actuators is standardized via the connection diagram VDI/VDE 3845.
Pilot valves are used for pilot control of quarter turn actuators. The medium flow is controlled electrically with the aid of a solenoid coil, which causes the flow to be released or shut off, thus changing the switching position of the quarter turn actuator. As a rule, different voltage options of the solenoid coil are available, which make it possible to take the local supply voltage into account.