Bürkert Control Head for Decentralized Automation of Hygienic Process Valves

The control head Type 8681 is optimized for decentralised automation of hygienic process valves. Thanks to its universal adapter it can be combined with all normal commercial butterfly valves, ball valves, single and double seated valves. With a decentralised automation concept, the control head takes over all pneumatic actuation, feedback and diagnostic functions including fieldbus communication. The housing is easy to clean and features proven IP protection and chemically resistant materials for use in hygienic processing in food, beverage and pharmaceutical industries. Depending on the process valve type, up to 3 pneumatic actuator chambers can be controlled independently from each other. The switching speeds of both movement directions can be set separately. A built-in check valve prevents incorrect switching of process valve actuator chambers which could result from back-pressure. The process valve switching positions are detected by an inductive, analogue position sensor and reported to the PLC system. Up to 3 switching points can be adjusted automatically by a Teach-In function. Additionally a fourth switching position can be read in and fed back via an external inductive proximity switch. The coloured status display signals the particular process valve switching position or indicates a diagnostic function such as maintenance required status or fault conditions. The pilot valves are equipped with a manual override. If the device housing is closed, the patented magnetically encoded manual override tool can be used to open the process valve from the exterior. Bus communication is available with AS-interface, IO-Link or büS/CANopen.

Body

PA, PPO, VA, stainless steel

Cover

CR, EPDM

Configuration tool

Bürkert Communicator or PC service programme (according to device version)

Setting valve end position

Through automatic or manual teach function

Digital

IO-Link, Bürkert system bus (büS) (based on CANopen)

Valve spindle

0…80 mm

Output current

Max. 100 mA per feedback signal

Resolution

≤ 0.1 mm

Total error

± 0.5 mm when using a target for the dimensional drawing, (material 1.4021) and a piston rod

Control medium

Neutral gases, air, quality class according to ISO 8573 - 1

Dust content

Class 7 (< 40 µm particle size)

Particle density

Class 7 (< 10 mg/m3)

Pressure dew point

Class 3 (<- 20 °C)

Oil content

Class X (< 25 mg/m3)

Supply pressure

2.5…8 bar

HS Code

8481.80

• Burkert 8681
• Buerkert 8681
• Bürkert 8681
• Type 8681
• Burkert Type 8681