Burkert 20129075 Type 8640 is a modular valve island designed for pneumatic applications. This specific configuration is a 33mm 6-bank valve block featuring a 3/2-way valve function, a G 1/2 pressure port, and G 1/4 working ports located opposite the supply side. It operates reliably within a pressure range of 2 to 8 bar and is suitable for medium temperatures between 0 °C and 50 °C. The unit is designed for standard DIN-rail installation and utilizes a single wiring configuration, providing an IP20 protection rating.

The Type 8640 valve unit system is engineered to solve diverse and complex control problems through its systematic modular construction and combination of pneumatic and electrical interfaces. By assembling a row of pneumatic modules with different numbers of valves, multiple valve functionalities can be realized on a single valve unit. The bodies and connection modules are constructed from high-quality plastic (polyamide) and are easily assembled using built-in snap connectors.

Technical Data

• Operating Medium: Filtered compressed air (particle size max. 10 μm), preferably unlubricated (operation with lubricated air is possible); neutral gases (5 μm filtering).
• Seal Material: NBR
• Operating Pressure Range: 2 ... 8 bar (for this specific configuration)
• Ambient Temperature: 0 °C ... +55 °C
• Medium Temperature: 0 °C ... +50 °C

WARNING

Pilot pressure for the pneumatic control unit depends on the pressure of the flow medium; it must be between 2 ... 10 bar (at least 70% of operating pressure). The pressure difference between port 1 and 3 must be at least 2 bar. When temperatures are below 0 °C, operation is restricted to dried air.

Installation

Valve Block Installation

Standard rail installation (EN 50022 35 x 15 or 35 x 7.5):

1. Hook the valve block with the upper groove into the standard rail.
2. Snap the lower clamping pieces into the standard rail.
3. Tighten the screws on the clamping pieces.

Pneumatic Installation

DANGER

Risk of injury due to high pressure and escaping medium. Switch off the pressure before working on the device or system. Vent or drain the pipes.

• Installation position: Any, preferably with the solenoid actuator on top.
• Before connection: Check the hose lines for contamination and clean them. If necessary, install dirt traps upstream of the valve inlet (≤ 5 µm).
• Push the hose lines into the push-in connections of the solenoid valves until they come to a stop.
• Use PTFE tape or elastomer seal for sealing the threaded connection.
• Connect the supply and working lines to the valve block.

Electrical Installation

DANGER

Risk of injury due to electric shock. Switch off voltage before working on the device or system. Secure against reactivation.

• Screw on the cable plug, observing the maximum tightening torque of 0.3 Nm.
• Check that the seal is correctly fitted.
• Connect the protective conductor and check electrical continuity between the coil and housing.

Maintenance and Troubleshooting

Fault	Possible Cause	Remedy
Valves do not switch	No operating voltage or operating voltage too low	Check electrical connection. Ensure operating voltage according to type label.
	Manual override not in zero position	Bring manual override to zero position.
	Pressure supply insufficient or not available	Set up large-volume pressure supply. Minimum operating pressure ≥ 2 bar.
Valves switch with a delay or blow off at the exhaust ports	Pressure supply insufficient or not available	Set up large-volume pressure supply. Minimum operating pressure ≥ 2 bar.
	Valves are not in the home position (de-energised) during pressure build-up	Apply pressure to the valve block before the valves are switched.
	Insufficient ventilation of the exhaust air ducts due to too small or dirty silencers	Use suitably sized silencers or expansion vessels. Clean the dirty silencers.
	Impurities or foreign matter in the pilot or pneumatic valve	Apply pulsed pressure to the exhaust air ducts to blow out the impurities. Install a new pilot or pneumatic valve.
Leaky valve blocks	Missing or crushed O-rings between the modules	Identify leak or missing seals.
	Missing or incorrectly positioned flat seals between valve and base plate	Insert missing seals or replace damaged seals.