BURKERT 20112962 Type 8640 is an AirLINE Quick modular pneumatic valve island block configured with four 3/2-way type C (normally closed) valves on an 11 mm station width grid. Engineered for direct control of process actuators and pneumatic machinery, this assembly integrates an aluminium AirLINE Quick base adapter featuring brass G 1/4 main air supply connections and brass push-in D6 working ports exiting through the bottom plate.

The unit operates at a nominal pressure range of 2.5 to 10 bar within an operating medium temperature window of 0 °C to +50 °C and an ambient temperature range of 0 °C to +55 °C. Configured as a revision 3 design with single electrical wiring, the assembly delivers an IP20 ingress protection rating in industrial control enclosures.

Valve Structure and Circuit Function

The manifold assembly houses compact solenoid-actuated directional control valves mounted on dedicated base segments. Each valve contains a pilot valve Type 6106 operating a main spool mechanism with NBR seat seals.

Pneumatic Port Identification

Connection Number	Port Identification	Function
1	P	Central pressure feed port (G 1/4)
2	A / OUT	Working outlet port (D6 push-in)
3	R	Exhaust vent port
4	B / OUT	Secondary working outlet port (when 4/2 configuration is used)

For circuit function C (3/2-way normally closed), pressure port 1 (P/NC) remains shut in the de-energised rest position, while working port 2 (A/OUT) communicates directly with exhaust port 3 (R/NO). Energising the pilot coil opens port 1 to port 2 while closing exhaust port 3.

Manual Override Operation

Each valve station incorporates an integrated mechanical manual override allowing manual actuation during setup or maintenance routines without electrical power.

To lock the manual override into active position, press the override element inward and turn it 90° clockwise until it hits the mechanical stop. In this position, the override remains mechanically latched and will not reset automatically. Before resuming automated electrical control, turn the manual override counter-clockwise back to the 0 position.

Operating Precaution

Only operate manual overrides when the electrical control supply is turned off. For standard electrical operation, verify that every manual override is in its unlatched zero position.

Technical Data

Technical Attribute	Specification Value
Product Type / Generation	Type 8640 / Revision 3
Order Code (Article Number)	20112962
Valve Configuration	4x 3/2-way valve function C (NC)
Station Grid Width	11 mm
Supply Port 1 (P)	G 1/4 female thread (AirLINE Quick brass fitting)
Working Ports 2 (A)	D6 push-in connectors (brass, bottom exit)
Operating Pressure Range	2.5 bar to 10.0 bar
Minimum Pressure Differential (Port 1 to Port 3)	2.0 bar
Fluid Temperature Range	0 °C to +50 °C
Ambient Operating Temperature	0 °C to +55 °C
Storage Temperature Limits	-40 °C to +55 °C
Medium Compatibility	Filtered compressed air (particle size ≤ 10 µm) or neutral gases (≤ 5 µm)
Seal Material	Nitrile butadiene rubber (NBR)
Mechanical Installation Type	AirLINE Quick aluminium interface plate
Internal Communication / Variant	Without internal bus (single-wire architecture)
Ingress Protection Rating	IP20

Mechanical Installation and Rail Mounting

Type 8640 blocks support standard DIN-rail mounting or direct surface mounting. The integrated clamping mechanism secures the block assembly onto standard profiles complying with EN 50022 (35 x 15 mm or 35 x 7.5 mm).

DIN Rail Mounting Steps

1. Hook the upper locating groove of the valve block over the upper lip of the standard rail.
2. Snap the lower clamping pieces into the lower edge of the standard rail.
3. Fasten the clamping screws securely to lock the island in place.
4. For direct wall mounting, secure the connection modules directly using M4 machine screws.

Tightening Torques for Port Connections and Fasteners

Connection / Assembly Point	Thread Size	Recommended Torque [Nm]	Maximum Torque [Nm]
Main Supply / Exhaust (P, R/S)	G 1/4	4.0 to 7.0 Nm	20.0 Nm
Auxiliary / Valve Ports	G 1/8	3.0 to 6.0 Nm	7.0 Nm
Valve to Base Module Fastening	Screw M2.5 / M3	0.6 ±0.1 Nm	—
Pilot Solenoid Coil Screw (Step 1)	Screw M2	0.1 ±0.05 Nm	—
Pilot Solenoid Coil Screw (Step 2)	Screw M2	0.2 ±0.05 Nm	—

If installation clearance requires an alternate cable routing, the pilot solenoid can be rotated 180° by loosening the M2 fastener, turning the coil body, and tightening it down in two successive increments of 0.1 Nm and 0.2 Nm.

Pneumatic Tubing Guidelines and Push-in Connectors

Connection lines must be pushed straight into the D6 push-in fittings until they reach the internal mechanical stop. Tubing must satisfy a minimum material hardness of 40 Shore D in compliance with DIN 53505 or ISO 868, with outer diameter tolerances according to DIN 73378 (permissible deviation ±0.1 mm from nominal size).

Tubing Preparation

Cut hose ends cleanly at a strict 90° right angle without burrs. Diagonal cuts or longitudinal scratches along the outer tubing circumference reduce claw retention and compromise seal integrity under pressure.

Minimum Tensile Holding Force per DIN ISO 14743:2020

Hose Outer Diameter (OD)	3 mm	4 mm (5/32")	6 mm (1/4")	8 mm (5/16")	10 mm (3/8")	12 mm (1/2")	14 mm	16 mm (5/8")
Polyamide (PA) Tubing	60 N	70 N	120 N	170 N	250 N	300 N	300 N	350 N
Polyurethane (PU) Tubing	25 N	50 N	100 N	150 N	200 N	200 N	250 N	300 N

For flexible polyurethane (PU) tubing lines, installing internal support sleeves (part ID 20099400) provides extra mechanical stability and seal reliability inside the push-in gripping collets.

Electrical Installation

Model 20112962 uses single-wired terminal terminations. Individual pilot coils accept standard DIN EN 175301-803 Form C connectors, such as Type 2516 cable plugs.

• Position the flat rubber seal evenly between the coil housing and the connector block.
• Tighten the cable plug mounting screw to a maximum torque of 0.3 Nm.
• Always connect the protective earth (PE) lead and verify electrical continuity.

Protective Conductor Parameter	Verification Value
Maximum Resistance	≤ 0.1 Ω
Test Voltage	12 V
Test Current	1 A

Continuous Operation Guideline

When valve islands remain in standby or non-energised states for extended periods, execute at least 1 to 2 switching cycles per day to maintain lubricant distribution across internal NBR seals and maintain spool responsiveness.

Troubleshooting Guide

Malfunction Symptom	Potential Root Cause	Corrective Action
Valves fail to switch	Absence of electrical operating voltage or supply voltage below tolerance	Check terminal connections; confirm supply matches voltage data on coil label.
	Manual override locked in active position	Return manual override detent to zero position.
	Operating feed pressure absent or below 2 bar	Verify primary air source; ensure pilot pressure exceeds 2.0 bar minimum differential.
Delayed valve response or continuous exhaust blow-off	Upstream line cross-section too small causing dynamic pressure drop	Expand supply lines or install local air accumulation reservoir.
	Block pressurised while valves were in energised state	De-energise all valve stations before charging main manifold pressure.
	Exhaust silencer blocked or undersized causing backpressure	Clean dirty silencer elements or replace with larger exhaust mufflers.
	Particle contamination inside pilot or main seat	Purge exhaust ports with pulsed compressed air or renew contaminated valve module.
Pneumatic leakage at manifold interfaces	Damaged, pinched, or missing O-rings between sub-base elements	Disassemble modules, inspect elastomer seals, lubricate, and replace damaged O-rings.
	Misaligned flat gasket between valve body and AirLINE adapter plate	Reseat gasket squarely and torque fixing screws to 0.6 ±0.1 Nm.

Disassembly and Disposal

1. Disconnect all electrical power and depressurise the entire pneumatic circuit before opening fittings.
2. To detach tubing from push-in connectors, depress the plastic release collar squarely inward and pull the hose outward.
3. Release DIN-rail mounting screws by loosening clamping screws approximately four full turns, then tilt the block upward.
4. Protect disconnected coil pins and pneumatic ports with clean dust caps during transit or storage.
5. Dispose of metallic aluminium/brass parts and electronic circuit components separately in compliance with local environmental waste management directives.