BURKERT 20073565 (Type 8640) is an 8-bank modular pneumatic valve block configured with a 33 mm station width, engineered to control neutral gases and filtered compressed air across automation applications. Operating within a pressure range of 2.00 to 8.00 bar and medium temperatures from 0.00 °C to +50.00 °C, this assembly integrates 3/2-way valve functionality into a pre-configured DIN-rail mountable block. Process pneumatic connections comprise a G 1/2 main supply port and G 1/4 working ports, providing centralized fluid distribution for eight independent pilot stages without requiring internal bus communication.

Each valve station in the block uses a pilot-operated assembly comprising a Type 6106 flipper pilot valve and a Type 5470 main body with elastomer diaphragm and seat seals. The module utilizes individual point-to-point electrical wiring (single wiring), resulting in an IP20 overall enclosure protection rating when installed in control cabinets.

Design and Structure

BURKERT Type 8640 valve blocks group modular sub-bases and individual solenoid valves into a rigid manifold. Individual stations consist of pilot stages mounted on pneumatic base plates that share internal supply channel 1 (P) and exhaust channel 3 (R).

Item	Designation
1	Pilot valve Type 6106
2	Exhaust port 3
3	Pressure port 1
4	Working port 4
5	Working port 2
6	Manual override
7	Cable plug Type 2506 / Type 2516

Manual Override

Each valve station is equipped with a mechanical manual override on the pilot body to permit manual actuation during commissioning and servicing. To engage the override, press the yellow button down and rotate it 90° clockwise until it hits the mechanical stop. The override locks in position and does not reset automatically.

Manual Override Safety

Operate the manual override only when the electrical power is disconnected. Prior to initiating electrical control, ensure the manual override is returned to the 0 (disengaged) position.

Connection Port Numbering

Pneumatic connections conform to standard industrial designations molded directly on the components:

Connection Number	Designation	Physical Thread (Article 20073565)
1	Pressure supply port (P)	G 1/2
2 and 4	Working ports (B and A)	G 1/4
3	Exhaust port (R)	G 1/2 (shared rail return)

Circuit Functions and Conversion

BURKERT 20073565 operates in 3/2-way circuit functions, providing directional flow control for single-acting pneumatic actuators or pilot circuits. The internal valve geometry supports standard circuit configurations:

• Circuit function C: 3/2-way valve, normally closed. In rest position, pressure port 1 (P) is blocked; working port 2 (A/OUT) vents through port 3 (R/NO).
• Circuit function D: 3/2-way valve, normally open. In rest position, pressure port 1 (P) feeds working port 2 (B/OUT); exhaust port 3 (R) is blocked.
• Circuit function G: 4/2-way valve standard configuration from which 3/2-way operations can be derived.

To convert a 4/2-way basic valve body to a 3/2-way function, install an airtight threaded stopper into port 2 or port 4 as indicated below:

Port 2	Port 4	Resulting Circuit Function
Closed with stopper	Open	Function C (3/2-way, normally closed)
Open	Closed with stopper	Function D (3/2-way, normally open)

Technical Specifications

Specification	Parameter Value
Type	8640
Article Number	20073565
Station Configuration	8-bank (8 valve positions)
Station Width (Add-on Dimension)	33 mm
Valve Function	3/2-way
Pressure Port 1 (P)	G 1/2
Working Ports 2 (B) / 4 (A)	G 1/4
Nominal Operating Pressure Range	2.00 bar to 8.00 bar
Pilot Pressure Requirement	2.00 to 10.00 bar (must be at least 70% of operating pressure)
Minimum Differential Pressure (Ports 1 to 3)	2.00 bar
Medium Temperature Range	0.00 °C to +50.00 °C
Ambient Operating Temperature	0.00 °C to +55.00 °C
Fluid Compatibility	Filtered compressed air (particle size max. 10 µm), neutral gases (5 µm filtration)
Lubrication Condition	Preferably unlubricated (operation with lubricated air permissible)
Seal Material	NBR (Nitrile butadiene rubber)
Mounting Base Style	Standard rail installation (DIN rail EN 50022)
Communication / Fieldbus	None (single direct wiring)
Digital Input Count	0 PCE
Intermediate Supply Modules	0 PCE
Manual / Automatic Electrical Switching	No
Integrated Check Valves in 3 (R) / 5 (S)	No
Pneumatic HotSwap in 1 (P)	No
Enclosure Protection Class	IP20 (with single wiring connectors)
Storage Temperature	-40.00 °C to +55.00 °C

Mechanical and Base Module Installation

BURKERT 20073565 is pre-assembled as an 8-station valve manifold using modular pneumatic sub-bases held together with integrated latch hooks and tabs.

Sub-Base Block Assembly Sequence

1. Installation begins from the left connection module (Item 1).
2. Inspect each adjoining base module to ensure both O-rings are present and properly seated in their sealing channels.
3. Lightly lubricate all elastomer O-rings with grease or oil before interlocking modules.
4. Hook the lower latch hooks (Item 3) of the new module into the lower latch tabs (Item 2) of the adjacent module.
5. Press the module upward and engage the upper latch hook until it snaps firmly into place.
6. Prior to mounting individual valves, insert 3 O-rings into the rear recess of each valve body.
7. Secure each Type 5470 valve to the sub-base using two screws tightened to 0.6 ±0.1 Nm.

Seal Integrity

Crushed, pinched, or missing O-rings between base blocks or on the valve mounting face will result in pressure loss and leaky manifolds. Never tighten mounting screws if seals are displaced.

Standard DIN Rail Mounting

The complete block secures directly onto a standard DIN mounting rail complying with EN 50022 (35 x 15 mm or 35 x 7.5 mm):

1. Hook the upper locating groove of the valve block over the top edge of the standard rail.
2. Swivel the block downward and snap the lower clamping pieces over the lower edge of the rail.
3. Tighten the clamping screws located on the clamping feet until the assembly is rigidly fixed.
4. Alternatively, wall mounting is supported via M4 screws inserted directly through designated module holes.

Solenoid Coil Orientation

If the electrical connector clearance requires adjustment, the solenoid pilot coil can be rotated 180°:

1. Loosen the M2 mounting screw and carefully lift the coil from the valve body.
2. Rotate the coil 180°, reseat it squarely onto the valve body, and engage the screws.
3. Tighten the M2 screw incrementally: first stage to 0.1 ±0.05 Nm, followed by final tightening to 0.2 ±0.05 Nm.

Pneumatic and Electrical Installation

Pneumatic Guidelines

Pneumatic supply lines must be blown clean before attachment. If line contamination is suspected, install a 5 µm filter immediately upstream of port 1 (P).

Port Thread Size	Function / Marking	Recommended Torque [Nm]	Maximum Torque [Nm]
G 1/4	Supply P, Exhaust R/S	4 to 7	20
G 1/8	Working lines A/B, Pilot feeds	3 to 6	7

• Minimum hose hardness must be 40 Shore D in accordance with DIN 53505 / ISO 868.
• Hose outer diameter must strictly adhere to DIN 73378 (permissible tolerance ±0.1 mm from nominal size).
• Hoses must be cut square, burr-free, and inserted fully past the internal grab rings into push-in fittings.

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

Flexible Hose Retention

When utilizing soft polyurethane (PU) tubing under high working pressures, insert support sleeves (ID 20099400) inside the hose end to maximize radial retention and eliminate pull-out risks.

Electrical Installation

Each solenoid coil connects via individual industrial form C cable plugs (such as Type 2516 / DIN EN 175301-803 Form C) fastened with a central screw.

• Voltage tolerance: ±10%.
• Cable plug fastening torque: Max. 0.3 Nm on the plug screw; up to 1.0 Nm on the coil collar.
• Ensure the flat profile gasket is compressed evenly between the coil face and plug body.
• Always connect the protective earth conductor (PE) to ensure electrical continuity across metal valve structures.

Parameter	Protective Conductor Test Specification
Maximum Earth Resistance	0.1 Ω
Test Voltage	12 V
Test Current	1 A

Commissioning, Maintenance, and Troubleshooting

Prior to pressurization, verify that all pneumatic fittings and M4/M2 fasteners are torqued to specification. Supply voltage must match the coil rating, and the manual override screws must be unlocked.

Diagnostic Matrix

Fault Condition	Probable Cause	Corrective Action
Valve fails to switch	Operating voltage absent or below tolerance	Check wiring terminals; verify supply voltage matches type label within ±10%.
	Manual override locked in non-zero position	Rotate manual override 90° counter-clockwise to zero position.
	Supply pressure insufficient (< 2 bar)	Increase upstream volume and pressure; ensure minimum supply pressure is ≥ 2.0 bar.
Delayed switching or continuous venting at exhaust 3	Operating pressure below pilot threshold	Establish large-volume air reservoir; ensure operating pressure is ≥ 2.0 bar.
	Valves energized prior to pneumatic pressure build-up	Apply full pneumatic pressure to port 1 before applying electrical switching signals.
	Exhaust port backpressure due to clogged silencer	Clean clogged silencers, replace with high-flow mufflers, or expand exhaust lines.
	Contaminants or debris inside pilot or main chamber	Blow compressed air in reverse pulses through exhaust ducts, or replace affected pilot/valve.
External air leakage between modules	Missing, pinched, or damaged inter-module O-rings	Disassemble base block and replace damaged O-rings between sub-bases.
External leakage under valve body	Damaged or misaligned flat seat seals	Remove valve, verify correct gasket seating, and retorque screws to 0.6 Nm.

Disassembly and Storage

Before disassembling the valve manifold, isolate the pneumatic pressure supply, vent all lines, and disconnect all electrical power sources.

1. Valve block removal: Loosen the rail clamping screws approximately 4 turns, pivot the block forward, and lift it clear of the DIN rail.
2. Module separation: Insert a flat screwdriver into the release groove on the front face of the sub-base, disengage the upper latch hook, and pull the module laterally away.
3. Tubing removal: Depress the release ring of the push-in fitting squarely toward the fitting body while pulling the pneumatic tubing outward.
4. Storage: Store the unit in a dry, dust-free environment at temperatures between -40.00 °C and +55.00 °C with protective caps installed on all pneumatic ports.