BURKERT 20131561 is a Type 8640 Generation Revision 3 (REV3) modular pneumatic valve island configured with an 11 mm station width, mixed 3/2-way valve functionality, and DIN rail mounting geometry. The unit integrates pneumatic base modules and pilot valves fabricated from high-strength polyamide, providing concentrated pilot actuation for process valves, pneumatic cylinders, and automation components in industrial control cabinets.

This specific article configuration features single electrical wiring per station without fieldbus modules, operating across an input pressure span of 2.5 bar to 10.0 bar. Pneumatic supply and exhaust headers utilize G 1/4 threaded ports, while working service lines utilize bottom-facing D6 (6 mm outer diameter) push-in tube couplings. The valve block provides an IP20 ingress rating under standard mounting and up to IP65 when enclosed in suitable control cabinets.

Technical Specifications and Operating Limits

Technical Parameter	Specification
Manufacturer Type	Type 8640
Article Number (Ident No.)	20131561
Hardware Generation	Revision 3 (REV3)
Modular Station Width	11 mm
Valve Population / Function	Mixed valve population (3/2-way functions)
Operating Pressure Range	2.5 bar to 10.0 bar (overpressure to atmospheric)
Operating Medium	Oil-free or lubricated compressed dry air, neutral gases
Compressed Air Quality	ISO 8573-1:2010, Class 7.4.4 (5 µm pre-filtration recommended)
Medium Temperature	0 °C to +50 °C
Ambient Operating Temperature	0 °C to +55 °C
Storage Temperature	-20 °C to +60 °C (device), -40 °C to +55 °C (transport)
Air Supply Ports 1(P), 3(R), 5(S)	G 1/4 female thread
Working Ports 2(A), 4(B)	Push-in connector for hose outer diameter 6 mm (D6)
Working Port Exit Location	Bottom of pneumatic sub-base module
Nominal Air Flow Rate ($Q_{Nn}$)	200 to 300 l/min (measured at +20 °C, 6 bar inlet, 1 bar $\Delta p$)
Operating Voltage	24 V DC (±10% tolerance, 1 Vss maximum residual ripple)
Nominal Coil Power	0.8 W per single valve station
Nominal Duty Cycle	100% continuous operation (ED)
Electrical Protection Class	III according to VDE 0580
Degree of Protection	IP20 (IP65 inside closed control cabinets)
Mounting Standard	Standard DIN rail EN 50022 (35 x 7.5 mm or 35 x 15 mm)
Body / Manifold Material	Polyamide (PA)
Sealing Materials	FKM, NBR, and PUR

Generation Revision 3 (REV3) Characteristics

Model 20131561 belongs to the BURKERT Type 8640 REV3 production series. REV3 hardware introduces specific mechanical and pneumatic enhancements over earlier REV1 and REV2 versions:

• Wavy Channel Geometry: The pneumatic working channel outlets on REV3 sub-bases feature a wavy (offset) layout rather than a parallel layout, optimizing port density and hose routing.
• Blue Hose Release Rings: The integrated D6 push-in connectors on REV3 modules utilize blue release collars, distinguishing them from the black rings on REV1/REV2 hardware.
• Optimized P Shut-Off: When equipped with internal P-shut-off mechanisms, flow degradation is limited to a maximum of 20%, compared to up to 50% on older generations.
• Standardised Valve Flange: Pilot valves for REV3 use standardised pneumatic mounting interfaces (such as FM20 and FM24), requiring matching REV3 replacement valve part numbers.

Flange Compatibility

Replacement pilot valves and sub-base modules must correspond to the REV3 generation. Standardised single valves for REV3 cannot be directly combined with older REV1/REV2 sub-bases without appropriate interface alignment.

Modular Assembly and Pneumatic Base Architecture

Type 8640 pneumatic assemblies are constructed from modular sub-base blocks held securely by built-in latch hooks:

Item	Assembly Element	Technical Description
1	Left pneumatic connection module	Houses primary supply port 1(P) and exhaust port 3(R) in G 1/4
2	Basic pneumatic modules	Multi-station blocks (e.g. 4-fold) accommodating 11 mm valves with D6 bottom ports
3	Right pneumatic connection module	Terminal supply unit or pressure zone separation module
4	Pilot valves	Type 6524 / 6525 flipper-actuated pneumatic seat valves

Assembly of pneumatic modules proceeds from the left connection module. Inter-module sealing relies on dual O-rings lightly greased prior to mechanical engagement. Lower latch hooks snap into the preceding module's grooves before rotating upward to lock the upper tab.

Integrated Pilot Valves and Circuit Functions

Model 20131561 utilizes an 11 mm mixed configuration incorporating BURKERT Type 6524 flipper pilot solenoid valves. Each pilot valve combines a Type 6144 flipper actuator with a high-response pneumatic seat valve body:

• Circuit Function C (CF C): 3/2-way valve, servo-controlled, normally closed (NC). Rest position blocks pressure port 1(P) while exhausting working port 2(A) through 3(R).
• Circuit Function D (CF D): 3/2-way valve, servo-controlled, normally open (NO). Rest position routes pressure port 1(P) directly to working port 2(B), keeping exhaust 3(R) shut.
• Double Valve Options: Double 3/2-way variants combine two independent functions on a single 11 mm slot, utilizing a 3-pin electrical interface and power reduction circuitry (2 x 0.8 W).
• Manual Override: Fitted as standard on each valve station. The manual override is depressed and rotated 90° clockwise until mechanical detent to actuate without electrical excitation. It does not reset automatically and must be returned to zero position for electrical cycling.

Dimensions and DIN Rail Installation

Model 20131561 is engineered for direct DIN-rail attachment inside cabinets. Any installation orientation is permissible, although mounting with solenoid coils pointing upright is recommended.

DIN Rail Mounting Steps

1. Hook the upper locating groove of the Type 8640 valve block onto the top lip of the EN 50022 standard rail (35 x 7.5 mm or 35 x 15 mm).
2. Snap the lower clamping pieces into the bottom lip of the rail.
3. Tighten the clamping screws securely to lock the island against vibration.
4. Disassembly is achieved by loosening the clamping screws by approximately 4 turns and tilting the assembly upward off the rail.

Pneumatic Hose Guidelines and Tensile Testing

Pneumatic working lines connect via D6 push-in couplings conforming to ISO 14743:2020. Strict piping preparation prevents leakage and line separation under pressure:

• Tubing Quality: Hoses must have a minimum hardness of 40 Shore D (per DIN 53505 / ISO 868) and outer diameter tolerances according to DIN 73378.
• Tubing Cut: Lines must be cut square at 90° without burrs, flattening, or surface scuffing.
• Engagement Depth: Insert the hose firmly past the internal release ring until it bottoms against the shoulder, engaging the gripping collet claws.

Hose Outer Diameter (OD)	Polyamide (PA) Tolerance	Polyurethane (PU) Tolerance	PA Min. Tensile Force	PU Min. Tensile Force
3 mm (1/8")	±0.08 mm	±0.10 mm	60 N	25 N
4 mm (5/32")	±0.08 mm	±0.10 mm	70 N	50 N
6 mm (1/4")	±0.08 mm	±0.10 mm	120 N	100 N
8 mm (5/16")	±0.08 mm	±0.10 mm	170 N	150 N
10 mm (3/8")	±0.08 mm	±0.15 mm	250 N	200 N
12 mm (1/2")	±0.10 mm	±0.15 mm	300 N	200 N

Tubing Retention

For 6 mm lines, a minimum tensile resistance of 120 N (for PA) and 100 N (for PU) must be maintained after insertion. When using softer PU tubing in vibrating applications, inserting internal support sleeves (Ident No. 20099400) provides extra mechanical stability.

Recommended Thread Tightening Torques

When threading pneumatic fittings into the Type 8640 supply or working ports, adhere to the recommended torque limits to prevent stress cracking in the polyamide manifolds:

Port Thread Size	Port Function	Recommended Torque	Maximum Permissible Torque
G 1/4 / NPT 1/4	Supply / Exhaust Ports 1(P), 3(R), 5(S)	4 to 7 Nm	20 Nm
G 1/8 / NPT 1/8	Working Ports 2(A), 4(B)	3 to 6 Nm	7 Nm

Manifold Protection

Never use the solenoid coil or valve body as a lever when tightening threaded pipe fittings. Threaded connections must be sealed using PTFE tape or compatible elastomer thread seals.

Diagnostic and Troubleshooting Procedures

Operational Malfunction	Potential Cause	Remedial Action
Valves fail to actuate	Operating voltage absent or below tolerance	Verify 24 V DC supply and check polarity on coil terminals.
	Manual override locked in actuated position	Turn manual override 90° counterclockwise back to zero position.
	Supply pressure insufficient (< 2.5 bar)	Confirm supply volume; verify main pressure is within 2.5 to 10.0 bar.
Delayed valve switching or blow-off at exhaust	Supply pressure below required operating limit	Ensure upstream regulators, filters, and lines provide adequate volume.
	Valve de-energized during initial pressure rise	Apply full pneumatic pressure before issuing electrical control signals.
	Exhaust restriction or clogged silencers	Clean contaminated silencer inserts or install larger exhaust headers.
	Contamination in pilot seat or core	Pulse-blow pneumatic exhaust channels or replace defective valve module.
External leakage between modules	O-ring seals pinched, damaged, or omitted	Disassemble block, inspect module O-rings, re-lubricate and reseat.
	Flange seals displaced under valve body	Ensure 3 O-rings/profile seals sit properly in valve base recesses.

Replacement Components and Spare Parts

Component Description	Generation / Interface	Article Number
Type 6524 3/2-way NC Valve (2.5-10 bar, 24 V DC)	REV3, 11 mm station width	20029918
Type 6524 3/2-way NO Valve (2.5-10 bar, 24 V DC)	REV3, 11 mm station width	20029919
Type 6525 5/2-way Valve (2.5-10 bar, 24 V DC)	REV3, 11 mm station width	20029920
Type 6524 2 x 3/2-way NC Valve (2.5-10 bar, 24 V DC)	REV3, 11 mm station width	186260
Pneumatic Supply Unit Right, G 1/4	Type 8640 REV3, 11 mm	20040351
Pneumatic Supply Unit Left, G 1/4	Type 8640 REV3, 11 mm	20040352
Pneumatic Base Unit 4-fold, D6, FM20	Type 8640 REV3, 11 mm	20040334
Set of Module Seals (MP16)	Type 8640 REV3, 11 mm (4 pcs)	20024339
Set of Valve Seals (FM20) for Type 6524 2x 3/2-way	Type 8640 REV3 (12 pcs)	20016305
Set of Valve Seals (FM24) for Type 6524	Type 8640 REV3 (12 pcs)	20024336
Blanking / Cover Plate for 11 mm Valve Slot	Solenoid valves Type 6524/6525	661092