BURKERT 20149423 (Type 8640) is a revision 3 modular pneumatic valve island configured with a 16.5 mm station pitch, a G 3/8 pneumatic supply port, and bottom-facing D8 push-in working connections. Built around Type 5470 pilot-controlled directional valves and Type 6106 flipper pilot stages, this assembly provides automated pilot control for neutral media and filtered compressed air. The unit incorporates a collective socket electrical interface for integrated multichannel actuation, DIN-rail mounting hardware, and an overall enclosure rating of IP20.

Technical Attributes and Configuration Parameters

The table below outlines the core product specifications and operational constraints for article 20149423:

Specification Parameter	Value / Characteristic
Article Number (SKU)	20149423
Product Type	Type 8640
Hardware Generation	Revision 3
Station Pitch (Width per Station)	16.5 mm
Valve Configuration	Mixed valve population (3/2-way operation)
Pneumatic Supply Connection (Port 1 / P)	G 3/8 internal thread
Working Connection Size (Ports 2 / B and 4 / A)	D8 push-in fittings
Working Connection Exit Orientation	Bottom (pneumatic base module)
Nominal Operating Pressure Range	2.0 bar to 10.0 bar
Medium Operating Temperature Range	0.0 °C to +50.0 °C
Permissible Ambient Temperature Range	0.0 °C to +55.0 °C
Digital Input Channels	0 PCE
Integrated Pressure Sensor	None (0)
Integrated Exhaust Check Valves	Not present (Ports 3/R and 5/S)
Pneumatic HotSwap Function	Not present (Port 1/P)
Communication / Wiring Module	Collective socket module
Internal Control Bus	Bürkert proprietary
Ingress Protection Rating	IP20 (with appropriate electrical mating connection)
Mechanical Installation Method	Standard DIN rail mounting

Valve Architecture and Mechanical Structure

Individual valve slices in the Type 8640 island utilize Type 5470 directional bodies coupled to Type 6106 electromagnetic pilot valves. Sealing within the main stage is handled by NBR diaphragm and seat seals mounted between connection plates.

Item	Designation
1	Pilot valve Type 6106
2	Exhaust port 3 (R)
3	Pressure port 1 (P)
4	Working port 4 (A)
5	Working port 2 (B)
6	Manual override mechanism
7	Cable plug interface (Type 2506 / 2516 reference)

Pneumatic fluid channels are identified numerically across the sub-base and valve modules: port 1 serves as the common pressure supply, ports 2 and 4 provide the working outputs to pneumatic actuators, and port 3 serves as the pilot and main stage exhaust.

Manual Override and Circuit Configuration

Each valve station is equipped with a mechanical manual override on the valve body. This mechanism allows manual testing and commissioning without electrical control signals.

Operating Manual Override

Operate the manual override only when the electrical power supply is switched off. To actuate, depress the manual override button and rotate it 90° clockwise until it hits the mechanical stop. In this position, the override is locked in the operated state and will not reset automatically. To resume normal electrical operation, turn the override back 90° counter-clockwise to zero position.

Directional Circuit Functions and Conversion

The valve island supports multiple standard pneumatic circuit configurations:

• Circuit Function C: 3/2-way valve, normally closed (NC). In rest position, pressure port 1 (P) is blocked; working port 2 (A) exhausts to port 3 (R).
• Circuit Function D: 3/2-way valve, normally open (NO). In rest position, pressure port 1 (P) routes flow to working port 2 (B); exhaust port 3 (R) is closed.
• Circuit Function G: 4/2-way valve. In rest position, supply port 1 connects to port 2 (A), and port 4 (B) exhausts to port 3 (R).

A 4/2-way valve station can be converted to specific 3/2-way operations by sealing one of the working outlet ports with an airtight stopper plug:

Port 2 (B)	Port 4 (A)	Resulting Circuit Function
Closed with plug	Open	Function C (Normally Closed)
Open	Closed with plug	Function D (Normally Open)

Modular Assembly and Base Mounting

Valve island Type 8640 utilizes modular pneumatic base rails that interconnect laterally. Assembly begins from the left connection module, snapping intermediate base segments together using upper and lower latching hooks.

Item	Designation
1	Left connection module
2	Latch tab
3	Latch hook
4	Base modules (3-fold)
5	Right connection module
6	Base modules (2-fold)
7	Exhaust channel 3 (R)
8	Supply channel 1 (P)
9	Inter-module O-rings

Before sliding modular blocks together, ensure that two elastomer O-rings are seated between adjacent channel faces and lightly lubricate them with compatible grease. Engage the lower latch hook into the mating groove, pivot the module upwards, and lock the upper latch hook into engagement.

Sealing Integrity on Valve Bases

Each valve requires three O-rings inserted into the recesses on the rear body face prior to fastening. Crushed, pinched, or missing profile seals cause external leakage and internal pressure cross-talk. Fasten each valve body onto the base module using two screws tightened to a recommended torque of 0.6 Nm ± 0.1 Nm.

DIN Rail and Mechanical Installation

The complete block installs directly onto standard symmetrical DIN rails conforming to EN 50022 (dimensions 35 x 15 mm or 35 x 7.5 mm):

1. Hook the upper locating groove of the valve block mounting feet onto the top edge of the DIN rail.
2. Snap the lower spring clamping pieces over the bottom edge of the rail.
3. Tighten the clamping piece locking screws securely.
4. Alternatively, wall-mount the assembly by driving M4 fastening screws through the mounting tabs on the connection modules.

Fastening Torques for Threaded Ports

When connecting pneumatic piping into threaded ports, adhere to the following torque limits:

Port Thread Size	Port Marking / Function	Recommended Torque [Nm]	Maximum Torque [Nm]
G 1/4 / NPT 1/4	Supply 1 (P), Exhaust 3 (R/S)	4 to 7	20
G 1/8 / NPT 1/8	Supply 1 (P), Exhaust 3 (R/S), Outlets 2 (B) / 4 (A)	3 to 6	7

Pneumatic Piping and Push-in Connector Guidelines

Article 20149423 provides bottom-facing D8 push-in connections on the pneumatic base. Reliable sealing and hose retention require strict compliance with dimensional and mechanical specifications.

Hose Line Requirements

• Tube material: Polyamide (PA) or Polyurethane (PU).
• Hardness: Minimum 40 Shore D according to DIN 53505 or ISO 868.
• Outer diameter tolerances according to DIN 73378 (permissible deviation ± 0.1 mm from nominal dimension).
• Tubing must be cut square at 90°, free of burrs, and free of scratches or ovality on the sealing surface.

To ensure proper hose retention under pressure, push-in fittings must meet the minimum tensile pull-out forces defined by DIN ISO 14743:2020:

Hose Outer Diameter (OD)	Polyamide (PA) Minimum Tensile Force	Polyurethane (PU) Minimum Tensile Force
3 mm (1/8 in / 3.17 mm)	60 N	25 N
4 mm (5/32 in / 4.00 mm)	70 N	50 N
6 mm (1/4 in / 6.35 mm)	120 N	100 N
8 mm (5/16 in / 8.00 mm)	170 N	150 N
10 mm (3/8 in / 9.52 mm)	250 N	200 N
12 mm (1/2 in / 12.7 mm)	300 N	200 N
14 mm	300 N	250 N
16 mm (5/8 in / 16.0 mm)	350 N	300 N

Tubing Retention with Softer Polymers

When using softer polyurethane (PU) tubing, internal support sleeves (Burkert ID 20099400) can be inserted into the tube core to eliminate wall collapse under clamping teeth and guarantee joint seal integrity.

Electrical Operation and Electrostatic Safety

Electrical signals are distributed to individual valve coils via the collective socket interface. All electronic components within the module are susceptible to electrostatic discharge (ESD).

Electrostatic Precautions

Observe ESD handling precautions compliant with EN 61340-5-1. Never touch internal terminal pins or circuit boards while electrical supply voltage is active.

Reliability During Continuous Operation

When operating in continuous duty applications with long static periods, perform at least 1 to 2 switching cycles per day during idle phases to maintain mechanical responsiveness and valve seal compliance.

Operational Troubleshooting

Fault Observed	Probable Cause	Corrective Action
Valves fail to switch	Missing or insufficient control voltage	Verify wiring connections; confirm supply voltage matches collective socket rating.
	Manual override not in home position	Rotate manual override back counter-clockwise to zero position.
	Insufficient or absent pneumatic supply	Establish high-volume pressure feed; verify system operating pressure is ≥ 2.0 bar.
Delayed switching or blow-off at exhaust ports	Air supply capacity insufficient	Ensure upstream regulator, filter, and shutoff valves provide adequate volume; maintain pressure ≥ 2.0 bar.
	Valves energized prior to pneumatic pressurization	Apply pneumatic line pressure to the valve island before initiating electrical switching cycles.
	Excessive back-pressure on exhaust ducts	Inspect exhaust silencers for clogging; clean silencer elements or replace with larger volume silencers.
	Particulate contamination inside pilot or main stage	Apply brief pressure pulses through exhaust ducts to blow out foreign matter, or replace the affected valve.
Leakage across valve block joints	Missing or pinched O-rings between base modules	Disassemble sub-blocks, inspect O-ring seals, and replace missing or crushed elastomer rings.
	Misaligned or damaged flat seals beneath valve slice	Loosen mounting screws, realign flat profile seals, and retorque valve body screws to 0.6 Nm.