BURKERT 20026069 (Type 8650 AirLINE Ex) is a modular electropneumatic automation system engineered for discrete process control in Zone 1/21 hazardous areas. Configured under Generation Revision 2 (REV2), this assembly features 24 pneumatic valve stations across an 11 mm width grid, equipped with 24 individual 5/2-way Type 6525 Ex i solenoid valves with circuit function H. The unit operates in combination with the Siemens SIMATIC ET 200iSP decentralized I/O peripheral system, establishing direct digital and pneumatic process control inside certified field enclosures.

Pneumatic supply and exhaust lines interface through G 3/8 threaded ports on the right and left supply slices, while working ports 2 and 4 utilize D6 push-in couplings oriented at the bottom of each pneumatic module. The system integrates pneumatic HotSwap in the P-channel (1) to permit live pilot valve exchange under system pressure, alongside integrated non-return check valves in the exhaust channels R (3) and S (5) to suppress backpressure-induced actuator movement.

Technical Specifications

Specification Parameter	Value / Detail
Model / SKU	20026069
System Series	Type 8650 AirLINE Ex (Revision 2 / REV2)
Number of Valve Stations	24 stations (24-bank)
Width per Station	11 mm
Valve Circuit Function	24x 5/2-way, circuit function H (Type 6525 Ex i)
Nominal Pressure Range	2.5 bar to 7.0 bar
Nominal Flow Rate QNn (Air)	Approx. 225 l/min (300 l/min baseline reduced by 25% via HotSwap)
Supply Port P (1)	G 3/8
Exhaust Ports R (3), S (5)	G 3/8
Working Connection (2, 4)	Plug-in connector D6 (bottom of pneumatic base module)
Intermediate Feed Quantity	0 PCE (block design without intermediate slice)
Pressure Sensor Quantity	0 (without integrated pressure sensor)
Medium / Operating Fluid	Lubricated or non-lubricated compressed air (ISO 8573-1:2010, Class 7.4.4)
Ambient & Medium Temperature	0 °C to +50 °C
Storage Temperature	-40 °C to +70 °C
Permissible Relative Humidity	5% to 95%, non-condensing
Nominal Operating Mode	100% continuous duty cycle
Nominal Power per Valve	0.3 W (max. 30 mA current per valve)
System Ingress Protection	IP30 (DIN EN 60529)
Safety Enclosure Requirement	Ex e control cabinet with min. IP54 protection
Explosion Protection Ratings	ATEX: II 2G Ex eb ib IIC T4 Gb (BVS 21 ATEX E 013 X) IECEx: Ex eb ib IIC T4 Gb (IECEx BVS 21.0013X) CCC: GB/T 3836 series certified

System Architecture and Module Design

Type 8650 REV2 combines Siemens SIMATIC ET 200iSP electrical subrack modules with Bürkert pneumatic valve base blocks on an S7 standard mounting rail. The assembly consists of terminal modules, electronic output modules (4DO 11 mm), pneumatic base segments, right and left supply slices, and Type 6525 Ex i pilot valves.

Element Position	Component Description	Interface Specifications
1	Supply slice, left	G 3/8 (P/1, R/3, S/5), G 1/8 (X), integrated pressure gauge, 0 W
2	Valve slice (44 mm modular block)	4x 11 mm valve slots, D6 plug-in working couplings (ports 2, 4)
3	Electronic module (4DO 11 mm)	4 discrete output channels, power consumption max. 3.2 W per 4 DO
4	Supply slice, right	G 3/8 (P/1, R/3, S/5), G 1/8 (X), integrated pressure gauge, 0 W

Communication and Power Architecture

All electrical power and communication bus functions are routed through the Siemens SIMATIC ET 200iSP backplane. Terminal modules establish contact automatically upon attachment. Operating voltage is supplied via the ET 200iSP intrinsically safe Power Supply module, supporting remote process integration over PROFIBUS DP-is or PROFINET IO.

Pneumatic Configuration and HotSwap Functions

Article 20026069 incorporates pneumatic HotSwap in line 1 (P) and integrated check valves in channels 3 (R) and 5 (S). These mechanisms ensure process continuity and operational safety in high-density process skids.

Feature Option	Physical Effect	Functional Restriction
P HotSwap (Pneumatic Shut-Off)	Auto-seals P supply when pilot valve is dismounted under pressure	Nominal flow reduced by ~25%; max. 4 valves removed concurrently
R/S Check Valves	Blocks backpressure transients entering inactive cylinder exhaust ports	Not suitable for vacuum or low-pressure supplies (<2.5 bar)
P Partition Plugs (Optional)	Divides P gallery into segregated pressure or media segments	Not installed on this 24-bank single-pressure configuration

HotSwap Safety Limits

When replacing pilot valves under supply pressure, remove no more than 4 valves at any one time. Dismounting more than 4 stations simultaneously causes a steep drop in system feed pressure. HotSwap check valves are not rated for vacuum service.

Pilot Valves (Type 6525 Ex i, 11 mm)

The pneumatic switching functionality of 20026069 is executed by Type 6525 Ex i pilot valves. Each valve consists of an intrinsically safe solenoid pilot valve paired with a pneumatic seat valve body.

Parameter	Value (Type 6525 Ex i, 11 mm Width)
Circuit Function	Function H (5/2-way, servo-controlled, bistable resting mode)
Nominal Diameter	DN 4 mm
Body Material	Polyamide (PA)
Seal Material	Nitrile butadiene rubber (NBR)
Manual Override	Standard rotary switch
Switching Time (ISO 12238)	Opening: 15 ms / Closing: 20 ms
Operating Power	0.3 W per valve
Mounting Fasteners	2 screws M2 x 20 (tightening torque 0.2 Nm)
Revision Compatibility	REV2 single-valve flange profile (not backwards interchangeable with REV1 bases)

Explosion Protection and Installation Requirements

Type 8650 REV2 valve island holds explosion protection certifications under ATEX and IECEx, classified under II 2G Ex eb ib IIC T4 Gb. The terminal bases utilize increased safety (Ex e), while the electronic modules and pilot valves utilize intrinsic safety (Ex i).

Installation Requirements for Enclosures

To satisfy certification requirements for Zone 1 or Zone 21, mount the valve island inside a certified Ex e control cabinet that provides at least IP54 ingress protection. Ensure the cabinet dimensions and heat dissipation capacity prevent internal temperatures from exceeding +50 °C during full-duty operation.

Grounding connections on the Siemens S7 standard rail must be tied directly to the equipotential bonding system of the hazardous installation. Electrostatic discharges pose ignition risks; clean plastic external surfaces only with a damp, lint-free cloth.

Mechanical Dimensions and Mounting

Mechanical Interface	Tool Type and Size	Tightening Torque
DIN Rail Clamping Bolts	Torx T25 hex key	1.5 Nm
Module Tie Rods (Inter-block fastening)	3 mm Hex socket	0.7 Nm
Valve Screws (11 mm station width)	Size 0 Phillips screwdriver	0.2 Nm
Supply Port Thread (P, R, S)	G 3/8 pipe fittings	Max. 20 Nm
Auxiliary Pilot Air Port (X)	G 1/8 pipe fittings	Max. 8 Nm
Filter Cover Plate Screws	Torx T10 key	0.7 Nm

Replacement Valves and Spare Components

Component Description	Model / Order ID	Notes / Functional Role
Replacement Valve Type 6525 Ex i (5/2-way)	20028761	REV2 replacement pilot valve, 2.5 to 7 bar, manual override
4-fold Pneumatic Base Module (11 mm, D6)	20014279	REV2 modular base, HotSwap shut-off, integrated check valves
Electronic Base Module (4DO, 11 mm)	171941	Deep grey REV2 terminal module for 4 discrete valve outputs
Left Supply Slice (G 3/8, with manometer)	20014283	Primary pneumatic supply and exhaust unit, left boundary
Right Supply Slice (G 3/8, with manometer)	20014285	Primary pneumatic supply and exhaust unit, right boundary
Spare Module Seals MP17	20016310	4-piece sealing set for inter-module boundaries
Spare Valve Seals FM20	20016305	12-piece O-ring set for 11 mm valve seating faces
Unused Valve Slot Cover Plate (11 mm)	661092	Seals unused pneumatic slots on REV2 base modules