BURKERT 20127515 (Type 6519) is a servo-assisted 5/2-way pneumatic solenoid valve engineered for process automation environments requiring intrinsic safety and extended thermal resistance. Built with a 1.4571 stainless steel main body, 1.4305 stainless steel pilot stage, and polyurethane (PUR) seals, article 20127515 accommodates medium temperatures from -30 °C to +80 °C and ambient temperatures from -30 °C to +60 °C. The valve operates without continuous air consumption, minimizing control air demand while actuating double-acting pneumatic drives or process valves.

The unit is configured in circuit function H/Z (normally open state: supply port 1 communicates with working port 2, working port 4 exhausts through port 5, and exhaust port 3 remains closed). It features a 9.0 mm main valve orifice and a 0.9 mm pilot control orifice, delivering a nominal air flow rate of 1980 l/min across an operating pressure envelope of 2.0 to 10.0 bar. Process connections comprise 1/4" NPT female threads with an FM02 flange interface and a 33 mm add-on dimension. Electrical actuation is achieved via an intrinsically safe coil rated at 11.1 V DC (Coil size 5), certified according to ATEX and IECEx standards for II 2 G Ex ia IIC T6 Gb and II 2 D Ex ia IIIC T135°C Db.

Technical Specifications

Technical Parameter	Specification Value	Standards / Notes
Burkert Type Family	Type 6519	Pilot-operated directional control valve
Burkert Article Number	20127515	Specific configured execution
Valve Construction	Piston spool with diaphragm pilot seat	Zero continuous control air consumption
Number of Ports / Positions	5 ports / 2 switching positions	Circuit function H/Z
Normal Position	Normally open	Port 1 connected to 2; port 4 to 5; port 3 closed
Main Valve Orifice (DN)	9.0 mm	Pilot orifice: 0.9 mm
Flow Rate QNn (Air)	1980 l/min	Measured at +20 °C, 6 bar inlet, 1 bar Δp
Working & Supply Connections	1/4" NPT female thread	Supply side flanged (FM02 interface)
Auxiliary Pilot Port	M5 thread	For external pilot air supply if applicable
Main Valve Body Material	Stainless steel 1.4571	High chemical and atmospheric resistance
Pilot Valve Body Material	Stainless steel 1.4305	Resistant to outdoor exposure
Sealing Material	PUR (Polyurethane), NBR, FKM	Suitable for extended temperature range
Operating Pressure Range	2.0 to 10.0 bar	Minimum differential pressure: 2.0 bar
Medium Temperature Range	-30 °C to +80 °C	Lubricated or non-lubricated compressed air
Ambient Temperature Range	-30 °C to +60 °C	Valid for coil size 5 Ex ia execution
Switching Times	Opening: 12 ms, Closing: 74 ms	Stainless steel 5/2-way response profile
Return Mechanism	Pneumatic spring + mechanical spring	Defined return into safe unpowered state
Manual Override	No manual override	Direct electrical pilot switching only
Add-On Dimension	33 mm	Valve pitch dimension
Ingress Protection Class	IP65	With correctly mounted Form A plug connector

Operating Principle and Circuit Function

Type 6519 utilizes a servo-assisted design combining an intrinsically safe electromagnetic pilot stage with a diaphragm-actuated main piston spool. The diaphragm-controlled valve seats operate with minimal internal friction, ensuring positive switching performance even after prolonged stationary periods or in cold outdoor operating environments.

In circuit function H, pressure applied at supply port 1 directs air to working port 2 while exhaust air from port 4 vents through exhaust port 5. When the solenoid is de-energized, the internal pneumatic and mechanical return springs immediately restore the valve to its normal position without relying on continuous pilot bleed.

Operating Compressed Air Quality

Compressed air must comply with ISO 8573-1:2010 Class 7.2.4. To prevent ice formation from expanding air inside the pilot and spool chambers, the pressure dew point must remain at least 10 K below the actual medium temperature.

For systems requiring external pilot pressure, pilot air must be connected to port 12 or 14 at a minimum of 70% of the working pressure applied to port 1, with an absolute minimum pilot pressure of 2.5 bar.

Intrinsic Safety and Electrical Data (Ex ia)

Article 20127515 incorporates an intrinsically safe solenoid coil (Coil size 5) configured for hazardous area duty. The coil interfaces via standard plug contacts conforming to DIN EN 175301-803 Form A. It is designed for operation from 24 V DC automation outputs via an associated intrinsically safe barrier or galvanic isolating module.

Electrical & Safety Parameter	Value at +20 °C	Value at +55 °C	Standard / Conditions
Rated Operating Voltage	11.1 V DC	11.1 V DC	Nominal coil rating
Minimum Terminal Voltage	9.0 V	10.4 V	Threshold for reliable pull-in
Minimum Switching Current	29 mA	29 mA	Threshold for reliable pull-in
Nominal Coil Resistance	310 Ω	360 Ω	Coil size 5 winding
Maximum Input Voltage (Ui)	35 V	—	Safety limit specification
Maximum Input Current (Ii)	0.9 A	—	Safety limit specification
Maximum Input Power (Pi)	1.1 W	—	Safety limit specification
Voltage Tolerance	±10%	±10%	Permissible supply deviation
Duty Cycle	100% ED	100% ED	Continuous operation rated
ATEX Explosion Protection	EPS 18 ATEX 1 088 X	II 2 G Ex ia IIC T6/T4 Gb; II 2 D Ex ia IIIC T135 °C Db
IECEx Explosion Protection	IECEx EPS 18.0038X	Ex ia IIC T6/T4 Gb; Ex ia IIIC T135 °C Db

Hazardous Location Operating Conditions

The valve must be operated strictly within the approved electrical safety thresholds (Ui ≤ 35 V, Ii ≤ 0.9 A, Pi ≤ 1.1 W) using an approved intrinsic safety barrier. The maximum medium temperature must never exceed the temperature rating of the applicable class minus 5 K (for T6: +85 °C - 5 K = +80 °C).

Materials and Environmental Compatibility

The wetted and environment-contacting components of article 20127515 are fabricated from high-grade austenitic stainless steel. The main valve body is manufactured from 1.4571 (316Ti) stainless steel, providing high durability against atmospheric moisture and chemical washdown. The pilot valve housing is constructed from 1.4305 stainless steel.

Internal seals are composed of polyurethane (PUR) combined with NBR and FKM. PUR provides wear resistance across high-cycle operations, while maintaining elastic sealing properties down to -30 °C. Chemical compatibility for specific industrial gases and ambient atmospheres can be evaluated using the online Bürkert resistApp chart.

Dimensions and Installation

The valve body dimensions for circuit function H in stainless steel extended temperature execution are standardized as follows:

Dimension Code	Component / Section	Value (mm)
A	Port centerline to reference face	53.5 mm
B	Valve body base width	107.0 mm
D	Ex ia pilot housing lateral offset	40.7 mm
E	Ex ia pilot housing depth	51.0 mm
H	Total valve assembly height (Ex ia)	186.6 mm
Pitch Dimension	Add-on module dimension 1	33.0 mm

Pneumatic Connections and Tightening Torques

All fluidic ports are indelibly numbered on the stainless steel valve body:

• Port 1: Supply pressure inlet (1/4" NPT female)
• Ports 2 and 4: Working lines to actuator chambers (1/4" NPT female, positioned opposite supply side)
• Ports 3 and 5: Exhaust vent outlets (1/4" NPT female)
• Ports 12 and 14: Auxiliary pilot pressure ports (M5 thread)

Connection / Fastener	Thread Size	Recommended Torque	Maximum Permissible Torque
Fluidic port fittings	1/4" NPT female	4 to 7 Nm	20 Nm
Auxiliary pilot port	M5	1.0 to 1.2 Nm	3 Nm
Body wall mounting screws	M4	2.0 Nm	5 Nm
Pilot stage fixing screws	Metric	1.0 Nm	1.5 Nm
Coil fastening nut	Metric (open-end wrench)	4.0 Nm	5 Nm
Cable plug retaining screw	M3 (DIN EN 175301-803)	0.8 Nm	1.0 Nm

Manifold Block Restriction

Type 6519 valves equipped with Ex ia intrinsically safe coils, terminal boxes, or NAMUR flange bodies are designed for direct installation and are not compatible with MP07 modular base rail manifolds.

Solenoid Orientation and Electrical Wiring

The solenoid coil can be rotated in 4 × 90° increments to accommodate constrained field installations. To reposition the coil, loosen the fastening nut with an open-end wrench, turn the coil to the desired angle, and retighten the nut to a maximum torque of 5 Nm. Never use the solenoid as a lever arm.

When securing the DIN EN 175301-803 Form A cable plug, ensure the elastomer profile gasket is seated between the plug housing and the coil header to preserve IP65 ingress protection. The protective conductor must be connected and verified for continuity (test resistance max 0.1 Ω at 12 V / 1 A).

Ordering Configuration and Compatible Accessories

Article 20127515 represents the 1/4" NPT stainless steel Ex ia configuration without manual override within the extended temperature Type 6519 family.

Article No.	Circuit Function	Orifice DN	Thread	Coil Resistance	Minimum Voltage	Pressure Range	Body Material
20127515	5/2-way (H/Z)	9.0 mm	1/4" NPT	310 Ω (11.1 V DC)	9.0 V DC	2.0 to 10.0 bar	Stainless steel 1.4571
20000888	5/2-way (H) manual	9.0 mm	G 1/4	310 Ω (11.1 V DC)	9.0 V DC	3.0 to 10.0 bar	Stainless steel 1.4571
20000889	5/2-way impulse (Z)	9.0 mm	G 1/4	310 Ω (11.1 V DC)	9.0 V DC	3.0 to 10.0 bar	Stainless steel 1.4571

Compatible Cable Plugs

• Type 2518 (Form A, DIN EN 175301-803): Standard industrial plug without circuit (0–250 V AC/DC, Article 314802); with LED indicator (12–24 V AC/DC, Article 314812); with LED and varistor (12–24 V AC/DC, Article 314820).
• Type 2513 (Form A, ATEX Cat. 3 GD): Certified cable plug with molded cable in lengths of 3 m (Article 260891), 5 m (Article 260892), or 12 m (Article 260893).