BURKERT Type 6518 (SKU 20000913) is a servo-assisted 3/2-way pneumatic solenoid valve designed for high flow-rate capacity and reduced power consumption. The valve width of 32 mm allows high flow rates up to 1300 l/min. These valves work without continuous air consumption and are used for the pneumatic control of double or single-acting actuators. The use of high-quality materials makes it possible to use these valves in the open air and under chemical atmospheres. The product line contains units with Ex-Approvals (Standard, Ex mb, Ex eb mb, and Ex ia variants) and NAMUR flange interfaces. With valve circuit functions C and D, safety level SIL2 can be achieved in accordance with IEC 61508, depending on the architecture of the safety device.

General Technical Data

Product properties	Details
Dimensions	Valve width 32 mm
Seal Material	NBR, PUR
Body Material	Polyamide, reinforced glass-fibre
Threaded bushing	Brass (stainless steel on request)
Manual override	Standard
Orifice	DN 8...DN 9
Pneumatic module	MP07
Circuit function	C and D
Thermal insulation class	Polyamide coil class B, Epoxy coil class H
Compressed air quality	ISO 8573-1:2010, class 7.4.4
Duty cycle	100 % continuous operation
Operating medium	Neutral medium (e.g. lubricated or oil-free compressed dry air)
Supply connection 1, 3, 5	Threaded G 1/4, NPT 1/4
Working port 2, 4	Threaded G 1/4, NPT 1/4
Degree of protection	IP65 with cable plug
Installation position	As required, preferably with actuator upright

Product Variants

Standard Variant

Type 6518 is a pilot operated 3/2-way valve (normally closed or open). The valves can be used individually or in blocks.

• Weight: 384 g (Coil size 32 mm)
• Switching time: Opening 20 ms, Closing 40 ms
• Operating voltage: 24 V DC, 24/110/230 V 50/60 Hz
• Medium temperature: -10 °C...+55 °C
• Ambient temperature: -25 °C...+55 °C

Ex mb and Ex eb mb Variant

Ex mb approval is achieved by fitting the valve with a corresponding push-over coil. The cable connection and the cable are permanently moulded to the coil.

Temperature Limits

The maximum medium temperature must never exceed the permitted temperature class (T4: +135 °C, T5: +100 °C, T6: +85 °C) minus 5 K.

• Weight: 600 g
• Switching time: Opening 20 ms, Closing 50 ms
• Operating voltage: 24/110/230 V UC
• Explosion protection: ATEX / IECEx (Ex mb IIC T* Gb, Ex mb IIIC T*** °C Db)

Ex ia Variant

The intrinsically-safe Type 6518 Ex ia valve consists of an intrinsically-safe pilot control and a pneumatic amplifier. The diaphragm-controlled valve seats work with very low friction, ensuring reliable switching of the valve, even after long shut-down periods. SKU 20000913 is an Ex ia variant.

Intrinsically Safe Operation

The valves are intended for operation at 24 V DC outputs via the intermediate switching of a corresponding intrinsically safe operating resource (isolating module or barrier).

• Weight: 580 g
• Switching time: Opening 75 ms, Closing 115 ms
• Minimum switching current: 29 mA
• Nominal resistance coil: 310 Ω
• Explosion protection: ATEX / IECEx (Ex ia IIC T6/T4 Gb, Ex ia IIIC T135 °C Db)

Circuit Functions

Symbol	Description
C	3/2-way solenoid valve. Servo-controlled. Normally closed.
D	3/2-way solenoid valve. Servo-controlled, with manual override. Normally open.

Dimensions

Standard variant 3/2-way valve, circuit function C and D (With plug form B or C)

(Dimensions in mm)

Product Design and Assembly

Block Assembly

Single modules or pre-assembled blocks can be ordered.

1. Connection module left
2. Base module 3-fold
3. Intermediate module: supply connections pierced for additional pressure supply or Connection module right: supply connections closed, thus enabling multiple operating pressures in a single block
4. Base module 2-fold
5. Connection module right
6. Supply connection: 3(R)
7. Supply connection: 1(P)
8. Supply connection: 5(S)
9. Cover plate for 3/2-way valve (to cover unused connections)

Valve Assembly

1. Pilot control
2. Manual override
3. Pilot pressure port
4. Working port

Installation Notes

Tightening Torques

Observe the following tightening torques when screwing in the port connections:

• G1/4 and NPT1/4: Recommended 4...7 Nm, Maximum 20 Nm
• M5 (auxiliary pilot air): Recommended 1...1.2 Nm, Maximum 3 Nm

Electrical Safety

If there is no protective conductor contact between the solenoid and the body, there is a risk of electric shock. Always connect the protective conductor and check electrical continuity between solenoid and body.