Description
NAMUR ATEX Ex d 3/2 Universal Solenoid Valve – Rotex 30318-5
The Rotex 30318-5 is an ATEX Ex d explosion-proof NAMUR solenoid valve designed for direct mounting onto spring-return pneumatic actuators in hazardous-area applications.
Featuring 3/2 way universal, direct-acting operation, the valve operates from 0 to 10 Bar without requiring a minimum pressure differential. Its specialised NAMUR arrangement purges exhaust air into the actuator spring chamber, helping protect the spring mechanism from contaminated external atmospheres.
With a large 5mm orifice, 8 L/min water flow, switching capability up to 900 cycles per minute and a life expectancy exceeding 20 million cycles, the 30318-5 combines fast actuator control with ATEX Ex db IIC and Ex tb IIIC explosion protection.
Valve Function & Operation
Function: 3/2 way universal
Operation: Direct acting
Connection: NAMUR interface
Working pressure: 0 to 10 Bar
The universal 3/2 configuration provides flexible pneumatic control, while the direct-acting design allows operation from zero pressure differential through to 10 Bar.
The valve is particularly suited to direct control of spring-return pneumatic actuators where reliable fail-safe movement and rapid switching are required.
Spring Chamber Exhaust Purging
An important feature of the Rotex 30318-5 is its exhaust arrangement.
Rather than simply exhausting pilot air directly to the surrounding atmosphere, exhaust air is purged into the spring chamber of the actuator.
A non-return plug is fitted to the exhaust port, helping prevent external contaminated air from being drawn back into the actuator spring chamber.
This arrangement is particularly useful on outdoor and industrial process installations where moisture, dust or corrosive atmospheres could otherwise enter the spring chamber during repeated actuator operation.
Air & Power Failure Operation
When correctly installed with a spring-return actuator, the arrangement provides air and electrical power fail return.
If the electrical signal is removed, or the pneumatic supply is lost, the actuator spring provides the mechanical force required to return the actuator to its predetermined fail-safe position.
This makes the 30318-5 particularly suitable for automated process valves requiring a defined fail position.
Pressure & Flow Performance
Working pressure:
0 to 10 Bar
Orifice:
5.0mm
Water flow:
8 L/min at 1 Bar pressure drop
The relatively large 5mm orifice provides fast flow through the control valve, helping achieve rapid actuator response.
Construction & Materials
Body options:
Aluminium
316 stainless steel CF8
Internals:
Stainless steel
Shading ring:
Copper standard
Silver optional
Without shading ring optional
The 316 stainless steel body option provides increased corrosion resistance for demanding process, offshore and exposed industrial environments.
Seal & Media Compatibility
Available seal materials:
NBR
FKM (Viton®)
Viton GLT
Fluorosilicone
Suitable media include:
Air
Water
Gases
Compatible process fluids
For pneumatic actuator control, compressed air is the principal application. Other media should be checked against the selected seal, body and internal materials before ordering.
High-Speed & Long-Life Operation
The Rotex 30318-5 is designed for demanding automated applications:
Maximum cycling: 900 cycles/minute
Life expectancy: >20 million cycles
Vibration resistance: Up to 9G
Shut-off: Bubble tight
Mounting: Any position
These characteristics make the valve particularly suitable for high-cycle automated process valves and machinery operating in hazardous environments.
ATEX Ex d Solenoid Operator
Coil: Rotex III 14mm
Power: 8 Watts
Insulation: Class H
Protection: IP66 / IP67
Surge suppression: Included
Explosion protection:
Ex d IIC T4-T5-T6
Voltage Options
Available voltages:
12V DC
24V AC/DC
48V AC/DC
110V AC/DC
230V AC/DC
Voltage tolerance:
±20%
Except for the 12V DC version, the ATEX coils are rectified and accept the corresponding AC 50/60Hz or DC input.
Explosion-Proof Enclosure
Enclosure options:
Aluminium
316 stainless steel
Conduit entry:
M20 × 1.5
or
1/2" NPT
Entry orientation:
Horizontal
The enclosure provides IP66/IP67 ingress protection for demanding industrial and outdoor hazardous-area installations.
ATEX Certification
ATEX certificate:
TI22ATEX 278X
Marking:
II 2GD
Gas:
Ex db IIC T6 / T5 Gb
Dust:
Ex tb IIIC T80°C / T95°C Db
Protection:
IP66 / IP67
Certified ambient temperature:
T6: -40°C to +60°C
T5: -40°C to +70°C
This provides explosion protection for both hazardous gas and combustible dust environments when installed in accordance with the applicable certification requirements.
Typical Applications
The Rotex 30318-5 is particularly suited to spring-return pneumatic actuators controlling ball valves, butterfly valves and other quarter-turn process valves.
Typical installations include oil and gas plants, chemical and petrochemical processing, refineries, tank farms, process skids, offshore equipment, water treatment and other hazardous-area automated valve systems.
Why Choose the Rotex 30318-5?
The key advantage of the 30318-5 is that it combines direct NAMUR mounting, spring-chamber exhaust purging and ATEX Ex d protection in a high-performance actuator control valve.
The exhaust purge arrangement is especially useful because clean exhaust air is directed into the spring chamber while the non-return exhaust plug helps prevent contaminated atmospheric air from entering the actuator.
Combined with zero-differential operation, a 5mm orifice, 900 cycles per minute, 9G vibration resistance and >20 million cycle life, this makes the 30318-5 a strong choice for demanding hazardous-area spring-return actuator applications.
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