Description
NAMUR ATEX Ex ia Solenoid Valve – Rotex 30318LW
The Rotex 30318LW is an ATEX and IECEx Ex ia intrinsically safe 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 works from 0 to 10 Bar without requiring a minimum pressure differential. A push/turn manual override provides local operation for commissioning, testing and maintenance.
A key feature of the 30318LW is its spring-chamber exhaust purge system. Exhaust air is directed into the actuator spring chamber, while a non-return plug helps prevent contaminated external air from entering the actuator. Combined with the low-power 24V DC Rotex IV intrinsically safe operator, this makes the valve particularly well suited to hazardous-area actuator control.
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 for spring-return actuator applications.
Its direct-acting construction means the valve operates from zero pressure differential, making it suitable across the complete stated 0–10 Bar working range.
Spring Chamber Exhaust Purging
The Rotex 30318LW is specifically designed to protect the spring chamber of a spring-return pneumatic actuator.
Rather than exhausting directly to atmosphere, the valve purges exhaust air into the actuator spring chamber.
A non-return plug fitted to the exhaust port helps prevent external contaminated air from being drawn back into the spring chamber.
This can be particularly beneficial in outdoor, dusty, humid or corrosive industrial environments where atmospheric contamination could otherwise enter the actuator during repeated operation.
Air & Power Fail Return
When correctly installed with a suitable spring-return actuator, the 30318LW allows the actuator to return to its predetermined fail-safe position following loss of the electrical signal or pneumatic supply.
This makes the combination particularly useful for automated process valves requiring a defined air-fail and power-fail position.
Manual Override
The Rotex 30318LW incorporates a push/turn manual override facility.
This allows local mechanical operation of the solenoid valve for commissioning, testing and maintenance without relying solely on the electrical control signal.
Pressure & Flow Performance
Working pressure:
0 to 10 Bar
Minimum differential:
0 Bar
Orifice:
5.0mm
Water flow:
8 L/min at 1 Bar pressure drop
The 5mm internal orifice provides high flow for fast pneumatic 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 and exposed industrial installations.
Seal & Media Compatibility
Available seals:
NBR
Viton GLT
Fluorosilicone
Suitable media include:
Air
Water
Gases
Compatible process fluids
For NAMUR actuator control, compressed air is the primary application. Other media should be confirmed against the selected seals and complete valve construction.
Low-Power Ex ia Solenoid
Coil: Rotex IV 14mm
Design: With booster circuit
Nominal voltage: 24V DC
Power: 1.8 Watts
Insulation: Class H
Ingress protection: IP67
The low-power Rotex IV operator is designed for use within a correctly engineered intrinsically safe circuit while providing the actuation requirements of the NAMUR valve.
ATEX & IECEx Intrinsic Safety
Approvals:
ATEX
IECEx
IECEx certificate:
IECEx BAS 12.0128X – Issue 1
ATEX certificate:
Baseefa12ATEX0243X – Issue 1
Gas marking:
Ex ia IIC T5 Ga
-60°C ≤ Ta ≤ +75°C
Ex ia IIC T6 Ga
-60°C ≤ Ta ≤ +60°C
Dust marking:
Ex ia IIIC T200 125°C IP67 Da
-60°C ≤ Ta ≤ +75°C
The Ga and Da equipment protection levels provide a very high level of protection for hazardous gas and combustible dust applications when correctly installed as part of the intrinsically safe system.
Intrinsically Safe Parameters
Minimum operating parameters:
Voltage: 12.5V
Current: 25.5mA
Power: 0.3W
Entity parameters:
Ui: 32V DC
Ii: 230mA
Pi: 2.3W
Li: 0
Ci: 0
The associated intrinsically safe barrier or galvanic isolator must comply with the certified entity parameters while also supplying the minimum voltage and current required for reliable operation.
Typical Applications
The Rotex 30318LW is particularly suited to intrinsically safe control of spring-return pneumatic actuators operating ball valves, butterfly valves and other quarter-turn process valves.
Typical applications include oil and gas installations, chemical and petrochemical processing, refineries, process skids, tank farms, offshore equipment, water treatment and other hazardous-area automated valve systems.
Why Choose the Rotex 30318LW?
The 30318LW combines several useful features in one compact NAMUR valve: Ex ia intrinsic safety, zero-differential direct acting operation, spring-chamber exhaust purging and manual override.
The 5mm orifice provides high-flow actuator control, while the exhaust purge arrangement helps protect the actuator spring chamber from contaminated external air.
For installations where an intrinsically safe electrical circuit is preferred to an Ex d flameproof operator, the 30318LW provides the Ex ia equivalent to the 30318-5 NAMUR concept, with a low-power 24V DC Rotex IV operator.
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