Description
ATEX Ex ia 5/2 Monostable Solenoid Valve – Rotex 51440A
The Rotex 51440A is a high-performance ATEX and IECEx Ex ia intrinsically safe 5/2 way monostable solenoid valve designed for hazardous-area pneumatic and process control applications requiring low-power electrical operation, fast switching and dependable fail-safe return.
Featuring a single-solenoid monostable design, the valve switches when energised and automatically returns to its normal position when power is removed. Internal pilot operation provides reliable directional control at working pressures from 2 to 10 Bar.
The valve is available with aluminium, brass or 316 stainless steel CF8 bodies and combines bubble-tight shut-off, vibration resistance up to 9G, switching rates up to 1200 cycles per minute and a life expectancy exceeding 20 million cycles.
Valve Function & Operation
Function: 5/2 way monostable
Actuation: Single solenoid with return
Operation: Internally piloted
The five-port, two-position configuration is designed primarily for controlling double-acting pneumatic cylinders and actuators.
When the intrinsically safe solenoid is energised, the valve changes position and reverses the pressure and exhaust flow paths. When the electrical signal is removed, the valve automatically returns to its normal position.
As an internally piloted valve, sufficient pressure differential must be maintained for reliable switching.
Operating pressure: 2 to 10 Bar
Minimum differential: 0.5 or 1 Bar, depending on configuration.
Ports, Orifice & Flow
Standard connection: 1/4" BSP
Optional connection: 1/4" NPT
Orifice: 6mm
Water flow: 14 L/min at 1 Bar pressure drop
The 6mm flow path provides good capacity for actuator and directional-control applications while retaining fast switching performance.
Construction & Materials
Body options:
Aluminium
Brass
316 stainless steel CF8
Internals: Stainless steel
Shading ring: Copper
Optional shading ring:
Silver
Without shading ring
Available seal materials:
NBR
FKM (Viton®)
EPDM
Fluorosilicone
The choice of body and sealing materials allows the valve to be configured for a broad range of compatible industrial media and operating environments.
Media Compatibility
Suitable media include:
Air
Water
Gases
Compatible process fluids
For conventional 5/2 actuator control, clean compressed air would typically be the primary medium.
For other gases or liquids, compatibility should be confirmed against the selected body, seal and internal materials.
High-Speed Performance
The Rotex 51440A provides impressive mechanical performance for an intrinsically safe directional valve:
Bubble-tight shut-off
Vibration resistance: Up to 9G
Maximum cycling: 1200 cycles/minute
Life expectancy: >20 million cycles
This combination makes the valve particularly suitable for frequently operated pneumatic equipment and automated hazardous-area process systems.
ATEX & IECEx Intrinsic Safety
The Rotex 51440A uses a low-power intrinsically safe solenoid operator certified for hazardous gas and dust atmospheres.
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 dust applications, subject to correct intrinsically safe system design and installation.
Intrinsically Safe Coil
Coil: III 14mm with booster circuit
Nominal voltage: 24V DC
Maximum power: 2.3 Watts
Protection: IP67
Insulation: Class H
The booster circuit enables reliable valve actuation while maintaining the low electrical power requirements necessary for intrinsically safe operation.
Intrinsically Safe Parameters
Entity parameters:
Ui: 32V DC
Ii: 230mA
Pi: 2.3W
Li: 0
Ci: 0
Minimum operating parameters:
Voltage: 10V
Current: 20mA
Power: 0.20W
The associated intrinsically safe barrier or galvanic isolator must be selected to comply with these certified entity parameters and the requirements of the complete Ex ia circuit.
Typical Applications
Typical applications include hazardous-area pneumatic actuators, double-acting process valves, oil and gas installations, petrochemical plants, chemical processing, offshore equipment, process skids, industrial automation and other Zone-classified systems requiring intrinsically safe directional control.
Why Choose the Rotex 51440A?
The Rotex 51440A combines Ex ia intrinsic safety with high-speed 5/2 monostable directional control.
Its low-power 2.3W operator, 1200 cycles/minute capability, >20 million cycle life, 9G vibration resistance and choice of aluminium, brass or 316 stainless steel bodies make it a strong option for demanding hazardous-area actuator control systems.
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