Description
ATEX Ex ia Normally Open Solenoid Valve – Rotex 20201
The Rotex 20201 is an ATEX and IECEx Ex ia intrinsically safe normally open solenoid valve designed for hazardous-area applications requiring fail-open operation, low electrical power and reliable control from high vacuum through to 20 Bar.
Featuring 2/2 way normally open, direct-acting operation with the outlet at the top, the valve remains open when electrically de-energised and closes when the intrinsically safe solenoid is energised. Because it is direct acting, no minimum pressure differential is required.
Standard construction uses a 316 stainless steel CF8 body with stainless steel internals, with brass or aluminium body options available. The Rotex 20201 also provides bubble-tight shut-off, 9G vibration resistance, cycling rates up to 1000 operations per minute and a life expectancy exceeding 10 million cycles.
Valve Function & Operation
Function: 2/2 way normally open
Port arrangement: Outlet at top
Operation: Direct acting
The Rotex 20201 is open in its normal de-energised state, allowing media to flow through the valve without electrical power.
When the 24V DC intrinsically safe solenoid is energised, the valve closes and shuts off the flow.
This provides fail-open operation, making the 20201 particularly useful where the process requires the flow path to open automatically following loss of the electrical control signal.
Because the valve is direct acting, it does not depend on line pressure to switch.
Operating pressure:
0 to 20 Bar depending on orifice
High Vacuum & Zero Differential
The Rotex 20201 operates from:
High vacuum down to 10⁻⁶ Torr
through to:
20 Bar positive pressure
The exact maximum pressure depends on the selected orifice.
Its direct-acting construction means the valve can operate at zero pressure differential, providing significantly greater flexibility than a pilot-operated normally open valve.
Ports & Connections
Available BSP connections:
1/8" BSP
1/4" BSP
3/8" BSP
1/2" BSP
Optional NPT threads are available.
The outlet is positioned at the top of the valve, an important installation detail for this normally open configuration.
Orifice & Flow Options
Available orifices:
1.2mm
1.6mm
1.8mm
2.2mm
2.5mm
3.0mm
3.5mm
4.0mm
5.0mm
Water flow: 0.7 to 9 L/min at 1 Bar pressure drop
Maximum working pressure varies according to the selected orifice, so pressure and required flow should be considered together when specifying the valve.
Construction & Materials
Standard body:
316 stainless steel CF8
Optional body materials:
Brass
Aluminium
Internals:
Stainless steel
Shading ring:
Copper standard
Silver optional
Without shading ring optional
The standard stainless steel construction provides a robust option for demanding industrial and hazardous-area applications.
Seal & Media Compatibility
Available seals:
NBR
FKM (Viton®)
EPDM
PTFE / FKM
Hytrel
Suitable media include:
High vacuum
Air
Water
Gases
Compatible process fluids
Seal and body materials should be selected according to the particular medium, pressure, temperature and chemical compatibility requirements.
Performance & Reliability
The Rotex 20201 combines low-power intrinsic safety with strong mechanical performance:
Bubble-tight shut-off
Vibration resistance: Up to 9G
Maximum cycling: 1000 cycles/minute
Life expectancy: >10 million cycles
These characteristics make the valve suitable for frequently operated automated process applications as well as conventional hazardous-area fluid control.
Low-Power Ex ia Solenoid
Coil: Rotex III 14mm
Nominal voltage: 24V DC
Operating power: 2.3 Watts
Booster circuit: 8 Watts
Insulation: Class H
Protection: IP67
The booster circuit provides increased power during initial valve actuation before transitioning to the lower-power operating condition required by the intrinsically safe operator.
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 dust applications when incorporated into a correctly designed intrinsically safe system.
Intrinsically Safe Parameters
Minimum operating parameters:
Voltage: 10V
Current: 20mA
Power: 0.20W
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 these certified entity parameters while also providing sufficient voltage and current for reliable valve operation.
Typical Applications
The Rotex 20201 is particularly suited to hazardous-area systems requiring normally open or fail-open fluid control, including oil and gas installations, chemical and petrochemical processing, high-vacuum systems, process skids, refineries, instrumentation, compressed gas systems and industrial process equipment.
Why Choose the Rotex 20201?
The key advantage of the Rotex 20201 is its combination of normally open fail-safe operation, Ex ia intrinsic safety and zero-differential direct acting control.
It provides reliable operation from 10⁻⁶ Torr high vacuum through to 20 Bar, while the low-power 24V DC operator allows integration into intrinsically safe hazardous-area control circuits.
Compared with the Rotex 20101 normally closed version, the 20201 is the appropriate choice where the process requires the valve to automatically open following loss of the electrical signal.
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