Description
ATEX Ex d 5/2 Bi-Stable Solenoid Valve – Rotex 57440A
The Rotex 57440A is an ATEX Ex d explosion-proof 5/2 bi-stable solenoid valve designed for hazardous-area pneumatic and process control applications requiring the valve to maintain its last switched position.
Featuring 5/2 way bi-stable operation with a single solenoid, the valve uses an internally piloted design and operates from 2 to 10 Bar. Once switched, the bi-stable mechanism maintains the selected valve position until the next switching command, making it particularly useful where maintaining position following removal of the electrical signal is required.
Available with aluminium, brass or 316 stainless steel CF8 body construction, the Rotex 57440A provides bubble-tight shut-off, 9G vibration resistance, cycling rates up to 900 operations per minute and a life expectancy exceeding 20 million cycles.
Valve Function & Operation
Function: 5/2 way bi-stable
Solenoid arrangement: Single solenoid
Operation: Internally piloted
Working pressure: 2 to 10 Bar
The bi-stable mechanism allows the valve to maintain its last switched position rather than automatically returning to its original state when the electrical signal is removed.
This makes the 57440A fundamentally different from a conventional monostable 5/2 valve, which returns to its normal position following removal of the electrical signal.
Pilot Pressure Requirements
The Rotex 57440A is internally piloted and therefore requires a minimum pressure differential for reliable switching.
Minimum differential stated:
0.5 or 1 Bar depending on configuration
Normal working pressure:
2 to 10 Bar
For practical product selection, the 2–10 Bar working range is the important operating specification, while the precise minimum pilot differential should be confirmed against the selected valve configuration.
Ports & Connections
Standard connection:
1/4" BSP
Optional:
1/4" NPT
The compact 1/4" connection and 6mm internal orifice provide good flow capacity for pneumatic actuator and automation applications.
Pressure & Flow Performance
Working pressure:
2 to 10 Bar
Orifice:
6mm
Water flow:
12 L/min at 1 Bar pressure drop
The 6mm orifice provides high flow for rapid switching of pneumatic actuators and other automated equipment.
Construction & Materials
Available body materials:
Aluminium
Brass
316 stainless steel CF8
Internals:
Stainless steel
Shading ring:
Copper standard
Silver optional
Without shading ring optional
The availability of three body materials allows the valve construction to be selected according to environmental and process requirements, with 316 stainless steel providing increased corrosion resistance for demanding installations.
Seal & Media Compatibility
Available seals:
NBR
FKM (Viton®)
EPDM
Fluorosilicone
Suitable media include:
Air
Water
Gases
Compatible process fluids
For pneumatic control applications, compressed air will generally be the primary medium. Other fluids and gases should be checked against the selected body, seal and internal materials.
High-Speed & Long-Life Performance
The Rotex 57440A is designed for demanding automated applications:
Bubble-tight shut-off
Vibration resistance: Up to 9G
Maximum cycling: 900 cycles/minute
Life expectancy: >20 million cycles
These characteristics make the valve particularly suitable for frequently operated process and automation equipment in hazardous areas.
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 12V DC, the ATEX coils are rectified and accept the corresponding AC 50/60Hz or DC input.
Explosion-Proof Enclosure
Available enclosure materials:
Aluminium
316 stainless steel
Conduit entry options:
M20 × 1.5
1/2" NPT
Entry orientation:
Horizontal
The enclosure provides IP66/IP67 protection for demanding industrial and hazardous-area environments.
ATEX Certification
ATEX certificate:
TI22ATEX 278X
Marking:
II 2GD
Gas protection:
Ex db IIC T6 / T5 Gb
Dust protection:
Ex tb IIIC T80°C / T95°C Db
Ingress protection:
IP66 / IP67
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 certification requirements.
Typical Applications
Typical applications include pneumatic actuator control, process automation, oil and gas installations, chemical and petrochemical plants, refineries, process skids, offshore equipment, automated machinery and other hazardous-area pneumatic systems.
The bi-stable design is particularly valuable where the control system requires the spool to remain in its last commanded position after the electrical signal is removed.
Why Choose the Rotex 57440A?
The key difference is its combination of single-solenoid bi-stable operation and ATEX Ex d protection.
Rather than automatically spring-returning when the solenoid signal is removed, the 57440A maintains its last switched position. This can reduce continuous electrical demand and provides a useful control characteristic for applications where the commanded pneumatic state needs to be retained.
Combined with a 6mm orifice, 12 L/min water flow, 900 cycles per minute, 9G vibration resistance and a >20 million cycle life, the 57440A provides a robust hazardous-area solution for demanding 5/2 control applications.
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