AUMA SQREx Explosion-Proof Modulating Part-Turn Actuator
Overview
The AUMA SQREx is the explosion-proof, modulating-duty version of the AUMA SQ .2 part-turn actuator. It takes the control-grade capability of the SQR, with class C duty at S4 – 25 % and up to 1,500 starts per hour, and places it in a certified enclosure for plants where explosive gas atmospheres can occur. Explosion-proof devices of this kind are designed so that they do not act as an ignition source: they neither generate ignition sparks nor reach hot surface temperatures that could ignite the surrounding atmosphere. Certification is performed in close collaboration with national and international certification bodies, and the SQREx carries ATEX, FM and IECEx approvals.
In Oman and the GCC, Seven Star LLC proudly supplies the AUMA SQREx to oil and gas, petrochemical, fuel storage and utility operators in the Sultanate of Oman and across the GCC. Hazardous-area projects around Sohar, Salalah and the wider Muscat region demand correctly certified equipment, the right documentation and a supplier that can answer certification questions quickly. Seven Star LLC supports engineers with the dimension sheets, approvals data and configuration advice they need to specify the SQREx correctly the first time.
Operating Principle
Mechanically the AUMA SQREx works like the SQR: a three-phase AC motor drives a gear stage that turns the output shaft through a part-turn angle of 75 to 105 degrees, with limit and torque sensing switching the drive off at the end position or on overload. The operating time for 90 degrees lies between 8 s and 100 s. What changes is the construction. The electrical compartments are built in flameproof and increased-safety protection types, so any internal ignition cannot propagate to the outside atmosphere and surface temperatures stay inside the stated temperature class, T4 or T3 depending on the configuration.
Modulating duty adds a second consideration. A positioning actuator in a hazardous area starts and stops many times per hour, and each start produces motor heating that must be managed within the temperature class rules. The AUMA SQREx is dimensioned for class C operation at S4 – 25 %, with a modulating torque range of 75 Nm to 1,200 Nm, so the same device that is certified for explosive atmospheres can also run in a control loop. Position setpoints and feedback travel through the AUMA controls, so a valve in Zone 1 can be regulated with the same repeatability as a valve in a safe area.
Engineering Design of the AUMA SQREx
The AUMA SQREx uses the SQ .2 modular platform with limit and torque sensing, a 3-phase AC motor, a handwheel for manual operation and a mechanical position indicator. The electrical connection is made with the AUMA plug/socket connector, with terminals as an option, and cable entries are available in different versions. Valve attachments follow DIN and EN ISO standards, and the torque is delivered to the valve through a splined coupling in unbored, square, two-flat or keyway versions. Enclosure protection is IP68 and the corrosion protection is the KS system.
Ambient temperature capability is −30 °C up to +40 °C or +60 °C depending on the certified configuration, which should be checked against the actual temperature class on the approval. Options include intermediate position switches, switches in tandem version, a position transmitter, a magnetic limit and torque transmitter and, for selected configurations, functional safety up to SIL 2. Dimension sheets cover the SQEx and SQREx 05.2 to 14.2 sizes, including versions with base and lever and with AUMA MATIC AMExC and AUMATIC ACExC controls.
Key Features
The AUMA SQREx pairs hazardous-area certification with modulating performance. The main characteristics are summarised below.
- Certified explosion protection under ATEX, FM and IECEx for potentially explosive atmospheres.
- Modulating duty, class C, S4 – 25 %, with up to 1,500 starts per hour.
- Torque range of 50 Nm to 2,400 Nm and a modulating torque range of 75 Nm to 1,200 Nm.
- Operating time for 90 degrees from 8 s to 100 s with a swing angle of 75 to 105 degrees.
- IP68 enclosure protection with KS corrosion protection for harsh outdoor and coastal sites.
- Handwheel for manual operation and mechanical position indicator that works without power.
- Options for intermediate position switches, tandem switches, position transmitter and magnetic limit and torque transmitter.
- Functional safety up to SIL 2 possible for selected configurations.
Industrial Applications
The AUMA SQREx is selected where a control valve sits inside a classified area and cannot be replaced by a non-certified device. Typical duties include flow and level regulation on crude oil and condensate lines, butterfly valve control in tank farms and loading terminals, positioning of ball and plug valves in gas treatment and metering stations, and cooling-water control in refineries and petrochemical plants. In Oman these facilities concentrate around the industrial zones of Sohar and Salalah, in the Duqm region and along the pipeline corridors serving Muscat, and they usually specify certified devices with traceable documentation.
Seven Star LLC supplies the AUMA SQREx with the supporting certificates and documentation required by project inspectors throughout Oman and the GCC. The SQREx can be combined with the FQMEx fail safe unit where safe closing or opening is required in an emergency, and with AUMA explosion-proof controls, which gives plant owners a coherent range of certified valve automation from a single manufacturer and a single local supplier. Related AUMA products worth comparing with the AUMA SQREx include the AUMA SQEx explosion-proof part-turn actuator, the AUMA SQRVEx and the AUMA FQM/FQMEx fail-safe unit, which cover neighbouring duty types and sizes.
Technical Specifications
The following table summarises AUMA’s published data for the AUMA SQREx .2 type range. Always verify the temperature class and approvals on the nameplate and certificates for the specific configuration.
| Parameter | Specification |
|---|---|
| Model | SQREx .2 type range (SQREx 05.2 – SQREx 14.2) |
| Duty type | Modulating duty, class C, S4 – 25 % |
| Torque range | 50 Nm – 2,400 Nm |
| Modulating torque range | 75 Nm – 1,200 Nm |
| Number of starts (max.) | 1,500 c/h |
| Operating time for 90° | 8 s – 100 s |
| Swing angle | 75° – 105° |
| Enclosure protection | IP68 |
| Corrosion protection | KS |
| Ambient temperature | −30 °C to +40/+60 °C |
| ATEX explosion protection | II 2G Ex db eb IIC (IIB) T4 (T3); II 2G Ex db IIC (IIB) T4 (T3) |
| FM explosion protection (listed on AUMA product page; not on the data sheet) | FM Class I Div 1 Groups (B), C, D T4 (T3C); Class II Div 1 Groups E, F, G T4 (T3C); Class III Div 1 T4 (T3) |
| IECEx | Ex db eb IIC (IIB) T4 (T3); Ex db IIC (IIB) T4 (T3) |
| Motor supply | 3-phase AC motors |
| Functional safety | Up to SIL 2 for selected configurations |
Request a Quote for AUMA SQREx
To request a quotation for the AUMA SQREx, send us the valve data, torque requirement, hazardous-area classification, temperature class and control interface. Seven Star LLC will reply with a formal RFQ response, availability information and the dimension sheet linked on this page. In Oman and the GCC, we supply the certified equipment on request, and our instrumentation division can assist with documentation for inspectors and EPC contractors.
- Datasheet AUMA SQEx 05.2 - SQREx 14.2 Dimension Sheet Download
AUMA actuator and gearbox types
SA multi-turn actuators handle open-close duty on gate and globe valves, and SAR is the modulating version; the listing includes the SA 07.2, SA 10.2 and SA 25.1. SAEx and SAREx are the explosion-proof equivalents. Part-turn duty on ball and butterfly valves is covered by SQ and the modulating SQR, or by an SA actuator combined with a GS part-turn gearbox. LE linear thrust units convert multi-turn output to thrust, and GHT multi-turn gearboxes extend the torque range up to 120,000 Nm. PROFOX is the compact actuator line. Special items include the seawater-resistant SGM and SGMR part-turn actuators with bronze housings, the SVC and SVCR globe valve actuators and the FQM fail-safe unit. Integral controls come as AM or AC versions.Where AUMA electric actuators are used
AUMA actuators are found in water, power, oil and gas, marine and general industry. In practice that means isolation and control valves in water treatment and pumping stations, power plant steam and cooling systems, tank farms and pipelines, and sluice gates and dampers.Ordering AUMA actuators and parts: what we need
For a replacement send photos of the actuator, motor and controls nameplates: type, order number, serial number and wiring diagram number. For a new actuator we need:- valve type, required torque or thrust, and turns or stroke
- valve mounting flange and stem or shaft details
- output speed, duty (open-close or modulating)
- supply voltage and frequency, control signals or fieldbus
- enclosure protection, ambient temperature, Ex requirement
Browse AUMA products by category: Valve Actuator, Industrial Communications.
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