Limitorque QX Quarter-Turn Electric Actuator

The Limitorque QX is a quarter-turn electric valve actuator designed specifically for the 90-degree rotation service required by ball valves, butterfly valves, and plug valves — the three valve types that dominate process plant automated valve inventories in ARAMCO GOSPs, gas compression stations, refinery process units, and SABIC petrochemical plants. The QX-05 model provides output torque up to 500 Nm in quarter-turn operation, covering ball valves from 2" through 8" Class 300 and butterfly valves up to 24" in the seat torque range encountered in hydrocarbon process service at ARAMCO Eastern Province facilities. The QX's inherent position control accuracy of ±0.5 degrees enables it to operate as a modulating positioner for butterfly valve throttling control in addition to its primary open-close function — providing a single hardware platform for both on-off block valve service and flow control service, simplifying spare parts programmes for ARAMCO instrument departments.

The QX actuator's internal design uses a precision worm gear with integral position sensing to provide absolute position feedback without requiring a separate positioner, and the multi-turn position sensor data is available on HART, Modbus RTU, and PROFIBUS DP protocols — matching the three principal fieldbus architectures in ARAMCO's Honeywell TPS, Yokogawa Centum, and Siemens PCS7 DCS installations. The fail-safe spring return option provides powered-close or powered-open on loss of electrical supply — the fundamental safety requirement for ESD ball valves at ARAMCO GOSPs where process isolation on power failure is mandated by ARAMCO Process Hazard Analysis. The QX is certified to Ex d IIB T4 for Zone 1 and Zone 2 hazardous area classification, and to IP67 water ingress protection, covering both the typical GOSP process area classification and the coastal and offshore environments of ARAMCO's marine production facilities.

Saudi ARAMCO specifies Limitorque QX actuators in its SAES-J-902 standard for automated quarter-turn valves, and QX units are in service on ball valve ESD valves, automated isolation valves, and modulating butterfly valves at ARAMCO facilities across the full Eastern Province production system — from offshore Manifa and Safaniya platforms through the GOSP and gas plant network to the Ras Tanura refinery and Jubail Industrial Port export terminal. SABIC specifies QX actuators for quarter-turn process isolation in ethylene, propylene, and butene production trains at its Jubail complex, where the combination of Ex d hazardous area certification and SIL 2 functional safety rating satisfies both the process area classification and the safety function requirements for ESD valve service. The QX's compact, lightweight enclosure also makes it the preferred actuator for overhead valve installations at elevation where maintenance access is restricted — a common configuration in SABIC cracker distillation column overhead systems.

Razz Middle East supplies Limitorque QX-05 and QX-10 units in 400V/3-phase motor configuration with Ex d IIB T4 certification and HART/Modbus RTU communications, ready for immediate delivery to ARAMCO and SABIC project sites across the Kingdom. We supply QX actuators as bare units or as complete valve-actuator assemblies with Flowserve Worcester or Valtek ball and butterfly valves factory-mounted, tested, and supplied with a single data dossier — a procurement format that simplifies ARAMCO vendor data requirement (VDR) management and reduces EPC contractor site assembly labour. Our automation engineers provide IEP and actuator torque sizing, and we hold calibration data sheets and loop test records as part of the standard commissioning package.