Limitorque LQI Compact Quarter-Turn Electric Actuator

Overview

The Limitorque LQI is a compact quarter-turn electric actuator for ball valves, butterfly valves, plug valves and dampers. Where the QX and MX families target critical process duty with advanced electronics, the Limitorque LQI is the simpler, cost-conscious option: a rugged aluminium-housed actuator with standard limit switches, a clutchless handwheel and a choice of on-off, floating or modulating control. The manufacturer describes it as combining reliable performance with a lower total cost of ownership across power, oil and gas, chemical, water and general industry service.

Seven Star LLC supplies the Limitorque LQI from Muscat for projects across Oman and the GCC, from water-network valve chambers to utility blocks in industrial estates. Because the range spans sizes from LQI 1 to LQI 13, the same product family can cover small dampers and large butterfly valves, and our team can check the torque, flange and supply voltage in the brochure table against the valve data sheet before a quotation is issued.

Drive Principle

Inside the Limitorque LQI, a high-efficiency AC or DC motor drives a self-locking epicyclic gear system that turns the output shaft through ninety degrees. The self-locking gear train holds the valve in position without a brake, and the lubricant is a permanent fill, so there is no routine greasing in normal service. Two auxiliary limit switches are standard, together with an anti-condensation heater and motor thermal overload protection, and a mechanical position indicator shows the valve position at a glance, with a raised indicator on weatherproof models.

Manual operation is by a clutchless handwheel override on larger sizes, which keeps the valve operable during a power loss without a declutch lever to operate. Externally accessible, adjustable mechanical stops set the end-of-travel position, and the mounting flange follows ISO 5211 so the actuator bolts directly onto standard quarter-turn valve tops. Torque switches are an option, as is a potentiometer for position feedback and an analogue input and output board for modulating service with 4-20 mA, 1-5 V or 2-10 V signals.

Engineering Design of the Limitorque LQI

The housing of the Limitorque LQI is polyester powder-coated aluminium with stainless steel captive screws, and weatherproof versions are rated IP67 with an optional IP68 rating of 7 metres for 72 hours under IEC 60529. A C5 paint system is offered for corrosive environments. The brochure gives an operating temperature range of -30 to +65 degrees Celsius for the standard specification, and the explosion-proof certificates list ambient limits of -30 to +70 degrees Celsius.

Explosion-proof versions carry ATEX marking II 2 GD Ex db IIB T4 Gb and Ex tb IIIC T130 C Db, IECEx equivalents and CSA certification for North American zone and division systems. Power supply choices include 12 or 24 V AC and DC, 110 to 120 V and 220 to 240 V single phase, and three-phase supplies up to 480 V in weatherproof models. Standard duty is 30 percent, with extended duty up to 75 percent on selected units, and Modbus RTU RS485 control is optional on listed sizes. A local control unit with local-remote and open-stop-close selectors and a junction box for external wiring are available.

Key Features

These characteristics make the Limitorque LQI a practical choice for standard quarter-turn automation:

• Eighteen frame sizes from LQI 1 (35 Nm) to LQI 13 (4,500 Nm) allow close matching of actuator torque to valve demand.
• A self-locking, permanently lubricated epicyclic gear system holds position and removes routine greasing.
• A clutchless handwheel override keeps valves operable during a power loss on units that include it.
• Two auxiliary limit switches, a heater and motor thermal protection are standard, which shortens set-up time on site.
• IP67 weatherproof enclosures with an IP68 option, and a C5 paint option for aggressive coastal atmospheres.
• ATEX, IECEx and CSA explosion-proof models cover gas groups IIB and dust hazards up to size LQI 8 as listed in the brochure.
• Discrete, floating, 4-20 mA modulating and Modbus RTU control options fit most valve-automation schemes.
• Four-wire discrete and push-button local control options and a handwheel or lever override depending on the size.

Industrial Applications

In Oman the Limitorque LQI is a natural fit for cooling-water and seawater butterfly valves, raw-water and treated-water isolation in desalination and supply networks, and damper drives in HVAC and district cooling plants. Its sealed housing and corrosion-resistant coating suit the humidity of the Batinah coast and the salt-laden air of Duqm, Sur and Salalah, and the compact size helps in crowded valve chambers and pipe racks.

Industrial plants in Sohar and Rusayl use compact actuators on utility headers, and engineers can compare the Limitorque LQI with the AUMA SQ part-turn actuator and the AUMA SQR modulating part-turn actuator when sizing a mixed fleet, or specify a AUMA GS part-turn gearbox when a worm gearbox is needed to reach the required torque on a manual valve. For hazardous areas, the explosion-proof variants allow a single actuator family across safe and classified locations.

Technical Specifications

The values below are taken from the manufacturer brochure; confirm the exact frame, voltage and certification before ordering.

Request a Quote for Limitorque LQI

To request a quotation for the Limitorque LQI, send Seven Star LLC the valve torque, flange size, supply voltage, control signal and hazardous-area class. Our team will propose the matching frame, share the official brochure and confirm delivery to Oman and the GCC. Ask us as well about local control units and spare parts so every Limitorque LQI on your valve schedule is ready for commissioning.