Rotork CVA Precision Control Valve Electric Actuator
Overview
The Rotork CVA brings electric actuation to process control valves that have traditionally relied on spring-diaphragm or piston pneumatic actuators. Rotork builds the range in two drive actions, the CVL linear actuator and the CVQ part-turn actuator, so one electronic platform can automate globe, rotary and eccentric control valves. For a plant that is trying to cut compressed-air consumption, remove instrument-air leaks or install control valves where no air supply exists, the Rotork CVA offers accurate positioning from a simple power and signal cable.
Seven Star LLC supplies the Rotork CVA to refineries, power stations, desalination plants and industrial facilities across Oman and the GCC. Our Muscat engineers help match CVL thrust or CVQ torque to the valve, verify the supply voltage, and prepare quotations for new installations as well as for replacing pneumatic actuators on existing valves.
Operating Principle
Inside the Rotork CVA, a high-efficiency brushless DC motor drives a durable spur gear train that is lubricated for life. In the CVL the output is a linear stem, and in the CVQ a part-turn shaft whose base conforms to MSS SP-101 or ISO 5211. Rotork describes the continuous-rated brushless motor as maintenance-free, even under continuous modulation, because there are no brushes to wear and no relay switching of the motor on every correction.
Accurate positioning relies on what Rotork calls Dual Sensor technology. Two independent 12-bit rotary magnetic encoders monitor the motor output and the actuator output shaft, so backlash and gear inertia do not corrupt the reading, and the actuator can hold the demanded position to 0.1 percent. Direct thrust or torque measurement protects the valve, and the self-locking drive resists back-drive up to 125 percent of the rated force, so process pressure cannot push the valve off its set point.
Engineering Design of the Rotork CVA
The Rotork CVA is housed in a double-sealed enclosure rated to IP68. The terminal compartment is separated from the electronics by a watertight seal, so the actuator stays protected even if the cover is left off during wiring or a cable gland is poorly sealed. Four conduit entries are provided, and the control and indication circuits can be supplied as intrinsically safe. AC units contain a switch-mode supply that accepts 100 to 240 VAC at 50 or 60 Hz, with an optional 24 VDC supply.
Set-up is performed with a generic field communicator or over Bluetooth, and a tri-colour status LED shows the actuator condition. An optional hand drive allows manual valve operation, and speed can be adjusted from 5 to 100 percent in one percent increments. The range performance figures from Rotork list CVL sizes from 500 up to 5,000, with up to 22,241 N maximum thrust and strokes to 114.3 mm, and CVQ sizes of 1,200 and 2,400 with up to 271 Nm.
Key Features
The Rotork CVA range packages precision and diagnostics into a compact electric drive. Key features of the Rotork CVA include:
- Linear drive action in the CVL and part-turn drive action in the CVQ, using one common control platform.
- Continuous unrestricted modulation duty, classified S9, from a brushless DC motor with no routine maintenance.
- Positioning to 0.1 percent with Dual Sensor technology and scalable 4-20 mA input characterisation.
- An on-board datalogger as standard, including dwell time recorded for each one percent of stroke to reveal valve oversizing or loop instability.
- Configurable fail-to-position action through a supercapacitor reserve power pack, with an optional solenoid lock.
- Explosion-proof construction to international standards, and optional intrinsically safe control inputs and feedback outputs.
- Bluetooth for local set-up, control and diagnostics, plus HART, Foundation Fieldbus, Profibus, Pakscan, Modbus and RIRO communication options.
- Single-phase or DC supply, so the actuator can be installed without a three-phase motor circuit.
Industrial Applications
Control valves operate in the most demanding loops in a plant, for example feedwater, desuperheater spray, fuel gas, antisurge and level control, and the Rotork CVA suits these duties because it responds to small signal changes without the slip-stick behaviour of a diaphragm. Rotork publishes a step response of about 0.175 seconds to the T86 point for the CVA, and the dwell-time data recorded by the datalogger gives operators a way to check that a control valve is correctly sized. In Oman, where remote wellheads, solar-powered sites and desalination plants limit the availability of clean instrument air, electric control valve actuation is an attractive option. Plants that already use a Emerson DVC6200 controller on pneumatic valves can compare it with the Rotork CVA when planning an air-free retrofit.
Seven Star LLC supplies the Rotork CVA for valves in the Sohar and Salalah economic zones, power and water utilities, and chemical and fertiliser plants. Typical valve bodies include a Masoneilan Class 300 diaphragm control valve or a XOMOX Type 800 butterfly valve that is being converted from pneumatic to electric actuation. Our engineering support in Muscat shortens clarification, and lead time is confirmed at quotation.
Technical Specifications
The table below gives the performance summary published by Rotork for the Rotork CVA range. Torque and thrust depend on the sensor setting, and speed is adjustable.
| Parameter | Specification |
|---|---|
| Model | Rotork CVA range: CVL linear and CVQ part-turn |
| CVL sizes | CVL-500, 1000, 1500 and 5000 |
| CVL maximum thrust | 2,224 N (500), 4,448 N (1000), 6,672 N (1500), 22,241 N (5000) |
| CVL stroke | 38.1 mm, 50.8 mm and 114.3 mm depending on size |
| CVQ sizes and torque | CVQ-1200 up to 135.5 Nm, CVQ-2400 up to 271 Nm |
| Positioning accuracy | 0.1 percent with Dual Sensor technology |
| Speed adjustment | 5 to 100 percent in 1 percent increments |
| Duty | Continuous modulation, S9 |
| Supply | 100 to 240 VAC 50/60 Hz, optional 24 VDC; single-phase or DC |
| Enclosure | Double-sealed, IP68 |
| Back-drive resistance | Up to 125 percent of rated force |
| Communication | 4-20 mA, HART, Foundation Fieldbus, Profibus, Pakscan, Modbus, RIRO |
Request a Quote for Rotork CVA
To request a quotation for the Rotork CVA, send Seven Star LLC the valve make and size, stroke or torque requirement, signal type, supply voltage and area classification. Our instrumentation division in Muscat will confirm the CVL or CVQ size, check the fail-to-position option and return pricing with the manufacturer brochure for your records. Seven Star LLC supplies genuine Rotork equipment with warranty and local engineering support across Oman and the GCC, so submit your RFQ today.
- Brochure Rotork CVA Control Valve Actuator Sales Brochure Download
Rotork product families on this page
The IQ3 is the intelligent multi-turn electric actuator for gate, globe and sluice valves, and the IQT3 is its part-turn counterpart for ball, butterfly and plug valves. For control valves there are the CVA and CMA electric actuators, built for continuous modulating duty. The Skilmatic SI3 is a self-contained electro-hydraulic actuator used where a fail-safe stroke is required. On the fluid power side the page lists GP/GH scotch yoke pneumatic and hydraulic actuators and the CP compact pneumatic quarter-turn unit. Two instrument brands sold under the Rotork name complete the list: Fairchild, with the Model 1000 no-bleed precision regulator, and YTC, with the YT-1000 electro-pneumatic and YT-3300 smart positioners.Where Rotork actuators are used
Typical duties are isolation and block valves on pipelines and tank farms, motor-operated valves in refineries and power plants, sluice gates and large butterfly valves in water and wastewater works, and emergency shutdown valves on oil and gas facilities across the GCC.Ordering Rotork actuators and parts: what we need
For an existing unit, send the serial number and the wiring diagram number from the nameplate; these two identify the exact build. For a new selection we need the valve type and size, torque or thrust, stem or shaft details, operating time, supply voltage, phase and frequency, the hazardous area certification, and any bus or remote control option. For pneumatic units add the air supply pressure and the fail position.Browse Rotork products by category: Valve Positioner, Valve Actuator.
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