Rotork CP Compact Pneumatic Quarter-Turn Actuator
Overview
The Rotork CP range brings heavy-duty scotch-yoke design to small and medium quarter-turn valves. These actuators are modular, compact and rugged, and they are offered in double-acting (CP/D) and spring-return (CP/S) versions. Rotork applied the design concepts of its large GP and GH actuators to the CP range, so a plant engineer gets a robust, serviceable pneumatic actuator without the bulk of a rack-and-pinion unit of similar torque.
Seven Star LLC supplies the Rotork CP to valve packagers, EPC contractors and plant maintenance teams across the Sultanate of Oman and the GCC. We work from the Rotork brochure and torque tables to match the actuator to the valve and the available air supply, and our Muscat team can include the switch box, positioner and solenoid needed for a complete automated valve assembly.
Operating Principle
In the Rotork CP, compressed air acts on a piston, and the piston rod drives a yoke that converts linear motion into a 90 degree rotation of the output shaft. A scotch-yoke mechanism provides high torque at the start and the end of the stroke, which is where a ball, plug or butterfly valve needs the most force to unseat and to seal. Double-acting units use air for both directions, whereas spring-return units use the air stroke to compress a spring cartridge, and the spring brings the valve to its fail position when air is lost.
Safety is designed into the cartridge. The springs sit inside a cartridge on the inboard side of the cylinder and are contained by the piston and piston rod, so spring force cannot be released inadvertently during maintenance. The design also gives access to the piston seal without taking the spring cartridge apart, and different springs can be fitted in the same container to alter the torque characteristic.
Engineering Design of the Rotork CP
The Rotork CP has a ductile iron housing that gives a strong, lightweight body, and the parts that rub or seal are treated with electroless nickel and chromium plating or a nitro-oxidation process for hardness and corrosion resistance. Steel, bronze and PTFE bearings support the piston rod, so misalignment and wear are reduced, and O-ring sealing gives protection certified to IP66M and IP67M.
Mounting is simple. The valve interface conforms to ISO 5211, and the NAMUR topworks interface allows a switch box, positioner or solenoid to be fitted without brackets. Optional extras include an integral manual override, control systems, custom actuator-to-valve adaptors and stem couplings, and custom paint. The jackscrew override can be fitted at any time, even in the field, which is useful on valves that were originally specified without one.
Key Features
The Rotork CP range delivers dependable quarter-turn force in a compact package. Key features of the Rotork CP include:
- Modular scotch-yoke design in double-acting (CP/D) and spring-return (CP/S) configurations that share most components.
- Torque output up to 4,500 Nm (39,828 lbf.in) at an operating pressure of up to 12 bar (174 psi).
- Standard temperature range of -30 to +100 °C, with low and extreme-low versions down to -40 °C and -60 °C.
- Spring cartridge that is inherently safe, since the spring force is contained by the piston and rod.
- Wearing surfaces treated for corrosion resistance and long seal life, with steel, bronze and PTFE bearings on the piston rod.
- NAMUR topworks interface and ISO 5211 valve interface for standard accessories.
- IP66M and IP67M protection by O-ring sealing, with a ductile iron housing.
- Options for jackscrew manual override, custom paint and special couplings.
Industrial Applications
The Rotork CP is used on ball, plug and butterfly valves in process pipelines, tank and terminal manifolds, water treatment skids, chemical dosing and utility services. Because it operates on plant air and uses no electrical drive, it is a natural choice in Zone 1 and Zone 2 areas of oil and gas facilities in Oman, where a pneumatic stroke with a certified solenoid and switch box avoids introducing electrical equipment on the valve itself. The compact body also suits skid-mounted packages, where space around the valve is limited. A typical valve assembly pairs the actuator with a Parker Lucifer 341N01 NAMUR solenoid valve and a Fisher 3610J positioner for modulating duty.
Seven Star LLC supplies the Rotork CP for projects in the Sohar and Salalah economic zones, in desalination plants and in power stations, backed by engineering support in Muscat. Buyers comparing pneumatic drive technology can also review the Camozzi Series 61 pneumatic cylinder for linear duties. For larger valves, Rotork offers the GP and GH range, which uses the same scotch-yoke principle at much higher torque.
Technical Specifications
The table summarises the published data for the Rotork CP range from the Rotork brochure. Torque output and dimensional data for each size are available in separate manufacturer documents.
| Parameter | Specification |
|---|---|
| Model | Rotork CP range, CP/D double-acting and CP/S spring-return |
| Actuator type | Compact scotch-yoke pneumatic quarter-turn actuator |
| Torque output | Up to 4,500 Nm (39,828 lbf.in) |
| Operating pressure | Up to 12 bar (174 psi) |
| Temperature range | Standard -30 to +100 °C; low -40 °C; extreme low -60 °C |
| High temperature | Up to 160 °C on request |
| Housing | Ductile iron |
| Valve interface | ISO 5211 |
| Accessory interface | NAMUR topworks |
| Environmental protection | IP66M and IP67M by O-ring sealing |
| Options | Manual override, control systems, custom adaptors, custom paint |
Request a Quote for Rotork CP
To request pricing for the Rotork CP, send Seven Star LLC the valve type and size, breakaway and running torque, air supply pressure, fail direction and accessory requirements. Our instrumentation division in Muscat will select the actuator model, offer the matching switch box, positioner and solenoid, and provide the Rotork brochure with the quotation. Seven Star LLC supplies genuine Rotork equipment with warranty and local engineering support across Oman and the GCC, so send your RFQ for the Rotork CP today.
- Brochure Rotork CP Range Compact Pneumatic Actuator 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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