Pneumatic & Electric Actuators — Technical Overview & Selection Guide

Overview

Pneumatic and electric actuators are automated mechanical devices designed to operate valves by converting pneumatic or electrical energy into rotary or linear mechanical movement. They are used for automatic opening, closing, or positioning of valves in piping and process systems.

Pneumatic actuators use compressed air to generate the required torque or thrust, while electric actuators use an electric motor and gear mechanism to operate the valve. Both types are widely used for remote operation, process automation, isolation, and flow-control applications.

Key Features

• Reliable automatic valve operation

• Pneumatic and electric actuation options

• Suitable for on/off and modulating applications, depending on design

• Rotary and linear actuator configurations available

• Suitable for frequent operating cycles

• Fast operation available with suitable actuator configuration

• Manual override options available

• Suitable for remote and automatic operation

• Compatible with PLC, DCS, SCADA, and control systems

• Fail-open, fail-close, or fail-in-place options, where applicable

• Available for various valve sizes and operating torques/thrusts

• Suitable for industrial and process applications

• Available with control, feedback, and monitoring accessories

Common Actuator Types

Pneumatic Actuators

• Double-Acting Pneumatic Actuator

• Spring-Return Pneumatic Actuator

• Rack & Pinion Pneumatic Actuator

• Scotch-Yoke Pneumatic Actuator

• Linear Pneumatic Actuator

Electric Actuators

• Multi-Turn Electric Actuator

• Part-Turn Electric Actuator

• Linear Electric Actuator

• On/Off Electric Actuator

• Modulating Electric Actuator

Technical Selection Parameters

Selection should consider:

Pneumatic Actuators

Pneumatic actuators use compressed air to generate rotary or linear movement. They are commonly selected where fast operation, frequent cycling, and reliable automatic valve operation are required.

Common Pneumatic Configurations

• Double-Acting

• Spring-Return

• Rack & Pinion

• Scotch-Yoke

• Linear Pneumatic

Double-acting actuators use air pressure for both opening and closing movement, while spring-return actuators use compressed air for one direction and spring force for the return movement.

Pneumatic Actuator Selection

Selection may consider:

• Required Valve Torque/Thrust

• Air Supply Pressure

• Double-Acting or Spring-Return Configuration

• Fail-Open / Fail-Close Requirement

• Operating Speed

• Cycle Frequency

• Ambient Temperature

• Valve Mounting Arrangement

• Hazardous Area Requirements

Electric Actuators

Electric actuators use an electric motor and gear mechanism to generate rotary or linear movement. They are suitable for remote operation, automatic isolation, and modulating applications where electrical power and control systems are available.

Common Electric Configurations

• Multi-Turn

• Part-Turn

• Linear

• On/Off

• Modulating

Electric Actuator Selection

Selection may consider:

• Required Valve Torque/Thrust

• Power Supply

• Operating Time

• Duty Cycle

• Control Signal

• Modulating Requirement

• Manual Override

• Enclosure/IP Rating

• Ambient Temperature

• Hazardous Area Requirements

Materials & Construction

Actuator construction and materials should be selected according to the operating environment and service conditions.

Common construction materials may include:

• Aluminium Alloy

• Carbon Steel

• Stainless Steel

• Ductile Iron

• Engineering Polymer Components, where applicable

Selection may consider:

• Corrosion Resistance

• Ambient Temperature

• Outdoor Installation

• Humidity

• Dust Exposure

• Chemical Exposure

• Required Service Life

Control & Accessories

Pneumatic and electric actuators may be supplied with suitable control and monitoring accessories.

Common accessories include:

• Solenoid Valve

• Limit Switches

• Position Indicator

• Positioner

• Air Filter Regulator

• Pressure Regulator

• Speed Controller

• Junction Box

• Local Control Station

• Manual Override

• Position Transmitter

Accessory selection should be based on actuator type, valve function, control system, hazardous-area requirements, and project specifications.

Operation

Pneumatic and electric actuators may be configured for:

• On/Off Operation

• Open/Close Operation

• Modulating Operation

• Remote Operation

• Automatic Operation

• Local Manual Operation

The actuator may receive control signals from a PLC, DCS, SCADA system, control panel, or other process control equipment.

For safety-critical applications, the actuator may be configured with a defined fail position such as:

• Fail Open

• Fail Close

• Fail in Place, where applicable

Quick Selection Guide

Actuator Type: Select pneumatic or electric actuation according to available utilities, operating requirements, control system, and application.

Valve Type: Confirm the valve type and required actuator mounting arrangement.

Valve Size: Specify DN/NPS and valve operating requirements.

Torque/Thrust: Provide required valve operating torque for rotary valves or thrust for linear valves.

Operation: Define whether the actuator is required for on/off or modulating service.

Pneumatic Supply: For pneumatic actuators, provide minimum, normal, and maximum air supply pressure.

Power Supply: For electric actuators, specify available voltage, phase, and frequency.

Control Signal: Specify on/off, modulating, 4–20 mA, or other required control signal.

Fail Position: Define Fail Open, Fail Close, or Fail in Place where applicable.

Operating Speed: Specify required opening/closing time or linear stroke speed.

Duty Cycle: Provide expected operating frequency and required duty cycle.

Installation: Confirm actuator mounting arrangement and valve orientation.

Environmental Conditions: Specify ambient temperature, humidity, dust, corrosion, and outdoor installation requirements.

Hazardous Area: Where applicable, specify hazardous-area classification and required explosion protection.

Manual Override: Specify the requirement for manual operation during loss of power or control supply.

Accessories: Define required solenoid valves, positioners, limit switches, position indicators, feedback, regulators, or other accessories.

Testing & Inspection

Depending on project specifications and applicable standards, pneumatic and electric actuators may undergo:

• Functional and operational testing

• Torque/thrust verification

• Stroke and travel verification

• Opening and closing time verification

• Pneumatic pressure testing, where applicable

• Air leakage testing, where applicable

• Electrical functional testing

• Insulation resistance testing, where applicable

• Control signal verification

• Limit switch testing

• Position feedback testing

• Manual override testing

• Dimensional inspection

• Visual and surface inspection

• IP/enclosure verification, where applicable

• Explosion-protection certification verification, where applicable

• MTC verification, where applicable

Applications

Pneumatic and electric actuators are commonly used in:

• Oil & Gas

• Refineries

• Petrochemical Plants

• Chemical Plants

• Power Plants

• Water Treatment

• Wastewater Treatment

• Steam Systems

• Boiler Systems

• Process Automation

• Process Piping

• Pipelines

• Pumping Systems

• Gas Distribution Systems

• HVAC Systems

• Utilities

• Industrial Plants

Engineering Inputs for RFQ

For technical enquiry and quotation, provide:

Actuator Type • Rotary/Linear Configuration • Valve Type • Valve Size • Required Torque/Thrust • Valve Function • Pneumatic Supply Pressure, where applicable • Power Supply, where applicable • Control Signal • Fail Position • Operating Speed • Duty Cycle • Valve Mounting Arrangement • Ambient Temperature • Enclosure/IP Rating • Hazardous Area Classification, if applicable • Manual Override • Required Accessories • Installation Orientation • Testing & Inspection Requirements

Manufacturer Brands

1. ZOLOTO — Industrial Valves

Brand: ZOLOTO
Website: www.zolotovalves.com

2. MARCK — Industrial Valves

Brand: MARCK
Manufacturer: Hawa Engineers Ltd.
Website: www.marckvalves.com

3. LEHRY — Industrial Valves and Instrumentation

Brand: LEHRY
Manufacturer: Lehry Instrumentation & Valves Pvt. Ltd.
Website: www.lehryvalves.com

4. UFLOW — Automation and Process Control Valves

Brand: UFLOW
Manufacturer: Uflow Automation India
Website: www.uflowvalve.com

5. V-TORK CONTROLS — Industrial Flow Control Valves

Brand: V-TORK CONTROLS
Website: www.vtorkcontrols.com

6. PENNANT — Steam Traps and Pipeline Accessories

Brand: PENNANT
Manufacturer: Pennant Engineering Pvt. Ltd.
Website: www.pennantcorp.com