Name: Double Acting Pneumatic Actuator
Brand: Supreme Valves India
SKU: pneumatic-actuator-double-acting
Availability: InStock
Rating: 4.8 (82 reviews)

Question 1

What is a double acting pneumatic actuator?

Accepted Answer

A double acting pneumatic actuator uses compressed air to drive the piston in both directions - air pressure extends the piston (opening the valve) and separate air pressure retracts it (closing the valve). This contrasts with spring-return actuators where air opens and a spring provides the closing force. Double acting actuators provide full torque in both directions, making them ideal for applications requiring precise positioning, modulating control, or where spring failure is a concern.

Question 2

How do I size a double acting pneumatic actuator for my valve?

Accepted Answer

Actuator sizing requires the valve breakaway torque, operating air pressure, and safety factor. The general formula: Actuator Torque = Valve Breakaway Torque x Safety Factor (1.3-1.5x) at minimum air pressure. Our standard sizing procedure: obtain the valve's breakaway torque from the valve manufacturer; divide by the torque reduction factor for partial opening if modulating; apply 1.3-1.5 safety factor; select actuator from torque table at your supply pressure. Always verify at minimum system pressure.

Question 3

What is ISO 5211 and why does it matter?

Accepted Answer

ISO 5211 is the international standard defining actuator mounting dimensions: flange size, output shaft diameter and shape, and bolt circle diameter. This standardization means any ISO 5211 compliant actuator can mount to any ISO 5211 compliant valve without custom adapters. Common sizes: F03 (14mm square shaft, ~9-30 Nm), F05 (17mm square, ~40-150 Nm), F07 (22mm square, ~150-400 Nm), F10 (27mm square, ~400-1000 Nm), F12/F14/F16/F25 for larger sizes.

Question 4

What is ATEX certification for pneumatic actuators?

Accepted Answer

ATEX 2014/34/EU is the European Directive for equipment intended for use in potentially explosive atmospheres. Actuators certified ATEX II 2G Ex h IIC T5/T6 Gb are approved for Zone 1 (likely presence of flammable gas) and Zone 2 (abnormal presence) areas. The 'h' code means non-electrical equipment with enhanced safety measures. Key features: anti-static materials, sealed construction, no spark generation. For Middle East oil & gas projects, ATEX certification is often mandatory for actuator procurement specifications.

Question 5

What accessories are needed for a pneumatic actuator installation?

Accepted Answer

Essential accessories for pneumatic actuator installation include: Solenoid Directional Valve (3/2 or 5/2 way) to control air direction; Speed Control Valves (flow control) to adjust opening/closing speed; Air Filter-Regulator-Lubricator (FRL) unit to condition the air supply; Positioner for modulating control; Limit Switch Boxes for remote open/close feedback; and Quick Exhaust Valves for faster cycling. All accessories should be sized to match the actuator port size and air flow requirements.

Question 6

What is the difference between rack & pinion and scotch yoke actuators?

Accepted Answer

Rack & pinion actuators use a gear and toothed piston (rack) mechanism - compact, efficient, and standard for most industrial valve automation (up to 4000 Nm). Scotch yoke actuators use a sliding block in a curved yoke - producing higher initial breakaway force and typically used for larger valves (above 800 Nm) or high-cycle applications like gate valves. Rack & pinion is the preferred choice for ball valves and butterfly valves due to its compact size, efficiency, and lower cost.

Component	Material Specification
Body & Bonnet	Ductile Iron (ASTM A536 / EN-GJS-400-15)
Stem / Spindle	SS 410 / SS 420
Seat / Trim	EPDM / NBR / Bronze

Parameter	Specification / Standard
Manufacturing / Design Standard	EN 1171 / AWWA C509 / BS 5163
Testing Standard	API 598 / EN 12266-1
Pressure Rating	PN16 / PN25

Double Acting Pneumatic Actuator | Rack & Pinion

Key Specifications

Materials of Construction (MOC)

Technical Specifications