Scotch Yoke Pneumatic Actuator

RTQ single/double acting pneumatic actuators, are suitable for the operation of quarter turn valves (ball valves, butterfly valves and plug valves) for on-off and modulating heavy-duty service.

The actuator is made up of a waterproof scotch yoke mechanism transforming the linear movement of the pneumatic cylinder (on closing or opening) into the rotary movement, which is necessary for valve operation. Scotch yoke mechanism centerbody cover is machined to provide the assembly pattern for any required accessories (for example positioner, signaling limit swiches, etc.) by mean of proper matching units. The above mentioned accessories are operated by the actuator drive sleeve.

Actuator centerbody bottom wall is machined with threaded holes to allow actuator mounting on top of valve top-work either directly or, when required, with the interposition of an adaptor flange or a mounting bracket. The travel stroke is adjustable between -4 deg/+4 deg at both ends by mean of the external mechanical stops arranged into the side-wall of the mechanism body and into the end flange of the pneumatic cylinder.


  • Chromium plated guide bar to absorb transversel forces
  • Designed to provide high torque with minimum space and weight
  • Double acting or spring return compact design
  • Electroless nickel plated cylinder to minimise friction and prevent corrosion
  • Full stainless steel version available
  • Housing is manufactured in carbon steel material without any cast/grey/ductile iron or aluminum parts
  • Integral or declutchable manual hand-wheel available
  • Scotch yoke mechanism available in both canted or symmetrical executions
  • SHELL Endurance Test approved
  • Totally sealed weatherproof housing that provides complete protection for all moving parts

Technical data

Operating pressure

Pneumatic version up to 12 barg

(special version available on request)

Standard operating temperature

-30°C to 100°C

(lower or higher temperature on request)

Output torque

From 2.000 Nm up to 600.000 Nm

(for double acting version)

Spring Ending Torque

From 1.650 Nm up to 165.000 Nm

(for single acting version)


PED 2014/68/EU

ATEX 2014/34/EU 

EAC TR TS 012/2011 


IP66/67M according to IEC/EN 60529 

SIL3 certified (IEC 61508) as a “single device”

Designed and tested in accordance with EN 15714-3

(further certifications are available, please contact us for updated list)

Contact us for more information