​The Limitorque LPS heavy-duty pneumatic scotch yoke actuator is the innovative, reliable choice  for on/off, inching and modulating automation applications on quarter-turn medium-to-large sized valves in general and protective services for the oil & gas market.

With an operational design life of 25 years and a maintenance interval up to six years*, the LPS is setting new standards for heavy-duty pneumatic actuators and resetting industry expectations. Equipment performance and safety standards continue to evolve and increase across the infrastructure industries. These stringent demands are particularly dynamic in oil and gas, where perpetually increasing emphases on personnel safety and equipment uptime is the norm. To more aggressively meet these demands, Flowserve Limitorque is offering the LPS pneumatic Scotch yoke actuator - specifically designed to meet or exceed the latest and most rigorous of these requirements.

Features and Benefits:

• True modular design permits the flexibility of configuring the actuator in either CW or CCW/fail open or fail close configurations as needed, including in the field, if necessary.

• Fabricated carbon steel center body, pressure module and spring module provide the most rugged actuator available; alternate materials designed for polar or offshore applications available upon request.

• Suitable for use in on/off, modulating and control valve application in general service, protective service and safety applications such as ESD or HIPPS.

• Available in standard single-acting spring return and doubleacting configurations, in torque ranges up to 300 kNm (221 270 ft-lb); contact factory for larger sizes.

• 12 bar (174 psi) maximum allowable working pressure (MAWP).

• -60°C (-76°F) to 160°C (320°F) operating temperature range in several configurations (suitable for polar, cold, temperate, arid and tropical requirements in accordance with IEC 60721).

• Suitable for use in safety integrated systems up to and including SIL Level 3 in accordance with IEC 61508.

• Full range of accessories: switchboxes; positioners; ESD, PST and line-break functionality; custom control panels; fire protection; manual and hydraulic overrides.

• Symmetrical and Canted scotch yoke types to perfectly fit valve torque requirement.

• End mounted adjustable travel stops ± 5°, available also in an enclosed protected version upon request Key Certifications and Standards Compliance.

• Certified according to ATEX 94/9/EC Ex II 2GD c IIC T6

• IP66/IP66M and IP67/IP67M configurations per EN 60529

• SIL 3 certified in accordance with IEC 61508.

• Available in compliance with PED 97/23/EC, ASME BPVC Sec. VIII Div. 1, EN 13445-3 Part 2 for Unfired Pressure Vessels.

• NEMA4 and NEMA4X per NEMA 250.

• Available valve interface in compliance with ISO 5211.

• Actuator spring design in compliance with EN 13906.

• Corrosion protection in compliance with ISO 12944-2 and EN 15714-3; optionally available up to and including C5-M.

• Available in compliance with NACE specification MR0175 for sour gas applications.

• Manufactured and tested in compliance with ISO 9001 and EN 15714-3.

• Available according to CU TR and GOST-R


​​The Limitorque LPC Compact Pneumatic range is a robust, lightweight, modular Scotch yoke design available in both spring return and double acting configurations. It is suitable for actuating ball, butterfly and plug valves or any other quarter-turn application. LPC compact actuators deliver up to 1600 Nm* (1180 ft-lb) of precisely controlled torque. The LPC product range is complementary to the Limitorque LPS heavy-duty pneumatic Scotch yoke actuators. A similar design philosophy to the heavy-duty LPS was applied to the new LPC range, delivering enhanced performance and high reliability. The LPC is available in standard as well as special material configurations upon request. LPC actuators are complemented by a comprehensive range of control systems, including ESD, PST and Quick Closing options. A suite of standard controls systems is available for short delivery, but the Limitorque engineering team can design custom solutions for the largest and most complex customer requirements.


• Torque range up to 1600 Nm (1180 ft-lb)**
• Maximum allowable working pressure (MAWP): 12 barg (174 PSIG).
• -29°C to 100°C (-20°F to 212°F) standard operating temperature range; Low temperature -60°C (-76°F) and high temperature 160°C (320°F) ranges available upon request (polar, cold, arid and tropical temperature requirements in accordance with IEC 60721).
• End mounted adjustable travel stop ± 5°, available also in an enclosed protected version upon request.


The Limitorque LRP series provides durable functionality and prolonged service life through unique features such as piston support rods within the actuator, ensuring that side loads generated by the pistons are transmitted through bearings in the end cap and not the body. This eliminates the need for the body to be used as a loadbearing surface and promotes longer service life. The support rod design of the Limitorque LRP actuator distinguishes it from the standard rack and pinion design and offers reliable operation, performance stability and longer service life. In addition to offering improved operational safety and ease of maintenance, the modular LRP design provides greater application flexibility for easy fitting and interchangeability of ancillary equipment, making it one of the finest pneumatic actuators available today.

Key Benefits:

• Balanced double rack and pinion provides a linear torque curve with a large range of sizes for efficient torque matching.

• Mounting to ISO 5211 pattern and DIN 3337 female star drive provides common and simple actuator to valve attachment.

• Position indicator - provides highly visible external indication of valve position.

• Foolproof location pin for correct assembly.

• Multi-spring concept - allows variable torque/air pressure requirements from the same actuator by changing spring quantity.

• Namur VDI/VDE 3845 top mounting pattern - for easy fitting and interchangeability of switches, positioners, etc.

• Namur VDI/VDE 3845 end-cap solenoid mounting pattern - facilitates interchangeability of solenoids or direct port connections.

• Compact fail-safe size as per double-acting - minimizes space requirements, rReduced maintenance and Longer Service life.

• Anodised aluminium construction - for anti-corrosion and superior wear performance on internal surfaces, plus stainless steel fasteners and corrosion-protected springs.

• One piece steel pinion drive with full width piston tooth engagement - for greater operational life, increased plant and personnel safety.

• For fail-safe operation in a fire, polished support rods retain fire-safe capability even if bearings are fire damaged.

• Blow-out proof pinion - eliminates risk of pinion ejection even after pinion retaining ring is removed.

• Unique unrestricted air flow through support rods gives fast operation speeds as standard - and also provides greater safety (center chamber cannot be pressurized with end cap removed).

• Long end cap screws allow complete release of spring energy for safe removal of end caps.