LPC Pneumatic Compact Scotch-Yoke Actuator

Limitorque, LPC, Compact, Scotch-Yoke, Pneumatic Actuator, Acrodyne, piston type, cast iron housingManufacturer: Limitorque

Group: Pneumatic Actuator
The Limitorque Pneumatic Compact (LPC) Scotch Yoke is a robust yet lightweight, modular, pneumatic, piston-type actuator design, with nodular cast iron housing and carbon steel ENP cylinders that is exclusively distributed to both Australia and New Zealand by Acrodyne. LPC pneumatic actuator is available in both spring-return and double-acting configurations, with easy field conversion feature from Fail Close CW to Fail Open CCW. With a maximum allowable working pressure of 12 barg (174 psig), it is ideally suited for smaller size valves and those requiring less than 1600 Nm (1180 ft-lb) of maximum output torque. The LPC is fully complementary to the LPS, employing a similar design philosophy and meeting the same industry specifications, but in a more compact, lower cost package.


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Nuclear Power, Oil and Gas, Water Handling and Treatment, Power Generation, Steam Systems, Chemical Processing


ISO 9001, EN 15714
LPC actuator is suitable for use in on/off, modulating and control applications of quarter-turn valves in general service and protective services. It can also be used in safety services such as emergency shutdown (ESD) or high-integrity pressure protection systems (HIPPS), up to and including SIL 3 Level in accordance with IEC 61508. Among the most important benefits of this product:

  • Industry-leading, 25-year design life, depending on service conditions, proper installation, operation and maintenance.
  • Maintenance intervals up to five years, for most applications, or as prescribed in EN 15714 for high-cycle applications
  • Warranty terms exceeding typical industry norms
  • Modular construction to reduce initial cost, minimize repair cost and maximize process availability
  • Maximum allowable working pressure (MAWP): 12 barg (174 psig)
  • Torque range up to 1600 Nm (1180 ft-lb); contact factory for larger sizes
  • -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)
  • Quick stroking times — less than 0.5 seconds, subject to technical evaluation
  • Spring Return Single Acting (Fail Close CW and Fail Open CCW) and Double Acting (Fail Last / Fail-as-is) executions
  • Symmetrical and Canted Scotch yoke types to perfectly fit valve torque requirement
  • Housing constructed in ASTM A536 60-40-18 Nodular Ductile Cast Iron; different materials of construction upon request
  • Carbon Steel ENP lined Cylinders; Stainless Steel Cylinders, Tie Rods and Spool Pieces available upon request
  • End mounted adjustable travel stops ± 5°
  • Full range of accessories: switchboxes, positioners; ESD and PST functionalities; custom control panels; fire protection; manual and hydraulic overrides
  • Newly developed controls packages for precise torque control and safety functionality

Product Features

Compact design with springs installed on the same side of the cylinder and retained by the piston and piston rod, features a true modular design with modules assembled and tested as separates units. The push-to-compress springs are safely enclosed by tie rods and positively retained on the torque module under all load conditions. The pneumatic cylinder proven and reliable design with external tie rods is suitable for continuous duty service at the maximum rated pressure. The LPC is designed for a maximum allowable working pressure of 12 barg (174 psig), as standard for operation across a full range of applications. Its low displacement design reduces operation and controls package costs. The actuator is available in single-acting spring return (Fail Close CW and Fail Open CCW) and double-acting (Fail Last / Fail as Is) Upon request, available in balanced weight configuration, with cylinder and spring installed on opposite sides of central body (for this option, contact Flowserve).

Reliable scotch yoke design minimizes transverse loads and is suitable for high cycles applications. A symmetrical yoke is standard, and a canted yoke is available optionally. The torque and pressure modules include numerous heavy-duty features, including:
High-strength, heat-treated alloy steel guide bar is hard chrome plated for wear and corrosion protection

Guide block for directional alignment of linear forces, transfer of side loads to the guide bar, and transfer of torque to the yoke

  • High-strength yoke pin for maximum torque transfer while minimizing wear and localized stresses
  • Wear and corrosion protection of all components is ensured with suitable treatments and coatings.
  • Electroless nickel plating is the standard for the internal surface of the pneumatic cylinder to ensure complete sealing and superior corrosion resistance. Other coatings for the internal surface of the cylinder are available upon request.
  • Modular design for flexible and easy field conversion from Fail Close CW to Fail Open CCW configuration or vice versa
  • On-site maintenance without need of special tools

Rapid emergency response in less than 0.5 seconds achieved through optimized design. The LPC is designed with emphasis on ever-increasing requirements for fast response time. The result is the smallest possible displacement volume for given torque outputs, resulting in the fastest possible cylinder exhaust, making it ideal for emergency applications such as EDS and HIPPS.

Standard and Custom Controls

Limitorque offers a wide selection of standard and custom controls packages for most applications to fill customers’ needs for short lead-time, low-cost solutions:

  • Partial Stroke Test (PST)
  • Emergency shutdown (ESD)
  • High-integrity pressure protection systems (HIPPS)
  • Quick-closing
  • Modulating/control valve functionality
  • Quick exhaust valve with flow regulator for closed loop
  • Cylinder integral quick-exhaust valve
  • Pneumatic booster
  • 3/2 and 5/2 pneumatic piloted valve with manual reset and override
  • Unidirectional and bidirectional flow regulator valves
  • Compact fittings to reduce pipe and controls dimensions
  • Lockout modules, manual overrides, other controls and accessories are available.

PDF Downloads

LPS LPC Product Flyer (656 kb)

Limitorque Pneumatic Compact Scotch Yoke Actuator LFENFL002-00-A4 (LPC)

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