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PNEU-TRIP: Steam Turbine Protection Redefined

PNEU-TRIP: Steam Turbine Protection Redefined

PNEU-TRIP, PNEU-TRIP®, steam turbine protection systemApplications

Petroleum refineries and chemical plants utilize general purpose API 611 steam turbines to drive mechanical loads such as pumps, fans, blowers and compressors. Many of these turbines have obsolete and unreliable mechanical overspeed trip devices that pose safety risks to the facility and its personnel. A more reliable overspeed trip solution is now available exclusively from Drake Controls. It includes an electronic overspeed detection device and a pneumatic trip valve actuation system with partial stroke test capability.


The Drake Controls PNEU-TRIP® is a state-of-the-art safety system designed for the protection of steam turbines. Each system includes a SIL-certified pneumatic trip block and SIL capable pneumatic actuator.   When coupled with a Woodward ProTech SX, GII or TPS electronic overspeed detection system, PNEU-TRIP provides the most advanced, safe, high speed and reliable turbine protection solution available.

The system features the patented Partial Stroke Test Device (PSTD) technology that employs a unique pneumatically engaged travel stop for partial stroke testing. While a typical pneumatic trip system falls short in exercising the emergency trip solenoid valves and introduces risk of tripping the turbine during partial stroke tests, the PNEU-TRIP performs a full force partial closure of the trip valve.  This test verifies the integrity of each trip solenoid valve and pneumatic system components. If a turbine trip condition is detected during the test, the travel stop is immediately disengaged allowing to quickly and safely shut the turbine down. PNEU-TRIP components are designed to be fail-safe upon loss of electric or pneumatic power and are online replaceable in TMR configurations.


  • The PNEU-TRIP linear trip valve system is mounted directly on the steam chest. PNEU-TRIP quarter-turn rotary valve system is supplied with a metal seated triple offset butterfly trip valve.
  • Each trip actuation system can be furnished either standalone or as a complete safety solution, integrated with a Woodward electronic overspeed detection device such as ProTech SX or ProTech TPS. PNEU-TRIP also seamlessly integrates with the existing overspeed detection system, such as the ProTech-GII.
  • Complete Turbine Safety Configurations Include:
    • PNEU-TRIP® 212 – simplex logic solver with 1oo2-voted trip solenoid system for safety-critical applications
    • PNEU-TRIP® 332 – triple modular redundant logic solver with 1oo2 voted trip solenoid system for safety-critical and API 670 compliant applications
    • PNEU-TRIP® 333(TMR) – fully fault-tolerant solution with TMR logic solver and 2oo3-voted trip solenoid system for high availability safety applications


  • Complete Replacement of Mechanical Overspeed Trip
  • Fast and Accurate Pneumatic Actuation
  • Seamless Integration with Woodward ProTech Turbine Safety Systems
  • Overall Trip Cycle Time < 150 Milliseconds
  • All SIL-rated Safety System Components
  • Online Partial Stroke Testing at Full Spring Force
  • Online Testable Trip Solenoid Valves
  • Online Replaceable Components (TMR Only)
  • Compact Manifold Holds Redundant Trip SOVs and a PST SOV
  • Fail-Safe and Fault-Tolerant Configurations
  • Linear or Quarter-Turn Actuation Solution Available
  • Pre-Configured & Tested, Requires No Field Assembly Or Configuration
  • No Turbine Disassembly Or New OEM Components Required
  • UL/CSA/FM Approved, Class I, Div. I/II, Groups A,B,C & D Electric Components

Drake Controls’ planned release date for all PNEU-TRIP® models is effective immediately.

To learn more about the features, configurations, and specifications of all models, click here to download our product brochure as featured at the 46th Turbomachinery & 33rd Pump Symposia. To request a custom quote to update your steam turbine protection system into a complete turbine trip system, please email us at sales@drakecontrols.com.


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