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Woodward 9908-410

Product Name:​ LQ25 Series Standard Liquid Fuel Metering Valve
Product Introduction:​ This model serves as the fuel metering interface between electronic engine control systems and gas turbines, designed for industrial and aeroderivative gas turbines in the 1000 kW to 42000 kW power range. It adopts a fully electric actuator to achieve precise fuel flow regulation through a standard 4–20 mA signal.

Detailed content

Technical Specifications:
  • Applicable power range: 1000 kW to 42000 kW
  • Maximum fuel inlet pressure: 1200 psig (8274 kPa)
  • Maximum fuel bypass pressure: 100 psig (690 kPa)
  • Rated metering differential pressure: 50 psid (345 kPa)
  • Fuel filtration accuracy: 20 microns or finer
  • Fuel water content limit: 0.1% by volume
  • Solid sediment limit: 1.0 mg/L
  • Minimum metering flow: 36 kg/h (80 lb/h)
  • Flow turn-down ratio: greater than 100:1
  • Operating temperature range: -28 °C to +85 °C
  • Storage temperature range: -40 °C to +103 °C
  • Valve body weight: approximately 35 kg (77 lb)
  • Nominal pipe diameter: 29.2 mm (1.15 in)
  • Protection class: IP66
  • Drive power supply: 18 to 32 VDC
  • Command signal: 4 to 20 mA
  • Valve position feedback signal: 4 to 20 mA
Functional Features:
  • Rotary plate metering structure with single moving part for high reliability
  • Non-contact position sensor with no mechanical wear and long service life
  • Rare-earth permanent magnet actuator with high torque density and fast response
  • Remote shut-off command input supporting emergency stop
  • Valve/driver fault output for easy system diagnostics
Application Scenarios:​ Liquid fuel control for gas turbine generator sets, industrial mechanical drive, and marine propulsion systems. Handles diesel, kerosene, gasoline, and other compliant liquid fuels.
Performance Parameters:​ Flow metering accuracy is ±5% of actual flow or ±0.5% of maximum flow. Full-stroke actuation time is less than 100 ms, meeting the rapid load change demands of gas turbines.
Material Composition:​ Wetted parts are made of corrosion-resistant alloy materials; sealing components use fluorocarbon rubber (FKM); the overall structure resists fuel corrosion and high-temperature aging.
Structural Features:​ Uses a single-speed frameless resolver as the position feedback element, with resolver excitation parameters of 4 VAC, 5000 Hz, and resistance of 28 to 34 ohms (at 20 °C). The valve body is compact, and the electrical interface adopts a standard terminal block design.
Working Principle:​ The electronic driver unit converts the 4–20 mA control signal into motor drive current. A limited-angle torque motor drives the rotary valve plate to the target position. Precision EDM-formed flow passages in the metering port ensure an accurate correspondence between flow and input signal. A built-in differential pressure regulator automatically maintains a constant differential pressure across the metering port, eliminating the influence of system pressure fluctuations on metering accuracy.
Installation Requirements:
  • Install in the gas turbine fuel supply main line, with the inlet connected to the outlet of a positive displacement pump
  • Use compliant fasteners for valve body fixation, with torque executed per specification
  • Single-point grounding for electrical shielded cable to prevent electromagnetic interference
  • Reserve sufficient maintenance space for periodic inspection
Usage Precautions:
  • Strictly prohibit use of unfiltered fuel; particulates will accelerate metering port wear
  • Before first start-up after prolonged shutdown, check driver parameters and valve flexibility
  • Pneumatic noise is generated during operation; on-site personnel must wear hearing protection
  • Storage temperature must not exceed the specified upper limit to prevent seal aging

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