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Woodward 9908-405
Product Name: LQ25 Liquid Fuel Metering Valve (Standard Configuration)
Product Overview: 9908-405 is a standard-configuration LQ25 liquid fuel metering valve serving gas turbines in the 1,000–42,000 kW range. It provides a reliable fuel-metering interface between the electronic engine control system and the gas turbine.
Detailed content
Key Technical Specifications:
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Applicable Power Range: 1,000–42,000 kW
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Maximum Fuel Inlet Pressure: 1,200 psig (8,274 kPa)
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Maximum Fuel Bypass Pressure: 100 psig (690 kPa)
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Nominal Metering ΔP: 50 psid (345 kPa)
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Minimum Metered Flow: 80 lb/h (36 kg/h)
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Fuel Filtration: ≤20 µm
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Water Content: ≤0.1% by volume
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Solid Sediment: ≤1.0 mg/L
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Turndown Ratio: >100:1
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Metering Accuracy: ±5% of nominal flow or ±0.5% of max flow
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Full-Stroke Time: <100 ms
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Emergency Shutoff Response: <50 ms
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Drive Voltage: 18–32 VDC
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Command / Feedback: 4–20 mA
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Weight: approx. 35 kg (77 lb)
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Nominal Bore: 29.2 mm (1.15 in)
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Ingress Protection: IP66
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Operating Temperature: –28 °C to +85 °C
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Storage Temperature: –40 °C to +103 °C
Materials & Structure: Corrosion-resistant alloy or stainless-steel wetted parts; FKM seals. Frameless single-speed resolver (excitation 4 VAC @ 5,000 Hz). Compact valve body, terminal-block electrical interface.
Working Principle: Remote driver receives 4–20 mA control signal, drives limited-angle torque motor to rotate the metering plate, changing effective flow area. Internal ΔP regulator automatically maintains 345 kPa across the metering port, so output flow correlates only with port opening for precise fuel metering.
Installation Requirements: Must be installed downstream of a positive-displacement pump; bypass return line must remain clear. Use specification-compliant fasteners tightened to prescribed torque. Shielded cable single-point grounded to prevent EMI. Mount in a location convenient for routine inspection.
Application Scenarios: Widely used in gas-turbine power generation, mechanical drive, and marine propulsion liquid-fuel systems. Compatible with diesel, JP-series aviation fuel, kerosene, gasoline, and standard-compliant distillate fuels.
Usage Precautions: Fuel filtration must reach ≤20 µm to prevent metering-port wear. Regularly inspect electrical-connection tightness and cable insulation integrity. Wear hearing protection—the valve body generates aerodynamic noise during operation. Avoid severe impact during storage and transport to protect the resolver and actuator.
