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Woodward 9907-996
Product Name: LQ25 Liquid Fuel Control Valve (0.3 in² port configuration)
Product Overview: The Woodward 9907-996 is a member of the LQ25 series of fully electronic liquid fuel metering valves, designed for industrial and aeroderivative gas turbines in the 10,000–42,000 kW power range. It integrates a brushless DC motor, rotary shear-meter valve, and non-contact position feedback into a single compact, all-electric assembly, eliminating hydraulic power units and associated leak risks.
Detailed content
Key Technical Specifications:
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Metering Port Area: 0.3 in² (194 mm²)
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Maximum Fuel Flow: 16,000–26,000 lb/h (7,258–11,794 kg/h) at specific gravity 0.77
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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 Differential Pressure: 50 psid (345 kPa)
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Minimum Metered Flow: 80 lb/h (36 kg/h)
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Turndown Ratio: >100:1
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Driver: 8200-314 digital driver
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Command / Feedback Signal: 4–20 mA
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Drive Voltage: 18–32 VDC
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Full-Stroke Time: <100 ms
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Metering Accuracy: ±5% of nominal flow or ±0.5% of maximum rated flow (whichever is greater)
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Weight: approx. 86.4 kg (190.5 lb)
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Nominal Bore: 29.2 mm (1.15 in)
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Ingress Protection: IP64
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Operating Temperature: –28 °C to +85 °C
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Storage Temperature: –40 °C to +103 °C
Functional Features: Equipped with a Pressurizing Valve (PIV) and a 24 VDC Solenoid Operated Shutoff Valve (SOV) for low-flow boost and emergency fuel cutoff. The patented single-stage droop-compensated differential pressure regulator holds the metering-port ΔP constant. Self-cleaning shear-action metering resists contamination. Three-speed frameless resolver (7 VAC @ 4,000 Hz, 36–49 Ω) provides high-resolution position feedback.
Materials & Structure: Stainless steel valve body and wetted components (marine-compliant version available); hardened corrosion-resistant alloy metering plate; FKM seals; aluminum or stainless structural parts. Rotary valve plate is directly coupled to the brushless DC motor rotor.
Working Principle: The remote driver receives a 4–20 mA position command, drives the brushless DC motor to rotate the metering plate, changing the effective area of the metering port. The internal ΔP regulator maintains 50 psid across the port so that output flow is a deterministic function of port area alone.
Installation Requirements: Install downstream of a positive-displacement fuel pump with an upstream filter (≤20 µm). Upstream fuel must contain ≤0.1% volume water and ≤1.0 mg/L solid sediment. Use shielded cable, single-point grounded. Mount rigidly to a bracket using standard bolt holes; keep the driver within 100 m of the valve.
Application Scenarios: Large-frame power-generation gas turbines, high-power mechanical drives, and marine propulsion systems requiring 16,000–26,000 lb/h fuel flow with high dynamic response.
Usage Precautions: Verify fuel filtration before start-up. Periodically check resolver wiring and shield integrity. Never operate beyond the rated temperature envelope. Cut fuel supply and confirm zero pressure before any maintenance.
