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Woodward 8915-708
Product Name
3103 Gas Valve with TM-55 Actuator (3103/TM55 configuration).
Product Introduction
The 8915-708 is a Woodward configured package of the 3103 stainless steel rotary gas metering valve with a TM-55 electro-hydraulic integrating actuator, supplied as a matched and factory-calibrated valve/actuator assembly for industrial gas turbine fuel metering from light-off to full load.
Detailed content
Technical Specifications
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Valve type: 3103 rotary sleeve-and-shoe throttling gas valve
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Actuator type: TM-55 electro-hydraulic integrating actuator
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Metered fuel: natural gas, propane, ethane, methane
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Fuel specific gravity: 0.5 to 1.05
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Gas flow range: 23 to 18 144 kg/h (50 to 40 000 lb/h) based on 0.6 sp gr
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Inlet pressure: up to 5861 kPa (850 psig) per current Woodward 3103 manual; up to 6206 kPa (900 psia) in earlier published data; 4964 kPa (720 psia) maximum under CE marking restriction
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Differential pressure: 172 to 5861 kPa (25 to 850 psig)
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Fuel temperature: -40 to +149 °C (-40 to +300 °F)
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Actuator hydraulic supply pressure: 2758 to 8274 kPa (400 to 1200 psig)
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Actuator operating temperature: -40 to +121 °C (-40 to +250 °F)
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Actuator input signal: ±200 mA integrating
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Accuracy: ±5% of point, or ±0.25% of maximum flow, whichever is larger; ±2% of point at stops
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Hydraulic fluid: mineral or synthetic based oil, diesel fuel, kerosene, gasoline, or light distillate fuel
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Recommended viscosity: 6.0 to 400 cSt (150–200 SSU; ISO 32 grade)
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Hydraulic cleanliness: ISO 4406 20/18/15 minimum
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Supply filter: 40 μm nominal; external filtration 10 μm nominal required
Features
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Self-cleaning metering structure for sour gas service
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Through-hardened stainless steel internal parts
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Inlet guide tube minimizes contaminant accumulation
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Internal mechanical feedback for good open-loop accuracy
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Optional electrical position transducer
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Dual-coil redundant torque motor option
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Fail-safe bias toward minimum fuel on loss of supply pressure or input current
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Adjustable flow stops and minimum position indicator switch
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UL Listed and CSA Certified
Application Scenarios
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Industrial gas turbine generator sets
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Gas turbine driven compressors
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Combined heat and power (CHP) systems
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Mechanical drive gas turbines
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Sour gas / high sulfur fuel environments
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Offshore and marine gas turbine packages
Performance Parameters
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Minimum actuator slewing time: 100 ms; time constant: 25 ms
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Shearing force at sleeve outer diameter exceeds 1334 N (300 lb)
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Flow turndown ratios up to 500:1
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Maximum flow capacity depends on available gas conditions
Material Composition
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Valve body: stainless steel
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Internal parts: through-hardened stainless steel
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Seals: Viton (FKM) or other fuel-compatible elastomer
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Actuator case: anodized aluminum
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Preformed packing ring isolates hydraulic fluid from torque motor
Structural Characteristics
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Rotary sleeve-and-shoe metering structure
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Two standard port configurations: 645 mm² (1 in²) and 1290 mm² (2 in²) maximum flow area
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Actuator: torque motor servovalve + spring-centered four-land spool valve + double-acting servo piston
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Metering sleeve support bearings positively sealed from gas
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Two overboard drains on the valve body
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Valve angle indicator furnished
Working Principle
The electronic control energizes the TM-55 torque motor servovalve. The torque motor produces a differential pressure that drives the second-stage spool valve, routing hydraulic oil to either side of a double-acting servo piston. The piston rotates the output shaft to position the 3103 rotary metering sleeve, changing the effective port opening. An internal electrical position feedback transducer closes the loop. On loss of hydraulic supply or electrical input, the actuator spring biases the valve to the minimum fuel position.
Installation Requirements
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Handle with care; abuse can damage seals, installation surfaces, and factory adjustments
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Keep plastic shipping caps on hydraulic and gas connections until piping is complete
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Provide a 10 μm (nominal) filter in the hydraulic supply line; maintain ISO 4406 20/18/15 cleanliness
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Use a pressure switch to confirm correct hydraulic supply pressure before start-up and continuously thereafter
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Plumb one overboard drain outside the turbine enclosure; plug the unused drain (do not plug both)
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Installation attitude does not affect actuator performance
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The TM-55 is factory calibrated and drained; no additional cleaning or calibration required before installation
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Prime mover must be equipped with an independent overspeed shutdown device
Usage Precautions
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Maintain strict hydraulic fluid cleanliness; contamination directly affects actuator life
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Solid particle contaminants: <10 μm diameter ≤ 30 ppm by volume; >10 μm diameter ≤ 0.3 ppm by volume
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No field disassembly of the TM-55 actuator or 3103 valve; Woodward recommends factory service or authorized overhaul
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Observe ESD precautions when handling electronic components
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In hazardous (classified) areas, wiring must comply with applicable regional electrical codes
