1. Product Description

G771K200A H19FOFA4VH4R is an explosion-proof two-stage mechanical feedback servo valve from MOOG G771 series, manufactured in USA for hazardous industrial environments.

Model Code Definition: - G771: Base series two-stage servo valve with double nozzle-flapper pilot stage - K: Explosion-proof intrinsically safe construction for flammable gas & dust zones - 200A: Standard flow rating, rated flow 10 L/min (2.5 gpm) at 35bar pressure drop - H19FOFA4VH4R: Full custom configuration code covering coil specification, sealing material, port layout, null adjustment, electrical connector and explosion-proof certification grade

Core Technical Specifications: 1. Structure: Dry torque motor + double nozzle-flapper pilot stage + mechanical feedback spool 2. Max Operating Pressure: 210 bar (3000 psi) for P/A/B/T ports 3. Rated Flow: 10 L/min @ ΔP=35 bar per spool land; Max flow 17 L/min 4. Step Response: 4ms for 0~100% full stroke; Bandwidth up to 150Hz at -90° phase lag 5. Static Performance: Hysteresis ＜0.3% full scale, ultra-low dead band, high resolution 6. Weight: 0.86kg, ISO 10372 standard mounting surface 7. Sealing: FKM fluorocarbon high-temperature & oil-resistant seals 8. Operating Temperature: -40℃ ~ +120℃, 30g anti-vibration & anti-shock capability 9. Electrical: Analog current signal input, reverse polarity protection, intrinsically safe coil design 10. Safety: Explosion-proof certification for Class I/II hazardous working areas

2. Core Product Functions

• High Precision Electro-Hydraulic Flow Modulation Converts analog DC control current signals into proportional hydraulic flow output to control hydraulic cylinder position, movement speed, output force or system pressure with micro-level accuracy.
• Ultra-Fast Dynamic Response Control Wide bandwidth and short step response enable real-time high-speed closed-loop adjustment, eliminating lag during rapid load variation for high-performance hydraulic servo systems.
• Explosion-Proof Intrinsically Safe Operation K-series explosion-proof torque motor and sealed internal structure prevent electric spark ignition, safe for oil & gas, chemical and power plant hazardous zones with flammable medium.
• Dual Nozzle-Flapper Pilot Stage & Mechanical Feedback Low-friction pilot design delivers stable spool driving force; built-in mechanical feedback eliminates drift, maintains consistent control accuracy under long continuous operation.
• Strong Anti-Pollution & Long Service Life Dry torque motor separates magnetic components from hydraulic oil, avoiding contamination failure; replaceable pilot filter blocks fine oil impurities to protect internal nozzle-flapper components.
• Field Adjustable Null Bias & Fail-Safe Zero Position On-site zero offset calibration without disassembly; valve spool automatically returns to neutral shut-off position when electrical control signal is lost to avoid equipment runaway risk.
• Multi-Parameter Closed-Loop Control Support Compatible with position, velocity, pressure and force closed-loop control algorithms, matching industrial PLC, turbine control systems and hydraulic test benches.
• Harsh Environment Adaptability High/low temperature resistance, anti-vibration, anti-impact and oil corrosion resistance, stable operation under high-pressure heavy-load industrial conditions.

3. Typical Application Scenarios

• Gas & Steam Turbine Power Generation Units Combustion fuel gas flow regulation, valve actuator position control for thermal power combined cycle plants.
• Oil & Gas Offshore & Onshore Equipment Drilling rig hydraulic servo systems, pipeline pressure control, compressor actuator control in explosive hazardous zones.
• Chemical Plant Reaction Furnace & Incinerator High-temperature furnace burner fuel regulation, reactor hydraulic loading & pressure closed-loop control.
• Metallurgical Rolling Mill & Metal Forming Presses Strip tension control, hydraulic press force & position precision servo control.
• Hydraulic Fatigue & Material Test Benches High-frequency dynamic loading control for material tensile, compression and fatigue testing.
• Plastic Blow Molding & Injection Molding Equipment Precision mold clamping and injection speed servo control.
• Aerospace Component Hydraulic Test Stands Aircraft actuator simulation, flight hydraulic system performance verification.

4. Common Faults & Troubleshooting Solutions

5. Import & Compliance Supporting Documents

1. Customs Documents: Certificate of Origin (COO), Factory Certificate of Conformity (COC), Explosion-Proof Certification Report 2. Safety Files: SDS/MSDS for hydraulic valve metal & sealing materials 3. Technical Data: Factory performance test report, calibration curve, dimensional drawing 4. HS Code: 84812010 Electro-hydraulic servo control valves 5. Country of Origin: United States; Gross Weight: ~1.2kg 6. Lead Time: In stock 1~4 working days; OEM factory order 6~10 weeks 7. Matching Spare Parts: Pilot filter element, FKM seal kit, explosion-proof wiring connector, null adjustment tool