SFG240X204D187 Servo Valve: Technical Features and Application Guide
I. Product Overview
The SFG240X204D187 Servo Valve is a high-precision electro-hydraulic component specifically engineered for variable pitch axial fans. Its primary function is to receive milliampere-level (mA) electrical signals from the unit control system and convert them into modulated hydraulic flow and pressure. This output drives the hydraulic cylinder and actuators to achieve real-time, precise adjustment of the fan blade angles.
To form a complete control loop, this servo valve operates in coordination with actuator components like the Cylinder Linkage TY98010, Spindle UZ22010, and connection hardware such as the Blade Bolt DYL2420-75. As a critical spare part for the flue gas and air systems, its performance stability directly impacts the fan's ability to adapt to boiler combustion conditions.
One-Stop Spare Parts Solution
We provide a comprehensive range of compatible seals and auxiliary components to ensure risk-free replacement and reduced procurement costs:
| Component Category | Model / Part Number | Description |
| Main Servo Valve | SFG240X204D187 | Core electro-hydraulic control unit |
| Sealing Elements | Laminated Seal U184D11 | High-pressure static/dynamic sealing |
| Scraper Rings | TY9102C (Type I), TY9111C (Type II) | Prevents external contamination |
| Blade Seals | O-Ring U3719G2108Y02-O | Specialized blade root sealing |
| Composite Seals | U3518G2108Y010 | Blade assembly combination seal |
II. Technical Features & Advantages
1. High-Precision Electro-Hydraulic Conversion
The valve features exceptional signal conversion accuracy. It translates weak electrical signals into high-power hydraulic energy with superior linearity.
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Hysteresis Control: Managed within <3%, significantly better than industry standards, eliminating lag in blade adjustment.
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Sensitivity: High pressure gain allows the valve to respond to minute signal changes near the null position, enabling "fine-tuned" control of the fan pitch.
2. Low Leakage & Extended Service Life
Internal leakage is a critical metric for assessing wear. The SFG240X204D187 utilizes a precision-fitted spool and sleeve assembly.
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Efficiency: Minimal null leakage improves hydraulic energy utilization and reduces oil temperature rise.
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Durability: Core components are manufactured from high-strength, wear-resistant alloys with specialized surface treatments to withstand harsh industrial environments.
3. Wide Temperature Range & Environmental Resilience
Designed for the extreme conditions of power plants, this valve maintains stability across a broad thermal spectrum.
| Feature | Specification / Capability |
| Operating Temperature | -20 ℃ to +80℃ |
| Application Environments | Extreme cold (Northern regions) to high heat/humidity (Southern regions) |
| Contamination Tolerance | High resistance to hydraulic oil impurities |
4. Seamless OEM Compatibility
The SFG240X204D187 is fully compatible with existing fan hydraulic and control systems. It allows for "drop-in" replacement of old valves during maintenance, significantly shortening downtime and preventing power generation losses.
III. Application Scenarios
1. Routine Maintenance & Condition Monitoring
During scheduled inspections, the valve's flow characteristics, internal leakage, and pressure gain are monitored. If parameters deviate from the standard, the valve should be replaced to maintain fan efficiency.
2. Fault Repair & Troubleshooting
If the fan exhibits pitch adjustment jamming, angle deviations, or slow response, the servo valve is the primary component for inspection.
Case Study: In a maintenance project for a HU26246-551G induced draft fan, the replacement of the SFG240X204D187 and the U184D11 laminated seal successfully resolved boiler negative pressure fluctuations caused by adjustment lag.
HKZX-2026-01-26
