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Pitch Cylinder


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This pitch cylinder series is the core actuator of the hydraulic pitch system in large wind turbines. Mounted on the rotating cylinder base inside the hub, it precisely rotates the blades around their longitudinal axis via hydraulic servo control, enabling real-time pitch angle adjustment. Under normal operating conditions, the cylinder fine-tunes the blade angle to optimize aerodynamic efficiency. During extreme gusts or emergency stops, it rapidly feathers the blades to a safe position, achieving aerodynamic braking. Designed with a compact structure, ultra-low-friction long-life sealing, and full-lifecycle maintenance-free operation, it performs reliably over the turbine's entire 20+ year service life in the extreme conditions found at the tower top — temperature extremes, continuous vibration, salt spray, and high humidity.

Brand:
PAZON

Pitch Cylinder Hydraulic Cylinder Hydraulic Cylinder Wind Turbine Pitch Control

Product Description

Bore diameter: Φ100mm – Φ220mm
Rod diameter: Φ60mm – Φ150mm
Stroke: 150mm – 600mm (per pitch mechanism geometry and blade angle range)
Operating pressure: continuous 18MPa, max 25MPa
Max push force: 950 kN (at 25MPa, Φ220mm bore)
Max pull force: 510 kN (at 25MPa, Φ220mm bore with Φ150mm rod)
Breakaway pressure: ≤0.15 MPa (ultra-low friction for sensitive servo response)
Piston velocity: 0.2 – 200 mm/s (from fine inching to full-speed emergency feathering)
Emergency feathering time: ≤3 seconds (full-stroke rapid shut-down)
Operating frequency: continuous micro-adjustment, thousands to tens of thousands of cycles daily
Dynamic response: follows pitch commands from 0.1–5 Hz
Internal leakage: ≤0.01 ml/min (at 18MPa, over full seal service life)
Static holding: ≤1 mm piston drift over 48 hours under full-load feathering
Temperature range: -30℃ to +80℃ (standard); -40℃ to +100℃ customizable
Suitable for: 1.5MW–15MW onshore and offshore wind turbines

Features & Benefits

High Dynamic Response & Precision Position Control
Low-friction filled PTFE and polyurethane composite seals ensure breakaway pressure as low as 0.15 MPa. Combined with a servo proportional valve and an integrated magnetostrictive displacement sensor (±0.02 mm accuracy), sub-millimeter closed-loop blade angle control is achieved. The cylinder switches seamlessly from fine inching to full-speed feathering with a response lag below 10 ms, ensuring the turbine maintains optimal efficiency and safety margins under turbulent wind gusts.
Compact High-Torque Output Construction
The barrel is forged from high yield-ratio quenched & tempered alloy steel, and the piston rod is a large-diameter thick-walled rod with precision hard chrome plating. Finite-element structural optimization delivers the thrust necessary to overcome the enormous blade root pitch moment, all within the confined hub installation space. Spherical bearings at the clevis connections accommodate blade rotation misalignment and installation tolerances.
Ultra-Long-Life Zero-Leakage Sealing
The main seal employs a hydrolysis-resistant polyurethane and anti-extrusion PTFE composite. The gland front features multiple wipers and a stainless steel scraper ring, effectively blocking high-temperature oil mist, wear debris inside the hub, and external salt spray. The seal design life corresponds to the turbine's 20+ year operational cycle, with internal leakage as low as 0.01 ml/min.
All-Condition Weather & Corrosion Resistance
The cylinder exterior is coated with salt-spray and UV-resistant epoxy fluorocarbon paint. All fasteners are stainless steel. For offshore turbines, the piston rod is available with laser-clad nickel-based alloy or ceramic coating, delivering over 6,000 hours of salt-spray resistance, remaining rust-free in maritime salt spray, humidity, and splash.
Fail-Safe Protection & Accumulator Matching
Working in concert with the hydraulic accumulator, even in the extreme event of grid loss or pump failure, the accumulator releases its stored energy to drive the cylinder and feather the blades to the safe position within 3 seconds, achieving reliable aerodynamic braking and preventing over-speed runaway.
Complete International Certifications
Designed and manufactured to meet PED, ASME, NR13, and other international codes, with third-party type approval and full material traceability available, satisfying global wind farm access requirements.
Maintenance-Free & Intelligent Monitoring
Self-lubricating spherical bearings are standard at clevis connections, requiring no grease and lasting through the turbine's overhaul cycle. Built-in displacement sensors and cylinder pressure transducers can be integrated to provide real-time pitch condition monitoring and predictive maintenance alerts via the turbine SCADA system.