Today we introduce application of pneumatic hydraulic rotary union - Wind turbine generator

Application of gas-liquid slip rings in wind turbines

The gas-liquid slip ring is an indispensable core component in wind turbines and is mainly used to solve the medium transmission problem between the blade rotation and the fixed tower. Modern wind turbines usually adopt a horizontal axis design. The blades need to adjust their angles (yaw control) in real time according to the wind direction. At the same time, the hydraulic system inside the generator room needs to continuously provide power to the blade pitch system and braking system. The gas-liquid slip ring assumes the multiple tasks of transmitting hydraulic oil, coolant and electrical signals in this scenario.

Structural and functional features

Gas-liquid slip rings used in wind power generation adopt a modular design and usually integrate hydraulic channels (transmitting high-pressure oil), gas channels (used for cooling or pneumatic braking) and electrical slip rings (transmitting sensor signals and power). For example, in the pitch control system, the hydraulic oil is transmitted to the hydraulic cylinder in the wheel hub through the slip ring to drive the blade angle adjustment; at the same time, the temperature sensor data is transmitted back to the main control system through the electric slip ring. The interior of the slip ring uses silicon carbide sealing rings and wear-resistant bearings to ensure long-term sealing performance under high-speed rotation (usually 5-20 RPM) and extreme temperature differences (-40°C to 80°C)

Technical challenges and solutions

Wind turbines are often located at sea or in high-altitude areas and face problems such as salt spray corrosion, vibration and impact. Therefore, the shell of gas-liquid slip rings is mostly made of anodized aluminum alloy or stainless steel, and the internal seals are made of fluororubber or polytetrafluoroethylene (PTFE) to enhance weather resistance. In addition, some high-end designs introduce self-lubricating channels to reduce mechanical wear through internal circulating oil films. For example, Siemens Gamesa's 6MW offshore wind turbine adopts a dual-circuit slip ring system. The main circuit is responsible for the pitch hydraulic pressure, and the backup circuit is used for emergency braking, which significantly improves system reliability.

Economic benefits

According to industry statistics, the use of high-performance gas-liquid slip rings can extend the maintenance cycle of wind turbines to more than 2 years and reduce downtime losses caused by media leakage by up to 30%. In addition, the integrated slip ring reduces the complexity of the tower's internal pipelines, saving installation space and weight, which is especially important for large offshore wind turbines.