Hydraulic Cylinder Leak Detection in Wind Turbine Pitch Drives
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Solution Overview
Problem
Existing wind turbine hydraulic pitch drive systems face challenges in detecting internal oil leakage, which can lead to increased operational errors, costly maintenance, and premature component failure, especially in harsh offshore environments where maintenance is restricted and expensive.
Innovation Solution
A method and system for detecting oil leakage between the sections of a hydraulic cylinder using a movable piston with a sensor and remote-controlled valve, where the piston's position change is monitored to detect pressure differences, allowing for early detection of internal leaks and enabling remote, automatic self-diagnostic procedures without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic oil is used in a closed hydraulic system, then the system can operate reliably, but internal leakage cannot be detected easily
Solution Approach 1:
A sensor is introduced as an intermediary element that indirectly detects internal leakage by measuring piston position changes. The sensor does not directly detect oil leakage but measures the positional consequence of pressure equalization caused by leakage, enabling indirect detection of the hidden defect.
Solution Approach 2:
The system implements feedback by continuously monitoring piston position and comparing it against expected positions. When deviation exceeds a threshold, the system generates an alarm signal, creating a closed-loop detection mechanism that provides real-time feedback on system health status.
2Reliability
If hydraulic cylinders are serviced frequently to prevent failure, then reliability is maintained, but maintenance costs and operational stops increase
Solution Approach 1:
The detection system performs preliminary monitoring of piston position to identify early signs of internal leakage before actual failure occurs. By detecting degradation trends in advance, the system enables planned maintenance scheduling rather than reactive repairs, reducing unexpected operational stops.
Solution Approach 2:
The hydraulic system performs self-diagnosis through the integrated sensor that automatically monitors its own operational parameters. The system detects its own degradation without external inspection, enabling condition-based maintenance that replaces fixed-schedule servicing.
3Difficulty of detecting and measuring
If a sensor is added to detect piston position, then internal leakage can be detected, but device complexity increases
Solution Approach 1:
The sensor serves multiple functions: it monitors piston position for leakage detection, tracks cylinder performance trends, and provides diagnostic data for predictive maintenance. This multi-functionality justifies the added complexity by delivering comprehensive system monitoring beyond simple leakage detection.
Solution Approach 2:
The invention replaces complex mechanical leakage detection methods (such as pressure gauge arrays or flow meters) with a simple positional sensor. By substituting mechanical measurement systems with an electronic position sensor, the overall system complexity is reduced while maintaining detection capability.
4Reliability
If maintenance is performed in harsh offshore environments, then equipment reliability is maintained, but service time and costs are restricted and increased
Solution Approach 1:
The detection system enables the hydraulic cylinder to monitor its own condition and signal when service is needed, eliminating the need for frequent routine inspections in harsh offshore environments. The system performs self-assessment, reducing the burden on remote maintenance operations.
Solution Approach 2:
The sensor detects early signs of degradation before failure occurs, allowing maintenance to be scheduled during planned downtime rather than during urgent repairs. This preliminary detection capability transforms reactive offshore maintenance into proactive planning, reducing service complexity and cost.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables early detection of internal cylinder defects, reduces unnecessary maintenance, avoids operational stops, and provides cost savings by predicting and optimizing maintenance intervals, thereby prolonging the hydraulic cylinder's lifetime and ensuring constant functionality.
Implementation Method 1
The change of the position results from the difference of forces, which is in return resulting from the closed valve and from the alignment of the first pressure to the second pressure due to the leakage
Data Source
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AI summary
The invention refers to an arrangement and to a method to detect an oil leakage (LKG) between a first section (S1) of a hydraulic cylinder (HC) and a second section (S2) of the hydraulic cylinder (HC). A movable piston (MP) is arranged between the first section (S1) and the second section (S2) in a way that the piston (MP) changes its position (POS) between the sections (S1, S2). The change of the position is done in dependency of a difference between a first force (F1), which acts at the first section (S1) on a first cross sectional area (A1) of the movable piston (MP), and a second force (F2), which acts at the second section (S2) on a second cross sectional area (A2) of the movable piston (MP). The first section (S1) comprises hydraulic oil (HO) with a predefined first pressure (P1), while the first force (F1) is calculated based on this pressure (P1) and based on the first area (A1). The second section (S2) comprises hydraulic oil (HO) with a predefined second pressure (P2), while the second force (F2) is calculated based on this pressure (P2) and based on the second area (A2). The first section (S1) is connected with a remote controlled first valve (V1), which is closed for the leakage detection. A sensor (SEN) is coupled with the movable piston (MP) in a way that any change in its position (POS) is detected, while the change of the position results from the difference of forces (F1, F2) resulting from the closed valve (V1) and from the alignment of the first pressure (P1) to the second pressure (P2) due to the leakage (LKG). The sensor (SEN) is coupled with a control (CONT), which is prepared and arranged to detect the leakage of oil based on the change of the position (POS).