Working Principle of Hydraulic Elevator Dam (HED)

1. Core Function Overview

2. Hydraulic Drive Mechanism

• Energy Conversion: The hydraulic pump station (driven by an electric motor) draws hydraulic oil from the reservoir and pressurizes it (typically 10–20 MPa, depending on design). This converts electrical energy into hydraulic energy (pressurized oil).
• Force Transmission: Pressurized oil is delivered via steel pipes/hoses to hydraulic cylinders mounted symmetrically behind the water-retaining panel. When oil enters the cylinder’s rod chamber, it pushes the piston rod outward, lifting the panel upward. Conversely, when oil is directed to the rodless chamber, the piston rod retracts, lowering the panel.
• Speed and Precision Control: Flow control valves in the hydraulic circuit regulate oil flow rate, adjusting the panel’s lifting/lowering speed (usually 0.1–0.5 m/min). Check valves prevent backflow, ensuring the panel remains stable at any position.

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3. Structural Support and Stability

• Guide Rails: Vertical rails guide the panel’s movement, preventing lateral deviation. Their high straightness (≤1mm/m tolerance) ensures friction-free motion, even under high water pressure.
• Water-Retaining Panel: The panel (steel or reinforced concrete) is designed to resist hydrostatic pressure. Its edge seals (rubber or composite materials) prevent water leakage between the panel and foundation/rails when closed or partially raised.
• Foundation and Supports: The concrete foundation and steel brackets distribute the panel’s weight and water pressure to the ground, avoiding settlement or tilting during operation.

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4. Control System Coordination

• Sensing and Feedback: Water level sensors (ultrasonic or pressure-based) monitor upstream/downstream levels (accuracy ±10mm). Position sensors (linear encoders) track the panel’s height, while pressure sensors monitor hydraulic system pressure.
• Decision-Making: A PLC (Programmable Logic Controller) processes sensor data. In automatic mode, it compares real-time water levels with preset thresholds (e.g., "high" = 5.0m, "low" = 3.0m) and triggers hydraulic adjustments:

• If water exceeds the "high" threshold, the PLC signals the hydraulic system to lower the panel, releasing water.

• If below the "low" threshold, it commands the panel to rise, retaining more water.

• Manual Override: Operators can switch to manual mode via a control panel, using buttons to directly raise/lower the panel (e.g., for maintenance or unexpected conditions). Emergency stop buttons cut hydraulic power instantly if faults (e.g., jamming, leaks) occur.

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5. Dynamic Balance During Operation

• Hydraulic pressure in the cylinders (maintaining the panel’s height).

• Structural rigidity of the guide rails and foundation (resisting lateral thrust).

• Symmetrical cylinder arrangement (ensuring uniform force distribution to prevent panel deformation).

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