Dams and Hydro Power Plants

Functions of Valves in Dams

Flow Regulation: Controlling the release or diversion of water from reservoirs to downstream rivers, irrigation systems, or hydroelectric plants.
Water Level Management: Maintaining desired reservoir levels for flood control, water supply, and ecological balance.
Emergency Control: Quickly releasing water during emergencies to prevent overtopping or structural failure.
Maintenance and Inspection: Isolating sections of the dam or associated pipelines for safe inspection and repair work.

Applications of Valves in Dam Operations

Outlet Works: Valves manage the release of water from the reservoir to rivers, irrigation channels, or treatment plants.
Spillways: Emergency or auxiliary valves control water flow during flood events.
Hydropower Generation: Valves regulate water supply to turbines, optimizing electricity production and ensuring safety.
Intake Structures: Valves control the entry of water into pipelines or tunnels for distribution or power generation.

Key Considerations in Valve Selection

Water Pressure and Flow Rate: Valves must withstand and control varying pressures and flow volumes.
Operational Frequency: Some valves are designed for frequent operation, while others are reserved for emergencies.
Maintenance Access: Ease of inspection and repair is crucial for long-term reliability.
Environmental Impact: Valves should minimize downstream erosion, turbulence, and ecological disruption.

Common Types of Valves Used in Dams

Gate valves

Gate valves are among the most widely used in dam structures. They operate by raising or lowering a gate to start or stop water flow. These valves are suitable for on/off control and are typically used in penstocks and outlet works.

Butterfly Valves

Butterfly valves use a rotating disc to regulate water flow. They are favored for their compact design, ease of operation, and suitability for large-diameter pipes. Butterfly valves are often found in outlet conduits and diversion tunnels.

Ball and Spherical Valves

Ball valves employ a spherical closure unit to control flow. They are reliable, offer quick shut-off, and are used in high-pressure and high-flow conditions, often in smaller pipelines or as auxiliary valves.

Needle Valve (Axial Flow Control Valves/Plunger Valves)

Needle valves are designed for precise flow regulation. Their tapered design allows for accurate adjustments, making them ideal for bypass lines or situations requiring controlled water release.

Fixed Cone Valves (Hollow Jet Valves)

These specialized valves dissipate energy by converting pressurized water into a hollow jet, reducing downstream erosion. They are commonly installed at the downstream end of conduits for controlled releases.

Sleeve Valves

Vertical sleeve valves are commonly employed in dam turbine bypass systems to provide reliable and controlled water release when the main turbine is offline or during maintenance.

Check Valves/ Non return valves

Check valves prevent backflow, protecting dam structures and equipment from reverse flows that could cause damage or operational issues.

Air valves

Air valves are used to release trapped air or admit air into pipelines and conduits, preventing vacuum conditions and maintaining system integrity.