Water Distribution Networks

Functions and Importance

Flow Control: Valves allow operators to start, stop, or adjust water flow as needed for maintenance, emergencies, or operational efficiency.
Isolation: By isolating sections of the network, valves enable repairs and upgrades without disrupting the entire system.
Pressure Management: Certain valves help maintain safe and consistent water pressure across the distribution system.
Backflow Prevention: Check valves and backflow preventers are crucial for protecting potable water supplies from contamination.
Air Management: Air release and vacuum valves prevent air pockets and negative pressure, which can disrupt flow and damage infrastructure.

Applications in Water Distribution

Valves are strategically placed throughout water distribution networks. Some common applications include:

At pump stations to control supply and protect equipment
At critical junctions and intersections for system flexibility
Along main and branch lines for routine maintenance and emergency isolation
At customer service connections to manage supply and prevent unauthorized usage
Near reservoirs and tanks for level and pressure control

Types of Valves Used in Water Distribution Networks

Several types of valves are commonly found in water distribution systems, each serving specific functions and suited to different applications. The main types include:

Needle Valve (Axial Flow Control Valves/Plunger Valves)

Needle valves are specialized flow control valves designed to provide precise regulation of water flow and pressure. They operate by moving a cylindrical plunger in and out of the flow path, allowing for fine adjustments and minimizing turbulence. Needle valves are often used in applications requiring accurate flow control, such as at pump stations, reservoirs, or pressure reducing installations and water distribution control.

Gate valves

Used primarily for on/off control. They feature a sliding gate that opens or closes the flow path. Gate valves are commonly installed in main supply lines and are valued for their minimal pressure drop when fully open.

Butterfly Valves

These valves use a rotating disc to control flow. Butterfly valves are lightweight, compact, and ideal for large-diameter pipelines where quick shut-off is necessary.

Ball and Spherical Valves

Ball valves use a spherical closure unit to start or stop the flow. They offer tight sealing and are often used for shut-off applications in distribution networks.

Check Valves/ Non return valves

These are one-way valves that prevent backflow, ensuring water flows in only one direction. They are essential in protecting the system from contamination and pressure surges.

Air valves

Installed at high points in the system to release trapped air, which can reduce efficiency and cause water hammer.