Description and Working of Water Hammer Arrester

In plumbing systems, sudden changes in water flow can cause a phenomenon known as water hammer. Water hammer occurs when water moving at high speed in pipes is suddenly stopped by closing a valve or tap. This sudden stoppage creates a shock wave or pressure surge inside the pipe, which may produce loud banging sounds and damage plumbing equipment.

To prevent such pressure surges, a device called a water hammer arrester is used. A water hammer arrester absorbs the shock created by sudden pressure changes and protects the plumbing system from damage. It is an important component used in modern plumbing installations, especially where quick-closing valves or appliances are present.

What is a Water Hammer Arrester?

A water hammer arrester is a mechanical device installed in plumbing systems to reduce or eliminate the effects of water hammer. It works by absorbing the pressure shock produced when water flow suddenly stops. The device contains a chamber with air or gas that acts as a cushion to absorb the sudden pressure surge.

When the shock wave reaches the arrester, the compressed air or gas inside the chamber absorbs the energy and reduces the pressure in the pipe. This prevents the shock wave from damaging the pipes or fittings.

Need for Water Hammer Arresters

Water hammer can cause serious problems in plumbing systems if it is not controlled. Repeated pressure shocks may weaken pipes, loosen joints, and damage valves or appliances.

Water hammer arresters are therefore installed in pipelines to protect the plumbing system and ensure smooth water flow.

Reasons for Installing Water Hammer Arresters

• To reduce loud banging noises in pipes
• To prevent pipe damage caused by pressure surges
• To protect plumbing fixtures and appliances
• To maintain stable water pressure in pipelines

Construction of a Water Hammer Arrester

A water hammer arrester is usually made of metal such as brass or stainless steel. The device consists of a cylindrical chamber containing air or gas separated from the water by a piston or diaphragm.

The main parts of a water hammer arrester include:

• Outer body: The outer casing that holds the internal components.
• Piston or diaphragm: A movable component that separates the air chamber from the water.
• Air or gas chamber: A space filled with compressed air or gas to absorb pressure surges.
• Pipe connection: The inlet through which the arrester connects to the pipeline.

These components work together to absorb the energy produced by sudden changes in water pressure.

Working Principle of a Water Hammer Arrester

The working of a water hammer arrester is based on the principle of compressibility of air. Unlike water, which is almost incompressible, air can be compressed easily.

When water flowing in a pipe suddenly stops, a pressure surge travels through the pipeline. This surge enters the water hammer arrester and pushes the piston or diaphragm inside the chamber. As the piston moves, it compresses the air or gas inside the chamber.

The compressed air absorbs the energy of the pressure surge and reduces the intensity of the shock wave. After the pressure stabilizes, the piston returns to its original position, and the system continues to operate normally.

Location of Water Hammer Arresters

Water hammer arresters are usually installed near appliances or valves that cause sudden changes in water flow. Proper placement ensures that the pressure surge is absorbed quickly before it spreads throughout the pipeline.

Common installation locations include:

• Near washing machines
• Near dishwashers
• Near quick-closing valves
• Near pumps in water supply systems

Installing the arrester close to the source of the pressure surge improves its effectiveness.

Advantages of Water Hammer Arresters

• Reduces noise caused by water hammer
• Protects pipes and fittings from damage
• Improves the durability of plumbing systems
• Prevents leaks and pipe bursts
• Maintains smooth and stable water flow

Maintenance of Water Hammer Arresters

Water hammer arresters require minimal maintenance, but regular inspection is recommended to ensure proper functioning. Over time, components such as pistons or diaphragms may wear out or become damaged.

Plumbers should check for signs of leakage, unusual noise, or reduced performance. If the arrester is not working properly, it should be repaired or replaced.

Importance for Plumbers

For plumbers and technicians, understanding the function of water hammer arresters is essential for maintaining safe plumbing systems. Installing these devices helps prevent pressure surges that could otherwise cause serious damage to pipes and appliances.

Proper knowledge of water hammer prevention also helps plumbers design efficient water supply systems with minimal noise and reduced maintenance problems.

Conclusion

A water hammer arrester is an important device used to protect plumbing systems from pressure surges caused by sudden changes in water flow. It works by using a chamber filled with air or gas that absorbs the shock wave created by water hammer.

By reducing pressure surges and preventing pipe damage, water hammer arresters improve the safety and reliability of plumbing systems. For ITI plumber trainees, understanding the description and working of water hammer arresters is an important part of learning modern plumbing techniques.