YDK WATER HAMMER ARRESTER VALVE | MODEL: KWH-10K

Hydraulic shock (water hammer) occurs when a valve closes suddenly or a pump stops unexpectedly, creating a pressure wave that surges many times above normal and propagates through the pipeline. This can easily crack or burst pipes, damage valves and flanges, and shake the entire system. The YDK water hammer arrester valve, Model KWH-10K, is a technical solution that absorbs the shock pressure and protects water supply and industrial piping systems.

General information on the YDK KWH-10K water hammer arrester valve

A water hammer arrester valve (also called an anti-surge valve) is a device installed on a pipeline to absorb and dissipate sudden pressure waves (water hammer). It is a valve type that uses an air cushion combined with a disc mechanism to absorb shock. The YDK KWH-10K water hammer arrester valve consists of 4 main parts:

Construction table of the YDK KWH-10K water hammer arrester valve

Dimension table of the YDK water hammer arrester valve, Model KWH-10K

(*) The specifications of products in this catalogue may be changed without prior notice.

Operating principle of the YDK water hammer arrester valve (KWH-10K)

In operation, the YDK water hammer arrester valve goes through 4 states:

1. Normal state (no pressure surge)

When the system is operating steadily, the water pressure in the pipeline remains at its normal level. The disc inside the valve is in a closed/balanced state, and the air cushion chamber above holds a pre-charged amount of compressed air, filled through the 1/8″ nozzle during installation. This air volume acts as an “air spring”, always ready to absorb shock.

2. When water hammer occurs

When the flow velocity changes suddenly, for example:

• A pump stops suddenly due to a power failure or shutdown
• A valve closes quickly
• The flow direction reverses suddenly

The kinetic energy of the moving water column is destroyed instantly, generating a pressure surge wave that propagates back through the pipeline at very high speed (up to hundreds of m/s), producing a peak pressure many times higher than the normal working pressure.

3. Shock absorption process

This pressure surge wave reaches the water hammer arrester valve and pushes the internal disc open, and water rushes into the air cushion chamber above. The air in the chamber is compressed instantly and absorbs most of the shock energy, instead of letting that energy rebound into the pipe wall, flanges, or other equipment in the system.

At the same time, the internal rubber cushion continues to mechanically damp the remaining residual energy, so that the pressure reduction process is smooth and repeated resonant oscillation is avoided.

4. Recovery state

After the pressure surge has passed, the compressed air in the chamber expands again and pushes the water out, and the disc closes back to its original position. The system returns to normal pressure, and the valve is ready for the next shock-absorbing cycle.

Note: The damping effectiveness of the water hammer arrester valve depends directly on the amount of compressed air remaining in the cushion chamber. Over time, the air tends to dissolve gradually into the water (especially at high pressure), so the air must be checked and topped up periodically through the 1/8″ air nozzle. Otherwise the valve will gradually lose its effect and act only as an ordinary water-holding chamber.

Installation locations and orientation of the water hammer arrester valve

Recommended installation locations

The water hammer arrester valve should be installed as close to the source of the pressure surge as possible, in order to absorb the energy right at the point where it is generated, before the pressure wave travels far and harms the entire system.

• After the pump outlet: This is the most common location, especially for water supply pump stations, fire protection pumps, and booster pumps, where sudden pressure drops or surges often occur when the pump is stopped or started.
• Before/after quick-closing/opening valves: Place it immediately upstream of devices such as solenoid valves, automatically controlled ball valves, spring check valves, and so on, which are valve types with very short closing times that readily generate large pressure surges.
• At the end of long pipelines or at sudden changes of direction (90° elbows, tees): At these points of flow direction change, where the fluid velocity is high, the pipe is directly exposed to the shock wave.
• Before pressure-sensitive equipment (high-precision flow meters, pressure reducing valves, measuring instruments), to protect it from damage caused by repeated pressure surges.

Notes on the orientation and installation method of the YDK water hammer arrester valve

• Orientation: The water hammer arrester valve is normally installed vertically, with the air cushion chamber facing upward, so that the compressed air is not carried out of the chamber by the water under gravity.
• Connection: For Model KWH-10K, the valve connects through a JIS 10K flange, directly on the main pipeline or through a branch near the point where the pressure surge originates.
• Do not install after a shut-off/isolation valve: If the shut-off valve closes, the water hammer arrester valve will be isolated from the main pipeline and will lose its protective effect at the very moment it is needed most.

If you need further consultation or a detailed quotation for the YDK water hammer arrester valve, Model KWH-10K, please contact An Phu Thanh directly via Hotline/Zalo: 0946 729 913. Our team is always pleased to serve you.