Name: What is Water Hammer? | DFT Inc.
Uploaded: 2025-03-08T08:51:43.000Z
Duration: 2 min 39 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Water hammer is a shock wave, transmitted through fluid contained in a piping system.

It occurs when fluid in motion is suddenly forced to stop moving, and frequently occurs at pump shutdown.

We'll be showing the difference between using a swing check valve.

And a spring assisted DFT silent check valve.

Here you can see the fluid flow upon pump startup.

The motion and slamming of the swing check can cause damage to sealing surfaces and fatigue.

When the pump shuts down, it is gravity and reverse flow that closes or slams the swing check valve closed, resulting in pressure wave build and water hammer.

Water hammer can also damage pipe hangers, instrumentation, and lead to dangerous work environments.

Now you see an Excalibur model DFT spring assisted silent check valve on pump startup.

When the pump shuts down, the spring assisted silent check valve closes the head of reverse flow before fluid momentum changes direction, thereby significantly reducing water hammer.

Pressure spikes are minimal because the disc closes ahead of the reverse flow.

Now you see a side by side comparison of DFT silent check valve and a swing check.

University and independent laboratory studies have shown that the dynamic characteristic of the axial flow, spring assisted silent check valve, DFT check valves favors fast closing ahead of reverse flow.

Therefore, reducing pressure spikes and water hammer.

Specify DFT check valves to replace your unreliable, high maintenance swing check or double door check valve.

Significantly reduce water hammer problems.

Visit us online at DFT-valves.com to view our complete selection of inline nozzle style non slam check valves.