Why is there a noise when I turn on the faucet?

Sometimes when you turn on the faucet, the faucet will make a "humming - humming" sound. Especially when the water supply is restored after the water is cut off, you will definitely hear a loud "humming" sound when you turn on the faucet. What is the reason for this?

The occasional "humming" sound when the faucet is turned on is actually a physical phenomenon known as "water hammer" or "water hammer." To put it simply, when the water is flowing rapidly in the water pipe, if the faucet is closed instantly, the water in the water pipe will bounce back and then bounce back. Most of the water pipes are made of metal materials, so they will be "knocked" by the water hammer, and then make the "humming" sound we hear.

Water hammer occurs not only in domestic water pipes, but also in pipes for central heating in the north. The "water hammer" in the heating pipeline is mainly that the high-temperature steam enters the pipeline and gradually cools down. When the generated condensed water flows to the bottom of the tube and accumulates in large quantities, because the wall of the heating pipeline is very smooth, the subsequent water flow is greatly affected by inertia. Hydraulic power to impact the pipeline, posing a serious threat to the safety of the pipeline. Therefore, it is necessary to warm the pipes before resuming the heating every winter, and drain the condensed water in the pipes in time to prevent the pipes from being damaged due to water hammer.

In addition to posing a safety threat to the pipeline, "water hammer" can also cause an oolong event in which the water meter is idling. If a neighbor's household water creates air, the air bubbles can cause "air hammer" or "water hammer", creating a localized pressure differential in the water pipe. If this pressure difference happens to run to other water meters, it will affect the water flow and cause the water meters to idle.

But you don't have to worry too much. Generally, the phenomenon of "air hammer" and "water hammer" in the pipeline network is common in small high-rise buildings and old communities with secondary water supply. This problem generally does not occur with new smart water meters that are now equipped with "check valves".

Don't look at "water hammer", it seems that it can only bring trouble to our lives, but if you change the angle, "water hammer" can play its proper role.

For example, the explosive lethality of weapon mines in water is a perfect application of the water hammer effect. When a mine explodes in water, a large amount of gas will be produced, which will rapidly diffuse into bubbles due to pressure changes, release the energy generated by the explosion, and the shock waves and bubbles generated will form the first blow to the hull. But at the same time, because the water has a certain pressure, after the bubbles generated by the explosion disappear, the squeezed water is quickly backfilled, and the energy of the backpressured water body is greater than the energy generated by the explosion, and the formed "water hammer" will cause more serious damage to the hull. The blow, the destructive power is even more powerful than the first time.

Now do you understand what the water hammer phenomenon is all about?