What exactly does "water hammer effect" refer to, and is it harmful to water meters?
Water hammer is also called water hammer. It refers to the phenomenon that the flow rate changes suddenly and the pressure fluctuates greatly due to the sudden opening and closing of the valve and the sudden start and stop of the water pump during the transportation of water or other liquids. To put it more simply: a sudden power failure or a valve closes too fast, due to the inertia of the pressure water flow, a shock wave of the water flow is generated, just like a hammer, we call it water hammer.
How scary is the water hammer effect:
The wall of the water supply pipeline is smooth, and the subsequent water flow will quickly reach the maximum under the inertia of the "accomplice", so it is easy to cause damage (such as damage to valves and pumps, etc.), which is the "water hammer effect" in hydraulics, also called positive water. On the contrary, the sudden opening of the valve or water pump will also produce a water hammer effect, which is called negative water hammer. Such a large fluctuation of pressure shock wave can easily lead to the rupture of the pipeline due to local overpressure and damage to the equipment. Therefore, the protection of water hammer effect is a key factor that must be considered in the design and construction of water supply pipeline engineering.
Conditions for water hammer
1. The valve opens or closes suddenly;
2. The pump unit suddenly stops or starts;
3. A single pipe delivers water to a high place (the height difference of the water supply terrain exceeds 20 meters);
4. The total head (or working pressure) of the pump is large;
5. The water velocity in the water pipeline is too large;
6. The water pipeline is too long and the terrain changes greatly.
7. Irregular construction is a hidden danger in water supply pipeline engineering
7.1 The production of cement thrust piers for joints such as tees, elbows and reducers does not meet the requirements.
Hazards of water hammer effect:
The pressure increase caused by water hammer can reach several times, or even dozens of times, the normal working pressure of the pipeline. Such large pressure fluctuations mainly cause harm to the pipeline system:
1. Cause the pipeline to vibrate strongly, and the pipeline joint is disconnected;
2. Destroy the valve, the serious pressure is too high, causing the pipeline to burst, and the pressure of the water supply network is reduced;
3. On the contrary, if the pressure is too low, it will lead to the collapse of the pipe, and also damage the valve and fixing parts;
4. Cause the pump to reverse, damage the equipment or pipelines in the pump room, cause serious flooding of the pump room, cause personal injury and other major accidents, and affect production and life.