Water Hammer in the Boiler System, Harm, and Preventive Measures

September 17, 2020

Water hammer 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 or the sudden start and stop of the water pump during the transportation of water or other liquids. It's like a lot of people lining up to run, and the person in front suddenly stops, and the person behind will bump into the person in front.

Several situations of water hammer.

1. Positive water hammer.

The sudden closing of the valve or sudden stop of the water pump will cause subsequent water flow to hit the valve or water pump.

2. Negative water hammer

The sudden opening of a valve or a water pump can also cause water hammer.

3. Pump stop water hammer

When a sudden power failure or other reasons cause the water pump to stop suddenly, the water pump and the pressure pipeline cause the pressure rise and fall due to the sudden change of the flow rate.

Conditions for water hammer in industrial boiler systems

1. The valve suddenly opens or closes;

2. The water pump stops or starts suddenly;

3. A single pipe delivers water to high places (the height difference of the water supply terrain exceeds 20 meters);

4. The total pump head (or working pressure) is large;

5. The water velocity in the water pipeline is too high;

6. The water pipeline is too long and the terrain changes greatly.

7. Irregular construction is a hidden danger in water supply pipeline engineering

8. The production of cement thrust piers such as tees, elbows, reducers, and other nodes does not meet the requirements.

Water hammer phenomenon in the steam system:

The harm of water hammer effect

1. Cause the pipeline to vibrate strongly and disconnect the pipeline joint;

2. Destroy the valve, severely high pressure causes 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 cause the collapse of the pipe and damage the valve and fixings;

4. Cause the water pump to reverse, damage the equipment or pipelines in the pump room, seriously cause the pump room to be submerged, cause personal injury and other major accidents, affect production and life.


1. Increase the pipe diameter.

2. Reduce the length of the water pipeline.

3. Choose a reasonable pump head according to local actual conditions. To

4. After stopping the pump in an accident, start the pump after the pipeline is full of water after the check valve. To

5. Do not open the pump outlet valve fully when starting the pump, otherwise, it will cause a big water shock.

Install a water hammer prevention device.

(1) Adopt PLC automatic control system

The frequency conversion speed control of the pump is carried out, and the operation of the entire water supply system is automatically controlled. Through the detection of the pressure of the pipe network, the feedback control of the opening, stopping and speed adjustment of the water pump, controlling the flow rate, and maintaining the pressure at a certain level, can be controlled by The microcomputer sets the water supply pressure of the pump and maintains the constant pressure water supply to avoid excessive pressure fluctuations and reduce the probability of water hammer.

(2) Install water hammer eliminator

This equipment mainly prevents water hammer when the pump is stopped and is generally installed near the outlet pipe of the water pump to balance the pressure of the local pipe and prevent the impact of water hammer on the equipment and pipes.

(3) Install a slow-closing check valve on the outlet pipe of the large-caliber water pump

It can effectively eliminate the water hammer when the pump is stopped, but because a certain amount of water flows back when the valve is operating, the suction well must have an overflow pipe. Disadvantages: When there is a hump in the pipeline to bridge the water hammer, the effect of the slow closing check valve is very limited.

(4) Set up the multi-stage check valve

In the long water pipeline, one or more check valves are added to divide the water pipeline into several sections. The disadvantages are: increased power consumption of the water pump during normal operation and increased water supply costs.

Preventing the water hammer effects can effectively protect the boiler system. Make the boiler system operation more stable. If you can tell us while using the boiler system, EPCB Boiler can help you answer.

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