How Do Water Hammer Arrestors Work?

A water hammer arrestor.

Water hammer arrestors are devices that control the loud knocking sounds in the pipes, which occur due to the sudden shut off of the water flow. It is caused by pressure waves. Through the pipes, this sound is caused by a sudden stop in the speed of water or change in direction. This happens when a washer stops filling up, for example, or when the dishwasher changes the cycle, or when the faucet is turned off suddenly.

How Water Hammer Arrestors Work

Water hammer arrestors consist of a spring and a waterproof air bladder. This will absorb the force of moving water. Water hammer arrestors are available in both commercial and residential capacities. They are effective even when the system of a pump and shutoff valve is in the same line. Water hammer arrestors are preferred over air chambers as arrestors do not require recharging as is in the case of air chambers.

Any fluid running in pipes that is not water can cause hammering noises and damage to the pipe system. Water hammer arrestors are also used in the chemical industry to prevent expensive instruments from being damaged.