A knocking noise in a water pipe that occurs when a tap is turned off briskly.
（突然关水龙头水管发出的）水锤声，水击声
a paddle fitted to the arm of the ball valve will also prevent water hammer
Example sentencesExamples
If eliminating water hammer from an older house, locating the offending valve or faucet and installing a water arrester at that location is one solution.
Since installation I have had water hammer when the pump shuts off.
The sprinkler's closed-case design protects internal parts from debris contamination, while a steady piston valve guards against water hammer, pressure spikes and damage to the overall system.
Definition of water hammer in US English:
water hammer
nounˈwôdər ˌhamər
A knocking noise in a water pipe that occurs when a tap is turned off briskly.
（突然关水龙头水管发出的）水锤声，水击声
a paddle fitted to the arm of the ball valve will also prevent water hammer
Example sentencesExamples
The sprinkler's closed-case design protects internal parts from debris contamination, while a steady piston valve guards against water hammer, pressure spikes and damage to the overall system.
If eliminating water hammer from an older house, locating the offending valve or faucet and installing a water arrester at that location is one solution.
Since installation I have had water hammer when the pump shuts off.