WATER HAMMER CAUSES AND CURES.

Water hammer is the audible signal of a sudden change in pressure. It results from, and is most often associated with, rapid valve closing. Actually, water hammer is caused by, and is directly proportional to a change in the velocity of the fluid flowing in a closed conduit. The velocity change creates a shock wave with a pressure directly related to the velocity change. Rapid valve closing creates two conditions necessary for a pressure wave to form - velocity is abruptly changed and a dead-end condition is created. The article discusses these two conditions, methods for calculating the magnitude of the pressure wave, and methods for controlling or eliminating it.