Question
What is device of cavitations in pipes and drains?

Answer
Cavitations refer to arrangement of air foam in fluid in low-pressure condition that is lower than saturation pressure. It is potentially damaging situation in which fluid in pipes or sewers is at high velocities. Bernoulli's Equation, at high flow velocities, pressure head of fluid is concentrated as a result. As fluid pressure is less than saturation pressure, dissolved gases are released from fluid and these air bubbles will rapidly collapse when flow enters into region of higher force. This produces a high active pressure that causes break to the pipelines due to its high incidence.