Page 50 - Valve Selection Handbook
P. 50
Fundamentals 37
Figure 2-10. Relafionship Between Flow Rate, Valve Opening Position, and Pressure
Loss in a Pumping System.
Cavitation of Valves
When a liquid passes through a partially closed valve, the static pres-
sure in the region of increasing velocity and in the wake of the closure
member drops and may reach the vapor pressure of the liquid. The liquid
in the low-pressure region then begins to vaporize and form vapor-filled
cavities, which grow around minute gas bubbles and impurities carried
by the liquid. When the liquid again reaches a region of high static pres-
sure, the vapor bubbles collapse suddenly or implode. This process is
called cavitation.
