CavFlo Cavitation Control Valve Trim by MASCOT


Whenever the pressure of flowing liquid through a restricted area of a control valve drops below the vapor pressure of the liquid, and recovers to a pressure above the vapor pressure, cavitation damage to the control valve and connecting piping may occur. 

In the first stage of cavitation, vapor bubbles form downstream of the restricted area at the vena contracta (point of narrowest fluid constraint). The enlarging passage at downstream of the vena contracta reduces the velocity and thereby associated pressure recovery causes the vapor bubbles collapse or implode suddenly.

This implosion of the bubbles on metal surfaces causes stresses, eventually resulting in tearing away particles of the metal from the surface towards inward. Cavitation damages the plug and seat of a control valve as throttling occurs at the restriction, in the clearance between the plug and seat ring. If the vapor bubbles implode near them, the valve body and piping can also be damaged.

MASCOT's CavFlo Trim utilizes many small holes for diametrical flow through the walls of the seat retainer. As the valve plug lifts, increasing pairs of holes are opened. Each hole discharges a jet of cavitating liquid at the center of the retainer, which impinges with a jet of liquid admitted through the opposing hole. The impinging fluid jets form an area of pressure recovery and a fluid cushion. This phenomenon collapses the vapor bubbles in the fluid stream, away from metal parts preventing damages.

For more information about MASCOT Control Valves, contact Mountain States Engineering and Controls. Call them at (303) 232-4100 or visit their website at https://mnteng.com.