Liquid flowing through any orifice will cavitate whenever its velocity causes the pressure in the throat of the orifice to drop below the vapor pressure of the flowing liquid. Even though there may be a high supply pressure and a high back pressure on the orifice, if the velocity is high enough there will be a subsequent lowering of the pressure in the throat of the orifice and the possibility of cavitation.
The effects of cavitation are choked flow and erosion - both of which are undesirable. To prevent cavitation, the throat pressure must be maintained, either by:
The use of Lee Multi-Orifice Restrictors (Bender Jet, Axial Visco Jet, JEVA and Visco Jet) can significantly reduce the possibility of cavitation. Their unique design allows the total pressure drop to be divided across each individual orifice, reducing throat velocity and increasing back pressure relative to the pressure drop across each individual orifice.
It is recommended that Lee Multi-Orifice Restrictors be considered whenever high pressure drops and low back pressures are required.