Valcor Engineering Corporation

Nuclear & Power Division Venturis & Orifices


When used in flow systems, cavitating venturis limit max flow of fluids regardless of downstream pressure. These are passive devices that operate in a non cavitating mode until their design (cavitating) point (inlet pressure and flow) is reached. Cavitation occurs when the absolute pressure of the fluid equals its vapor pressure. The cavitation (formation of bubbles) restricts any increase in flow.


Cavitating venturis can be used to limit flow as a result of a design basis accident (guillotine break) or as an alternative to an active control loop to control flow for a bypass or recirculation line. They have historically been used in the Chemical and Volume Control System and Auxiliary Feed Water systems. Lacking any moving parts, our venturis require no maintenance whatsoever.

Design Features and Benefits

  • Custom designed by our partner Fox Valve to meet specific operating requirements of the end user
  • Sizes up to 6” with customer specified end fittings – butt weld, flanged, NPT
  • Designed and manufactured to ASME Section III, Class 1, 2, 3 or customer specified code
  • Flow testing available to verify caviatation point
  • Simplifies/reduces process control components
  • Typical fluids include de-ionized water, Steam Generator feed water, borated water

Why Use Cavitating Venturis?

Most people are aware they can procure a pressure regulator to install in a line to regulate the pressure they need, but most are unaware of any passive device that can regulate flow. To generate fixed, stable flow rates in a process, an elaborate control loop is necessary consisting of a flow meter, PLC/computer and an active control valve. The PLC continually transmits changes to the control valve to regulate or maintain flow rates.

This can all be replaced with a Valcor cavitating venturi. By setting a fixed upstream pressure (about 15% higher than the maximum downstream pressure anticipated) with a pressure regulator, the cavitating venturi will deliver fixed, stable, repeatable flow rates that are entirely unaffected by changes or fluctuations downstream.