Cavitating Venturi

Cavitating Venturies for Liquid Flow Control

Fox Cavitating Venturies have been used since 1961 to maintain stable, accurate, repeatable flow rates in demanding applictions such as spacecraft, missiles, high energy lasers, and extremely corrosive chemical processes.

Cavitating venturies perform comparably with liquids to sonic chokes with gasses.

“Cavitation” to many engineers implies damaging erosion. However, loss of surface material seldom occurs in cavitating venturies because the total life exposure to actual cavitation may be small. There are many industrial and aerospace applications where a long installed life is required by actual operation while cavitating is relatively brief. These may include:

  • Rocket engine flow rate controls
  • Flow limiters or surge controls on pumps. The venturi operates normally in the non-cavitating mode but, during an emergency downstream, cavitates to limit flow.
  • Actuation control with multiple hydraulic cylinders. Cavitating venturies in each line create equalized movement in all cylinders, despite widely varying loads to each.
  • Flow dividers for deluge or spray type fire control systems. Flow is divided equally to all lines even if some nozzles downstream have burnt away. Commonly used in nuclear emergency feedwater systems.


Recovery refers to how high a backpressure a cavitating venturi can see and still maintain fixed, stable, repeatable flows. For Fox cavitating venturies, recovery is typically about 85%.