Liquid Restriction Orifice Plate Calculator

Liquid ROP Sizing Calculator Guide (PDF)

This calculator determines the orifice diameter required to restrict the flow rate of liquid in a pipe using a sharp edge restriction orifice plate.

The calculation is based on the method described in Crane Technical Paper 410M.

The orifice flow coefficient is determined automatically.

1. Enter the required permanent pressure loss across the orifice
2. Enter the fluid density and viscosity
3. Enter the required flow rate through the orifice
4. Enter the internal diameter of the pipe in which the orifice will be installed
5. Click the "Calculate" button
6. The calculator will determine the orifice diameter required to give the required flow rate and pressure loss
7. The calculator will also determine:
   • Orifice velocity head loss coefficient
   • Beta ratio of the orifice (orifice diameter:pipe internal diameter)
   • Pipe Reynolds number
   • Orifice flow coefficient
   • Pressure difference across orifice (upstream pressure - vena contracta pressure)
   • Orifice flow area
8. The Beta ratio must be less than 0.8 for the orifice design to be acceptable
9. If the Beta ratio is calculated to be outside of this range a warning message will be displayed
10. If Beta ratio > 0.8:
    • Increase pressure loss across orifice
    • Increase the pipe internal diameter
    • Reduce the flow rate