Throttle Pipe & Orifice Plate

Compute throttle-pipe and pressure-reducing orifice-plate hydraulic losses.

Throttle pipe hydraulic calculation

When the throttle velocity exceeds 20 m/s the value is over-limit (flagged orange).

Main-line flow Q (L/s)

Throttle calculated diameter Dg (mm)

Throttle length L (m)

Mean throttle velocity

—

m/s

Total loss ΔP

—

v = Q·0.001 / (0.785·(Dg·0.001)²); ΔP = 0.7·v²/19.62 + 0.00107·L·v²/(0.001·Dg)^1.3

Pipe diameters map to calc diameters: DN25→Dg26, DN32→Dg34.5, DN40→Dg40, DN50→Dg52, DN70→Dg67, DN80→Dg79.5, DN100→Dg105.

Pressure-reducing orifice plate

Orifice aperture d (mm)

Main calculated diameter Dj (mm)

Flow Q (L/s)

Pipe velocity

—

m/s

Orifice velocity

—

m/s

Resistance loss ΔP

—

ΔP = (1.75·(1.1−x)/(x·(1.175−x)) − 1)² · v²/19.62, x = (d−1)²/Dj²