Orifice Plate Sizing — online
Orifice bore for a flow and transmitter range, the flow from a measured differential, or the differential for a flow, by ISO 5167-2 — with β, C, ε, permanent loss, limit checks and straight lengths.
Yellow cells are inputs; orange cells are choices; blue cells choose the unit. Select or hover over an input to see its help in the box below the toolbar. The sheet is the same as the Excel tool (USD 29) — the Guide, method and references are in the Excel file.
What this orifice plate sizing calculator does
Size the bore of an orifice plate, or check a flow reading, using ISO 5167-2. Orifice bore for a flow and transmitter range, the flow from a measured differential, or the differential for a flow, by ISO 5167-2 — with β, C, ε, permanent loss, limit checks and straight lengths.
- Three ways to use it. Size the bore for a full-scale flow and differential range, find the flow from a measured differential, or the differential a new flow gives through an existing plate.
- Flange, corner and D–D/2 taps. Reader-Harris/Gallagher discharge coefficient and the expansibility factor, with their uncertainties.
- Liquids, gases and steam. Built-in fluid library, or your own density and viscosity; standard volume flow for gases.
- Real conditions. Thermal expansion of the plate and the pipe at the flowing temperature; permanent pressure loss.
- Limit checks. β, bore, pipe size, Reynolds number and pressure ratio, with plain-language findings and the straight lengths for the nearest fitting.
- Flow table and report. Flow against differential from 120 % to 10 % of full scale, with a chart and a one-page report for the instrument datasheet.
What you enter
- Calculate
- Pressure taps
- Fluid
- Phase
- Properties
- Flowing temperature
- Upstream pressure (at the upstream tap)
- Solution strength (glycol, brine …)
- Watson characterisation factor K
- Kinematic viscosity at 40 °C (oil)
- Kinematic viscosity at 100 °C (oil)
- Density (your value)
- Viscosity (your value)
- Molar mass (gas, your value)
What you get
- Diameter ratio β = d/D
- Pipe inside diameter at 20 °C
- Discharge coefficient C
- Expansibility factor ε
- Velocity of approach factor E = 1/√(1−β⁴)
- Mass flow
- Actual volume flow at the upstream conditions
- Standard volume flow (0 °C, 1.01325 bar)
- Differential pressure
- Pipe Reynolds number ReD
- Permanent pressure loss
- Density at the upstream tap
- Viscosity
- Straight length upstream (no straightening vanes)
How it was checked
25 of 25 checks within tolerance against a separate implementation of ISO 5167-2 and Perry's Chemical Engineers' Handbook, for water, air, steam and a viscous oil.
Related
- Free quick calculator — a simpler free version for a fast estimate.
- Calculation guide — the equations behind this tool, with a worked example.
- Orifice Plate Sizing Excel tool — USD 29, keep the workbook and its Guide.
- All 40 online tools
Questions
Is the orifice plate sizing calculator free?
You can enter and check all your data free. The full results, findings and printable sheet are unlocked with a 3-run pack (USD 9), a monthly subscription to all 40 online tools (USD 15) or a yearly one (USD 99).
Are the results the same as the Excel tool?
Yes. The online tool runs the formulas of the Orifice Plate Sizing Excel workbook, checked cell by cell against the Excel file.
Which units can I use?
SI, US customary and British units — choose the unit next to each input.