Concentric
Bore centred on the pipe axis. The reference geometry for standard differential pressure flow measurement.
- Clean liquids
- Gases
- Steam
Hover: bore stays coaxial — full annular symmetry.
ENGINEERING / 01 FLOW MEASUREMENT
Precision Flow Starts With the Right Orifice.
Engineered orifice plates and orifice flanges designed for accurate differential-pressure flow measurement, consistent performance and reliable industrial operation.
- Beta range
- 0.10 – 0.75
- Pipe sizes
- 50 – 1000 mm
- Design basis
- ISO 5167 principles
LIVE SECTION VIEW — PRECISION ENGINEERING
FUNDAMENTALS / 02 DEFINITION
What Is an Orifice Plate?
An orifice plate is a precision-machined restriction installed inside a pipeline. The restriction creates a pressure difference as fluid flows through it. That differential pressure can be measured and used to determine flow rate.
SELECT A COMPONENT
Hover, tap or keyboard-focus any part of the section — pipe, plate, bore or pressure zones — to read what it does.
The principle is simple.
The engineering is not.
Differential pressure flow measurement has been understood for over a century. Repeating it accurately, in your pipe, on your fluid, for years — that is a manufacturing problem.
- GeometryBore diameter and roundness sit directly inside the flow equation. An error in d is squared in the result.
- Edge conditionThe upstream edge must be sharp and burr-free. A rounded edge shifts the discharge coefficient.
- MaterialChosen for the process fluid, temperature and pressure — and documented, so it can be traced.
- Surface finishRoughness on the upstream face changes the approach flow profile near the plate.
- ConcentricityThe bore must be centred to the pipe. Offset introduces a systematic error you cannot calibrate away.
- InstallationStraight lengths, tap position and orientation are part of the measurement — not an afterthought.
PRINCIPLE / 03 BERNOULLI + CONTINUITY
How an Orifice Plate Measures Flow
Fluid cannot slow down and speed up for free. Force it through a smaller area and it accelerates; the energy for that acceleration comes out of its static pressure. Measure that pressure drop and you have a flow signal.
PRESSURE & VELOCITY ALONG THE PIPE AXIS
EDUCATIONAL FORM
Q=
C·A·
√2 ΔPρ
Volumetric flow from discharge coefficient, bore area, differential pressure and density. Useful for understanding the physics — not for sizing a plate.
WORKING FORM — ISO 5167 STRUCTURE
qm=
C√(1 − β4)
·ε·
π4
d2·
√2 ΔP ρ1
Mass flow with the velocity-of-approach factor 1/√(1−β⁴), expansibility ε for compressible fluids, and a discharge coefficient C that itself depends on β, Reynolds number and tap arrangement.
As fluid passes through the restriction, its velocity changes and a measurable pressure differential is created. By measuring this differential pressure and applying the appropriate flow equation and discharge coefficient, flow rate can be calculated. Real engineering values depend on the applicable standard, fluid properties, geometry, Reynolds number, pressure tap arrangement, installation and upstream pipework.
TOOL / 04 PRELIMINARY SIZING
Calculate Your Orifice
Turn process conditions into an engineered orifice specification.
LIVE PLATE GEOMETRY SCALED TO PIPE ID
β = d / D0.600
ORIFICE BORE — d
60.00 mm
2.362 in
DIFFERENTIAL PRESSURE — ΔP
250.0 mbar
25.00 kPa
- Pipe diameter — D
- 100.0 mm
- Beta ratio — β
- 0.600
- Mass flow
- 13.86 kg/s
- Volumetric flow
- 50.0 m³/h
- Pipe velocity
- 1.77 m/s
- Bore velocity
- 4.91 m/s
- Reynolds number — ReD
- 1.76 × 10⁵
- Discharge coefficient — C
- 0.6045
- Expansibility — ε
- 1.0000
- Permanent pressure loss
- 142 mbar
- Plate thickness — E (guide)
- 3.0 – 5.0 mm
- Bore edge thickness — e (guide)
- 0.50 – 2.00 mm
ENGINEERING STATUS
For preliminary engineering estimation only. Final orifice sizing should be verified against the applicable standard and process conditions by a qualified engineer. The calculation follows the structure of ISO 5167-2 (concentric plates) using the Reader-Harris/Gallagher discharge-coefficient equation; it is not a statement of compliance or certification.
CONFIGURATION / 05 BORE GEOMETRY
Designed for Different Flow Applications
The bore geometry is chosen for what is actually moving through the pipe. Solids, condensate and suspended particles all change the right answer.
Eccentric
Bore offset toward the pipe wall so solids or condensate are not trapped against the plate face.
- Fluids containing solids
- Applications where drainage matters
- Wet gas & condensate lines
Hover: bore shifts off-axis toward the wall.
Segmental
A circular segment opening rather than a round bore — an open channel along the bottom of the pipe for heavy carry-over.
- Dirty fluids
- Slurries
- Suspended particles
Hover: opening becomes a chord segment.
Sizing correlations differ between geometries. The calculator above follows concentric-plate equations; eccentric and segmental plates are sized on their own basis.
PROCESS / 06 BUILD ROUTE
From Process Data to Precision Metal
Nine steps, in order, because the order matters. Each one is a place where a plate either keeps its accuracy or quietly loses it.
- 01
Engineering input
Pipe size, fluid, flow range, pressure, temperature, tap arrangement and installation constraints.
- 02
Design & calculation
Bore sized against the applicable standard for the stated conditions, with beta ratio and ΔP reviewed together.
- 03
Material selection
Material chosen for fluid compatibility, temperature and pressure, then recorded against the job.
- 04
CNC / precision machining
Outside diameter, thickness, tab and bore machined to the drawing.
- 05
Bore finishing
Upstream edge brought sharp and burr-free; downstream bevel formed where the design calls for it.
- 06
Dimensional inspection
Bore diameter, roundness, concentricity, flatness and thickness checked and recorded.
- 07
Surface & visual inspection
Face finish and edge condition examined — the two things a flow computer cannot correct for.
- 08
Documentation
Dimensional record, material information and calculation sheet issued with the plate.
- 09
Final dispatch
Identification marked on the tab, protected and packed for transport.
Bad geometry vs precision geometry
TOLERANCE / 07 ERROR PROPAGATION
Small Geometry. Big Consequences.
Bore area scales with d², so a bore error propagates into the flow result roughly twice over. Move the slider and watch a tolerance become an uncertainty.
Bore tolerance± 0.02 mm
Flow uncertainty from bore± 0.04 %
Measurement confidencePrecision
Bore held to a precision tolerance. The geometric contribution to uncertainty is small compared with the transmitter and installation.
- Bore diameter accuracy
- Bore roundness
- Edge sharpness
- Concentricity
- Plate flatness
- Surface finish
- Material consistency
- Correct installation
- Proper pressure tapping
Illustrative geometric propagation only — total measurement uncertainty also depends on the discharge coefficient, the transmitter, fluid property data and installation.
POSITION / 08 WHAT YOU ACTUALLY GET
Why Choose Orifice?
Not "best quality". Specific, checkable engineering practice.
Precision
Controlled bore geometry and dimensional inspection on every plate.
Engineering-first design
Sized from your process conditions rather than a one-size-fits-all bore table.
Material traceability
Material and manufacturing information documented and issued with the plate.
Consistency
Repeatable machining and inspection steps, so plate two matches plate one.
Documentation
Technical specification, dimensional record and inspection information supplied as standard.
Application support
Help selecting the plate configuration and tap arrangement that suits your process.
INDUSTRIES / 09 WHERE PLATES RUN
Where the Restriction Earns Its Place
Wherever a line needs a robust, serviceable flow measurement with no moving parts, a differential pressure element is still the working answer.
TYPICAL MEASUREMENT PATH
STEAM
PIPE
ORIFICE
DP TRANSMITTER
FLOW READING
- Oil & Gas
- Chemical Processing
- Petrochemical
- Power Plants
- Steam Systems
- Water Treatment
- Pharmaceutical
- Food Processing
- Compressed Air
- Industrial Gas
SYSTEM / 10 LOOP VIEW
The Plate Is Only One Part of the Measurement System
The plate creates the differential pressure. Everything downstream of it decides how faithfully that differential becomes a number on a screen.
- PIPE
Carries the process fluid, with straight lengths that set the approach profile.
- ORIFICE PLATE
Creates a repeatable, geometry-defined restriction.
- PRESSURE TAPS
Sense static pressure upstream and downstream at defined positions.
- IMPULSE LINES
Carry pressure to the transmitter — sloped, filled and free of trapped gas or condensate.
- DP TRANSMITTER
Converts the differential pressure into an electrical or digital signal.
- FLOW CALCULATION
Applies the flow equation with C, ε, β and fluid density.
- FLOW READING
The number the operator acts on.
RECORDS / 11 WHAT SHIPS WITH THE PLATE
Engineering Data, Not Marketing Claims
Every plate should arrive with paperwork that lets someone else check the work. The templates below are blank samples — contents are completed per job.
NEXT STEP / 12 ENGINEERING REQUEST
Give Us Your Process Conditions.
We'll Engineer the Restriction.
Pipe size. Fluid. Flow rate. Pressure. Temperature. That's where precision starts.
CONTACT / 13 ENGINEERING DESK
Need help sizing an orifice?
Talk to an engineer.
Send what you know. If something on the list is missing, say so — half the job is working out which numbers actually matter for your line.