Orifice Plate - Find Flow Rate

ISO 5167-2:2003 Orifice Flow Calculator - Metric Units


Identification Data

Tagname
Site
Area
Notes

Fluid Data

Fluid
State of matter
Density
Kg/m3
Molecular Weight g
Operating Temperature
C
Operating Pressure (P1)
bar
Dynamic Viscosity
cP
Ratio of Sp.Heats N/A

Pipe Data

Pipe Diameter
mm
Orifice Diameter
mm
Pressure Tappings
Pressure Range
bar

Common Results

Pressure Ratio (P2/P1) N/A Pressure Drop Ratio (DP/P1) N/A
Reynolds (ReD) N/A Reynolds Flow Regime N/A
Beta Ratio N/A Discharge Coefficient N/A

Specific Results

Mass Flow Kg/s Mass Flow Kg/h
Volumetric Flow m3/h Normal Flow Nm3/h

Limits of Use

1. Orifice Diameter (d) - The result has not yet been evaluated.
2. Pipe Diameter (D) minimum size - The result has not yet been evaluated.
3. Pipe Diameter (D) maximum size - The result has not yet been evaluated.
4. Beta Ratio (Beta) minimum size - The result has not yet been evaluated.
5. Beta Ratio (Beta) maximum size - The result has not yet been evaluated.
6. Reynolds Number (ReD) - The result has not yet been evaluated.
7. Pressure Ratio - The result has not yet been evaluated.

How the Orifice Plate Find Flow Calculator works?

  • Instrumentation and Control.net
  • Rating: 4.7109 - 1169 reviews
All of our calculators work in a similar way. First you will find a block of information called "Identification Data". In this block we ask you to indicate the Tag, the Plant where the instrument is located and the Area. You also have the possibility to add some notes. This information will be attached to the report if you wish to provide it. It is not necessary to perform the calculation.
The next block of information is called "Fluid Data". In this block we ask you to indicate the the name of your fluid, state of matter, and other properties of your fluid. If you select gas, density is calculated based on the Pressure, Molecular Weight and Temperature properties.
The last input block is called "Pipe Data". A set of cells defining pipe data in a restriction orifice calculation includes parameters such as pipe diameter, orifice diameter and flow properties, which are used to evaluate pressure drops, flow rates, and orifice sizing accurately.
Once everything is set you must click on Calculate! button. Then, all the resulting cells will be calculated. You can press this button until your results are inline with your expectations. Once everything is correct you can export your work to an ISA S20 format spreadsheet containing all your parameters and results. To be able to obtain this file you must click on Download button.
We hope you enjoy using this calculator.

Information and Definitions

Used Equation
Formula
Dimensional Analysis
Formula
Beta Ratio The ratio of the orifice diameter to the pipe diameter, affecting flow restriction and pressure drop. It is essential in flow measurement, with specific ratios optimizing accuracy for different flow ranges.
Common Results Refers to standard calculations and outputs in fluid mechanics, such as flow rate, pressure drop, and velocity, essential for analyzing system performance and determining if the design meets operational requirements.
Contraction Coefficient A factor representing the reduction in cross-sectional area in a flow contraction, influencing flow speed and pressure. It is used in flow calculations involving orifices and sudden changes in pipe diameter.
Critical P Ratio The critical pressure ratio is the ratio of downstream to upstream pressure at which gas flow becomes choked, meaning maximum flow rate is reached. It is essential in designing nozzles and controlling flow in compressible fluid systems.
Density Density is the mass per unit volume of a fluid, typically measured in kg/m3. It impacts fluid behavior, such as buoyancy and pressure. High-density fluids exert greater pressure in systems, influencing design parameters in piping and fluid transport applications.
Dynamic Viscosity Dynamic viscosity is a measure of a fluid's resistance to shear or flow, measured in Pascal-seconds (Pa s) or centipoise (cP). It affects how easily a fluid flows through pipes and around objects, influencing energy requirements in pumping systems.
Fluid Data Refers to essential information about a fluid, including properties like density, viscosity, and specific heat. This data is crucial for calculating flow rates, pressure drops, and heat transfer in systems. Fluid data helps engineers understand fluid behavior under different conditions, which aids in designing efficient systems in industries like oil, gas, and water treatment.
Limits of Use Defines the operational boundaries, like maximum pressure or temperature, for a system. Staying within these limits ensures safe, efficient operation and protects equipment from damage or failure.
Mass Flow (Kg/h) The amount of fluid mass passing through a point per hour. It is critical for measuring fluid transport, affecting system sizing, energy requirements, and overall efficiency in industrial processes.
Mass Flow (Kg/s) Mass flow in kg/s indicates fluid mass per second, important for real-time flow control and energy calculations in fast-moving fluid systems, especially in high-demand applications like power generation.
Molecular Weight Molecular weight is the mass of a molecule of a substance, measured in atomic mass units (amu). In fluid mechanics, it helps calculate the density of gases and affects the fluid's compressibility and flow characteristics, particularly for gases in dynamic systems.
Operating Pressure The pressure at which a system operates, influencing fluid density and flow rate. Higher pressures increase fluid density in gases, affecting flow calculations and system integrity. Operating pressure is crucial for safety, efficiency, and equipment durability in fluid systems.
Operating Temperature The temperature at which a fluid operates within a system, influencing its viscosity, density, and flow behavior. Higher temperatures generally decrease fluid viscosity, affecting the resistance to flow, and can also impact material compatibility and safety limits.
Orifice Diameter The diameter of an orifice or opening in a pipe, often used in flow measurement. It restricts flow, creating a pressure difference used to calculate flow rate, with smaller diameters increasing pressure drop and reducing flow.
Pipe Data Refers to the dimensions, materials, and specifications of piping systems, affecting fluid dynamics, resistance, and capacity. Pipe data is essential for designing efficient fluid transport systems and calculating parameters like flow rate and pressure drop.
Pipe Diameter Pipe diameter is the internal width of a pipe, influencing flow rate, velocity, and pressure drop. Larger diameters reduce friction and resistance, improving flow efficiency but requiring more space and higher installation costs.
Pressure Drop Pressure drop is the reduction in fluid pressure as it flows through a system, caused by friction, restrictions, or changes in elevation. It is a key factor in energy loss and pump selection in fluid systems.
Pressure Drop Ratio The ratio of pressure drop across an element to the inlet pressure. It helps assess energy losses and efficiency in a system, with high ratios indicating significant pressure loss and potential flow restrictions.
Pressure Ratio The ratio of outlet pressure to inlet pressure, used to describe pressure changes across systems. It is crucial in analyzing compressible flows, particularly in gas systems, to determine flow characteristics and efficiency.
Ratio of Sp.Heats The ratio of specific heats, or heat capacity ratio (kappa), is the ratio of a fluid's specific heat at constant pressure to its specific heat at constant volume. It affects compressible flow and is critical in calculations involving gases and thermodynamics.
Reynolds Flow Regime The classification of flow as laminar, transitional, or turbulent based on the Reynolds number. It affects flow behavior, pressure drop, and efficiency, guiding the design and operation of fluid systems.
Reynolds Number A dimensionless number indicating whether a fluid flow is laminar or turbulent, calculated from fluid velocity, density, viscosity, and characteristic length. It helps predict flow patterns and friction losses in pipes and channels.
Specific Results Refers to calculated values unique to a system's conditions, such as specific flow rates or pressure conditions, essential for verifying that the system operates within desired parameters for performance and safety.
State of Matter Defines the physical state of a substance: solid, liquid, or gas, determined by temperature and pressure. In fluid mechanics, the state of matter affects fluid flow, density, and viscosity. Gases are compressible, liquids nearly incompressible, and each state behaves uniquely under dynamic conditions.
Velocity in Pipe The speed of fluid movement through a pipe, influenced by pipe diameter and flow rate. It affects pressure drop, energy losses, and is crucial for sizing pipes to avoid excessive turbulence or friction.
Volumetric Flow The volume of fluid passing through a point per unit time, often in m3/h. It is used in pump sizing, system efficiency calculations, and to ensure fluid supply meets demand in various processes.

Orifice Plate Find Flow Calculator References

1 International Organization of Standards (ISO 5167-1). 2003. Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 1: General principles and requirements.
2 International Organization of Standards (ISO 5167-2) 2003. Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full -- Part 2: Orifice plates.
3 American Society of Mechanical Engineers (ASME). 2001. Measurement of fluid flow using small bore precision orifice meters. ASME MFC-14M-2001.
4 U.S. Dept. of the Interior, Bureau of Reclamation, 2001 revised, 1997 third edition, Water Measurement Manual.
5 Michael Reader-Harris (2015) Orifice Plates and Venturi Tubes.
6 Miller, R. W., Flow Measurement Handbook, 3rd ed., McGraw-Hill, New York, 1996.
7 American Gas Association, AGA Gas Measurement Manual, American Gas Association, New York.
8 Wikipedia
9 Corrosionpedia
10 Orifice Plates and Venturi Tubes (2015) - Michael Reader-Harris
11 EMERSON Fundamentals of Orifice Meter Measurement
12 Search Data Center

Another calculators or articles that may interest you ...

1 In Flow Rate Calculator you can calculate the volumetric flow rate of any liquid or gas through a specific pipe diameter and download results.
2 Pressure Measurement, a comprehensive guide to pressure measurement principles and techniques.
3 Orifice Plate Calculator-Find Orifice Size is an useful tool to calculate the size of an orifice plate.
4 Density of Common Liquids Table, an easy reference table for liquid density data.
5 Absolute Viscosity of Common Gases, is a table that represents the absolute viscosity of some common fluids and his evolution against the temperature.
6 This is a table of specific heats' ratio for common gases: Heat Capacity Ratio of Common Fluids
7 Molecular Weight Common Fluids Table, an easy reference table for molecular weight data.

Frequently Asked Questions

Q1 What are the advantages of using an orifice plate for flow measurement?
A1 Orifice plates are widely used due to their simplicity, low cost, and ease of installation. They do not have any moving parts, which minimizes maintenance requirements. They can be used for a wide range of fluids, including gases, liquids, and steam. Orifice plates also provide reasonably accurate measurements when properly installed and maintained. Additionally, they are compatible with differential pressure transmitters, allowing for easy integration into existing systems. Their standardization and availability in different materials make them suitable for various industrial applications, including oil and gas, water treatment, and chemical processing.
Q2 What are the limitations of an orifice plate in flow measurement?
A2 Orifice plates cause a permanent pressure drop, which can reduce system efficiency. Their accuracy is affected by wear, corrosion, and incorrect installation. They require a straight pipe section upstream and downstream for reliable readings. Orifice plates are also sensitive to flow disturbances, and errors can arise from improper beta ratio selection. Their performance in low-flow conditions is not ideal, as small variations in flow may not be accurately captured. Compared to other flow measurement devices, they may have lower accuracy and require frequent calibration in demanding applications.
Q3 What factors affect the accuracy of an orifice plate?
A3 Several factors influence the accuracy of an orifice plate. Proper installation, including alignment and positioning within the pipeline, is crucial. The condition of the orifice plate, including surface roughness and edge sharpness, impacts measurements. The beta ratio, which is the ratio of orifice diameter to pipe diameter, must be appropriately selected. Flow disturbances, caused by bends, valves, or fittings, can introduce errors. Adequate straight pipe lengths upstream and downstream help ensure accuracy. Temperature, pressure fluctuations, and fluid properties, such as viscosity and density, also play a role in measurement precision.
Q4 What is an orifice plate and how does it measure flow?
A4 An orifice plate is a thin, flat plate with a precisely machined hole, installed within a pipe to create a flow restriction. As fluid passes through the orifice, its velocity increases while pressure decreases, creating a differential pressure across the plate. This pressure difference is measured using a differential pressure transmitter, which correlates with the flow rate. The flow rate is then determined using established equations based on fluid properties and orifice geometry. Orifice plates operate on the principle of Bernoullis equation and are commonly used in industries to measure gas, liquid, and steam flow.
Q5 What is the beta ratio in an orifice plate?
A5 The beta ratio is the ratio of the orifice diameter to the internal pipe diameter. It is a critical parameter in orifice plate flow calculations. A typical beta ratio ranges from 0.2 to 0.75, with values outside this range leading to reduced accuracy. A low beta ratio results in higher pressure loss and increased sensitivity to flow disturbances, while a high beta ratio may cause excessive velocity and turbulence. The beta ratio influences discharge coefficient and flow measurement uncertainty. Proper selection ensures accurate measurement and minimizes pressure drop while maintaining reliable flow calculations.
Q6 What is the purpose of the vena contracta in orifice plate flow measurement?
A6 The vena contracta is the point downstream of the orifice where the fluid stream has its smallest cross-sectional area and highest velocity. It forms due to the fluid inertia and pressure drop created by the orifice restriction. The pressure difference between the upstream section and the vena contracta is measured to determine the flow rate. Understanding the vena contracta location is important for accurate pressure tapping placement. Incorrect tap positioning can introduce errors in differential pressure measurement, affecting flow rate calculations. The vena contracta effect also influences discharge coefficient values.
Q7 What types of orifice plates are commonly used?
A7 Several types of orifice plates exist, each designed for specific applications. The most common is the concentric orifice plate, which features a centrally located hole and is widely used in industrial flow measurement. Eccentric orifice plates have an off-center hole, making them suitable for measuring slurries or fluids with particulates. Segmental orifice plates have a semi-circular opening, used for similar applications. Quadrant edge orifice plates are designed for measuring viscous fluids and provide improved accuracy at low Reynolds numbers. The choice of orifice plate depends on fluid type, flow conditions, and system requirements.
Q8 Where should pressure taps be placed for an orifice plate?
A8 Pressure taps must be correctly positioned to ensure accurate differential pressure measurement. The most common configurations include flange taps, which are located one pipe diameter upstream and downstream of the orifice. Corner taps are placed directly at the orifice plate, commonly used in small pipes. D-D/2 taps are positioned one diameter upstream and half a diameter downstream, providing a reliable measurement in larger pipelines. Pipe taps, placed farther from the orifice, are used in older systems but are less accurate. Correct tap placement minimizes errors and ensures consistent flow measurement performance.
Q9 Why is a straight pipe section required before and after an orifice plate?
A9 A straight pipe section is necessary to ensure stable, uniform flow before it reaches the orifice plate. Flow disturbances from elbows, valves, pumps, and fittings create turbulence, which affects pressure distribution and measurement accuracy. Adequate straight lengths allow flow to stabilize, ensuring that the differential pressure reading correctly represents the flow rate. The recommended upstream and downstream pipe lengths depend on beta ratio and pipe configuration. Typically, ten to twenty pipe diameters upstream and five to ten diameters downstream are required for optimal performance, reducing measurement uncertainty and improving accuracy.
Q10 Why is an orifice plate flow meter considered a differential pressure device?
A10 An orifice plate flow meter measures flow by creating a pressure drop across a restriction. It operates on the principle of differential pressure measurement, where the difference between upstream and downstream pressures is proportional to the flow rate. This pressure difference is detected using a differential pressure transmitter, which converts it into an electrical signal for flow rate calculation. Because it relies on pressure changes rather than direct velocity or volume measurements, it falls under the category of differential pressure flow meters. This method is widely used due to its simplicity, reliability, and compatibility with various fluids.