Fundamentals of Flowmeters

John McCutcheon January 2014

What are Flowmeters? Instruments to

measure Linear Nonlinear Mass or Volumetric

flow rates of liquid or gas.

Why is flow measurement vital?

Industrial sectors Water supply Oil extraction Gas distribution Pharmaceutical industry

Types of Flow Measurement Mass flow rate

Volume flow rate

Flow Fluid MeasurementsVolumetric Flow Rate

Q = VTQ = volume x time

Q = V x A Flow = velocity x area V = Q * TVolume = flow x time

Fluid Flow MeasurementsReynolds Number

(Re) = p x D * v/u

p = densityD = internal pipe diameterV = velocityU = dynamic viscosity

Types of Flow

Laminar Transition Turbulent

Laminar Flow

Transition Flows

Turbulent Flow

Flow of Fluid

Factors affecting flow of fluid:

Velocity – speed fluid moves Viscosity – ease of flow of fluid Density – weight per unit volume

Flow Meter Types

Flow Meter Types

Flow Meter Types

Flow Meter Types

Flow Meter Investigation(Variable Area Flow Meter)

Advantages

Disadvantages

Applications

Mass Flow Meter Advantages

Disadvantages

Applications

Coriolis Flowmeter Advantages

Disadvantages

Applications

Differential Pressure Meters Advantages

Disadvantages

Applications

Turbine Meter Advantages

Disadvantages

Applications

Flow Meter Selection Reasons What is the fluid being

measured by the flowmeter or f lowmeters (air, water, etc.)?

If i t is not water, what viscosity is the l iquid?Is the fluid clean?

If this is a process application, what is the size of the pipe?

What is the minimum and maximum process pressure?

What is the minimum and maximum process temperature?

Is the fluid chemically compatible with the flowmeter wetted parts?

Calibration Must be done

conditions of actual operation.

Performed by a certified company.

Types Of Calibration

Wet calibration

Standing start and finish method

Reasons For Calibration Deposit on internal

surfaces Contamination Chemical attack Abuse Aging

Electrical changes Mechanical changes Fluid property

differences Improper instilation External influences

Calibration Time scale When should these

be calibrated?

Does time play a factor?

Do they require to be calibrated?

Summary Of Investigation

Any questions?