Seminar on,

“ CALIBRATION TECHNIQUES FOR MAGMETERS”

Presented By,

Bhushan Patil

Guided By,

Prof. A.S. Kulkarni

P.V.P.INSTITUTE OF TECHNOLOGYDepartment of Instrumentation Engineering

Wide area of useProcess industryChemical plantsPharmaceutical industry

Why Flow meters ?

Obstruction flow meters Velocity flow meters – Including Moving

Member meters Positive Displacement meters Variable area meters Electronic meters

Classification

Process media• Liquid• Gas

Density (Specific Gravity)ViscosityPressureTemperatureVelocity

Factors affecting flow meter performance

Terms Reg. Accuracy, Repeatability

Good Accuracy Means Good Repeatability

Good Repeatability Does Not Necessarily Mean Good Accuracy

Poor Repeatability Means Poor Accuracy

Advantages Over Other Technologies• No moving parts• No pressure drop• Flow rate independent of viscosity,

temperature, and density• Minimum upstream piping requirements• Electronics interchangeable without

regard to size

Why Magnetic Flow Meters ?

• Measure dirty liquids with solids• Electronics interchangeable without regard

to size• Measure highly corrosive fluids• Very large turndown• Linear output

Faraday's Law, states that the voltage induced across any conductor as it moves at right angles through a magnetic field is proportional to the velocity of that conductor.

Working Principle

Mathematical Representation:-

E=K*B*D*VWhere

• E=The induced voltage generated• K=The unit conversion constant• B=The magnetic field strength • D=Distance between the probes• V=velocity of conductor

• No Moving Parts• Very Wide Range ability• Ideal For Slurries• Unobstructed Flow Path

Advantages

• Liquid Must Be Conductive

• Physical Pressure and Temperature Limits

Disadvantages

Calibration is required for:

Testing a new instrument Testing an instrument after it has been

repaired or modified Periodic testing of instruments Testing after the specific usage has elapsed Prior to and/or after a critical measurement

Why should We Calibration ?

When observations are not accurate or instrument indicators do not match the output of a surrogate instrument

After events such as: • An instrument has had a shock, vibration, or

exposure to adverse conditions, which can put it out of calibration or damage it.

• Sudden weather changes

Safety procedureWastagesQuality

Risk Involved in Not Calibrating an Instrument

It is a comparison of measuring equipment against a standard instrument of higher accuracy to detect, correlate, adjust, rectify and document the accuracy of the instrument being compared.

What is Calibration ?

DensityViscosityPressureTemperatureConductivityHazardous or corrosive

Importance of Calibration of fluid and its conditions

Calibration interval

Maintain minimum risk

Calibration Frequency

On sight calibrationLaboratory calibration • GRAVIMETRIC CALIBRATION• VOLUMETRIC CALIBRATIO

Calibration Methods For Liquid

A flow meter can be calibrated gravimetrically by weighing the quantity of liquid collected in a vessel. The vessel is weighed and the weight (in air) of the fluid collected is noted

Gravimetric Calibration

M=W *{ 1+ρair * [ 1 / ρf - 1/ ρw] } Where • M = is the mass (kg),• W = is the measured weight (kg) • ρair = is density of air (kg/m3),

• ρf = is density of the fluid (kg/m3),

• ρw = is density of the calibration

weights (8,000 kg/m3)

Standing start and finish method

Flying Start And Finish Method

The measurement of the quantity of liquid collected may be carried out volumetrically by collecting a known volume of liquid in a container

Volumetric Calibration

Field calibration with radiotracer transit time method

Reference meterTracer methodInsertion meterClamp-on ultrasonic meters

Other Calibration Methods

Meter must be in conditionThere should not any uncertainty

Expectation Of Calibration

• Correct instrument will be adjusted

•More compatible with multifunction calibrators

ADVANTAGES OF INDIVIDUAL CALIBRATION

Entire loop is not verified within tolerance Mistakes on re-connect Less efficient use of time to do one

calibration for each loop instrument as opposed to one calibration for the loop

Disadvantages of Individual Calibration

Chemical industry Water and wastewater Hydraulic transport, liquid products with up to 50%

solids content Paper and wood pulp production Pharmaceutical Food and beverages Filling and dispensing processes Highly abrasive slurries High-pressure industrial processes Partially filled pipelines

Applications

Need of calibration definition of calibrationCalibration of fluid and its conditionsCalibration frequency Methods Expectation Advantages Disadvantages

Overview

Richard Paton,” National Engineering Laboratory, Scotland”, UK

www.ni.com/white-paper/14811/en/pdf www.tuvnel.com NEL Technology for life]www.isa.org/standards-and-publication/

intake-magazine/2010/february/automation-basic-magnatic-flowmeters/technology

References

Thank you