a first review of calibration devices acceptable for metrology laboratory
DESCRIPTION
A FIRST REVIEW OF CALIBRATION DEVICES ACCEPTABLE FOR METROLOGY LABORATORY. Mr Drago GROSELJ Dr Jérôme DUVERNOY Dr John GORMAN www.arso.sigov.si www.meteo.fr www.bom.gov.au [email protected] [email protected] [email protected]. - PowerPoint PPT PresentationTRANSCRIPT
A FIRST REVIEW OFCALIBRATION DEVICES ACCEPTABLE
FOR METROLOGY LABORATORY
Mr Drago GROSELJ Dr Jérôme DUVERNOY
Dr John GORMAN
www.arso.sigov.si www.meteo.fr
www.bom.gov.au
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Specialization
PRESSURE
TEMPERATURE
HUMIDITY
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PRESSURE
Primary Pressure Standard
M = Mass
P = Piston
C = Cylindre
Weight = Pressure
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PRESSURE
Primary Pressure Standards
Dead weight gauge
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PRESSURE
Advantages:
– Traceability to mass and length
– Long term stability
– Accuracy, reproducibility, reliability and stability
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PRESSURE
Disadvantages:
– Time consuming
– Measurements corrections (T, g, U…)
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PRESSURE
Secondary Pressure Standard
Quartz Barometer
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PRESSURE
Advantages:
– Faster and easier to use
– Easy to adapt to automatic operation
– Generally less expensive
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PRESSURE
Disadvantages:
– Not a basic measurement
– Higher measurement uncertainty
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PRESSURE
Travelling pressure standard
An example of electronic barometer
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PRESSURE
Calibration systems
example of a barometric chamber
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PRESSURE
Calibration systems
example of a pressure generator
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TEMPERATURE
EIT 90
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METEOROLOGY
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TEMPERATURE
EIT 90
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Gallium
Mercury
Water
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TEMPERATURE
Standard Platinum Resistance Thermometer (SPRT)
Example of an SPRT
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TEMPERATURE
Means of calibration
Stirring bath
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TEMPERATURE
Means of calibration
Climatic chamber
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HUMIDITY
Humidity Generators
Two Pressure Humidity Generator
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HUMIDITY
Humidity Generators
Split stream system
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HUMIDITY
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Climatic Chambers
Environmental Chamber
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HUMIDITY
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Climatic Chambers
Split stream chamber
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HUMIDITY
Salt Solutions Generator
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Salt/Temperature oC 5.0 10.0 15.0 20.0 25.0
Lithium chloride 11.3 11.3 11.3 11.3 11.3
Magnesium chloride 33.6 33.5 33.3 33.1 32.8
Potassium carbonate 43.1 43.1 43.1 43.2 43.2
Sodium bromide 63.5 62.2 60.7 59.1 57.6
Sodium chloride 75.7 75.7 75.6 75.7 75.3
Potassium chloride 87.7 86.8 85.9 85.1 84.3
Potassium sulphate 98.5 98.2 97.9 97.6 97.3
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HUMIDITY
Salt Solutions Generator
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The salt solution system at Meteo France
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HUMIDITY
Approximate Uncertainties
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HUMIDITY
Recommendations– The target uncertainty within a calibration laboratory = 2 % RH (0.3 oC dew point)
– Labs should have a humidity generator or chamber:
within the range 5 % RH at 15 oC to 90 % at 40 oC.
– The streams or parcels should be stable to within ± 0.2% RH per minute
– If the source of humidity is not a first principles device, then measurement of the humidity should be with a dew point hygrometer with an 95 % uncertainty of 0.2oC or better
– Calibration of field humidity probes should be done with a view to maintaining a low overall uncertainty. The whole of measurement cycle, including inspection frequency, must be considered and appropriate levels of calibration uncertainty applied
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CONCLUSION
Some possibilities in terms of calibration. This first review is not exhaustive Every other remaining devices, standard, generator not presented
here are still acceptable Metrology is the science of measurement Expression of the uncertainty
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THE END
THANKS FOR YOUR PATIENCE