Flow Meter Calibration Techniques

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FLOW METER CALIBRATION RECALIBRATION
TECHNIQUES

• By Dime Marine

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FLOW METER CALIBRATION RECALIBRATION

• Flow meter can be calibrated using any of these
  following methods,
• 1, Wet calibration method
  using the fluid flow.
• 2, Flow rate measurement of physical
  dimensions.
• 3, Electronic or mechanical
  dry calibration methods.

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Wet Calibration

• using actual fluid flow, normally provides
  the finest calibration accuracy for a flow meter
  and sees use where accuracy could also be a
  major concern or when the structure of the meter
  doesn't permits itself to any other methods.
  Precision flow meters usually see wet calibration
  at the time of manufacture.
• After maintenance, one must often replace and
  re-calibrates them. The right time interval
  between these calibrations varies relying on the
  users experience with the meter and thus the
  importance of the measurement.
• When performing the calibration according to the
  initial specification of the manufacturer, only
  if the adequate facilities are available.
  Otherwise specify the minimum value you'd wish
  to calibrate, the quantity of points you are
  taking, and thus the fluid viscosity.
• Wet calibrations test performs along with water,
  air, or hydrocarbon fuels using any of these
  standards weight tanks, volumetric tanks, pipe
  provers, or master flow meters.

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Physical Dimensions Standards

• The flow starts quickly to start out the test
  and holds constant during the test, then stops
  at last. Compare the total reading from the flow
  meter with the load or volume you collect and
  calculate the meter performance.
• A static system operates best with flow meters
  that have minimum sensitivity to low flow rates.
  It doesn't shows optimum results with high-end
  digital meter readings, and the errors obtained
  with a short periods of low flow at the
  starting and at end of the test. Because of this
  the static systems aren't widely used.
• A Gravimetric calibration can also be
  utilized during a dynamic mode. By this method,
  the flow is about at a mild rate before the
  start of the test. The initial measurements
  reading performs together to start out the test
  and again, after the required collection
  period, to end the test. Completely dynamic
  systems are limited by speed or response
  consideration and thus the overall difficulties
  used.

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Hybrid Dynamic Start Stop

• The key to the dynamic start-and-stop reading
  system is that the planning of the floodwater
  valve that switches the flow in and out of the
  standard. During a well-designed system, the
  actual diversion time is way smaller than the
  gathering time, and thus the flow pattern through
  the diverted is independent of flow.
• In this context, the limiting factor system
  uncertainty is that the desired accuracy of the
  load or volume standards. With care, you'll
  reduce errors to low values of 0.1 reading under
  laboratory conditions.

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Master Flow Meters

• Perhaps the foremost common method of wet
  calibration is comparing the output of the meter
  under test with one or more flow meters that are
  certified against high-accuracy
  standards, mentioned as master flow meters.
  Youll construct a touch master meter comparison
  test stand at less cost than other wet
  calibration methods.
• If properly designed and maintained, it's capable
  of calibrating flow meters to a tolerance of 1
  reading or less. If you're selecting flow meters
  as masters, consider the required range of the
  test stand, the required accuracy, the properties
  of the test fluid, and thus the allowable head
  loss.