The Calibration of Flow Meters

GOOD PRACTICE GUIDE THE CALIBRATION OF FLOW METERS

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The calibration o ow meters

This good practice guide covers the general principles o calibration when applied to the ow meters meters or devices to measure owing uids, uids, including gas. It provides an overview o methods used in a variety o situations rom calibrations in standards laboratories to those in the feld, including ow meter verifcation in a non-laboratory situation. The guide is aimed at operators o calibration acilities, users requesting calibrations and engineers having to establish a calibration method. Contents Summary

4.3

Pipe provers

18

1

Introduction

2

4.3.1 Uni-direction Uni-directional al sphere prover

19

2

What is Calibration?

2

4.3.2 Bi-directional sphere prover

20

2.1

Calibration

2

4.3.3 Piston provers

20

2.2

Rate, quantity and time

4

4.3.4 Small volume provers

20

2.3

Repeatability and reprodu reproducibility cibility

5

4.3.5 Pulse interpolation

21

2.4

Resolution

6

4.3.6 Operation and calibration o a prover 22

3

4

The Importance o Calibration Fluid and Conditions Conditions6 6

5

Calibration Methods or Gas Flow Meters

23

5.1

Displacement methods

23

3.1

Fluid properties

6

3.2

Flow profle

7

5.1.1 Mercury seal prover

24

3.3

Traceabi raceability, lity, accuracy and uncertai uncertainty nty

7

5.1.2 Soap flm burrette

24

3.4

Accreditation

9

5.1.3 Bell provers

24

3.5

Reporting the result – perormance indicators indicators9 9

5.2

25

3.6

Calibration requency or how oten should a ow meter be calibrated? 12

Gravimetric / pressur pressure, e, volume and temperature methods

5.3

Gas displacement method

26

5.4

Critical ow Ven Venturi-nozzle turi-nozzle (sonic nozzle)

26

Calibration Methods or Liquids

12

4.1

Liquid collection methods

13

4.1.1 Standing start and stop method

4.2

6

Other Calibrat Calibration ion and Verifcation Methods

27

13

6.1

Reerence meters

27

4.1.2 Flying start and fnish

14

6.2

On-site verifcation methods

28

4.1.3 Dynamic collection methods

15

6.2.1 Tracer methods

28

Measurement methods

15

6.2.2 Insertion meters

29

4.2.1 Gravimetric calibrators

15

6.2.3 Clamp-on ultrasonic meters

30

4.2.2 Volumetric calibrat calibrators ors

16

6.3 Unsual volume methods

30

7

Expectations or a Calibration

31

8

Bibliography Bibliograp hy

32

Addendum – Client calibration check list

1

33