SLIDE 1
BI-DIRECTIONAL FLOW PROVERS
TRUTH IN MEASUREMENT WITH DIRECT TRACEABILITY TO INTERNATIONALLY ACCEPTED STANDARDS
BI-DIRECTIONAL FLOW PROVERS TRUTH IN MEASUREMENT WITH DIRECT - - PowerPoint PPT Presentation
BI-DIRECTIONAL FLOW PROVERS TRUTH IN MEASUREMENT WITH DIRECT - - PowerPoint PPT Presentation
BI-DIRECTIONAL FLOW PROVERS TRUTH IN MEASUREMENT WITH DIRECT TRACEABILITY TO INTERNATIONALLY ACCEPTED STANDARDS WHAT IS A PROVER? An open or closed vessel of known volume that is used as a volumetric reference standard for the calibration of
SLIDE 2
SLIDE 3
WHAT IS A PROVER? An open or closed vessel of known volume that is used as a volumetric reference standard for the calibration of meters in liquid petroleum service. – API Chapter 4 Section 1
SLIDE 4
WHAT IS ITS PURPOSE? In order to eliminate bias, the calibrated volume of a prover is used to determine a meter factor.
SLIDE 5
WHAT IS METER FACTOR?
A meter factor is the ratio obtained by dividing the actual volume proven by the indicated volume registered by the meter. – API Chapter 4
Note: Factors that can influence the meter’s meter factor are flow rate, temperature, viscosity, wear, and contamination. Proving conditions should match operating conditions in order to maintain the most accurate results possible.
Meter Factor =
Prover Volume Meter’s Indicated Volume
_________________
SLIDE 6
BI-DIRECTIONAL PROVER
Launch Chamber Sphere Displacer Detector Switch Four-Way Valve Valve Actuator Detector Switch Receiving Chamber
SLIDE 7
PROVER DESIGN REQUIREMENTS
- Pipe Size, Schedule & Flange Rating
- Sphere Displacer Velocity
- Volume Between Detector Switches
- Four-Way Valve Sizing
- Four-Way Valve Actuator
- Pre-Run Length
SLIDE 8
SPHERE DISPLACER VELOCITY
Note: Minimum Velocity to be no less than 0.5 fps
- Max. V =
BPH x 0.286 (I.D. [in])
___________
2
< 5.0 fps _
=
Example:
- Max. Flow Rate = 3,960 BPH
Pipe Diameter = 16”
- Max. V = 3,960 x 0.286
(16)
2
= 4.42 fps
SLIDE 9
PROVER VOLUME
- Pre-run length
- Distance (volume) between detector switches
Pre-Run Length Distance between Detector Switches
SLIDE 10
LENGTH BETWEEN DETECTORS
- In order to maintain an
uncertainty of +0.01%, at least 10,000 meter pulses should be collected between detector switches.
Distance between Detector Switches
Example:
Meter K-Factor = 2,000 pulses/bbl
- Min. volume to achieve 10,000 pulses (VBS) = 210 gallons
Measuring section pipe inside diameter = 16” Pipe cross sectional area (A) = 1.396 ft Distance between detector switches (VBS/A) = 20.11 ft.
2
SLIDE 11
FOUR-WAY VALVE SIZING
SLIDE 12
FOUR-WAY VALVE SIZING
Example:
- Max. Flow Rate = 3,960 BPH
Pipe Diameter = 10”
- Max. V =
BPH x 0.286 (I.D. [in])
2
< 15.0 fps _
=
- Max. V = 3,960 x 0.286
(16)
2
= 11.33 fps
SLIDE 13
FOUR-WAY VALVE ACTUATOR
- Mechanical
- Electrical
- Hydraulic
Note: The actuator is sized to maintain a reasonable Four-way valve cycle time,
- r Closed to Closed time
(T c-c). This will be used to determine the required prover pre-run length.
SLIDE 14
LENGTH OF PRE-RUN (RP) T
C-‑C ¡
( )
RP=
___
2 + 2 1 SEC x Max V
__
Pre-Run Length
SLIDE 15
LENGTH OF PRE-RUN (RP) T
C-‑C ¡
( )
RP=
___
Example: Actuator Speed (T c-c) = 4.9 Seconds Sphere Velocity (Max V) = 4.42 fps
2 + 2 1 SEC x Max V
RP=
( )
+ 2
__ SEC x 4.42
1 4.9 2
___
= 13.03 ft
__
SLIDE 16
LENGTH OF PRE-RUN (RP)
RP=
Pre-Run Length