Micro Motion Guide: Guidelines for the Selection and Operation of Provers with ELITE Coriolis Flow Meters Manuals & Guides

Reference Guide

MC-001597 Rev E

1/2018

ELITE® Coriolis Flow Meters

Guidelines for the Selection and Operation
of Provers with Micro Motion ELITE

®

Coriolis

Flow Meters

Micro Motion® ELITE® ow meters are high-

precision Coriolis ow meters that are often used
in the oil and gas industry in conjunction with
volume provers. These guidelines are designed to
aid in the selection of a prover size that will result
in consistent proving repeatability, while taking
into consideration the balance between:

• Maximum proving efciency

• Minimum prover size and cost

• Minimum prover wear and maintenance

Substantial experience from laboratory testing and
eld proving forms the basis of the prover size
recommendations and the Total Prove Time (TPT)
predictions in these guidelines. However, results
may vary if unstable process conditions exist
during proving.

It should be noted that these guidelines are based
on conservative estimates from the available data.
If repeatability requirements are already consis­tently being met, there is no need to change the
process or the prover size.

Proving Methods and Proving Data Evaluation

The American Petroleum Industry (API) Manual
of Petroleum Measurement Standards (MPMS)
Chapter 4.8, Second Edition, Operation of Proving
Systems, Annex A, Evaluating Meter Proving
Data explains the relationship between the number

of proving runs, the observed repeatability, and the
random uncertainty of the resulting meter factor.
One important principal is that a lower meter factor
uncertainty will always result as more runs are
collected and averaged.

Prover Sizing and Selection for Fixed­Volume Provers (Does Not Apply to Master
Meter Provers)

Important Note: The prover size should never
result in a pass time of less than 0.5 seconds or
a pre-run time of less than 0.25 seconds.

Total Prove Time (TPT) is dened as the total

accumulated amount of time during which the
prover displacer was travelling between the detector
switches. The minimum TPT that is needed to
achieve the target meter factor random uncertainty
can be used to size the prover.

Estimated minimum TPT values that may be
expected to pass repeatability requirements for

different meter sizes and ow rates are shown in
Table 1. The velocity of the uid as it travels through
the meter ow tubes is also shown in Table 1 in

units of feet per second (fps). Velocities above
60 fps are not recommended when proving with

a xed-volume prover and may result in excessive

TPT to pass repeatability. For applications above
60 fps, master meter proving is recommended
instead of xed-volume provers.

Equation 1 describes TPT:

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Base Prover Volume(BPV)

𝑇𝑃𝑇 

Flow rate

×(# 𝑜 𝑟𝑢𝑛𝑠󰇜 × (# 𝑜 𝑝𝑎𝑠𝑠𝑒𝑠 𝑝𝑒𝑟 𝑟𝑢𝑛󰇜

Reference Guide

MC-001597 Rev E

1/2018

ELITE® Coriolis Flow Meters

To use Table 1 to size a prover, there are two
methods to select from:

Method 1 (Determine the BPV): Find the minimum

TPT value from Table 1. Multiply the ow rate by

0.0117 to convert from BPH to gallons per second.
Then enter the TPT, ow rate, the number of runs,

and the passes per run (if averaging multiple passes

per run) into Equation 2 to nd the minimum BPV

needed in gallons.

Equation 2:

𝐵𝑃 

TPT x Flow Rate

(# 𝑜 R𝑢𝑛𝑠󰇜×(Passes pe Run󰇜

Example: CMFHC4 meter at 6500 BPH

• From Table 1: Velocity ≈ 30 fps. TPT =

20 seconds.

• Convert: 6500 BPH X 0.0117 = 76 gallons
per second

• If 5 single-pass runs are required, BPV =
(20 seconds X 76 gallons per second)
÷ (5 runs X 1 pass per run) = 304 gallons
or 7.2 BBLS.

• If 10 runs and 3 passes per run are acceptable,
BPV = (20 seconds X 76 gallons per second) ÷
(10 runs X 3 pass per run) = 50 gallons or

1.2 BBLS.

Method 2 (Determine the Number of Passes
Needed): Find the minimum TPT value from

Table 1. Multiply the ow rate by 0.0117 to convert
from BPH to gallons per second. Then, insert
the ow rate and a BPV in gallons into Equation

3 to estimate the total number of passes that

will be needed for a prover size with that BPV. If

averaging multiple passes per run, divide the total
number of passes needed by the number of runs
and round up to determine the minimum number

of passes per run needed. For single-pass runs,

the number of runs needed will equal the total
number of passes needed.

Equation 3:

𝑇𝑜𝑡𝑎 # 𝑜 𝑃𝑎𝑠𝑠𝑒𝑠  𝑇𝑃𝑇×

Flow rate

Base Prover Volume(BPV)

Example: CMF400 meter at 2300 BPH

• From Table 1: Velocity ≈ 40 fps. TPT ≈

30 seconds.

• Convert: 2300 BPH X 0.0117 = 27 gallons
per second

• If the BPV is 170 gallons (4 BBLS), Total #
of passes = 30 seconds X 27 gallons per
second ÷ 170 gallons = 5 total passes

(5 total passes ÷ 5 runs = 1 pass per run

for 5 runs).

Page 2

• If the BPV is 65 gallons (1.55 BBLS), Total # of
passes = 30 seconds X 27 gallons per second
÷ 65 gallons = 12 total passes

(12 total passes ÷ 5 runs = 3 passes per
run for 5 runs).

Reference Guide

MC-001597 Rev E

1/2018

ELITE® Coriolis Flow Meters

Table 1. Estimated Minimum Total Prove Time (TPT)

Values shown are the velocity inside the meter in feet per second (fps)

followed by the Total Prove Time (TPT) in seconds.

TPT = prover pass time X passes per run X runs per proving*
(*total number of runs required to reach ±0.027% meter factor uncertainty may vary.)

Page 3

Reference Guide

MC-001597 Rev E

1/2018

ELITE® Coriolis Flow Meters

• The liquid inside the piping connecting the meter
to the prover should remain stable.

o

Minimize piping between the meter and

prover.

o

Avoid dead-end branches between

meter and prover that may act as a volume

“spring” with compressible uids.

• Sufcient back pressure must be maintained on

both the prover and the meter to avoid vapor

breakout and to maintain a stable ow rate during
displacer launch and travel. Minimum recom­mended back pressure is shown by Equation 4
(from API MPMS Ch. 5.6).

Table 1 (cont.) Estimated Minimum Total Prove Time (TPT)

Increasing the BPV will result in meeting the mini-

mum TPT with fewer passes. Increasing the number
of passes will allow reaching the minimum TPT with
a smaller prover. A decision may be made either to

size the prover with a smaller BPV (lower capital

investment) with a longer overall proving time, or

with a larger BPV with reduced runs (less long-term

wear and tear) and shorter overall prove time.

Prover Conditions

It is important to prove at conditions that are as
similar as possible to the expected operating con­ditions. There are many conditions and factors that

can inuence the success of proving systems.

• Prover equipment and all supporting reference

measurement devices must be well-maintained
and veried to ensure measurement traceability,

reproducibility, and repeatability (API MPMS Ch. 4
and Ch. 21.2, paragraph 2.11).

• Stability of ow rate, density, temperature, and

pressure is critical during proving. System design,
prover settings, and maintenance can all impact

ow rate stability during proving.

Equation 4: ρb ≥ 2 Δρ + 1.25 ρ

e

Where: ρb = Minimum back pressure (psig)

ρ = Pressure drop across meter at max.

Δ

ow rate

ρ

= Equilibrium vapor pressure at

e

operating temperature (psia)

• Accurate prover density measurement is crucial
when mass proving with a volumetric prover.
The following tolerances are advised when using
a pycnometer (API MPMS Ch. 14.6).

o

Max. temperature difference = 0.2 °F

o

Max. pressure difference = 1 psi

o

Density Meter Factor (DMF) repeatability

should be 0.05% or better between consecutive

pycnometer tests

• Flow pulsation from PD pumps, including lack
of back-pressure regulation, may inuence

repeatability and additional passes may be
needed to meet random uncertainty requirements.

• Enabling compensation for the effect of pressure

on the meter (consult the Transmitter Congura-

tion and Use Manual) can improve repeatability
in applications where line pressure varies by
more than 30 psig during proving runs.

Page 4

Reference Guide

MC-001597 Rev E

1/2018

ELITE® Coriolis Flow Meters

API MPMS Chapter 5.6 Measurement of Liquid
Hydrocarbons by Coriolis Meters denes a pulse

scaling factor (PSF) as the number of pulses output

by a Coriolis meter per unit of ow. In this way, a
Coriolis meter PSF is like a mechanical meter’s
K-factor, but adjustable.

Micro Motion transmitters typically provide a fre­quency output of up to 10,000 Hz (10,000 pulses per
second). Many eld device pulse input specications

have a similar maximum pulse input rate of 10,000

Hz. However, some eld devices have a maximum
pulse input rate that is less than 10,000 Hz. The
PSF of the Coriolis owmeter can be adjusted to
stay within the constraints of any eld device that is

counting the pulses from the meter per the equations
shown here:

Meter Operation

When using smaller provers, it is important to ensure

that the meter is congured for optimum ltering and

speed of response.

1. Select the fastest speed of response available:

o

5700 transmitter: select “Low Filtering”

response mode

o

2700 transmitter: select “Special” for Update

Rate and either “Special” or “Low Filtering”

for Calculation Speed

2. Set ow damping to a value between 0.0 and

0.08 seconds.

3. Set density damping to 0.16 seconds.

• Proving Wizard software is available from
Emerson to aid in preparing Micro Motion
Coriolis meters for proving

Coriolis owmeters do not have a xed K-factor
(number of pulses output per unit of ow). The
number of pulses output per unit of ow (e.g. pulses

per barrel) from a Coriolis meter is an adjustable
parameter that can be set to any desired value.

However, the frequency of pulses during the highest
ow rate must not exceed the pulse input capacity

of the prover pulse counting device.

When the meter factor remains stable between
proving events, this indicates that the meter zero
setting value is good. A change in the meter factor
may or may not be related to the meter zero, so it is

important to always perform a Zero Verication Test
(consult Transmitter Conguration and Use manual)
before making any zero adjustments. Only adjust the
meter zero if advised to by the Zero Verication Test.

If a meter zero is adjusted, reprove the meter.

Page 5

Reference Guide

MC-001597 Rev E

1/2018

Master Meter Proving

Micro Motion Coriolis meters can be used as master

meters per API MPMS Ch. 4.5 for proving with the

following advantages:

• A Coriolis master meter can be used to prove in
either volume and/or mass units.

• Pass duration can be lengthened to improve
repeatability.

• Maintaining stable process conditions is much
easier with no effects due to a displacer launch.

• Low maintenance and high reliability, with no
seals or moving parts.

ELITE® Coriolis Flow Meters

Need More Information?

Emerson has extensive eld experience in mass

and volume proving of our Micro Motion Coriolis meters.

Contact us at 1-800-522-6277 or visit our website at

www.MicroMotion.com

Emerson Automation Solutions

7070 Winchester Circle
Boulder, CO USA 80301
T [phone]
F [phone]

www.Emerson.com

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