Water Flow Comparison Measurements Between Centro Nacional De ...
6th ISFFM
May 16-18, 2006
Water Flow Comparison Measurements between
Centro Nacional de Metrología (Mexico)
and
Physikalisch – Technische Bundesanstalt (Germany)
by using a CENAM 100 mm Double-Turbine Meter Transfer Standard
Dario Alejandro Loza Guerrero1, Rainer Engel2
1Centro Nacional de Metrología – México.
aloza@cenam.mx
km 4,5 Carretera a los Cués, El Marqués, 76900, Querétaro, México
2Physikalisch-Technische Bundesanstalt
Bundesallee 100, D-38116 Braunschweig, Germany
rainer.engel@ptb.de
Abstract
This comparison test program 2004 CENAM - PTB was in order to assess the confidence and performance of
the Mexican primary standard for liquid flow measurement. This program was an initiative from Centro
Nacional de Metrología (CENAM) in Mexico in collaboration with the Physikalisch-Technische Bundesanstalt
(PTB) Liquid flow laboratory in Germany.
We expected that the results differences between PTB and CENAM were inside CENAM’s uncertainty limits,
nevertheless test results from both laboratories, confirm that the measuring capabilities of meter 2 (MTR 2)
are insufficient to accomplish the objective brought up above. Moreover, MTR 2 had a negative influence over
the fluid velocity profile in configuration 1, causing an awkward response on the downstream turbine meter
(MTR 1).
In summary, the outcomes obtained from MTR 1 are the best reference to analyze the agreement in terms of
liquid flow measurements between such NMIs and those are showed in the following pages.
1. Introduction
the last week of November 2004 and finally returned
it and re-calibrated at CENAM in December 2004.
The comparison was initiated by CENAM in 2004
under the flow measurement assurance program
The estimated expanded uncertainty U for CENAM
with PTB to maintain confidence in the results of the
volumetric flow rate measurements is nearly
fluid flow measurements processes at the water flow
constant all through the flow range of 1,5 m3/h to
facility in Mexico. A comparison between 720 m3/h (± 0,04 % with U determined from a
laboratories was carried out in water, using a two
combined standard uncertainty and a coverage
CENAM 100 mm turbine meters in tandem.
factor k based on t-distribution for ν degrees of
freedom with a level of confidence of approximately
Measurement assurance programs are efforts to
95 percent).
provide confidence in the results of the liquid flow
measurements. To evaluate the systematic errors
for CENAM's liquid flow laboratory we used the
comparison program, all the procedures, system
components and people are evaluated entire.
This package was calibrated at CENAM in Mexico
during early November 2004, thereafter at PTB in
1
6th ISFFM
May 16-18, 2006
2 Objective
Table 1. Main features of CENAM water flow
The main objective of this comparison program is to
standard facility
achieve international agreement in liquid flow
measurements, i.e.: to establish realistic traceability
Features Item(s)
Characteristics
of liquid flow measurement, to estimate the
Flow rate meters
Volumetric flow rate
and
uncertainty of the laboratory and its routine
Mass flow rate
Measurands
volume and mass
procedures, identify the systematic differences
Volume (totalized)
flow totalizing
between laboratories and to build up confidence
Mass (totalized)
meters
between Germany and Mexico.
Operation control
Calibrations
In order to comply with these conditions is
Flying Start / Finish
via:
mode
necessary to have comparison test programs
Diverter valve
periodically between NMIs.
Gravimetric
Weigh systems:
calibration
10 000 kg and
(static weighing)
1 500 kg.
Reference
standards
Volumetric calibration
Pipe prover and
3 The participants - National Metrology
volumetric provers
Institutes (NMIs)
(500 L and 1 000 L)
Variable pressure in
Operation
calibration line
3.1
Centro Nacional de Metrología (CENAM)
Pump direct operation
modes
(approx: 0,2 MPa,
up to 1 MPa)
The liquid flow facilities at CENAM constitutes
Meter / pipe sizes
DN 25 … DN 100
Mexico’s primary standard for liquid flow (25 mm to 200
Line A
DN150 … DN 200
measurements. The system is based on the static
mm)
Line B
(Up to DN 250)
weighing principle with weighbridges of 1,5 tons and
Ranges of flow
Line A
1,5 m3/h to 240 m3/h
10 tons (figure 1 and table 1).
rate
Line B
36 m3/h to 720 m3/h
Expanded
This primary fluid flow system not only serves as a
± 0,03 %,
mass
measurement
± 0,04 to ± 0,05%
volume.
basis for the national chain of traceability but also as
uncertainty
an important facility for fluid flow research.
Flow straightening
45 m
section
All piping and components in contact with the liquid
are made of stainless steel.
3.2
Physikalisch-Technische Bundesanstalt
The PTB Hydrodynamic Test Field, which
represents a high-accuracy water flow calibration
facility, serves as a national primary standard for
liquid flow measurements. This system is based
upon a static weighing principle which incorporates
3 dual-balance weighing systems: 30 tons, 3 tons
and 300
kg. The total expanded measurement
uncertainty of ± 0,02 % (figure 2 and table 2) [2].
Figure 1. The liquid flow facilities at the Centro
Nacional de Metrología.
2
6th ISFFM
May 16-18, 2006
4
The Transfer Standard
In each laboratory the 100 mm turbine meters was
installed in tandem, configuration 1 as shown in
Figure 1, with an additional 100 mm pipework from
each laboratory upstream and downstream of the
assembly to calibrate the flow meters
simultaneously. The flow meters were shifted to
configuration 2 to be calibrated under the same
conditions.
Table 3. Turbine meters specifications.
Turbine meters
MTR 1
MTR 2
Manufacturer
Brooks Instrument
XO Technologies
Model T04AAA1NA1AAAAA
4-81AF5C2-A
Serial number
9812-37510-1-1
211517
Size (mm)
100
100
Material
Stainless steel
Stainless steel
Range (m3/h)
29,4 to 294
Nominal K factor
6 538,79
12 855,77
(pulses/ m3)
The overall length of the “artifact” is 2,90 m. The
Figure 2. The liquid flow facility at the Physikalisch-
pipe work has ANSI 150 flanges.
Technische Bundesanstalt.
Table 2. Features of the PTB standard facility.
5
Test Measurements
Plant
Item(s) Characteristics
features
The test program proposed by CENAM consists of:
Volumetric flow rate
Flow rate meters
• An initial set of tests at CENAM (to quantify
Mass flow rate
and
Measurands
the performance of the two 100 mm turbine
Volume (totalized)
volume and mass flow
meters),
Mass (totalized)
totalizing meters
• A set of tests at PTB, and
Operation control via:
Calibrations
•
flying Start / Finish
Diverter
A follow-up set of tests at CENAM to
modes
standing Start / Finish
On/Off valve
evaluate any changes that may have
Balances: 30 t, 3 t, and
occurred after the initial test at CENAM.
Gravimetric calibration
0,3 t.
• Both laboratories were collect data at 3 flow
Reference
(static weighing)
standards
rates: (50, 150, 250) m3/h.
Volumetric calibration
Pipe prover
A test program takes into account:
Constant pressure in
Via constant-head
calibration line (approx:
Operation
tank
0,35 MPa)
1. All the results generated from the established
modes
Variable pressure in
calibration procedures in each laboratory.
Pump direct operation
calibration line (approx:
0,6 MPa)
2. The data generated via comparison was
Meter / pipe
Line A
DN 200 … DN 400
analyzed in the following way:
sizes
Line B
DN20 … DN 150
• The
average
meter
factors will be analyzed
Ranges of
Line A
3 m3/h to 2 100 m3/h
flow rate
Line B
0,3 m3/h to 350 m3/h
for each of the flow rates selected and for
Expanded
each of the meter configurations.
(operation via
measurement
± 0,02 %
•
constant-head tank)
En number [3].
uncertainty
3
6th ISFFM
May 16-18, 2006
6 Definitions
The experimental variance s2 (K (q , (pulses/ m3)2,
vi
j )
)
Equations of K-factor, mean, repeatability and
of K
reproducibility.
vi(qj) from repeated measurements at flow rate
q
j:
The K factor is the number of pulses per unit
2
n
1
⎛
⎞
volume. Repeatability and reproducibility are defined
2
s (K (q ))=
K (q )−K (q ) ;
n= 5 (4)
vi
j
Σ vi j
vj
j
n 1
⎜
⎜
⎟
⎟
−
here in accordance with International Vocabulary of
i 1
= ⎝
⎠
basic and General Terms in Metrology published by
The K-factor global mean value K , pulses/ m3, for
ISO 1995.
K-factor arithmetic mean from the participating
The repeatability is expressed in terms of the
laboratories:
dispersion characteristics of the results without
changing any parameter during the measurement.
1 p
The term reproducibility refers to planned changes
K =
K (q );
Σ
p = 4
(5)
p
vj
j
like time, position of the meters, and installation
j 1
=
effects. The reproducibility is expressed in terms of
the dispersion characteristics of the results. The
where p is the number of the mean K-factors in each
figures presented in this report are based on the
laboratory and for each flow rate.
__
following definitions:
2
Laboratory reproducibility s (K vj (q )
) , pulses/ m3, at
j
The common way to present the data of turbine
the same flow rate and the same configuration:
meters is the K-factor as a function of volumetric
2
⎛
⎞
__
p
__
__
flow rate or Reynolds number.
2 ⎛
⎞
1
⎜
⎟
s ⎜K
;
vj (q )⎟ =
K vj (q ) − K
j
Σ
j
⎝
⎠ p −1 j 1= ⎜⎜
⎟
⎟
⎝
⎠
The K-factor, Kvi(qj), pulses/m3, for a single
measurement i at the flow rate qj:
p
= 4 (PTB) and p = 8 (CENAM)
(6)
counted pulses
from meter
K (q ) =
(1) Relative error e, %, between KPTB from PTB and
vi
j
volume
KCENAM factor from CENAM is defined by:
All of the K-factors, which were produced in CENAM
__
⎛⎡
⎤
⎞
⎜ K
⎟
facility, were referenced to the standard temperature
e
PTB
= ⎢
⎥ −1 ⋅100
⎜
(7)
__
⎟
⎢
⎥
selected to be 20 °C, using:
⎜ K
⎟
⎝⎣ CENAM ⎦
⎠
K = K 1 + 3α T − T
(2)
The deviation En normalized [3] in relation to the
0
(
(
0 )
stated uncertainty is defined by:
where,
K0 is the meter K-factor in pulses per cubic meter at
K CENAM K
-
PTB
the reference temperature, T
E =
(8)
0.
n
2
2
K
(U
+U
CENAM
PTB )
is the meter K-factor in pulses per cubic meter at
the flowing temperature, T.
α is the linear expansion coefficient for the meter
where K CENAM is the measurement result from CENAM
material in °C-1.
as given in its information, K PTB is the reference value.
UCENAM is the expanded uncertainty of K CENAM and
In the case of the PTB facility, the temperature is
UPTB is the expanded uncertainty of K PTB in
kept around 20 °C during the test.
accordance to EAL-P7, Interlaboratory comparisons [3].
The K-factor arithmetic mean value K (q ),
The reference values are provided by mean values
vj
j
between PTB and CENAM results, with exception of
pulses/m3, for a series at flow rate j:
the En deviation where the reference values are
1 n
K (q ) =
K (q ) ;
n = 5
(3)
provided by PTB.
vj
j
Σ
n
vi
j
i =1
where n is the number of measurements at qj flow
rate.
4
6th ISFFM
May 16-18, 2006
7 Data
and
Results
for MTR1 in downstream position were due to an
anomalous condition of MTR 2 after the initial test at
Now, it should be take into account the CENAM.
measurements values of MTR 1; because the
malfunction of MTR 2, during the comparison tests.
The results shown in figure 4 indicated that, in
Also, we found a large variance in the K-factor within
configuration 2, up stream position (MTR 1) at lower
different tests, raising the possibility that the meter
flow, the spread is about 0,05 %. It also noted in
was altered in some significant way, not letting the
figure 5 no significant differences through the flow
rotor spin freely and subsequently damaging the
range occurred.
bearings.
Table 10 and figure 5 show the deviation En
This report shows the data summary and test results
normalized with respect to the stated uncertainty.
for MTR 1.
Also, it is concluded from results shown in table 10
that for high and mid-flow rate between final test at
The mean values from the data summary and
CENAM and test at PTB no significant differences
results from the tests are shown in tables 4 through
occurs.
10, and plots of such values are shown in figures 3,
4 and 5. The figures and tables also indicate that the
The results shown in table 10 and figure 5 indicate
mean K-factors were referenced to the standard
that, in arrangement 1 at the mid-flow rate and high
temperature, 20 °C.
flow rate, the downstream meter (MTR 1) has a
higher error between PTB mean value and CENAM
For the results graphed in figures 3 and 4 the mean
mean value, e = 0,09 % and e = 0,08 % . Table 10,
K-factor values, standard deviations, reproducibility
also shows those deviations En in these results for
and expanded uncertainty of these means K-factor
MTR 1 are 1,54 in mid-flow and 1,43 in high flow.
values are given in tables 4-9.
It is noted that for the MTR 1 (figure 5) the absolute
The results plotted in figure 5 shows that the total
values of the deviation E
spread in these results for MTR 1 in configuration 1
n for final test are less than
the unit except for initial test at CENAM for MTR 1 at
(downstream position) is about 0,12 % from highest
mid-flow rate and high flow rate in configuration 1.
to lowest values.
The criterion of E
n requests the absolute values of En
were be less than unity in order to get acceptable
It is concluded from these results that the significant
measurements.
differences between initial and final tests at CENAM
Table 4. Data summary from CENAM facility (The tests 1A, 1B, 2G and 2H were run in configuration 1).
Summary of initial test mean values at CENAM
Volumetric
Volume
Mean
Relative
Relative
Uncertainty
Configuration
flow rate
V
Pulses
K-factor
standard
reproducibility
of
MTR 1
qv
(m3)
@ 20 °C
deviation
K factor
(m3/h)
(pulses/m3)
s
U (%)
Down stream position test A and B
249,4
9,992 4
65 450,2 6
551,6 1,26·10-5
3,78·10-4 ±
0,048
150,1
10,014 7
65 663,2 6
558,3 2,45·10-5 3,65·10-4 ±
0,048
49,8
1,496 9
9 831,6 6
569,4 8,47·10-5 5,04·10-4 ±
0,054
49,6
1,491 2
9 793,4 6
569,1 5,44·10-5 5,04·10-4 ±
0,054
149,5
9,972 6
65 385,2 6
558,1 5,60·10-5 3,65·10-4 ±
0,048
248,9
9,972 0
65 316,2 6
551,6 8,11·10-6 3,78·10-4 ±
0,048
1
Down stream position test G and H
49,9
1,499 2
9 846,4 6
569,1 6,37·10-5 5,04·10-4 ±
0,054
150,0
10,005 2
65 605,2 6
558,6 1,53·10-5 3,65·10-4 ±
0,048
249,3
9,985 1
65 404,4 6
551,7 1,24·10-5 3,78·10-4 ±
0,048
249,3
9,988 7
65 424,2 6
551,4 2,02·10-5 3,78·10-4 ±
0,048
150,0
10,010 2
65 631,0 6
558,1 1,67·10-5 3,65·10-4 ±
0,048
49,9
1,498 6
9 841,6 6
568,8 8,48·10-5 5,04·10-4 ±
0,054
5
6th ISFFM
May 16-18, 2006
The table above lists the mean values of K-factors and the standard deviations calculated from 5 values, the
reproducibility for each flow rate from 8 mean values and the K-factor expanded uncertainty.
Table 5. Data summary from PTB facility (The tests 1A, 1B, 2G and 2H were run in configuration 1).
Summary of mean values at PTB
Volumetric
Volume
Mean K-
Relative
Uncertainty
Configuration
flow rate
V
Pulses
factor
standard
Relative
of
MTR 1
qv
(m3)
@ 20 °C
deviation
reproducibility
K factor
(m3/h)
(pulses/m3)
s
U (%)
Down stream position test A and B
50,3
2,769 2
18 178,0 6
564,3 3,11·10-5 1,23·10-4 ±
0,032
151,6
2,789 9
18 291,4 6
556,3 3,83·10-5 3,81·10-5 ±
0,030
251,7
2,785 0
18 237,0 6
548,2 2,44·10-5 1,92·10-5 ±
0,030
251,7
2,783 7
18 227,6 6
548,0 4,20·10-5 1,92·10-5 ±
0,030
151,2
2,781 9
18 237,4 6
555,8 1,60·10-4 3,81·10-5 ±
0,030
50,3
2,768 8
18 171,2 6
562,8 1,28·10-4 1,23·10-4 ±
0,032
1
Down stream position test G and H
50,4
2,776 1
18 242,4 6
571,3 7,78·10-5 1,16·10-4 ±
0,032
150,7
2,771 4
18 192,4 6
564,3 3,65·10-5 5,12·10-5 ±
0,030
251,8
2,785 7
18 264,6 6
556,6 1,40·10-4 3,94·10-5 ±
0,030
251,5
2,782 8
18 247,4 6
557,2 3,69·10-5 3,94·10-5 ±
0,030
151,0
2,775 6
18 219,8 6
564,2 2,87·10-4 5,12·10-5 ±
0,030
48,8
2,685 8
17 645,8 6
570,1 6,93·10-5 1,16·10-4 ±
0,032
The table lists the mean values of K-factors and standard deviations calculated from 5 values, the
reproducibility for each flow rate from 4 mean values and the K-factor expanded uncertainty.
Table 6. Data summary from CENAM facility (The tests 1A, 1B, 2G and 2H were run in configuration 1).
Summary of final test mean values at CENAM
Volumetric
Volume
Mean K-
Relative
Uncertainty
flow rate
V
Pulses
factor
standard
Relative
of
Configuration
qv
(m3)
@ 20 °C
deviation
reproducibility
K factor
MTR 1
(m3/h)
(pulses/m3)
s
U (%)
Down stream position test A and B
249,7
9,973 5
65 395,8 6
557,8 2,16·10-5 3,78·10-4 ±
0,048
149,6
9,982 2
65 518,6 6
564,3 1,26·10-5 3,65·10-4 ±
0,048
49,7
1,494 4
9 826,8 6
576,5 1,44·10-5 5,04·10-4 ±
0,054
49,8
1,497 3
9 844,8 6
576,0 2,45·10-5 5,04·10-4 ±
0,054
150,3
10,030 8
65 818,4 6
562,4 8,72·10-5 3,65·10-4 ±
0,048
249,3
9,967 2
65 342,0 6
556,5 8,47·10-5 3,78·10-4 ±
0,048
1
Down stream position test G and H
49,9
1,498 9
9 852,6 6
574,2 2,16·10-5 5,04·10-4 ±
0,054
149,5
9,976 6
65 456,6 6
561,8 1,26·10-5 3,65·10-4 ±
0,048
249,6
9,979 6
65 388,6 6
553,1 1,44·10-5 3,78·10-4 ±
0,048
249,5
9,976 8
65 365,4 6
552,6 2,45·10-5 3,78·10-4 ±
0,048
149,8
9,995 9
65 571,0 6
560,7 8,72·10-5 3,65·10-4 ±
0,048
49,8
1,494 7
9 818,8 6
570,2 8,47·10-5 5,04·10-4 ±
0,054
The table lists the mean values of K-factors and standard deviations calculated from 5 values, the
reproducibility for each flow rate from 4 mean values and the K-factor expanded uncertainty.
6
6th ISFFM
May 16-18, 2006
Kv factor @ 20 °C - volumetric flowrate
Configuration 1, MTR 1 (Brooks)
CENAM 08-11-2004 Test 1A (high-low)
CENAM 08-11-2004 Test 1B (low-high)
6580.0
CENAM 11-11-2004 Test 1G (low-high)
CENAM 11-11-2004 Test 1H (high-low)
PTB 22-11-2004 Test 1A
6575.0
PTB 22-11-2004 Test 1B
)
0,12 %
PTB 25-11-2004 Test 1G
3 m 6570.0
PTB 25-11-1004 Test 1H
s/
CENAM 02-12-2004 Test 1A
l
se
u
CENAM 02-12-2004 Test 1B
6565.0
CENAM 06-12-2004 Test 1G
r
(
p
o
CENAM 06-12-2004 Test 1H
ct
a
6560.0
f
v
0,1 %
K
± 0,04 %
6555.0
0,1 %
6550.0
6545.0
0
50
100
150
200
250
300
qv (m3/h)
Figure 3. The mean K factor results for down stream position of MTR 1.
(The space between arrows represents spread of data).
Table 7. Data summary from CENAM facility (The tests 1C, 1D, 2E and 2F were run in configuration 2).
Summary of initial test mean values at CENAM
Volumetric
Volume
Mean K-
Relative
Uncertainty
flow rate
V
Pulses
factor
standard
Relative
of
Configuration
qv
(m3)
@ 20 °C
deviation
reproducibility
K factor
MTR 1
(m3/h)
(pulses/m3)
s
U (%)
Up position test C and D
49,9
1,499 4
9 842,3 6
565,5 1,46·10-4 6,96·10-5 ±
0,040
149,4
9,967 7
65 345,2 6
557,0 1,38·10-5 5,37·10-5 ±
0,040
249,3
9,987 3
65 410,0 6
550,6 2,07·10-5 1,09·10-4 ±
0,041
249,2
9,984 3
65 389,2 6
550,6 2,14·10-5 1,09·10-4 ±
0,041
149,8
9,992 9
65 508,2 6
556,9 1,63·10-5 5,37·10-5 ±
0,040
49,8
1,494 5
9 809,6 6
565,3 8,07·10-5 6,96·10-5 ±
0,040
2
Up stream position test E and F
249,4
9,988 8
65 415,4 6
550,3 3,68·10-5 1,09·10-4 ±
0,041
149,6
9,979 8
65 417,4 6
556,4 3,15·10-5 5,37·10-5 ±
0,040
49,8
1,496 9
9 826,4 6
565,9 6,63·10-5 6,96·10-5 ±
0,040
49,8
1,495 9
9 817,8 6
564,6 6,47·10-5 6,96·10-5 ±
0,040
149,8
9,994 7
65 512,0 6
556,1 1,63·10-5 5,37·10-5 ±
0,040
249,4
9,988 5
65 400,0 6
549,1 1,77·10-5 1,09·10-4 ±
0,041
The table lists the mean values of K-factors and standard deviations calculated from 5 values, the
reproducibility for each flow rate from 8 mean values and the K-factor expanded uncertainty.
7
6th ISFFM
May 16-18, 2006
Table 8. Data summary from PTB facility (The tests 1C, 1D, 2E and 2F were run in configuration 2).
Summary of mean values at PTB
Volumetric
Volume
Mean K-
Relative
Uncertainty
flow rate
V
Pulses
factor
standard
Relative
of
Configuration
qv
(m3)
@ 20 °C
deviation
reproducibility
K factor
MTR 1
(m3/h)
(pulses/m3)
s
U (%)
Up stream position test C and D
50,3
2,769 2
18 178,0 6564,3 3,11·10-5 1,23·10-4 ±
0,032
151,6
2,789 9
18 291,4 6556,3 3,83·10-5 3,81·10-5 ±
0,030
251,7
2,785 0
18 237,0 6548,2 2,44·10-5 1,92·10-5 ±
0,030
251,7
2,783 7
18 227,6 6548,0 4,20·10-5 1,92·10-5 ±
0,030
151,2
2,781 9
18 237,4 6555,8 1,60·10-4 3,81·10-5 ±
0,030
50,3
2,768 8
18 171,2 6562,8 1,28·10-4 1,23·10-4 ±
0,032
2
Up stream position test E and F
252,1
2,790 6
18 272,4 6
547,9 1,94·10-5 1,92·10-5 ±
0,030
151,7
2,790 5
18 295,0 6
556,3 2,80·10-5 3,81·10-5 ±
0,030
50,1
2,759 4
18 108,8 6
562,7 3,47·10-5 1,23·10-4 ±
0,032
50,1
2,756 6
18 090,8 6
562,6 4,35·10-5 1,23·10-4 ±
0,032
152,4
2,805 1
18 391,0 6
556,3 3,08·10-5 3,81·10-5 ±
0,030
251,9
2,787 7
18 253,8 6
548,0 3,10·10-5 1,92·10-5 ±
0,030
The table lists the mean values of K-factors and standard deviations calculated from 5 values, the
reproducibility for each flow rate from 4 mean values and the K-factor expanded uncertainty.
Table 9. Data summary from CENAM facility (The tests 1C, 1D, 2E and 2F were run in configuration 2).
Summary of final test mean values at CENAM
Volumetric
Volume
Mean K-
Relative
Uncertainty
flow rate
V
Pulses
factor
standard
Relative
of
Configuration
qv
(m3)
@ 20 °C
deviation
reproducibility
K factor
MTR 1
(m3/h)
(pulses/m3)
s
U (%)
Up stream position test C and D
49,7
1,494 2
9 808,6 6
565,5 8,62·10-5 6,96·10-5 ±
0,041
149,6
9,980 8
65 436,8 6
557,2 1,46·10-4 5,37·10-5 ±
0,040
249,5
9,966 6
65 266,8 6
549,5 5,03·10-5 1,09·10-4 ±
0,041
249,6
9,966 9
65 265,6 6
549,2 1,38·10-5 1,09·10-4 ±
0,041
150,3
10,025 5
65 726,0 6
556,8 1,16·10-5 5,37·10-5 ±
0,040
50,0
1,500 8
9 850,8 6
564,8 2,07·10-5 6,96·10-5 ±
0,041
2
Up stream position test E and F
249,6
9,969 3
65 279,8 6
549,0 8,62·10-5 1,09·10-4 ±
0,041
149,6
9,979 4
65 422,4 6
556,7 1,46·10-4 5,37·10-5 ±
0,040
49,9
1,498 1
9 834,6 6
565,6 5,03·10-5 6,96·10-5 ±
0,041
50,0
1,501 4
9 856,4 6
565,8 1,38·10-5 6,96·10-5 ±
0,041
149,8
9,995 7
65 526,0 6
556,4 1,16·10-5 5,37·10-5 ±
0,040
249,6
9,987 0
65 396,0 6
549,1 2,07·10-5 1,09·10-4 ±
0,041
The table lists the mean values of K-factor and standard deviation calculated from 5 values, the
reproducibility for each flow rate from 8 mean values and the K-factor expanded uncertainty.
8
6th ISFFM
May 16-18, 2006
Kv factor @ 20 °C - volumetric flowrate
Configuration 2, MTR 1 (Brooks) up stream position
6570.0
CENAM 09-11-2004 Test 2C (low -high)
CENAM 09-11-2004 Test 2D (high-low )
CENAM 10-11-2004 test 2E (high-low )
CENAM10-11-2004 Test 2F (low -high)
PTB 23-11-2004 Test 2C
PTB 23-11-2004 Test 2D
6565.0
0,05 %
PTB 24-11-2004 Test 2E
PTB 24-11-2004
)3
CENAM 02-12-2004 Test 2C
CENAM 03-12-2004 Test 2E
/
m
6560.0
CENAM 02-12-2004 Test 2D
CENAM 2004-12-03 TEST 2F
l
ses
u
r
(
p
o
act 6555.0
0,02 %
f
v
K
± 0,04 %
6550.0
0,04 %
6545.0
0
50
100
150
200
250
300
qv (m3/h)
Figure 4. The K-factor results for up stream position of MTR 1.
(The space between arrows represents spread of data.)
Table 10. Normalized deviation En in relation to the uncertainty and relative errors for MTR 1in configuration
1 and configuration 2.
Summary Results
The reference values were provided by PTB
MTR 1 Down stream
MTR 1 Up stream
High flow 250 (m3/h)
CENAM PTB CENAM
CENAM PTB CENAM
Mean K- factor @
6 551,6
6 555,0
6 550,2
6 549,2
20 °C (pulses/m3)
Deviation (%) [PTB /
6 556,9
6 548,0
0,08
0,03
- 0,03
- 0,02
CENAM]
En number
1,43
0,07
- 0,65
- 0,35
MTR 1 Down stream
MTR 1 Up stream
Half flow 150 (m3/h)
CENAM PTB CENAM
CENAM PTB CENAM
Mean K factor @
6 558,3
6 562,3
6 556,6
6 556,8
20 °C (pulses/m3)
Deviation (%) [PTB /
6 564,0
6 556,2
0,09
0,03
- 0,01
- 0,01
CENAM]
En number
1,54
0,44
- 0,14
- 0,18
MTR 1 Down stream
MTR 1 Up stream
Low flow 50 (m3/h)
CENAM PTB CENAM
CENAM PTB CENAM
Mean K factor @
6 569,1
6 574,2
6 565,3
6 565,4
20 °C (pulses/m3)
Deviation (%) [PTB /
6571,2
6 563,1
0,03
- 0,05
- 0,03
- 0,04
CENAM]
En number
0,52
- 0,74
- 0,67
- 0,72
9
6th ISFFM
May 16-18, 2006
En numbe r v e rsus flowrate
2.00
1.50
1.00
0.50
0.00
En -0.50
-1.00
-1.50
-2.00
0
50
100
150
200
250
300
qv (m3/h)
Initial test at CENAM MTR1 Configuration 2
Final test at CENAM MTR 1 Configuration 2
Initial test at CENAM MTR1 Configuration 1
Final test at CENAM MTR 1 Configuration 1
PTB reference data
Figure 5. The deviation En.
8 Conclusion
6.
Finally, future efforts in the flow
measurement assurance program between
1.
MTR 2 (XO turbine meter) has become
CENAM and PTB include a comparison
altered in some significant manner, in this
test using 200 mm turbine meters. This
case the rotor did not spin freely, and the
second comparison using larger meters
bearings had become damaged.
will be done in 2007.
2.
The result shown that the comparison test
using MTR 1 in configuration 2 – up
Acknowledgements
stream position - has been successfully
carried out with a maximum spread of 0,05
The authors gratefully acknowledge the efforts and
% and En numbers in all cases less that
hard work of his colleagues: Axel Eggestein from
unity.
PTB, José Lara Manríquez and Emmanuel Ríos
3.
The results shown significant differences in
Carrizales from CENAM for collaborating during
the results MTR 1 in configuration 1 –
the comparison test.
down stream position - between PTB and
CENAM. The possible cause for those
References
significant differences can be the influence
of MTR 2 on fluid flow velocity profile. The
total spread in these results for MTR 1 in
[1] Mattingly G. E., Fluid Mechanics Measurements
configuration 1 is about 0,12 %.
Chapter Six, Edited by Richard J. Goldstein,
4.
However, in general, the comparison test
1983
shows that the measurements between
[2] Pöschel W., Engel R., The Concept of a New
PTB and CENAM for MTR 1 are
Primary Standard for Liquid Flow
acceptable. As a result, it is concluded
Measurement at PTB Braunschweig, 9th
that the MTR 1 values for that
FLOMEKO, pp. 7-12, Lund, Sweden, 1998
configuration obtained at CENAM is
[3] EAL European Cooperation for Accreditation of
equivalent to PTB values.
Laboratories,
EAL Interlaboratory
Comparisons EAL-P7, 1st edition, 1996
5.
The comparison was produce valuable
information to improve calibration work for
the participating laboratories.
10
