Flow-meter calibrations for the ID of the ATLAS Experimentfyzika.fs.cvut.cz/research/documents/2009_MD_RM_MV_SM_VV.pdf · Supervisors: Stephen McMahon and Vaclav Vacek Collaborators:

CTU IN PRAGUE ATLAS SCT

Flow-meter calibrations for the ID

of the ATLAS Experiment

Supervisors: Stephen McMahon and Vaclav Vacek Collaborators: R. Marek, M. Doubek and M. Vítek

31.10.2009

Flow-meter calibrations for the ID of the ATLAS Experiment

Supervisors: Stephen McMahon and Vaclav Vacek Collaborators: M. Doubek, R. Marek and M. Vitek Page 2

Abstract This report presents results obtained during measurement of detailed characteristics of the

thermal mass flow-meter Bronkhorst. The initial impulse for this measurement came from the ID

community of ATLAS experiment as a preparatory work for the thermal characteristic

measurement of the detector components where the Bronkhorst thermal mass flow-meter is

employed for the C3F8 vapor mass flow determination. The calibration took place at Prévessin

(H8) where the C3F8 experimental cooling circuit has been built by the department of Physics

from the Czech Technical University in Prague. Within the scope of this measurement several

other flow-meters were either calibrated or used as the reference and some of them will be used

in other projects at CERN.



Content Abstract ........................................................................................................................................... 2

Introduction ..................................................................................................................................... 4 Referential flow-meter .................................................................................................................... 4 Investigated and calibrated flow-meters ......................................................................................... 5 Calibration setup ............................................................................................................................. 6 Calibration of the Bronkhorst thermal mass flow-meter ................................................................ 7

Summary ....................................................................................................................................... 11 List of stable conditions for Bronkhorst thermal mass flow-meter .............................................. 12 Calibration sheet for Bronkhorst flow-meter ................................................................................ 14



Introduction

Calibration of vapor flow-meters inside the two-phase cooling circuit has many advantages.

The most important one is the possibility to use a referential flow-meter for liquid phase which is

generally more precise than vapor flow-meters. The cooling circuit has been prepared by the

Department of Physics from the Czech Technical University in Prague and modified for the

purpose of flow-meter calibration with mass flow capacity currently standing at 5 g/s of C3F8

vapor.

The flow-meter calibration is a rather time consuming procedure due to the necessity to

achieve steady and balanced flow pattern. This fact enforced us to combine several other flow-

meters to use the set-up and time efficiently.

The cooling circuit is equipped with ELMB-based DAQ system using PVSS software. The

calibration of the DAQ system has been checked with Keithley precision multimeter.

Figure 1: Cooling circuit located in Bldg. 887 H8 in Prévessin

Referential flow-meter

All calibrations have been conducted and compared with CORI-flow

type mass flow-meter by Bronkhorst. Its main advantages are high

accuracy, fast response time and mainly the direct mass flow

measurement. The mass flow is calculated from the phase shifting of

two conversely vibrating tube loops. The phase shift is increasing with

higher mass flow. The calibration fit is provided by the manufacturer.

Specification:

Mass flow range: 0…92 ln/min; (0…13.9 g/s)

Temperature range: 0…70 °C

Analog output: 0…5 V

Supply voltage: +15…24 V

A vapor phase volume flow-meter by Schlumberger served as the

second verification of the mass flow. The flow-meter is located at compressor suction line and is

coupled with pressure and temperature sensors for the adequate mass flow calculation.

Figure 2: CORI-Flow

mass flow-meter

IST thermal mass flow sensors

on vapor line

Bronkhorst flow-meter

Compressor station IST reading electronics Distribution manifold



Investigated and calibrated flow-meters The EL-FLOW type sensor by Bronkhorst is a

thermal mass flow-meter specially designed for

mass flow measurement of C3F8 vapor. High

precision, pressure and temperature independency

plus a short reaction time belong to its main

advantages.

Specification:

Mass flow range: 0…100 Nl/min; (0…15 g/s)

Analog output: 0…5 V

Supply voltage: +15…24 V

Figure 3: Bronkhorst thermal mass flow meter

Sensor FS5L (liquid type) by Innovative Sensor

Technology (IST) is fixed in a brass thick-walled

tube (Figure 4.) coupled with special readout

electronics supplied by the IST. It is a very

promising and cheap thermal flow-meter. It

determines mass flow by measuring the resistance of

a RTD (temperature variable resistor) element

heated by an electrical current. An additional

temperature sensor is present on the chip for

compensating the temperature of the liquid.

Figure 4: IST FS5L

Swissflow SF800 turbine volume flow-meters use

an IR sensor to measure revolutions of a

lightweight turbine subjected to liquid flow. Its

output signal is of a rectangular shape. We have

coupled all three of them with

frequency/voltage transducers and calibrated them

in conjunction.

Figure 5: Swissflow SF800 flow meters with two types

of frequency transducers

Sensors IST FS5 for vapor are basically of the

same principle as the FS5L type. The only

difference is the adjustment of the sensor itself for

the low density vapor flow. The sensor requires also

differently tuned readout electronics.

Figure 6: IST FS5 in a Swagelok Tee



Calibration setup By manipulating the temperature of water circuit supplied by chiller that first cools down the

refrigerant entering the CORI-Flow and warms up vapor in heat exchanger later and thanks to

the power change of the heater located on vapor line, the temperature of the vapor may be easily

changed between 15 to 40 °C.

Simplified schematic of the circuit modification during the calibration runs can be seen on

Figure 7. Except from SF800 sensors all flow-meters were calibrated at the same time.

Swissflow sensors were located on three parallel liquid lines. These have had to be opened one at

a time when calibration run took place.

AC

Condenser

AC

3 separated lines Swissflow

flowmeters

CapillariesWater HEX

Heater

IST 8 mm

IST 8 mm

IST 10 mmTwo-stage

compressor unit

CORI

referential

flowmeter

Vapor Liquid

IST liquid

Bronkhorst

thermal flowmeter

Schlumberger

Figure 7: Simplified cooling circuit scheme with all flow-meters

Readings of the mass flow from the flow-meters CORI-Flow and Schlumberger differ in

almost constant ratio 1:0.874. Schlumberger gives a lower flow rate. Therefore Schlumberger

served as a second reference sensor in cases with high deviation of the measured points from the

final fit. CORI / Schlumberger

y = 0.8743x

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

CORI [g/s]

Sch

lum

berg

er

[g/s

]

Figure 8: Comparison of the mass flow indicated by Schlumberger and CORI



Calibration of the Bronkhorst thermal mass flow-meter

The measurement took place between the 14th

to 18th

of October 2009 with some additional

measurements on the 21st, 22

nd, 23

rd and on the 28

th of October 2009.

Out of thirty thousand collected data points 82 fully stable sections of working points have

been evaluated in order to cover all thinkable dependencies as well as their tendencies. Vibration

from compressor station has been eliminated by the solid anti-vibration insulation of the

referential CORI flow-meter as well as the Bronkhorst thermal flow-meter.

Data have been recorded in maximal possible frequency. Their behavior has been deeply

observed and all intervals of representative stable values have been carefully chosen. Time

required for the stabilization of the flow pattern within the limit spans from several minutes to

half an hour depending on the nature of the changes in mass flow setting. Temperature

instabilities usually consumed the most of time to achieve a steady flow condition.

Figure 9 shows all the measured and evaluated working points of the Bronkhorst flow-meter

with mass flow of up to 5.0 g/s, which is a current limit of the cooling circuit.

Simple characteristics of the Bronkhorst thermal flowmeter

All measured data

dm /dt = 2.9612U [g/s; V]

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Flowmeter signal voltage U [V]

C3F

8 m

assf

low

dm

/dt

[g/s

]

Figure 9: All measured data in a linear characteristic

Other objective of the calibration was to study the temperature dependency of the Bronkhorst

sensor, if any. By exploring the mass flow difference between a temperature independent fit (see

Fig. 9) and evaluated data points, the temperature dependency is evident (see Fig. 10). We

assume that this dependency has a linear tendency in relation to temperature. For a range

between 10 and 35 °C its convexity is barely visible. It is well within the data dispersion. With

increased temperature the real mass flow is lower than what the Bronkhorst sensor indicates.



Massflow difference to previous fit according to temperature

All measured data

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0

Vapor temperature T [°C]

C3F

8 m

as

sfl

ow

err

or

dm

e/d

t [g

/s]

Figure 10: Mass flow difference to simple linear fit.

Figure 11 shows mass flow difference between evaluated data points and the final suggested

fit. The data are classified according to the single property (vapor pressure, supply voltage, etc.)

by which they differ from our nominal working parameters – low vapor pressure and 16.2 V of

supply voltage.

Working points with higher than nominal vapor pressure are presented also on Fig. 12. It is

safe to say that there is no visible dependency on vapor pressure in the range of (1…2.5) bara for

the measured mass flow interval of (0…5) g/s.

Figure 13 presents mass flow error reflecting temperature of the liquid at the referential CORI

flow-meter. All data points are within the data dispersion except several data points at low

temperature. We have no satisfactory explanation for the sudden decrease of the signal.

Exceeding the dew point temperature might have something to do with it. However no further

investigation of this phenomenon has been conducted. Those points have been excluded from

calculation of the final fit.

Supply voltage dependency has not been proven. The results may indicate a very slight rising

tendency but within the data dispersion (see Fig. 14). Only four working points with elevated

supply voltage have been measured. For the best results the use of 16 V supply voltage is

recommended.

These values have been omitted from

the final calculation (vide infra).



Massflow difference to the final fit for classified data

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Flowmeter signal voltage U [V]

C3F

8 m

as

sfl

ow

dm

/dt [

g/s

]

Nominal High vapor pressure High supply voltage Cold liquid at CORI

Fig.ure 11: Difference of mass flow to the final fit

Massflow difference to the final fit according to vapor pressure

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6

Vapor pressure p [bara]

C3F

8 m

as

sfl

ow

dm

/dt [

g/s

]

Fig.ure 12: Mass flow difference to the final fit according to vapor pressure

These working points have been

excluded from the calculation.





Massflow difference to the final fit according to liquid temperature

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0

Liquid temperatore T [°C]

C3F

8 m

as

sfl

ow

dm

/dt [

g/s

]

Figure 13: Mass flow difference to the final fit according to liquid temperature at CORI referential flow-

meter

Massflow difference to the final fit according to supply voltage

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0

Flowmeter supply voltage U [V]

C3F

8 m

as

sfl

ow

dm

/dt [

g/s

]

Fig.ure 14: Mass flow difference to the final fit according to supply voltage







Calibration of Swissflow SF800 liquid flow-meters coupled with frequency

transducers

Swissflow calibration

dm /dt = 1.6113U + 0.5512 [g/s; V]

dm /dt = 1.6811U + 0.737 [g/s; V]

dm /dt = 2.0471U + 0.1645 [g/s; V]

1.2

1.25

1.3

1.35

1.4

1.45

1.5

1.55

1.6

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Transducer's signal voltage [V]

Ma

ss

flo

w [

g/s

]

Swissflow 1 Swissflow 2 Swissflow 3

Linear (Swissflow 1) Linear (Swissflow 2) Linear (Swissflow 3)

Figure 15: Swissflow SF800 calibration fits

Summary

The Bronkhorst thermal flow-meter behaved as expected. The temperature dependency causes

rising of the output signal by 0.34% per 1 °C in increased temperature. For mass flow of 10 g/s

and maximally expected difference in temperature of 10 °C the temperature dependency might

induce the error up to 0.34 g/s. The calibration fit includes a correction for temperatures different

from 17 °C that has been the most frequent value during experimental runs in the PIT.



List of stable conditions for Bronkhorst thermal mass flow-meter

Time

identification

Referential mass flow-meter Vapor

temperature

Bronkhorst

signal

Difference to

the final fit

Comment

[hh:mm:ss] CORI [g/s] Schlumberger [g/s] [°C] [V] [g/s]

- 0 0 - 0 0 No offset

12:06:00 4.01 3.49 19.1 1.332 0.043

12:43:10 4.73 4.13 18.8 1.577 0.034

13:09:18 4.49 3.93 19.0 1.499 0.033

13:39:20 4.38 3.84 19.1 1.462 0.035

14:03:03 3.81 3.3 19.4 1.269 0.037

14:19:23 3.70 3.24 19.5 1.232 0.039

14:42:20 2.40 2.13 20.0 0.798 0.035

15:03:52 2.57 2.27 20.1 0.854 0.038

15:25:05 2.96 2.6 20.0 0.985 0.040

16:00:07 1.68 1.5 20.5 0.559 0.030

16:18:57 1.52 1.36 20.5 0.503 0.030

16:37:52 1.43 1.27 20.6 0.473 0.029

16:59:10 1.28 1.13 20.6 0.424 0.029 2.11 bara

17:23:28 3.73 3.25 19.6 1.240 0.048 2.19 bara

17:38:45 3.99 3.4 19.5 1.328 0.043 2.20 bara

17:59:47 4.39 3.79 19.4 1.462 0.043 2.21 bara

18:37:45 4.46 3.88 18.2 1.483 0.038

18:56:07 4.49 3.92 28.5 1.559 0.005

12:15:35 4.78 4.11 9.9 1.559 -0.006

12:39:20 4.77 4.09 13.9 1.592 -0.051

13:05:00 4.76 4.13 20.4 1.621 -0.046

13:28:08 4.75 4.15 24.3 1.629 -0.013

13:56:00 4.73 4.16 28.9 1.640 0.018

14:06:43 4.73 - 29.4 1.633 0.043 23V supply

14:28:57 4.73 4.11 10.9 1.517 0.090 23V supply

14:52:57 4.85 4.18 12.5 1.598 -0.009

15:12:50 4.80 4.13 14.5 1.598 -0.033

15:28:52 4.78 4.11 16.8 1.608 -0.040

15:45:28 4.83 4.18 22.8 1.656 -0.041

15:59:57 4.86 4.24 22.6 1.656 -0.004

16:25:27 4.96 4.3 12.5 1.618 0.032

16:48:35 4.99 4.34 18.3 1.684 -0.036

17:11:52 4.61 4.01 19.9 1.559 -0.018

17:30:25 4.61 4.01 13.4 1.513 0.020

18:17:25 4.59 - 12.6 1.521 -0.037 2.27 bara

18:47:58 4.60 - 12.3 1.524 -0.041 2.27 bara

19:55:00 4.59 - 19.2 1.552 -0.023 2.27 bara

10:19:05 3.97 3.45 16.1 1.329 -0.021

10:48:37 4.39 3.83 15.8 1.469 -0.033



11:14:55 4.37 3.84 23.2 1.511 -0.060

11:36:55 4.00 3.46 16.2 1.330 0.003

11:53:25 3.98 3.44 20.8 1.360 -0.038

12:10:15 3.97 3.46 28.3 1.392 -0.040

12:26:52 3.67 3.22 24.8 1.255 0.013

12:43:20 3.69 3.23 16.8 1.216 0.041

13:04:28 2.37 2.13 18.1 0.798 -0.007

13:27:47 2.35 2.11 24.5 0.814 -0.023

13:45:10 2.34 2.11 34.0 0.841 -0.030

13:56:17 2.80 2.5 32.9 0.990 -0.003

14:14:53 2.81 2.5 21.4 0.941 0.033

14:33:02 2.81 2.5 18.0 0.935 0.016

14:51:57 2.35 2.1 18.5 0.790 0.000 1.62 bara

15:12:45 2.32 2.07 18.6 0.780 -0.003 2.52 bara

15:36:30 2.33 2.08 18.6 0.786 -0.016 1.85 bara

15:52:22 1.02 0.87 19.8 0.348 -0.015

16:19:05 1.16 1.04 25.1 0.406 -0.023

16:42:10 1.14 1.04 20.4 0.392 -0.020

14:43:20 4.47 3.93 15.2 1.498 -0.043

15:53:10 4.42 3.88 18.6 1.463 0.059

16:06:02 4.42 3.88 18.3 1.467 0.045 23V supply

16:17:57 4.41 3.88 18.2 1.471 0.024

16:44:07 4.49 3.97 23.2 1.529 0.000

17:03:22 4.46 - 21.8 1.504 0.024

17:23:35 2.86 2.6 23.7 0.991 -0.046 12.3 °C Liq.

17:47:57 2.71 2.62 19.2 0.978 -0.193 11.2 °C Liq.

18:09:02 2.32 2.22 20.2 0.835 -0.153 10.9 °C Liq.

18:20:05 2.35 - 20.2 0.849 -0.169 10.9 °C Liq.

18:36:25 2.44 - 20.0 0.893 -0.211 10.9 °C Liq.

10:06:27 4.13 3.63 15.8 1.380 -0.022 12.8 °C Liq.

10:36:30 5.03 - 32.9 1.782 -0.016

11:54:02 4.90 - 11.3 1.595 0.028

12:33:12 4.78 - 12.1 1.572 -0.010

13:26:58 3.84 - 21.0 1.290 0.023

13:44:47 3.90 - 16.6 1.290 0.028

15:10:00 2.64 2.4 20.3 0.906 -0.041 12.4 °C Liq.

16:00:50 2.78 - 20.1 0.958 -0.056 12.3 °C Liq.

16:28:27 2.85 - 18.9 0.976 -0.058 12.4 °C Liq.

16:48:53 2.85 - 23.3 0.994 -0.068 12.4 °C Liq.

17:21:05 4.56 - 20.4 1.540 0.002

17:40:22 4.15 - 27.3 1.440 -0.015

10:58:23 4.98 4.37 32.0 1.720 0.085

17:19:42 2.78 - 29.4 0.949 0.056 23V supply Table 1: List of stable conditions



Calibration sheet for Bronkhorst flow-meter M. Doubek, R. Marek, M. Vítek and V. Vacek

CTU Prague, 31.10.2009

F-113AC-AAD-99-V pmax = 100 bar

/min 0...100 g/s 15 ... 0 nlm

RS232 + analog (n/c control)

Analog output 0…5 V

Supply voltage +15…24 Vdc

Viton sealed

FC g 05.9C) 0 ;bar (1 l 1for C V; /min;l ; 170676.08693.19

C V; g/s; ; 170102.099695,2

)( ;

83ann

00

TUUm

TUUm

TfaTTkUaUm

Bronkhorst flow meter characteristics

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Signal voltage [V]

Ma

ss

flo

w [

g/s

]

0

10

20

30

40

50

60

70

80

90

100

Ma

ss

flo

w [

l n/m

in]

T = 10 °C T = 15 °C T = 17 °C T = 19 °C T = 25 °C

RS232 wiring used in calibration

1 Not connected

2 Analog output 0…5 V

3 Not connected

4 Ground

5 Not connected

6 Not connected

7 Supply voltage +15…24 Vdc

8 Ground

9 Shield

Bronkhorst thermal flow meter

Extrapolated data Calibration have been

conducted from 0 to 5.0 g/s

Calibration sheet for Bronkhorst flow-meter M. Doubek, R. Marek, M. Vítek and V. Vacek

CTU Prague, 31.10.2009

CTU IN PRAGUE ATLAS SCT

F-113AC-AAD-99-V pmax = 100 bar

/min 0...100 g/s 15 ... 0 nlm

RS232 + analog (n/c control)

Analog output 0…5 V

Supply voltage +15…24 Vdc

Viton sealed

FC g 05.9C) 0 ;bar (1 l 1for C V; /min;l ; 170676.08693.19

C V; g/s; ; 170102.099695,2

)( ;

83ann

00

TUUm

TUUm

TfaTTkUaUm

Bronkhorst flowmeter characteristics

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Signal voltage [V]

Ma

ss

flo

w [

g/s

]

0

10

20

30

40

50

60

70

80

90

100

Ma

ss

flo

w [

l n/m

in]

T = 10 °C T = 15 °C T = 17 °C T = 19 °C T = 25 °C

RS232 wiring used in calibration

1 Not connected

2 Analog output 0…5 V

3 Not connected

4 Ground

5 Not connected

6 Not connected

7 Supply voltage +15…24 Vdc

8 Ground

9 Shield

Bronkhorst thermal flow meter

Calibration have been

conducted from 0 to 5.0 g/s Extrapolated data

Documents

Flow-meter calibrations for the ID of the ATLAS Experimentfyzika.fs.cvut.cz/research/documents/2009_MD_RM_MV_SM_VV.pdf · Supervisors: Stephen McMahon and Vaclav Vacek Collaborators: