PT100 Flow Cell

• Pt100 Flow Cell design

• How it works

• ELMB flow scan system

• Flow Cell calibration

• Tests for stability in gas flow measurements

EP-TA1 Gas

October 2003 Serguei Morozov

Pt100 Flow Cell designEP-TA1 Gas

October 2003 Serguei Morozov

How it worksEP-TA1 Gas

October 2003 Serguei Morozov

~ 30 sec

20°C

ELMB flow scan systemEP-TA1 Gas

October 2003

ELMB128 with theAtmega128L processor

Power supply card and Mother Card

Serguei Morozov

ELMB flow scan systemEP-TA1 Gas

October 2003

ELMB128 specification• 128 Kb of on-chip flash memory, 4 Kb of SRAM, 4 Kb of EEPROM,• Programming via CAN bus (“FLOWsCAN”, Henk Boterenbrood, NIKHEF )• 6 bipolar or unipolar input ranges (25mV - 5V)• 64-channel multiplexer

ELMB128

Twisted pair CAN

bus

Serguei Morozov

Flow Cell calibrationEP-TA1 Gas

October 2003

Calibration curve (ArCO2CF4)

First polynomial fit

Second polynomial fit

Serguei Morozov

Flow Cell calibrationEP-TA1 Gas

October 2003

-10010

2030405060

708090

2400 2900 3400 3900 4400

DataBase

Flow

Slope

Polynom coeff.

(Flow=p0+p1*x+..)

FlowSlope

DataBasefl(1)=p0+p1*x..fl(2)=p0+p1*x..fl(3)=p0+p1*x..

Serguei Morozov

Stability testsEP-TA1 Gas

October 2003

0.6 l/h6 l/h

= 10 %

1.0 l/h70 l/h

1.4 %

Tamb = 0.18 K / ADC count

Slope = 20 mK/sec

Serguei Morozov

Stability testsEP-TA1 Gas

October 2003

y = -0,0068x + 3740,3

3550

3560

3570

3580

3590

3600

3610

3620

20500 21000 21500 22000 22500 23000 23500 24000 24500 25000

Slope

Tamb 5 –7

mK/sec

K

21°C

50 l/h

28°C

55 l/h

Serguei Morozov

Stability testsEP-TA1 Gas

October 2003

The same positions in Manifold The different positions in Manifold

Serguei Morozov

Stability testsEP-TA1 Gas

October 2003

3mm 5mm

3mm: 1 mbar/cell5mm: 0.5 mbar/cell

Serguei Morozov

Pressure drop at 100 l/h :

ConclusionsEP-TA1 Gas

October 2003

• PT100 flow cell has designed (ELMB read-out, mother card)

• Parameter optimization and stability test were performed:

Time to measure 1 pair of cells (input and output): ~ 30 sec

Minimum error: ± 1 l/h

Temperature stability: + 0.7 l/h per °C ( T=20°C 24°C : 50 l/h 53 l/h)

• Gas flow ranges were estimated:

5mm flow cell: 0-30 l/h… 150 l/h and higher..

3mm flow cell: 80 l/h and higher..

Serguei Morozov