SUPPLEMENTAL OXYGEN MANUAL FOR MODELS … · SUPPLEMENTAL OXYGEN MANUAL FOR MODELS 100, 200, 300...

SUPPLEMENTAL OXYGEN

MANUAL FOR MODELS

100, 200, 300 ANALYZERS

Instruments, Inc.California Analytical

1312 West Grove Avenue, Orange, CA 92865 - 714 974-5560 - Fax 714 921-2531 Website: www.gasanalyzers.com

http://www.gasanalyzers.com/

Section 1 Model 100/200/300 Supplement

Preface This instruction manual is supplemental to the Model 100/200/300 Operations and Maintenance Manual for infrared analyzers. It is sent whenever oxygen is one of the measured parameters of the analyzer. The oxygen measurement information is divided into two parts:

Part 1 – Oxygen by chemical fuel cell sensor techniques.

Part 2 – Oxygen by paramagnetic oxygen sensor techniques.

Please refer to the appropriate part of this supplemental manual according to the method of oxygen determination for your particular analyzer. Thank you.

Supplemental Manual Oxygen- V7.1.doc 1-2


Table of Contents

Part 1 – Oxygen by Chemical Fuel Sensor Techniques ...................................................................5 1. FUEL CELL DETECTOR OPTION............................................................................................6

1.1. Description Fuel Cell Detector Option ................................................................................6 1.2. Product Specifications (Galvanic Fuel Cell Detector).........................................................6 1.3. Principle of operation..........................................................................................................7 1.4. Oxygen Fuel Cells ..............................................................................................................7

2. Preparations for Operation ........................................................................................................8 2.1. Power On............................................................................................................................8 2.2. Zero Adjustment .................................................................................................................8 2.3. Span Adjustment ................................................................................................................8 2.4. Start-Up & Routine Maintenance........................................................................................8 2.5. Zero and Span Calibration Frequency................................................................................8

3. ADJUSTMENTS CHECKS AND REPAIRS...............................................................................9 3.1. Electrical Zero Adjustments................................................................................................9 3.2. Electrical Span Adjustments...............................................................................................9 3.3. The Oxygen Sensor..........................................................................................................10

3.3.1. Coarse-Span-Adjustment ..........................................................................................10 3.3.2. Sensor Checks..........................................................................................................10 3.3.3. Sensor Replacement.................................................................................................10

4. Chemical Fuel Cell Sample Flow (Supplemental) ...................................................................11 5. Electrical Drawings ..................................................................................................................12 Part 2 – Oxygen by Paramagnetic Oxygen Sensor Techniques.....................................................16 6. PARAMAGNETIC OXYGEN OPTION.....................................................................................17

6.1. Description........................................................................................................................17 6.2. Product Specifications Paramagnetic Oxygen Detector...................................................17 6.3. Principle of operation........................................................................................................18

7. Preparations for Operation ......................................................................................................20 7.1. Power On..........................................................................................................................20 7.2. Zero Adjustment ...............................................................................................................20 7.3. Span Adjustment ..............................................................................................................20 7.4. Zero and Span Calibration Frequency..............................................................................20

8. Start-Up & Routine Operation..................................................................................................21 8.1. Sampling System..............................................................................................................21 8.2. Cross sensitivity of gases.................................................................................................22

8.2.1. Example 1 .................................................................................................................22 8.2.2. Example 2 .................................................................................................................22

9. Mechanical Zero Adjustment (Not required with some sensor models) ..................................24



Table of Figures

Figure 2-1 AC Power Switch, Connector, and Fuse .........................................................................8 Figure 4-1 Chemical fuel cell sample flow ......................................................................................11 Figure 5-1 100F O2 analyzer wiring diagram ..................................................................................13 Figure 5-2 100F O2 electrical schematic.........................................................................................14 Figure 5-3 100F O2 PCB component locator ..................................................................................15 Figure 6-1 Magnetic Susceptibility of gases ...................................................................................18 Figure 6-2 The Measuring cell in theory .........................................................................................18 Figure 6-3 Principle of operation.....................................................................................................19 Figure 7-1 AC Power Switch, Connector, and Fuse .......................................................................20 Figure 8-1 Paramagnetic Oxygen Sample flow ..............................................................................21 Figure 9-1 Oxygen sensor adjustment............................................................................................24

Tables

Table 8-1 Cross Sensitivity of gases...............................................................................................23



Part 1 – Oxygen by Chemical Fuel Sensor Techniques



1. FUEL CELL DETECTOR OPTION

1.1. Description Fuel Cell Detector Option The fuel cell option utilizes a low cost replaceable fuel cell to determine the percent level of oxygen contained in the sample gas. A fuel cell analyzer features linear output with low noise and excellent repeatability from 0 to 100% O2.

It is available in two versions, one for oxygen levels up to 25 % and the second for oxygen up to 100%.

Warning: This is a general-purpose analyzer, not suitable for hazardous areas. High-pressure oxygen is very dangerous. Virtually any material will burn in it, possibly explosively. It is essential that persons using this analyzer are aware of the dangers of oxygen, and take all appropriate precautions.

1.2. Product Specifications (Galvanic Fuel Cell Detector)

SAMPLE CONTACT MATERIAL: Stainless steel, Teflon* and Tygon**

DISPLAY: 3 ½" digit panel meter

RANGES: Standard fixed ranges, either A or B

OUTPUTS: 0 to 10 VDC and 4 to 20 mA (0 to 20 mA)

A) Range 1: 0 to 5%; Range 2: 0 to 10%; Range 3: 0 to 25%

B) Range 1: 0 to 25%; Range 2: 0 to 40%; Range 3: 0 to 100%

RESPONSE TIME: 90% full scale in 5 seconds

AMBIENT TEMPERATURE: 5 to 45° C

SAMPLE TEMPERATURE: 0 to 50° C

SAMPLE CONDITION: Particles < 1µ, non-corrosive dry gas

FITTINGS: ¼" tube

NOISE: Less than 1% full scale SAMPLE FLOW RATE: 0.5 –2.0 L/Min

LINEARITY: Better than 1% full scale Power Requirements: 115/230 (± 10%) VAC, 50/60 Hz, 70 watts/channel

REPEATABILITY: Better than 1% full scale Relative Humidity: Less than 90% R.H.***

ZERO SPAN DRIFT: Less than 1% full scale in 24 hours

ZERO & SPAN ADJUSTMENT: Ten turn potentiometer

Specifications subject to change without notice *Teflon is a registered trademark of DuPont.

**Tygon is a registered trademark of the Norton Performance Plastics Corporation

***Non-condensing



1.3. Principle of operation The fuel cell option is designed to measure percent levels of oxygen. The analyzer uses a galvanic fuel cell, which is an electrochemical transducer. The fuel cell contains a cathode, anode, and an electrolyte. A permeable membrane holds the electrolyte in the cell. The sample flows over the membrane and oxygen diffuses in to the fuel cell where it reacts with the electrolyte. This reaction produces an electrical current. This current is directly proportional to the concentration of oxygen in the gaseous mixture surrounding the cell. The current output is linear with an absolute zero. The fuel cell produces no current in the absence of oxygen.

1.4. Oxygen Fuel Cells The standard oxygen sensor (type PSR-39-11) has a shelf life of approximately three years. It is designed to measure oxygen in ambient air. The other gases contained in ambient air are low enough concentrations so as not to be a factor of concern. When used for ambient air measurement the manufacturer estimates the life of the sensor to be approximately three years.

If the standard PSR type sensor is used to measure pure oxygen, oxygen in flue gas or oxygen in stack emissions the life of the standard PSR type sensor will be shorter.

One of the most common emission gases is CO2 and is usually found in concentrations of between 4-20 percent by volume. High levels Of CO2 change the pH of the gel and thus shorten the life of the standard PSR type sensor. The life expectancy dramatically shortens from three years to approximately four weeks at CO2 concentrations of 20% volume.

For the reason stated above, sensor type XLT-39-11 was developed. The XLT type sensor has an electrolytic gel that is strongly buffered and highly caustic. A caustic gel is required to combat the effects of high CO2 concentrations. The average life of this type of sensor is approximately eight to ten months at CO2 levels of 20% by volume; however, the caustic nature of the electrolytic gel creates vapors that clog the cell membrane within a very short time if the cell is not put into immediate use. The shelf life of this type of sensor is approximately two weeks if not stored at a cold, constant temperature. A shelf life of 30 days or so can be achieved if the sensor is kept refrigerated.

As previously stated the XLT-39-11 sensor was developed for use in sample gases containing high levels Of CO2 (approximately 20% volume. or greater). It provides a longer life at high CO2 levels, but the linearity of response has been sacrificed. Typical linearity with this type of sensor is within ± 1% Volume O2.

Because of the non-linearity issue, a third type of sensor was developed. Type XLT-39-11-1 provides a signal that is linear to within ± 0.25% volume O2. This sensor has an average life of eight to ten months at medium CO2 levels of 10% by volume. Levels of CO2 at 20% by volume will shorten the life of this sensor to approximately 3-4 months. The shelf life of this sensor is similar to the XLT-39-11.



2. Preparations for Operation Warning: This is a general-purpose analyzer, not suitable for hazardous areas. High-pressure oxygen is very dangerous. Virtually any material will burn in it, possibly explosively. It is essential that any persons using this analyzer are aware of the dangers of oxygen, and take all appropriate precautions.

2.1. Power On Turn ON the power switch located on the rear panel. The digital panel meter should illuminate. Allow the instrument to warm up for approximately 10 minutes. It is preferable, but not essential, that zero gas flow through the instrument during warm-up.

0

I

Figure 2-1 AC Power Switch, Connector, and Fuse

2.2. Zero Adjustment Zero Adjustment: After the 10 minute warm-up period, flow nitrogen or other zero gas through the instrument at a rate of about 1 liter/min. After the reading stabilizes, adjust the zero control on the front panel until the digital meter (or analog output) is exactly at zero. Nitrogen is the preferred zero Gas.

2.3. Span Adjustment Span Adjustment: Flow span gas through the instrument at about 1 liter/min. After the reading stabilizes, adjust the span control on the front panel until the digital meter or analog output is reading the value corresponding to the span gas concentrations.

Note: Span gas concentration should not be less than 80% of the range to be spanned. Note: On the 0-25% range of the analyzer ambient air may be used as span gas. While ambient air is flowing to the analyzer, adjust the span potentiometer to 20.9% O2.

2.4. Start-Up & Routine Maintenance Prepare and check the sample system. Adjust the flow of sample gas to about 1 liter/min. Select an operating range that is suitable for the oxygen concentration of the sample. The instrument should show a meter indication. The analyzer is designed for extended operation and may be left switched ON continuously.

2.5. Zero and Span Calibration Frequency The zero and span levels should be checked and/or calibrated daily or as often as mandated.



3. ADJUSTMENTS CHECKS AND REPAIRS Note: A millivolt generator is required for this procedure.

3.1. Electrical Zero Adjustments a) Disconnect the plug (P3) from J3 on the printed circuit board (PCB). (P3 is on the end of

the cable assembly coming from the oxygen sensor.)

b) Connect a millivolt generator between pin no. 1 (-) and pin no. 2 (+) at J3 on the PCB.

c) Adjust simulator for 000.00 mv ± 0.01 mv input as measured at TP-8 (+) and common (-).

d) Adjust Front panel zero potentiometer for 000.00 mv ± 0.01 mv as measured between TP-9 and common

e) Set front-panel range switch to Range 1.

f) Adjust R8 for 000.00 mv ± 0.01 mv as measured at TP-4.

g) Adjust R12 for 0.000 VDC ± 0.001 VDC as measured between the 0-10 VDC (+) output terminal and common.

h) Adjust R20 for 4 mA ± 0.01 mA across the 4-20 mA output terminals.

i) Verify O2 display reads 000.0 for all ranges.

j) Repeat steps a) through j) until no further adjustment is required.

3.2. Electrical Span Adjustments Note: Electrical zero adjustments must be made before electrical span adjustments. a) Adjust the millivolt generator and the front-panel span-potentiometer (as necessary) for

exactly 50.00 mv as measured between TP-9 and common.

b) Set front-panel range switch to range 1.

c) Set O2 display selector switch (SW2) to percent (%) O2 mode. Display should read 5.0.

d) Adjust R4 for 1.000 VDC ± 0.001 VDC as measured at TP-4.

e) Set range switch to Range 2 and adjust R3 for 0.500 VDC ± 0.001 VDC at TP-4.

f) Set range switch to Range 3 and adjust R32 for 0.200 VDC ± 0.001 VDC at TP-4.

g) Set range selector to range 1 and verify 1.000 VDC ± 0.00 VDC at TP-4.

h) Adjust R33 for 10.00 VDC ± 0.01 VDC as measured across the 0-10 VDC output terminals.

i) Adjust R24 for 20 mA ± 0.01 mA as measured between the 4-20 mA output terminals. at TP-4

j) Repeat steps a) through j) until no further adjustment is required.

Note: the voltages given in steps e) and f) assume the analyzer is configured for the standard ranges of 0-5, 10, and 25% O2. Consult the factory for the correct voltages required for other non-standard range configurations.



3.3. The Oxygen Sensor The output of the oxygen sensor is a DC output of approximately –10 millivolts at 20.9 % O2. As the sensor is used, it gradually becomes consumed and its voltage output slowly diminishes towards 0 millivolts. Periodic zero and span calibration should be preformed to insure accurate oxygen measurement over the sensor’s life span. Whenever the front panel span potentiometer runs out of adjustment capability it will be necessary to perform a coarse-span-adjustment.

3.3.1. Coarse-Span-Adjustment a) Lift the cover from the analyzer by first removing the retaining screws that secure the cover

to the chassis.

b) Adjust the front panel potentiometer to its mid-setting. The span dial should indicate 5.0.

c) Flow N2 into the analyzer at a flow rate of 1 L/MIN (± 0.5). After the reading stabilizes, adjust the front panel zero potentiometer for an indication of 0.0% O2.

d) Flow an oxygen span gas into the analyzer at a flow rate of 1.0 L/MIN (± 0.5).

e) Locate R27 on the printed circuit board and adjust it as required to obtain a digital display that is equivalent to the value of the span gas being used.

3.3.2. Sensor Checks a) Connect a DC voltmeter to TP-8 (+) and TP-2 common.

b) Introduce a span gas of 21%

c) The measured voltage at TP-8 should be between –3 mv and –13 mv.

d) Whenever the measured voltage is less than –3 mv (or whenever the signal stability becomes an issue) the sensor should be replaced.

Note: A new sensor has a specification of –10 mv (± 3 mv) when measuring 21% O2 at sea level. A correction factor (cf) must be applied to this specification whenever the measuring site is at higher elevations.

mercuryofincheshgWherehg

hgpressurebarometricsitecfWherecfmvoutputCorrected

=

=×−=

""30

)(":10

3.3.3. Sensor Replacement a) Refer to section 2.1 of this manual for selection of the proper type of replacement sensor

b) After replacing sensor it will be necessary to perform a coarse-span-adjustment (refer to paragraph 5.3.1).



4. Chemical Fuel Cell Sample Flow (Supplemental)

O2 SENSOR

NDIR SAMPLE CELL(s)

OUT

P1

IN

NV1

MODEL 100FWITH OPTIONAL FLOWMETER & SAMPLE PUMP

Fl1

MF140

SAMPLEINLET

OUT

IN

NV1MF140

SAMPLEINLET

MODEL 100FWITH OPTIONAL FLOWMETER & SAMPLE PUMP

O2 SENSOR

Fl1

4. IN-LINE FILTER (MF1) CUSTOMER SUPPLIED.

3. INLET & OUTLET CONNECTIONS ARE 1/4” OD TUBE.

2. SAMPLE FLOW RATE: 0.5 L/min to 2.0 L/min.

1. SAMPLE PRESSURE: 1-5 PSIG (NOT REQUIRED WITH OPTIONAL SAMPLE PUMP).

UNLESS OTHERWISE SPECIFIED.NOTES:

NDIR SAMPLE CELL(s)

Figure 4-1 Chemical fuel cell sample flow



5. Electrical Drawings Figure 5-1 100F O2 analyzer wiring diagram

Figure 5-2 100F O2 electrical schematic

Figure 5-3 100F O2 PCB component locator



FRO

NT

PAN

ELPA

NE

L M

ETE

RJ1

0P

101 2 3 4 5 6 7 8 9 10

HI

LOG

ND

CO

MH

OLD 10

3

102

101

0V +5V

DE

CIM

ALPO

INT

POW

ER

10 C

ND

CT

RIB

BO

N C

ABLE

RA

NG

E S

WIT

CH

13

57

92

46

810

S4

R1 R

2 R3

RM

T

1211 10 98

7

23 4 5

61

AC

VI WH

BL

GR

GR

RD

RD

ZER

OR

38

YL BR

GYP

21 2 3 4 5 6 7 8

RA

NG

E

J2

20k Ω

RM

T

P4

J4

MET

ER

1 2 3 4 5 6

BR

CW

CC

W S

GY

OR

BL

YL

CW

CC

W

SPA

NR

3710

0k Ω

S

PU

MP

SW

ITC

H (O

PTI

ON

AL)

ZER

O/S

PAN

S5

NC

NC

CC

+

BK

BK

GR

RD

NO

NO

P8

J8 1 2P

UM

P S

WIT

CH

P9

J9

PUM

P L

ED

1 2

P5 J5

P3

BKRD

J3S

EN

SO

R1

2

1 2 3J1P

1

115

VAC

12

3

SE

NS

OR

BK

WH

GR

OXY

GEN

AN

ALY

ZER

PC

B11

0010

J61 2 1 2 3 4

PU

MP

OU

TPU

TS

BK

P7

J7PU

MP

(OPT

ION

AL)

GR

BK

P6

BK

BR

RD

OR

YL GY

BR

RD

GROU

TPU

T C

ON

NEC

TOR

CH

ASSI

S G

ND

GR

GR

0–10

VD

C

4–20

mA

1 2 3 4 5 6 7 8 9 10 11 12R

MT

J10

+ – + – R2

R3

GN

D+1

5VG

ND

REA

R P

AN

ELPO

WE

R E

NTR

Y M

OD

ULE

H G N

FJ

F1 1AS

3

GC

EA

DH

B

Figure 5-1 100F O2 analyzer wiring diagram



2

11 3

F

J1

115V

AC

R1

1 M

EG

HO

TN

EU

TRA

LG

RO

UN

D2

F

J7 21

C28 .01

200V

SH

OW

N IN

115

VAC

PO

SIT

ION

SW

1

1 3 6 4

2 5

J8 1 2

+15V

17

T114

A–1

0–36

43 6

109 12

F

D1

21

4 3

+–

F

C3

.1 C4

.1

C1

330

UF

50V

C2

100

UF

50V

+ +

1 2

C5

.1 C6

.1

TP

3

TP

4

R28

1.5K

R29

1.5K

U1

LM34

0AT–

15T

P1

3 3

V1

V0

G N D G N D

LM12

0T–1

5U

2

V1

V0

CW

R3

20K

R2

162K

CW

R5

91K

R4

20K

F

–15V

+15V

CW

R8

10K

C25

.1R

92K

R30

6.8K

1 6U

6

84

+–2 3

R6

10K

R7

10K

1 2 3

4

R31

30K

K1

+15V

F

C9

.17

OP

07

F+1

5V

+15V

CW

C17

.1

R22

6.81

KR

24 2KD

4LM

336–

5.0

U3

LM78

05C

T

V1

V0

G N DC

7.11

TP2

C8

.12

3

F

–15V

+15V

CW

18K

R11

R12

10K

C26

.1C

W R33

100K

LED

1

LED

2

GR

EE

N

YE

LLO

W

+5V

+15V

–15V 1 2 3 4J5

FO

UTP

UTS

1 6U

7

84

2 3+–

C10

.17

OP

07

F

F

+15V

R10 2K

C11

.1

C12

.1C

11.1

F

–15V

18

6U

82 3

+–

74

OP

07

C13

.1

F

CW

R13 402

R14

499

R15 100

TP5

TP6

FR

218.

2K

12

J5

R20 2K

M E T E R

1 2 3 4 5 6 7 8 9 10

F

R23 3K

F+1

5V+1

5V

F

R17 33

R34

124

C16 .1

+15V

67

8

1

1

2

OU

T

A 1 O U T A 2 O U T

O F A D J

O F A D J

+ V C C – V C CC O M

– IN

GS

EN

1

GS

ET

1

GS

ET

2

GS

EN

2

+ IN

3 4 5 10 11 12

R18 1K 1%

A D JV

OV

I2 C

24 .1

U9

LM31

7T

3

C14 .1

FF

R19

10K

1%

ZER

O/S

PAN

9U

10IN

A10

1C

11.1

1 41 3

F

F

–15V

D5

5.6V

+15V

+5V

F

F

J4

C18

.1

F

1 2 3 4 5 6

CW CT

CC

W

FF

TP

9C

22.1

C23

.01

C21

.1

500K

R27

F

F

7

OP

07

C20

.1

+15V

R26

10K

1 6U

11

84

2 3+–

J3

FC19

.1

–15V

TP8

R25

10K

F

2

DR

OD

RR

DR

1R

TN

IGN

D+1

5VR

OR

1

J9

F

J2R

AN

GE

+15V

R35

1.5K

1 2 3 4 5 6 7 81 2

F

K2

D2

1N40

02

D3

1N40

02

CW

R32

10K

1 24

3

02FS

%02

1 3

TP1

SW

22

120 Ω

Figure 5-2 100F O2 electrical schematic



J111

5

VAC

115 VAC230 VAC

31

5W1

T1

TP2

TP1

TP3

LED

1LE

D2

R28

R1

R29

C8

C7

C6

U3

C24

C14

C10

C25

U9

U7

R33

R30

R9

R6

R25

R26

J3

1 1 6

2

2

J2J5

81

K2

K1

2

SEN

SO

R

J4ZE

RO

/SPA

N

C21

C23

C20

C22

C9

C19

U11

U6

R34

R11

R10

R12

1

4

C26

TP5

TP4

TP6

TP7

TP8

TP9

J6OUTPUTS

R19

R14

R16

R8

R7 R4

R3

R5

R2

D2

D5

D3

R32

R27

R31

OXY

GEN

FU

EL C

ELL

4101

75

RAN

GE

MET

ER

C15

C18

R24

R23

R13

C13

C16

C12

R18

U8

C11

R20

C5

C17

R22

R21

D4

U1

C3

C4

U2

C2

U10

R35

C1

J9J8

J7

2

21

I +

+

21

1

C28

C27

17

39 10 12

4 6

D1

SW2

FS

Figure 5-3 100F O2 PCB component locator



Part 2 – Oxygen by Paramagnetic Oxygen Sensor Techniques



6. PARAMAGNETIC OXYGEN OPTION

6.1. Description The Paramagnetic Oxygen detector is a thermostated device designed primarily for but not necessarily limited to stationary use. It is a ‘19” rack mount analyzer that is also suitable for bench top use. The operation of the analyzer is based upon the principle of the magneto-dynamic oxygen cell, which is the most accurate and reliable cell for determining the oxygen content of a gas mixture from 0-100 volume percent oxygen.

Warning: This is a general-purpose analyzer, not suitable for hazardous areas. High-pressure oxygen is very dangerous. Virtually any material will burn in it, possibly explosively. It is essential that any persons using this analyzer are aware of the dangers of oxygen, and take all appropriate precautions.

6.2. Product Specifications Paramagnetic Oxygen Detector

SAMPLE CONTACT MATERIAL: Platinum. glass, stainless steel and Viton, Teflon* and Tygon**

DISPLAY: 3 ½" digit panel meter

RANGES: Standard fixed ranges, either A or B or C

OUTPUTS: 0 to 10 VDC and 4 to 20 mA (0 to 20 mA)

A) Range 1: 0 to 1%; Range 2: 0 to 15%; Range 3: 0 to 25%

B) Range 1: 0 to 5%; Range 2: 0 to 10%; Range 3: 0 to 25%

C) Range 1: 0 to 25%; Range 2: 0 to 40%; Range 3: 0 to 100%

RESPONSE TIME: 90% full scale in 2 seconds

AMBIENT TEMPERATURE: 5 to 45° C

SAMPLE TEMPERATURE: 0 to 50° C

SAMPLE CONDITION: Particles < 1µ, non-corrosive dry gas

FITTINGS: ¼" tube

NOISE: Less than 1% full scale SAMPLE FLOW RATE: 0.5 –2.0 L/MIN

LINEARITY: Better than 1% full scale Power Requirements: 115/230 (± 10%) VAC, 50/60 Hz, 70 watts/channel

REPEATABILITY: Better than 1% full scale Relative Humidity: Less than 90% R.H.***

ZERO SPAN DRIFT: Less than 1% full scale in 24 hours

ZERO & SPAN ADJUSTMENT: Ten turn potentiometer

Specifications subject to change without notice *Teflon is a registered trademark of DuPont.

**Tygon is a registered trademark of the Norton Performance Plastics Corporation

***Non-condensing



6.3. Principle of operation The paramagnetic susceptibility of oxygen is significantly greater than that of other common gases, and consequently, the molecules of oxygen are attracted much more strongly by a magnetic field than the molecules of the other gases. Most of the other gases are slightly diamagnetic which means that their molecules are then repelled by a magnetic field.

Figure 6-1 Magnetic Susceptibility of gases

The principle of the magneto-dynamic cell is based upon Faraday's method of determining the magnetic susceptibility of a gas. The cell consists of two nitrogen-filled quarts spheres arranged in the form of a dumbbell. A single turn of platinum wire is placed around the dumbbell that is suspended in a symmetrical non-uniform magnetic field.

Figure 6-2 The Measuring cell in theory



When the surrounding gas contains oxygen, the dumbbell spheres are pushed out of the magnetic field by the change in the field that is caused by the relatively strong paramagnetic oxygen. The torque acting on the dumbbell will be proportional to the paramagnetism of the surrounding gas and, therefore, it can be used as a measure of the oxygen concentration.

The distortion of the dumbbell is sensed by a light beam and projected on a mirror attached to the dumbbell whereof it is reflected to a pair of photocells. When both photocells are illuminated equally, the output will be zero. The output from the photocells is connected to an amplifier, which in turn is fed to the feedback coil of the measuring cell. If the oxygen content of the gas sample changes, the corresponding current output of the amplifier, which is proportional to the oxygen content, produces a magnetic field in the feedback coil opposing the forces and thereby causing the dumbbell to rotate.

Figure 6-3 Principle of operation

Since the feedback current from the amplifier is proportional to the oxygen content of the gas sample, the output signals that are produced by the amplifier will be accurate and linear. The paramagnetic susceptibility of oxygen varies inversely as the square of the absolute temperature. To provide compensation for changes in analyzer temperature, a temperature sensitive element in contact with the measuring cell assembly, is included in the feedback current circuit.



7. Preparations for Operation Warning: This is a general-purpose analyzer, not suitable for hazardous areas. High-pressure oxygen is very dangerous. Virtually any material will burn in it, possibly explosively. It is essential that any persons using this analyzer are aware of the dangers of oxygen, and take all appropriate precautions.

7.1. Power On Turn ON the power switch on the rear panel. The digital panel meters should illuminate. Allow the instrument to warm up for approximately one hour. It is preferable, but not essential, that zero gas flow through the instrument during warm-up.

0

I

Figure 7-1 AC Power Switch, Connector, and Fuse

Note: DO NOT introduce the sample gas UNTIL the analyzer has warmed-up. This will help prevent condensation from forming in the sample cell.

7.2. Zero Adjustment After the one-hour warm-up period, flow zero gas (see Section - Gases) through the instrument at a rate of about 1 liter/min. Adjust the zero control on the front panel until the digital meter (or analog output) is exactly at zero. To achieve final stability, the analyzer may require some additional warm-up period/up to four hours (depending on variables in the analyzer's environment).

7.3. Span Adjustment Flow span gas through the instrument at about 1 liter/min. Adjust the span control on the front panel until the digital meter or analog output is reading the value corresponding to the span gas concentrations.

Note: Span gas concentration should not be less than 80% of the range to be spanned. Note: On the 0-25% range of the analyzer ambient air may be used as span gas. While ambient air is flowing to the analyzer, adjust the span potentiometer to 20.9% O2.

7.4. Zero and Span Calibration Frequency

The zero and span levels should be checked and/or calibrated daily or as often as mandated.



8. Start-Up & Routine Operation Prepare and check the sample system. Adjust the flow of sample gas to about 1 L/min. The instrument should show a meter indication. The paramagnetic oxygen analyzer is designed for extended operation and may be left switched ON continuously.

8.1. Sampling System Note: High-pressure oxygen is very dangerous. Virtually any material will burn in it, possibly explosively. It is essential that any person using this analyzer is aware of the dangers of oxygen, and take all appropriate precautions. The analyzer's sampling system consists of:

1. An internally mounted in line particulate filter

2. A sample pump and flow meter (optional)

3. A sample capillary that controls the sample flow rate to the sensor at 0.2 LPM (or 0.5 depending upon model of O2 sensor.

4. A precision controlled relief valve.

The relief valve maintains a constant inlet pressure to the sample capillary and reduces response time by providing a bypass loop to the exhaust for excess sample.

The analyzer is designed to measure a clean dry sample gas that has been conditioned to remove moisture to prevent condensation in the analyzer. Some applications may require additional sample conditioning, dependent upon the specifications of the sample gas to be measured.

4.IN-LINE FILTER (MF2) CUSTOMER SUPPLIED.

3.INLET & OUTLET CONNECTIONS ARE 1/4” OD TUBE.

2.SAMPLE FLOW RATE: 0.5 L/min to 2.0 L/min.

1.SAMPLE PRESSURE: 3-5 PSIG (NOT REQUIRED WITH OPTIONAL SAMPLE PUMP).

UNLESS OTHERWISE SPECIFIED.NOTES:

SAMPLEINLET

SAMPLEINLET

IN

MF240µ

IN

MF240µ

OUT

OUT

RV1

RV1

MF15µ NV1

P1 C1O2 SENSOR

Fl1

MODEL 100PWITH OPTIONAL FLOWMETER & SAMPLE PUMP

MF15µ NV1

C1O2 SENSOR

Fl1

MODEL 100PWITH OPTIONAL FLOWMETER

NDIR SAMPLE CELL(s)

NDIR SAMPLE CELL(s)

Figure 8-1 Paramagnetic Oxygen Sample flow



8.2. Cross sensitivity of gases The paramagnetic measuring principle is based on the very high magnetic susceptibility of oxygen. In comparison to oxygen, other gases have such a minor susceptibility that most of them are insignificant. Exceptions to this are the nitrogen oxides. However, as this gas is in most cases present in a very low concentration, the error is still negligible.

8.2.1. Example 1 The residual oxygen percentage is measured in a closed carbon dioxide (CO2) atmosphere. The "zero calibration" is done by means of nitrogen (N2).

According to the list of cross-sensitivities, the error for 100 % CO2 at 200°C is -0.27%. In order to obtain a higher accuracy, this means for the zero calibration that the reading should be adjusted at +0.27% with N2, in order to compensate the error of CO2.

Since the values of cross-sensitivities are based on 100 Volume percentage of that particular gas, the error at 50% by volume CO2 and 50% by volume N2 is - 0.135%.

8.2.2. Example 2 Given the following gas composition at a temperature of 20° C:

5% volume Oxygen (O2) +100.00 x 10-2 x 5 = +5.0000

40% volume Carbon Dioxide(CO2) -0.27 x 10-2 x 40 = -0.1080

1% volume Ethane(C21-14) -0.43 x 10-2 x l = -0.0043

54% volume Nitrogen (N2) 0.00 X 10-2 x 54 = 0.0000

Gives a reading (%by volume) of: +4.8877

As this example shows, the total error (5.000 minus 4.8877) is - 0.1123.



Table 8-1 Cross Sensitivity of gases

All values based on nitrogen 0% / oxygen 100% Gas Formula 20oC 50oC

Argon Ar -0.23 -0.25 Acetylene C2H2 -0.26 -0.28 Acetone C3H60 -0.63 -0.69 Acetaidehyde C2H4O -0.31 -0.34 Ammonia N3 -0.17 -0.19 Benzene C6H4 -1.24 -1.34 Bromine Br2 -1.78 -1.97 Butadiene C4H6 -0.85 -0.93 Isobutylene (CH3)2CH=CH2 -0.94 -1.06 n-Butane C4H10 -1.10 -1.22 Chlorine CL2 -0.83 -0.91 Hydrogen Chloride HCL -0.31 -0.34 Nitrous Oxide N2O -0.20 -0.22 Diacetylene (CHCl)2 -1.09- -1.20 Ethane C2H4 -0.43 -0.47 Ethylene Oxide C2H4O2 -0.54 -0.60 Ethylene C2H4 -0.20 -0.22 Ethylene Glycol CH2OHCH2OH -0.78 -0.88 Ethylbenzene C8H10 -1.89 -2.08 Hydrogen Fluoride HF +0.12 +0.14 Furan C4H40 -0.90 -0.99 Helium He +0.29 +0.32 n-Hexane C6H14 -1.78 -1.97 Krypton Kr -0.49 -0.54 Carbon Monoxide CO -0.06 -0.07 Carbon Dioxide CO2 -0.27 -0.29 Methane CH4 -0.16 -0.17 Methanol CH4O -0.27 -0.31 Methylene Chloride CH2Cl2 -1.00 -1.10 Neon Ne +0.16 +0.17 n-Octane C8H18 -2.45 -2.70 Phenol C6H6O -1.40 -1.54 Propane C3H8 -0.77 -0.85 Propylene C3H6 -0.57 -0.62 Propene CH3CH=CH12 -0.58 -0.64 Propylene Oxide C3H6O -0.90 -1.00 Propylene Chloride C3H7Cl -1.42 -1.44 Silane SiH4 -0.24 -0.27 Styrene C7H6=CH2 -1.63 -1.80 Nitogen N2 -0.00 -0.00 Nitrogen Monoxide NO +42.70 +43.00 Nitrogen Dioxide NO2 +5.00 +16.00 Oxygen O2 +100.00 +100.00 Sulfur Dioxide SO2 -0.18 -0.20 Sulfur Fluoride SF6 -0.98 -1.05 Hydrogen Sulfide H2S -0.41 -0.43 Toluene C7H8 -1.57 -1.73 Trichloroethylene C2HCl3 -1.56 -1.72 Vinyl Chloride C2H3CI -0.68 -0.74 Vinyl.Fluoride CH3F -0.49 -0.54 Water H2O -0.03 -0.03 Hydrogen H2 +0.23 +0.26 Xenon Xe -0.95 -1.02



9. Mechanical Zero Adjustment (Not required with some sensor models) This adjustment depends upon sensor model and may be periodically required over the life span of the analyzer, or whenever the front panel zero adjustment has reached its limit. Note: Always check for gas leaks prior to making this adjustment, especially when the zero potentiometer is at its counter-clockwise limit. a) Place the front panel zero adjustment to its mid-setting (5.0 on the dial.)

b) Introduce N2 into the analyzer at a flow rate of 0.5-2.0 L/MIN.

c) Remove the screws securing the top to the chassis and lift off the cover of the analyzer

d) Locate and remove the rubber ‘boot’ that covers the O2 sensor.

e) Loosen the locking screw that secures the adjusting screw for positing the photo-sensor on the detector assembly. Only loosen the locking screw enough to permit the necessary adjustment (see Figure 8-1.)

f) Turn the adjusting screw as required to give an indication of approximately 0.00 on the digital display.

g) Carefully tighten the locking screw and replace the rubber ‘boot’ removed in step d).

h) Observe the digital display and turn the front panel zero adjustment to achieve reading of 0.00 in the display.

i) The zero adjustment should be between 4.0 and 6.0 on its dial. If not, repeat steps d) though h) until no further adjustment is required.

Adjusting Screw

Locking Screw

Loosen

Photo DetectorsCircuit Board

Photo DetectorMounting Block

Adjust

Figure 9-1 Oxygen sensor adjustment


SUPPLEMENTAL OXYGEN MANUAL FOR MODELS … · SUPPLEMENTAL OXYGEN MANUAL FOR MODELS 100, 200, 300...

Documents

Transcript of SUPPLEMENTAL OXYGEN MANUAL FOR MODELS … · SUPPLEMENTAL OXYGEN MANUAL FOR MODELS 100, 200, 300...