The contents of this document are subject to change without prior notice.All rights reserved. Copyright © 2004 Yokogawa Corporation of America.Printed in USA.

monitor generator purity with the

Hydrogen Purity Monitor

010101010010101001000101010010101110100000101010010101010000100100100001001010101010100101001010101010101010101010101101010000001010010010010100010001001000101000000001010101001010001000101001000100101000010100100010011100001001010000010100100010010100000010100000100000100000100000100000100000100000010000100001000100100101000010100100000100001101000010000101000000101011000000010101000100000101000001000010100000000000010001000000010000110000111100000000010100000000001100100100010001000001000100001001010100100101010010101010101001010101010100101001010100101010101010010100100100010000101001010101001000010101010010100101001010101010101001010010

Bulletin 11T3E1-E-A

External Views and Dimensions

Hydrogen Purging Standard Ranges

Density is the basic measurement, all other representations are derivedfrom the basic density data.

Prevent catastrophic failuresand lengthy downtime . . .

THE SAMPLE SYSTEMA well-designed gas sampling system can

eliminate unplanned measurement outages by

removing oil, dust and water before they foul the

instrument. Resident particulate and moisture

filters, pressure regulators, flow meters and

valves facilitate easy calibration, measurement

isolation, and stable, repeatable gas sample

conditions. Ask your sales representative for more

information about the sample system, core

monitor and gas dryer capability with our alliance

partner —

What does vigilance™ mean to Yokogawa?

For starters, always, always making sure the

products and solutions that leave our

research and development labs are the best

the world has seen - from day one

throughout your business life cycle. Our

innovative technologies and committed

experts help design, install and manage your

production systems efficiently and

dynamically. In an ever-changing business

environment, we help plan for the future to

ensure continuity and flexibility in your

automation strategies. Yokogawa goes the

extra mile to do things right. Let us be

vigilant about your business.

Yokogawa Corporation of America2 Dart Road, Newnan, GA 30265-1094, USAPhone:800­888­6400  Fax:770­254­0928www.us.yokogawa.com

Yokogawa Europe B.V.Databankweg 20, 3821 AL AmersfoortThe NetherlandsPhone: 31-33-464-1611 Fax: 31-33-464-1610

Yokogawa Electric CorporationWorld Headquarters9-32, Nakacho 2-chome, Musashino-shi,Tokyo 180-8750, JapanPhone: 81-422-52-6785 Fax: 81-422-55-1728

Yokogawa Engineering Asia PTE. LTD5 Bedok South Road, Singapore 469270SingaporePhone: 65-241-9933 Fax: 65-241-9537

Yokogawa América Do Sul Ltda.Praca Acapulco, 31 Santo Amaro04675-190 Sao Paulo SP, BrazilPhone: 55-11-548-2666 Fax: 55-11-523-6242

Represented by:

Range

Minimum Range

Response Time 90%

Linearity ±1 ±1 ±1

Repeatability

Long Term Stability

85 - 100

approximately 5 seconds

±0.5

±0.5/month

0 - 100

±0.5

±0.5/month

0 - 100

±0.5

±0.5/month

H2 in Airvol%

H2 in CO2vol%

Air in CO2vol%

GD402/GD40A

Model GD40 - /EJAJ1, EJAF2, EJAF3, EJAF4

EXA GD402 vs TEMPERATURE!With typical hydrogen measurement technology,sudden process temperature swings can lead tolarge purity measurement errors. The EXAGD402/GD40 gas measurement remains stablein aggressive process conditions regardless ofsharp changes in ambient or process gastemperature (Fig 2)

EXA GD402 AND CALIBRATIONCalibration is fast and simple. The HPM requiresonly two gases and usually requires less than 10minutes to calibrate.

“It takes longer to gather tools and walk to theinstrument than it does to calibrate!”Georgia Power Plant Yates, Technician

TRI GAS ANALYZERHydrogen must be replaced with breathable airbefore generator maintenance. Since H2 and airare a potentially explosive mixture, a third purgegas must be used as part of the generator outageprocess. CO2 is used to buffer the H2 from the airduring generator maintenance. The YokogawaHPM measures and outputs a separate 4-20mAsignal for all phases of the generator purgesequence.

HPMPower generators use pure hydrogen to cool

and insulate power generator electrical

windings. Inexpensive and readily available,

hydrogen is the choice insulator because its low

density and high thermal conductivity provide

the best environment for generator operation.

Contaminated hydrogen reduces generator

efficiency. Air is the most common contaminate,

originating from leaking rotor shaft seals.

Knowing the purity level of the generator

hydrogen helps plant operators avoid

conditions that place human life and expensive

machinery at risk. Monitoring hydrogen purity

with the EXA GD402 helps improve generator

efficiency and reduce operational costs. (Fig 1)

Time (hours)

Den

sity

(kg

/ m3)

Tem

pera

ture

(°C

)

DensityOven Temperature

60

40

20

0

-20

1300

1296

1290

1285

1280

1275

10 ∫C change

0 5 10 15 20 25 30 35 40 45 50 55 60

1g/m 3 / 10°C or less

Control Output vs.Sudden Temperature ChangeEffects of Hydrogen PurityA GD402/GD40

Hydrogen Purity Monitor

The GD402/GD40 hydrogen purity monitor’s

low maintenance design, self-diagnostic

capabilit ies, and easy-to-use YES/NO

programming provide a broad range of control

options to meet the demanding environments

of power producers.

It’s versatility allows easy replacement

of existing “old” hydrogen measurement

installations. It consists of a gas detector

(GD40) and a signal converter (GD402) that fit

directly into most generator installations.

WHICH MONITOR TO CHOOSE?The Yokogawa GD402/GD40 Hydrogen Purity

Monitor (HPM) helps ensure that power

generators are running with pure hydrogen. It is

a fast, accurate and reliable process gas

measurement and control device that is

unaffected by ambient temperature or vibration

and does not require reference gases or a

controlled temperature environment.

The heart of the GD40 is a unique, vibrating

cylinder, sensor technology that measures

hydrogen purity. Multi-frequency cylinder

oscillation makes the GD40’s measurement

highly resistant to errors caused by dust, oil,

vibration, and temperature changes. The

Yokogawa HPM maintains ±1% FS accuracy

and a response time (T90) of less than 5

seconds.

The Yokogawa vibrating element type Hydrogen Purity Monitorhas experienced worldwide acceptance as the new

hydrogen purity measurement for electric power generators. 0

1000

2000

3000

4000

5000

88 90 92 94 96 98 100 102

% Volume concentration

Dol

lars

per

day 800 mW

400mW

Fig. 1

Simple operation, rock-solid performance, and low maintenancedefine the Yokogawa Hydrogen Purity Monitor.

“The installations used the existing generator gas sample ports and the similarity to other

Yokogawa equipment already within the plant made the operation nearly plug and play which

greatly reduced installation and startup time.”

Senior Instrument Mechanical Foreman, TVA Kingston power plant USA comments on the installation of 9 GD402 systems.

Fig. 2

“”

Ope

rati

ng D

olla

rs p

erda

y

EXA GD402 vs TEMPERATURE!With typical hydrogen measurement technology,sudden process temperature swings can lead tolarge purity measurement errors. The EXAGD402/GD40 gas measurement remains stablein aggressive process conditions regardless ofsharp changes in ambient or process gastemperature (Fig 2)

EXA GD402 AND CALIBRATIONCalibration is fast and simple. The HPM requiresonly two gases and usually requires less than 10minutes to calibrate.

“It takes longer to gather tools and walk to theinstrument than it does to calibrate!”Georgia Power Plant Yates, Technician

TRI GAS ANALYZERHydrogen must be replaced with breathable airbefore generator maintenance. Since H2 and airare a potentially explosive mixture, a third purgegas must be used as part of the generator outageprocess. CO2 is used to buffer the H2 from the airduring generator maintenance. The YokogawaHPM measures and outputs a separate 4-20mAsignal for all phases of the generator purgesequence.

HPMPower generators use pure hydrogen to cool

and insulate power generator electrical

windings. Inexpensive and readily available,

hydrogen is the choice insulator because its low

density and high thermal conductivity provide

the best environment for generator operation.

Contaminated hydrogen reduces generator

efficiency. Air is the most common contaminate,

originating from leaking rotor shaft seals.

Knowing the purity level of the generator

hydrogen helps plant operators avoid

conditions that place human life and expensive

machinery at risk. Monitoring hydrogen purity

with the EXA GD402 helps improve generator

efficiency and reduce operational costs. (Fig 1)

Time (hours)

Den

sity

(kg

/ m3)

Tem

pera

ture

(°C

)

DensityOven Temperature

60

40

20

0

-20

1300

1296

1290

1285

1280

1275

10 ∫C change

0 5 10 15 20 25 30 35 40 45 50 55 60

1g/m 3 / 10°C or less

Control Output vs.Sudden Temperature ChangeEffects of Hydrogen PurityA GD402/GD40

Hydrogen Purity Monitor

The GD402/GD40 hydrogen purity monitor’s

low maintenance design, self-diagnostic

capabilit ies, and easy-to-use YES/NO

programming provide a broad range of control

options to meet the demanding environments

of power producers.

It’s versatility allows easy replacement

of existing “old” hydrogen measurement

installations. It consists of a gas detector

(GD40) and a signal converter (GD402) that fit

directly into most generator installations.

WHICH MONITOR TO CHOOSE?The Yokogawa GD402/GD40 Hydrogen Purity

Monitor (HPM) helps ensure that power

generators are running with pure hydrogen. It is

a fast, accurate and reliable process gas

measurement and control device that is

unaffected by ambient temperature or vibration

and does not require reference gases or a

controlled temperature environment.

The heart of the GD40 is a unique, vibrating

cylinder, sensor technology that measures

hydrogen purity. Multi-frequency cylinder

oscillation makes the GD40’s measurement

highly resistant to errors caused by dust, oil,

vibration, and temperature changes. The

Yokogawa HPM maintains ±1% FS accuracy

and a response time (T90) of less than 5

seconds.

The Yokogawa vibrating element type Hydrogen Purity Monitorhas experienced worldwide acceptance as the new

hydrogen purity measurement for electric power generators. 0

1000

2000

3000

4000

5000

88 90 92 94 96 98 100 102

% Volume concentration

Dol

lars

per

day 800 mW

400mW

Fig. 1

Simple operation, rock-solid performance, and low maintenancedefine the Yokogawa Hydrogen Purity Monitor.

“The installations used the existing generator gas sample ports and the similarity to other

Yokogawa equipment already within the plant made the operation nearly plug and play which

greatly reduced installation and startup time.”

Senior Instrument Mechanical Foreman, TVA Kingston power plant USA comments on the installation of 9 GD402 systems.

Fig. 2

“”

Ope

rati

ng D

olla

rs p

erda

y

EXA GD402 vs TEMPERATURE!With typical hydrogen measurement technology,sudden process temperature swings can lead tolarge purity measurement errors. The EXAGD402/GD40 gas measurement remains stablein aggressive process conditions regardless ofsharp changes in ambient or process gastemperature (Fig 2)

EXA GD402 AND CALIBRATIONCalibration is fast and simple. The HPM requiresonly two gases and usually requires less than 10minutes to calibrate.

“It takes longer to gather tools and walk to theinstrument than it does to calibrate!”Georgia Power Plant Yates, Technician

TRI GAS ANALYZERHydrogen must be replaced with breathable airbefore generator maintenance. Since H2 and airare a potentially explosive mixture, a third purgegas must be used as part of the generator outageprocess. CO2 is used to buffer the H2 from the airduring generator maintenance. The YokogawaHPM measures and outputs a separate 4-20mAsignal for all phases of the generator purgesequence.

Time (hours)

Den

sity

(kg

/ m3)

Tem

pera

ture

(°C

)

DensityOven Temperature

60

40

20

0

-20

1300

1296

1290

1285

1280

1275

10 ∫C change

0 5 10 15 20 25 30 35 40 45 50 55 60

1g/m 3 / 10°C or less

Control Output vs.Sudden Temperature Change

Fig. 2

THE SAMPLE SYSTEMA well-designed gas sampling system can

eliminate unplanned measurement outages by

removing oil, dust and water before they foul the

instrument. Resident particulate and moisture

filters, pressure regulators, flow meters and

valves facilitate easy calibration, measurement

isolation, and stable, repeatable gas sample

conditions. Ask your sales representative for more

information about the sample system, core

monitor and gas dryer capability with our alliance

partner —

The contents of this document are subject to change without prior notice.All rights reserved. Copyright © 2004 Yokogawa Corporation of America.Printed in USA.

monitor generator purity with the

Hydrogen Purity Monitor

010101010010101001000101010010101110100000101010010101010000100100100001001010101010100101001010101010101010101010101101010000001010010010010100010001001000101000000001010101001010001000101001000100101000010100100010011100001001010000010100100010010100000010100000100000100000100000100000100000100000010000100001000100100101000010100100000100001101000010000101000000101011000000010101000100000101000001000010100000000000010001000000010000110000111100000000010100000000001100100100010001000001000100001001010100100101010010101010101001010101010100101001010100101010101010010100100100010000101001010101001000010101010010100101001010101010101001010010

Bulletin 11T3E1-E-A

External Views and Dimensions

Hydrogen Purging Standard Ranges

Density is the basic measurement, all other representations are derivedfrom the basic density data.

Prevent catastrophic failuresand lengthy downtime . . .

THE SAMPLE SYSTEMA well-designed gas sampling system can

eliminate unplanned measurement outages by

removing oil, dust and water before they foul the

instrument. Resident particulate and moisture

filters, pressure regulators, flow meters and

valves facilitate easy calibration, measurement

isolation, and stable, repeatable gas sample

conditions. Ask your sales representative for more

information about the sample system, core

monitor and gas dryer capability with our alliance

partner —

What does vigilance™ mean to Yokogawa?

For starters, always, always making sure the

products and solutions that leave our

research and development labs are the best

the world has seen - from day one

throughout your business life cycle. Our

innovative technologies and committed

experts help design, install and manage your

production systems efficiently and

dynamically. In an ever-changing business

environment, we help plan for the future to

ensure continuity and flexibility in your

automation strategies. Yokogawa goes the

extra mile to do things right. Let us be

vigilant about your business.

Yokogawa Corporation of America2 Dart Road, Newnan, GA 30265-1094, USAPhone:800­888­6400  Fax:770­254­0928www.us.yokogawa.com

Yokogawa Europe B.V.Databankweg 20, 3821 AL AmersfoortThe NetherlandsPhone: 31-33-464-1611 Fax: 31-33-464-1610

Yokogawa Electric CorporationWorld Headquarters9-32, Nakacho 2-chome, Musashino-shi,Tokyo 180-8750, JapanPhone: 81-422-52-6785 Fax: 81-422-55-1728

Yokogawa Engineering Asia PTE. LTD5 Bedok South Road, Singapore 469270SingaporePhone: 65-241-9933 Fax: 65-241-9537

Yokogawa América Do Sul Ltda.Praca Acapulco, 31 Santo Amaro04675-190 Sao Paulo SP, BrazilPhone: 55-11-548-2666 Fax: 55-11-523-6242

Represented by:

Range

Minimum Range

Response Time 90%

Linearity ±1 ±1 ±1

Repeatability

Long Term Stability

85 - 100

approximately 5 seconds

±0.5

±0.5/month

0 - 100

±0.5

±0.5/month

0 - 100

±0.5

±0.5/month

H2 in Airvol%

H2 in CO2vol%

Air in CO2vol%

GD402/GD40A

Model GD40 - /EJAJ1, EJAF2, EJAF3, EJAF4