Table 2: Gas Factors - Teledyne 700 IR Series Instruction Manual

Infrared gas detector for combustible and co2 gases

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Table of Contents

700 IR Series

INFRARED GAS DETECTOR FOR COMBUSTIBLE AND CO

GASES

USER MANUAL

3.5.5

Set Gas Factor

Because of the IR sensor's almost universal response to combustible hydrocarbon gases, the

OLCT 700/710 IR detector can be configured and calibrated to detect any of the combustible

gases listed in the Table 2. The detected gas is referred to as the "target gas" and the span

calibration gas is referred to as the "cal gas". In cases where the cal gas is different from the

target gas, the Set Gas Factor menu function is used to maintain accuracy. This feature allows for

a significant degree of flexibility in the detection and span calibration process.

Set Gas Factor is used to make the appropriate signal sensitivity adjustment when the target gas

is different from the cal gas. This is necessary because the IR sensor has different signal strengths

for each combustible hydrocarbon gas. The Gas Factor value is adjustable from 0.2 to 5.0. It

represents the translation between the target gas and the cal gas when they are different.

To calculate the correct Gas Factor, refer to Table 2 and take the Gas Factor of the target gas

and divide by the Gas Factor of the cal gas. The calculated value is the correct number to enter

into the menu as the Gas Factor.

For example, if calibrating with methane when propane is the target gas, the correct Gas Factor

to enter would be 0.63/1.0 = 0.63.

For example, if calibrating with isobutane when ethane is the target gas, the correct Gas Factor

to enter would be 0.38/0.72=0.53.

Table 2 shows the Gas Factors of most combustible hydrocarbon gases that will be measured.

Find the gas of interest for the cal gas and the target gas and follow the above instruction. If there

is a mixture of target gases, use a weighted approach to determine the correct Gas Factor. For

example, if the target gas was 50% isobutane and 50% pentane and the cal gas was propane,

the correct Gas Factor would be calculated and entered as ((0.5 x 0.72) + (0.5 x 0.77)) / 0.63

= 1.18.

Gas

Factor

Acetic Acid

2.00

Acetone

1.21

Benzene

1.00

1,3-Butadiene

1.80

Butane

0.77

Iso-Butane

0.72

Butene-1

0.67

n-Butyl Alcohol

0.63

iso-Butyl Alcohol

0.63

Cyclohexane

0.89

Cyclopropane

0.45