Requirements For Reference Gas From The Gas Cylinder; Introducing Reference Gas; Check The Reference Gas Flow - Siemens SIPROCESS GA700 Operating Instructions Manual

Commissioning
9.4 OXYMAT 7 / ULTRAMAT 7: Introduction of reference gas
In an analyzer module with a physically suppressed zero point, use an appropriate reference
gas. The concentration of the reference gas generally corresponds to the characteristic initial
value or, in special cases, the full-scale value or intermediate values.
In order to compensate for interference, the reference gas compartment can be subjected to
the purified sample gas of the measured component (absorber mode) or gas out of the
cylinder, which corresponds to the average interference gas composition.
9.4.2

Requirements for reference gas from the gas cylinder

The reference gas pressure must be 2 000 hPa above the sample gas pressure for sufficient
measuring ability.
1. Use a reference gas line with the following characteristics at measuring spans of < 2%
oxygen:
– Small cross-section, e.g. pipe diameter 2 mm
– Made of metal, e.g., stainless steel
2. Flush the reference gas line thoroughly with reference gas before commissioning.
9.4.3

Introducing reference gas

● Set the flow of sample gas and reference gas to the same level.
● Always introduce the reference gas before introducing the sample gas.
Note
Introduction of the reference gas during measurement interruptions
In the case of temporary interruption of the measurements, keep introducing the reference
gas into the analyzer module. In this way, the sample gas remaining in the sample chamber
is prevented from diffusing to the microflow sensors and possibly destroying them.
9.4.4

Check the reference gas flow

Procedure
1. Close the sample gas inlet.
2. Lay a hose with an internal diameter of 4 mm from the sample gas outlet into a beaker
filled with water.
3. Apply reference gas to the analyzer module.
The reference gas must exit slowly with 1 to 2 bubbles per second through the water filling
(at versions with flow-type compensation circuit, 2 to 4 bubbles per second). The reference
gas flow rate is then sufficient.
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Operating Instructions, 05/2018, A5E31930403-06
Wall-mounted device