Reference Gas From The Gas Cylinder; Checking The Reference Gas Flow; Sample Gas Inlet Conditions; Checking The Sample Gas Path For Leaks - Siemens SIPROCESS GA700 Quick Start Manual

7.3.2

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.
7.3.3

Checking the reference gas flow

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.
7.3.4

Sample gas inlet conditions

Prevent condensation of the sample gas in the gas path with suitable measures, for
example:
● Connect a cooler or condensate separator upstream of the device.
● Heat the device.
7.3.5

Checking the sample gas path for leaks

The tightness is checked with air or nitrogen (test gas) at the operating temperature.
The leak rate is determined in accordance with the pressure drop method. The pressure of
the gas (air or nitrogen) enclosed in the gas line is monitored for a defined period. The size
of the pressure drop is a measure of the tightness of the gas line.
Procedure - devices with pipes
1. Close the reference gas inlet.
2. Connect the sample gas outlet to a pressure measuring instrument.
3. Apply pressure of approximately 3 000 hPa (absolute pressure) to the sample gas inlet.
Quick Start
Compact Operating Instructions, 06/2017, A5E31805656-05
Commissioning: Preparation
7.3 OXYMAT 7
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