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

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 a pressure of approximately 3,000 hPa (absolute pressure) to the measuring gas
inlet. Then close the measuring gas inlet.
4. Wait for approximately 1 minute until the test gas that flowed in has reached the ambient
temperature.
5. Note the pressure.
6. Wait approximately 5 minutes. Note the pressure again.
If the pressure change is < 10 hPa, the sample gas path is adequately tight.
Procedure - devices with tubes
1. Close the reference gas inlet and, for versions with an external reference gas pump, also
the bypass outlet.
2. Connect the sample gas outlet to a pressure measuring instrument.
3. Apply a pressure of approximately 1 500 hPa (absolute pressure) to the measuring gas
inlet. Then close the measuring gas inlet.
4. Wait for approximately 1 minute until the test gas that flowed in has reached the ambient
temperature.
5. Note the pressure.
6. Wait approximately 5 minutes. Note the pressure again.
Quick Start
Compact Operating Instructions, 05/2015, A5E31805656-03
Commissioning: Preparation
7.3 OXYMAT 7
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