Siemens SIPROCESS GA700 Operating Instructions Manual page 81

Note
Reference gas connection
Connection for an external reference gas pump (low pressure connection):
• The gas connections (4 and 3) are stainless steel pipes with a diameter of 6 mm.
Connection 4 (inlet) is connected to an external pump with a discharge pressure of
100 hPa to 150 hPa. Excessive reference gas flows from a module-internal bypass
restrictor out of connection 3 (outlet) into the ambient air. If the analyzer module is
installed in a tight control cabinet, connection 3 must be connected to the ambient air.
For more on this, refer to the nameplate of the analyzer module 7MB3020-xAxxx-xxxx;
the letter A is the 10th digit of the article no.
Reference gas connection (high-pressure connection)
• The reference gas connection (connection 4) is a stainless steel pipe with a diameter of
6 mm. It is suitable for pressure up to 5000 hPa (abs.).
Refer to the nameplate of the analyzer module 7MB3020-xCxxx-xxxx; the letter C or D is
the 10th digit of the article no.
Note
Shutting off the sample gas inlet and outlet
If you shut off the sample gas inlet and outlet, make sure that the reference gas can escape,
for example, by a 2-way valve at the sample gas outlet. Alternatively, the connection of an
overpressure valve is possible. The trigger pressure must then lie approx. 0.1 MPa above
the selected sample gas pressure.
Otherwise, excessive reference gas pressure can build up in the analyzer unit. The result
could be destruction of the internal pressure sensor or its connection to the analyzer unit.
Do not switch off the reference gas! Corrosive sample gases can destroy the microflow
sensor.
Ensure that the reference gas flowing via the sample gas outlet is discharged in an
environmentally friendly manner.
Note
Avoiding pressure fluctuations in the sample gas outlet
When the sample gas is conducted into a collective exhaust gas line, the exhaust gas line
must be free of "rapid" pressure fluctuations. If such pressure fluctuations are present,
implement the following remedial measures:
• Install a special exhaust line.
• Alternatively: Install a damping vessel (> 1 l) with a downstream restrictor between the
device and the exhaust line (pneumatic low pass).
• To avoid steam condensation in the exhaust gas line, lay the exhaust gas line as
vertically as possible.
Wall-mounted device
Operating Instructions, 05/2018, A5E31930403-06
Connecting the device
8.1 Gas connections
81