How The Calomat 7 Works; Figure 3-9 Principle Of Operation Of Calomat 7 - Siemens SIPROCESS GA700 Operating Instructions Manual

Description
3.6 CALOMAT 7
3.6.1

How the CALOMAT 7 works

Overview
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②
③
Figure 3-9
How it works/measuring principle
The measuring method is based on the different levels of thermal conductivity of gases.
CALOMAT 7 analyzer modules work with a micromechanically produced Si chip, the
measuring membrane of which is equipped with thin-film resistors.
The resistors contained in the membrane are regulated for constant temperature. The
amperage required fluctuates in accordance with the thermal conductivity of the sample gas.
This raw value determined in this way is processed further electronically to calculate the gas
concentration.
The sensor is in a thermostatically controlled stainless steel enclosure in order to suppress
the effect of the ambient temperature. To rule out flow influences, the sensor is mounted in a
bore hole next to the flow channel.
38
Sample gas inlet
Measuring membrane with
thin-film resistors
Sample gas outlet
Principle of operation of CALOMAT 7
Rack-mounted device
Operating Instructions, 05/2015, A5E31874006-03