Reference Gas Monitoring - Siemens SIPROCESS GA700 Operating Instructions Manual

Measuring principle
The ULTRAMAT 7 can simultaneously measure up to 4 infrared-active measuring components.
The measurements are based on the molecular-specific absorption of infrared radiation bands
(absorption bands). ULTRAMAT 7 analyzer modules use a spectral range which includes
wavelengths of 2 to 9 µm. Although the absorbing wavelengths are characteristic of individual
gases, they may partially overlap. This results in cross-sensitivities which are reduced to a
minimum by the following measures:
• Beam splitter (gas filter)
• Double-layer detector, each gas compartment with adjustable weighting between the first
and second detector layer
• Application-specific factory-fitted interference filter
ULTRAMAT 7 analyzer modules operate according to the infrared push-pull chopped radiation
principle and are equipped with a double-layer detector.
An IR source
is emitted in the beam splitter
beam equally between the sample gas and reference gas compartments.
The chopper
relaxation of the receiver.
The reference beam passes through the reference chamber
⑥
virtually unattenuated. The detector chamber
concentration of the gas component to be measured.
The sample beam, by contrast, passes through the sample chamber
and enters the detector chamber
depends on the respective sample gas concentration.
The detector is designed as a double-layer detector. The detector layer at the source end serves
primarily to absorb the middle of the band. The band edges, however, are absorbed equally by
both of the layers.
The detector layers at both compartments of the detector are pneumatically connected to each
other via a microflow sensor
detector into an electrical signal.
The weighting between the first and second detector layer is preset to a dew point of 4°C by
default at the factory using the decoupler. This minimizes the effect of interfering components.
To ensure the long-term stability of the measured value, the ULTRAMAT 7 analyzer module
supports the predictive self-diagnostics of the analyzer. This function enables you to plan
maintenance measures in a timely manner.
4.5.3

Reference gas monitoring

Only the device versions of the ULTRAMAT 7 with a flow-type reference end are equipped with
reference gas connections. The reference gas connections are implemented as nozzles with an
outer diameter of 6 mm.
To connect the reference gas supply and return lines use only such gas-contacted connecting
parts that are suitable for the connection and the reference gas.
Rack-mounted device
Operating Instructions, A5E31874006-12
①
with a temperature of approximately 600 °C generates infrared radiation which
③
. The beam splitter
④
produces a periodic modulation of the infrared radiation, and thus enables
⑩
⑨
. This sensor element converts the pressure difference in the
③
acts as a filter chamber and divides the
⑤
⑥
is filled with a precisely defined
attenuated to various degrees. The degree of attenuation
Description
4.5 ULTRAMAT 7
and enters the detector chamber
⑫
filled with sample gas
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