Datex-Ohmeda CAPNOMAC ULTIMA, Service Manual

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CAPNOMAC ULTIMA
TM
SERVICE MANUAL
4-23
4.9 Principle of Agent Identification
The anaesthetic agent identification bench identifies halothane,
enflurane, isoflurane, desflurane and sevoflurane.
The operation of the bench is based on infrared absorption at 3.3 um
range. It measures the spectrum of the gas between 3.24 um and 3.39
um. Because the spectrum of each of the anaesthetic agents is different
it is possible to identify them.
The bench consists of an infrared source, a measuring chamber, a
rotating filter and a detector. The peak wavelength of the narrow
bandpass filter changes when the angle between the light path and the
filter is changed. When the filter rotates the required spectrum is
scanned through.
The agent or a mixture of agents is calculated from the measured
spectrum using stored reference spectrums of each agent.
Figure 4.8 shows the absorption spectra of anaesthetic agents.
Figure 4.8
Anaesthetic Agents Gas Absorption Spectra
January 15th, 1997/6