Shenzhen PM-9000 Express Manual del operador descargar pdf (Pagina 232)

17.2 Sidestream CO2 Module

NOTE

•

This section is only applicable to a monitor equipped with a sidestream CO2

module.

17.2.1 Principles of Operation

WARNING

•

The CO2 module should be protected against crash and vibration.

•

Inaccurate measurement may occur when the monitor is operating in an

environment of excessively high CO2 content (>0.5%).

The monitor adopts sidestream CO2 module. The measurement of this module is based on the

feature that the CO2 molecule absorbs infrared ray. The measurement procedure is as

follows :

send the CO2 to a measurement chamber inside the module through the airway system, and

then irradiate 4.26um infrared ray at one side of the chamber and use the sensor to measure

the attenuation degree of the received infrared ray at the other side. Since the attenuation

degree of the infrared ray is proportional to the concentration of CO2, the CO2 concentration

is calculated. The measured CO2 concentration is thereafter converted into the partial

pressure under the same temperature and pressure, and then displayed.

The relation between the partial pressure and the CO2 concentration is given below:

CO2 partial pressure (mmHg)=

CO2 concentration (%)×Pamp (ambient pressure, mmHg)/100

CO2 partial pressure (kPa)= CO2 partial pressure (mmHg)/7.5

17-2

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Shenzhen PM-9000 Express Manual del operador Pagina 232