IMT Analytics CITREX H3, User Manual

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37
15
Appendix
IMT Analytics AG
Flow in the flow channel is determined by differential pressure measurement. To build
up differential pressure a linear flow element is used to provide flow resistance.
Δp = c
1
×
η
× Q + c
2
×
ρ
× Q
2
η
: dynamic viscosity of the gas [Pa s]
ρ
: gas density [kg/m
3
]
c
1
, c
2
: device-specific constants (channel geometry)
Dynamic viscosity
• The viscosity of the medium is its resistance to flow and shear.
• Viscosity is extremely dependent on temperature.
• The viscosity of a medium is slightly dependent on the pressure and moisture
content of the medium.
Density
• Density is the unit for the mass per unit volume of the medium.
• Viscosity is extremely dependent on temperature.
• The viscosity of a medium is slightly dependent on the pressure and moisture
content of the medium.
Triggers are used to define start and end points of cyclical signals. With regard to
pressure and flow curves the trigger makes it possible to determine inhalation and
exhalation. The resulting information constitutes the basis for ventilation parameter
calculation. If the trigger is not set properly or if it is not possible to detect a trigger,
the ventilation parameters will be calculated incorrectly or not at all.
Figure 26: Trigger
15.1 Principle of flow
measurement
15 Appendix
15.2 Trigger