GE Centiva/5 Plus, Technical Reference Manual

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2 Theory of operation
TRM, Centiva/5 Plus, M1047448/CM-922026, rev. 3.50.a of 11/05 2-15
Free breathing valve
Overpressure relief valves
O2 sensor
Patient connection
Expiratory valve
Expiratory flow
To avoid sub atmospheric pressure a free breathing valve (P 19) allows ambient air
intake in case of a gas supply problem.
To avoid airway pressures beyond a level of 75 mbar (cmH2O) a passive over
pressure relief valve (P 20) is provided. To avoid airway pressures beyond an
adjustable level, set by the Pmax setting, an active over pressure relief valve (P 21)
is provided.
The inspiratory O2 sensor (EB S20) is located within the inspiratory port.
The breathing circuit (P 24) connects the machine via the inspiratory port (P 23)
and the expiratory port (P 26) to the patient.
The airway pressure within the system is controlled by the expiration pressure valve
(P 27).
A flow screen (P 29) is built into the expiratory valve assembly and generates a
differential pressure from the generated flow, which is measured by the Exp. flow
pressure sensor (EB E01. The offset valve (P 28) allows zeroing the pressure sensor
(pneumatically) for online offset calibration. The second port of the differential
pressure is ambient.