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 2-10
Exp. valve heater
AIR flow
O2 flow
Exp. Valve (PEEP)
P airway
O2 sensor
Over pressure relief valve
To prevent the expiratory flow sensor from condensing water the expiratory valve
assembly is heated by the Exp. valve heater (EB E10), supplied by the base supply
via the fuse SI 41. The temperature is controlled by micro B and the heater monitor
(EB E12).
A pressure sensor for AIR supply (EB M04) tells the micro B about the pressure
status of the AIR gas supply. Micro B generates AIR flow by opening the
proportional, double staged AIR flow valve (EB M03). The AIR flow sensor (EB M01)
measures the generated AIR flow and reports this to micro B. To prevent the AIR
flow pressure sensor from drifting, the pressure sensor is periodically zeroed
(pneumatically) by use of an offset valve (EB M02).
A pressure sensor for O2 supply (EB M09) tells the micro B about the pressure
status of the O2 gas supply. Micro B generates O2 flow by opening the
proportional, double staged O2 flow valve (EB M08). The O2 flow sensor (EB M06)
measures the generated O2 flow and reports this to micro B. To prevent the O2 flow
pressure sensor from drifting, the pressure sensor is periodically zeroed
(pneumatically) by use of an offset valve (EB M07).
The expiratory valve is a magnetic proportional valve system (EB E03) that is
controlled by micro B. Built in the expiratory assembly the expiratory flow sensor
(EB E01) measures the expiratory flow via a stainless steel flow screen and a
pressure sensor. To prevent the exp. flow pressure sensor from drifting, the pressure
sensor is periodically zeroed (pneumatically) by use of an offset valve (EB E02).
The airway pressure is measured by the airway pressure sensor (EB M11). To
prevent the airway pressure sensor from drifting, the pressure sensor is periodically
zeroed (pneumatically) by use of an offset valve (EB M12).
A fuel cell type O2 sensor (EB S20) measures the inspiratory O2 concentration and
reports to micro B. Calibration is semi automatic.
A solenoid valve operates as an over pressure relief valve (EB S25) controlled by
micro B.