FLOW
PATHS
Figure
2.3
and Figure
2.4
show the path of flow during the inspiratory
and expiratory phase in the volume limited
A/C
mode.
INSPIRATORY PHASE
In the inspiratory phase the flow pilot solenoid receives an electrical
signal which opens the solenoid. This sends a pneumatic signal to the
master valve. The master flow valve opens allowing gas to flow
through the main flow valve tubing into the main flow adapter
assembly from where it is delivered to the breathing circuit. At the
same instant the spontaneous valve (which is normally open) receives
a pneumatic signal which shuts off the spontaneous flow.
The Plateau solenoid is off and the plateau valve is closed during
volume limited modes which allows flow between the exhaust
(EXH)
and load
(L)
ports.
The PEEP solenoid receives an electrical signal during each
inspiratory cycle. This signal opens the solenoid, supplying a
pneumatic signal to the
PEEP/Exhalation valve which opens allowing
gas flow between supply
(S)
and load
(L)
ports. The gas from the
auxiliary
flow block passes through the plateau valve into the
PEEP/Exhalation valve and then into the Expiratory drive line. This
causes a pressure build up in the Expiratory drive line. The Exhalation
valve closes resulting in gas flow to the patient.
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