Covidien Puritan Bennett 700 Series, Service Manual

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Theory of operation
Puritan Bennett™ 700 Series Ventilator System Service Manual 10070389 Rev. A 2-21
2.2.3 Inspiration manifold system
The inspiration manifold system, shown in Figure 2-11 and Figure 2-12, provides a conduit
between the cylinder and ventilator. It also senses the temperature and oxygen percentage
of the delivered gas. It includes a safety valve to vent excessive pressure. It includes a pressure
tap for the inspiration pressure transducer.
Figure 2-11. Inspiration manifold system pneumatic diagram
2.2.3.1 Component descriptions
The inspiration manifold system includes the components described below; these are shown
in Figure 2-13.
• The inspiration manifold provides a conduit between the cylinder and ventilator outlet.
A tap in the manifold connects to the inspiration pressure transducer (on the pressure
solenoid PCB). The exhalation valve port permits pressure to be supplied to the exhalation
valve (via the exhalation solenoid) during inspiration. The inspiration port permits gas
delivery (through a silicone tube) to the ventilator outlet. The inspiration port
incorporates a 22-mm ISO male conical connector for attachment of the inspiration filter
and inspiration limb of the patient tubing system.
• The oxygen sensor is a galvanic sensor that measures the percentage of oxygen delivered
from the cylinder. It produces a voltage proportional to the partial pressure of oxygen in
the delivered gas. The sensor is accurate to ± 3% of the reading. For ventilators equipped
with software revision H or later, the % O
2
is displayed if no alarm is active and the display
of the oxygen sensor reading is enabled. The ventilator alarms if the sensed oxygen
percentage is not within ± 10 percentage points of the setting.
• The inspiration manifold thermistor measures the inspiration gas temperature; this data is
used in breath delivery calculations and oxygen percentage correction.
• The inspiration pressure transducer (on the pressure solenoid PCB), an absolute type,
measures pressure at the inspiration manifold. When made with the safety valve open,
this pressure reading is used to calculate atmospheric pressure. The calculated inspiration
pressure value is a function of the inspiration pressure transducer reading minus the
atmospheric pressure.
7-00045
To air
intake
filter
From
outlet
check
valve
Thermistor
Safety
valve
From
PEEP
reservoir
Exhalation
solenoid
To
exhalation
valve
Oxygen
sensor
To
inspiratory
filter