CareFusion LTV 1200 Service Manual page 41

Ventilation gas exiting the Flow Valve is connected to the Wye and Exhalation Valve by a
patient circuit.
The Flow Sensor at the Wye measures the exhaled flow using a fixed orifice type transducer.
Transducer sensor ports are located between the patient and ventilator connection ports. The
Exhalation Valve provides the following functions:
1) Closes the exhalation port during inspiration to divert gas to the patient.
2) Opens the exhalation port during exhalation to allow patient gases to be exhausted to the
atmosphere.
3) Measures the exhaled flow using a fixed orifice type transducer. Transducer sensor ports are
located between the patient and ventilator connection ports.
The Solenoids (Pilot-in and Pilot-out) are used to control the pressure in the pressure
accumulator that is used to control the exhalation valve on the patient circuit. The activation of
the exhalation circuit controls the PEEP (positive end expiratory pressure) at the patient wye
during the expiratory phase.
A PEEP transducer is used to monitor the pilot pressure in the accumulator. This pilot pressure
is used in conjunction with the airway pressure transducer by the LTV
delivered PEEP.
A Differential Pressure transducer is provided to measure the delta pressure developed
across the flow transducer. The transducer is auto zeroed to ambient pressure and the sense
lines are purged to prevent moisture migration into the transducer.
The Oxygen Blender (LTV
and, as directed by the control system, meters the oxygen flow to meet the requirements of the
current O
% setting and ventilation flow demand. The O
2
pressure and is used by the Blender control system to compensate the oxygen delivery for
variations in oxygen inlet pressure.
The Sub-Ambient Relief Valve allows the patient to inspire spontaneously from room air in the
event of a failure of the main ventilator system. The Over Pressure Relief Valve provides an
independent mechanical means to limit the maximum inspiratory pressure. Both of these
functions are physically included in the Flow Valve Body.
The Airway Pressure transducer measures pressure at the patient airway and is used for a
feedback signal during the delivery of pressure breaths. The transducer is auto zeroed to
ambient pressure and the sense lines are purged to prevent moisture migration into the
transducer.
Page 6-2
®
1200 only) accepts pressurized oxygen from an external source
®
LTV 1200, 1150, and 1100 Ventilator Service Manual
®
software to control
Pressure transducer measures inlet
2
p/n 18603-001, Rev. J