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4. Technical Description
The ventilator is a computer controlled ventilator.
The computer is broken down into three electronic
subsystems that are housed in the upper
(electronic) section of the ventilator.
The three sub systems are user interface, monitor
and controller.
The interface subsystem controls the user interface,
the display and the touchscreen. The controller
subsystem regulates the pneumatic systems of the
ventilator. The monitor subsystem collects and
processes flow data and generates the alarms.
Each subsystem communicates with the other two
in a peer to peer protocol, i.e. no subsystem is in
complete control.
The ventilator is fitted with an auto-ranging power
supply that is capable of working with mains
supplies of 100V to 240V 50-60 Hertz. (Fuse ratings
T2.0AH 250V (5x20mm)).
The ventilator carries an onboard backup power
supply, which consists of sealed lead/acid batteries,
that can power the ventilator in the event of a mains
power fail. The batteries are charged from the
ventilators power supply. Both the battery supply
and mains power supply are monitored by the
ventilators other subsystems. In normal modes of
ventilation and with a fully charged battery, in a
mains power fail situation the ventilator will continue
to operate for 45 minutes to 60 minutes depending
on ventilation mode.
The pneumatic system consists of the following:
An electronic oxygen blender supplying blended gas
to a mixing chamber. The blended gas is then
controlled via solenoid valves to supply the
conventional ventilation system and the oscillatory
system.
For conventional ventilation (SLE4000 & SLE5000)
the gas is controlled by two pressure regulators that
produce positive and negative gas flows via the
forward and reverse jets.
For oscillatory ventilation (SLE5000 only) the gas
flow is controlled by four in-line high speed solenoid
valves that produce the oscillatory gas flow via the
forward and reverse jets.
See the pneumatic schematics on page 182.
The exhalation block mounts onto two jet ports one
forward/reverse and one mean pressure.
Pressure is monitored via the proximal airway port
through a pair of pressure transducers with data
being sent to the monitor subsystem.
Flow is monitored by a dual hot wire anemometer
mounted at the ET manifold with the flow data being
sent to the monitor subsystem.
Note: The SLE5000 and SLE4000 ventilators
have different pneumatic units.
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