Servo-i Ventilator System Description of functions
Revision 02 Service Manual 3 - 5
3
Temperature sensor
A Temperature Sensor is integrated into the
connector on top of the O
2
Cell. This sensor
measures the temperature inside the Inspiratory
Section.
The output signal, corresponding to the temperature
in the Inspiratory Section, is used for regulation of
the Internal Fan. The electronics for this regulation is
located on PC 1775 Plug-and-play back-plane.
Inspiratory pressure tube
The Inspiratory Pressure Tube connects the Inspira-
tory Pipe with the Inspiratory Pressure Transducer.
A bacteria filter protects the pressure transducer on
PC 1781 Pressure Transducer from contamination.
Maintenance including exchange of bacteria filter
according to User´s manual. The bacteria filter must
also be replaced during the 'Preventive
maintenance'.
Safety valve
The movable axis of the Safety Valve Pull Magnet
controls the opening and closing of the safety valve
membrane in the Inspiratory Pipe. The pull magnet is
electrically activated (closed) from the main block
Expiratory Channel.
SVX9016
When the Safety Valve is not activated, the weight of
the pull magnet axis, in combination with the design
of the valve membrane, pushes the pull magnet axis
downwards. This actuates the Safety Valve to be
opened and the inspiratory gas is let out from the
Inspiratory Pipe via the Safety Outlet thus enabling a
decrease in the inspiratory pressure. The Safety
Outlet is covered by a plastic grid.
This is normal safety (pop-off) function.
The opening conditions for the safety valve are:
• The ventilator is switched Off or Standby.
• The pressure inside the inspiratory pipe is
5 cm H
2
O above the preset Upper Pressure
Alarm limit. This condition is controlled by the
Monitoring subsystem.
• The pressure inside the inspiratory pipe is
7 cm H
2
O above the preset Upper Pressure
Alarm limit. This condition is controlled by the
Breathing subsystem.
• The pressure inside the inspiratory pipe is above
117 ±7 cm H
2
O. This is an extra safety function and
this situation will normally not occur.
• The safety valve will also be opened by some other
alarms, e. g. the Out of gas-alarm.
During startup, the pull magnet is electrically
activated so that the pull magnet axis is pushed up
(with a clicking sound). This is the normal operational
position of the pull magnet; the Safety Valve is
normally kept closed.
The safety valve opening pressure is calibrated to
117 ±3 cm H
2
O during each Pre-use check.
Inspiratory outlet
22 mm / 15 mm tube connector for the inspiratory
tube of the patient breathing system.
PC 1780 Pneumatic back-plane
Interconnecting board including connectors for
cables to the Gas Modules as well as to the Safety
Valve and to the O
2
Cell and the Temperature
Sensor.
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