Siemens Servo i, Service Manual, Page: 21 / 70

E382 E407E 061 01 01 02
Siemens-Elema AB
Servo … Description of functions
3 - 5
3
Safety valve
The movable axis of the S
AFETY
V
ALVE
P
ULL
M
AGNET
controls the opening and closing of the safety valve
membrane in the I
NSPIRATORY
P
IPE
. The pull magnet is
electrically activated (closed) from the main block
E
XPIRATORY
C
HANNEL
.
When the S
AFETY
V
ALVE
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 S
AFETY
V
ALVE
to be
opened and the inspiratory gas is let out from the
I
NSPIRATORY
P
IPE
via the S
AFETY
O
UTLET
thus enabling a
decrease in the inspiratory pressure. The S
AFETY
O
UTLET
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
Monitor 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 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 S
AFETY
V
ALVE
is
normally kept closed.
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 G
AS
M
ODULES
as well as to the S
AFETY
V
ALVE
and
to the O
2
C
ELL
and the T
EMPERATURE
S
ENSOR
.