Siemens Servo Ventilator 300, Service Manual

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2
Servo Ventilator 300/300A Description of functions
E382 E380E 061 01 03 01 Siemens-Elema AB 71
14 Expiratory channel
The expiratory channel conveys the
expiratory gas from the patient system
through the patient unit.
14.1 Expiratory inlet with
moisture trap
The function of the moisture trap is to
reduce the condensation of moisture in the
expiratory channel. The gas temperature is
first decreased and then increased in order
to reduce the condensation before the gas
enters the 14.4
EXPIRATORY CONNECTION TUBE
.
If moisture is condensated in the moisture
trap, it is collected in a plastic container.
Empty the plastic container if necessary.
When removing the plastic container, a built-
in valve closes to keep the patient system
tight.
14.2 Expiratory connection tube
The inside bottom of this silicon rubber tube
has a slope down towards the 14.1
EXPIRA
-
TORY INLET WITH MOISTURE TRAP
.
14.3 Expiratory flow transducer
The gas flows through the expiratory flow
transducer in two parallel channels, one
large main channel, and one small
measuring channel. The main channel is
fitted with a wire mesh net, the resistance
of which causes a certain proportion of the
gas to flow through the measuring channel.
The flow through, and the differential
pressure across, the measuring channel acts
on a small metal disc (”flag”), which, via a
metal pin presses on a small semiconductor
strain gauge. This consists of diffused
resistors on both sides of an elastic silicone
rod. The resistors are connected as a part of
a Wheatstone bridge, the other part of which
13 Expiratory pressure
The function of this main block is to
measure the pressure in the 14
EXPIRATORY
CHANNEL
and generate a signal
EXP
.
PRESSURE
via PC 1607
PNEUMATIC INTERCONNECTION
(N25:C7 from P24:C7) to the main blocks 4
MONITORING
, 6
REFERENCE
&
TIMING
and 15
VALVE
CONTROL
.
A recommendation to regularly exchange
the 13.1
BACTERIA FILTER
with its connection
tube and nipple is given in the Operating
Manual, chapters Routine cleaning, 1000
hour overhaul and 3000 hour overhaul with
complete cleaning.
13.1 Bacteria filter
This filter protects the 13.2
PRESSURE
TRANSDUCER
on the board 13.3
PRESSURE
AMPLIFIER
from contamination.
Service interval 1000 h of operation for
exchange of the inspiratory pressure
BACTERIA
FILTER
. The filter is also replaced during the
Routine cleaning.
13.2 Pressure transducer
See 12.2
13.3 Pressure amplifier
See 12.3