Siemens Servo i, Руководство по обслуживанию, Страница: 23 / 70

E382 E407E 061 01 01 02
Siemens-Elema AB
Servo … Description of functions
3 - 7
3
Bacteria filter and expiratory pressure tube
Via a B
ACTERIA
F
ILTER
inside the cassette, the E
XPIRATORY
P
RESSURE
T
UBE
connects the cassette to the E
XPIRATORY
P
RESSURE
T
RANSDUCER
. The filter and the connector are
integrated parts of the cassette. The filter protects
the transducer on PC 1781 P
RESSURE
T
RANSDUCER
from
contamination.
Expiratory valve
The E
XPIRATORY
V
ALVE
consists of a membrane in the
cassette that is operated by the axis of the E
XPIRATORY
V
ALVE
C
OIL
. The valve is fully open as long as no power
is supplied to the coil.
During normal conditions, the membrane will not
need replacement during the lifetime of the expira-
tory cassette. However, if the membrane for some
reason has become defective, it can be replaced.
Refer to instructions in chapter ”Service procedures”.
Before replacing the membrane, check the remaining
operating time for the expiratory cassette. If less than
10–15% operating time remains, it is recommended
to replace the complete expiratory cassette.
Expiratory valve coil
The movable axis of the E
XPIRATORY
V
ALVE
C
OIL
controls
the opening of the E
XPIRATORY
V
ALVE
by pushing the
valve membrane into desired position. The power
supply to the coil is regulated so that the remaining
pressure in the patient system, towards the end of
the expiration time, is kept on the PEEP level
according to front panel setting.
Expiratory outlet with expiratory one-way valve
The gas from the patient system leaves the ventilator
via this E
XPIRATORY
O
UTLET
. Backflow via the cassette is
prevented by the E
XPIRATORY
O
NE
-W
AY
V
ALVE
. Its rubber
membrane and valve seat are integrated parts of the
E
XPIRATORY
O
UTLET
.
PC 1786 Expiratory channel cassette
The PC 1786 E
XPIRATORY
C
HANNEL
C
ASSETTE
is a
connection board, integrated into the E
XPIRATORY
C
ASSETTE
, for the U
LTRASONIC
F
LOWMETER
and for the
H
EATING
F
OIL
. It connects to PC 1785 mounted in the
expiratory cassette compartment.
Includes also an ID PROM. The ID information can be
read by the Servo
… System.
PC 1785 Expiratory channel connector
The PC 1785 E
XPIRATORY
C
HANNEL
C
ONNECTOR
is a
connector board including signal filters that is
mounted in the expiratory cassette compartment.
It connects to PC 1786 mounted in the E
XPIRATORY
C
ASSETTE
when the cassette is docked to the expiratory
cassette compartment.
PC 1770 Main back-plane
Interconnection board for the PC boards in the lower
part of the patient unit.
The ventilators ID (Serial No.), configuration, time
stamp for preventive maintenance, etc, is stored in an
EEPROM on PC 1770. Thus, PC 1770 can only be
replaced by a factory preset PC board.
As the preventive maintenance time stamp will be
reset when replacing PC 1770, a new time stamp
must be set via the Biomed menu. In order to make
this new time stamp correct, the preventive mainte-
nance must be performed. Refer to chapter ”Pre-
ventive maintenance”.
Pressure transducers
Functional Main Blocks diagram marking: “ T ”
PC 1781 Inspiratory pressure transducer
The pressure, conveyed via the pressure tube
connected to this block, is led to and measured by its
differential pressure transducer. With differential
reference to the ambient pressure, the output signal
is proportional to the measured pressure thus giving a
linear measurement in the range -40 cm H
2
O to
+160 cm H
2
O.
Technical limitation: Pressure exceeding 200 cm H
2
O
must be avoided.
PC 1781 Expiratory pressure transducer
Function identical to PC 1781 I
NSPIRATORY
P
RESSURE
T
RANSDUCER
.