2 . T e c h n i c a l System Description
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B. Braun Avitum AG
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SW 9.xx
Phase 2:
After phase 1 is completed there is an automatic switch to the filled balance
chamber BK2 to obtain a constant flow in the dialyser. The complete cycle is
repeated in phase 2, i.e. valves VDEBK2 and VDABK2 are opened. The balance
chamber BK2 is filled via valve VDABK2. Simultaneously the dialysate is drained
from the balance chamber BK2 via valve VDEBK2. Phase 2 is completed and the
membrane is in left position (see figure).
Simultaneously the balance chamber BK1 is filled with fresh dialysate.
Therefore valve VEBK1 is opened. Valve VABK1 is also opened, to initiate the
flow path for the used dialysate to the drain. The membrane moves to the right
position.
The outlet fluid volume is equal to the returned fluid volume, due to the closed
balance chamber system
The fluid volume removed from the closed system via the ultrafiltration pump
UFP is replaced from the blood in the dialyser and equals the precise
ultrafiltration volume.
The system is initialised in preparation, i.e. the membrane sensors are
automatically calibrated and the speed of the flow pumps FPE and FPA are
determined. Thus a synchronisation of the membranes is guaranteed, and the
pump speeds for the desired flow are determined.
DDE
VBP
FBK2
RVFPA
open
closed
LAFS
VZ
VLA
VDA
VABK2
VDABK2
VABK1
VDABK1
BK2
BK1
VEBK2
VDEBK2
VEBK1
VDEBK1
MSBK2
MSBK1
VDE
LA
UFP
BL
FPE
PDA
FPA
8
8
Fig. : Phase 2 Balance Chamber
