B. Braun Dialog+, Service Manual

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2 . T e c h n i c a l System Description 1 / 2 0 1 0 2 - 30
BA-TE-DE08C M.KAY
SW9xx_sm_Chapter 2_1-2010.doc/pdf <100329> yymmdd
B. Braun Avitum AG
Dialog
+
SW 9.xx
2.20.2 Degassing Circuit with
Temperature System
The degassing circuit with temperature system has the following components:
•
Degassing Bypass Valve VEB VEB VEB VEB
•
Degassing Pressure Sensor PE PE PE PE
•
Degassing Chamber EK EK EK EK
•
Degassing Pump EP EP EP EP
•
Thermal Fuse Heater TSH
TSH TSH
TSH
•
Temperature Sensor Heater Inlet TSHE
TSHE TSHE
TSHE
•
Double-Stage Heater H
H H
H
•
Degassing Temperature Sensor TSE
TSE TSE
TSE
Degassing Bypass Valve VEB Degassing Bypass Valve VEB Degassing Bypass Valve VEB Degassing Bypass Valve VEB
Degassing Pressure Sensor PE
Degassing Pressure Sensor PE Degassing Pressure Sensor PE
Degassing Pressure Sensor PE
Degassing Pump EP Degassing Pump EP Degassing Pump EP Degassing Pump EP
The degassing bypass valve VEB, pressure sensor PE, degassing chamber EK and
degassing pump EP produce and measure a negative pressure respectively. The
negative pressure is produced to separate the dissolved gas from the water.
If the degassing bypass valve VEB is closed, the flow path is reduced by means
of a bypass constriction (orifice, throttle principle) in the valve. VEB is opened
during disinfection to avoid this constriction. The desired negative pressure is
gained by controlling the degassing pump EP. The value of the negative
pressure is approx. -500 mmHg and thus always higher than the lower pressure
of the dialysate behind the dialyser. The degassing pump works with constant
speed, which is determined by the dialysate flow, unless the negative pressure
is insufficient. Then the speed of EP is increased.
Heater H Heater H Heater H Heater H
Thermal Fuse Heater TSH
Thermal Fuse Heater TSH Thermal Fuse Heater TSH
Thermal Fuse Heater TSH
Degassing Temperature Sensor TSE Degassing Temperature Sensor TSE Degassing Temperature Sensor TSE Degassing Temperature Sensor TSE
The heater H has an integrated thermal fuse TSH as a thermal cut-off. The
temperature sensor TSE measures the actual temperature at the outlet of the
heating.
Temperature Control
Temperature Control Temperature Control
Temperature Control
EK
Water Inlet Dialysate Outlet
DMV
VVBE
TSE
PE
TSHE
VVB*
VBKO*
DBK*
T
A
D
T
RVBO*
VBKS
TSBIC
VBICP*
SKBS
RVDA
VLA
H
NS
V
B
VB WT
FEP
WAB
EP
VEB
TSH
T
8
Fig. : Degassing Circuit with Temperature System
The required heat output is determined with the temperature
sensors TSE and TSHE.
A detailed description for the double-stage heater control is
described in the paragraph for the switch mode power supply
microcontroller SMPS-MC.