Fresenius Medical Care 4008 S Service Manual

Chapter 11: Functional description
Fresenius Medical Care 4008 S (Version V10) SM-EN 7/01.13 11-31
From the balancing chamber H68, the dialysate flows through the
conductivity cell CD7 with integrated temperature sensor PT3. The
measured conductivity values are indicated on the monitor in mS/cm,
related to 25 °C.
The temperature sensor PT3 has the following functions:
– Temperature compensation of the conductivity display
– Indication of the dialysate temperature
Should the actual values (temperature or conductivity) of the dialysate
exceed or fall below the limit settings, the bypass valve V26 opens, and
the dialyzer inlet valve V24 is closed. The device is now in the bypass
mode. The dialysate is discharged into the drain not via the dialyzer, but
via the secondary air separator H88b and the balancing chamber H68.
If the actual conductivity and temperature values of the dialysate are
within the set limits, the dialyzer inlet valve V24 opens. The bypass
valve V26 is closed. The dialysate flows to the dialyzer.
After the dialyzer, the dialysate which is now loaded with the urinary
excreted substances flows via the filter F73, the dialyzer outlet
valve V24b and the blood leak detector S8 into the secondary air
separator H88b. The secondary air separator H88b comprises of the
pressure transducer S9 and the level sensor S6.
A warning will be emitted by the blood leak detector S8 in case of blood
losses of 0.5 ml per minute, for a hematocrit of 0.25.
Together with the venous return pressure, the signal of the pressure
transducer S9 is evaluated and indicated on the monitor as TMP. The
fluid level in the secondary air separator H88b is monitored by the level
sensor S6. The secondary air separator H88b ensures that no air can
enter the balancing chamber H68. Any presence of air bubbles in the
balancing chamber H68 would cause balancing errors.
The dialysate is pressed through the flow pump P21 into the balancing
chamber H68. As mentioned above, the balancing chamber valves are
reversed by the current rise pulses of the drive motor of the flow
pump P21. Using the speed of the flow pump P21, the dialysate flow
can be adjusted in the dialysis program: 300, 500 and 800 ml/min. In the
cleaning programs, the flow of the dialysate is fixed.
The relief valve A78 is used to limit the pressure of the flow pump P21
before the balancing chamber to approx. 2 bar.
After the balancing chamber H68, the dialysate flows though the outlet
valve V30, the heat exchanger H77 and the drain valve V87 into the
drain.
The recirculation valve V86 and the drain valve V87 serve to recirculate
fluid during the hot rinsing and disinfection programs.

Fresenius Medical Care 4008 S Specifications

General

Brand	Fresenius Medical Care
Model	4008 S
Category	Medical Equipment
Language	English