Fresenius Medical Care 2008k Technical Manual page 20

1. Time constants
The overlap time (delay time) of the balancing chamber valves is always 50 ms. This time is
included in the switching time of the balance chamber (ie. switching time is 6.00 seconds means
5.95 sec. fill time plus 50 ms delay time).
Time constants of the balance chamber.
Flow rate 100 ml/min t = 18.0 s ± 10%
Flow rate 200 ml/min t = 9.0 s ± 10%
Flow rate 300 ml/min t = 6.0 s ± 10%
Flow rate 400 ml/min t = 4.5 s ± 10%
Flow rate 500 ml/min t = 3.6 s ± 10%
Flow rate 600 ml/min t = 3.0 s ± 10%
Flow rate 700 ml/min t = 2.57 s ± 10%
Flow rate 800 ml/min t = 2.25 s ± 10%
2. Rinse
Rinse can only be started if the concentrate and bicarbonate connectors are in their rinse ports, the
dialyzer couplings are connected to the shunt and the shunt door is closed.
At the beginning of rinse the hydraulics are flushed. Valves V30, V31, V32, V33, V34, V35, V36,
V37, V38, V24, V25, V39, the deaeration pump and the flow pump on and the concentrate pumps
run maximum stroke volume, V26 opens and V24/V25 closes. Every 1.45 seconds valve 30 closes
and valve 29 opens.
Every cycle the UF pump runs at 3000 ml/h, V43 alternates on/off, and the concentrate and
bicarbonate pump stroke every balancing chamber cycle. This pattern assures that all the various
parts of the hydraulics get adequately rinsed.
The rinse program lasts until it is stopped by the timer counting to 0 or by the operator. The set time
and the remaining time on rinse are displayed on the screen.
2008K Technician's Manual
HYDRAULIC OPERATION
Section III – Hydraulic Description
III-3