Metrohm 788 IC Filtration Sample Processor - Manual (Page 147)

6.3 Maintenance and servicing
788 IC Filtration Sample Processor
139
6.3.4 Replacing the filtration membrane
A good condition of the filtration membrane is a prerequisite for a con-
stant quality of the analysis results. Therefore, the membrane has to be
replaced regularly.
Please consider section 4.7 for evaluating the membrane type and time
of exchange.
Replace the filtration membrane as follows, see also Fig. 9 in section
2.3.8.
1 Prepare ultra-filtration cell
x Remove all tubings at the ultra-filtration cell 34 34 34 34 by opening all
PVDF compression fittings 22 22 22 22.
x Using the 6.2621.070 Allen key, completely loosen the 5
screws 46 46 46 46, separate top part 43 43 43 43 from bottom part 45 45 45 45 and re-
move sealing ring 44 44 44 44.
x Thoroughly rinse the sealing ring, bottom part and top part of
the dialysis cell with ultrapure water.
Use only ultrapure water or ethanol to clean the dialysis cell; or-
ganic solvents (e.g. acetone) will cause damage to the plexiglas cell!
2 Prepare filtration membrane
x Use the 6.2831.010 tweezers to extract a new filtration mem-
brane 50 50 50 50 (6.2714.020) from its packaging and immerse in a
Petri dish containing ultra pure water for approx. 2 min until
the membrane is completely saturated with water.
Because the filtration membrane it is stretched out thereby, it has to
be watered before inserting into the ultra-filtration cell. Otherwise, the
membrane could be crumbled in the cell, which leads to blocking.
3 Insert filtration membrane
x Lay top part 43
43 43 43 on a paper wipe with its inside facing up-
wards.
x Insert sealing ring 44
44 44 44 in the appropriate recess in the top part.
x Using the tweezers, place the wet dialysis membrane inside
the sealing ring on the top part of the filtration cell.