Metrohm 838 Advanced Sample Processor Installation Instructions - Manual (Page 69)

4.2 Care and maintenance
Metrohm 838 Advanced Sample Processor, Service, maintenance, faults 63
4.2.2 Replacing the filtration membrane
Perfect condition of the filtration membrane used is absolutely essential
in order to achieve constant quality of the analysis results. Conse-
quently, this membrane must be exchanged at regular intervals.
Please follow the information in Chapter 6.1 when assessing the need
to exchange a membrane.
Please proceed as follows (see also Chapter 3.3.6) when replacing a fil-
tration membrane:
1 Preparing the ultrafiltration cell
• Detach all capillary connections on the ultrafiltration cell 28 by
unscrewing the PVDF pressure screws 22.
• Using the 6.2621.070 Allen key (5 mm) fully undo the 5
screws 46, separate the upper section 43 from the lower sec-
tion 45 and remove the sealing ring 44 and the spent filtration
membrane.
• Thoroughly rinse off the sealing ring, lower section and upper
section of the ultrafiltration cell with ultra-pure water.
Only ultra-pure water or ethanol may be used to clean the ultrafiltra-
tion cell. Organic solvents (e.g. acetone) will result in damage to the
Plexiglass cell!
2 Preparing the filtration membrane
• Remove a new 6.2714.020 filtration membrane 50 using the
6.2831.010 tweezers from the packaging and immerse it for
approx. 2 minutes in a petri dish filled with ultra-pure water
until the membrane is fully soaked with water.
3 Fitting the filtration membrane
• Place the upper section 43 of the ultrafiltration cell with the in-
side pointing upwards onto a clean paper towel.
• Fit the sealing ring 44 into the recess provided on the upper
section.
• Place the wet filtration membrane using the tweezers, centred
inside the sealing ring, onto the upper section.
It is imperative that the filtration membrane be soaked with water be-
fore inserting it into the filtration cell since this causes it to expand. If it
is inserted dry, this will then lead to creasing and folding in the filtration
cell which may result in blockage of the cell.