BUCHI UV-Vis Detector C-640 - Manual (Page 33)

6 Maintenance and repairs
33 C-640 Operation Manual, Version A
6 .3 .1 Cleaning the cell window
A contaminated cell will result in a lowered light transmission which will increase the noise level and
will make zeroing difficult. The easiest way to clean the cell is to rinse the dismantled cell with suitable
solvents. Therefore the cell has be removed from the instrument. The solvent type has to be chosen
according to the type of the contamination. Either organic or inorganic solvents, or diluted solutions of
acids (e.g. H
2
SO
4
or HNO
3
diluted with distilled water in ratio 1 : 20 or 1 : 10) may be used.
After cleaning rinse the cell with pure solvent and remount it to the cell compartment and check for
any leaks while liquid is flowing through the cell.
If the system is tight perform a cell test.
If this simple cleaning procedure did not solve the problem, contact the BUCHI service support or
replace the cell windows.
6 .3 .2 Replacing the cell windows
If a replacement of cracked or contaminated windows becomes necessary or if the optical path of the
preparative cell shall be changed you have to disassemble the cell:
• Remove the four screws a and the nuts b.
• Take away the cell covers .
• Take away the window cover .
• Carefully remove the cell window .
• Take away the PTFE sealings .
2 1 3 4 5 6 3 4 5 6
Figure 6-1: Disassembling the cell
Note
To facilitate the removal of the cell window, the pressure inside of the cell can be carefully increased
by the use of a dry syringe.
Notice
Risk of instrument damage by wrong handling.
• Never touch the cell windows with bare hands. Fingerprints will block the passage of UV
radiation through the cell window and may damage the surface of the cell window!
Insert new cell windows and (if necessary) new PTFE sealings and reassemble the cell in reversed
order as described above.