14
E
n
g
li
s
h
5.3 Checking purity of sample papers
Sample papers can be checked as follows:-
1. Put on a pair of clean disposable gloves.
2. Fill the 2 ml syringe with precisely 1.5 ml of high purity water.
3. Using tweezers, remove the sample paper to be checked from the pack.
4. Use tweezers to hold the sample paper and eject 1.5 ml of high purity water
onto its surface, retaining as much water as possible on the paper (Figure
2).
5. Switch the Elcometer 130 SCM400 on by pressing the red pushbutton
once. The display will show:-
6. Place the sample paper on the concentric electrodes and follow steps 5 to
10 (inclusive) in Section 4.2.
If a reading other than SALT LEVELS TOO LOW is obtained the sample paper
is too contaminated for use and should be discarded.
5.4 Removing and cleaning or replacing the electrodes
1. Remove the electrode and gasket by releasing the four retaining screws
(Figure 6).
2. To clean the electrode: Wipe the electrode, gasket, pressure plate and the
electrode well with clean tissues, ensuring all are properly dry.
3. When refitting or replacing the electrode ensure that the four retaining
screws are below the surface of the electrode.
5.5 Removing discolouration from electrode surfaces
During use, the electrode will become slightly discoloured due to surface
oxidation. This does not significantly affect operation of the Elcometer 130.
However, long term use may create heavier corrosion of the electrode surface.
This will be particularly obvious on the central electrode where a dark brown
ring will form, initially at the edge of the electrode and gradually increasing in
surface coverage. This could slightly affect the accuracy of the Elcometer 130
SCM400 and should be removed by gentle rubbing with a very fine abrasive
paper (1200 grit).
Over a period of time, or by rubbing too hard with the abrasive paper, the
electrodes may become damaged and should then be replaced - see
“Removing and cleaning or replacing the electrodes” on page 14.
SCM........Ready
