H75.0.01.6C-02
User’s guide GPH 114
Page 4 of 8
3
Product Specification
3.1 Scope of supply
GPH 114 with 9V battery
GE 114 pH- electrode with storage bottle
Operating manual
3.2 Operation and maintenance advice
1. Battery operation:
If ‘bAt’ is shown in the lower display the battery has been used up and needs to be replaced. However,
the device will operate correctly for a certain time. If ‘bAt’ is shown in the upper display the voltage is too
low to operate the device; the battery has been completely used up.
The battery has to be taken out, when storing device above 50°C. We recommend taking out
battery if device is not used for a longer period of time.
2. Treat device and sensor carefully. Use only in accordance with above specification. (do not throw, hit
against etc.). Protect plug and socket from soiling.
3. The electrode must be stored in 3 mol/l KCL (ours type: KCl3M), in order to avoid drying out (excluded
GE103)
4. The electrode has to be stored in dry rooms at temperatures between 10°C to 30°C.
Below 0°C the electrode might be damaged because of freezing of the electrolyte.
5. Our pH-electrodes can be used in a degree range from 90° to ± 45° compared to horizontal
4 pH-electrode
4.1 Design
In most cases so-called combination electrodes are used. That means that
all needed elements are integrated in a single electrode (including reference
electrode).
Sometimes even a temperature sensor is integrated.
The picture on the right shows an electrode without temperature sensor.
There are several design types for the diaphragm, but generally said it is the
connection between electrolyte and the measured solution. A blockade or
soiling of the diaphragm is often the reason for the electrodes idleness and
erratic behavior.
The glass membrane has to be treated with care. The hydrated gel layer
forms on the surface of the glass membrane, which is of highest importance
for the measurement. The electrode has to be kept wet to preserve the
hydrated gel layer (see below).
4.2 Further Information
pH-electrodes are wear parts which need to be replaced, depending on the
chemical or mechanical stress they are subjected to, if the values required
can no longer be kept even after thorough cleaning and recovery. Please
take into account that there are several materials which attack glass when
they are in water solutions; other chemicals may react with the KCl-solution
in the electrode thus causing blockings in the diaphragm.
Examples:
- with solutions containing protein, like they are used on the medical and biological sector, KCI may result
in the denaturation of the protein.
- coagulated varnish
- solutions with a relatively high concentration of silver ions
Any material depositing on the measuring membrane or the diaphragm will influence the measurements and
have to be removed at regular intervals. This can be done by means of automatic cleaning equipment.
Electrodes have to be stored in a way that they are kept wet. An adequate solution is to
store them with suitable storage bottle filled with KCl 3 M.
