Endress+Hauser Memosens COS51E, Руководство по эксплуатации

Страница: 36 / 48

Repair Memosens COS51E
36 Hauser
3.
A0046343
4.
A0046415
3. Remove the old O-ring.
4. Carefully pull the new O-ring into position.
5. Mount the sensor →  37.
10.3.3 Replacing the electrolyte
The electrolyte is used up slowly during operation. This is caused by electrochemical
substance reactions. In de-energized state, no substance reactions take place, and the
electrolyte is not used up. The operating time of the electrolyte is shortened by diffusion of
dissolved gases such as H
2
S, NH
3
or high concentrations of CO
2
.
This may occur under certain conditions, in particular in the following cases:
• Anaerobic phases (e.g. denitification)
• Heavily polluted industrial wastewater, particularly at increased temperatures.
The electrolyte depletion can be logged using a suitable transmitter. By setting
warning limits it is possible to properly schedule sensor maintenance.
Theoretical operating time at p
O2
= 210 mbar and T=20 ˚C (68 ˚F)
COS51E-****TN 5 years
COS51E-****TF 1 year
Each change in the concentration and temperature affects the operating time.
Also pay attention to the safety datasheet of the electrolyte on
www.endress.com/downloads .
Generally, the following applies:
• Sensors operated close to the lower measuring range limit have a low rate of chemical
electrolyte consumption. The electrolyte does not have to be replaced for a long period.
• Sensors operated at high oxygen partial pressures (> 100 hPa) consume a significant
amount of electrolyte. The electrolyte has to be replaced frequently.
• 25 ml electrolyte (provided in the maintenance kit) is sufficient for approx. membrane
body approx. 15 times.
1. Disassemble the sensor→  34