An electrode is placed in the steam dome and the length
of the electrode decides the level where the alarm shall occur. A low voltage
alternating current passes through the water in the boiler to the electrode and
the circuit breaks when the water level falls below the end of electrode. This
method is mainly used for high and low level alarms. It is also used, in small
size boilers, to start and stop the feed water pumps. Deposit on the electrode
is not a problem. Normal degree of coverage does not disturb the measuring
results. The measuring result is sensitive to dense
foam in the boiler.
It’s normally one electrode for
emergency low water level alarm, or two electrodes if also
high level alarm is required. This water level sensing method is also common on
small boilers for start and stop of the feed water pumps. Up to six electrodes
can be used in one electrode stand.
An electrode is placed in the steam dome and the length
of the electrode decides the level where the alarm shall occur. A low voltage
alternating current passes through the water in the boiler to the electrode and
the circuit breaks when the water level falls below the end of electrode. This
method is mainly used for high and low level alarms. It is also used, in small
size boilers, to start and stop the feed water pumps. Deposit on the electrode
is not a problem. Normal degree of coverage does not disturb the measuring
results. The measuring result is sensitive to dense