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 foam in the
boiler.