Drawing 10148 REV 0 24-11-15
Electric Agitator Instructions
On the seals
- Packing type: tighten the stuffing box before putting the tank under pressure. In case of
lateral agitators, where the seal is under the level of the liquid, an initial dripping is
considered normal, which then must be deleted by adjusting the tightening of the stuffing
box. Single mechanical type: it is not necessary to carry out any preliminary operation
since the seal is already ready for duty after the installation on the control unit of the
agitator. Check if the seal model is suitable for rotating in one or both rotation directions.
In case of lateral agitators where the seal is under the level of the liquid, make sure that it
is always in contact with the liquid. Take care that in the operations of emptying following
filling of the tank zones of accumulated air (air bubbles) around the seal are not created.
Even a few seconds of running dry can create localized overheating, which seriously
damages the mechanical seal. The damages deriving from having run dry are easily
recognizable the seal shows evident signs of burning and the counter face (if in aluminum)
may be cracked due to thermal shock. The failures caused by running dry are never
repaired under the guarantee.
- Double mechanical type: must be used with a coolant; this liquid must circulate in the
housing of the seals before starting the agitator. The liquid in circulation between the seals
must generally be maintained at a pressure exceeding 1 Atm of that in the vessel. If the
pressure of the coolant does not exceed 2 Atm, the external seal can be carried out with oil
seal ring.
7 PROBLEMS AND COUNTERMEASURES
g) The shaft vibrates: check the bearing and replace it if necessary; check that no foreign matter
is on the impeller
h) The gearbox strains at the start-up: check the bearing and replace it if necessary; check that
no foreign matter is on the impeller.
i) The thermal protection trips frequently: check the bearing and replace it if necessary; check
that no foreign matter is on the impeller; check that the impeller is not blocked in the
sediment.
j) The seal shows leaks: tighten the stuffing box in case of packing; replace the entire seal in
case of mechanical seal.
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