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On the variator
Always check the oil level before putting the agitator into operation. Variators are supplied without oil;
in this case see to the filling with the issued oil until reaching the maximum level visible from the special
indicator.
Some types of variators are supplied with un-drilled caps and are supplied with a vent plug, which must
be replaced when installing at the place of the cap, situated in the highest position, in order to avoid leaks
of lubricant caused by the variation of the general internal pressure during the operation. The Variators
supplied with permanent lubricant with lifelong grease lack the load, level and drain plugs.
- Continuous speed variator is achieved by turning hand wheel.
N.B.: the otovariator must be running before the adjustment can be made.
On the impeller
Do not start the agitator if the impeller is immersed in silt, unless this method of operation has been
conditioned in the design phase.
On the entire unit
Check the tightening of all the bolts and nuts. (repeat the operation after two weeks of operation).
After having carried out above-mentioned inspections, you may proceed with starting the agitator with
the pre-arranged control devices.
At the beginning of the operation, just as any machine running in, an agitator – caused by the greater
friction’s – can lead to overheating and a higher absorption of current of the motor; these problems
gradually disappear during the operation.
When a gearbox – cycle converter – is installed, it is generally advisable in time to gradually increase the
transmitted power, starting from the minimum values, or limiting it (50-70% of the maximum power) for
the first hours of the operation.
Should an excessive unforeseen absorption occur, disconnect the motor from the power grid, check the
perfect efficiency of the contact of the connections and check that the working conditions correspond to
those established, especially with regard to the density and viscosity of the liquid; in case the overload
persists, contact our technical department.
If there are vibrations, stop the agitator immediately and determine the causes that provoke it.
All the agitators are suitable for the operation with a maximum and constant level; if not foreseen in the
desing phase, avoid the operation in tanks at variable or insufficient levels.
On the seals
- Packing type: tighten the stuffing box bifore 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 localised overheating, which seriously damages
the mechanical seal. The damages deriving from having run dry are easily recognisable the seal
shows evident signs of burning and the counter face (if in aluminium) 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 bifore 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.
