Dry Operation - Sanremo Milano LX SAP Instruction Booklet

ENGLISH
Warning – correct use of rotary pumps
1-Proper Alignment of Pump and Motor
On occasion the noise of a motor-pump assembly is caused by a poor alignment.
When the coupling between motor and pump is rigid, the pump rotor and the motor rotor may
be out of axis. If this condition is maintained over time the most likely damage is seizure of the
pump.
An efficient solution of this problem is the use of an elastic coupling between pump and motor.
Fluid-o Tech supplies an optional kit code N. 10051020.
2-Quality of Water.
Tight mechanical tolerances of components and materials used for rotary vane pumps require a
very clean water, free from suspended particles. Sand, deposits on connecting pipes or the resins
of the sweetener, when flowing through the pump, may scratch graphite parts causing problems
of insufficient pressure and flow rate.
If a closed loop hydraulic circuit is not available to guarantee a clean water and no sources of
contamination Fluid-o-Tech recommend to install a 5-10 micron filter between the sweetener and
the pump.
Recommended filter: food approved polipropilene wire cartridge.
Keep the filter clean.: an upstream dirty filter will create cavitation and the pump will break shortly
(see section 4).

3-Dry operation

Rotary vane pumps may operate in dry condition only for a very short time- few seconds!
Without a proper water cooling the temperature of the mechanical seal will increase very quickly
with resulting breakage. The most likely impact is a remarkable leak visible from the four drain
holes close to the motor clamp . For potential lack of feed from city water line Fluid-o-Tech recom-
mend the installation of a minimum pressure safety switch upstream from the pump.
In case of feed from a tank install on the tank a minimum level switch.
4-Cavitation
Cavitation shows when feed flow rate does not match the pump design requirement: most fre-
quent causes are dirty filters, small diameter pipes, more users on the same line.
Opening of the safety valve (generally installed upstream from pump and filter) must happen
before the pump start up. This will avoid cavitation. For the same reason closing of the safety valve
must be delayed after the pump shut down.
The most noticeable effect is an increase of noise. If cavitation continues the impact is the same
as of dry operation.
5-Back Feed of Hot Water
If a non return valve between the pump and the hot water vessel is defective the pump may come
in contact with hot water(90-100°C). Dimensional variations of components will cause seizure of
the pump.
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