Warning - Correct Use Of Rotary Pumps - Sanremo CAPRI XLC SAP Livret D'instructions

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 effi cient solution of this problem is the use of an elastic cou-
pling 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 su-
spended particles. Sand, deposits on connecting pipes or the
resins of the sweetener, when fl owing through the pump, may
scratch graphite parts causing problems of insuffi cient pressure
and fl ow 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 fi lter between the sweetener and the pump.
Recommended fi lter: food approved polipropilene wire cartridge.
Keep the fi lter clean.: an upstream dirty fi lter 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 remar-
kable leak visible from the four drain holes close to the motor clamp . For potential lack of feed from city water line Fluid-o-Tech recommend 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 fl ow rate does not match the pump design requirement: most frequent causes are dirty fi lters, small diameter pipes, more
users on the same line.
Opening of the safety valve (generally installed upstream from pump and fi lter) 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 varia-
tions of components will cause seizure of the pump.
6) Wrong connections
Pumps connectors are 3/8"NPT(conical) or 3/8" GAS(cylindrical).
Connectors with thread different from the recommended type are occasionally used. Sealing is made with a glue or with tefl on tape. If the connector is
forced it is possible to create beards; if excess sealing glue is used the extra quantity of glue may enter into the pump body.
In both cases it is likely to create a damage.
7) Pressure strokes
To avoid pressure strokes opening of solenoid valves installed downstream must happen before the start of the pump. For the same reason closing of the
valve must be delayed after stopping of the pump.
A pressure stroke may break graphite parts and damage mechanical seal causing blockage of the pump and leaks.
8) Handling
A crash on the fl oor may create deformations that will jeopardize the tight mechanical tolerances of the pump components. For the same reason be very
careful when clamping the pump to mount or demount connectors.
9) Scale build up
Scale deposits will quickly show on inner components when using hard water, not sweetened with ion exchange resins.
Scale formation increases when the pressure relief valve is used as fl ow rate regulator: the rate of scale deposition increases with increasing of closed loop
circulation.
Scale deposits cause an increase of torque, occasional seizure of the pump or a reduction of operating pressure because the pressure relief valve cannot
work properly.
To minimize this problem Fluid-o-Tech suggest to use pumps with fl ow rate matching the hydraulic circuit features.
In some circuits it is advisable to periodically remove scale with a chemical treatment.
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