Considerations Regarding Delivery And Suction Lines; Line Accessories - Piusi VISCOMAT 60/2 AC Instalación Uso Y Mantenimiento

Installation, use and maintenance
ATTENTION

10.3 CONSIDERATIONS REGARDING DELIVERY AND SUCTION LINES

DELIVERY The choice of pump model to use should be made keeping in mind the viscosity of the oil to be
pumped and the characteristics of the system attached to the delivery of the pump. The combina-
tion of the oil viscosity and the characteristics of the system could, in fact,create back pressure
greater than the anticipated maximums (equal to Pmax), so as to cause the (partial) opening of the
pump by-pass with a consequent noticeable reduction of the flow rate supplied. In such a case, in
order to permit the correct functioning of the pump equal to the viscosity of the oil being pumped,
it will be necessary to reduce resistance in the system by employing shorter hoses and/or of larger
diameter. On the other hand, if the system cannot be modified it will be necessary to select a pump
model with a higher Pmax.
SUCTION The pumps are characterized by excellent suction capacity. In fact, the characteristic flow rate/back
pressure curve remains unchanged even at high pump suction pressure values. In the case of oils
with viscosity not greater than 100 cSt the suction pressure can reach values on the order of 0.7 -
0.8 bar without compromising the proper functioning of the pump. Beyond these suction pressure
values,cavitation phenomena begin as evidenced by accentuated running noise that over time can
cause pump damage, not to mention a degradation of pump performance. As viscosity increases,
the suction pressure at which cavitation phenomena begin decreases. In the case of oils with viscosi-
ties equal to approximately 500 cSt, the suction pressure must not exceed values of the order of 0,3
-0,5 bar to avoid triggering cavitation phenomena. The values indicated above refer to the suction of
oil that is substantially free of air. If the oil being pumped is mixed with air, the cavitation phenomena
can begin at lower suction pressures. In any case, for as much as was said above, it is important to
guarantee low suction pressures (short hoses and possibly of larger diameter than the inlet opening
of the pump,fewer curves, filters of wide cross-section and kept clean).
ATTENTION

10.4 LINE ACCESSORIES

ATTENTION
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To maximise performance and prevent damage that could affect pump operation, al-
ways demand original accessories.
The use of hoses and/or line components that are inappropriate for use with oil or have
inadequate nominal pressures can cause damage to objects or people as well as pol-
lution. The loosening of connections (threaded connections, flanges, gasket seals) can
likewise cause damage to objects or people as well as pollution. Check all of the connec-
tions after installation and on a regular on-going basis with adequate frequency.
During initial start-up or accidental draining of the pump, fill the oil sump directly through
the suction inlet of the pump. At the end of the operation, remember to connect the hose
to the suction inlet.
When connecting the delivery and suction hoses, use the correct fittings (not supplied with
the unit) with thread seal.
For the suction, always use a hose with a min. diameter of ½" and max. length of 10 mt.
For the delivery, always use a hose with a min. diameter of ¾" and max. length of 50 metres.
It is a good system practice to immediately install vacuum and air pressure gauges at
the inlets and outlets of the pump which allow verification that operating conditions
are within anticipated limits. To avoid emptying the suction hose when the pump is
turned off, the installation of a foot valve is recommended.
It is the installer's responsibility to provide the line accessories necessary for the safe
and proper functioning of the pump.The use of accessories unsuitable for use with die-
sel fuel can damage the pump, injurepersons and cause pollution.
M0229 ML