CSF Inox CN 2, Инструкции по установке, эксплуатации и техническому обслуживанию, Страница: 5 / 16

pag. 5
5 DESCRIPTION
The CN series pumps are single-stage centrifugal pumps with axial suction port, open centrifugal impeller
with reversed blades and independent shaft.
All models have threaded connections for fittings to DIN 11851 standards (unless otherwise requested)
and are fitted with unified mechanical seals according to EN 12756 - ISO 3069 standards, material are
chosen according to the liquid to be pumped. The clamp casing and seal design allows quick disassembly
for inspection, cleaning and maintenance.
They are intended for professional use.
These pumps are designed for applications where the liquid to be pumped :
- is not subject to pollution of any kind,
- is at a temperature between -10°C ÷ 120°C
- is chemically aggressive
They are fitted with three-phase electric motors with IP 55 protection rating.
5.1 SOUND PRESSURE LEVEL
The sound pressure level of centrifugal pumps is the following
(see table):
The measurement has been made by means of a phon-meter
placed at 1 m distance from the pump and at a height of 1.6
m from the ground.
Preliminary condition is that the pump is fixed correctly; the
above mentioned values do not take into account external
noise sources (e.g. valves, abrupt hydraulic deflections).
6 NON-PERMITTED USES
Do not use the pump with a suction pressure greater than the specified value (0.5 times the discharge
head generated by the pump).
The pump must always be used in an environment appropriate to the level of protection of the motor.
Always check this on the motor plate before installation.
WARNING THE PUMP MAY NOT BE USED IN ENVIRONMENTS WHICH REQUIRE A HIGHER LEVEL
OF PROTECTION OR A HIGHER SPECIFICATION MOTOR OR ELECTRICAL PARTS.
Components complying with the safety standards for the environment in question must be used.
7 INSTALLATION
7.1 SUCTION AND INFLOW CONDITIONS
(NPSH = Net Positive Suction Head)
NPSH of system (available NPSH)
In order to ensure that pump operation is free from cavitation, it is essential to observe the maximum
permitted suction lift ha geo max or the minimum allowable head hc geo min.
NPSH of pump (required NPSH)
The centrifugal pumps can operate correctly only if vapour has not formed inside. For this reason the
static head at the reference point for the NPSH is the centre of the impeller, that is the point of intersec-
tion of the pump shaft axis with the vertical plane that passes through the external points of the blade
inlet corners.
NPSH is the value required by the pump, expressed in metres, obtained from the performance curve. In
practice 0.5 m should be added to this value as a safety margin.
7.2 PIPING
In order to prevent the creation of harmful stresses, the suction and discharge pipes must be connected
to the pump ports without the use of force. These pipes must also be supported independently avoiding
causing stresses on the pump. The internal diameter must be the same size as the pump connections. It
must in any case not be smaller to avoid head loss and/or poor performances.
Always use elbows with large radius. If the pipe diameter changes along the line, use reduction cones,
choosing the ones that are most suitable to avoid any formation of air pockets (Pict.1).
Pump type
Sound pressure level
dB(A)
CN 1 2 poles
CN 2 2 poles
CN 3 2 poles
CN 1 4 poles
CN 2 4 poles
CN 3 4 poles
75 ÷ 80
80 ÷ 85
85 ÷ 88
< 70