EBARA 3SF Manual De Instrucciones De Empleo Y Manutención página 8

the operation limits specified in the manual;
- Explosion-proof pumps should be used in areas
where the surrounding temperature is from –20
to 40°C and the atmospheric pressure is from
0.8 to 1.1 bar;
- Maximum viscosity of the fluid permitted: 30
mm 2 /s (opportunely sizing the motor);
- The protection system indicated by the letters c
k b is indispensable in all cases where a category
2 product is necessary. Although a category 3
pump is sufficient, a device for controlling the
fluid level is not necessary (paragraph 7.2 – Pre-
cautions for avoiding dry running).
by ignition source control can therefore not be
used ("b");
- Pumps marked for use in the presence of group
C gases can be used with group A or B gases.
Gas and vapour classification is in accordance
with the MESG values (maximum experimental
safe gap) in conformity with EN 50014.
6. EARTH CONNECTIONS
Continuity of the metal parts is guaranteed, and FIG.
2 indicates where the pump should be earthed.
7. INSTALLATION
7.1. PRECAUTIONS FOR AVOIDING MISALIGN-
MENT OF THE MOVING PARTS
To avoid misaligning the moving parts during in-
stallation and during the life of the pump, follow
the indications given in the "INSTALLATION" pa-
ragraph of the instruction manual.
7.2. PRECAUTIONS FOR AVOIDING DRY RUN-
NING AND BREAKAGE OF THE MECHANI-
CAL SEAL
To prevent the mechanical seal from breaking, en-
sure that it is always lubricated while it works.
A reduction of the level of the liquid inside the
pump and especially irregular operations such as
dry running must be avoided through the use of
safety devices.
In order to respect the essential requisites dicta-
ted by European Directive 94/9 CE, these safety
devices must be certified and the protection me-
thod used against explosions must be selected
correctly.
8 – 3SF-3LSF-3PF-3LPF
As an example, devices ideal for this purpose are
made by Endress+Hauser (if any point is not clear,
please contact EBARA Pumps Europe S.p.A.).
FIGURES 3 and 4 illustrate how to assemble the
level control devices onto the relative switchboard,
which blocks the pump when there is no fluid (indi-
cations on how to connect and set the switchboard
are given in the specific instruction manual).
7.3. PUMP OPERATION WITH AN OBSTRUC-
TED/CLOSED DELIVERY VALVE
FIGURE 5 shows the assembly drawing of the flow
Protection
rate measurer (Mp) which must be assembled at
delivery so that the pump (P) blocks when the flow
rate falls below 5% of the maximum return point.
In this case the electric contact (C) deactivates/
activates, disconnecting the electric power supply
and rendering the pump safe.
This value guarantees respect of temperature
classification on the internal and external surfaces
of the pump.
7.4. DAMAGE CAUSED BY CHEMICAL NON
COMPATIBILITY BETWEEN LIQUID AND
COMPONENTS
Check the chemical compatibility between the fluid
and the pump parts.
7.5. CAVITATION
It is important to always check correct pump
sizing (therefore it is essential to verify the value
needed by the pump using the NPSH curves.
These curves can be found in the product general
catalogues).
7.6. HOT FLUIDS
TAB. 2 gives the maximum temperature that the
fluid can reach in each temperature classification
(these values are permitted respecting the condi-
tions expressed in point 5.3 NOTES).
It is important to install a reading device in order
to guarantee the maximum temperature of the
fluid. Should the limit value indicated in TAB. 2
be exceeded, a release apparatus should switch
the pump off.
The temperature measuring instrument must be
in conformity with the UNI EN 13463-1 norm (ca-
tegory 4 of the Machines Directive) and carry an
ATEX marking that is compatible with that of the
pump. The switchboard which guarantees inter-