EBARA EVM Série Instructions D'origine page 6

Area in which an explosive atmosphere of gas or vapour
can form in normal working conditions.
ZONE 2
Area in which an explosive atmosphere made up of a mixture
of gases or vapours would form with difficulty.
Should such a mixture appear in this area, however, it
would last for a short period only.
In plants, the person in charge must define the areas in which
explosive atmospheres can form, or select apparatuses
that are suitable for the areas and check the installation,
EN
maintenance and operation conditions;
Ex - symbol which refers to pumps designed and produced
in accordance with European norm standards;
c к b - these letters specify the type of protection;
In particular
c - production safety;
к - protection by immersion into liquid (the ignition sources
are emerged into a protective liquid in order to render
them inefficient or remove them from the explosive
atmosphere);
b - protection by ignition source control;
IIC - substance group;
T2 to T4 resp. Pump temperatures classification (the
maximum temperature of the internal and external
surface of the pump must be lower than the ignition
temperature of the atmosphere in which the gases,
vapours or clouds are present) suitable for the
corresponding gas temperature classification. The
user must therefore process fluids at a temperature
that is in conformity with this classification, keeping
in mind the indications given in the relative manual
and by current legislations;
xxxxx - registration number of the technical document
storage area;
ta - ambient temperature value.
4.3. NOTES
- The pumps in category 2G are suitable for areas 1 and
2;
- Pumps with a given temperature class are also suitable
for all higher class substances (for example pumps with
a temperature classification of T4 are also suitable for
substances with T3, T2, T1 temperature classification)
but evidently within the operation limits specified in the
manual;
- Explosion-proof pumps should be used in areas where
the surrounding temperature is from -20÷60°C EVMS,
-20÷40°C EVM and the atmospheric pressure is from 0.8
to 1.1 bar;
- Maximum viscosity of the fluid permitted: 30 mm
(opportunely sizing the motor);
- mm2/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 6.2 – Precautions for avoiding dry running).
Protection 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
6
(maximum experimental safe gap) in conformity with EN
60079-0.
5. EARTH CONNECTIONS
Continuity of the metal parts is guaranteed, and FIG. 2
indicates where the pump shoud be earthed.
6. INSTALLATION
6.1. PRECAUTIONS FOR AVOIDING
MISALIGNMENT OF THE MOVING PARTS
To avoid misaligning the moving parts during installation
and during the life of the pump, follow the indications given
in the "INSTALLATION" paragraph of the instruction manual.
6.2. PRECAUTIONS FOR AVOIDING DRY RUNNING
AND BREAKAGE OF THE MECHANICAL SEAL
To prevent the mechanical seal from breaking, ensure 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 dictated by
European Directive 2014/34/EU, these safety devices
must be certified and the protection method used against
explosions must be selected correctly.
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 (indications on how to
connect and set the switchboard are given in the specific
instruction manual).
In this case, the pump filling actions are modified as follows
(see instruction manual).
Even though these figures represent two different sensors
(a diapason and a conductive sensor), the filling operations
remain the same.
Proceed as follows:
- Unscrew the hexagonal tap (marked by the letter A).
The connecting elements must be compatible with the
fluid;
- The control switchboard connected to the sensor
should indicate that no fluid is present;
- Using a funnel, fill the pump with process fluid until it
overflows;
- Screw the hexagonal tap A on again until it locks, in
order to prevent air infiltration;
- Unscrew the hexagonal tap A1 (this tap also acts as a
breather). Should it be used for breathing, pay atten-
tion to the exiting liquid or vapour - the direction of the
jet is sideways to the hexagonal tap.
- Using a funnel, fill with liquid until overflowing (this tap
makes it possible to fill up to the sensitive part of the
/s
2
sensor);
- Immediately after having filled the last section (where
the sensor is positioned) with fluid, the sensor should
indicate the presence of liquid on the switchboard;
- Screw the hexagonal tap A1 on again until it locks, in
order to prevent air infiltrations;
- Follow the instructions.
When choosing the level switch (FIGS. 3 and 4 indicate
two devices, a diapason and a conductive sensor), the
following technical data should be taken into conside-
ration:
- The product temperature field that is to be measured;
- The maximum pressure to which the device is