EBARA EVM Série Manuel D'instruction page 9

EVM atex.qxp:Evm atex
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). 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 (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
MISALIGNMENT 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" para-
graph of the instruction manual.
7.2. PRECAUTIONS FOR AVOIDING DRY
RUNNING AND BREAKAGE OF THE
MECHANICAL 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 dictated
by European Directive 94/9 CE, 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.).
29-01-2010 11:27 Pagina 9
FIGURES 3 and 4 illustrate how to assemble the le-
vel control devices onto the relative switchboard,
which blocks the pump when there is no fluid (in-
dications on how to connect and set the switch-
board 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
attention to the exiting liquid or vapour - the di-
rection 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 sensi-
tive part of the 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 in-
dicate two devices, a diapason and a conductive
sensor), the following technical data should be
taken into consideration:
- The product temperature field that is to be measured;
- The maximum pressure to which the device is
subjected;
- The fluid viscosity;
- The sensor material (compatibility with the fluid)
and the casing material;
- The ATEX protection classification in conformity
with ATEX pump homologation
Correct assembly of the fluid monitoring device in-
side the pump ensures that the seal is always lu-
bricated by the fluid during operation.
EVM – 9