EBARA EVM Supplementary User Instructions page 9

ration 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 /s (opportunely sizing the motor);
2
- 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 – Precautions for
avoiding dry running). Protection by ignition sour-
ce 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 instal-
lation and during the life of the pump, follow the in-
dications given in the "INSTALLATION" paragraph of
the instruction manual.
7.2. PRECAUTIONS FOR AVOIDING DRY RUN-
NING AND BREAKAGE OF THE MECHANICAL
SEAL
To prevent the mechanical seal from breaking, ensu-
re 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 run-
ning must be avoided through the use of safety devi-
ces.
In order to respect the essential requisites dictated by
European Directive 94/9 CE, these safety devices mu-
st be certified and the protection method used again-
st explosions must be selected correctly.
As an example, devices ideal for this purpose are ma-
de by Endress+Hauser (if any point is not clear, plea-
se contact EBARA Pumps Europe S.p.A.).
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 (indi-
cations 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 sen-
sors (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 un-
til 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 at-
tention to the exiting liquid or vapour - the direc-
tion 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 sensor);
- Immediately after having filled the last section
(where the sensor is positioned) with fluid, the sen-
sor 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 indi-
cate two devices, a diapason and a conductive sen-
sor), the following technical data should be taken in-
to consideration:
- The product temperature field that is to be measu-
red;
- 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
EVM – 9