Integrative notes to the operating manual for magnetic coupling centrifugal pumps conforming to the ATEX 94/9/CE directive TCK... - TBK... – TBAK…
6
Tab. 1
Zones
Gas
Dust
Group
Category
Characteristics of the zone
0
20
1
Potentially explosive atmosphere continuously
present or for long periods
1
21
2
Potentially explosive atmosphere frequently
present during normal operation
2
22
II
3
Potentially explosive atmosphere occasionally
present or only for short periods during normal
operation
M1
Potentially explosive atmosphere continuously
present – the machine is fed by power
(pneumatics, electrics, etc.)
Coal mines
I
M2
Potentially explosive atmosphere continuously
present – the machine is not fed by power (no
pneumatics, electrics, etc.)
Tab. 2
Temperature classes (Group II)
Max. surface
temperature
Code
T…
CENELEC IEC
450°C
T1
300°C
T2
200°C
T3
135°C
T4
100°C
T5
85°C
T6
For the Group I, the classes
correspond to 150°C and 450°C
EXAMPLE:
If the max. surface temperature developed under normal
conditions by a machinery is of 115°C, this can be used
(provided that it belongs to the correct Group and Category) in
ambient where the ignition temperature of potentially explosive
atmospheres is higher than 135°C (T4). Vice versa, an
equipment classified as T3 can never be used in ambient
where the ignition temperature of potentially explosive
atmospheres is lower than 200°C.
The temperature class indicated for an equipment does not
mean up to which ambient temperature it can be used safely,
but which temperature the equipment develops on the surface
under normal conditions.
The knowledge of the temperature class - to which the equipment used in an
env
iron
ment
of potentially
explosive atmospheres appertains - is
STRICTLY
linked to the ignition temperature of the mixture consisting of air/gas/
dust which is present in the atmosphere and which generates potential hazard. Every combination of air with gas or
flammable volatile dust is characterised by a specific ignition temperature which – when reached - is sufficient to cause
a fire or an explosion of the mixture. The value of this temperature threshold depends on different factors, among
which the percentage of air and gas/dust (fuel) present in the atmosphere, the ambient pressure, the ambient
humidity, the formation of mixture layers or dust deposits, etc. All this information is not known to POMPETRAVAINI, but
must be known to the user. The conformity of an equipment according to the ATEX 94/9/EC Directive compels the
manufacturer to carry out tests on the equipment in order to establish the temperature class to which it belongs,
however the responsibility for determining if this class is safe or not for that specific use required by the customer falls
only into the competence of the customer.
The pumps manufactured by POMPETRAVAINI in conformity with the ATEX 94/9/EC Directive for the use in
environment
of potentially explosive atmospheres, classified as Zone 1 and Zone 2 according to ATEX 1999/92/EC
are all available at the minimum temperature class
T4
(135°C) (T2, 300°C, if made with packing type seals). This is the
minimum class as their surface temperature is strictly in relation with the temperature of the liquid pumped. If more
restrictive temperature classes were required (for example: T5, 100°C), a particular pump version may be taken into
consideration.
ATTENTION: The pumps do not have any kind of thermo-insulation towards the outside but
are made of metal, which is a highly thermo conducting material. Therefore, the outer surface
of a pump reaches very quickly the same temperature of the liquid pumped. If the liquid, by
which it is fed, has a temperature close to T4 (135°C), the pump must be DERATED to a less
restrictive temperature class such as T3, as the surface temperature of some components may
be higher than T4. This refers for example to the outside of a mechanical seal (see chapter 6 of
this booklet).
2 – SAFETY RULES
ATTENTION: PLEASE, READ CAREFULLY THE FOLLOWING PRESCRIPTIONS.
All precautions listed on this page must be strictly observed in order to avoid serious harm to the persons and/or
damages to the pump.