ATEX
18
GA03107_002_A4 - 09/2015 - © Oerlikon Leybold Vacuum
Example for T3 without temperature monitoring
A RUVAC WA 501 ATEX Kat. 3 (i) / (o) is being operated together with a liquid
ring pump and a steam ejector pump. The liquid ring pump and the steam ejec-
tor pump generate a pumping speed of approximately150 m
3
/ h.
ATEX requirement: The WA 501 must not exceed the temperature T3 (200 °C).
The nominal pumping speed of the WA 501 is 505 m
3
/ h.
k
th
= Nominal pumping speed RUVAC / nominal pumping speed backing
pump = 505 m
3
/ h / 150 m
3
/ h
= 3.36
According to equation (1):
p
a
= p
const
/ k
th
p
const
(T3) = 34 mbar (see table)
Thus it follows that:
p
a
= 34 mbar / 3.36 = 9.2 mbar
Result
Under these conditions the WA 501 may be switched on at an inlet pressure (=
process pressure) of
9.2 mbar
and continuously operated. Here the require-
ments of temperature classification T3 are fulfilled at all times.
Example for T3 with temperature monitoring
Under these conditions the WA 501 may be switched on at an inlet pressure (=
process pressure) of
9.2 mbar
and continuously operated. Here the require-
ments of temperature classification T3 are fulfilled at all times.
A RUVAC WA 501 ATEX Kat. 3 (i) / (o) is being operated together with a liquid
ring pump and a steam ejector pump. The liquid ring pump and the steam ejec-
tor pump generate a pumping speed of approximately150 m
3
/ h.
ATEX requirement: The WA 501 must not exceed the temperature T3 (200 °C).
However, the process pressure (p
a
) is limited from the side of the system to
20 mbar.
For p
a, max. permissible
the following value was determined (see above):
p
a
= 34 mbar / 3.36
= 9.2 mbar
The maximum operating pressure for T3 is at 9.2 mbar thus below the given
process pressure of p
a
= 20 mbar. For this reason the operator must contact
Leybold before commissioning so as to clarify the possibility of T3 operation
under these conditions. Temperature monitoring with the PT100 (Kat-Nr. 155
010) will in any case be necessary above p
a
= 9.2 mbar.
In order to determine whether T3 compliance can be maintained at this process
pressure, please contact the Leybold Vacuum for a review and rating informa-
tion. For this, information on the pumping speed characteristic of your backing
vacuum pump system as well as the lengths and diameters of the connecting
lines is required.
Summary of Contents for RUVAC WA
Page 67: ...Notes 67 GA03107_002_A4 09 2015 Oerlikon Leybold Vacuum ...
Page 68: ...68 GA03107_002_A4 09 2015 Oerlikon Leybold Vacuum EC Declaration of Conformity ...
Page 69: ...69 GA03107_002_A4 09 2015 Oerlikon Leybold Vacuum EC Incorporation Declaration ...
Page 71: ...Index 71 GA03107_002_A4 09 2015 Oerlikon Leybold Vacuum ...
