Filter Technology
ATEX classification
Identification
Maximum gas temperatures
The pages referred on this page are part of the manual
delivered with our filters.
The page Technical support and spare parts instructs on
how to identify the physical machine.
The page Machine data states various parameters related
to the ATEX issues.
If the temperature of the gas led to the filter leads to a
higher surface temperature of the filter housing than
allowable, the surface temperature can be brought down
to an acceptable level by thermally insulating and
cladding the hot components.
See "Maximum surface temperatures" below.
The maximum allowable gas temperature must be stated
in the plant operation manual, in order to avoid operation beyond this limit.
Data evaluation
Prior to installation of the filter, it should be decided if
the following filter specifications are all adequate for the
intended installation:
1 The Equipment group and category rating.
2 The sub component temperature class.
3 The maximum gas temperature.
All three issues are described in this document.
The Equipment group and category rating
The Equipment group and category referred on the
Machine data page should be read as follows:
The Filter unit i.e. the filter housing and the
components mounted directly on same comply with the
referred equipment group and category.
Other equipment operating as part of the filter is not
classified in this field. The rating on these components
should be read from the documentation for these
components.
Examples:
If the Filter unit is built for Ex II 2D (rated on the
machine data page) , but the electric filter control is only
rated Ex II 3D, the control unit may not be installed in
the same location as the filter.
Logically, e.g. a filter unit rated for ExII 2D, which is
designed for installation in zone 21, can be installed in
zone 22 as well, if desired.
A filter unit rated for ExII 3D is designed for use in zone
22 and may not be installed in other zones.
Maximum surface temperatures
The maximum allowable surface temperature is
determined in relation to:
Dust clouds
The temperature of all surfaces which can come into
contact with dust clouds, shall not exceed 2/3 of the
minimum ignition temperature in °C of the dust cloud
concerned.
This is the case for Ex equipment
Category 1 ..... Even in the case of rare malfunctions.
Category 2 ..... Even in the case of malfunctions.
Category 3 ..... In normal operation
Dust deposits
The temperature of all surfaces on which dust can
deposit must be below the ignition/glowing temperature
of the dust concerned with a safety margin.
This is the case for Ex equipment
Category 1 ..... The thickest layer foreseeable must be
assumed, even in the case of rare
malfunctions.
Category 2 ..... A layer of dust, even in the case of
malfunctions.
Category 3 ..... A layer of dust.
The sub component temperature class
The page Machine data states a Sub component
temperature class.
The sub component temperature class indicates the
lowest temperature class (highest surface temperature) of
any component forming part of the Filter unit. This
temperature class must satisfy the criteria described in
section "Maximum surface temperatures".
Temperature class
T1
T2
T3
T4
T5
T6
Simatek A/S
For a maximum layer thickness of 5 mm, a safety
margin of 75 °C will be sufficient.
A lower safety margin may be used if there is proven
evidence that ignition is not to be expected.
Max. surface temperature
450°C
300°C
200°C
135°C
100°C
85°C
Phone service:
+45 5884 1596
Phone spare parts: +45 5884 1595
Phone office:
+45 5884 1500
www.simatek.com
[email protected]
[email protected]
1 05 60.1 GB
04-02