Nederman FlexPAK 800 DX, User Manual

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FlexPAK 800/1000 DX
19
EN
time after detection of the explosion (in milliseconds), and stops the pressure rising and
extinguishes (suppresses) the flames of the explosion.
This ensures that the filter is not stressed to a dangerous level by the explosion.
The key components of the explosion suppression system are the following:
• An explosion detection device (optical/pressure-sensitive).
•
A computer-operated control unit.
• Action elements such as pressure cylinders containing an extinguish agent with an
extra fast opening valve.
Detailed information regarding system installation, function, operation and maintenance
can be found in the suppression system manual.
3.3.3 Flameless venting
The method of flameless venting is similar to method 1 “explosion venting”. However, a
device attached to the outside of the vent will stop flames from exiting the filter vessel.
Such a device is sometimes referred to as a “quench-device” or “flameless-device”.
Common for all types of flameless devices is that the explosion is released through a
specially designed grid or mesh. The grid or mesh will allow pressure from an explosion to
be released, but prevent the explosion’s flames from exiting outside the filter vessel.
The benefit of using a flameless vent device is that it reduces the size of the risk area. This
increases the possibility of positioning the FlexPAK 800/1000 DX closer to manned areas or
equipment.
However, it must be noted that the use of a flameless device does not eliminate the risk
area. The high pressure and hot gases are still released into the surroundings, and this must
be taken into consideration when positioning the FlexPAK 800/1000 DX. Please consult your
local fire authority when determining suitable positioning of the FlexPAK 800/1000 DX with
flameless device.
Please refer to the installation and service or user manual for the flameless device supplied
with the FlexPAK 800/1000 DX to find other limitations and information regarding safe use
and service.
The use of a flameless device will also reduce the venting efficiency of the
FlexPAK 800/1000 DX. This means that the FlexPAK 800/1000 DX will not be able to be used
with explosive dust types with a higher Kst (ST type). The limit of the Kst value (ST–type) is
determined by the parameters of the specific flameless device.
3.3.4 Isolation device
An isolation device, see figure 9, item 2, is to be installed to prevent a filter explosion from
propagating back into the plant through the connected duct. The duct, see figure 9, item 3,
between the unit and the isolation device is to be pressure-resistant to an overpressure
of at least 0.5 bar (7.2 PSI) and have a minimum length as specified in the manual of the
isolation device. This is normally 4 meters for ST2 and 2 meters for ST1.
3.4 Dimensions
NOTE! Figure 2C shows the dimensions of the inlet and one side of FlexPAK 800/1000 DX.
For the dimensions of FlexPAK 800/1000 DX, see figures 2A , 2B, and 2C.