21
Dalamatic Insertable Dust Collectors – Series DLM V
Installation, Operation and Maintenance Manual
OPERATION
Principle of operation
Dust-laden air is ducted into the chamber containing the filter elements, where it
impinges on all their outer surfaces. A layer of dust builds up on the outside of
the elements as the air itself penetrates the fabric (see fig. 15a). The clean air
emerges from the outlet header of each filter element into the cleaned air chamber
and from there it is discharged, normally via the fan, to atmosphere.
At regular intervals, governed by the controller, each element in turn receives
a short burst of compressed air from its respective jet tube (see fig. 15b). The
jet tube has a series of small-diameter jet orifices positioned adjacent to the
outlet header of each filter element (see figs. 15 and 17). These orifices are
of an optimum size and distance from the filter element, ensuring that a large
volume of air is induced by each injection of compressed air. This causes a brief,
powerful reversal of airflow through the filter element, flexing the fabric outwards
and effectively dislodging the dust layer.
In this way the pressure drop across the filter elements is kept at a virtually constant
level, enabling the Dalamatic to operate continuously, twenty-four hours a day.
Figure 15 Section through seal frame and two filter elements, showing principle of operation
b
Cleaning operation (intermittent)
a
Filtering operation (continuous)
Dust laden air
Recessed slots for
filter elements
Seal frame
C L E A N S I D E
D I R T Y S I D E
Airflow briefly
reversed, inflating bag
and dislodging dust
Dislodged dust layer
falling into container
Jet tube
injecting burst of compressed air
into filter element via the header
Additional air induced
by force of jet
Dust accumulating on
outer surface of bag
as the air penetrates
the fabric
Wire frame insert
Outlet header
Felt bag
Cleaned air
Sealing ring
Sealing flange
