320.1 Inlet Duct Design
When you run ducting to your collector, it is important to follow these guidelines.
1. The straight length of duct entering the inlet should be a minimum of 2 duct diameters.
2. The transition angle from the duct to the inlet flange should be a minimum of 45°.
In figure 320.8, the “RECOMMENDED” design shows a vertical section of duct, a 90° elbow and a
horizontal length of a least 2 duct diameters before entering the inlet. The air direction will cause the
dust to be evenly distributed to the filters. In the “NOT RECOMMENDED” design, the duct enters the
inlet at an angle. The air direction will force dust already in the hopper (previously pulsed off the
filters), to be re-entrained into the air stream.
In figure 320.9, the “RECOMMENDED” design shows a straight section of duct that is at least 2 duct
diameters long, before entering the inlet. The air direction will cause the dust to be evenly distributed
to all of the filters in the collector. In the “NOT RECOMMENDED” design, the duct is not long enough
to allow the air to straighten out before entering the inlet. The air direction will force the dust to one
side of the collector, resulting in uneven dust loading on the filters.
15
38
"
2"
Figure 320.6
TOP OUTLET FLANGE
(FULL PANEL)
40"
9 SPA @ 4" =36"
3/8-16 UNC
2"
1"
38"
40"
9
S
P
A
@
4"
= 36
"
38"
2"
Figure 320.7
TOP OUTLET FLANGE
(HALF PANEL)
19"
3-1/2"
3-1/2"
3 @ 4"
= 12"
3/8-16 UNC
17"
1"
2"
DUCT
DIA.
DUCT
DIA.
TRANSITION
INLET
DUST
PARTICLES
DUST
PARTICLES
RECOMMENDED
NOT RECOMMENDED
Figure 320.8 - Side View
60°
MIN
.
TR
AN
SIT
ION
SLO
PE
DUCT LENGTH
MIN 2X DIAMETER
