Model G0850 (Mfd. Since 01/19)
-31-
The general rule of thumb for a main line duct is
that the velocity of the airflow must not fall below
3500 FPM.
For small/medium sized shops, using the inlet size
of the dust collector as the main line duct size
will usually keep the air velocity above 3500 FPM
and, depending on your system, will allow you to
keep multiple branches open at one time.
Mark your drawing, as shown in the figure below,
but using the inlet size for your dust collector as
the main line.
Figure 61. Main line size labeled on sketch.
400
400
600
800
400
250
100
Dust
Collector
5"
6"
7"
Table Saw
Planer/
Moulder
Miter
Saw
Jointer
Sander
Planer
Shaper
The general rule of thumb for a branch line duct is
that the velocity of the airflow must not fall below
4000 FPM.
For small/medium sized shops, using the dust
port size from the machine as the branch line duct
size will achieve the correct velocity in most appli-
cations. However, if the dust port on the machine
is smaller than 4", make the branch line 4" and
neck the line down right before the dust port.
Note: Systems with powerful dust collectors work
better if multiple blast gates are left open. This
also allows you to run two machines at once.
Experiment with different combinations of blast
gates open/closed to find the best results for your
system.
Write your determined branch line sizes on your
drawing, as shown in the following figure.
Determining Branch Line Duct Size
Figure 62. Branch line duct sizes labeled.
400
400
600
800
400
250
100
4"
4"
4"
6"
4"
4"
5"
5"
6"
7"
Table Saw
Miter
Saw
Jointer
Sander
Planer
Shaper
Planer/
Moulder
Dust
Collector
Plan the drop downs for each machine, using
blast gates wherever possible to control airflow.
Planning Drop Downs
To Planer
Blast Gate
Flexible Duct
Rigid Duct
Rigid Duct
(Main Line)
Elbow
Clamp
Y Branch
Figure 63. Drop-down setup.
Determining Main Line Duct Size
Summary of Contents for G0850
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