Determining Main Line Duct Size; Determining Branch Line Duct Size; Drop Downs - Grizzly G0443 Owner's Manual

Determining Main Line Duct Size

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.
Jointer
Planer/
Moulder
395
Miter
5"
Saw
98
Shaper Table Saw
figure 41. Main line size labeled on sketch.

Determining branch Line Duct Size

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.
-28-
Sander
395 790
6" 7"
Dust
Collector
Planer
Planer/
395
Moulder
4"
5"
Miter 4"
Saw
98
4"
220
Shaper Table Saw
figure 42. Branch line duct sizes labeled.

Drop Downs

plan all the drop downs for each machine with
blast gates, as shown in the figure below.
Rigid Pipe
(Main Line)
Y Branch
Clamp
Flex Pipe
To Planer
figure 43. drop down setup.
Model g0443 (Mfg. since 11/09)
Jointer Sander
790
395
4" 6"
6" 7"
Dust
Collector
4" 5"
395
614
Planer
Elbow
Rigid Pipe
Blast Gate