Dings Magnetic Group PERMANENT DEEP DRAW DRUM - Manual (Page 2)

Tighten the lower sections of the shaft clamps, and then slowly
lower the drum into them. When the shaft is supported in the lower
sections, bolt the upper sections loosely in place as show in Figure
3. Do not tighten the upper sections at this time, because they must
be loose to rotate the shaft while adjusting the magnet arc, as
explained next.
ADJUST MAGNET ARC - DRUM ONLY
The Deep Draw Drum is shipped with the internal magnet assembly
in the lowest or resting position as shown in Figure 4. After the
drum is mounted, the position of the internal magnet must be
adjusted to set the external magnetic arc in a correct operating
position.
Several possible arc positions are shown in Figures 5, 6 and 7. A
selected position for your application was predetermined before
shipment. It was based on the location of your feeder, and on other
application factors. Be sure you know which arc position was deter-
mined for you installation, before adjusting the internal magnet as
explained next.
Follow these steps when adjusting the magnet arc the first time:
1) Check bolts holding the upper sections on both shaft
clamps. The upper sections should be loose, but don’t
remove the bolts.
2) Mount the adjusting arm that was packed with the drum, on
either end of the drum shaft, in a horizontal or slightly below
horizontal position.
3) Use a come-along, winch or crane as shown in Figure 4
to raise the adjusting arm to a magnet position that was
predetermined for your installation. An arrow is stamped
on each end of the drum shaft. It indicates the center of
the magnet arc. The center is magnetically the strongest
location across the drum surface.
4) When the magnet position is correct, tighten bolts in the
upper sections on both shaft clamps while the adjusting arm
is held in position by the come-along or crane. If more
adjustment is needed, repeat steps 1 through4.
5) After a magnet position is set, remove the come-along or
crane, and also the adjusting arm.
It may be necessary later to reposition the arc slightly for peak
performance after material is run on the drum. Repeat the 5
adjusting steps for peak performance, but during Step 3, check if
the adjusting arm should be moved down slightly instead of up.
After the arc is finally set, consider leaving the adjusting arm on the
shaft, and welding a steel plate on the drum support structure to
act as a rest. This will prevent the internal magnet assembly from
slipping out of position, if the shaft clamp bolts accidentally loosen
from vibration.
FEED TO DRUM
Peak performance depends not only on the position of the magnet
arc. It also depends on these features: size of feed materials; dis-
tance or gap between the feeder and drum surface; rate of feed;
how constant the rate is kept; and whether the feeder trough is
made of a nonmagnetic type metal.
The feeder trough or plate must be made of a nonmagnetic metal
such as Series 300 stainless steel. If instead it’s made of common
carbon steel, the portion that is situated within the magnetic field
(inside the arc) will become magnetized. When this happens,
efficiency of magnetic separation goes down.
If your drum will be fed as in Figures 5 or 6, the gap between the
discharge edge of the feeder and the drum shell is important. It must
be wide enough to allow all nonmagnetics in the feed to fall through
while the drum is operating. It must not be too wide which can
cause a loss of magnetic material.
The maximum width of the gap depends on the magnetic strength
of the drum which is a function of diameter. No specific gap
dimension is included in this bulletin. The gap for your installation
was predetermined at the time of drum selection. Be sure you
know what the determination was.
If your drum will be fed as in Figure 7, the distance between the dis-
charge edge of the feeder trough or plate, and the shell below,
should be as short as possible. Feed material must not be allowed
to drop more than a few inches against the shell, to avoid denting
the shell. A dent can damage the internal magnet assembly. If the
feeder has to be higher above the drum, install a nonmagnetic stain-
less steel chute at an angle that will allow the feed to slide down to
the shell.