Electronics 590-24 - Manual (Page 8)

8
Recommendations:
1)Use pipe unions to easily align or remove the MagnaValve. With the provided manual
shut-off valve there is no need to drain the pressure pot of shot to clear contaminants
that have lodged in the MagnaValve
2)If a negative pressure exists in the shot hopper (i.e. when a pneumatic reclaim system
is used to recycle the shot), then allow about 6-inches (15 cm) minimum distance be-
tween the top of the MagnaValve and the bottom of the shot hopper. This column of
shot will act as a dam to isolate the pressure differences and prevent air and shot
from being sucked back up into the hopper.
3)The aspiration air inlet should be a minimum of 0.5 inch diameter. Smaller openings will
permit a very large negative pressure that may draw shot through the MagnaValve
and cause erratic operation. The nozzle must have adequate aspiration air volume to
convey the shot through the blast hose. The inlet can be as large as 1.25 inch and a
screen should be installed to prevent the ingestion of debris into the air stream.
4)The venturi suction must be adequate to convey (lift) the shot up to the nozzle level.
This suction may draw shot through the MagnaValve. The remedy for this is a) in-
crease the aspiration inlet size to reduce the negative pressure b) maintain a large
“head” of shot above the MagnaValve to isolate the pressure difference c) relocate the
MagnaValve above the nozzle level.
5)Install a vacuum gage (negative pressure gage) temporarily to the aspiration inlet to
measure the suction of the nozzle. This gage can take two types of measurements,
static and dynamic. The static reading is the largest reading and measured by denying
any aspiration air. (Note: in some cases the negative pressure may be sufficient to
draw shot through the MagnaValve. Do not operate the system with this gage in
place, as this will prevent introduction of aspiration air needed to convey the shot to
the nozzle.) The second type of measurement, dynamic, is performed with the gage
installed and does not alter the aspiration air volume. This type of measurement does
not interfere with system performance and can be left in place permanently if desired.