Figure 8-4.-Pugmill
plant. The feeder may be charged by a clamshell or
front-end loader. Aggregate feeder units should have
controls that can beset and secured to produce a uniform
flow of aggregate to the cold elevator.
For a uniform OUTPUT from the asphalt plant,
INPUT must be accurately measured. The importance
of feeding the exact amounts of each size aggregate into
the dryer at the correct rate of flow cannot be
overemphasized.
The following conditions ensure a uniform flow of
aggregate sizes:
l Correct sizes of aggregate in stockpiles.
l No intermixing of stockpiles.
. Accurately calibrated, set, and secured feeder
gates.
. Gates kept free of obstruction.
l No excessive arching in the fine aggregates.
Arching can be minimized by using rectangular (rather
than square) openings above the feeders or placing
Figure 8-5.-Aggregate storage and cold-feed system.
8-3
