All dust collectors include a hopper that collects the captured dust. These hoppers are not designed for storage of the dust, however. They are there for the dust to collect until it passes out of the dust collector through an airlock, such as a rotary valve, double-dump valve, trickle valve, etc. Adequate discharge intervals are important. If enough dust builds up in the hopper, then the dust will get re-entrained into the air. This could cause a few issues.