The vacuum can use the same
compressor as the Air Knife, as long as the compressor size is not less
than 100 psi/175 cfm. Nozzles at the inside bottom of the suction tube
direct the air stream upward, creating a vacuum at the tube entrance
so as to suck crumbled soil, gravel (< 2 3/4 inch), and/or water
from the excavation. The materials travel up the tube, and are deposited
at/near the end of a 3.5" I.D. or 4" I.D. flexible discharge
hose. The diameter and length of the discharge hose are determined by
a combination of compressor rating and customer preference.
The vacuum is held with two
hands, at a small angle to vertical. The angle assures that sufficient
air is drawn into the suction to draw material into the barrel. There
is an integral air gage on the Air Vacuum. By observing the gage pressure,
the operator can determine if pressure is adequate at the tool. Normal
operating pressure will be less than the Air Knife, Air pressure being
not as critical for the Air Vacuum as it is for the Air Knife.
The operator can wear normal
work clothes, however many operators prefer to wear coveralls. Ear,
eye and hard hat protection is required. A face shield is desirable.
Other normal safety precautions associated with compressed air must
also be employed.