DUST CONTROL IN GRAIN ELEVATORS 5 
The suction system shown in Figure 1 was applied to the receiving 
belts at the unloading pits in one of the elevators visited. The 
space between the hoppers is inclosed, and a 6-inch suction connection 
is made near the apex of each triangular inclosure or near the point 
where the hoppers join. On each side of the belt, a canvas curtain, 
which drags on the inside of the upturned trough part of the belt, 
completely incloses the space above the receiving belts for the entire 
length of the hoppers. The dust-laden air, which rises from the 
belt when grain is being discharged from one of the hoppers, is thus 
confined and exhausted through the three 6-inch suction pipe con- 
nections. This application has been very effective in controlling the 
dust clouds at the receiving pits. As no induced air currents come in 
contact with the moving grain, only the dust clouds which rise from 
loading grain on a belt being finally drawn from the inclosure, this 
installation has had no effect on the grain weights. 
An installation (fig. 2) similar to that shown in Figure 1, but much 
simpler to install, can be adapted to a receiving-pit hopper of almost 
any type. A canvas curtain hangs down by the sides of the hoppers 
and drags on the inside of the receiving belt. The open spaces 
between the hoppers not covered by the belt are inclosed by either 
sheet metal or canvas, so that all the dust rising from the grain flowing 
on the belt is confined in the space between the belt and the hoppers. 
As a stream of air several inches deep follows a loaded conveyor belt 
at an average velocity of approximately one-fourth the belt speed, 
the space between the curtains is left open at the end where the 
belt first runs under the hoppers, making it possible for the air to 
flow in the direction of the belt and toward the other end of the 
inclosure. At the other end, however, the space between the cur- 
tains is inclosed by sheet metal and a curtain which drags on the 
grain. A rectangular suction hood of the proportions of the hood 
shown in Figure 32 is placed over the end curtain about 18 inches 
above the belt. Suction is supplied through a 7-inch pipe from the 
main duct of the dust-collecting fan system. 
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Fig. 2. — Proposed suction system for receiving pits 
