DUST CONTROL IX GRAIN ELEVATORS 
39 
velocity was reduced slightly by opening the slide door near the 
fan. After the fan had run for about five minutes with the velocity 
at the hood constant, the air velocity readings were taken and the 
fan was shut down. Kepeatedly, in this manner, the velocity of 
the air was slightly reduced, and readings were taken until no kernels 
of grain were lifted from the screen. Particular care was taken to 
obtain the highest velocity which would not lift the grain. The 
results of these experiments are given in Tables 3, 4, and 5. 
Table 3. — Air velocity for lifting oai.-i 
Static 
Total 
Velocity 
Velocit y 
Grain 
Ren 
head 
head 
head 
lifted 
In. water 
In. water 
In. water 
Ft. per min. 
Per cent 
-0. 135 
-0.055 
0.080 
1,178 
100 
-.120 
-.050 
.070 
1,102 
95 
Only heavy grains lefr. 
-.100 
-.045 
.055 
978 
48 
-.090 
-.040 
.050 
932 
6 
-.075 
-.035 
.040 
834 
3 
Only very light grains 
lifted. 
-.070 
-.032 
.038 
812 
1 
-. 05S 
-.025 
.033 

.fir data— Dry bulb, 94° ¥.: -ret bulb, 77° F.; barometric pressure, 29.25 inches of mercury; vapor 
pressure (e), 0.732. 
Sample calculation of air velocity — V= 1096.5-/— 
V w 
A =0.080 
r=1096.5-/°^_=ll78. 
V 0.06932 
Table 4. — Air velocity for lifting corn 
Static- 
Total 
Velocity 
Velocity 
Grain 
head 
head 
head 
lifted 
In. wafer 
In. water 
In. water 
Ft. per min. 
Per cent 
-0.485 
-0.190 
0.295 
2,262 
100 
-.420 
-. 175 
.245 
2,062 
98 
-.350 
-.140 
.210 
1,908 
92 
-.285 
-. 125 
.160 
1,665 
62 
-.245 
-.115 
.130 
1,503 
25 
-.215 
-.100 
.115 
1.412 
- 
-.195 
-.095 
.100 
1.317 
2 
-.170 
-.090 
.080 
1,178 

Air data.— Dry bulb, 94° F.; wet bulb, 74 c 
■weight, 0.06944 pound per cubic foot. 
F.; barometric pressure, 29.5 inches of mercury: calculated air 
Table 
5. — Air 
velocity for lifting wheat 
Static 
Total 
Velocity 
Velocity 
Grain 
head 
head 
head 
lifted 
In. water 
In. water 
Ft. per min. 
Per cent 
-0. 230 
-0.095 
0.135 
1,532 
100 
-.205 
-.085 
.120 
1.443 
90 
-.175 
-.075 
.100 
1,318 
16 
-.145 
-.065 
.080 
1. 17S 
4 
-. 130 
—.055 
.075 
1. 142 
1 
-.»! 
-.052 
.068 
Air data— Dry bulb. 94° F.: wet bulb, 78° F.; barometric pressure, 29.25 inches of mercury; calculated 
air weight, 0.06928 pound per cubic foot. 
