DUST CONTROL, IN GEAIN 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. Repeatedly, 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 oats 
Static 
head 
Total 
head 
Velocity- 
head 
Velocity- 
head 
Velocity 
Grain 
lifted 
Remarks 
In. oil 
In. oil 
In. oil 
In. water 
Ft. per rain. 
Per cent 
-0. 135 
-0. 055 
0.080 
0.066 
1,070 
100 
-.120 
-.050 
.070 
.058 
1,004 
95 
Only heavy grains left. 
-.100 
-.045 
.055 
.046 
894 
48 
-.090 
-.040 
.050 
.042 
854 
6 
-.075 
-.035 
.040 
.033 
757 
3 
Only very light grains 
lifted. 
-.070 
-.032 
.038 
.032 
745 
1 
-.058 
-.025 
.033 
.027 
685 

Air data. — Dry bulb, 94° F.; wet bulb, 77° F.; barometric pressure, 29.25 inches of mercury; vapor 
pressure (e), 0.732. 
Sample calculation of air velocity.— F=1096.5-«/— 
h= 0.066 
„„ , oo^(^-0-378e) , „„, r ,, 29.25- (0.378X0.732) \^ 
w = 1.3245X m+t -1.3245X ^^^ -0.06932. 
Vo 
^oSr 1070 ' 
Table 4. — Air velocity for lifting corn 
Static 
Total 
Velocity 
Velocity 
Velocity 
Grain 
head 
head 
head 
head 
lifted 
In. oil 
In. oil 
In. oil 
In. water 
Ft. per min. 
Per cent 
-0. 485 
-0. 190 
0.295 
0.245 
2,062 
100 
-.420 
-.175 
.245 
.203 
1,877 
98 
-. 350 
-.140 
.210 
.174 
1,737 
92 
-.285 
-.125 
.160 
.133 
1,520 
62 
-.245 
-.115 
.130 
.108 
1,369 
25 
-.215 
-.100 
.115 
.096 
1,291 
5 
-.195 
-.095 
.100 
.083 
1, 200 
2 
-.170 
-.090 
.080 
.066 
1,070 

Air data. — Dry bulb, 94° F.; wet bulb, 74° F.; barometric pressure, 29.5 inches of mercury; calculated air 
weight, 0.06944 pound per cubic foot. 
Table 5. — Air velocity for lifting wheat 
Static 
Total 
Velocity 
Velocity 
Velocity 
Grain 
head 
head 
head 
head 
lifted 
In. oil 
In. oil 
In. oil 
In. water 
Ft. per min. 
Per cent 
-0.230 
-0. 095 
0.135 
0.112 
1,395 
100 
-.205 
-. 085 
.120 
.100 
1,318 
90 
-.175 
-.075 
.100 
.083 
1,200 
16 
-.145 
-.065 
.080 
.066 
1,070 
4 
-.130 
-.055 
.075 
.062 
1,037 
1 
-.125 
-.058 
.067 
.056 
986 

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. 
