52 
BULLETIN 1374, U. S. DEPARTMENT OF AGRICULTURE 
steam is injected directly into the moving seed mass in the con- 
veyor. A regulating valve controls the quantity of steam passing 
into the conveyors, and other valves serve to cut off the steam from 
any of the conveyors altogether, if desired. A thermometer with 
the bulb fixed near the discharge end of the machine records the 
temperature of the seed as it passes out of the machine. 
In testing this machine it was learned that the seed is very un- 
evenly heated while passing over the perforated pipes. Some seeds 
are hit directly by a jet of steam; others pass entirely through the 
conveyor without being hit directly. But at the same time the 
vapor is thoroughly mixed with the seed. When the seed is run 
directly from a heated conveyor into a sack, the temperature im- 
mediately rises very high, but soon drops again. The first high 
reading evidently is due to the vapor and the hot outside walls of 
the seed. When the seed is left in bulk for a short time, this heat 
penetrates to the inside of the individual seeds, causing a lower but 
more even temperature throughout the seed mass, and a consequent 
falling of the temperature. If this is true, it explains the fact that 
treatment in a single conveyor, even though giving a temperature 
in a sacked sample high enough to kill the pink bollworm, fails to 
kill if the seed is immediately cooled. 
A number of series of tests were conducted with this machine 
operated at different speeds and steam pressures, and with steam 
injected into different conveyors. The procedure followed was 
similar to that with the dry-heat machine. The machine was fed by 
hand. Samples for examination were caught on a screen and imme- 
diately cooled, the double seed picked out and examined. Between 
each two samples for examination, a sample for temperature readings 
was taken. Thus in the records, with a few exceptions, two tempera- 
tures are given for each test, as in the tests with the other machine. 
The results of these tests are given in Table 44. 
Table 44. — Results of treatment of cottonseed in live-steam disinfecting machine 
SERIES 1 
[Speed of machine, 42 revolutions per minute. Time of exposure, 1 minute 5 seconds. Steam admitted 
into two upper conveyors only] 
Test 
No. 
Number 
of larvae 
in tests 
Seed tempera- 
ture on 
discharge 
Larvae 
killed 
Test 
No. 
Number 
of larvae 
in tests 
Seed tempera- 
ture on 
discharge 
Larvae 
killed 
°F. 
Per cent 
°F. 
Per cent 
18 
6 
136 -141 
100 
45 
56 
145 -149 
100 
47 
65 
143 -137 
100 
42 
69 
146 -145H 
100 
41 
10 
140 -138 
80 
34 
42 
151 -145H 
100 
19 
7 
141 -140 
100 
11 
14 
146 
100 
40 
17 
144^-140 
100 
23 
22 
148 
100 
37 
11 
141 -143 
100 
25 
55 
148 
100 
44 
44 
141 -145 
100 
22 
20 
150 -148 
100 
36 
13 
145 -141 
100 
13 
6 
148^ 
100 | 
43 
47 
145J4-141 
100 
21 
16 
149 -150 
100 1 
15 
7 
1453^-141^ 
100 
12 
4 
150 
100 | 
16 
5 
1413^-146 
100 
24 
54 
150 
100 
14 
8 
142 
100 
28 
54 
150 -152 
100 
48 
43 
142M 
197.6 
27 
41 
154 -150 
100 
38 
15 
143 -144 
100 
33 
33 
152 -151 
100 
.46 
38 
149 -143 
100 
30 
48 
154 -151 
100 
20 
18 
144 
100 
31 
42 
151 -155 
100 
39 
13 
144 -1443/3 
100 
29 
56 
152 -154 
100 
26 
32 
144 -154 
100 
32 
46 
155 -152 
100 
35 
14 
148 -145 
100 
17 
5 
153 -154 
100 
i The only living larva found in this sample was crawling on the treated sample 
and probably had not passed through the machine. 
