﻿52 



BULLETIlSr 1374, TJ. S. DEPARTMENT OP 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 

 faUing 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 boUworm, 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 macliine, 42 revolutions per minute. Time of exposure, 1 minute 5 seconds. Steam admitted 



into two upper conveyors only] 



Test 



No. 



1 

 Number | Seed tempera- 

 of larvae i ture on 

 in tests discharge 



Larvae 

 killed 



Test 

 No. 



Number 

 of larvae 

 in tests 



Seed tempera- 

 ture on 

 discharge 



Larvae 

 kiUed 







°F. 



Per cent 







"F. 



Per cent 



18 



6 



136 -141 



100 



45 



56 



145 -149 



100 



47 



65 



143 -137 



100 



42 



69 



146 -145M 



100 



41 



10 



140 -138 



80 



34 



42 



151 -1453^ 



100 



19 



7 



141 -140 



100 



11 



14 



146 



100 



40 



17 



144J^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 



148H 



100 



43 



47 



145H-141 



100 



21 



16 



149 -150 



100 



15 



7 



145^-1413^ 



100 



12 



4 



150 



100 



16 



5 



UIVt-UQ 



100 



24 



54 



150 



100 



14 



8 



142 



100 



28 



S4 



150 -152 



100 



48 



43 



142 J^ 



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^ 



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 



' The only living larva found in this sample was crawling on the treated sample 



and probably had not passed through the machine. 



