16 



BULLETIN 027, U. S. DEPARTMENT (XF AGRICULTURE. 



With steam at 50 cents a thousand pounds, which probably is as low as 

 could be obtained at the present prices for fuel and labor, the total cost 

 for heating the air during a season of, say, 50 eight-hour days would 

 be $50. 



Table IV shows the size and character of the equipment required 

 for exhaust and live steam, respectively. 



Table IV. — Comparison of the size and character of the respective equipments 

 required for exhaust and live steam in drying tomato seed. 



Equipment. 



Exhaust steam. 



Live steam. 











Probably greater 







Trap. 



Reduced pressure with re- 

 ducing valve is used. 

 Full steam pressure is used . 

















The cost of these installations will vary in every plant. It should 

 be noted, however, that if there is a small engine near the drier, all or 

 part of its exhaust steam may be piped to the radiator and allowed 

 to flow through it continuously without the use of a trap. 



Allowing 6 per cent for interest on the investment and 12 per cent 

 for depreciation, etc., an increased expenditure of as much as $275 

 for equipment for the use of exhaust steam over that for live steam 

 would be justified. If the cost of live steam is more than 50 cents a 

 thousand or the season longer than 50 days, even a greater expendi- 

 ture would be justified, with a possible increase in saving. 



EXTRACTING THE OIL FROM TOMATO SEED. 



Two methods are used for extracting oil from oleaginous seeds — 

 pressure and solvent extraction. 



The apparatus best suited for extracting oil by pressure is the 

 expeller type of press (fig. 10), which is admirably adapted for press- 

 ing seeds that contain from 18 to 20 per cent of oil. A description of 

 this press is unnecessary, since by its wide use in the oil-seed trade 

 it has already become more or less familiar. 



To test the effect of the expeller in the extraction of tomato-seed 

 oil, seed under varying conditions was passed through the machine, 

 as follows: One lot of seed was washed, dried, and handled in the 

 usual manner ; another lot was allowed to ferment in its own moisture 

 for about five days, since it was recognized that much of the seed 

 which would be assembled at the utilization centers would perhaps 

 be in varying stages of spoilage. One lot of seed which had heated in 

 storage because of previous insufficient drying was redried and passed 

 through the expeller. Another lot consisting of uncleaned fresh 

 seed with quite appreciable quantities of small pieces of skin attached 

 was dried and pressed. The results of the expeller tests of these 

 various lots of seed are shown in Table V. . 



