30 CIRCULAR NO. 116, BUREAU OF PLANT INDUSTRY. 



WORK IN THE YEAR 1910. 



Test runs were made during the season of 1910 on each crop of 

 alfalfa, and the results obtained were of much value. It became 

 evident that the capacity of the plant would have to be increased 

 before artificial curing would become a success. An important limit- 

 ing factor in determining the capacity of the kiln was found to be 

 that of the circulation of the air. which was too slow and not under 

 proper control. 



WORK IN THE YEAR 1911. 



By the installation of power fans and additional steam coils the 

 capacity of the plant was greatly increased, and a second important 

 limiting factor was developed, namely, that of the manner of feed- 

 ing. It was discovered that efficiency depended largely upon the 

 evenness of distribution of the stream of hay in its progress through 

 the apparatus. Whether feeding light or heavy, if hay was placed 

 on the elevator in knots or twists it would not cure. The importance 

 of a mechanical feeder thus became manifest. 



A third limiting factor was found to be due to the improper cir- 

 culation of the air. and a method was devised whereby the heated 

 air was forced straight up through the hay. The necessary mechan- 

 ical changes were effected, but not in time to be tested during the 

 season of 1911. 



WORK IN THE YEAR 1912. 



Tests of a mechanical feeder and of the improved method of air 

 circulation were made during the season of 1912. The new devices 

 gave satisfaction with cowpea hay as well as with alfalfa. The 

 mechanical feeder tore apart the wisps and lumps of hay and dropped 

 them evenly on the feed elevator. The capacity of this small experi- 

 mental plant was found to be 653 pounds of cured hay per hour 

 when working with freshly cut alfalfa. The limiting factors were 

 found to be those of faulty installation, mainly manifest in the tem- 

 porary character of the building used and in the types of engine 

 and boilers, which were poorly adapted for the purpose. 



PROPOSED WORK FOR 1913. 



The series of experiments thus far conducted shows a gradual and 

 steady improvement in the system, tending to lower the cost of curing 

 and to increase the capacity of the kiln. Even with the present 

 capacity it is believed that a large plant of the same type would prove 

 profitable where the hay is to be made into meal. 



There is every indication that larger circulation, better boiler pres- 

 sure, and much heavier feeding, combined with somewhat slower run- 

 [Cir. 116] 



