﻿EVAPORATION OF FRUITS. 



29 



than over, the trays, and great differences in temperature and in the 

 drying rate between the upper and the lower portions of the tunnel 

 existed, with the result that it was necessary to shift the trays from 

 the upper runways to ]ower positions in order to hasten the drying. 

 These defects of the older tunnel driers are entirely remedied by the 

 expedient of giving the tunnel 3 feet of additional length and off- 

 setting, or banking, the trays. 



THE FURNACE ROOM. 



For a group of three tunnels heated by a single furnace, as is the 

 prevailing practice, the furnace room has a width equal to that of 



1 



PIPE 



3 Tv/i/Meif Aoove- /| 



K 



3 tunnels Above 



HBAreK 



3 Tl/NIVEU ABOVE\ 



/teATe/i 



\ 



AcArrat/f 



P 



st/ewre »*• 



/sm>.«? Afreet 



ArAVe &i/v 



A^OOS? /NO.INEO 



to oreNWe 





To o?fr/r 



I 'i 



ft A MP 



. *£ 



FIg. 12. — First-floor plan of the tunnel drier. 



the group of tunnels and a length 2 feet greater. This additional 2 

 feet of length is given at the lower end of the tunnels and permits 

 the furnace to be placed directly beneath the opening in the floor of 

 the central tunnel, as shown in Figures 11 and 12. The height to the 



