678 Journal of Agriculture, Victoria. [10 ISTov.. 1917. 



of any given truck do not dry at eqnal rates, necessitating overdrying of 

 the lower trays or transfer of the upper ones to another truck, and even 

 more objectionable in that the operator cannot learn how the fruit 

 toward the middle of the tunnel is drying except by rolling out all the 

 trucks until that which he desires to inspect is reached. Consequently, 

 trucks are no longer generally employed in tunnel evaporators, and have 

 been replaced by an arrangement which permits individual trays to be 

 moved with little diiReulty. To build this, the individual tunnels of a 

 group or series are separated one from the other by partitions or, at 

 least, by a framing of 2 x 4 studs. To these partitions or to the studs 

 are nailed a series of cleats, usually made of I or 1 inch strips, 2 inches 

 wide, nailed flat, extending from end to end of the tunnel parallel with 

 the inclined floor, and placed at equal distances, preferably 4 inches 

 from centre to centre, apart.. These cleats form a series of tracks, one 

 above the other, which support the trays upon which the fruit is spread, 

 and the tunnel is filled by pushing the trays in one after another at the 

 upper end of the tunnel, and moving them along the tracks until all are 

 loaded. The heated air is admitted at the lower end of the tunnel, from 

 a furnace placed in the room beneath, rises throiigh the successive series 

 of trays, and passes off, loaded with moisture, through a ventilator shaft 

 at the opposite higher end. Steady air movement is secured by an 

 arrangement of air intakes in the furnace room, essentially identical 

 with that already deseribed for the kiln evaporator. 



All that has been said in the preceding pages as to the relative merits 

 of various building materials for constructing kiln evaporators applies 

 equally well when the plant is to be of the tunnel type. The advantages 

 and economy of permanent fire-proof construction are the' same, as is the 

 necessity for having the portion of the building in which the actual 

 drying goes on as nearly air-tight as possible, and with the loss of heat 

 by radiation reduced to the lowest possible minimum. 



The building must consist of two portions, a portion in which the 

 preparation of fruit for drying is carried on and in which -the dried 

 fruit, ti'ays not in use, and fruit awaiting preparation can be stored, 

 and a second portion in which the actual drying is accomplished. In 

 the first portion or preparation room there will be needed the same 

 equipment described in connexion with kiln evaporators, and its arrange- 

 ment may conveniently be essentially that shown by the plans for such 

 plants. If berries or prunes are to be dried in any quantity, there will 

 be needed space on the ground floor of the building for spreading tables 

 and for storage of trays and of boxes of fruit brought in from the 

 orchards. ISTotwithstanding these facts, the plans of two-kiln and four- 

 kiln evaporator buildings may very well serve as suggestions for build- 

 ings for tunnel evaporators. Tunnels of a given capacity occupy less 

 than one-half as much floor space as kilns of the same capacity. The 

 tunnels may be constructed in a portion of the space given to kilns in 

 the jjlans, and the remaining space becomes available for work tables, 

 storage of fruit, trays, &c. The plans of kiln plants have purposely been 

 so designed that when tunnels instead of kilns are placed in them, the 

 paring tables, bleacher, apple bins, and slicer will be as little in the way 

 as possible when the building is used for drying berries or prunes. It is 

 believed, therefore, that these drawings and suggestions give as much aid 

 as possible in a publication of this general character since each builder 

 of a tunnel evaporator must work out the details of the plan for a 



