920 
well as up through it, the claim being 
made that this movement of air induces 
a more rapid drying of the fruit than 
in ordinary methods of construction. 
Kiln Evaporators 
Of the types having sufficient capacity 
for handling apples from large com- 
mercial orchards, the kiln evaporator is 
by far the most important. 
While the principles of construction 
of the different evaporators of this type 
are similar in all cases, the details and 
the arrangement of the appliances are 
endlessly varied. 
In constructing kilns the same gen- 
eral principles are followed, whether the 
evaporator is a small one with only a 
&. 
Fig 1. Fuirst-floor Plan of an DBDvaporato1, 
showing the arrangement of the principal de- 
tails A, doors, 3B, windows: C, paring 
table, D, bleacher; @, stairs; F, chimney, 
G, furnace; H, pipes. 
single kiln or an extensive establish- 
ment having several of them. The most 
satisfactory size of kiln, all things con- 
sidered, is about 20 feet square. This is 
a convenient size to fill, so far as the 
preparation of the fruit is concerned; 
the heat can be well regulated, made suf- 
ficiently intense for the purpose desired, 
and evenly distributed, so that the fruit 
will dry uniformly, and for various mi- 
nor reasons a kiln of this size is a desir- 
able “unit” in the construction of evap- 
orators of this type. 
A. kiln consists essentially of a floor 
made of slats and placed over a furnace 
room or over a system of steam pipes. 
The floor is usually built from 10 to 12 
feet above the floor of the furnace room. 
Provision should be made for regulating 
the heat by means of small openings at 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
the base of the walls, communicating 
with the outside, which can be opened 
or closed as desired The inflow of cold 
air can thus be regulated. Such control 
is especially desirable in windy weather. 
While many evaporators are constructed 
without special provision of this kind, it 
is an important point to have such open- 
ings, particularly if the walls are brick 
or otherwise made very tight, so that 
there is but little circulation of air. 
If the evaporator is a frame building, 
the walls of the furnace room may well 
be plastered or covered with asbestos 
paper to lessen the danger of fire, which 
may otherwise be great, because of the 
intense heat generated within them. 
If the walls, at least the portion below 
the kiln floor, are double, with an air 
space between the two sides, the insula- 
tion will be more perfect than if they 
are solid or of only a single thickness, 
thus best conserving the heat and in- 
creasing the efficiency of the plant. The 
height of the walls of the kiln above 
the drying floor should be sufficient to 
permit an attendant to work on the floor 
conveniently and with comfort. 
Some means for the escape of the air 
laden with moisture from the fruit is 
necessary. This may be provided for by 
means of an opening in the roof, or a 
cupola-like ventilator may be built, the 
sides of which should consist of slats 
placed so that they overlap one another 
as in an ordinary window blind. An- 
other form of ventilator is in the form 
of a tower about 3 feet square and ex- 
tending 8 or 10 feet above the roof, 
which is sufficiently high to cause more 
or less draft, and hence augments the 
circulation of hot air through the fruit. 
Fig 2 Section of a Kiln Floor, Showing the 
Method of Construction. 
