nt kilns is manifest where certain conditions require the
drying of numerous kinds as well as thicknesses of material at one and
the same time. This method permits of several short drying rooms or
apartments so that it is not necessary to mix hardwoods and softwoods,
or thick and thin material in the same kiln room.

In these small kilns the circulation is under perfect control, so that
the efficiency is equal to that of the more extensive plants, and will
readily appeal to manufacturers whose output calls for the prompt and
constant seasoning of a large variety of small stock, rather than a
large volume of material of uniform size and grade.

Apartment kilns are recommended for industries where conditions
require numerous kinds and thicknesses of material to be dried, such
as:

Furniture factories;
Piano factories;
Interior woodwork mills;
Planing mills; etc.

The "Pocket" Dry Kiln

"Pocket" dry kilns (see Fig. 37) are generally built in batteries of
several pockets. They have the tracks level and the lumber goes in and
out at the same end. Each drying room is entirely filled at one time,
the material is dried and then removed and the kiln again recharged.

The length of "Pocket" kilns ranges generally from 14 feet to about 32
feet.

The interior equipment for this type of dry kiln is arranged very
similiar to that used in the Apartment kiln. The heating or radiating
coils and steam spray jets extend the whole length of the drying room,
and are arranged for the use of either live or exhaust steam, as
desired.

Inasmuch as Pocket kilns have doors at one end only, this feature
eliminates a certain amount of door exposure, which conduces towards
economy in operation.

In operating Pocket kilns, woods of different texture and thickness
should be separated and placed in different drying rooms, and each
kiln adjusted and operated to accommodate the peculiarities of the
species and thickness of the material to be dried.

[Illustration: Fig. 37. Exterior View of Five Pocket Dry
Kilns, built in Two Batteries with the Front of each Set
facing the other, and a Transfer System between. They are
also equipped with the asbestos doors.]

Naturally, the more complex the conditions of manufacturing wood
products in any industry, the more difficult will be the proper
drying of same. Pocket kilns, are, therefore, recommended for
factories having several different