Improvements relating to the Utilizing of Heated Air in Drying Apparatus.
Year: 1892

page_text: Date of Application, 3rd Mar., 1892-Accepted, 9th Apr., 1892
Improvements relating to the Utilizing of Heated Air in Drying
Apparatus.
1, HEINRICH LEYDECKER of Glückstadt in Prussia, Germany, Manufacturer,
do hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement :-
This invention relates to drying by means of heated air, and the object of the
improvements is to more fully utilize the heat in the said air than: has heretofore
been done.
The heated air which acts direct on the materials to be dried must. in order to
give an active drying be left but a short time in contact with the said materials
since it is quickly saturated with moisture and loses its drying effect, and also
since a considerable ventilation or air current is required in the process of drying.
For these reasons the heated air has to be carried off while still at a comparatively
high temperature and a considerable amount of heat is thus wasted.
By however causing the heated air to pass through several separate drying
chambers (two or more) as hereinafter described, the heat of the said air may be
completely or almost completely utilized.
This is effected by causing the heated air, after it has been passed in contact
with the materials drying in the first chamber where it acts direct and becomes
saturated with moisture, into a second chamber or compartment where it however
does not come into direct contact with the materials drying therein but passes
through thin pipes or channels suitably arranged in this second chamber. The
actual drying air for this second chamber (the air which comes in contact with the
materials drying therein) passes into and through the chamber by natural or
artificial ventilation and is warmed by the heat from the aforesaid saturated heated
air passing through the pipes, so that this heated air is further utilized indirectly
in the second chamber in furtherance of the drying.
By similarly employing the air from the pipes in this second chamber to pass
through and warm a system of pipes or channels in a third chamber, and after that.
similarly in a fourth chamber, the heat in the air may be practically completely
utilized.
An apparatus constructed to utilize air on this principle is shown in the drawing
hereto annexed, in longitudinal section. Two chambers only are shown. A and
B represent the two chambers in which the materials to be dried are subjected to
currents of air. The heated dry air enters at e passes through the chamber A and
issues at after having in its passage become saturated with moisture from the
materials drying in the chamber A. At this hot moist air is drawn off by a
fan and passed into the end of the chamber B into the pipe in this chamber.
This pipe may be corrugated or shaped as shown, but it is preferable in practice
to use Hattened straight pipes or pipes corrugated or grooved longitudinally to
give large heating surface without hindrance to the current of air in the chamber B.
The moist air with still some heat left passes out at d into another similar pipe
system in a third chamber and thence also in the same manner into a fourth
chamber if desired.
t
In A the heated air acts direct on the materials, but in B and the subsequent
chambers it acts indirectly by heating the dry air entering at and passing
out at
The chambers A and B may be parts of the same apparatus or may be
distinct drying apparatus, provided the heated air used direct in one drying
space is used indirectly in another drying space.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed declare that what 1
claim is ;-
The improvements in the utilizing of heated air in drying apparatus consisting
in passing said air in direct contact with materials drying in a space or chamber,
and thence into a pipe system or equivalent for heating indirectly drying air in a
second space or chamber in which materials are dried.
Dated this 3rd day of March 1892.
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.