Improvements in Apparatus for Employing Heated Air in Drying or Baking Vegetable or other Substances.
Year: 1885

page_text: Improvements in Apparatus for Employing Heated Air in
Drying or Baking Vegetable or other Substances.
I SAMUEL CLELAND DAVIDSON of Belfast in the County of Antrim, Ireland,
Merchant do hereby declare the nature of my invention for IMPROVEMENTS IN
APPARATUS FOR EMPLOYING HEATED AIR IN DRYING OR BAKING VEGETABLE OR
OTHER SUBSTANCES" to be as follows:-
In a former Provisional Specification dated 29th July 1884 No 12708 I described
an apparatus for employing heated air in drying or baking, which consists essen-
tially of a vertical air duct containing sloping shelves or hoppers with intermediate
air passages and connected at the base with the hot air supply, and at the top with
a horizontal drying flue, along the open top of which trays containing the material
to be dried are so arranged on slides, that when in work they form the top cover
of this flue and move through from end to end of it one in front of another, while
the hot air ascends through them and escapes from their upper surface carrying the
moisture away with it and for brevity I hereinafter refer to the Specification as
my "previous specification."
My present invention consists in constructing the apparatus so that the hopper
shoots and their intermediate air passages are partly in the vertical air duct and
partly in the horizontal flue instead of being entirely contained in the air duct,
and the air duct is preferably connected to the centre of the horizontal flue by
which arrangement the hot air as it flows into the horizontal flue is deflected
towards both ends of it by the hopper shoots therein contained and thus a more
equal distribution of the hot air to all the trays is effected.
My invention further consists in so arranging or combining the horizontal flue,
vertical air duct, hopper shoots and intermediate air passages, that the outward
form of the apparatus resembles the letter V truncated thus \/. A rectangular base
is thereby formed on which the apparatus stands and it is made open in the centre
to admit the hot air supply from below. The sides of the apparatus are vertical
and what may be called the ends are sloping. The hopper shelves with their inter-
mediate air passages are arranged over the open base so that any fine tea or other
material falling upon them from the trays when in work slides down along them,
and falls out through openings at either side of the base. The ends of the appa-
ratus also form sloping hopper shoots and any material falling on them in like
manner slides down and falls out through the same openings and thereby obviates

page_text: all risk of its getting burnt. The top of the apparatus is open and the trays slide
along and cover it over when in work in the same manner as described for the
horizontal flue of my previous specification.
Instead of the longitudinal sides of the apparatus being vertical as above
described they (as well as the ends) may be made sloping; the apparatus would
then resemble in form an inverted truncated pyramid.
The apparatus may be made sufficiently wide to accomodate two or more lines
of trays side by side and these lines of trays may be single or grouped as two or
more lines superimposed. The trays when superimposed may all be moved along
the lines in one direction, the damp material being fed in at one end and taken out
dry at the opposite end, but the working of them which I preferably employ is to
feed them in on the top line damp, push them along top slide to opposite end, then
transfer them to lower line and push them back along it to the end they started
from and thereat be withdrawn when quite.dry. In this way the driest tray has
always a fresh wet one over top of it, while at opposite end the half dry tray has a
half dry one over top of it and the intermediate trays on the lower slide in progres-
sive stages of dryness have correspondingly damp trays over them, and by this
arrangement each pair of superimposed trays, along the whole length of the flue,
present to the hot air passing up through them the equivalent in moisture of one
fresh wet tray between them, and in this way while a continuous feed and delivery
of material is accomplished a perfectly equal distribution of damp material is
invariably maintained from end to end of the apparatus, and consequently this
arrangement allows scarcely any of the hot air to escape unutilized and is therefore
most economical in its operation.

page_text: Drying or Baking Vegetable or other Substances.
I SAMUEL CLELAND DAVIDSON, of Belfast in the County of Antrim, Ireland,
Merchant 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 :-
In the Specification of former Letters Patent granted to me and dated the
29th day of July 1884 (N° 12,708) I described an apparatus for employing
heated air in drying or baking which consists essentially of a vertical air duct
containing sloping shelves or hoppers with intermediate air passages and connected
at the base with the hot air supply, and at the top with a horizontal drying flue,
along the open top of which trays containing the material to be dried are so.
arranged on slides that when in work they form the top cover of this flue, and.
move through from end to end of it, one in front of another, while the hot air
ascends through them, and escapes from their upper surface carrying the moisture
away with it, and this Specification is hereinafter referred to as my "previous
specification."
The present invention consists in constructing the apparatus so that the hopper
shoots and their intermediate air. passages are partly in the horizontal flue, instead.
of being entirely contained in the air duct, and the air duct is preferably connected
below the centre of the horizontal flue, by which arrangement the hot air, as it
flows into the air flue below the trays is deflected to both ends of the horizontal
flue, as the hopper shoots also act as deflecting plates, and thus a more equal
distribution of hot air to all the trays is effected.
The invention further consists in so arranging and combining the horizontal flue,
vertical air duct, hopper shoots and intermediate air passages that the outward form
of the apparatus resembles the letter V truncated thus \/-a rectangular base is
thereby formed on which the apparatus stands, and it is made open in the centre,
to admit the hot air supply from below.
The longitudinal sides are vertical and what may be called the ends are sloping.
The hopper shelves with their intermediate air passages, are arranged over the
open base so that any fine tea or other material falling upon them from the trays
when in work, slides down along them, and falls out through openings at either
side of the base. The ends of the apparatus also form sloping hopper shoots and
any material falling on them, in like manner slides down and falls out through
the same openings and thereby obviates all risk of its getting burnt by being
retained inside.
The top of the apparatus is open, and the trays slide along and cover it over
when in work, in the same manner as described for the horizontal flue of my
previous Specification.
Instead of the longitudinal sides of the apparatus being vertical as above described,
they, as well as the ends may be made sloping. The apparatus would then resemble
in form an inverted truncated pyramid. The apparatus may be made sufficiently
wide, to accommodate two or more lines of trays side by side, and these lines of
trays may be single or grouped as two or more lines superimposed.

page_text: The trays when superimposed may all be moved along the lines in one direction,
the damp material being fed in at one end, and taken out at the opposite end, but
the working of them which I preferably employ is to feed them in on the top line
damp, push them along the top slide to the opposite end, then transfer them to the
lower line, and push them back along it to the end they started from, and thereat
be withdrawn when quite dry (or baked). In this way the driest tray has always
a fresh wet one over the top of it, while at the opposite end, the half dry tray
has a half dry one over the top of it, and the intermediate trays on the lower slide
in progressive stages have correspondingly damp trays over them, and by this
arrangement each pair of superimposed trays along the whole length of the flue,
present to the hot air passing up through them the equivalent in moisture, of one
fresh wet tray between them, and, in this way while a continuous feed and delivery
of material is accomplished a perfectly equal distribution of damp material is
invariably maintained from end to end of the apparatus and consequently this
arrangement allows scarcely any of the hot air to escape unutilized and is therefore
most economical in its operation.
The accompanying drawings represent the apparatus as constructed in accordance
with the present invention. Figure 1 represents the apparatus when constructed
in the shape of the letter T, that is with the sides of the upward air duct all
parallel and vertical. Figure 2 shows the vertical air duct with the upper half of
the end shoots sloping outwards; and Figure 3 (which is drawn to a smaller scale)
is the truncated V form. The letters employed to identify the various parts are
the same for the similar and corresponding parts in each figure, and are as follows:-
a is the upright air duct; b the horizontal air flue; c, c hopper shoots or shelves
and air deflecting plates; d, d the trays or sieves; e, e rails on side of horizontal
flue, upon which the rectangular sieves or trays slide. The arrows f, f indicate the
direction of the air currents through the air passages between the upper shoots.
The arrows g, g indicate the direction in which the trays are moved along the rails
as herein before described.
In Figure 3 h, h indicates a valve shutter or door for regulating the main supply
of hot air.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
The combination, as described and shown, of upward air duct, horizontal flue
above same, hopper shoots or deflecting plates and intermediate air passages, and
rows of superimposed trays, to form an apparatus for employing heated air in
drying or baking vegetable or other substances, all substantially as described and
represented in accompanying drawings.
Dated this 2nd day of December 1885