IMPROVEMENTS IN KILNS FOR DRYING GRANULAR SUBSTANCES
Year: 1885

page_text: I, WILLIAM DAVIDSON of Mill of Clola, Mintlaw, in the County of Aberdeen,
Miller, do hereby declare the nature of my said Invention for "IMPROVEMENTS IN
KILNS FOR DRYING GRANULAR SUBSTANCES," to. be as follows:-
This Invention consists of improvements in the construction of kilns or apparatus
for drying corn and other kinds of grain or granular substances.
The improved drying kiln consists of a chamber of any ordinary kind, provided
with a floor formed of wire or of perforated metal or other material, the
perforations or openings in which are of such size as to retain the grain in bulk,
but to permit of its passage through the floor when motion is communicated either
to the floor or to the grain. The grain or substance to be dried is fed on to this
perforated floor by a hopper extending partially or entirely across the chamber,
and supported at its ends on slides or on wheels, so that it may be traversed in a
direction at right angles to its length over the floor. This hopper is open at the
top and is filled with grain either continuously by means of flexible bags, or is fed
as it reaches the side of the chamber at each traverse which it makes across the
chamber. In the bottom of the hopper is a slit through which the grain falls on
to the perforated floor; and the bottom of the hopper is within a short distance
from the floor, or is fitted with an adjustable board close thereto for the purpose of
spreading the grain into a comparatively thin layer on the floor, the lower edge of
the board being by preference indented. Motion is communicated to the layer
of grain by a perforated plate resting over the floor, or by a traversing board or
brush or similar means, or by imparting a jigging motion to the floor itself, or by
the lower edge of the traversing hopper; and by such motion the grain is caused
to fall through the floor in a shower into a trough or chamber below, preferably
of V shape, from the bottom of which it is removed by a screw or by bands, or
simply by its own gravity if the bottom of the chamber be inclined. During the
passage of the grain through the floor, heated dry air or the hot products of
combustion of a furnace is or are led into the chamber below the kiln floor by
suitable pipes or conduits entering at one or more points in the sides of the
chamber, the inlets being covered by inclined plates to deflect the grain. The
heated air or furnace gases pass upwards through the shower of falling grain and
through the perforated floor, and the grain lying thereon to the roof of the kiln
building or to a chimney, or they are drawn through by a fan or exhauster, the
containing walls of the kiln chamber being sufficiently close to exclude the outer
air. The improved kiln may be used as an ordinary kiln, from which the grain
is removed by shovels, by fitting a wire-cloth floor over the perforated floor
described.

page_text: Improvements in Kilns for Drying Granular Substances.
I, WILLIAM DAVIDSON, of Mill of Clola, Mintlaw, in the County of Aberdeen,
Miller, do hereby declare the nature of my invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying Sheet of
Drawings, and to the reference letters and figures marked thereon, that is to say :-
My said invention consists of improvements in the construction of kilns or
apparatus for drying corn and other kinds of grain or granular substances.
And in order that the full nature and novelty of my said invention, and the
mode of performing or putting it into effect or practice, may be properly under-
stood, I shall now proceed to describe the several figures on the Sheet of Drawings
which I have hereunto appended for that purpose, the same letters indicating the
same parts in the several figures.
Figures 1 and 2 are sectional elevations taken on the lines 1-
-
-I and 2-2 in
the horizontal section Figure 3 taken on the irregular line 3- - -3 in Figure 1, all
of one arrangement and combination of the parts of a kiln, constructed in accordance
with my said invention.
Referring to these Figures, my said improved drying kiln consists of a chamber
or closed-in structure of brick work of any ordinary kind, preferably of a rectangular
or square form as shown by the outer walls A. This chamber is provided with
the drying floor B at a story or so above the ground level Z. The drying floor B
is shown constructed of large rectangular plates B, formed of thin longitudinal
ribs, with narrow open slits between, wide enough to pass the grain or other
granular substance to be dried. These plates B rest on longitudinal carrying
bars C, secured at their ends at the proper height in the walls A. of the upper and
lower chambers A', A². The floor B may, however, be made with elliptical or
round openings very close together, or be covered with wire cloth or light
perforated metal plates or other open material, the perforations or openings in the
Hoor being of such a size as to retain the grain in bulk but to permit of its passage
through the floor when motion is communicated either to the grain or to the floor.
The perforated part of the floor or plates may have bars or open plates above these
moved to agitate the grain or granular substance above down through the openings
in the floor. The grain or substance to be dried is fed on to this perforated floor B
by a hopper D, preferably extending across the entire chamber A³, and carried by
wheels D D in suitable journal bearings secured to its ends, so that it may be
traversed on said wheels on rails D2 D2 on the side walls A, in a direction at right
angles to the length of this movable hopper over the floor B. This hopper D is
traversed to and fro from one side of the chamber A' to the other preferably by
two endless wire or other ropes & attached to the upper opposite ends, and passed
a few turns round the drums d' secured on a driving and reversible shaft d²,
carried in suitable journal bearing brackets d³ secured to one of the side walls A,
on the outside of the upper chamber A'; while at the opposite wall the ropes d
are each passed over a guide pulley d carried in journal bush bearing brackets d³
'

page_text: secured in proper position to the outside of the said opposite wall. The driving
drum shaft d² would be actuated through any ordinary arrangement of reversing
double clutch and wheel gear, or by a reversing open and cross belt arrangement
with intermediate slack pulley, by making the traverse of the hopper D, just
before reaching each end, shift a rod for the purpose to and fro, and through levers
either reverse the clutches in the one or the belt forks in the other arrangement,
to reverse the drum shaft d² and its ropes d, which would also reverse the motion and
traverse of the hopper D, continuously and automatically as required. The hopper B
is open at the top and is filled with grain as required, either as it reaches the ends
of its traverse across the chamber A¹ and floor B, or it might be continuously
by means of movable or flexible bag feeding tubes; in either case, from a floor Aй
above the chainber A', or by elevators to a feeding hopper A" above. The bottom
at d of the hopper D, is formed with a narrow slit along its whole length,
through which the grain falls in a regular stream on to the perforated floor B, and
the bottom of the hopper is traversed within a short distance from the floor and
determines the depth of grain desired to be laid on the floor as from 5 to 10 inches,
or so, as found best in practice. In some cases the bottom edge of the hopper may
be fitted with adjustable slides for regulating the thickness of the stream of grain
to be fed down on the floor, as shown at d*; and the lower edges of these slides
would preferably be indented or serrated, as shown dotted at dx to give greater
movement to the grain and allow the heat to pass freely and act more regularly on
the grain. Motion is communicated to the layer of grain, or the lower part of
same, in this arrangement by a series of blades 6 preferably passed up from below
into the grain one through each slit in the plates B of the floor, and secured below
to the transverse bars b₁ of a reciprocating frame, bound together by tie guide
rods 62, which work through guides on or holes in the cross bars C supporting the
perforated floor B. This frame 16 of blades b is traversed to and fro to the
extent of the length of the slits in the rows of plates (and in which the blades b
traverse) by wire ropes 63 passed a turn or two round driving drums b* on the
driving and reversing shaft 65 carried in suitable bearing brackets on one of the
side walls A, and passed over guide pulleys 6º, carried in suitable bearing brackets
in the opposite wall A of the kiln, and reversed all as described in reference to
the motion of the drum shaft 2 of the hopper D, or by other suitable reversing
gear. This reciprocating motion of the frame of blades b gives such motion to
the grain as causes it to fall through the narrow slits in the floor B as it is dried
in a shower down into and through a deep. hopper-shaped hot chamber B' below,
preferably of V-shape. From the bottom of this chamber B¹ the grain is removed
by its own gravity through an inclined shoot B³ (with an opening slide door B')
fitted and secured at the bottom of the chamber B, and led to one side of the lower
chamber A² into bags, or it might be into elevators when preferred. But the dried
grain might, when desired, be removed or elevated direct from the bottom of the
hot chamber B' by ordinary screw, bucket, or band grain carriers when preferred.
While the grain is so spread in a thin layer on the perforated open floor B and
during its passage through the floor, heated dry air or the hot products of com-
bustion from a furnace is or are led into and up through the chamber B', below the
kiln floor B, by suitable flues or conduits e entering at one or more points e¹ in the
sides of the chamber B¹ the inlet at e¹ being covered by inclined plates e² to deflect
the grain off the hot air entrances e¹. The heated air or furnace gases pass
upwards through the shower of falling grain and through the perforated floor B
and the layer of grain lying thereon into the chamber A¹ and through the
ventilators at A³ in the roof of the kiln building A, or to a draught chimney; or
the hot gases and vapour from the grain may be drawn off or through the kiln by
a fan or other exhauster; the containing walls A and B of the kiln chamber A¹, B',
being built of brick or other material sufficiently close to exclude the outer air.
The heated air or gaseous products of combustion might be led to the flues é of the
chamber B from any ordinary convenient furnace or stove, or it might be from a
steam air heating apparatus. But I prefer to have the whole arrangement and

page_text: combination self contained within the same kiln walls A, and for this purpose
I erect an ordinary construction of coal or coke fire or furnace or oven F, below
and to one side of the hot chamber B¹ of the kiln, to be fired at the doors F¹,
in front of and from the outside of one of the walls A. To the fireplace F* of the
furnace, as well as to the ashpit F³ below it, suitable arrangements of doors would
be fitted to regulate the proper admission of air to suit the combustion and heat
of the furnace desired and that of the hot gases allowed to pass from the back flues
of the furnace at f up into those e leading direct into the lower chamber B' of the
kiln, all as previously described. Valves or dampers may be fitted to admit a
regulated quantity of cold or outer air to the back of the furnace or flue for e to
mix with the hot gases from the furnace and so regulate the temperature of the
gases admitted to the hot chamber B¹ of the kiln. Arches A₁ with light built-in
closing walls, or doors, might be formed in the side walls A of the lower
chamber A, outside of and around the hot chamber B', for getting into the
dampers or doors of the flues f and e at the back of the furnace F, and lower
part of the chamber B¹, for cleaning these flues from time to time as may be
required.
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
First. The general construction or combination of the parts of kilns, for the
drying of corn or other kinds of grain or granular substances, substantially as
herein described, and shown in the accompanying Drawings.
Second. In kilns for drying grain or other granular substances, the combination
of a perforated floor, with close heat chamber and furnace below, for causing the
hot products of combustion to pass up through the kiln chambers and drying floor
and substance being dried on it, while this is falling in a shower through the
drying floor and ascending hot gases, all substantially as herein described, and
shown in the accompanying Drawings.
Third. The construction of kilns for the drying of grain or granular substances,
with a perforated bottom through which the lower or dried layer of the substance
being dried is made to pass down in a shower through the heated air or gases
ascending to the drying perforated floor above, substantially as herein described,
and shown in the accompanying Drawings.
Fourth. In kilns for drying grain or other granular substances in a layer on
open board or perforated floors, the removing of the lower part of the layer as it
is dried in a shower through the drying floor by giving motion to the grain or
granular substance being dried, substantially as herein described, and shown in the
accompanying Drawings.