Improvements in Apparatus for Drying Tea, Grain, and other substances.
Year: 1892

page_text: Date of Application, 23rd Jan., 1892
Complete Specification Left, 8th Sept., 1892-Accepted, 12th Nov., 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Drying Tea, Grain, and other
substances.
I EDWARD ROBINSON of 4 Castelnau Gardens, Barnes, in the County of Surrey,
Merchant do hereby declare the nature of this invention to be as follows:-
The principle carried out in this method of drying may be described as the
spiral principle. Volumes of heated air are obtained by means of a spirally constructed
heater & driven into a spiral apparatus adapted for carrying the material to be
dried. The arrangement for heating the air is as follows:-
Tubes of brass or other suitable material are made to pass through the blades of
The ends of the tubes
an Archimedean screw in the direction parallel to its axis.
are expanded into tube plates or otherwise made steam-tight. The sheaf of tubes
thus fitted into orifices along the whole length of the spiral is encased in a
cylindrical shell, in one end of which is an aperture for the admission of air, & at
the other end is a similar opening for the outlet of the air.
A fan or blower is connected to one of these apertures & may either exhaust, or
drive wind through the apparatus. The tubes are by preference placed in circles
in the heater, & their number & size must be adapted to the work required. The
wind is thus made to circulate round among the tubes by means of the spiral
diaphragm. The open ends of the tubes are enclosed in small steam chambers
which are attached to the outer rims of the tube plates, & steam being admitted
into one of these chambers passes freely into all the tubes, over the outside of which
air is being made to circulate as described. The passage of air through the heater
being thus prolonged through its spiral course large volums can be heated to the
same temperature as the steam if required. A drain pipe is inserted in one of the
steam chambers to carry off the condensed water. Heaters such as this can be
placed side by side & connected together so that air having passed through one
heater is drawn into another. By this means air is soon heated to the same
temperature as the steam. Either exhaust or live steam can be used as required.
Wind thus heated is distributed by means of orifices in a tube which passes into
a cylinder carrying the material to be dried. This part of the apparatus consists
of a revolving cylinder carried on rollers & driven by means of a cogged pinion, or
other suitable arrangement. A stationary tube runs through the center, supported
by bearings at each end, & provided with specially constructed nozzles arranged at
equal distances apart for the uniform distribution of the wind in the cylinder.
Surrounding the center tube, & attached to the shell of the revolving cylinder is a
series of spirally constructed baskets or chambers running the whole length of the
cylinder, with intervening spaces between each spiral chamber to provide for the
free circulation of wind, & a suitable pitch for the onward movement of the material
under treatment. The material to be dried is admitted through an aperture in one
end of the cylinder near the center tube, & is received into a round vertical
chamber. A diaphragm partition is attached to the outer shell & vertical end of the
cylinder, about at right angles to the axis of rotation, & at each turn of the
cylinder the material introduced is carried upwards. upon the diaphragm & is
made to fall into the first quadrant of the spiral series. These continuous circular
chambers are separated into four equal compartments by means of diaphragm
partitions similar to the one just described, attached to the periphery of the cylinder.
Suplemented however by a second smaller diaphragm placed nearly opposite the
one described, & fastened to the part of the chamber immediately surrounding the
center tube. These diaphragms are placed at such angles as to carry the material
round the entire circle at each turn of the cylinder, pouring it gently down from
.

page_text: the upper elevation into the succeeding quadrant, thus only advancing the material
one quarter of the spiral circle at each turn of the cylinder. By this means it is
slowly carried through the whole series; equally distributed through the cylinder &
kept in constant motion by being carried upwards & allowed to trickle down in
thin streams fully exposed to the drying action of the wind. An opening is left in
the shell of the cylinder at the terminal end of the spiral series & at each turn the
contents of one section is discharged.
The spiral chambers must be made of wire work of such gauge & texture as may
be best suited to the nature of the commodity to be dried. Or thin perforated
plates such as tin or zinc may be used, the main object being to secure the freest
action of the wind compatable with such mesh, or texture as will prevent the
material from falling through.
At each end of the cylinder wire or perforated discs are provided for the outlet
of the moist air which is rapidly expelled by the inrush of wind from the center
tube.
-
By means of pullies of different sizes the machine can be driven at any required
speed so as to pass the 'material through quickly, or prolong the operation
according to the time needed to complete the work.
A self-acting contrivance is adopted for feeding the material into the cylinder,
which can be so regulated as to supply the desired quantity with constant regularity.
In the case of tea for example a hopper is provided suitably converging towards the
bottom where an opening is adjusted by means of a slide, & the leaves or other
substances are shaken through it by means of revolving tines into a horizontal
tube in which revolves a spiral propellor. This feeding tube is placed close to the
stationary central tube & is made to just enter through the end shell of the
revolving cylinder, so as to drop its contents into the first vertical chamber herein
before described. For heavier granular matter, such as will readily run down a
shoot a more simple means of feeding may be used.
January 23rd 1892.
"
COMPLETE SPECIFICATION.
Improvements in Apparatus for Drying Tea, Grain, and other
substances.
I EDWARD ROBINSON of 4 Castelnau Gardens Barnes in the County of Surrey,
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 :-
..
This invention relates to apparatus for drying tea, sugar, grain and other
substances. The invention consists in a drying apparatus of novel construction in
which volumes of heated air are obtained by means of a spirally constructed heater,
and driven into a revolving spirally constructed drier adapted to carry and pass
the material to be dried through it, substantially as hereinafter described and more
particularly pointed out in the claims.
1
Reference is to be had to the accompanying drawings forming a part of this
Specification, in which similar letters of reference indicate corresponding parts in
all the figures.
:
Figure 1 is a side elevation of the apparatus complete ;
Figure 2 a partly sectional and broken side elevation, upon a larger scale, of that
portion of the apparatus which provides for the heating of the air to be used in the
drier; and
1.11
"1
! : "
•
Figure 3 a transverse section upon the line 33 in Figure 2; of one of the
tubular cylinders of the heater;"
"
1
. ܂
Figure 4 is a half or partially sectional side elevation of the drier and feeding.

page_text: Figure ɔ a transverse section upon the line 5-5 in Figure 4;
Figure 6 is a transverse section mainly upon the line 6-6 in Figure 4; and ›
Figure 7 a transverse section maiuly upon the line 7-7 in Figure 4.
The air heating portion of the apparatus is constructed mainly as follows:
AA are parallel cylinders or shells each of which is fitted internally with a spiral
divider B resembling in shape an Archimedean screw and extending throughout the
diameter and length of the body of the shell. Tubes C of brass or other suitable
material are arranged to pass through the spiral dividers in directions parallel to
the axes thereof, and the ends of said tubes are expanded into the tube plates at
the ends of said shells or otherwise made steam tight. These tubes C pass through
orifices throughout the whole length of the spiral dividers B, and the shells of
cylinders A A are provided with distributing chambers 6 at their ends, two of
which at adjacent ends are connected by a pipe c, while the one of them at the
opposite end is provided with a steam inlet d, whereby steam is made to circulate
through the series of tubes in both cylinders or shells for the purpose of heating the
air to be passed to the drier, which air enters at an inlet e near the one end of one
of the cylinders A, passes through or about the spiral divider B in said cylinder,
thence out through a branch pipe to one end of the air space in the other
cylinder A, through or about the spiral divider B in that cylinder, and out through
an outlet
at the other end of such cylinder, from whence it may be drawn by a
fan D to supply the drying portion of the apparatus. Instead, however, of the air
being exhausted from the heater to supply the drier, it is evident that the air
may be driven through the heater for that purpose; nor is the heating portion of
the apparatus restricted to two cylinders fitted with spiral dividers and tubes
running through the dividers, which virtually form a unit, the same as if one
cylinder of twice the length similarly fitted were used, and it will suffice to speak of
the two cylinders as one. In the fitting up of this heater it is preferred to arrange
a central tube of larger size through the cylinder and its spiral divider and to place
the other tubes of smaller size in circles around it. The number and size of the
tubes however must be adapted to the work to be done. By means of the spiral
divider, the air to be heated is made to circulate around the tubes and its passage
through the heater is prolonged through its spiral course of travel, so that large
volumes of air can be heated to about the same temperature of the steam passing
through the tubes, if required. A drain pipe or steam trap can be applied to one
of the steam chambers to carry off, as required, the water of condensation and the
said water may be returned by any suitable means back to the boiler in which the
steam was generated, thus supplying the means of drying in the apparatus at a very
cheap rate. If desired, instead of supplying the heat by steam, the gaseous
products of combustion from a furnace may be passed through the tubes of the
heater, and if advisable be returned through a flue on the outside of the cylinder.
It is unnecessary, however, here to describe in detail these and other changes and
details or how the heater may be set in brickwork, as others skilled in the art of
utilizing heat as derived from furnaces either directly or through the intervention
of steam, live or exhaust, will readily understand how such may be done.
The main feature of this part of the apparatus is the action of the spiral divider
which prolongs the travel of the current of air while being exposed to the action
of the heat or of heated gases or steam, thus utilizing and economizing the
absorption of the heat to the greatest extent, but this advantage would be lost or
largely diminished were such heated current of air not applied or distributed and
imparted to the material to be dried in a like prolonged and efficient manner,
consequently I caused said heated current of air to be similarly applied by sub-
jecting the material to be dried to a confined spiral course of travel while under
exposure to the heated current or currents of air passing through the drier as the
same is transferred thereto, by the fan D, for instance, for distribution within and
through the material to be dried.
The construction of the drier or drying portion of the apparatus will now be

page_text: described in connection with the operation of the same. Thus, the blast or current
of heated air passes, as it is sucked or driven from the heater, into a horizontal
tube E, carried by opposite end standards or bearings h h, which tube is provided
with orifices or nozzles i, for distribution of the heated air within a cylinder G,
carrying the material to be dried as hereinafter described, said tube being con-
carried rollers kk,
centric with the cylinder. This cylinder is a revolving one, upon
and may be driven by a circular rack l, on said cylinder in gear with an operating
pinion m on a shaft below, which may be driven by pulleys from an overhead shaft
that may be used to also drive the fan D as shown in Figure 1, but these driving
arrangements may be changed as desired. The apertured tube E is stationary and
its nozzles i are arranged at equal distances apart for the uniform distribution of
the heated air within the cylinder. Loosely surrounding the central tube E and
attached to the shell of the revolving cylinder G is a spirally constructed divider H,
running throughout the length of the cylinder and constructed to form a continuous
series of spirally constructed and connecting chambers n n, preferably made of'
reticulated material and having intervening spaces between them to provide for the
free circulation of the heated air within the cylinder, and of a suitable pitch to
provide for the onward movement of the material to be dried through the cylinder
for ultimate delivery through an opening o at the one end of the cylinder. The
material to be dried is admitted through an opening s at the opposite end of the
cylinder near to the center tube E, and is received within a round upright or
transverse chamber a¹, virtually forming an end extension of the spiral divider H
and provided with a diaphragm partition b', attached to the outer shell and vertical
end of the cylinder, nearly at right angles to its axis of rotation, and at each turn
of the cylinder the material introduced is carried upward by the diaphragm and is
made to fall into the first of the spiral series of chambers n for onward travel
through the whole series of continuous spiral chambers toward the delivery end of
the cylinder. These chambers are divided into four, more or less, equal spaces by
means of inward angular or tangential diaphragms e' attached to the periphery of
the cylinder, and supplemented by a second series of smaller diaphragms d¹ placed
nearly opposite the first series c¹ and secured to the chambers n and to the tube
like continuation k¹ which forms that side of the reticulated spiral chamber near to
the center air distributing tube E. These several diaphragms are placed at such
angles as to carry the material being dried round in a complete circle at each
revolution of the cylinder, thereby gently passing said material from an upper
Llevation into the next succeeding spiral chamber and so on throughout the whole
length of the spiral divider H and only advancing the material one quarter of each
spiral circle or portion of the divider at each turn of the cylinder. By these means
the material being dried is slowly carried through the whole series of spiral chambers
or baskets, equally distributed round the cylinder and kept in constant motion and
allowed to trickle down in thin streams freely exposed to the drying action of the
heated air passing through the cylinder, and the contents of each spiral section of
the divider is delivered in succession at each turn of the cylinder through the
terminal delivery outlet o in the cylinder.
The several continuous spiral chambers n of the divider H are made of wire of
such gauge, texture or mesh as may be best suited to the nature of the commodity
to be dried; or thin perforated plates, such as of tin or zinc for instance, may be
used in the construction of the said chambers, the main object being to secure the
most free action of the current of heated air on the material under operation,
compatible with such mesh or texture, as will prevent the material from falling
through said chambers. Suitable special openings may be made at both ends of
the cylinder G, or central openings similar to the one s, shown, be provided at
opposite ends of the cylinder, to admit of the escape of air charged with moisture
from the material being dried and which will be rapidly expelled by the incoming
heated air from the central tube E.
By employing pulleys of different sizes as shown in the drawings, the apparatus

page_text: can be driven at any required speed, so as to pass the material quickly to be
dried, or to prolong the operation according to the time required to complete the
work.
A self acting contrivance is applied to feed the material into the cylinder G
which can be regulated at will. It consists of a hopper f¹ in which revolves a
corrugated drum g'or tines as the case may require, feeding the material into a
horizontal tube h¹ fitted with a small spiral propeller . This feeding tube_is
placed in proximity to the central tube E so as to drop its contents into the
receiving chamber of the spiral divider H. But no claim is here made to any
special feeding device of the material, and for heavy granular matter, such as will
readily run down a shoot other and simpler feeding contrivances may be used.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. In an apparatus for drying granular and other substances by means of currents
or blasts of heated air, the combination, with a drying cylinder, of an air heating
cylinder or structure provided with a spiral divider arranged in direction of its
length, and with a series of steam or other heating tubes passing through said
spiral divider, and means operating to pass a current of air through said heating
structure and drying cylinder, substantially as specified.
2. A rotatable cylinder for drying granular and other substances, provided
internally with a spiral divider constructed to form a continuous or connected series
of spiral reticulated chambers, adapted to carry and advance the material to be
dried through said cylinder, subject to a current of heated air passed through the
latter, essentially as described.
3. In an apparatus for drying granular and other substances, the rotatable drying
cylinder provided internally with a spiral divider rotating in common with said
cylinder, and constructed to form a continuous or connected series of spiral
reticulated chambers adapted to carry and advance the material to be dried
through said cylinder, and provided with a receiving compartment or chamber at
its forward end having a diaphragm adapted to pass the material to the first of the
series of spiral reticulated chambers, in combination with a central heated air dis-
tributing tube within the cylinder, having nozzles or apertures for the distribution
of said air, and a series of diaphragms within the reticulated spiral chambers
operating to agitate and control the movement of the material from each spiral
chamber to the next in succession, substantially as specified.
4. The combination of the rotating drying cylinder G, with its internally fitted
spiral divider H, constructed to form a continuous or connected series of reticulated
spiral chambers adapted to carry and advance the material to be dried through
said cylinder, the central heated air distributing tube E, within the cylinder, having
Dozzles or outlets i, and an air heating cylinder or structure A, provided with a
spiral divider B, arranged in direction of its length, and with a series of steam or
other heating tubes Č, passing through said spiral divider H. and means for
passing the current of heated air through the drying cylinder, essentially as
described.
Dated this 30th day of Anomet. 1892
EDWARD ROBINSON.