Method and Apparatus for Drying Granular and like Materials.
Year: 1894

page_text: Date of Application, 31st Dec., 1894
Complete Specification Left, 2nd May, 1895-Accepted, 27th July, 1895
PROVISIONAL SPECIFICATION.
Method and Apparatus for Drying Granular and like Materials.
I, EDWARD MITCHELL COOK, of 76 Park Place, City of New York, County
of New York, State of New York, U.S.A. Gentleman, do hereby declare the
nature of the said invention for Method and Apparatus for Drying Granular and
like Materials, to be as follows:-
The object of this invention is to furnish an improved method and apparatus for
drying granular materials as lime, fertilizers, beer grains, and analogous substances,
and the invention relates to that class of apparatus in which the material under
treatment is subjected to a current of heated air which is recirculated through the
apparatus and thus brought into repeated contact with the material.
Heretofore, the heat required to produce the desired evaporation has been
imparted to the air by passing the entire recirculating current over heat radiating
surfaces and constantly discharging a portion of the nearly saturated air from the
apparatus and admitting a corresponding amount of new air thereto.
In the present invention I do not move the recirculating body of air into contact
with any heating surfaces; but circulate a given current continuously in a circuit
through the drying chamber, and replace the discharged portion by an equivalent
quantity of highly heated air or gas.
In such method of operation, preferably employ the gascous products of com-
bustion from a suitable furnace, such highly heated gases being introduced to the
current in a mixing chamber and thus tempered to a suitable point before their
admission to the material.
The heat required for continuous evaporation is thus introduced, while the
temperature of the air coming in contact with the material is controlled by the
relation between the volume of the recirculated current and the air admitted and
discharged. The recirculated current in its passage through the drying chamber
loses heat and gains humidity until it reaches the terminal point, where the proper
proportion of air is discharged, bearing with it the evaporated moisture; and the
remainder of such air current is then passed through a suitable mixing chamber
where the highly heated gases raise the current to the temperature appropriate to
the material under treatment.
The method described may be practiced with an apparatus in which the material
is moved either vertically or horizontally. In apparatus in which the material is
moved vertically, I prefer the form of drier employing numerous series or tiers of
oscillating duplex troughs, and in apparatus moving the material horizontally, I
prefer a series of endless aprons placed one over the other, and moved in opposite
directions.
I will describe the invention with reference to the vertical form of apparatus, in
which I employ a tower of suitable height and suitable dimensions to enclose the
vertical drying chamber, with a vertical mixing chamber at one side thereof, and a
space for containing an elevator chain with lifting buckets at the opposite side, all
of the parts of the apparatus being thus supported most conveniently in their proper
relations.
The drying chamber is provided at the top with a feed bin, and the elevator is
arranged to receive the material at the base of the tower, and to discharge it

page_text: through a shute into the feed bin. The bottom of the feed bin is formed with a
series of slots having concave walls, between which a series of oscillating valves is
fitted, and arranged to receive the material when turned in one position; and when
turned in the reverse position, to carry a definite charge of the material downward
adjacent to the concave wall and discharge it at the bottom of the slot.
The partitions between the slots are formed at the top with acute edges, and a
series of levelling blades are arranged to move continuously across the upper part
of the bin below the feed shute, to level the material and thus secure a uniform
discharge through the valves at the bottom of the bin. To thus level the
material, two rotary shafts carrying chain wheels are mounted transversely across
the bin near the middle line, and two similar shafts are mounted at the edges
of the bin.
Endless chains connect the wheels upon the middle shafts to those at the edges,
and carry transverse bars with blades, which are propelled from the center of the
bin toward the sides.
This apparatus is adapted for use upon a large scale, in which the tower would be
from forty to eighty feet in height; and an operator at the base of the tower may
be advised when the bin is filled to a certain level, by providing an overflow channel
at a suitable level upon the side of the bin, and conducting the same to a point
where the operator below can control the supply of material to the bin.
The shute discharges the material into the bin between the middle shafts, and
the levelling blades by their movement distribute the material toward the sides of
the bin, and may also be inclined to throw the material from the center toward the
ends of the bin.
The drying chamber is provided with numerous series of oscillating duplex
troughs arranged in horizontal tiers, the pivots extending outside the wall of the
chamber, and the cranks of the alternate tiers being linked together and coupled to
a common connecting rod.
The oscillation of such rod thus operates the alternate tiers of troughs. The
duplex troughs are arranged parallel to one another, and when one is turned upward
to receive the material the other is turned downward sufficiently to discharge the
material upon the tier of troughs below. An oscillating lever is mounted at the
bottom of the chamber, and the two connecting rods of the alternate series of tiers
are jointed to the opposite ends of such lever. The oscillating valves of the feed
bin are provided with crank arms connected together and to the oscillating lever,
or to one having a similar motion. An arm is attached to the lever to vibrate
the same, and is provided with a crank pin to which reverse pawls are fitted.
The pawls are mounted upon a reciprocating frame, and are adapted respectively
to move the crank pin in opposite directions, and thus vibrate the oscillating
lever. A cam shaft is mounted upon the reciprocating frame with cams having
notches adapted to admit tail-pieces projected from the rear ends of the pawls.
A ratchet wheel is fixed upon a shaft which is mounted upon the reciprocating
frame and connected with the cam shaft by suitable gear wheels, and a stationary
spring tooth is fixed adjustably by the side of the reciprocating frame to engage
the teeth of the ratchet wheel at each reciprocation of the frame.
The continuous reciprocation of the irame thus produces a gradual rotation
of the cams until their notches coincide with the tail-pieces of the pawls, thus
causing the pawls to momentarily engage the crank pin and vibrate the oscillating
lever. The mere reciprocation of the cam shaft frame thus automatically and
intermittingly oscillate the duplex troughs as well as the oscillating carriers in the
bottom of the feed bin.
The spring tooth can be adjusted to push more or less of the ratchet teeth around
at each reciprocation, and the gear wheels connecting the two shafts can be varied
in their diameters at pleasure; thus furnishing a means of varying the feed to any
desired degree.
A suction fan is arranged near the base of the tower to draw the air from the
bottom of the mixing chamber and discharge it into the bottom of the drying

page_text: chamber, and an outlet for a suitable portion of the saturated air is provided at the
top of the drying chamber, and may be furnished with a suitable damper or with a
suction fan adapted to produce a regulated discharge. The two fans may be geared
together to maintain their proportionate movement if the speed be varied.
The furnace, if one be provided expressly for the purpose, is situated at the base
of the tower and its smoke flue extended upward nearly to the top of the mixing
chamber, where a suitable connection is provided with a damper to regulate the
discharge of the highly heated air to the mixing chamber. By the admission of
the heated air at this point it is mingled with the recirculated current in its move-
ment downward through the whole length of the mixing chamber, and is then
admitted to the bottom of the drying chamber through which it travels upward and
passes from the top, again, to the upper end of the mixing chamber.
The above is the preferable construction, but modifications may be made to suit
various conditions, provided the heat is supplied to the recirculating current by
replacing the discharged portion of the same with an equivalent quantity of highly
heated air or gas.
It is not essential to the operation of my improved method that a specific
chamber should be constructed to serve as the mixing chamber, as the mixing of
the highly heated gases with the recirculating current may be effected by intro-
ducing such heated gases directly into the suction fan, or into a pipe leading to or
from the end of the drying chamber to the same.
The heated gases may be taken from the chimney stack of a steam boiler, or
from any furnace employed for other useful purposes; thus utilizing the waste heat
of the same.
Dated this Twenty-first day of December 1894
Method and Apparatus for Drying Granular and like Materials.
1, EDWARD MITCHELL COOK, of 76 Park Place, in the City of New York,
County of New York, State of New York, U.S.A. Gentleman, 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 :-
The object of this invention is to furnish an improved method and apparatus for
drying granular materials as lime, fertilizers, beer grains, and analogous substances,
and the invention relates to that class of apparatus in which the material under
treatment is subjected to a current of heated air which is recirculated through the
apparatus and thus brought into repeated contact with the material.
Heretofore, the heat required to produce the desired evaporation has been
imparted to the air by passing the entire recirculating current over heat radiating
surfaces and constantly discharging a portion of the nearly saturated air from the
apparatus and admitting a corresponding amount of new air thereto.
In the present invention I do not move the recirculating body of air into contact
with any heating surfaces; but circulate a given current continuously in a circuit
through the drying chamber, and replace the discharged portion by an equivalent
quantity of highly heated air or gas.
In such method of operation, I preferably employ the gaseous products of
combustion from a suitable furnace, such highly heated gases being introduced to

page_text: the current in a mixing chamber and thus tempered to a suitable point before their
admission to the material.
The heat required for continuous evaporation is thus introduced, while the
temperature of the air coming in contact with the material is controlled by the
relation between the volume of the recirculated current and of the air admitted
and discharged. The recirculated current in its passage through the drying
chamber loses heat and gains humidity until it reaches the terminal point, where
the proper proportion of air is discharged, bearing with it the evaporated moisture;
and the remainder of such air current is then passed through a suitable mixing
chamber where the highly heated gases raise the current to the temperature
appropriate to the material under treatment.
The method described may be practiced with an apparatus in which the material
is moved either vertically or horizontally. In apparatus in which the material
is moved vertically, I prefer the form of drier employing numerous series or tiers
of oscillating duplex troughs, and in apparatus moving the material horizontally,
I prefer a series of endless aprons one over the other, and moved in opposite
directions.
I will first describe the invention with reference to the vertical form of apparatus,
in which employ a tower of suitable height and suitable dimensions to enclose
the vertical drying chamber, with a vertical mixing chamber at one side thereof,
and a space for containing an elevator chain with lifting buckets at the opposite
side, all of the parts of the apparatus being thus supported most conveniently in
their proper relations.
The drying chamber is provided at the top with a feed bin, and the elevator is
arranged to receive the material at the base of the tower, and to discharge it
through a shute into the feed bin. The bottom of the feed bin is formed with a
series of slots having concave walls, between which a series of oscillating valves
is fitted, and arranged to receive the material when turned in one position ;
and when turned in the reverse position, to carry a definite charge of the material
downward adjacent to the concave wall and discharge it at the bottom of the slot.
The partitions between the slots are formed at the top with acute edges, and a
series of levelling blades are arranged to move continuously across the upper part
of the bin below the feed shute, to level the material and thus secure a uniform
discharge through the valves at the bottom of the bin. To thus level the material,
two rotary shafts carrying chain wheels are mounted transversely across the bin
near the middle line, and two similar shafts are mounted at the edges of the bin.
Endless chains connect the wheels upon the middle shafts to those at the edges, and
carry transverse bars with blades, which are propelled from the center of the bin
toward the sides.
This apparatus is adapted for use upon a large scale, in which the tower would
be from forty to eighty feet in height; and an operator at the base of the tower
may be advised when the bin is filled to a certain level, by providing an overflow
channel at a suitable level upon the side of the bin, aud conducting the same
to a point where the operator below can control the supply of material to
the bin.
In the annexed drawing,
Fig. 1 is a side elevation of the apparatus with the front wall removed above
the line .2", and the figure broken for want of room upon the drawing.
Fig. 2 is an elevation partly in section on line 2, 2, in Fig. 6.
Fig. 3 is an elevation of the trough oscillating mechanism with the nearer
supporting beam removed; Fig. 4 is a plan of the same, with the shaft of the
oscillating lever broken for want of room.
Fig. 5 is a plan of the apparatus just above the furnace G with the oscillating
mechanism and the furnace omitted for want of room upon the drawing.
Fig. 6 is a plan of the feed bin.
Figs. 7 and 8 are diagrams showing, respectively, a sectional elevation and plan
of a horizontal drier.
5

page_text: Fig. 9 is a vertical section of the feed bin and top of drying chamber, on line 9, 9,
in Fig. 6.
T designates a tower of suitable dimensions to enclose the vertical drying
chamber A with vertical air mixing chamber B at one side thereof, and a space B¹
at the opposite side to accommodate the elevator B2, and give access to the cranks
which oscillate the troughs. A feed bin C is sustained in the tower above the
drying chamber A, and a spout C' discharges the material from the elevator into
the center of the bin. A discharge hopper D is sustained below the drying chamber
and receives the material therefrom. Spaces C' and D' are provided at opposite
ends of the drying chamber.
The air mixing chamber communicates with the top of the drying chamber
through the space C¹ beneath the feed bin, but is cut off from the space D' by a
partition D². A fan E is provided, as shown in Fig. 5, to draw the air from the
lower part of the mixing chamber through trunk E, and deliver it into the space D)¹
at the bottom of the drying chamber. An outlet pipe F in the top of the tower is
provided for a continuous discharge of the required portion of the partially saturated
air, and may be provided with damper as shown in Fig. 2, to regulate the discharge,
or may be furnished with a suction blower, the speed of which may be regulated
for the same purpose.
A furnace G is shown adjacent to the mixing chamber with its flue G₁ extended
upward by the side of the same and connected therewith near the top of the mixing
chamber by inlet H. A gate I is hinged upon the inlet and provided with weighted
lever and cord 12 to open the gate at pleasure. When closed the hot air escapes
at the top of the flue. The cord is shown in Fig. 6 extended to a pulley upon the
wall of the tower, from which pulley it may be carried to any convenient point for
actuation by the operator. The cord is not shown in Fig. 2 on account of the
smallness of the scale. The bottom of the feed bin is formed, as shown in Fig. 9,
with a series of slots having concave walls between which a series of oscillating
valves is fitted, each having two grooves or chambers of which alternately receive
and discharge the material from the bottom of the slot when the valve is oscillated.
The partitions between the slots are formed at the top with acute edges st. Two
rotary shafts J are mounted transversely across the bin near the middle line,
and provided with chain wheels J'. Shafts provided with similar wheels J'
are mounted near the outer edges of the bin, and endless chains connect the wheels
upon the middle shaft to those at the edges, and carry transverse bars k with
blades k².
The shute C2 discharges the material between the shafts J, and the chains are
so propelled as to carry the blades upon the under sides of the wheels from the
center of the bin toward the sides, thus distributing and levelling the material.
The blades, as shown in Fig. 6, are inclined from the middle line of the bin
toward the ends, so that the motion of the blades spreads the material in every
direction.
An overflow channel K is provided at a suitable level at the side of the bin to act
as a telltale indicator, and is conducted to a point where the operator can observe
the same and control the supply of material to the bin. The drying chamber is
provided with numerous series of oscillating duplex troughs t arranged in horizontal
tiers, and formed with adjacent longitudinal chambers which alternately receive
and discharge the material, when oscillated. The pivots of the alternate tiers are
provided with cranks u and the intermediate tiers with cranks u' outside the wall
of the chamber. The cranks of each tier are coupled by a common link . An
oscillating lever a is mounted upon the shaft a' in the bottom of the space B, and
connecting rods c and c¹ are coupled to the ends of the same, and to arms which
operate one duplex trough in each tier, and thus moves the remainder simultaneously
by means of the links w.
Cranks & coupled by link d¹ (indicated merely by dotted lines in Fig. 9) are
attached to the pivots of the valves t, and chains e³ are extended from a double
arm e upon one of the pivots to the oscillating lever a; thus securing the oscillation

page_text: of the feed valves when the duplex troughs are actuated. An arm is attached to
the shaft of the lever a and provided with a crank ping to which reverse pawls h, h',
are fitted.
The pawls are mounted by a pivot i upon a reciprocating frame L, which is
hinged upon pivoted arms M, one of which is provided with an arm Mactuated 3
by an eccentric Q. The eccentric is shown in Fig. 1 mounted upon a shaft having
a driving pulley Q' which, like the spindle of the fan E, would be rotated by any
suitable means.
Cams 1,, are mounted by a shaft m upon the frame and provided with notches
adapted to admit tail-pieces m' projected from the rear ends of the pawls.
A ratchet wheel n is fixed by a shaft o upon the same frame and connected with
the cams and their shaft m by gear wheels p, and a pawl or tooth is fixed
adjustably by the side of the reciprocating frame to engage the teeth of the
ratchet wheel at each reciprocation of the frame. The tooth is shown pressed
normally toward the periphery of the ratchet wheel by weight q'. The oscillation
of the frame moves the edge of the ratchet wheel over the end of the tooth,
and causes the latter to engage the ratchet teeth and push the wheel around as
desired.
The pawls are provided with hooks e, e', which point in opposite directions, and
with fingers which guide the hooks into contact with the crank pin y, and the
cams,, have their notches arranged opposite one another, so that the pawls are
permitted to fall alternately into engagement with the crank pin. The first
reciprocation of the pawl, after the tail-piece m' has fallen into the notch of the
cam, serves to shift the arm f (as shown of the pawl in Fig. 3), and thus to
actuate the oscillating lever a, the duplex troughs, and the valves v.
The subsequent reciprocations of such pawl produce no further effect, and the
succeeding rotation of the cams operates to raise such pawl and to drop the opposite
pawl after a suitable interval of time. The feed bin being filled and the material
suitably leveled, the valves v serve to discharge an equal supply of the material
upon all of the duplex troughs in the upper part of the drying chamber.
The acute edges s¹ upon the partitions between the valves serve to prevent the
clogging of the material and to lead it freely into the valve chambers . The
material drops through the space Cupon the upper tier of troughs, and is
space D'
discharged downwardly from one tier to another until it drops through the
into the hopper D; from whence it would be discharged and removed in any
suitable manner.
The operation of the recirculating current, as indicated by arrows, in Fig. 2,
is as follows:
The fan E continuously circulates the air through the mixing chamber and
drying chamber, by drawing it from the mixing chamber and discharging it into
the lower part of the drying chamber, or space D', from whence it passes upward
between the troughs and falling material, and enters the upper end of the mixing
chamber through the space C.
At this point, the recirculating current receives the desired proportion of highly
heated air from the flue inlet H, such portion of air being determined by the
discharge of saturated air from the outlet pipe F in the top of the apparatus.
Before such highly heated air enters the drying chamber, it mingles with the
recirculated current in its progress through the entire length of the mixing
chamber, and through the fan E, and is thus reduced to the desired temperature
before it enters the drying chamber. A drier with horizontal movement of the
material is shown in Figs. 7 and 8, where the drying chamber A. contains a series
of endless aprons A¹, which extend nearly to the ends of the chamber, leaving the
spaces C and D' at the opposite ends.
An aperture A³ is shown at the top of the drying chamber and another A2 at
the bottom, to represent the inlet and outlet for the material. The furnace G is
shown with passage H extending directly into the space C, provided with dampers
or valves 13.

page_text: The fan E is placed adjacent to the space D' outside of the drying chamber and
connected therewith with a suitable inlet pipe, and the air mixing chamber is.
formed of a pipe B connecting the suction inlet of the fan with the space C¹.
The outlet Fin the top of the mixing chamber is shown provided with a blower F
to regulate the discharge, and thus determine the influx of heated air through the
inlet H. The furnace is shown supplied with a separate chimney flue G² and with.
damper G³.
The operation of the air current is precisely the same in this construction, the
recirculating current moving from the space D' to the space C¹, where its
temperature is renewed with the desired proportion of heated air; which is mixed
therewith in the pipe or chamber B, and then discharged by the blower into the.
space Di
It will be understood that in the construction shown in Figs. 7 and 8, suitable
belts and wheels would be provided to impart the necessary motion to the aprons A',
the fan E and the blower F, and such connections are not shown upon the drawing
as they form no part of the present invention, and their nature is already well
understood.
It is immaterial how the rotary motion be imparted to the pulley s³ which
actuates the levelling blades, to the elevator, to the fan E, and the eccentric Q,
which operates the feed devices; but I have shown in Figs. 1 and 2 suitable
connections for conveying the motion to these parts from a single shaft R.
Pullies and belts, to furnish such connections, are shown in dotted lines to avoid
obscuring the other parts of the drawing, a pulley R¹ being furnished to drive the
blower by a suitable belt r, a pulley or sprocket wheel S to drive the shaft of the
eccentric Qby helt s, and belts and being applied to suitable pullies or
sprocket wheels for driving the elevator and one of the shafts J.
Fig. 6 shows spur wheels 2 connecting the shafts J, and the wheel s³ for
receiving the belt s².
Link belts would be used if sprocket wheels are employed.
The drawings illustrate the preferable construction, but it is obvious that
modifications may be made to suit various conditions provided the heat is supplied
to the recirculating current by replacing the discharged portion of the same with
an equivalent quantity of highly heated air or gas.
By employing the vertical form of apparatus, the material is permitted to fall
repeatedly, and the air current is brought more effectively into contact with the
material than where it is supported by travelling carriers or aprons during the
greater part of its passage through the apparatus.
It is not essential to the operation of my improved method that a specific
chamber should be constructed to serve as the mixing chamber, as the mixing of
the highly heated gases with the recirculating current may be effected by
introducing such heated gases directly into the suction fan, or into a pipe leading
to or from the end of the drying chamber to the same.
The beated gases may be taken from the chimney stack of a steam boiler, or
from any furnace employed for other useful purposes, thus utilizing the waste heat
of the same.
Having now particularly described and ascertained the nature of my said
invention, I declare that what I claim is:
1. A drying apparatus comprising a drying chamber with an outlet for
discharging a regulated portion of the saturated air, an air mixing chamber for
mixing the partly saturated air with a fresh portion of highly heated air, the
mixing chamber having connections at opposite ends to the drying chamber with a
circulating fan interposed in one of the said connections, and the said mixing
chamber having an inlet for heated air, the whole arranged and operated as herein
set forth.
2. A drying apparatus comprising a drying chamber having an inlet for the
material, with means for advancing the material progressively through the chamber,

page_text: and means for discharging a regulated proportion of the saturated air, a separate
air mixing chamber having connections to the drying chamber at opposite ends
with a circulating fan interposed in one of said connections, and the said mixing
chamber having an inlet for heated air, the whole arranged and operated
substantially as herein set forth.
3. In a drying apparatus, the combination, with a vertical drying chamber, of a
feed bin at the top of the chamber with valves in the bottom, a shute for delivering
the material into the bin, levelling blades arranged to move across the upper part
of the bin, and an overflow chaunel adjacent to the level of the blades to serve as
a tell-tale indicator.
4. In a drying apparatus, the combination, with a vertical drying chamber, of a
feed bin at the top of the chamber, the feed bin having a series of concave-walled
slots in the bottom, acute edged partitions between the slots, and a series of
oscillating carriers fitted to the concave walls of the slots, with means for actuating
them intermittingly.
5. In a drying apparatus, the combination, with a tower containing a vertical
drying chamber, with a vertical air mixing chamber at one side of the same, and
an elevator chain with lifting buckets at the opposite side of the same, of a furnace
with outlet for the heated gases into such mixing chamber, a feed bin at the top of
the drying chamber with shute leading from the elevator, and sundry series of
oscillating duplex troughs pivoted in tiers within the drying chamber, and means
for oscillating the troughs, substantially as herein set forth.
6. In a drying apparatus, the combination, with a drying chamber, having
sundry series of oscillating duplex troughs pivoted in tiers within the drying
chamber, of cranks attached to the pivots outside the wall of the chamber, a lever
with connections to the said cranks to oscillate the same, an arm for vibrating said
lever, with a crank pin having reverse pawls fitted thereto and a reciprocating
carriage having the pawls pivoted thereon and provided with rotating cams adapted
to drop the pawls alternately upon the crank pin, as set forth.
7. In a drying apparatus, the combination, with a vertical chamber, of a feed
bin above the same, a discharge hopper below the same, and means for drawing
the air from the chamber below the feed bin and delivering it to the chamber
above the discharge hopper, as and for the purpose set forth.
8. In a drying apparatus, the combination, with a vertical drying chamber, of a
feed bin sustained above the top of the drying chamber, a discharge hopper
sustained below the bottom of the same, an air mixing chamber connected with
the drying chamber near the top, and a fan drawing the air from the mixing
chamber and delivering it to the drying chamber above the discharge hopper.
9. The method herein described for having the recirculated current in a drying
apparatus, which consists in replacing that portion of the air discharged with the
evaporated moisture by an equivalent of heated air or gas, as herein set forth.
Dated this 30th day of Norah A D 1905
THOMAS S. CRANE,
10 Wall Street, New York City, N.Y., Agent for the Applicant.